Postnatal development of GABAergic interneurons in the neocortical subplate of mice.

PubMed

Qu, G-J; Ma, J; Yu, Y-C; Fu, Y

2016-05-13

The subplate (SP) plays important roles in developmental and functional events in the neocortex, such as thalamocortical and corticofugal projection, cortical oscillation generation and corticocortical connectivity. Although accumulated evidence indicates that SP interneurons are crucial for SP function, the molecular composition of SP interneurons as well as their developmental profile and distribution remain largely unclear. In this study, we systematically investigated dynamic development of SP thickness and chemical marker expression in SP interneurons in distinct cortical regions during the first postnatal month. We found that, although the relative area of the SP in the cerebral cortex significantly declined with postnatal development, the absolute thickness did not change markedly. We also found that somatostatin (SOM), the ionotropic serotonin receptor 3A (5HT3AR), and parvalbumin (PV) reliably identify three distinct non-overlapping subpopulations of SP interneurons. The SOM group, which represents ~30% of total SP interneurons, expresses neuronal nitric oxide synthase (nNOS) and calbindin (CB) and colocalizes entirely with neuropeptide Y (NPY). The 5HT3AR group, which accounts for ~60% of the total interneuronal population, expresses calretinin (CR) and GABA-A receptor subunit delta (GABAARδ). The PV group accounts for ~10% of total SP interneurons and coexpressed GABAARδ. Moreover, distinct interneuron subtypes show characteristic temporal and spatial distribution in the SP. nNOS(+) interneurons in the SP increase from the anterior motor cortex to posterior visual cortex, while CR(+) and CB(+) interneurons the opposite. Interestedly, the majority of GABAARδ(+) neurons in SP are non-GABAergic neurons in contrast to other cortical layers. These findings clarify and extend our understanding of SP interneurons in the developing cerebral cortex and will underpin further study of SP function. Copyright © 2016 IBRO. Published by Elsevier Ltd. All rights reserved.

Subcellular Localization and Activity of TRPM4 in Medial Prefrontal Cortex Layer 2/3

PubMed Central

Riquelme, Denise; Silva, Ian; Philp, Ashleigh M.; Huidobro-Toro, Juan P.; Cerda, Oscar; Trimmer, James S.; Leiva-Salcedo, Elias

2018-01-01

TRPM4 is a Ca2+-activated non-selective cationic channel that conducts monovalent cations. TRPM4 has been proposed to contribute to burst firing and sustained activity in several brain regions, however, the cellular and subcellular pattern of TRPM4 expression in medial prefrontal cortex (mPFC) during postnatal development has not been elucidated. Here, we use multiplex immunofluorescence labeling of brain sections to characterize the postnatal developmental expression of TRPM4 in the mouse mPFC. We also performed electrophysiological recordings to correlate the expression of TRPM4 immunoreactivity with the presence of TRPM4-like currents. We found that TRPM4 is expressed from the first postnatal day, with expression increasing up to postnatal day 35. Additionally, in perforated patch clamp experiments, we found that TRPM4-like currents were active at resting membrane potentials at all postnatal ages studied. Moreover, TRPM4 is expressed in both pyramidal neurons and interneurons. TRPM4 expression is localized in the soma and proximal dendrites, but not in the axon initial segment of pyramidal neurons. This subcellular localization is consistent with a reduction in the basal current only when we locally perfused 9-Phenanthrol in the soma, but not upon perfusion in the medial or distal dendrites. Our results show a specific localization of TRPM4 expression in neurons in the mPFC and that a 9-Phenanthrol sensitive current is active at resting membrane potential, suggesting specific functional roles in mPFC neurons during postnatal development and in adulthood. PMID:29440991

Subcellular Localization and Activity of TRPM4 in Medial Prefrontal Cortex Layer 2/3.

PubMed

Riquelme, Denise; Silva, Ian; Philp, Ashleigh M; Huidobro-Toro, Juan P; Cerda, Oscar; Trimmer, James S; Leiva-Salcedo, Elias

2018-01-01

TRPM4 is a Ca 2+ -activated non-selective cationic channel that conducts monovalent cations. TRPM4 has been proposed to contribute to burst firing and sustained activity in several brain regions, however, the cellular and subcellular pattern of TRPM4 expression in medial prefrontal cortex (mPFC) during postnatal development has not been elucidated. Here, we use multiplex immunofluorescence labeling of brain sections to characterize the postnatal developmental expression of TRPM4 in the mouse mPFC. We also performed electrophysiological recordings to correlate the expression of TRPM4 immunoreactivity with the presence of TRPM4-like currents. We found that TRPM4 is expressed from the first postnatal day, with expression increasing up to postnatal day 35. Additionally, in perforated patch clamp experiments, we found that TRPM4-like currents were active at resting membrane potentials at all postnatal ages studied. Moreover, TRPM4 is expressed in both pyramidal neurons and interneurons. TRPM4 expression is localized in the soma and proximal dendrites, but not in the axon initial segment of pyramidal neurons. This subcellular localization is consistent with a reduction in the basal current only when we locally perfused 9-Phenanthrol in the soma, but not upon perfusion in the medial or distal dendrites. Our results show a specific localization of TRPM4 expression in neurons in the mPFC and that a 9-Phenanthrol sensitive current is active at resting membrane potential, suggesting specific functional roles in mPFC neurons during postnatal development and in adulthood.

Quantitative assessment of fibroblast growth factor receptor 1 expression in neurons and glia.

PubMed

Choubey, Lisha; Collette, Jantzen C; Smith, Karen Müller

2017-01-01

Fibroblast growth factors (FGFs) and their receptors (FGFRs) have numerous functions in the developing and adult central nervous system (CNS). For example, the FGFR1 receptor is important for proliferation and fate specification of radial glial cells in the cortex and hippocampus, oligodendrocyte proliferation and regeneration, midline glia morphology and soma translocation, Bergmann glia morphology, and cerebellar morphogenesis. In addition, FGFR1 signaling in astrocytes is required for postnatal maturation of interneurons expressing parvalbumin (PV). FGFR1 is implicated in synapse formation in the hippocampus, and alterations in the expression of Fgfr1 and its ligand, Fgf2 accompany major depression. Understanding which cell types express Fgfr1 during development may elucidate its roles in normal development of the brain as well as illuminate possible causes of certain neuropsychiatric disorders. Here, we used a BAC transgenic reporter line to trace Fgfr1 expression in the developing postnatal murine CNS. The specific transgenic line employed was created by the GENSAT project, tgFGFR1-EGFPGP338Gsat , and includes a gene encoding enhanced green fluorescent protein ( EGFP ) under the regulation of the Fgfr1 promoter, to trace Fgfr1 expression in the developing CNS. Unbiased stereological counts were performed for several cell types in the cortex and hippocampus. This model reveals that Fgfr1 is primarily expressed in glial cells, in both astrocytes and oligodendrocytes, along with some neurons. Dual labeling experiments indicate that the proportion of GFP+ ( Fgfr1 +) cells that are also GFAP+ increases from postnatal day 7 (P7) to 1 month, illuminating dynamic changes in Fgfr1 expression during postnatal development of the cortex. In postnatal neurogenic areas, GFP expression was also observed in SOX2, doublecortin (DCX), and brain lipid-binding protein (BLBP) expressing cells. Fgfr1 is also highly expressed in DCX positive cells of the dentate gyrus (DG), but not in the rostral migratory stream. Fgfr1 driven GFP was also observed in tanycytes and GFAP+ cells of the hypothalamus, as well as in Bergmann glia and astrocytes of the cerebellum. The tgFGFR1-EGFPGP338Gsat mouse model expresses GFP that is congruent with known functions of FGFR1, including hippocampal development, glial cell development, and stem cell proliferation. Understanding which cell types express Fgfr1 may elucidate its role in neuropsychiatric disorders and brain development.

Regional microstructural organization of the cerebral cortex is affected by preterm birth.

PubMed

Bouyssi-Kobar, Marine; Brossard-Racine, Marie; Jacobs, Marni; Murnick, Jonathan; Chang, Taeun; Limperopoulos, Catherine

2018-01-01

To compare regional cerebral cortical microstructural organization between preterm infants at term-equivalent age (TEA) and healthy full-term newborns, and to examine the impact of clinical risk factors on cerebral cortical micro-organization in the preterm cohort. We prospectively enrolled very preterm infants (gestational age (GA) at birth<32 weeks; birthweight<1500 g) and healthy full-term controls. Using non-invasive 3T diffusion tensor imaging (DTI) metrics, we quantified regional micro-organization in ten cerebral cortical areas: medial/dorsolateral prefrontal cortex, anterior/posterior cingulate cortex, insula, posterior parietal cortex, motor/somatosensory/auditory/visual cortex. ANCOVA analyses were performed controlling for sex and postmenstrual age at MRI. We studied 91 preterm infants at TEA and 69 full-term controls. Preterm infants demonstrated significantly higher diffusivity in the prefrontal, parietal, motor, somatosensory, and visual cortices suggesting delayed maturation of these cortical areas. Additionally, postnatal hydrocortisone treatment was related to accelerated microstructural organization in the prefrontal and somatosensory cortices. Preterm birth alters regional microstructural organization of the cerebral cortex in both neurocognitive brain regions and areas with primary sensory/motor functions. We also report for the first time a potential protective effect of postnatal hydrocortisone administration on cerebral cortical development in preterm infants.

Dynamic changes in DNA demethylation in the tree shrew (Tupaia belangeri chinensis) brain during postnatal development and aging.

PubMed

Wei, Shu; Hua, Hai-Rong; Chen, Qian-Quan; Zhang, Ying; Chen, Fei; Li, Shu-Qing; Li, Fan; Li, Jia-Li

2017-03-18

Brain development and aging are associated with alterations in multiple epigenetic systems, including DNA methylation and demethylation patterns. Here, we observed that the levels of the 5-hydroxymethylcytosine (5hmC) ten-eleven translocation (TET) enzyme-mediated active DNA demethylation products were dynamically changed and involved in postnatal brain development and aging in tree shrews ( Tupaia belangeri chinensis ). The levels of 5hmC in multiple anatomic structures showed a gradual increase throughout postnatal development, whereas a significant decrease in 5hmC was found in several brain regions in aged tree shrews, including in the prefrontal cortex and hippocampus, but not the cerebellum. Active changes in Tet mRNA levels indicated that TET2 and TET3 predominantly contributed to the changes in 5hmC levels. Our findings provide new insight into the dynamic changes in 5hmC levels in tree shrew brains during postnatal development and aging processes.

Pleiotropic Effects of Neurotransmission during Development: Modulators of Modularity

ERIC Educational Resources Information Center

Thompson, Barbara L.; Stanwood, Gregg D.

2009-01-01

The formation and function of the mammalian cerebral cortex relies on the complex interplay of a variety of genetic and environmental factors through protracted periods of gestational and postnatal development. Biogenic amine systems are important neuromodulators, both in the adult nervous system, and during critical epochs of brain development.…

Synchronized changes to relative neuron populations in postnatal human neocortical development

PubMed Central

Cooper, David L.; Gentle, James E.; Barreto, Ernest

2010-01-01

Mammalian prenatal neocortical development is dominated by the synchronized formation of the laminae and migration of neurons. Postnatal development likewise contains “sensitive periods” during which functions such as ocular dominance emerge. Here we introduce a novel neuroinformatics approach to identify and study these periods of active development. Although many aspects of the approach can be used in other studies, some specific techniques were chosen because of a legacy dataset of human histological data (Conel in The postnatal development of the human cerebral cortex, vol 1–8. Harvard University Press, Cambridge, 1939–1967). Our method calculates normalized change vectors from the raw histological data, and then employs k-means cluster analysis of the change vectors to explore the population dynamics of neurons from 37 neocortical areas across eight postnatal developmental stages from birth to 72 months in 54 subjects. We show that the cortical “address” (Brodmann area/sub-area and layer) provides the necessary resolution to segregate neuron population changes into seven correlated “k-clusters” in k-means cluster analysis. The members in each k-cluster share a single change interval where the relative share of the cortex by the members undergoes its maximum change. The maximum change occurs in a different change interval for each k-cluster. Each k-cluster has at least one totally connected maximal “clique” which appears to correspond to cortical function. Electronic supplementary material The online version of this article (doi:10.1007/s11571-010-9103-3) contains supplementary material, which is available to authorized users. PMID:21629587

Maternal Dietary Choline Status Influences Brain Gray and White Matter Development in Young Pigs

PubMed Central

Mudd, Austin T; Getty, Caitlyn M; Dilger, Ryan N

2018-01-01

Abstract Background Choline is an essential nutrient that is pivotal to proper brain development. Research in animal models suggests that perinatal choline deficiency influences neuron development in the hippocampus and cortex, yet these observations require invasive techniques. Objective This study aimed to characterize the effects of perinatal choline deficiency on gray and white matter development with the use of noninvasive neuroimaging techniques in young pigs. Methods During the last 64 d of the 114-d gestation period Yorkshire sows were provided with a choline-sufficient (CS) or choline-deficient (CD) diet, analyzed to contain 1214 mg or 483 mg total choline/kg diet, respectively. Upon farrowing, pigs (Sus scrofa domesticus) were allowed colostrum consumption for ≤48 h, were further stratified into postnatal treatment groups, and were provided either CS or CD milk replacers, analyzed to contain 1591 or 518 mg total choline/kg diet, respectively, for 28 d. At 30 d of age, pigs were subjected to MRI procedures to assess brain development. Gray and white matter development was assessed through voxel-based morphometry (VBM) and tract-based spatial statistics (TBSS) to assess the effects of prenatal and postnatal dietary choline status. Results VBM analysis indicated that prenatally CS pigs exhibited increased (P < 0.01) gray matter in the left and right cortex compared with prenatally CD pigs. Analysis of white matter indicated that prenatally CS pigs exhibited increased (P < 0.01) white matter in the internal capsule, putamen–globus pallidus, and right cortex compared with prenatally CD pigs. No postnatal effects (P > 0.05) of choline status were noted for VBM analyses of gray and white matter. TBSS also showed no significant effects (P > 0.05) of prenatal or postnatal choline status for diffusion values along white matter tracts. Conclusions Observations from this study suggest that prenatal choline deficiency results in altered cortical gray matter and reduced white matter in the internal capsule and putamen of young pigs. With the use of noninvasive neuroimaging techniques, results from our study indicate that prenatal choline deficiency greatly alters gray and white matter development in pigs, thereby providing a translational assessment that may be used in clinical populations.

Zinc histochemistry reveals circuit refinement and distinguishes visual areas in the developing ferret cerebral cortex.

PubMed

Khalil, Reem; Levitt, Jonathan B

2013-09-01

A critical question in brain development is whether different brain circuits mature concurrently or with different timescales. To characterize the anatomical and functional development of different visual cortical areas, one must be able to distinguish these areas. Here, we show that zinc histochemistry, which reveals a subset of glutamatergic processes, can be used to reliably distinguish visual areas in juvenile and adult ferret cerebral cortex, and that the postnatal decline in levels of synaptic zinc follows a broadly similar developmental trajectory in multiple areas of ferret visual cortex. Zinc staining in all areas examined (17, 18, 19, 21, and Suprasylvian) is greater in the 5-week-old than in the adult. Furthermore, there is less laminar variation in zinc staining in the 5-week-old visual cortex than in the adult. Despite differences in staining intensity, areal boundaries can be discerned in the juvenile as in the adult. By 6 weeks of age, we observe a significant decline in visual cortical synaptic zinc; this decline was most pronounced in layer IV of areas 17 and 18, with much less change in higher-order extrastriate areas during the important period in visual cortical development following eye opening. By 10 weeks of age, the laminar pattern of zinc staining in all visual areas is essentially adultlike. The decline in synaptic zinc in the supra- and infragranular layers in all areas proceeds at the same rate, though the decline in layer IV does not. These results suggest that the timecourse of synaptic zinc decline is lamina specific, and further confirm and extend the notion that at least some aspects of cortical maturation follow a similar developmental timecourse in multiple areas. The postnatal decline in synaptic zinc we observe during the second postnatal month begins after eye opening, consistent with evidence that synaptic zinc is regulated by sensory experience.

Sensorimotor development in neonatal progesterone receptor knockout mice.

PubMed

Willing, Jari; Wagner, Christine K

2014-01-01

Early exposure to steroid hormones can permanently and dramatically alter neural development. This is best understood in the organizational effects of hormones during development of brain regions involved in reproductive behaviors or neuroendocrine function. However, recent evidence strongly suggests that steroid hormones play a vital role in shaping brain regions involved in cognitive behavior such as the cerebral cortex. The most abundantly expressed steroid hormone receptor in the developing rodent cortex is the progesterone receptor (PR). In the rat, PR is initially expressed in the developmentally-critical subplate at E18, and subsequently in laminas V and II/III through the first three postnatal weeks (Quadros et al. [2007] J Comp Neurol 504:42-56; Lopez & Wagner [2009]: J Comp Neurol 512:124-139), coinciding with significant periods of dendritic maturation, the arrival of afferents and synaptogenesis. In the present study, we investigated PR expression in the neonatal mouse somatosensory cortex. Additionally, to investigate the potential role of PR in developing cortex, we examined sensorimotor function in the first two postnatal weeks in PR knockout mice and their wildtype (WT) and heterozygous (HZ) counterparts. While the three genotypes were similar in most regards, PRKO and HZ mice lost the rooting reflex 2-3 days earlier than WT mice. These studies represent the first developmental behavioral assessment of PRKO mice and suggest PR expression may play an important role in the maturation of cortical connectivity and sensorimotor integration. Copyright © 2013 Wiley Periodicals, Inc.

Reelin-Haploinsufficiency Disrupts the Developmental Trajectory of the E/I Balance in the Prefrontal Cortex

PubMed Central

Bouamrane, Lamine; Scheyer, Andrew F.; Lassalle, Olivier; Iafrati, Jillian; Thomazeau, Aurore; Chavis, Pascale

2017-01-01

The reelin gene is a strong candidate in the etiology of several psychiatric disorders such as schizophrenia, major depression, bipolar disorders, and autism spectrum disorders. Most of these diseases are accompanied by cognitive and executive-function deficits associated with prefrontal dysfunctions. Mammalian prefrontal cortex (PFC) development is characterized by a protracted postnatal maturation constituting a period of enhanced vulnerability to psychiatric insults. The identification of the molecular components underlying this prolonged postnatal development is necessary to understand the synaptic properties of defective circuits participating in these psychiatric disorders. We have recently shown that reelin plays a key role in the maturation of glutamatergic functions in the postnatal PFC, but no data are available regarding the GABAergic circuits. Here, we undertook a cross-sectional analysis of GABAergic function in deep layer pyramidal neurons of the medial PFC of wild-type and haploinsufficient heterozygous reeler mice. Using electrophysiological approaches, we showed that decreased reelin levels impair the maturation of GABAergic synaptic transmission without affecting the inhibitory nature of GABA. This phenotype consequently impacted the developmental sequence of the synaptic excitation/inhibition (E/I) balance. These data indicate that reelin is necessary for the correct maturation and refinement of GABAergic synaptic circuits in the postnatal PFC and therefore provide a mechanism for altered E/I balance of prefrontal circuits associated with psychiatric disorders. PMID:28127276

Hyperconnectivity of prefrontal cortex to amygdala projections in a mouse model of macrocephaly/autism syndrome.

PubMed

Huang, Wen-Chin; Chen, Youjun; Page, Damon T

2016-11-15

Multiple autism risk genes converge on the regulation of mTOR signalling, which is a key effector of neuronal growth and connectivity. We show that mTOR signalling is dysregulated during early postnatal development in the cerebral cortex of germ-line heterozygous Pten mutant mice (Pten +/- ), which model macrocephaly/autism syndrome. The basolateral amygdala (BLA) receives input from subcortical-projecting neurons in the medial prefrontal cortex (mPFC). Analysis of mPFC to BLA axonal projections reveals that Pten +/- mice exhibit increased axonal branching and connectivity, which is accompanied by increased activity in the BLA in response to social stimuli and social behavioural deficits. The latter two phenotypes can be suppressed by pharmacological inhibition of S6K1 during early postnatal life or by reducing the activity of mPFC-BLA circuitry in adulthood. These findings identify a mechanism of altered connectivity that has potential relevance to the pathophysiology of macrocephaly/autism syndrome and autism spectrum disorders featuring dysregulated mTOR signalling.

Hyperconnectivity of prefrontal cortex to amygdala projections in a mouse model of macrocephaly/autism syndrome

PubMed Central

Huang, Wen-Chin; Chen, Youjun; Page, Damon T.

2016-01-01

Multiple autism risk genes converge on the regulation of mTOR signalling, which is a key effector of neuronal growth and connectivity. We show that mTOR signalling is dysregulated during early postnatal development in the cerebral cortex of germ-line heterozygous Pten mutant mice (Pten+/−), which model macrocephaly/autism syndrome. The basolateral amygdala (BLA) receives input from subcortical-projecting neurons in the medial prefrontal cortex (mPFC). Analysis of mPFC to BLA axonal projections reveals that Pten+/− mice exhibit increased axonal branching and connectivity, which is accompanied by increased activity in the BLA in response to social stimuli and social behavioural deficits. The latter two phenotypes can be suppressed by pharmacological inhibition of S6K1 during early postnatal life or by reducing the activity of mPFC–BLA circuitry in adulthood. These findings identify a mechanism of altered connectivity that has potential relevance to the pathophysiology of macrocephaly/autism syndrome and autism spectrum disorders featuring dysregulated mTOR signalling. PMID:27845329

Endocannabinoid signaling is required for development and critical period plasticity of the whisker map in somatosensory cortex

PubMed Central

Li, Lu; Bender, Kevin J.; Drew, Patrick J.; Jadhav, Shantanu P.; Sylwestrak, Emily; Feldman, Daniel E.

2009-01-01

Summary Type 1 cannabinoid (CB1) receptors mediate widespread synaptic plasticity, but how this contributes to systems-level plasticity and development in vivo is unclear. We tested whether CB1 signaling is required for development and plasticity of the whisker map in rat somatosensory cortex. Treatment with the CB1 antagonist AM251 during an early critical period for layer (L) 2/3 development (beginning postnatal day [P] 12–16) disrupted whisker map development, leading to inappropriate whisker tuning in L2/3 column edges and a blurred map. Early AM251 treatment also prevented experience-dependent plasticity in L2/3, including deprivation-induced synapse weakening and weakening of deprived whisker responses. CB1 blockade after P25 did not disrupt map development or plasticity. AM251 had no acute effect on sensory-evoked spiking, and only modestly affected field potentials, suggesting that plasticity effects were not secondary to gross activity changes. These findings implicate CB1-dependent plasticity in systems-level development and early postnatal plasticity of the whisker map. PMID:19945395

Structural stabilization of CNS synapses during postnatal development in rat cortex.

PubMed

Khaing, Zin Z; Fidler, Lazar; Nandy, Nina; Phillips, Greg R

2006-07-01

CNS synapses are produced rapidly upon pre- and post-synaptic recruitment. However, their composition is known to change during development and we reasoned that this may be reflected in the gross biochemical properties of synapses. We found synaptic structure in adult cortical synaptosomes to be resistant to digestion with trypsin in the presence and absence of calcium ions, contrasting with previous observations. We evaluated the divalent cation dependence and trypsin sensitivities of synapses using synaptosomes from different developmental stages. In contrast to adult synapses, at postnatal day (P) 10 EDTA treatment eliminated approximately 60% of the synapses, and trypsin and EDTA, together, eliminated all junctions. Trypsinization in the presence of calcium eliminated approximately 60% of the junctions at P10. By P35, all synapses were calcium independent, whereas full trypsin resistance was not attained until P49. To compare the calcium dependence and trypsin sensitivity of synapses in another region of the adult brain, we examined synapses from adult (P50) hippocampus. Adult hippocampus maintained a population of synapses that resembled that of P35 cortex. Our results show that synapses are modified over a long time period in the developing cortex. We propose a model in which the addition of synergistic calcium-dependent and -independent adhesive systems stabilize synapses.

Preprotachykinin A mRNA expression in the rat brain during development.

PubMed

Brené, S; Lindefors, N; Friedman, W J; Persson, H

1990-12-15

Expression of preprotachykinin A (PPT-A) mRNA was analyzed by northern blots using mRNA prepared from rat brain at 12 different developmental stages ranging from embryonic day 15 (E15) to adult. A single PPT-A mRNA of 1.3 kb was detected throughout development. PPT-A mRNA was detected as early as E15 and an approximately 3-fold increase occurred at birth. This amount remained until 3 weeks of age when the level increased, reaching a peak at 5 weeks of age. Adult amounts were approximately 3-fold higher than the levels at birth. The distribution of PPT-A mRNA-expressing cells in rat brain was studied by in situ hybridization on sections from embryonic day 20, postnatal days 4 and 7 as well as adult. Cells expressing PPT-A mRNA were detected in the forebrain at all 4 ages analyzed. However, the hybridization pattern and the labeling intensity varied in different brain regions during development. In cingulate cortex, intense labeling was seen in numerous cells at embryonic day 20 and postnatal days 4 and 7, whereas in the adult cingulate cortex only a few scattered labeled cells were observed. In frontoparietal cortex labeled cells were found from postnatal day 4 to adult, with the highest density of labeled cells at P7. Developmental differences in both the distribution of PPT-A mRNA-expressing cells and the level of PPT-A mRNA expression were also found in caudate-putamen, lateral hypothalamus and amygdala. Thus, our results show several changes in PPT-A mRNA expression during ontogeny, indicating a region and time-specific regulation of PPT-A mRNA expression during brain maturation.

Experience-dependent increase in spine calcium evoked by backpropagating action potentials in layer 2/3 pyramidal neurons in rat somatosensory cortex.

PubMed

Krieger, Patrik

2009-11-01

In spines on basal dendrites of layer 2/3 pyramidal neurons in somatosensory barrel cortex, calcium transients evoked by back-propagating action potentials (bAPs) were investigated (i) along the length of the basal dendrite, (ii) with postnatal development and (iii) with sensory deprivation during postnatal development. Layer 2/3 pyramidal neurons were investigated at three different ages. At all ages [postnatal day (P)8, P14, P21] the bAP-evoked calcium transient amplitude increased with distance from the soma with a peak at around 50 microm, followed by a gradual decline in amplitude. The effect of sensory deprivation on the bAP-evoked calcium was investigated using two different protocols. When all whiskers on one side of the rat snout were trimmed daily from P8 to P20-24 there was no difference in the bAP-evoked calcium transient between cells in the contralateral hemisphere, lacking sensory input from the whisker, and cells in the ipsilateral barrel cortex, with intact whisker activation. When, however, only the D-row whiskers on one side were trimmed the distribution of bAP-evoked calcium transients in spines was shifted towards larger amplitudes in cells located in the deprived D-column. In conclusion, (i) the bAP-evoked calcium transient gradient along the dendrite length is established at P8, (ii) the calcium transient increases in amplitude with age and (iii) this increase is enhanced in layer 2/3 pyramidal neurons located in a sensory-deprived barrel column that is bordered by non-deprived barrel columns.

Development of thalamocortical connections between the mediodorsal thalamus and the prefrontal cortex and its implication in cognition

PubMed Central

Ferguson, Brielle R.; Gao, Wen-Jun

2015-01-01

The mediodorsal thalamus (MD) represents a fundamental subcortical relay to the prefrontal cortex (PFC), and is thought to be highly implicated in modulation of cognitive performance. Additionally, it undergoes highly conserved developmental stages, which, when dysregulated, can have detrimental consequences. Embryonically, the MD experiences a tremendous surge in neurogenesis and differentiation, and disruption of this process may underlie the pathology in certain neurodevelopmental disorders. However, during the postnatal period, a vast amount of cell loss in the MD occurs. These together may represent an extended critical period for postnatal development, in which disturbances in the normal growth or reduction of the MD afferents to the PFC, can result in PFC-dependent cognitive, affective, or psychotic abnormalities. In this review, we explore the current knowledge supporting this hypothesis of a protracted critical period, and propose how developmental changes in the MD contribute to successful prefrontal cortical development and function. Specifically, we elaborate on the unique properties of MD-PFC connections compared with other thalamocortical afferents in sensory cortices, examine how MD-PFC innervation modulates synaptic transmission in the local prefrontal circuitry, and speculate on what occurs during postnatal development, particularly within the early neonatal stage, as well as juvenile and adolescent periods. Finally, we discuss the questions that remain and propose future experiments in order to provide perspective and novel insights into the cause of neuropsychiatric disorders associated with MD-PFC development. PMID:25620923

Skilled movements require non-apoptotic Bax/Bak pathway-mediated corticospinal circuit reorganization

PubMed Central

Gu, Zirong; Serradj, Najet; Ueno, Masaki; Liang, Mishi; Li, Jie; Baccei, Mark L.; Martin, John H.; Yoshida, Yutaka

2017-01-01

Early postnatal mammals, including human babies, can perform only basic motor tasks. The acquisition of skilled behaviors occurs later, requiring anatomical changes in neural circuitry to support the development of coordinated activation or suppression of functionally related muscle groups. How this circuit reorganization occurs during postnatal development remains poorly understood. Here we explore the connectivity between corticospinal (CS) neurons in the motor cortex and muscles in mice. Using trans-synaptic viral and electrophysiological assays, we identify the early postnatal reorganization of CS circuitry for antagonistic muscle pairs. We further show that this synaptic rearrangement requires the activity-dependent, non-apoptotic Bax/Bak-caspase signaling cascade. Adult Bax/Bak mutant mice exhibit aberrant co-activation of antagonistic muscle pairs and skilled grasping deficits but normal reaching and retrieval behaviors. Our findings reveal key cellular and molecular mechanisms driving postnatal motor circuit reorganization and the resulting impacts on muscle activation patterns and the execution of skilled movements. PMID:28472660

A morphological and electrophysiological study on the postnatal development of oligodendrocyte precursor cells in the rat brain.

PubMed

Chen, Peng-hui; Cai, Wen-qin; Wang, Li-yan; Deng, Qi-yue

2008-12-03

A widespread population of cells in CNS is identified by specific expression of the NG2 chondroitin sulphate proteoglycan and named as oligodendrocyte precursor cell (OPC). OPCs may possess stem cell-like characteristics, including multipotentiality in vitro and in vivo. It was proposed that OPCs in the CNS parenchyma comprise a unique population of glia, distinct from oligodendrocytes and astrocytes. This study confirmed that NG2 immunoreactive OPCs were continuously distributed in cerebral cortex and hippocampus during different postnatal developmental stages. These cells rapidly increased in number over the postnatal 7 days and migrate extensively to populate with abundant processes both in developing cortex and hippocampus. The morphology of OPCs exhibited extremely complex changes with the distribution of long distance primary process gradually increased from neonatal to adult CNS. Immunohistochemical studies showed that OPCs exhibited the morphological properties that can be distinguished from astrocytes. The electrophysiological properties showed that OPCs expressed a small amount of inward Na(+) currents which was distinguished from Na(+) currents in neurons owing to their lower Na-to-K conductance ratio and higher command voltage step depolarized maximum Na(+) current amplitude. These observations suggest that OPCs can be identified as the third type of macroglia because of their distribution in the CNS, the morphological development in process diversity and the electrophysiological difference from astrocyte.

Postnatal Administration of Dizocilpine Inhibits Neuronal Excitability in PFC and Induces Social Deficits Detected by MiceProfiler.

PubMed

Zhu, Dexiao; Wang, Hui; Wu, Jintao; Wang, Qian; Xu, Ling; Zhao, Yue; Pang, Kunkun; Shi, Qingqing; Zhao, Wenbo; Zhang, Jing; Sun, Jinhao

2017-12-01

Schizophrenia is a devastating mental disease with social deficit as its core component of negative symptoms, which could be induced in rodents by dizocilpine (MK-801), a noncompetitive NMDA receptor antagonist. NMDA receptors are highly expressed during the postnatal period. However, less attention has been paid to the effects of postnatal MK-801 administration on social interaction. In this study, we evaluated the effects of postnatal administration of MK-801 on social interaction and explored the possible mechanisms. Postnatal day-7 mice were intraperitoneally injected with MK-801 twice daily for 5 days, and their social interaction repertoire was monitored by a computerized video in the 10th week. The contact event, relative position event, stop-state, and dynamic event were analyzed with MiceProfiler automatic idTracker system. The results showed that MK-801 reduced the number of the contact events, relative position events, and stop-states, while increased the number and duration of dynamic events. These changes implied that MK-801-injected mice had indifference and lower motivation in social interaction and could be a useful model for studies on the social deficit of schizophrenia. The prefrontal cortex is the key region for social interaction behaviors. Slice patch clamp was performed to analyze the cellular excitability of prefrontal cortical neurons after postnatal treatment with MK-801 in mice. The results demonstrated that MK-801 injection reduced the frequency and amplitude of action potentials, but increased the frequency of miniature inhibitory postsynaptic currents. These data illustrated that the excitability of neurons in the prefrontal cortex was inhibited. Finally, immunoblotting data demonstrated that MK-801 significantly decreased the levels of sirtuin 1 (SIRT1) and phosphorylated protein kinase B (p-PKB) in the prefrontal cortex (both P < 0.05). Taken together, our results indicated that administration of MK-801 to postnatal mice induces social interaction deficits possibly due to inhibiting the neuronal excitability and decreasing the levels of SIRT1 and p-PKB in the prefrontal cortex.

Expression profiling of mouse subplate reveals a dynamic gene network and disease association with autism and schizophrenia

PubMed Central

Hoerder-Suabedissen, Anna; Oeschger, Franziska M.; Krishnan, Michelle L.; Belgard, T. Grant; Wang, Wei Zhi; Lee, Sheena; Webber, Caleb; Petretto, Enrico; Edwards, A. David; Molnár, Zoltán

2013-01-01

The subplate zone is a highly dynamic transient sector of the developing cerebral cortex that contains some of the earliest generated neurons and the first functional synapses of the cerebral cortex. Subplate cells have important functions in early establishment and maturation of thalamocortical connections, as well as in the development of inhibitory cortical circuits in sensory areas. So far no role has been identified for cells in the subplate in the mature brain and disease association of the subplate-specific genes has not been analyzed systematically. Here we present gene expression evidence for distinct roles of the mouse subplate across development as well as unique molecular markers to extend the repertoire of subplate labels. Performing systematic comparisons between different ages (embryonic days 15 and 18, postnatal day 8, and adult), we reveal the dynamic and constant features of the markers labeling subplate cells during embryonic and early postnatal development and in the adult. This can be visualized using the online database of subplate gene expression at https://molnar.dpag.ox.ac.uk/subplate/. We also identify embryonic similarities in gene expression between the ventricular zones, intermediate zone, and subplate, and distinct postnatal similarities between subplate, layer 5, and layers 2/3. The genes expressed in a subplate-specific manner at some point during development show a statistically significant enrichment for association with autism spectrum disorders and schizophrenia. Our report emphasizes the importance of the study of transient features of the developing brain to better understand neurodevelopmental disorders. PMID:23401504

Postnatal Erythropoietin Mitigates Impaired Cerebral Cortical Development Following Subplate Loss from Prenatal Hypoxia–Ischemia

PubMed Central

Jantzie, Lauren L.; Corbett, Christopher J.; Firl, Daniel J.; Robinson, Shenandoah

2015-01-01

Preterm birth impacts brain development and leads to chronic deficits including cognitive delay, behavioral problems, and epilepsy. Premature loss of the subplate, a transient subcortical layer that guides development of the cerebral cortex and axonal refinement, has been implicated in these neurological disorders. Subplate neurons influence postnatal upregulation of the potassium chloride co-transporter KCC2 and maturation of γ-amino-butyric acid A receptor (GABAAR) subunits. We hypothesized that prenatal transient systemic hypoxia–ischemia (TSHI) in Sprague–Dawley rats that mimic brain injury from extreme prematurity in humans would cause premature subplate loss and affect cortical layer IV development. Further, we predicted that the neuroprotective agent erythropoietin (EPO) could attenuate the injury. Prenatal TSHI induced subplate neuronal loss via apoptosis. TSHI impaired cortical layer IV postnatal upregulation of KCC2 and GABAAR subunits, and postnatal EPO treatment mitigated the loss (n ≥ 8). To specifically address how subplate loss affects cortical development, we used in vitro mechanical subplate ablation in slice cultures (n ≥ 3) and found EPO treatment attenuates KCC2 loss. Together, these results show that subplate loss contributes to impaired cerebral development, and EPO treatment diminishes the damage. Limitation of premature subplate loss and the resultant impaired cortical development may minimize cerebral deficits suffered by extremely preterm infants. PMID:24722771

Cell proliferation and apoptosis during histogenesis of the guinea pig and rabbit cerebellar cortex.

PubMed

Lossi, Laura; Coli, Alessandra; Giannessi, Elisabetta; Stornelli, Maria Rita; Marroni, Paolo

2002-01-01

Cell proliferation and apoptosis are essential for development of the nervous system. In this study we have investigated the histogenesis of the cerebellar cortex in guinea pig (a precocial species) and rabbit (an altricial species) at different stages of pregnancy and postnatal life. Proliferating cells were identified after labeling with antibodies against the proliferating cell nuclear antigen (PCNA) and/or the Ki-67 antigen. Apoptotic cells were visualized in situ by the TUNEL method and by immunodetection of cleaved caspase 3 and 9. In guinea pigs, both proliferating and apoptotic cells were detected during pre-natal life (E0-E40). Conversely, cell proliferation and apoptosis in rabbits were temporally restricted to early postnatal weeks (P0-P20). In both species cell proliferation was mainly linked to differentiation and migration of the granule cells. In both species, the majority of cells undergoing programmed cell death likely corresponded to granule cells. They were mainly detected in the external granular layer, and were by far more common than previously reported in other locations of the postnatal brain. This study shows that apoptosis is a shared process of cell death during cerebellar development in both altricial and precocial animals, and that there is a direct spatial and temporal correlation between cell proliferation and death in two mammals with different time tables in cerebellar maturation.

[The administration of interleukin-1beta during early postnatal develop ment impairs FGF2, but not TIMP1, mRNA expression in brain structures of adult rats].

PubMed

Trofimov, A N; Zubareva, O E; Shvarts, A P; Ishchenko, A M; Klimenko, V M

2014-09-01

According to the Neurodevelopmental hypothesis, the long-lasting cognitive deficit in schizophrenia and other types of neuropathology may occur by injurious factors, such as hypoxia, traumas, infections that take place during pre- and postnatal development, at least at early stages. These pathological conditions are often associated with the high production of pro-inflammatory cytokine interleukin-1B (IL-1B) by the cells of immune and nervous systems. We investigated the expression of genes involved in the neuroplastic regulation (Fgf2 and Timp2) in medial prefrontal cortex and dorsal and ventral regions of hippocampus of adult rats that were treated with IL-1beta between P15 and P21. The learning impairment in IL-1beta-treated rats is accompanied by lower FGF-2 mRNA levels in medial prefrontal cortex and ventral (not dorsal) hippocampus, but TIMP-1 was not affected. No differences in TIMP-1 and FGF-2 mRNA expressions were observed in untrained IL-1beta-treated when compared to control rats.

Regulation of microglial development: a novel role for thyroid hormone.

PubMed

Lima, F R; Gervais, A; Colin, C; Izembart, M; Neto, V M; Mallat, M

2001-03-15

The postnatal development of rat microglia is marked by an important increase in the number of microglial cells and the growth of their ramified processes. We studied the role of thyroid hormone in microglial development. The distribution and morphology of microglial cells stained with isolectin B4 or monoclonal antibody ED1 were analyzed in cortical and subcortical forebrain regions of developing rats rendered hypothyroid by prenatal and postnatal treatment with methyl-thiouracil. Microglial processes were markedly less abundant in hypothyroid pups than in age-matched normal animals, from postnatal day 4 up to the end of the third postnatal week of life. A delay in process extension and a decrease in the density of microglial cell bodies, as shown by cell counts in the developing cingulate cortex of normal and hypothyroid animals, were responsible for these differences. Conversely, neonatal rat hyperthyroidism, induced by daily injections of 3,5,3'-triiodothyronine (T3), accelerated the extension of microglial processes and increased the density of cortical microglial cell bodies above physiological levels during the first postnatal week of life. Reverse transcription-PCR and immunological analyses indicated that cultured cortical ameboid microglial cells expressed the alpha1 and beta1 isoforms of nuclear thyroid hormone receptors. Consistent with the trophic and morphogenetic effects of thyroid hormone observed in situ, T3 favored the survival of cultured purified microglial cells and the growth of their processes. These results demonstrate that thyroid hormone promotes the growth and morphological differentiation of microglia during development.

Regulation of the neurotensin NT1 receptor in the developing rat brain following chronic treatment with the antagonist SR 48692

PubMed Central

Lépée-Lorgeoux, Isabelle; Betancur, Catalina; Souazé, Frédérique; Rostène, William; Bérod, Anne; Pélaprat, Didier

2000-01-01

The aim of the present study was to investigate the role of neurotensin in the regulation of NT1 receptors during postnatal development in the rat brain. Characterization of the ontogeny of neurotensin concentration and [125I]neurotensin binding to NT1 receptors in the brain at different embryonic and postnatal stages showed that neurotensin was highly expressed at birth, reaching peak levels at postnatal day 5 (P5), and decreasing thereafter. The transient rise in neurotensin levels preceded the maximal expression of NT1 receptors, observed at P10, suggesting that neurotensin may influence the developmental profile of NT1 receptors. Using primary cultures of cerebral cortex neurons from fetal rats, we showed that exposure to the neurotensin agonist JMV 449 (1 nM) decreased (−43%) the amount of NT1 receptor mRNA measured by reverse transcription-PCR, an effect that was abolished by the non-peptide NT1 receptor antagonist SR 48692 (1 μM). However, daily injection of SR 48692 to rat pups from birth for 5, 9 or 15 days, did not modify [125I]neurotensin binding in brain membrane homogenates. Moreover, postnatal blockade of neurotensin transmission did not alter the density and distribution of NT1 receptors assessed by quantitative autoradiography nor NT1 receptor mRNA expression measured by in situ hybridization in the cerebral cortex, caudate-putamen and midbrain. These results suggest that although NT1 receptor expression can be regulated in vitro by the agonist at an early developmental stage, neurotensin is not a major factor in the establishment of the ontogenetic pattern of these receptors in the rat brain. PMID:10797539

Perineuronal Net Protein Neurocan Inhibits NCAM/EphA3 Repellent Signaling in GABAergic Interneurons.

PubMed

Sullivan, Chelsea S; Gotthard, Ingo; Wyatt, Elliott V; Bongu, Srihita; Mohan, Vishwa; Weinberg, Richard J; Maness, Patricia F

2018-04-18

Perineuronal nets (PNNs) are implicated in closure of critical periods of synaptic plasticity in the brain, but the molecular mechanisms by which PNNs regulate synapse development are obscure. A receptor complex of NCAM and EphA3 mediates postnatal remodeling of inhibitory perisomatic synapses of GABAergic interneurons onto pyramidal cells in the mouse frontal cortex necessary for excitatory/inhibitory balance. Here it is shown that enzymatic removal of PNN glycosaminoglycan chains decreased the density of GABAergic perisomatic synapses in mouse organotypic cortical slice cultures. Neurocan, a key component of PNNs, was expressed in postnatal frontal cortex in apposition to perisomatic synapses of parvalbumin-positive interneurons. Polysialylated NCAM (PSA-NCAM), which is required for ephrin-dependent synapse remodeling, bound less efficiently to neurocan than mature, non-PSA-NCAM. Neurocan bound the non-polysialylated form of NCAM at the EphA3 binding site within the immunoglobulin-2 domain. Neurocan inhibited NCAM/EphA3 association, membrane clustering of NCAM/EphA3 in cortical interneuron axons, EphA3 kinase activation, and ephrin-A5-induced growth cone collapse. These studies delineate a novel mechanism wherein neurocan inhibits NCAM/EphA3 signaling and axonal repulsion, which may terminate postnatal remodeling of interneuron axons to stabilize perisomatic synapses in vivo.

[Effects of postnatal lambda-cyhalothrin exposure on synaptic proteins in ICR mouse brain].

PubMed

Bao, Xun-Di; Wang, Qu-Nan; Li, Fang-Fang; Chai, Xiao-Yu; Gao, Ye

2011-04-01

To evaluate the influence on the synaptic protein expression in different brain regions of ICR mice after lambda-cyhalothrin (LCT) exposure during postnatal period. Two male and 4 female healthy ICR mice were put in one cage. It was set as pregnancy if vaginal plug was founded. Offspring were divided into 5 groups randomly, and exposed to LCT (0.01% DMSO solution) at the doses of 0.1, 1.0 and 10.0 mg/kg by intragastric rout every other day from postnatal days (PND) 5 to PND13, control animals were treated with normal saline or DMSO by the same route. The brains were removed from pups on PND 14, the synaptic protein expression levels in cortex, hippocampus and striatum were measured by western blot. GFAP levels of cortex and hippocampus in the LCT exposure group increased with doses, as compared with control group (P < 0.05), while Tuj protein expression did not change significantly in the various brain regions of ICR mice. GAP-43 protein expression levels in the LCT exposed mouse hippocampus and in female ICR mouse cortex increased with doses, as compared with control group (P < 0.05). Presynaptic protein (Synapsin I) expression levels did not change obviously in various brain regions. However, postsynaptic density protein 95 (PSD95) expression levels of the hippocampus and striatum in male offspring of 10.0 mg/kg LCT group, of cortex of female LCT groups, and of female offspring in all exposure groups, of striatum, in 1.0 or 10.0 mg/kg LCT exposure groups significantly decreased (P < 0.05). Early postnatal exposure to LCT affects synaptic protein expression. These effects may ultimately affect the construction of synaptic connections.

Expression of klotho mRNA and protein in rat brain parenchyma from early postnatal development into adulthood

PubMed Central

Clinton, Sarah M.; Glover, Matthew E.; Maltare, Astha; Laszczyk, Ann M.; Mehi, Stephen J.; Simmons, Rebecca K.; King, Gwendalyn D.

2013-01-01

Without the age-regulating protein klotho, mouse lifespan is shortened and the rapid onset of age-related disorders occurs. Conversely, overexpression of klotho extends mouse lifespan. Klotho is most abundant in kidney and expressed in a limited number of other organs, including the brain, where klotho levels are highest in choroid plexus. Reports vary on where klotho is expressed within the brain parenchyma, and no data is available as to whether klotho levels change across postnatal development. We used in situ hybridization to map klotho mRNA expression in the developing and adult rat brain and report moderate, widespread expression across grey matter regions. mRNA expression levels in cortex, hippocampus, caudate putamen, and amygdala decreased during the second week of life and then gradually rose to adult levels by postnatal day 21. Immunohistochemistry revealed a protein expression pattern similar to the mRNA results, with klotho protein expressed widely throughout the brain. Klotho protein co-localized with both the neuronal marker NeuN, as well as, oligodendrocyte marker olig2. These results provide the first anatomical localization of klotho mRNA and protein in rat brain parenchyma and demonstrate that klotho levels vary during early postnatal development. PMID:23838326

Development of inhibitory synaptic inputs on layer 2/3 pyramidal neurons in the rat medial prefrontal cortex.

PubMed

Virtanen, Mari A; Lacoh, Claudia Marvine; Fiumelli, Hubert; Kosel, Markus; Tyagarajan, Shiva; de Roo, Mathias; Vutskits, Laszlo

2018-05-01

Inhibitory control of pyramidal neurons plays a major role in governing the excitability in the brain. While spatial mapping of inhibitory inputs onto pyramidal neurons would provide important structural data on neuronal signaling, studying their distribution at the single cell level is difficult due to the lack of easily identifiable anatomical proxies. Here, we describe an approach where in utero electroporation of a plasmid encoding for fluorescently tagged gephyrin into the precursors of pyramidal cells along with ionotophoretic injection of Lucifer Yellow can reliably and specifically detect GABAergic synapses on the dendritic arbour of single pyramidal neurons. Using this technique and focusing on the basal dendritic arbour of layer 2/3 pyramidal cells of the medial prefrontal cortex, we demonstrate an intense development of GABAergic inputs onto these cells between postnatal days 10 and 20. While the spatial distribution of gephyrin clusters was not affected by the distance from the cell body at postnatal day 10, we found that distal dendritic segments appeared to have a higher gephyrin density at later developmental stages. We also show a transient increase around postnatal day 20 in the percentage of spines that are carrying a gephyrin cluster, indicative of innervation by a GABAergic terminal. Since the precise spatial arrangement of synaptic inputs is an important determinant of neuronal responses, we believe that the method described in this work may allow a better understanding of how inhibition settles together with excitation, and serve as basics for further modelling studies focusing on the geometry of dendritic inhibition during development.

Pyramidal tract stimulation restores normal corticospinal tract connections and visuomotor skill after early postnatal motor cortex activity blockade

PubMed Central

Salimi, I; Friel, KM; Martin, JH

2008-01-01

Motor development depends on forming specific connections between the corticospinal tract (CST) and the spinal cord. Blocking CST activity in kittens during the critical period for establishing connections with spinal motor circuits results in permanent impairments in connectivity and function. The changes in connections are consistent with the hypothesis that the inactive tract is less competitive in developing spinal connections than the active tract. In this study we tested the competition hypothesis by determining if activating CST axons, after prior silencing during the critical period, abrogated development of aberrant corticospinal connections and motor impairments. In kittens, we inactivated motor cortex by muscimol infusion between postnatal weeks 5-7. We next electrically stimulated CST axons in the medullary pyramid 2.5 hours daily, between weeks 7-10. In controls (n=3), CST terminations were densest within the contralateral deeper, premotor, spinal layers. After prior inactivation (n=3), CST terminations were densest within the dorsal, somatic sensory, layers. There were more ipsilateral terminations from the active tract. During visually guided locomotion, there was a movement endpoint impairment. Stimulation after inactivation (n=6) resulted in significantly fewer terminations in the sensory layers and more in the premotor layers, and fewer ipsilateral connections from active cortex. Chronic stimulation reduced the current threshold for evoking contralateral movements by pyramidal stimulation, suggesting strengthening of connections. Importantly, stimulation significantly improved stepping accuracy. These findings show the importance of activity-dependent processes in specifying CST connections. They also provide a strategy for harnessing activity to rescue CST axons at risk of developing aberrant connections after CNS injury. PMID:18632946

Secreted Metalloproteinase ADAMTS-3 Inactivates Reelin.

PubMed

Ogino, Himari; Hisanaga, Arisa; Kohno, Takao; Kondo, Yuta; Okumura, Kyoko; Kamei, Takana; Sato, Tempei; Asahara, Hiroshi; Tsuiji, Hitomi; Fukata, Masaki; Hattori, Mitsuharu

2017-03-22

The secreted glycoprotein Reelin regulates embryonic brain development and adult brain functions. It has been suggested that reduced Reelin activity contributes to the pathogenesis of several neuropsychiatric and neurodegenerative disorders, such as schizophrenia and Alzheimer's disease; however, noninvasive methods that can upregulate Reelin activity in vivo have yet to be developed. We previously found that the proteolytic cleavage of Reelin within Reelin repeat 3 (N-t site) abolishes Reelin activity in vitro , but it remains controversial as to whether this effect occurs in vivo Here we partially purified the enzyme that mediates the N-t cleavage of Reelin from the culture supernatant of cerebral cortical neurons. This enzyme was identified as a disintegrin and metalloproteinase with thrombospondin motifs-3 (ADAMTS-3). Recombinant ADAMTS-3 cleaved Reelin at the N-t site. ADAMTS-3 was expressed in excitatory neurons in the cerebral cortex and hippocampus. N-t cleavage of Reelin was markedly decreased in the embryonic cerebral cortex of ADAMTS-3 knock-out (KO) mice. Importantly, the amount of Dab1 and the phosphorylation level of Tau, which inversely correlate with Reelin activity, were significantly decreased in the cerebral cortex of ADAMTS-3 KO mice. Conditional KO mice, in which ADAMTS-3 was deficient only in the excitatory neurons of the forebrain, showed increased dendritic branching and elongation in the postnatal cerebral cortex. Our study shows that ADAMTS-3 is the major enzyme that cleaves and inactivates Reelin in the cerebral cortex and hippocampus. Therefore, inhibition of ADAMTS-3 may be an effective treatment for neuropsychiatric and neurodegenerative disorders. SIGNIFICANCE STATEMENT ADAMTS-3 was identified as the protease that cleaves and inactivates Reelin in the cerebral cortex and hippocampus. ADAMTS-3 was expressed in the excitatory neurons of the embryonic and postnatal cerebral cortex and hippocampus. Cleavage by ADAMTS-3 is the major contributor of Reelin inactivation in vivo Tau phosphorylation was decreased and dendritic branching and elongation was increased in ADAMTS-3-deficient mice. Therefore, inhibition of ADAMTS-3 upregulates Reelin activity and may be a potential therapeutic strategy for the prevention or treatment of neuropsychiatric and neurodegenerative disorders, such as schizophrenia and Alzheimer's disease. Copyright © 2017 the authors 0270-6474/17/373181-11$15.00/0.

In vivo gene delivery to the postnatal ferret cerebral cortex by DNA electroporation.

PubMed

Borrell, Víctor

2010-02-15

Ferrets have been extensively used to unravel the neural mechanisms of coding and processing of visual information, and also to identify the developmental mechanisms underlying the emergence of such a complex and fine-tuned neural system. In recent years numerous tools have been generated that allow studying neural systems with unprecedented power. Unfortunately, because many of these tools are genetically encoded, they are having a limited impact on research involving "non-genetic" species, like ferret, cat and monkey. Here I show how in vivo electroporation can be performed in postnatal ferret kits to deliver genetic constructs to pyramidal neurons of the cerebral cortex. Electroporation of GFP- and DsRed-encoding plasmids results in labeling of cortical progenitors first, then migrating neurons, and finally differentiating neurons and their processes. This technique also allows for the genetic manipulation of cortical development in the ferret, as illustrated by electroporation of a dominant-negative form of Cdk5. In the mature brain of electroporated animals, expression of reporter genes reveals the detailed morphological traits of cortical pyramids, including their axonal and dendritic arborization, and dendritic spines. I also show that postnatal electroporation can be used for the transfection of a massive cortical territory, or it can be specifically directed to a subset of cortical areas, and even only to a few scattered pyramids along the cortical mantle. In vivo electroporation of postnatal ferrets is therefore an effective, rapid, simple and highly versatile method for delivering genetic constructs to this animal, optimal for both developmental studies and adult anatomical/functional studies. Copyright 2009 Elsevier B.V. All rights reserved.

Selenomethionine protects against neuronal degeneration by methylmercury in the developing rat cerebrum.

PubMed

Sakamoto, Mineshi; Yasutake, Akira; Kakita, Akiyoshi; Ryufuku, Masae; Chan, Hing Man; Yamamoto, Megumi; Oumi, Sanae; Kobayashi, Sayaka; Watanabe, Chiho

2013-03-19

Although many experimental studies have shown that selenium protects against methylmercury (MeHg) toxicity at different end points, the direct interactive effects of selenium and MeHg on neurons in the brain remain unknown. Our goal is to confirm the protective effects of selenium against neuronal degeneration induced by MeHg in the developing postnatal rat brain using a postnatal rat model that is suitable for extrapolating the effects of MeHg to the fetal brain of humans. As an exposure source of selenium, we used selenomethionine (SeMet), a food-originated selenium. Wistar rats of postnatal days 14 were orally administered with vehicle (control), MeHg (8 mg Hg/kg/day), SeMet (2 mg Se/kg/day), or MeHg plus SeMet coexposure for 10 consecutive days. Neuronal degeneration and reactive astrocytosis were observed in the cerebral cortex of the MeHg-group but the symptoms were prevented by coexposure to SeMet. These findings serve as a proof that dietary selenium can directly protect neurons against MeHg toxicity in the mammalian brain, especially in the developing cerebrum.

Neurogenic Radial Glia-like Cells in Meninges Migrate and Differentiate into Functionally Integrated Neurons in the Neonatal Cortex.

PubMed

Bifari, Francesco; Decimo, Ilaria; Pino, Annachiara; Llorens-Bobadilla, Enric; Zhao, Sheng; Lange, Christian; Panuccio, Gabriella; Boeckx, Bram; Thienpont, Bernard; Vinckier, Stefan; Wyns, Sabine; Bouché, Ann; Lambrechts, Diether; Giugliano, Michele; Dewerchin, Mieke; Martin-Villalba, Ana; Carmeliet, Peter

2017-03-02

Whether new neurons are added in the postnatal cerebral cortex is still debated. Here, we report that the meninges of perinatal mice contain a population of neurogenic progenitors formed during embryonic development that migrate to the caudal cortex and differentiate into Satb2 + neurons in cortical layers II-IV. The resulting neurons are electrically functional and integrated into local microcircuits. Single-cell RNA sequencing identified meningeal cells with distinct transcriptome signatures characteristic of (1) neurogenic radial glia-like cells (resembling neural stem cells in the SVZ), (2) neuronal cells, and (3) a cell type with an intermediate phenotype, possibly representing radial glia-like meningeal cells differentiating to neuronal cells. Thus, we have identified a pool of embryonically derived radial glia-like cells present in the meninges that migrate and differentiate into functional neurons in the neonatal cerebral cortex. Copyright © 2016 Elsevier Inc. All rights reserved.

Spine Formation and Maturation in the Developing Rat Auditory Cortex

PubMed Central

Schachtele, Scott J.; Losh, Joe; Dailey, Michael E.; Green, Steven H.

2013-01-01

The rat auditory cortex is organized as a tonotopic map of sound frequency. This map is broadly tuned at birth and is refined during the first 3 weeks postnatal. The structural correlates underlying tonotopic map maturation and reorganization during development are poorly understood. We employed fluorescent dye ballistic labeling (“DiOlistics”) alone, or in conjunction with immunohistochemistry, to quantify synaptogenesis in the auditory cortex of normal hearing rats. We show that the developmental appearance of dendritic protrusions, which include both immature filopodia and mature spines, on layers 2/3, 4, and 5 pyramidal and layer 4 spiny nonpyramidal neurons occurs in three phases: slow addition of dendritic protrusions from postnatal day 4 (P4) to P9, rapid addition of dendritic protrusions from P9 to P19, and a final phase where mature protrusion density is achieved (>P21). Next, we combined DiOlistics with immunohistochemical labeling of bassoon, a presynaptic scaffolding protein, as a novel method to categorize dendritic protrusions as either filopodia or mature spines in cortex fixed in vivo. Using this method we observed an increase in the spine-to-filopodium ratio from P9–P16, indicating a period of rapid spine maturation. Previous studies report mature spines as being shorter in length compared to filopodia. We similarly observed a reduction in protrusion length between P9 and P16, corroborating our immunohistochemical spine maturation data. These studies show that dendritic protrusion formation and spine maturation occur rapidly at a time previously shown to correspond to auditory cortical tonotopic map refinement (P11–P14), providing a structural correlate of physiological maturation. PMID:21800311

Nicotinic α5 Subunits Drive Developmental Changes in the Activation and Morphology of Prefrontal Cortex Layer VI Neurons

PubMed Central

Bailey, Craig D.C.; Alves, Nyresa C.; Nashmi, Raad; De Biasi, Mariella; Lambe, Evelyn K.

2013-01-01

Background Nicotinic signaling in prefrontal layer VI pyramidal neurons is important to the function of mature attention systems. The normal incorporation of α5 subunits into α4β2* nicotinic acetylcholine receptors augments nicotinic signaling in these neurons and is required for normal attention performance in adult mice. However, the role of α5 subunits in the development of the prefrontal cortex is not known. Methods We sought to answer this question by examining nicotinic currents and neuronal morphology in layer VI neurons of medial prefrontal cortex of wild-type and α5 subunit knockout (α5−/−) mice during postnatal development and in adulthood. Results In wild-type but not in α5−/− mice, there is a developmental peak in nicotinic acetylcholine currents in the third postnatal week. At this juvenile time period, the majority of neurons in all mice have long apical dendrites extending into cortical layer I. Yet, by early adulthood, wild-type but not α5−/− mice show a pronounced shift toward shorter apical dendrites. This cellular difference occurs in the absence of genotype differences in overall cortical morphology. Conclusions Normal developmental changes in nicotinic signaling and dendritic morphology in prefrontal cortex depend on α5-comprising nicotinic acetylcholine receptors. It appears that these receptors mediate a specific developmental retraction of apical dendrites in layer VI neurons. This finding provides novel insight into the cellular mechanisms underlying the known attention deficits in α5−/− mice and potentially also into the pathophysiology of developmental neuropsychiatric disorders such as attention-deficit disorder and autism. PMID:22030359

A Sharp Cadherin-6 Gene Expression Boundary in the Developing Mouse Cortical Plate Demarcates the Future Functional Areal Border

PubMed Central

Terakawa, Youhei W.; Inoue, Yukiko U.; Asami, Junko; Hoshino, Mikio; Inoue, Takayoshi

2013-01-01

The mammalian cerebral cortex can be tangentially subdivided into tens of functional areas with distinct cyto-architectures and neural circuitries; however, it remains elusive how these areal borders are genetically elaborated during development. Here we establish original bacterial artificial chromosome transgenic mouse lines that specifically recapitulate cadherin-6 (Cdh6) mRNA expression profiles in the layer IV of the somatosensory cortex and by detailing their cortical development, we show that a sharp Cdh6 gene expression boundary is formed at a mediolateral coordinate along the cortical layer IV as early as the postnatal day 5 (P5). By further applying mouse genetics that allows rigid cell fate tracing with CreERT2 expression, it is demonstrated that the Cdh6 gene expression boundary set at around P4 eventually demarcates the areal border between the somatosensory barrel and limb field at P20. In the P6 cortical cell pellet culture system, neurons with Cdh6 expression preferentially form aggregates in a manner dependent on Ca2+ and electroporation-based Cdh6 overexpression limited to the postnatal stages perturbs area-specific cell organization in the barrel field. These results suggest that Cdh6 expression in the nascent cortical plate may serve solidification of the protomap for cortical functional areas. PMID:22875867

Developmental expression of the neuroligins and neurexins in fragile X mice.

PubMed

Lai, Jonathan K Y; Doering, Laurie C; Foster, Jane A

2016-03-01

Neuroligins and neurexins are transsynaptic proteins involved in the maturation of glutamatergic and GABAergic synapses. Research has identified synaptic proteins and function as primary contributors to the development of fragile X syndrome. Fragile X mental retardation protein (FMRP), the protein that is lacking in fragile X syndrome, binds neuroligin-1 and -3 mRNA. Using in situ hybridization, we examined temporal and spatial expression patterns of neuroligin (NLGN) and neurexin (NRXN) mRNAs in the somatosensory (S1) cortex and hippocampus in wild-type (WT) and fragile X knockout (FMR1-KO) mice during the first 5 weeks of postnatal life. Genotype-based differences in expression included increased NLGN1 mRNA in CA1 and S1 cortex, decreased NLGN2 mRNA in CA1 and dentate gyrus (DG) regions of the hippocampus, and increased NRXN3 mRNA in CA1, DG, and S1 cortex between female WT and FMR1-KO mice. In male mice, decreased expression of NRXN3 mRNA was observed in CA1 and DG regions of FMR1-KO mice. Sex differences in hippocampal expression of NLGN2, NRXN1, NRXN2, and NRXN3 mRNAs and in S1 cortex expression of NRXN3 mRNAs were observed WT mice, whereas sex differences in NLGN3, NRXN1, NRXN2, and NRXN3 mRNA expression in the hippocampus and in NLGN1, NRXN2 and NRXN3 mRNA expression in S1 cortex were detected in FMR1-KO mice. These results provide a neuroanatomical map of NLGN and NRXN expression patterns over postnatal development in WT and FMR1-KO mice. The differences in developmental trajectory of these synaptic proteins could contribute to long-term differences in CNS wiring and synaptic function. © 2015 Wiley Periodicals, Inc.

Postnatal Developmental Trajectories of Neural Circuits in the Primate Prefrontal Cortex: Identifying Sensitive Periods for Vulnerability to Schizophrenia

PubMed Central

Hoftman, Gil D.; Lewis, David A.

2011-01-01

Schizophrenia is a disorder of cognitive neurodevelopment with characteristic abnormalities in working memory attributed, at least in part, to alterations in the circuitry of the dorsolateral prefrontal cortex. Various environmental exposures from conception through adolescence increase risk for the illness, possibly by altering the developmental trajectories of prefrontal cortical circuits. Macaque monkeys provide an excellent model system for studying the maturation of prefrontal cortical circuits. Here, we review the development of glutamatergic and γ-aminobutyric acid (GABA)-ergic circuits in macaque monkey prefrontal cortex and discuss how these trajectories may help to identify sensitive periods during which environmental exposures, such as those associated with increased risk for schizophrenia, might lead to the types of abnormalities in prefrontal cortical function present in schizophrenia. PMID:21505116

Sleep contributes to dendritic spine formation and elimination in the developing mouse somatosensory cortex

PubMed Central

Yang, Guang; Gan, Wen-Biao

2012-01-01

Sleep is maximal during early postnatal life when rapid and extensive synapse remodeling occurs. It remains unknown whether and how sleep affects synapse development and plasticity. Using transcranial two-photon microscopy, we examined the formation and elimination of fluorescently-labeled dendritic spines and filopodia of layer 5 pyramidal neurons in the barrel cortex of 3-week old mice during wakefulness and sleep. We observed high turnover of dendritic protrusions over 2 hours in both wake and sleep states. The formation rate of dendritic spines or filopodia over 2 hours was comparable between the two states. The elimination rate of dendritic spines or filopodia was lower during 2-hour wakefulness than during 2-hour sleep. Similar results were observed on dendritic protrusion dynamics over 12-hour light/dark cycle when mice spent more time asleep or awake. The substantial remodeling of dendritic protrusions during the sleep state supports the notion that sleep plays an important role in the development and plasticity of synaptic connections in the mouse cortex. PMID:22058046

Vesicular glutamate transporters VGLUT1 and VGLUT2 in the developing mouse barrel cortex.

PubMed

Liguz-Lecznar, M; Skangiel-Kramska, J

2007-04-01

Three vesicular glutamate transporters have been identified in mammals. Two of them, VGLUT1 and VGLUT2, define the glutamatergic phenotype and their distribution in the brain is almost complementary. In the present study we examined the distribution and expression levels of these two VGLUTs during postnatal development of the mouse barrel cortex. We also investigated changes in the localization of VGLUT1 and VGLUT2 within particular compartments of the barrel field (barrels/septa) during its development. We found differences in the time course of developmental expression, with VGLUT1 peaking around P14, while VGLUT2 increased gradually until adulthood. Over the examined period (P3 - adult) both transporters had stronger expression in the barrel interiors, and in this compartment VGLUT2 dominated, whereas in the inter-barrel septa VGLUT1 dominated over VGLUT2. Furthermore, we found that some nerve terminals in the barrel cortex coexpressed both transporters until adulthood. Colocalization was observed within the barrels, but not within the septa.

Postnatal Changes in the Distribution of Acetylcholinesterase in Kitten Visual Cortex.

DTIC Science & Technology

1985-02-18

in cat striate cortex. However, a subpopulation of stained neurons appers in layer V by one year of age that persists into adulthood. The possible...next two months until, at three months of age, ! ’ there are no AChE-positive cells in cat striate cortex. However, a subpopulation of stained...undertake a systematic investigation of cholinergic inputs to area 17 in the cat . 4 4: • ." "k

Prox1 Regulates the Subtype-Specific Development of Caudal Ganglionic Eminence-Derived GABAergic Cortical Interneurons

PubMed Central

Young, Allison; Petros, Timothy; Karayannis, Theofanis; McKenzie Chang, Melissa; Lavado, Alfonso; Iwano, Tomohiko; Nakajima, Miho; Taniguchi, Hiroki; Huang, Z. Josh; Heintz, Nathaniel; Oliver, Guillermo; Matsuzaki, Fumio; Machold, Robert P.

2015-01-01

Neurogliaform (RELN+) and bipolar (VIP+) GABAergic interneurons of the mammalian cerebral cortex provide critical inhibition locally within the superficial layers. While these subtypes are known to originate from the embryonic caudal ganglionic eminence (CGE), the specific genetic programs that direct their positioning, maturation, and integration into the cortical network have not been elucidated. Here, we report that in mice expression of the transcription factor Prox1 is selectively maintained in postmitotic CGE-derived cortical interneuron precursors and that loss of Prox1 impairs the integration of these cells into superficial layers. Moreover, Prox1 differentially regulates the postnatal maturation of each specific subtype originating from the CGE (RELN, Calb2/VIP, and VIP). Interestingly, Prox1 promotes the maturation of CGE-derived interneuron subtypes through intrinsic differentiation programs that operate in tandem with extrinsically driven neuronal activity-dependent pathways. Thus Prox1 represents the first identified transcription factor specifically required for the embryonic and postnatal acquisition of CGE-derived cortical interneuron properties. SIGNIFICANCE STATEMENT Despite the recognition that 30% of GABAergic cortical interneurons originate from the caudal ganglionic eminence (CGE), to date, a specific transcriptional program that selectively regulates the development of these populations has not yet been identified. Moreover, while CGE-derived interneurons display unique patterns of tangential and radial migration and preferentially populate the superficial layers of the cortex, identification of a molecular program that controls these events is lacking. Here, we demonstrate that the homeodomain transcription factor Prox1 is expressed in postmitotic CGE-derived cortical interneuron precursors and is maintained into adulthood. We found that Prox1 function is differentially required during both embryonic and postnatal stages of development to direct the migration, differentiation, circuit integration, and maintenance programs within distinct subtypes of CGE-derived interneurons. PMID:26377473

Down-regulation of sup 3 H-imipramine binding sites in rat cerebral cortex prenatal exposure to antidepressants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Montero, D.; de Ceballos, M.L.; Del Rio, J.

1990-01-01

Several antidepressant drugs were given to pregnant rats in the last 15 days of gestation and {sup 3}H-imipramine binding ({sup 3}H-IMI) was subsequently measured in the cerebral cortex of the offspring. The selective serotonin (5-HT) uptake blockers chlorimipramine and fluoxetine as well as the selective monoamine oxidase (MAO) inhibitors clorgyline and deprenyl induced, after prenatal exposure, a down-regulation of {sup 3}H-IMI binding sites at postnatal day 25. The density of these binding sites was still reduced at postnatal day 90 in rats exposed in utero to the MAO inhibitors. The antidepressants desipramine and nomifensine were ineffective in this respect. Aftermore » chronic treatment of adult animals, only chlorimipramine was able to down-regulate the {sup 3}H-IMI binding sites. Consequently, prenatal exposure of rats to different antidepressant drugs affecting predominantly the 5-HT systems induces more marked and long-lasting effects on cortical {sup 3}H-IMI binding sites. The results suggest that the developing brain is more susceptible to the actions of antidepressants.« less

Experience and the developing prefrontal cortex

PubMed Central

Kolb, Bryan; Mychasiuk, Richelle; Muhammad, Arif; Li, Yilin; Frost, Douglas O.; Gibb, Robbin

2012-01-01

The prefrontal cortex (PFC) receives input from all other cortical regions and functions to plan and direct motor, cognitive, affective, and social behavior across time. It has a prolonged development, which allows the acquisition of complex cognitive abilities through experience but makes it susceptible to factors that can lead to abnormal functioning, which is often manifested in neuropsychiatric disorders. When the PFC is exposed to different environmental events during development, such as sensory stimuli, stress, drugs, hormones, and social experiences (including both parental and peer interactions), the developing PFC may develop in different ways. The goal of the current review is to illustrate how the circuitry of the developing PFC can be sculpted by a wide range of pre- and postnatal factors. We begin with an overview of prefrontal functioning and development, and we conclude with a consideration of how early experiences influence prefrontal development and behavior. PMID:23045653

Morphological, structural, and functional alterations of the prefrontal cortex and the basolateral amygdala after early lesion of the rat mediodorsal thalamus.

PubMed

Ouhaz, Zakaria; Ba-M'hamed, Saadia; Bennis, Mohamed

2017-08-01

Early postnatal damage to the mediodorsal thalamus (MD) produces deficits in cognition and behavior believed to be associated with early prefrontal cortical maldevelopment. We assessed the role of MD afferents during development on the morphological and functional maturation of the prefrontal cortex (PFC) and the basolateral amygdala (BLA). Sprague-Dawley rat pups (n = 56) received a bilateral electrolytic lesion of the MD or a MD Sham lesion on postnatal day 4. 7 weeks later, all rats were tested in anxiety-related and cognitive paradigms using the elevated plus maze and novel object recognition tests. Following behavioral testing (P70), rats were killed and the baseline expression of C-Fos protein and the number of GABAergic neurons were evaluated in the PFC and the BLA. The dendritic morphology and spine density in the PFC using Golgi-Cox staining was also evaluated. Adult rats with early postnatal bilateral MD damage exhibited disrupted recognition memory and increased anxiety-like behaviors. The lesion also caused a significant diminution of C-Fos immunolabeling and an increase of the number of GABAergic neurons in the PFC. In the BLA, the number of GABAergic neurons was significantly reduced, associated with an increase in C-Fos immunolabeling. Furthermore, in the PFC the lesion induced a significant reduction in dendritic branching and spine density. Our data are consistent with the hypothesis that the MD plays a role in the development of the PFC and, therefore, may be a good animal model to investigate cognitive symptoms associated with schizophrenia.

Longitudinal 1H MR spectroscopy of rat forebrain from infancy to adulthood reveals adolescence as a distinctive phase of neurometabolite development

PubMed Central

Morgan, Jonathan J.; Kleven, Gale A.; Tulbert, Christina D.; Olson, John; Horita, David A.; Ronca, April E.

2013-01-01

The present study represents the first longitudinal, within-subject 1H MRS investigation of the developing rat brain spanning infancy, adolescence, and early adulthood. We obtained neurometabolite profiles from a voxel located in a central location of the forebrain, centered on the striatum, with smaller contributions for cortex, thalamus, and hypothalamus, on postnatal days 7, 35, and 60. Water-scaled metabolite signals were corrected for T1 effects and quantified using the automated processing software LCModel, yielding molal concentrations. Our findings indicate age-related concentration changes in N-acetylaspartate + N-acetylaspartylglutamate, myo-inositol, glutamate + glutamine, taurine, creatine + phosphocreatine, and glycerophosphocholine + phosphocholine. Using a repeated measures design and analysis, we identified significant neurodevelopment change across all three developmental ages and identified adolescence as a distinctive phase in normative neurometabolic brain development. Between postnatal days 35 and 60, changes were observed in concentrations of N-acetylaspartate + N-acetylaspartylglutamate, glutamate + glutamine, and glycerophosphocholine + phosphocholine observed between postnatal days 35 and 60. Our data replicate past studies of early neurometabolite development and, for the first time, link maturational profiles in the same subjects across infancy, adolescence, and adulthood. PMID:23322706

Identification of α-Chimaerin as a Candidate Gene for Critical Period Neuronal Plasticity in Cat and Mouse Visual Cortex

PubMed Central

2011-01-01

Background In cat visual cortex, critical period neuronal plasticity is minimal until approximately 3 postnatal weeks, peaks at 5 weeks, gradually declines to low levels at 20 weeks, and disappears by 1 year of age. Dark rearing slows the entire time course of this critical period, such that at 5 weeks of age, normal cats are more plastic than dark reared cats, whereas at 20 weeks, dark reared cats are more plastic. Thus, a stringent criterion for identifying genes that are important for plasticity in visual cortex is that they show differences in expression between normal and dark reared that are of opposite direction in young versus older animals. Results The present study reports the identification by differential display PCR of a novel gene, α-chimaerin, as a candidate visual cortex critical period plasticity gene that showed bidirectional regulation of expression due to age and dark rearing. Northern blotting confirmed the bidirectional expression and 5'RACE sequencing identified the gene. There are two alternatively-spliced α-chimaerin isoforms: α1 and α2. Western blotting extended the evidence for bidirectional regulation of visual cortex α-chimaerin isoform expression to protein in cats and mice. α1- and α2-Chimaerin were elevated in dark reared compared to normal visual cortex at the peak of the normal critical period and in normal compared to dark reared visual cortex at the nadir of the normal critical period. Analysis of variance showed a significant interaction in both cats and mice for both α-chimaerin isoforms, indicating that the effect of dark rearing depended on age. This differential expression was not found in frontal cortex. Conclusions Chimaerins are RhoGTPase-activating proteins that are EphA4 effectors and have been implicated in a number of processes including growth cone collapse, axon guidance, dendritic spine development and the formation of corticospinal motor circuits. The present results identify α-chimaerin as a candidate molecule for a role in the postnatal critical period of visual cortical plasticity. PMID:21767388

Pre- and post-natal melatonin administration partially regulates brain oxidative stress but does not improve cognitive or histological alterations in the Ts65Dn mouse model of Down syndrome.

PubMed

Corrales, Andrea; Parisotto, Eduardo B; Vidal, Verónica; García-Cerro, Susana; Lantigua, Sara; Diego, Marian; Wilhem Filho, Danilo; Sanchez-Barceló, Emilio J; Martínez-Cué, Carmen; Rueda, Noemí

2017-09-15

Melatonin administered during adulthood induces beneficial effects on cognition and neuroprotection in the Ts65Dn (TS) mouse model of Down syndrome. Here, we investigated the effects of pre- and post-natal melatonin treatment on behavioral and cognitive abnormalities and on several neuromorphological alterations (hypocellularity, neurogenesis impairment and increased oxidative stress) that appear during the early developmental stages in TS mice. Pregnant TS females were orally treated with melatonin or vehicle from the time of conception until the weaning of the offspring, and the pups continued to receive the treatment from weaning until the age of 5 months. Melatonin administered during the pre- and post-natal periods did not improve the cognitive impairment of TS mice as measured by the Morris Water maze or fear conditioning tests. Histological alterations, such as decreased proliferation (Ki67+ cells) and hippocampal hypocellularity (DAPI+ cells), which are typical in TS mice, were not prevented by melatonin. However, melatonin partially regulated brain oxidative stress by modulating the activity of the primary antioxidant enzymes (superoxide dismutase in the cortex and catalase in the cortex and hippocampus) and slightly decreasing the levels of lipid peroxidation in the hippocampus of TS mice. These results show the inability of melatonin to prevent cognitive impairment in TS mice when it is administered at pre- and post-natal stages. Additionally, our findings suggest that to induce pro-cognitive effects in TS mice during the early stages of development, in addition to attenuating oxidative stress, therapies should aim to improve other altered processes, such as hippocampal neurogenesis and/or hypocellularity. Copyright © 2017 Elsevier B.V. All rights reserved.

Prenatal exposure to an NMDA receptor antagonist, MK-801 reduces density of parvalbumin-immunoreactive GABAergic neurons in the medial prefrontal cortex and enhances phencyclidine-induced hyperlocomotion but not behavioral sensitization to methamphetamine in postpubertal rats.

PubMed

Abekawa, Tomohiro; Ito, Koki; Nakagawa, Shin; Koyama, Tsukasa

2007-06-01

Neurodevelopmental deficits of parvalbumin-immunoreactive gamma-aminobutyric acid (GABA)ergic interneurons in prefrontal cortex have been reported in schizophrenia. Glutamate influences the proliferation of this type of interneuron by an N-methyl-D-aspartate (NMDA)-receptor-mediated mechanism. The present study hypothesized that prenatal blockade of NMDA receptors would disrupt GABAergic neurodevelopment, resulting in differences in effects on behavioral responses to a noncompetitive NMDA antagonist, phencyclidine (PCP), and a dopamine releaser, methamphetamine (METH). GABAergic neurons were immunohistochemically stained with parvalbumin antibody. Psychostimulant-induced hyperlocomotion was measured using an infrared sensor. Prenatal exposure (E15-E18) to the NMDA receptor antagonist MK-801 reduced the density of parvalbumin-immunoreactive neurons in rat medial prefrontal cortex on postnatal day 63 (P63) and enhanced PCP-induced hyperlocomotion but not the acute effects of METH on P63 or the development of behavioral sensitization. Prenatal exposure to MK-801 reduced the number of parvalbumin-immunoreactive neurons even on postnatal day 35 (P35) and did not enhance PCP-induced hyperlocomotion, the acute effects of METH on P35, or the development of behavioral sensitization to METH. These findings suggest that prenatal blockade of NMDA receptors disrupts GABAergic neurodevelopment in medial prefrontal cortex, and that this disruption of GABAergic development may be related to the enhancement of the locomotion-inducing effect of PCP in postpubertal but not juvenile offspring. GABAergic deficit is unrelated to the effects of METH. This GABAergic neurodevelopmental disruption and the enhanced PCP-induced hyperlocomotion in adult offspring prenatally exposed to MK-801 may prove useful as a new model of the neurodevelopmental process of pathogenesis of treatment-resistant schizophrenia via an NMDA-receptor-mediated hypoglutamatergic mechanism.

Asymmetrical Interhemispheric Connections Develop in Cat Visual Cortex after Early Unilateral Convergent Strabismus: Anatomy, Physiology, and Mechanisms

PubMed Central

Bui Quoc, Emmanuel; Ribot, Jérôme; Quenech’Du, Nicole; Doutremer, Suzette; Lebas, Nicolas; Grantyn, Alexej; Aushana, Yonane; Milleret, Chantal

2011-01-01

In the mammalian primary visual cortex, the corpus callosum contributes to the unification of the visual hemifields that project to the two hemispheres. Its development depends on visual experience. When this is abnormal, callosal connections must undergo dramatic anatomical and physiological changes. However, data concerning these changes are sparse and incomplete. Thus, little is known about the impact of abnormal postnatal visual experience on the development of callosal connections and their role in unifying representation of the two hemifields. Here, the effects of early unilateral convergent strabismus (a model of abnormal visual experience) were fully characterized with respect to the development of the callosal connections in cat visual cortex, an experimental model for humans. Electrophysiological responses and 3D reconstruction of single callosal axons show that abnormally asymmetrical callosal connections develop after unilateral convergent strabismus, resulting from an extension of axonal branches of specific orders in the hemisphere ipsilateral to the deviated eye and a decreased number of nodes and terminals in the other (ipsilateral to the non-deviated eye). Furthermore this asymmetrical organization prevents the establishment of a unifying representation of the two visual hemifields. As a general rule, we suggest that crossed and uncrossed retino-geniculo-cortical pathways contribute successively to the development of the callosal maps in visual cortex. PMID:22275883

Endogenous GFAP-Positive Neural Stem/Progenitor Cells in the Postnatal Mouse Cortex Are Activated following Traumatic Brain Injury

PubMed Central

Ahmed, Aminul I.; Shtaya, Anan B.; Zaben, Malik J.; Owens, Emma V.; Kiecker, Clemens

2012-01-01

Abstract Interest in promoting regeneration of the injured nervous system has recently turned toward the use of endogenous stem cells. Elucidating cues involved in driving these precursor cells out of quiescence following injury, and the signals that drive them toward neuronal and glial lineages, will help to harness these cells for repair. Using a biomechanically validated in vitro organotypic stretch injury model, cortico-hippocampal slices from postnatal mice were cultured and a stretch injury equivalent to a severe traumatic brain injury (TBI) applied. In uninjured cortex, proliferative potential under in vitro conditions is virtually absent in older slices (equivalent postnatal day 15 compared to 8). However, following a severe stretch injury, this potential is restored in injured outer cortex. Using slices from mice expressing a fluorescent reporter on the human glial fibrillary acidic protein (GFAP) promoter, we show that GFAP+ cells account for the majority of proliferating neurospheres formed, and that these cells are likely to arise from the cortical parenchyma and not from the subventricular zone. Moreover, we provide evidence for a correlation between upregulation of sonic hedgehog signaling, a pathway known to regulate stem cell proliferation, and this restoration of regenerative potential following TBI. Our results indicate that a source of quiescent endogenous stem cells residing in the cortex and subcortical tissue proliferate in vitro following TBI. Moreover, these proliferating cells are multipotent and are derived mostly from GFAP-expressing cells. This raises the possibility of using this endogenous source of stem cells for repair following TBI. PMID:21895532

From retinal waves to activity-dependent retinogeniculate map development.

PubMed

Markowitz, Jeffrey; Cao, Yongqiang; Grossberg, Stephen

2012-01-01

A neural model is described of how spontaneous retinal waves are formed in infant mammals, and how these waves organize activity-dependent development of a topographic map in the lateral geniculate nucleus, with connections from each eye segregated into separate anatomical layers. The model simulates the spontaneous behavior of starburst amacrine cells and retinal ganglion cells during the production of retinal waves during the first few weeks of mammalian postnatal development. It proposes how excitatory and inhibitory mechanisms within individual cells, such as Ca(2+)-activated K(+) channels, and cAMP currents and signaling cascades, can modulate the spatiotemporal dynamics of waves, notably by controlling the after-hyperpolarization currents of starburst amacrine cells. Given the critical role of the geniculate map in the development of visual cortex, these results provide a foundation for analyzing the temporal dynamics whereby the visual cortex itself develops.

Hypothalamic-Pituitary-Adrenal Axis Programming after Recurrent Hypoglycemia during Development

PubMed Central

Rao, Raghavendra

2015-01-01

Permanent brain injury is a complication of recurrent hypoglycemia during development. Recurrent hypoglycemia also has adverse consequences on the neuroendocrine system. Hypoglycemia-associated autonomic failure, characterized by ineffective glucose counterregulation during hypoglycemia, is well described in children and adults on insulin therapy for diabetes mellitus. Whether recurrent hypoglycemia also has a programming effect on the hypothalamus-pituitary-adrenal cortex (HPA) axis has not been well studied. Hypoglycemia is a potent stress that leads to increased glucocorticoid secretion in all age groups, including the perinatal period. Other conditions associated with exposure to excess glucocorticoid in the perinatal period have a programming effect on the HPA axis activity. Limited animal data suggest the possibility of similar programming effect after recurrent hypoglycemia in the postnatal period. The age at exposure to hypoglycemia likely determines the HPA axis response in adulthood. Recurrent hypoglycemia in the early postnatal period likely leads to a hyperresponsive HPA axis, whereas recurrent hypoglycemia in the late postnatal period lead to a hyporesponsive HPA axis in adulthood. The age-specific programming effects may determine the neuroendocrine response during hypoglycemia and other stressful events in individuals with history of recurrent hypoglycemia during development. PMID:26343738

Hypothalamic-Pituitary-Adrenal Axis Programming after Recurrent Hypoglycemia during Development.

PubMed

Rao, Raghavendra

2015-08-28

Permanent brain injury is a complication of recurrent hypoglycemia during development. Recurrent hypoglycemia also has adverse consequences on the neuroendocrine system. Hypoglycemia-associated autonomic failure, characterized by ineffective glucose counterregulation during hypoglycemia, is well described in children and adults on insulin therapy for diabetes mellitus. Whether recurrent hypoglycemia also has a programming effect on the hypothalamus-pituitary-adrenal cortex (HPA) axis has not been well studied. Hypoglycemia is a potent stress that leads to increased glucocorticoid secretion in all age groups, including the perinatal period. Other conditions associated with exposure to excess glucocorticoid in the perinatal period have a programming effect on the HPA axis activity. Limited animal data suggest the possibility of similar programming effect after recurrent hypoglycemia in the postnatal period. The age at exposure to hypoglycemia likely determines the HPA axis response in adulthood. Recurrent hypoglycemia in the early postnatal period likely leads to a hyperresponsive HPA axis, whereas recurrent hypoglycemia in the late postnatal period lead to a hyporesponsive HPA axis in adulthood. The age-specific programming effects may determine the neuroendocrine response during hypoglycemia and other stressful events in individuals with history of recurrent hypoglycemia during development.

Bilateral Activity-Dependent Interactions in the Developing Corticospinal System

PubMed Central

Friel, Kathleen M.; Martin, John H.

2009-01-01

Activity-dependent competition between the corticospinal (CS) systems in each hemisphere drives postnatal development of motor skills and stable CS tract connections with contralateral spinal motor circuits. Unilateral restriction of motor cortex (M1) activity during an early postnatal critical period impairs contralateral visually guided movements later in development and in maturity. Silenced M1 develops aberrant connections with the contralateral spinal cord whereas the initially active M1, in the other hemisphere, develops bilateral connections. In this study, we determined whether the aberrant pattern of CS tract terminations and motor impairments produced by early postnatal M1 activity restriction could be abrogated by reducing activity-dependent synaptic competition from the initially active M1 later in development. We first inactivated M1 unilaterally between postnatal weeks 5–7. We next inactivated M1 on the other side from weeks 7–11 (alternate inactivation), to reduce the competitive advantage that this side may have over the initially inactivated side. Alternate inactivation redirected aberrant contralateral CS tract terminations from the initially silenced M1 to their normal spinal territories and reduced the density of aberrant ipsilateral terminations from the initially active side. Normal movement endpoint control during visually guided locomotion was fully restored. This reorganization of CS terminals reveals an unsuspected late plasticity after the critical period for establishing the pattern of CS terminations in the spinal cord. Our findings show that robust bilateral interactions between the developing CS systems on each side are important for achieving balance between contralateral and ipsilateral CS tract connections and visuomotor control. PMID:17928450

Extrinsic Embryonic Sensory Stimulation Alters Multimodal Behavior and Cellular Activation

PubMed Central

Markham, Rebecca G.; Shimizu, Toru; Lickliter, Robert

2009-01-01

Embryonic vision is generated and maintained by spontaneous neuronal activation patterns, yet extrinsic stimulation also sculpts sensory development. Because the sensory and motor systems are interconnected in embryogenesis, how extrinsic sensory activation guides multimodal differentiation is an important topic. Further, it is unknown whether extrinsic stimulation experienced near sensory sensitivity onset contributes to persistent brain changes, ultimately affecting postnatal behavior. To determine the effects of extrinsic stimulation on multimodal development, we delivered auditory stimulation to bobwhite quail groups during early, middle, or late embryogenesis, and then tested postnatal behavioral responsiveness to auditory or visual cues. Auditory preference tendencies were more consistently toward the conspecific stimulus for animals stimulated during late embryogenesis. Groups stimulated during middle or late embryogenesis showed altered postnatal species-typical visual responsiveness, demonstrating a persistent multimodal effect. We also examined whether auditory-related brain regions are receptive to extrinsic input during middle embryogenesis by measuring postnatal cellular activation. Stimulated birds showed a greater number of ZENK-immunopositive cells per unit volume of brain tissue in deep optic tectum, a midbrain region strongly implicated in multimodal function. We observed similar results in the medial and caudomedial nidopallia in the telencephalon. There were no ZENK differences between groups in inferior colliculus or in caudolateral nidopallium, avian analog to prefrontal cortex. To our knowledge, these are the first results linking extrinsic stimulation delivered so early in embryogenesis to changes in postnatal multimodal behavior and cellular activation. The potential role of competitive interactions between the sensory and motor systems is discussed. PMID:18777564

Amelioration of cerebellar dysfunction in rats following postnatal ethanol exposure using low-intensity pulsed ultrasound.

PubMed

Bolbanabad, Hiva Mohammadi; Anvari, Enayat; Rezai, Mohammad Jafar; Moayeri, Ardashir; Kaffashian, Mohammad Reza

2017-04-01

The neonatal development stage of the cerebellum in rats is equivalent to a human foetus in the third trimester of pregnancy. In this stage, cell proliferation, migration, differentiation, and synaptogenesis occur. Clinical and experimental findings have shown that ethanol exposure during brain development causes a variety of disruptions to the brain, including neurogenesis depression, delayed neuronal migration, changes in neurotransmitter synthesis, and neuronal depletion.During postnatal cerebellar development, neurons are more vulnerable to the destructive effects of ethanol. The effects of low-intensity pulsed ultrasound (LIPUS) on the number of cells and thickness of the cell layers within the cerebellar cortex were examined during the first two postnatal weeks in rats following postnatal ethanol exposure. Postpartum rats were distributed randomly into six groups. Normal saline was injected intraperitoneally into control animals and ethanol (20%) was injected into the intervention groups for three consecutive days. Intervention groups received LIPUS at different frequencies (3 or 5MHz), after administration of ethanol. After transcardial perfusion, the rat's brain was removed, and a complete series of sagittal cerebellum sections were obtained by systematic random manner. Photomicrographs were made with Motic digital cameras and analysed using Nikon digital software. The numbers of granular cells decreased in ethanol-treated rats compared to the control group. LIPUS, administered at (3 or 5MHz), combined with ethanol administration resulted in a reduction of ethanol's effects. Using 5MHz LIPUS resulted in significantly higher numbers of granular cells in the internal layer compared to the control rats. Using 3 or 5MHz LIPUS alone resulted in a significant enhancement in the granular cells of the molecular layer. A significant reduction was seen in the thickness of the external granular layer in ethanol-treated rats. This study showed that exposure to LIPUS can affect the number of granular cells and thickness of the cell layer within the cerebellar cortex in neonatal rats. LIPUS also could attenuate ethanol toxicity effects on the cerebellum. Copyright © 2017 Elsevier B.V. All rights reserved.

Late emergence of the vibrissa direction selectivity map in the rat barrel cortex.

PubMed

Kremer, Yves; Léger, Jean-François; Goodman, Dan; Brette, Romain; Bourdieu, Laurent

2011-07-20

In the neocortex, neuronal selectivities for multiple sensorimotor modalities are often distributed in topographical maps thought to emerge during a restricted period in early postnatal development. Rodent barrel cortex contains a somatotopic map for vibrissa identity, but the existence of maps representing other tactile features has not been clearly demonstrated. We addressed the issue of the existence in the rat cortex of an intrabarrel map for vibrissa movement direction using in vivo two-photon imaging. We discovered that the emergence of a direction map in rat barrel cortex occurs long after all known critical periods in the somatosensory system. This map is remarkably specific, taking a pinwheel-like form centered near the barrel center and aligned to the barrel cortex somatotopy. We suggest that this map may arise from intracortical mechanisms and demonstrate by simulation that the combination of spike-timing-dependent plasticity at synapses between layer 4 and layer 2/3 and realistic pad stimulation is sufficient to produce such a map. Its late emergence long after other classical maps suggests that experience-dependent map formation and refinement continue throughout adult life.

Expression of APG-2 protein, a member of the heat shock protein 110 family, in developing rat brain.

PubMed

Okui, M; Ito, F; Ogita, K; Kuramoto, N; Kudoh, J; Shimizu, N; Ide, T

2000-01-01

APG-2 protein is a member of the heat shock protein 110 family, and it is thought to play an important role in the maintenance of neuronal functions under physiological and stress conditions. However, neither the tissue-distribution of APG-2 protein nor developmental change of its expression has been studied at the protein level. Therefore, we generated an antiserum against APG-2 protein and studied expression of this protein in rat brain and other tissues by use of the Western blot method. The results showed a high expression of APG-2 protein in various regions of the central nervous system (cerebral cortex, hippocampus, striatum, midbrain, hypothalamus, cerebellum, medulla pons, and spinal cord) throughout the entire postnatal stage. Similarly, a high level of APG-2 protein was detected in the whole brain of rat embryos and in adult rat tissues such as liver, lung, spleen, and kidney. In contrast, its expression in heart was high at postnatal days 1 and 3, but thereafter drastically decreased to a low level. Furthermore, APG-2 protein was detected in neuronal primary cultures prepared from rat cerebral cortex, and its level did not change notably during neuronal differentiation. These results show that APG-2 protein is constitutively expressed in various tissues and also in neuronal cells throughout the entire embryonic and postnatal period. suggesting that it might play an important role in these tissues under non-stress conditions.

Electrical activity controls area-specific expression of neuronal apoptosis in the mouse developing cerebral cortex.

PubMed

Blanquie, Oriane; Yang, Jenq-Wei; Kilb, Werner; Sharopov, Salim; Sinning, Anne; Luhmann, Heiko J

2017-08-21

Programmed cell death widely but heterogeneously affects the developing brain, causing the loss of up to 50% of neurons in rodents. However, whether this heterogeneity originates from neuronal identity and/or network-dependent processes is unknown. Here, we report that the primary motor cortex (M1) and primary somatosensory cortex (S1), two adjacent but functionally distinct areas, display striking differences in density of apoptotic neurons during the early postnatal period. These differences in rate of apoptosis negatively correlate with region-dependent levels of activity. Disrupting this activity either pharmacologically or by electrical stimulation alters the spatial pattern of apoptosis and sensory deprivation leads to exacerbated amounts of apoptotic neurons in the corresponding functional area of the neocortex. Thus, our data demonstrate that spontaneous and periphery-driven activity patterns are important for the structural and functional maturation of the neocortex by refining the final number of cortical neurons in a region-dependent manner.

Differential Regulation of the Ascorbic Acid Transporter SVCT2 during Development and in Response to Ascorbic Acid Depletion

PubMed Central

Meredith, M. Elizabeth; Harrison, Fiona E.; May, James M.

2011-01-01

The sodium-dependent vitamin C transporter-2 (SVCT2) is the only ascorbic acid (ASC) transporter significantly expressed in brain. It is required for life and critical during brain development to supply adequate levels of ASC. To assess SVCT2 function in the developing brain, we studied time-dependent SVCT2 mRNA and protein expression in mouse brain, using liver as a comparison tissue because it is the site of ASC synthesis. We found that SVCT2 expression followed an inverse relationship with ASC levels in the developing brain. In cortex and cerebellum, ASC levels were high throughout late embryonic stages and early post-natal stages and decreased with age, whereas SVCT2 mRNA and protein levels were low in embryos and increased with age. A different response was observed for liver, in which ASC levels and SVCT2 expression were both low throughout embryogenesis and increased post-natally. To determine whether low intracellular ASC might be capable of driving SVCT2 expression, we depleted ASC by diet in adult mice unable to synthesize ASC. We observed that SVCT2 mRNA and protein were not affected by ASC depletion in brain cortex, but SVCT2 protein expression was increased by ASC depletion in the cerebellum and liver. The results suggest that expression of the SVCT2 is differentially regulated during embryonic development and in adulthood. PMID:22001929

Methamidophos Exposure During the Early Postnatal Period of Mice: Immediate and Late-Emergent Effects on the Cholinergic and Serotonergic Systems and Behavior

PubMed Central

Abreu-Villaça, Yael

2013-01-01

Organophosphates (OPs) are among the most used pesticides. Although some OPs have had their use progressively more restricted, other OPs are being used without sufficient investigation of their effects. Here, we investigated the immediate neurochemical and delayed neurochemical and behavioral actions of the OP methamidophos to verify whether there are concerns regarding exposure during early postnatal development. From the third to the nineth postnatal day (PN), Swiss mice were sc injected with methamidophos (1mg/kg). At PN10, we assessed cholinergic and serotonergic biomarkers in the cerebral cortex and brainstem. From PN60 to PN63, mice were submitted to a battery of behavioral tests and subsequently to biochemical analyses. At PN10, the effects were restricted to females and to the cholinergic system: Methamidophos promoted increased choline transporter binding in the brainstem. At PN63, in the brainstem, there was a decrease in choline transporter, a female-only decrease in 5HT1A and a male-only increase in 5HT2 receptor binding. In the cortex, choline acetyltransferase activity was decreased and 5HT2 receptor binding was increased both in males and females. Methamidophos elicited behavioral alterations, suggestive of increased depressive-like behavior and impaired decision making. There were no significant alterations on anxiety-related measures and on memory/learning. Methamidophos elicited cholinergic and serotonergic alterations that depended on brain region, sex, and age of the animals. These outcomes, together with the behavioral effects, indicate that this OP is deleterious to the developing brain and that alterations are indeed identified long after the end of exposure. PMID:23596261

Methamidophos exposure during the early postnatal period of mice: immediate and late-emergent effects on the cholinergic and serotonergic systems and behavior.

PubMed

Lima, Carla S; Dutra-Tavares, Ana C; Nunes, Fernanda; Nunes-Freitas, André L; Ribeiro-Carvalho, Anderson; Filgueiras, Cláudio C; Manhães, Alex C; Meyer, Armando; Abreu-Villaça, Yael

2013-07-01

Organophosphates (OPs) are among the most used pesticides. Although some OPs have had their use progressively more restricted, other OPs are being used without sufficient investigation of their effects. Here, we investigated the immediate neurochemical and delayed neurochemical and behavioral actions of the OP methamidophos to verify whether there are concerns regarding exposure during early postnatal development. From the third to the nineth postnatal day (PN), Swiss mice were sc injected with methamidophos (1mg/kg). At PN10, we assessed cholinergic and serotonergic biomarkers in the cerebral cortex and brainstem. From PN60 to PN63, mice were submitted to a battery of behavioral tests and subsequently to biochemical analyses. At PN10, the effects were restricted to females and to the cholinergic system: Methamidophos promoted increased choline transporter binding in the brainstem. At PN63, in the brainstem, there was a decrease in choline transporter, a female-only decrease in 5HT1A and a male-only increase in 5HT2 receptor binding. In the cortex, choline acetyltransferase activity was decreased and 5HT2 receptor binding was increased both in males and females. Methamidophos elicited behavioral alterations, suggestive of increased depressive-like behavior and impaired decision making. There were no significant alterations on anxiety-related measures and on memory/learning. Methamidophos elicited cholinergic and serotonergic alterations that depended on brain region, sex, and age of the animals. These outcomes, together with the behavioral effects, indicate that this OP is deleterious to the developing brain and that alterations are indeed identified long after the end of exposure.

Late emerging effects of prenatal and early postnatal nicotine exposure on the cholinergic system and anxiety-like behavior.

PubMed

Eppolito, Amy K; Bachus, Susan E; McDonald, Craig G; Meador-Woodruff, James H; Smith, Robert F

2010-01-01

Animal models of prenatal nicotine exposure clearly indicate that nicotine is a neuroteratogen. Some of the persisting effects of prenatal nicotine exposure include low birth weight, behavioral changes and deficits in cognitive function, although few studies have looked for neurobehavioral and neurochemical effects that might persist throughout the lifespan. Pregnant rats were given continuous infusions of nicotine (0.96mg/kg/day or 2.0mg/kg/day, freebase) continuing through the third trimester equivalent, a period of rapid brain development. Because the third trimester equivalent occurs postnatally in the rat (roughly the first week of life) nicotine administration to neonate pups continued via maternal milk until postnatal day (P) 10. Exposure to nicotine during pre- and early postnatal development had an anxiogenic effect on adult rats (P75) in the elevated plus maze (EPM), and blocked extinction learning in a fear conditioning paradigm, suggesting that pre- and postnatal nicotine exposure affect anxiety-like behavior and cognitive function well into adulthood. In contrast, nicotine exposure had no effect on anxiety-like behaviors in the EPM in adolescent animals (P30). Analysis of mRNA for the alpha4, alpha7, and beta2 subunits of nicotinic acetylcholine receptors revealed lower expression of these subunits in the adult hippocampus and medial prefrontal cortex following pre- and postnatal nicotine exposure, suggesting that nicotine altered the developmental trajectory of the brain. These long-term behavioral and neurochemical changes strengthen the case for discouraging cigarette smoking during pregnancy and clearly indicate that the use of the patch as a smoking cessation aid during pregnancy is not a safe alternative.

Experience-dependent development of perineuronal nets and chondroitin sulfate proteoglycan receptors in mouse visual cortex.

PubMed

Ye, Qian; Miao, Qing-Long

2013-08-08

Perineuronal nets (PNNs) are extracellular matrix structures consisting of chondroitin sulfate proteoglycans (CSPGs), hyaluronan, link proteins and tenascin-R (Tn-R). They enwrap a subset of GABAergic inhibitory interneurons in the cerebral cortex and restrict experience-dependent cortical plasticity. While the expression profile of PNN components has been widely studied in many areas of the central nervous system of various animal species, it remains unclear how these components are expressed during the postnatal development of mouse primary visual cortex (V1). In the present study, we characterized the developmental time course of the formation of PNNs in the mouse primary visual cortex, using the specific antibodies against the two PNN component proteins aggrecan and tenascin-R, or the lectin Wisteria floribunda agglutinin (WFA) that directly binds to glycosaminoglycan chains of chondroitin sulfate proteoglycans (CSPGs). We found that the fluorescence staining signals of both the WFA staining and the antibody against aggrecan rapidly increased in cortical neurons across layers 2-6 during postnatal days (PD) 10-28 and reached a plateau around PD42, suggesting a full construction of PNNs by the end of the critical period. Co-staining with antibodies to Ca(2+) binding protein parvalbumin (PV) demonstrated that the majority of PNN-surrounding cortical neurons are immunoreactive to PV. Similar expression profile of another PNN component tenascin-R was observed in the development of V1. Dark rearing of mice from birth significantly reduced the density of PNN-surrounding neurons. In addition, the expression of two recently identified CSPG receptors - Nogo receptor (NgR) and leukocyte common antigen-related phosphatase (LAR), showed significant increases from PD14 to PD70 in layer 2-6 of cortical PV-positive interneurons in normal reared mice, but decreased significantly in dark-reared ones. Taken together, these results suggest that PNNs form preferentially in cortical PV-positive interneurons in an experience-dependent manner, and reach full maturation around the end of the critical period of V1 development. © Elsevier B.V. All rights reserved.

CHOLINE SUPPLEMENTATION AND DNA METHYLATION IN THE HIPPOCAMPUS AND PREFRONTAL CORTEX OF RATS EXPOSED TO ALCOHOL DURING DEVELOPMENT

PubMed Central

Otero, Nicha K. H.; Thomas, Jennifer D.; Saski, Christopher A.; Xia, Xiaoxia; Kelly, Sandra J.

2012-01-01

Background Some of the most frequent deficits seen in children with FASD and in animal models of FASD are spatial memory impairments and impaired executive functioning, which are likely related to alcohol-induced alterations of the hippocampus and prefrontal cortex (PFC), respectively. Choline, a nutrient supplement, has been shown in a rat model to ameliorate some of alcohol's teratogenic effects and this effect may be mediated through choline' effects on DNA methylation. Methods Alcohol was given by intragastric intubation to rat pups during the neonatal period (postnatal days 2–10) (ET group), which is equivalent to the third trimester in humans and a period of heightened vulnerability of the brain to alcohol exposure. Control groups included an intubated control group given the intubation procedure without alcohol (IC) and a non-treated control group (NC). Choline or saline was administered subcutaneously to each subject from postnatal day 2 to 20. On postnatal day 21, the brains of the subjects were removed and assayed for global DNA methylation patterning as measured by chemiluminescence using the cpGlobal assay in both the hippocampal region and PFC. Results Alcohol exposure caused hypermethylation in the hippocampus and PFC, which was significantly reduced after choline supplementation. In contrast, control animals showed increases in DNA methylation in both regions after choline supplementation, suggesting that choline supplementation has different effects depending upon the initial state of the brain. Conclusions This study is the first to show changes in global DNA methylation of the hippocampal region and PFC after neonatal alcohol exposure. Choline supplementation impacts global DNA methylation in these two brain regions in alcohol-exposed and control animals in a differential manner. The current findings suggest that both alcohol and choline have substantial impact on the epigenome in the prefrontal cortex and hippocampus and future studies will be needed to describe which gene families are impacted in such a way that function of the nervous system is changed. PMID:22509990

Low level postnatal methylmercury exposure in vivo alters developmental forms of short-term synaptic plasticity in the visual cortex of rat

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dasari, Sameera; Yuan, Yukun, E-mail: yuanyuku@msu.ed

2009-11-01

Methylmercury (MeHg) has been previously shown to affect neurotransmitter release. Short-term synaptic plasticity (STP) is primarily related to changes in the probability of neurotransmitter release. To determine if MeHg affects STP development, we examined STP forms in the visual cortex of rat following in vivo MeHg exposure. Neonatal rats received 0 (0.9% NaCl), 0.75 or 1.5 mg/kg/day MeHg subcutaneously for 15 or 30 days beginning on postnatal day 5, after which visual cortical slices were prepared for field potential recordings. In slices prepared from rats treated with vehicle, field excitatory postsynaptic potentials (fEPSPs) evoked by paired-pulse stimulation at 20-200 msmore » inter-stimulus intervals showed a depression (PPD) of the second fEPSP (fEPSP2). PPD was also seen in slices prepared from rats after 15 day treatment with 0.75 or 1.5 mg/kg/day MeHg. However, longer duration treatment (30 days) with either dose of MeHg resulted in paired-pulse facilitation (PPF) of fEPSP2 in the majority of slices examined. PPF remained observable in slices prepared from animals in which MeHg exposure had been terminated for 30 days after completion of the initial 30 day MeHg treatment, whereas slices from control animals still showed PPD. MeHg did not cause any frequency- or region-preferential effect on STP. Manipulations of [Ca{sup 2+}]{sub e} or application of the GABA{sub A} receptor antagonist bicuculline could alter the strength and polarity of MeHg-induced changes in STP. Thus, these data suggest that low level postnatal MeHg exposure interferes with the developmental transformation of STP in the visual cortex, which is a long-lasting effect.« less

[Expression of NR2A in rat auditory cortex after sound insulation and auditory plasticity].

PubMed

Xia, Yin; Long, Haishan; Han, Demin; Gong, Shusheng; Lei, Li; Shi, Jinfeng; Fan, Erzhong; Li, Ying; Zhao, Qing

2009-06-01

To study the changes of N-methyl-D-aspartate (NMDA) receptor subunit 2A (NR2A) expression at local synapses in auditory cortices after early postnatal sound insulation and tone exposure. We prepared highly purified synaptosomes from primary auditory cortex by Optiprep flotation gradient centrifugations, and compared the differences of NR2A expression in sound insulation PND14, PND28, PND42 and Tone exposure after sound insulation for 7 days by Western blotting. The results showed that the NR2A protein expression of PND14 and PND28 decreased significantly (P<0.05). Tone exposure after sound insulation for 7 days, mSIe NR2A protein level increased significantly (P<0.05). It showed bidirectional regulation of NR2A protein. No significant effects of sound insulation and lone exposure were found on the relative expression level of NR2A of PND42 (P>0.05). The results indicate that sound insulation and experience can modify the protein expression level of NR2A during the critical period of rat postnatal development. These findings provide important data for the study on the mechanisms of the developmental plasticity of sensory functions.

Multivariate synaptic and behavioral profiling reveals new developmental endophenotypes in the prefrontal cortex

PubMed Central

Iafrati, Jillian; Malvache, Arnaud; Gonzalez Campo, Cecilia; Orejarena, M. Juliana; Lassalle, Olivier; Bouamrane, Lamine; Chavis, Pascale

2016-01-01

The postnatal maturation of the prefrontal cortex (PFC) represents a period of increased vulnerability to risk factors and emergence of neuropsychiatric disorders. To disambiguate the pathophysiological mechanisms contributing to these disorders, we revisited the endophenotype approach from a developmental viewpoint. The extracellular matrix protein reelin which contributes to cellular and network plasticity, is a risk factor for several psychiatric diseases. We mapped the aggregate effect of the RELN risk allele on postnatal development of PFC functions by cross-sectional synaptic and behavioral analysis of reelin-haploinsufficient mice. Multivariate analysis of bootstrapped datasets revealed subgroups of phenotypic traits specific to each maturational epoch. The preeminence of synaptic AMPA/NMDA receptor content to pre-weaning and juvenile endophenotypes shifts to long-term potentiation and memory renewal during adolescence followed by NMDA-GluN2B synaptic content in adulthood. Strikingly, multivariate analysis shows that pharmacological rehabilitation of reelin haploinsufficient dysfunctions is mediated through induction of new endophenotypes rather than reversion to wild-type traits. By delineating previously unknown developmental endophenotypic sequences, we conceived a promising general strategy to disambiguate the molecular underpinnings of complex psychiatric disorders and for the rational design of pharmacotherapies in these disorders. PMID:27765946

Effects of long-term pre- and post-natal exposure to 2.45 GHz wireless devices on developing male rat kidney.

PubMed

Kuybulu, Ayça Esra; Öktem, Faruk; Çiriş, İbrahim Metin; Sutcu, Recep; Örmeci, Ahmet Rıfat; Çömlekçi, Selçuk; Uz, Efkan

2016-01-01

The aim of the present study was to investigate oxidative stress and apoptosis in kidney tissues of male Wistar rats that pre- and postnatally exposed to wireless electromagnetic field (EMF) with an internet frequency of 2.45 GHz for a long time. The study was conducted in three groups of rats which were pre-natal, post-natal. and sham exposed groups. Oxidative stress markers and histological evaluation of kidney tissues were studied. Renal tissue malondialdehyde (MDA) and total oxidant (TOS) levels of pre-natal group were high and total antioxidant (TAS) and superoxide dismutase (SOD) levels were low. Spot urine NAG/creatinine ratio was significantly higher in pre- and post-natal groups (p < 0.001). Tubular injury was detected in most of the specimens in post-natal groups. Immunohistochemical analysis showed low-intensity staining with Bax in cortex, high-intensity staining with Bcl-2 in cortical and medullar areas of pre-natal group (p values, 0.000, 0.002, 0.000, respectively) when compared with sham group. Bcl2/Bax staining intensity ratios of medullar and cortical area was higher in pre-natal group than sham group (p = 0.018, p = 0.011). Based on this study, it is thought that chronic pre- and post-natal period exposure to wireless internet frequency of EMF may cause chronic kidney damages; staying away from EMF source in especially pregnancy and early childhood period may reduce negative effects of exposure on kidney.

Neuronal Migration Dynamics in the Developing Ferret Cortex.

PubMed

Gertz, Caitlyn C; Kriegstein, Arnold R

2015-10-21

During mammalian neocortical development, newborn excitatory and inhibitory neurons must migrate over long distances to reach their final positions within the cortical plate. In the lissencephalic rodent brain, pyramidal neurons are born in the ventricular and subventricular zones of the pallium and migrate along radial glia fibers to reach the appropriate cortical layer. Although much less is known about neuronal migration in species with a gyrencephalic cortex, retroviral studies in the ferret and primate suggest that, unlike the rodent, pyramidal neurons do not follow strict radial pathways and instead can disperse horizontally. However, the means by which pyramidal neurons laterally disperse remain unknown. In this study, we identified a viral labeling technique for visualizing neuronal migration in the ferret, a gyrencephalic carnivore, and found that migration was predominantly radial at early postnatal ages. In contrast, neurons displayed more tortuous migration routes with a decreased frequency of cortical plate-directed migration at later stages of neurogenesis concomitant with the start of brain folding. This was accompanied by neurons migrating sequentially along several different radial glial fibers, suggesting a mode by which pyramidal neurons may laterally disperse in a folded cortex. These findings provide insight into the migratory behavior of neurons in gyrencephalic species and provide a framework for using nonrodent model systems for studying neuronal migration disorders. Elucidating neuronal migration dynamics in the gyrencephalic, or folded, cortex is important for understanding neurodevelopmental disorders. Similar to the rodent, we found that neuronal migration was predominantly radial at early postnatal ages in the gyrencephalic ferret cortex. Interestingly, ferret neurons displayed more tortuous migration routes and a decreased frequency of radial migration at later ages coincident with the start of cortical folding. We found that ferret neurons use several different radial glial fibers as migratory guides, including those belonging to the recently described outer radial glia, suggesting a mechanism by which ferret neurons disperse laterally. It is likely that excitatory neurons horizontally disperse in other gyrencephalic mammals, including the primate, suggesting an important modification to the current model deduced primarily from the rodent. Copyright © 2015 the authors 0270-6474/15/3514307-09$15.00/0.

Postnatal development of A-type and Kv1- and Kv2-mediated potassium channel currents in neocortical pyramidal neurons

PubMed Central

Guan, Dongxu; Horton, Leslie R.; Armstrong, William E.

2011-01-01

Potassium channels regulate numerous aspects of neuronal excitability, and several voltage-gated K+ channel subunits have been identified in pyramidal neurons of rat neocortex. Previous studies have either considered the development of outward current as a whole or divided currents into transient, A-type and persistent, delayed rectifier components but did not differentiate between current components defined by α-subunit type. To facilitate comparisons of studies reporting K+ currents from animals of different ages and to understand the functional roles of specific current components, we characterized the postnatal development of identified Kv channel-mediated currents in pyramidal neurons from layers II/III from rat somatosensory cortex. Both the persistent/slowly inactivating and transient components of the total K+ current increased in density with postnatal age. We used specific pharmacological agents to test the relative contributions of putative Kv1- and Kv2-mediated currents (100 nM α-dendrotoxin and 600 nM stromatoxin, respectively). A combination of voltage protocol, pharmacology, and curve fitting was used to isolate the rapidly inactivating A-type current. We found that the density of all identified current components increased with postnatal age, approaching a plateau at 3–5 wk. We found no significant changes in the relative proportions or kinetics of any component between postnatal weeks 1 and 5, except that the activation time constant for A-type current was longer at 1 wk. The putative Kv2-mediated component was the largest at all ages. Immunocytochemistry indicated that protein expression for Kv4.2, Kv4.3, Kv1.4, and Kv2.1 increased between 1 wk and 4–5 wk of age. PMID:21451062

Postnatal development of A-type and Kv1- and Kv2-mediated potassium channel currents in neocortical pyramidal neurons.

PubMed

Guan, Dongxu; Horton, Leslie R; Armstrong, William E; Foehring, Robert C

2011-06-01

Potassium channels regulate numerous aspects of neuronal excitability, and several voltage-gated K(+) channel subunits have been identified in pyramidal neurons of rat neocortex. Previous studies have either considered the development of outward current as a whole or divided currents into transient, A-type and persistent, delayed rectifier components but did not differentiate between current components defined by α-subunit type. To facilitate comparisons of studies reporting K(+) currents from animals of different ages and to understand the functional roles of specific current components, we characterized the postnatal development of identified Kv channel-mediated currents in pyramidal neurons from layers II/III from rat somatosensory cortex. Both the persistent/slowly inactivating and transient components of the total K(+) current increased in density with postnatal age. We used specific pharmacological agents to test the relative contributions of putative Kv1- and Kv2-mediated currents (100 nM α-dendrotoxin and 600 nM stromatoxin, respectively). A combination of voltage protocol, pharmacology, and curve fitting was used to isolate the rapidly inactivating A-type current. We found that the density of all identified current components increased with postnatal age, approaching a plateau at 3-5 wk. We found no significant changes in the relative proportions or kinetics of any component between postnatal weeks 1 and 5, except that the activation time constant for A-type current was longer at 1 wk. The putative Kv2-mediated component was the largest at all ages. Immunocytochemistry indicated that protein expression for Kv4.2, Kv4.3, Kv1.4, and Kv2.1 increased between 1 wk and 4-5 wk of age.

Neuroblast Distribution after Cortical Impact Is Influenced by White Matter Injury in the Immature Gyrencephalic Brain

PubMed Central

Taylor, Sabrina R.; Smith, Colin M.; Keeley, Kristen L.; McGuone, Declan; Dodge, Carter P.; Duhaime, Ann-Christine; Costine, Beth A.

2016-01-01

Cortical contusions are a common type of traumatic brain injury (TBI) in children. Current knowledge of neuroblast response to cortical injury arises primarily from studies utilizing aspiration or cryoinjury in rodents. In infants and children, cortical impact affects both gray and white matter and any neurogenic response may be complicated by the large expanse of white matter between the subventricular zone (SVZ) and the cortex, and the large number of neuroblasts in transit along the major white matter tracts to populate brain regions. Previously, we described an age-dependent increase of neuroblasts in the SVZ in response to cortical impact in the immature gyrencephalic brain. Here, we investigate if neuroblasts target the injury, if white matter injury influences repair efforts, and if postnatal population of brain regions are disrupted. Piglets received a cortical impact to the rostral gyrus cortex or sham surgery at postnatal day (PND) 7, BrdU 2 days prior to (PND 5 and 6) or after injury (PND 7 and 8), and brains were collected at PND 14. Injury did not alter the number of neuroblasts in the white matter between the SVZ and the rostral gyrus. In the gray matter of the injury site, neuroblast density was increased in cavitated lesions, and the number of BrdU+ neuroblasts was increased, but comprised less than 1% of all neuroblasts. In the white matter of the injury site, neuroblasts with differentiating morphology were densely arranged along the cavity edge. In a ventral migratory stream, neuroblast density was greater in subjects with a cavitated lesion, indicating that TBI may alter postnatal development of regions supplied by that stream. Cortical impact in the immature gyrencephalic brain produced complicated and variable lesions, increased neuroblast density in cavitated gray matter, resulted in potentially differentiating neuroblasts in the white matter, and may alter the postnatal population of brain regions utilizing a population of neuroblasts that were born prior to PND 5. This platform may be useful to continue to study potential complications of white matter injury and alterations of postnatal population of brain regions, which may contribute to the chronic effects of TBI in children. PMID:27601978

Unravelling the development of the visual cortex: implications for plasticity and repair

PubMed Central

Bourne, James A

2010-01-01

The visual cortex comprises over 50 areas in the human, each with a specified role and distinct physiology, connectivity and cellular morphology. How these individual areas emerge during development still remains something of a mystery and, although much attention has been paid to the initial stages of the development of the visual cortex, especially its lamination, very little is known about the mechanisms responsible for the arealization and functional organization of this region of the brain. In recent years we have started to discover that it is the interplay of intrinsic (molecular) and extrinsic (afferent connections) cues that are responsible for the maturation of individual areas, and that there is a spatiotemporal sequence in the maturation of the primary visual cortex (striate cortex, V1) and the multiple extrastriate/association areas. Studies in both humans and non-human primates have started to highlight the specific neural underpinnings responsible for the maturation of the visual cortex, and how experience-dependent plasticity and perturbations to the visual system can impact upon its normal development. Furthermore, damage to specific nuclei of the visual cortex, such as the primary visual cortex (V1), is a common occurrence as a result of a stroke, neurotrauma, disease or hypoxia in both neonates and adults alike. However, the consequences of a focal injury differ between the immature and adult brain, with the immature brain demonstrating a higher level of functional resilience. With better techniques for examining specific molecular and connectional changes, we are now starting to uncover the mechanisms responsible for the increased neural plasticity that leads to significant recovery following injury during this early phase of life. Further advances in our understanding of postnatal development/maturation and plasticity observed during early life could offer new strategies to improve outcomes by recapitulating aspects of the developmental program in the adult brain. PMID:20722872

Impaired GABAergic inhibition in the prefrontal cortex of early postnatal phencyclidine (PCP)-treated rats.

PubMed

Kjaerby, Celia; Broberg, Brian V; Kristiansen, Uffe; Dalby, Nils Ole

2014-09-01

A compromised γ-aminobutyric acid (GABA)ergic system is hypothesized to be part of the underlying pathophysiology of schizophrenia. N-methyl-D-aspartate (NMDA) receptor hypofunction during neurodevelopment is proposed to disrupt maturation of interneurons causing an impaired GABAergic transmission in adulthood. The present study examines prefrontal GABAergic transmission in adult rats administered with the NMDA receptor channel blocker, phencyclidine (PCP), for 3 days during the second postnatal week. Whole-cell patch-clamp recordings from pyramidal cells in PCP-treated rats showed a 22% reduction in the frequency of miniature inhibitory postsynaptic currents in layer II/III, but not in layer V pyramidal neurons of the prefrontal cortex. Furthermore, early postnatal PCP treatment caused insensitivity toward effects of the GABA transporter 1 (GAT-1) inhibitor, 1,2,5,6-tetrahydro-1-[2-[[(diphenyl-methylene)amino]oxy]ethyl]-3-pyridinecarboxylic acid, and also diminished currents passed by δ-subunit-containing GABAA receptors in layer II/III pyramidal neurons. The observed impairments in GABAergic function are compatible with the alteration of GABAergic markers as well as cognitive dysfunction observed in early postnatal PCP-treated rats and support the hypothesis that PCP administration during neurodevelopment affects the functionality of interneurons in later life. © The Author 2013. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Expression of the IGF and the aromatase/estrogen receptor systems in human adrenal tissues from early infancy to late puberty: implications for the development of adrenarche.

PubMed

Belgorosky, Alicia; Baquedano, María Sonia; Guercio, Gabriela; Rivarola, Marco A

2009-03-01

Adrenarche is a process of postnatal sexual maturation occurring in higher primates, in which there is an increase in the secretion of adrenal androgens. It is the consequence of a process of postnatal organogenesis characterized by the development of a new zone in the adrenal cortex, the zona reticularis (ZR). The mechanism of this phenomenon remains poorly understood, suggesting that it might be a multifactorial event. A relationship between circulating IGF-I, insulin sensitivity, and adrenal androgens has been postulated. Boys and girls have different patterns of changes in insulin sensitivity at puberty, perhaps secondary to differences in the estrogen milieu. Estrogen effects may also play a role in premature adrenarche. Peripheral or local IGF-1 actions could regulate adrenal progenitor cell proliferation and migration. Since adrenal progenitor cells as well as IGF-I and the IGF-R1 are located in the outer zone of the adrenal cortex during childhood and adolescence, this peripheral cell layer, below the capsule, may contain undifferentiated progenitor cells. Therefore, the IGF-R1 signaling pathway might positively modulate the proliferation and migration of adrenal progenitor cell to stimulate the development of adrenal zones, including ZR. However, no evidence of a direct action of IGF-I on ZR was found. In addition, a role for estrogens in the ontogenesis of ZR is suggested by the presence of aromatase (CYP19) in the subcapsular zona glomerulosa and in the adrenal medulla. Estrogens produced locally could act on ZR by interacting with estrogen receptor beta (ERbeta), but not alpha, and membrane estrogen receptor GPR-30. An estradiol-induced increase in DHEA/cortisol ratio was indeed seen in cultures of adrenocortical cells from post-adrenarche adrenals. In summary, several lines of evidence point to the action of multiple factors, such as local adrenal maturational changes and peripheral metabolic signals, on postnatal human adrenal gland ZR formation.

Genetic Otx2 mis-localization delays critical period plasticity across brain regions.

PubMed

Lee, H H C; Bernard, C; Ye, Z; Acampora, D; Simeone, A; Prochiantz, A; Di Nardo, A A; Hensch, T K

2017-05-01

Accumulation of non-cell autonomous Otx2 homeoprotein in postnatal mouse visual cortex (V1) has been implicated in both the onset and closure of critical period (CP) plasticity. Here, we show that a genetic point mutation in the glycosaminoglycan recognition motif of Otx2 broadly delays the maturation of pivotal parvalbumin-positive (PV+) interneurons not only in V1 but also in the primary auditory (A1) and medial prefrontal cortex (mPFC). Consequently, not only visual, but also auditory plasticity is delayed, including the experience-dependent expansion of tonotopic maps in A1 and the acquisition of acoustic preferences in mPFC, which mitigates anxious behavior. In addition, Otx2 mis-localization leads to dynamic turnover of selected perineuronal net (PNN) components well beyond the normal CP in V1 and mPFC. These findings reveal widespread actions of Otx2 signaling in the postnatal cortex controlling the maturational trajectory across modalities. Disrupted PV+ network function and deficits in PNN integrity are implicated in a variety of psychiatric illnesses, suggesting a potential global role for Otx2 function in establishing mental health.

Postnatal development of EEG patterns, catecholamine contents and myelination, and effect of hyperthyroidism in Suncus brain.

PubMed

Takeuchi, T; Sitizyo, K; Harada, E

1998-03-01

The postnatal development of the central nervous system (CNS) in house musk shrew in the early stage of maturation was studied. The electroencephalogram (EEG) and visual evoked potential (VEP) in association with catecholamine contents and myelin basic protein (MBP) immunoreactivity were carried out from the 1st to the 20th day of postnatal age. Different EEG patterns which were specific to behavioral states (awake and drowsy) were first recorded on the 5th day, and the total power which was obtained by power spectrum analysis increased after this stage. The latencies of all peaks in VEP markedly shortened between the 5th and the 7th day. Noradrenalin (NA) content of the brain showed a slight increase after the 3rd day, and reached maximum levels on the 7th day, which was delayed a few days compared to dopamine (DA). In hyperthyroidism, the peak latency of VEP was shortened and biosynthesis of NA in cerebral cortex and DA in hippocampus was accelerated. The most obvious change in MBP-immunoreactivity of the telencephalon occurred from the 7th to the 10th day. These morphological changes in the brain advanced at the identical time-course to those in the electrophysiological development and increment of DA and NA contents.

Postnatal functional inactivation of the entorhinal cortex or ventral subiculum has different consequences for latent inhibition-related striatal dopaminergic responses in adult rats.

PubMed

Meyer, F; Peterschmitt, Y; Louilot, A

2009-05-01

Latent inhibition has been found to be disrupted in patients with acute schizophrenia. Striatal dopaminergic dysregulation is commonly acknowledged in schizophrenia. This disease may be consecutive to a functional disconnection between integrative regions, stemming from neurodevelopmental failures. Various anomalies suggesting early abnormal brain development have been described in the entorhinal cortex (ENT) and ventral subiculum (SUB) of patients. This study examines the consequences of a neonatal transitory blockade of the left ENT or left SUB for latent inhibition-related dopamine responses in the anterior part of the dorsal striatum using in-vivo voltammetry in freely moving adult rats. Reversible inactivation of both structures in different animals was achieved by local microinjection of tetrodotoxin (TTX) at postnatal day 8. Results obtained during the retention session of a three-stage latent inhibition protocol showed that the functional neonatal disconnection of the ENT or SUB caused the behavioural latent inhibition expression in pre-exposed (PE)-TTX-conditioned adult rats to disappear. After postnatal inactivation of the SUB, PE-TTX-conditioned rats displayed a reversal of the latent inhibition-related striatal dopamine responses, whereas after neonatal blockade of the ENT, dopamine changes in PE-TTX-conditioned rats monitored in the anterior striatum were between those observed in PE-phosphate-buffered-saline-conditioned and non-PE-TTX-conditioned animals. These data suggest that neonatal functional inactivation of the SUB disrupts latent inhibition-related striatal dopamine responses in adult animals more than that of the ENT. They may help improve understanding of the pathophysiology of schizophrenia.

Long-Lasting Crossmodal Cortical Reorganization Triggered by Brief Postnatal Visual Deprivation.

PubMed

Collignon, Olivier; Dormal, Giulia; de Heering, Adelaide; Lepore, Franco; Lewis, Terri L; Maurer, Daphne

2015-09-21

Animal and human studies have demonstrated that transient visual deprivation early in life, even for a very short period, permanently alters the response properties of neurons in the visual cortex and leads to corresponding behavioral visual deficits. While it is acknowledged that early-onset and longstanding blindness leads the occipital cortex to respond to non-visual stimulation, it remains unknown whether a short and transient period of postnatal visual deprivation is sufficient to trigger crossmodal reorganization that persists after years of visual experience. In the present study, we characterized brain responses to auditory stimuli in 11 adults who had been deprived of all patterned vision at birth by congenital cataracts in both eyes until they were treated at 9 to 238 days of age. When compared to controls with typical visual experience, the cataract-reversal group showed enhanced auditory-driven activity in focal visual regions. A combination of dynamic causal modeling with Bayesian model selection indicated that this auditory-driven activity in the occipital cortex was better explained by direct cortico-cortical connections with the primary auditory cortex than by subcortical connections. Thus, a short and transient period of visual deprivation early in life leads to enduring large-scale crossmodal reorganization of the brain circuitry typically dedicated to vision. Copyright © 2015 Elsevier Ltd. All rights reserved.

Distinct Translaminar Glutamatergic Circuits to GABAergic Interneurons in the Neonatal Auditory Cortex.

PubMed

Deng, Rongkang; Kao, Joseph P Y; Kanold, Patrick O

2017-05-09

GABAergic activity is important in neocortical development and plasticity. Because the maturation of GABAergic interneurons is regulated by neural activity, the source of excitatory inputs to GABAergic interneurons plays a key role in development. We show, by laser-scanning photostimulation, that layer 4 and layer 5 GABAergic interneurons in the auditory cortex in neonatal mice (

Development of neuropeptide Y (NPY) immunoreactive neurons in the rat occipital cortex: A combined immunohistochemical-autoradiographic study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cavanagh, M.E.; Parnavelas, J.G.

1990-07-22

The postnatal development of neuropeptide Y (NPY)-immunoreactive neurons, previously labeled with (3H)thymidine on embryonic days E14-E21, has been studied in the rat occipital cortex. Immunohistochemistry combined with autoradiography showed evidence of a modified inside-out pattern of maturation. NPY-neurons are generated between E14 and E20 and are found in layers II-VI of the cortex and the subcortical white matter. NPY neurons from all these birthdates are overproduced at first, although cells generated at E16 produce the greatest excess, followed by E15 and E17. Some of these transient neurons are found in the wrong layer for their birthdates, and their elimination producesmore » a more correct alignment at maturity. However, most of the NPY neurons that survive are generated at E17, and these cells are found throughout layers II-VI with a preponderance in layer VI. This evidence is strongly suggestive of cell death rather than merely cessation of production of NPY.« less

Restoring auditory cortex plasticity in adult mice by restricting thalamic adenosine signaling

DOE PAGES

Blundon, Jay A.; Roy, Noah C.; Teubner, Brett J. W.; ...

2017-06-30

Circuits in the auditory cortex are highly susceptible to acoustic influences during an early postnatal critical period. The auditory cortex selectively expands neural representations of enriched acoustic stimuli, a process important for human language acquisition. Adults lack this plasticity. We show in the murine auditory cortex that juvenile plasticity can be reestablished in adulthood if acoustic stimuli are paired with disruption of ecto-5'-nucleotidase–dependent adenosine production or A1–adenosine receptor signaling in the auditory thalamus. This plasticity occurs at the level of cortical maps and individual neurons in the auditory cortex of awake adult mice and is associated with long-term improvement ofmore » tone-discrimination abilities. We determined that, in adult mice, disrupting adenosine signaling in the thalamus rejuvenates plasticity in the auditory cortex and improves auditory perception.« less

Restoring auditory cortex plasticity in adult mice by restricting thalamic adenosine signaling

DOE Office of Scientific and Technical Information (OSTI.GOV)

Blundon, Jay A.; Roy, Noah C.; Teubner, Brett J. W.

Circuits in the auditory cortex are highly susceptible to acoustic influences during an early postnatal critical period. The auditory cortex selectively expands neural representations of enriched acoustic stimuli, a process important for human language acquisition. Adults lack this plasticity. We show in the murine auditory cortex that juvenile plasticity can be reestablished in adulthood if acoustic stimuli are paired with disruption of ecto-5'-nucleotidase–dependent adenosine production or A1–adenosine receptor signaling in the auditory thalamus. This plasticity occurs at the level of cortical maps and individual neurons in the auditory cortex of awake adult mice and is associated with long-term improvement ofmore » tone-discrimination abilities. We determined that, in adult mice, disrupting adenosine signaling in the thalamus rejuvenates plasticity in the auditory cortex and improves auditory perception.« less

Early Postnatal Lesion of the Medial Dorsal Nucleus Leads to Loss of Dendrites and Spines in Adult Prefrontal Cortex

PubMed Central

Marmolejo, Naydu; Paez, Jesse; Levitt, Jonathan B.; Jones, Liesl B.

2013-01-01

Research suggests that the medial dorsal nucleus (MD) of the thalamus influences pyramidal cell development in the prefrontal cortex (PFC) in an activity-dependent manner. The MD is reciprocally connected to the PFC. Many psychiatric disorders, such as schizophrenia, affect the PFC, and one of the most consistent findings in schizophrenia is a decrease in volume and neuronal number in the MD. Therefore, understanding the role the MD plays in the development of the PFC is important and may help in understanding the progression of psychiatric disorders that have their root in development. Focusing on the interplay between the MD and the PFC, this study examined the hypothesis that the MD plays a role in the dendritic development of pyramidal cells in the PFC. Unilateral electrolytic lesions of the MD in Long-Evans rat pups were made on postnatal day 4 (P4), and the animals developed to P60. We then examined dendritic morphology by examining MAP2 immunostaining and by using Golgi techniques to determine basilar dendrite number and spine density. Additionally, we examined pyramidal cell density in cingulate area 1 (Cg1), prelimbic region, and dorsolateral anterior cortex, which receive afferents from the MD. Thalamic lesions caused a mean MD volume decrease of 12.4% which led to a significant decrease in MAP2 staining in both superficial and deep layers in all 3 cortical areas. The lesions also caused a significant decrease in spine density and in the number of primary and secondary basilar dendrites on superficial and deep layer pyramidal neurons in all 3 regions. No significant difference was observed in pyramidal cell density in any of the regions or layers, but a nonsignificant increase in cell density was observed in 2 regions. Our data are thus consistent with the hypothesis that the MD plays a role in the development of the PFC and, therefore, may be a good model to begin to examine neurodevelopmental disorders such as autism and schizophrenia. PMID:23406908

Methylphenidate treatment increases Na(+), K (+)-ATPase activity in the cerebrum of young and adult rats.

PubMed

Scherer, Emilene B S; Matté, Cristiane; Ferreira, Andréa G K; Gomes, Karin M; Comim, Clarissa M; Mattos, Cristiane; Quevedo, João; Streck, Emilio L; Wyse, Angela T S

2009-12-01

Methylphenidate is a central nervous system stimulant used for the treatment of attention-deficit hyperactivity disorder. Na(+), K(+)-ATPase is a membrane-bound enzyme necessary to maintain neuronal excitability. Considering that methylphenidate effects on central nervous system metabolism are poorly known and that Na(+), K(+)-ATPase is essential to normal brain function, the purpose of this study was to evaluate the effect of this drug on Na(+), K(+)-ATPase activity in the cerebrum of young and adult rats. For acute administration, a single injection of methylphenidate (1.0, 2.0, or 10.0 mg/Kg) or saline was given to rats on postnatal day 25 or postnatal day 60, in the young and adult groups, respectively. For chronic administration, methylphenidate (1.0, 2.0, or 10.0 mg/Kg) or saline injections were given to young rats starting at postnatal day 25 once daily for 28 days. In adult rats, the same regimen was performed starting at postnatal day 60. Our results showed that acute methylphenidate administration increased Na(+), K(+)-ATPase activity in hippocampus, prefrontal cortex, and striatum of young and adult rats. In young rats, chronic administration of methylphenidate also enhanced Na(+), K(+)-ATPase activity in hippocampus and prefrontal cortex, but not in striatum. When tested in adult rats, Na(+), K(+)-ATPase activity was increased in all cerebral structures studied. The present findings suggest that increased Na(+), K(+)-ATPase activity may be associated with neuronal excitability caused by methylphenidate.

NFIX Regulates Neural Progenitor Cell Differentiation During Hippocampal Morphogenesis

PubMed Central

Heng, Yee Hsieh Evelyn; McLeay, Robert C.; Harvey, Tracey J.; Smith, Aaron G.; Barry, Guy; Cato, Kathleen; Plachez, Céline; Little, Erica; Mason, Sharon; Dixon, Chantelle; Gronostajski, Richard M.; Bailey, Timothy L.; Richards, Linda J.; Piper, Michael

2014-01-01

Neural progenitor cells have the ability to give rise to neurons and glia in the embryonic, postnatal and adult brain. During development, the program regulating whether these cells divide and self-renew or exit the cell cycle and differentiate is tightly controlled, and imbalances to the normal trajectory of this process can lead to severe functional consequences. However, our understanding of the molecular regulation of these fundamental events remains limited. Moreover, processes underpinning development of the postnatal neurogenic niches within the cortex remain poorly defined. Here, we demonstrate that Nuclear factor one X (NFIX) is expressed by neural progenitor cells within the embryonic hippocampus, and that progenitor cell differentiation is delayed within Nfix−/− mice. Moreover, we reveal that the morphology of the dentate gyrus in postnatal Nfix−/− mice is abnormal, with fewer subgranular zone neural progenitor cells being generated in the absence of this transcription factor. Mechanistically, we demonstrate that the progenitor cell maintenance factor Sry-related HMG box 9 (SOX9) is upregulated in the hippocampus of Nfix−/− mice and demonstrate that NFIX can repress Sox9 promoter-driven transcription. Collectively, our findings demonstrate that NFIX plays a central role in hippocampal morphogenesis, regulating the formation of neuronal and glial populations within this structure. PMID:23042739

FOXG1 Is Responsible for the Congenital Variant of Rett Syndrome

PubMed Central

Ariani, Francesca; Hayek, Giuseppe; Rondinella, Dalila; Artuso, Rosangela; Mencarelli, Maria Antonietta; Spanhol-Rosseto, Ariele; Pollazzon, Marzia; Buoni, Sabrina; Spiga, Ottavia; Ricciardi, Sara; Meloni, Ilaria; Longo, Ilaria; Mari, Francesca; Broccoli, Vania; Zappella, Michele; Renieri, Alessandra

2008-01-01

Rett syndrome is a severe neurodevelopmental disease caused by mutations in the X-linked gene encoding for the methyl-CpG-binding protein MeCP2. Here, we report the identification of FOXG1-truncating mutations in two patients affected by the congenital variant of Rett syndrome. FOXG1 encodes a brain-specific transcriptional repressor that is essential for early development of the telencephalon. Molecular analysis revealed that Foxg1 might also share common molecular mechanisms with MeCP2 during neuronal development, exhibiting partially overlapping expression domain in postnatal cortex and neuronal subnuclear localization. PMID:18571142

Brain metabolic alterations in mice subjected to postnatal traumatic stress and in their offspring.

PubMed

Gapp, Katharina; Corcoba, Alberto; van Steenwyk, Gretchen; Mansuy, Isabelle M; Duarte, João Mn

2017-07-01

Adverse environmental and social conditions early in life have a strong impact on health. They are major risk factors for mental diseases in adulthood and, in some cases, their effects can be transmitted across generations. The consequences of detrimental stress conditions on brain metabolism across generations are not well known. Using high-field (14.1 T) magnetic resonance spectroscopy, we investigated the neurochemical profile of adult male mice exposed to traumatic stress in early postnatal life and of their offspring, and of undisturbed control mice. We found that, relative to controls, early life stress-exposed mice have metabolic alterations consistent with neuronal dysfunction, including reduced concentration of N-acetylaspartate, glutamate and γ-aminobutyrate, in the prefrontal cortex in basal conditions. Their offspring have normal neurochemical profiles in basal conditions. Remarkably, when challenged by an acute cold swim stress, the offspring has attenuated metabolic responses in the prefrontal cortex, hippocampus and striatum. In particular, the expected stress-induced reduction in the concentration of N-acetylaspartate, a putative marker of neuronal health, was prevented in the cortex and hippocampus. These findings suggest that paternal trauma can confer beneficial brain metabolism adaptations to acute stress in the offspring.

Early postnatal development of vasoactive intestinal polypeptide- and peptide histidine isoleucine-immunoreactive structures in the cat visual cortex.

PubMed

Wahle, P; Meyer, G

1989-04-08

The early postnatal development of neurons containing vasoactive intestinal polypeptide (VIP) and peptide histidine isoleucine (PHI) has been analyzed in visual areas 17 and 18 of cats aged from postnatal day (P) 0 to adulthood. Neuronal types are established mainly by axonal criteria. Both peptides occur in the same neuronal types and display the same postnatal chronology of appearance. Several cell types are transient, which means that they are present in the cortex only for a limited period of development. According to their chronology of appearance the VIP/PHI-immunoreactive (ir) cell types are grouped into three neuronal populations. The first population comprises six cell types which appear early in postnatal life. The pseudohorsetail cells of layer I possess a vertically descending axon which initially gives rise to recurrent collaterals, then forms a bundle passing layers III to V, and finally, horizontal terminal fibers in layer VI. The neurons differentiate at P 4 and disappear by degeneration around P 30. The neurons with columnar dendritic fields of layers IV/V are characterized by a vertical arrangement of long dendrites ascending or descending parallel to each other, thus forming an up to 600 microns long dendritic column. Their axons always descend and terminate in broad fields in layer VI. The neurons appear at P 7 and are present until P 20. The multipolar neurons of layer VI occur in isolated positions and have broad axonal territories. The neurons differentiate at P 7 and persist into adulthood. Bitufted to multipolar neurons of layers II/III have axons descending as a single fiber to layer VI, where they terminate. The neurons appear at P 12 and persist into adulthood. The four cell types described above issue a vertically oriented fiber architecture in layers II-V and a horizontal terminal plexus in layer VI which is dense during the second, third and fourth week. Concurrent with the disappearance of the two transient types the number of descending axonal bundles and the density of the layer VI plexus is reduced, but the latter is maintained during adulthood by the two persisting cell types. Two further cell types belong to the first population: The transient bipolar cells of layers IV, V, and VI have long dendrites which extend through the entire cortical width. Their axons always descend, leave the gray matter, and apparently terminate in the upper white matter. The neurons differentiate concurrently with the pseudohorsetail cells at P 4, are very frequent during the following weeks, and eventually disappear at P 30.(ABSTRACT TRUNCATED AT 400 WORDS)

Fgf receptor 3 activation promotes selective growth and expansion of occipitotemporal cortex

PubMed Central

Thomson, Rachel E; Kind, Peter C; Graham, Nicholas A; Etherson, Michelle L; Kennedy, John; Fernandes, Ana C; Marques, Catia S; Hevner, Robert F; Iwata, Tomoko

2009-01-01

Background Fibroblast growth factors (Fgfs) are important regulators of cerebral cortex development. Fgf2, Fgf8 and Fgf17 promote growth and specification of rostromedial (frontoparietal) cortical areas. Recently, the function of Fgf15 in antagonizing Fgf8 in the rostral signaling center was also reported. However, regulation of caudal area formation by Fgf signaling remains unknown. Results In mutant mice with constitutive activation of Fgf receptor 3 (Fgfr3) in the forebrain, surface area of the caudolateral cortex was markedly expanded at early postnatal stage, while rostromedial surface area remained normal. Cortical thickness was also increased in caudal regions. The expression domain and levels of Fgf8, as well as overall patterning, were unchanged. In contrast, the changes in caudolateral surface area were associated with accelerated cell cycle in early stages of neurogenesis without an alteration of cell cycle exit. Moreover, a marked overproduction of intermediate neuronal progenitors was observed in later stages, indicating prolongation of neurogenesis. Conclusion Activation of Fgfr3 selectively promotes growth of caudolateral (occipitotemporal) cortex. These observations support the 'radial unit' and 'radial amplification' hypotheses and may explain premature sulcation of the occipitotemporal cortex in thanatophoric dysplasia, a human FGFR3 disorder. Together with previous work, this study suggests that formation of rostral and caudal areas are differentially regulated by Fgf signaling in the cerebral cortex. PMID:19192266

Large-scale oscillatory calcium waves in the immature cortex.

PubMed

Garaschuk, O; Linn, J; Eilers, J; Konnerth, A

2000-05-01

Two-photon imaging of large neuronal networks in cortical slices of newborn rats revealed synchronized oscillations in intracellular Ca2+ concentration. These spontaneous Ca2+ waves usually started in the posterior cortex and propagated slowly (2.1 mm per second) toward its anterior end. Ca2+ waves were associated with field-potential changes and required activation of AMPA and NMDA receptors. Although GABAA receptors were not involved in wave initiation, the developmental transition of GABAergic transmission from depolarizing to hyperpolarizing (around postnatal day 7) stopped the oscillatory activity. Thus we identified a type of large-scale Ca2+ wave that may regulate long-distance wiring in the immature cortex.

Relationship between individual neuron and network spontaneous activity in developing mouse cortex.

PubMed

Barnett, Heather M; Gjorgjieva, Julijana; Weir, Keiko; Comfort, Cara; Fairhall, Adrienne L; Moody, William J

2014-12-15

Spontaneous synchronous activity (SSA) that propagates as electrical waves is found in numerous central nervous system structures and is critical for normal development, but the mechanisms of generation of such activity are not clear. In previous work, we showed that the ventrolateral piriform cortex is uniquely able to initiate SSA in contrast to the dorsal neocortex, which participates in, but does not initiate, SSA (Lischalk JW, Easton CR, Moody WJ. Dev Neurobiol 69: 407-414, 2009). In this study, we used Ca(2+) imaging of cultured embryonic day 18 to postnatal day 2 coronal slices (embryonic day 17 + 1-4 days in culture) of the mouse cortex to investigate the different activity patterns of individual neurons in these regions. In the piriform cortex where SSA is initiated, a higher proportion of neurons was active asynchronously between waves, and a larger number of groups of coactive cells was present compared with the dorsal cortex. When we applied GABA and glutamate synaptic antagonists, asynchronous activity and cellular clusters remained, while synchronous activity was eliminated, indicating that asynchronous activity is a result of cell-intrinsic properties that differ between these regions. To test the hypothesis that higher levels of cell-autonomous activity in the piriform cortex underlie its ability to initiate waves, we constructed a conductance-based network model in which three layers differed only in the proportion of neurons able to intrinsically generate bursting behavior. Simulations using this model demonstrated that a gradient of intrinsic excitability was sufficient to produce directionally propagating waves that replicated key experimental features, indicating that the higher level of cell-intrinsic activity in the piriform cortex may provide a substrate for SSA generation. Copyright © 2014 the American Physiological Society.

Prenatal cocaine exposure decreases parvalbumin-immunoreactive neurons and GABA-to-projection neuron ratio in the medial prefrontal cortex.

PubMed

McCarthy, Deirdre M; Bhide, Pradeep G

2012-01-01

Cocaine abuse during pregnancy produces harmful effects not only on the mother but also on the unborn child. The neurotransmitters dopamine and serotonin are known as the principal targets of the action of cocaine in the fetal and postnatal brain. However, recent evidence suggests that cocaine can impair cerebral cortical GABA neuron development and function. We sought to analyze the effects of prenatal cocaine exposure on the number and distribution of GABA and projection neurons (inhibitory interneurons and excitatory output neurons, respectively) in the mouse cerebral cortex. We found that the prenatal cocaine exposure decreased GABA neuron numbers and GABA-to-projection neuron ratio in the medial prefrontal cortex of 60-day-old mice. The neighboring prefrontal cortex did not show significant changes in either of these measures. However, there was a significant increase in projection neuron numbers in the prefrontal cortex but not in the medial prefrontal cortex. Thus, the effects of cocaine on GABA and projection neurons appear to be cortical region specific. The population of parvalbumin-immunoreactive GABA neurons was decreased in the medial prefrontal cortex following the prenatal cocaine exposure. The cocaine exposure also delayed the developmental decline in the volume of the medial prefrontal cortex. Thus, prenatal cocaine exposure produced persisting and region-specific effects on cortical cytoarchitecture and impaired the physiological balance between excitatory and inhibitory neurotransmission. These structural changes may underlie the electrophysiological and behavioral effects of prenatal cocaine exposure observed in animal models and human subjects. Copyright © 2012 S. Karger AG, Basel.

Hypothyroidism coordinately and transiently affects myelin protein gene expression in most rat brain regions during postnatal development.

PubMed

Ibarrola, N; Rodríguez-Peña, A

1997-03-28

To assess the role of thyroid hormone on myelin gene expression, we have studied the effect of hypothyroidism on the mRNA steady state levels for the major myelin protein genes: myelin basic protein (MBP), proteolipid protein (PLP), myelin-associated glycoprotein (MAG) and 2':3'-cyclic nucleotide 3'-phosphodiesterase (CNP) in different rat brain regions, during the first postnatal month. We found that hypothyroidism reduces the levels of every myelin protein transcript, with striking differences between the different brain regions. Thus, in the more caudal regions, the effect of hypothyroidism was extremely modest, being only evident at the earlier stages of myelination. In contrast, in the striatum and the cerebral cortex the important decrease in the myelin protein transcripts is maintained beyond the first postnatal month. Therefore, thyroid hormone modulates in a synchronous fashion the expression of the myelin genes and the length of its effect depends on the brain region. On the other hand, hyperthyroidism leads to an increase of the major myelin protein transcripts above control values. Finally, lack of thyroid hormone does not change the expression of the oligodendrocyte progenitor-specific gene, the platelet derived growth factor receptor alpha.

Critical period revisited: impact on vision.

PubMed

Morishita, Hirofumi; Hensch, Takao K

2008-02-01

Neural circuits are shaped by experience in early postnatal life. The permanent loss of visual acuity (amblyopia) and anatomical remodeling within primary visual cortex following monocular deprivation is a classic example of critical period development from mouse to man. Recent work in rodents reveals a residual subthreshold potentiation of open eye response throughout life. Resetting excitatory-inhibitory balance or removing molecular 'brakes' on structural plasticity may unmask the potential for recovery of function in adulthood. Novel pharmacological or environmental interventions now hold great therapeutic promise based on a deeper understanding of critical period mechanisms.

Early life stress-induced alterations in rat brain structures measured with high resolution MRI.

PubMed

Sarabdjitsingh, R Angela; Loi, Manila; Joëls, Marian; Dijkhuizen, Rick M; van der Toorn, Annette

2017-01-01

Adverse experiences early in life impair cognitive function both in rodents and humans. In humans this increases the vulnerability to develop mental illnesses while in the rodent brain early life stress (ELS) abnormalities are associated with changes in synaptic plasticity, excitability and microstructure. Detailed information on the effects of ELS on rodent brain structural integrity at large and connectivity within the brain is currently lacking; this information is highly relevant for understanding the mechanism by which early life stress predisposes to mental illnesses. Here, we exposed rats to 24 hours of maternal deprivation (MD) at postnatal day 3, a paradigm known to increase corticosterone levels and thereby activate glucocorticoid receptors in the brain. Using structural magnetic resonance imaging we examined: i) volumetric changes and white/grey matter properties of the whole cerebrum and of specific brain areas; and ii) whether potential alterations could be normalized by blocking glucocorticoid receptors with mifepristone during the critical developmental window of early adolescence, i.e. between postnatal days 26 and 28. The results show that MD caused a volumetric reduction of the prefrontal cortex, particularly the ventromedial part, and the orbitofrontal cortex. Within the whole cerebrum, white (relative to grey) matter volume was decreased and region-specifically in prefrontal cortex and dorsomedial striatum following MD. A trend was found for the hippocampus. Grey matter fractions were not affected. Treatment with mifepristone did not normalize these changes. This study indicates that early life stress in rodents has long lasting consequences for the volume and structural integrity of the brain. However, changes were relatively modest and-unlike behavior- not mitigated by blockade of glucocorticoid receptors during a critical developmental period.

Prenatal and Early Postnatal Environmental Enrichment Reduce Acute Cell Death and Prevent Neurodevelopment and Memory Impairments in Rats Submitted to Neonatal Hypoxia Ischemia.

PubMed

Durán-Carabali, L E; Arcego, D M; Odorcyk, F K; Reichert, L; Cordeiro, J L; Sanches, E F; Freitas, L D; Dalmaz, C; Pagnussat, A; Netto, C A

2018-05-01

Environmental enrichment (EE) is an experimental strategy to attenuate the negative effects of different neurological conditions including neonatal hypoxia ischemia encephalopathy (HIE). The aim of the present study was to investigate the influence of prenatal and early postnatal EE in animals submitted to neonatal HIE model at postnatal day (PND) 3. Wistar rats were housed in EE or standard conditions (SC) during pregnancy and lactation periods. Pups of both sexes were assigned to one of four experimental groups, considering the early environmental conditions and the injury: SC-Sham, SC-HIE, EE-sham, and EE-HIE. The offspring were euthanized at two different time points: 48 h after HIE for biochemical analyses or at PND 67 for histological analyses. Behavioral tests were performed at PND 7, 14, 21, and 60. Offspring from EE mothers had better performance in neurodevelopmental and spatial memory tests when compared to the SC groups. HIE animals showed a reduction of IGF-1 and VEGF in the parietal cortex, but no differences in BDNF and TrkB levels were found. EE-HIE animals showed reduction in cell death, lower astrocyte reactivity, and an increase in AKTp levels in the hippocampus and parietal cortex. In addition, the EE was also able to prevent the hippocampus tissue loss. Altogether, present findings point to the protective potential of the prenatal and early postnatal EE in attenuating molecular and histological damage, as well as the neurodevelopmental impairments and the cognitive deficit, caused by HIE insult at PND 3.

Sex-specific effects of early life stress on social interaction and prefrontal cortex dendritic morphology in young rats.

PubMed

Farrell, M R; Holland, F H; Shansky, R M; Brenhouse, H C

2016-09-01

Early life stress has been linked to depression, anxiety, and behavior disorders in adolescence and adulthood. The medial prefrontal cortex (mPFC) is implicated in stress-related psychopathology, is a target for stress hormones, and mediates social behavior. The present study investigated sex differences in early-life stress effects on juvenile social interaction and adolescent mPFC dendritic morphology in rats using a maternal separation (MS) paradigm. Half of the rat pups of each sex were separated from their mother for 4h a day between postnatal days 2 and 21, while the other half remained with their mother in the animal facilities and were exposed to minimal handling. At postnatal day 25 (P25; juvenility), rats underwent a social interaction test with an age and sex matched conspecific. Distance from conspecific, approach and avoidance behaviors, nose-to-nose contacts, and general locomotion were measured. Rats were euthanized at postnatal day 40 (P40; adolescence), and randomly selected infralimbic pyramidal neurons were filled with Lucifer yellow using iontophoretic microinjections, imaged in 3D, and then analyzed for dendritic arborization, spine density, and spine morphology. Early-life stress increased the latency to make nose-to-nose contact at P25 in females but not males. At P40, early-life stress increased infralimbic apical dendritic branch number and length and decreased thin spine density in stressed female rats. These results indicate that MS during the postnatal period influenced juvenile social behavior and mPFC dendritic arborization in a sex-specific manner. Copyright © 2016 Elsevier B.V. All rights reserved.

S-adenosyl methionine prevents ASD like behaviors triggered by early postnatal valproic acid exposure in very young mice.

PubMed

Ornoy, Asher; Weinstein-Fudim, Liza; Tfilin, Matanel; Ergaz, Zivanit; Yanai, Joseph; Szyf, Moshe; Turgeman, Gadi

2018-01-16

A common animal model of ASD is the one induced by valproic acid (VPA), inducing epigenetic changes and oxidative stress. We studied the possible preventive effect of the methyl donor for epigenetic enzymatic reactions, S-adenosine methionine (SAM), on ASD like behavioral changes and on redox potential in the brain and liver in this model. ICR albino mice were injected on postnatal day 4 with one dose of 300 mg/kg of VPA, with normal saline (controls) or with VPA and SAM that was given orally for 3 days at the dose of 30 mg/kg body weight. From day 50, we carried out neurobehavioral tests and assessment of the antioxidant status of the prefrontal cerebral cortex, liver assessing SOD and CAT activity, lipid peroxidation and the expression of antioxidant genes. Mice injected with VPA exhibited neurobehavioral deficits typical of ASD that were more prominent in males. Changes in the activity of SOD and CAT increased lipid peroxidation and changes in the expression of antioxidant genes were observed in the prefrontal cortex of VPA treated mice, more prominent in females, while ASD like behavior was more prominent in males. There were no changes in the redox potential of the liver. The co-administration of VPA and SAM alleviated most ASD like neurobehavioral symptoms and normalized the redox potential in the prefrontal cortex. Early postnatal VPA administration induces ASD like behavior that is more severe in males, while the redox status changes are more severe in females; SAM corrects both. VPA-induced ASD seems to result from epigenetic changes, while the redox status changes may be secondary. Copyright © 2018. Published by Elsevier Inc.

Moderate perinatal thyroid hormone insufficiency alters visual system function in adult rats.

PubMed

Boyes, William K; Degn, Laura; George, Barbara Jane; Gilbert, Mary E

2018-04-21

Thyroid hormone (TH) is critical for many aspects of neurodevelopment and can be disrupted by a variety of environmental contaminants. Sensory systems, including audition and vision are vulnerable to TH insufficiencies, but little data are available on visual system development at less than severe levels of TH deprivation. The goal of the current experiments was to explore dose-response relations between graded levels of TH insufficiency during development and the visual function of adult offspring. Pregnant Long Evans rats received 0 or 3 ppm (Experiment 1), or 0, 1, 2, or 3 ppm (Experiment 2) of propylthiouracil (PTU), an inhibitor of thyroid hormone synthesis, in drinking water from gestation day (GD) 6 to postnatal day (PN) 21. Treatment with PTU caused dose-related reductions of serum T4, with recovery on termination of exposure, and euthyroidism by the time of visual function testing. Tests of retinal (electroretinograms; ERGs) and visual cortex (visual evoked potentials; VEPs) function were assessed in adult offspring. Dark-adapted ERG a-waves, reflecting rod photoreceptors, were increased in amplitude by PTU. Light-adapted green flicker ERGs, reflecting M-cone photoreceptors, were reduced by PTU exposure. UV-flicker ERGs, reflecting S-cones, were not altered. Pattern-elicited VEPs were significantly reduced by 2 and 3 ppm PTU across a range of stimulus contrast values. The slope of VEP amplitude-log contrast functions was reduced by PTU, suggesting impaired visual contrast gain. Visual contrast gain primarily reflects function of visual cortex, and is responsible for adjusting sensitivity of perceptual mechanisms in response to changing visual scenes. The results indicate that moderate levels of pre-and post-natal TH insufficiency led to alterations in visual function of adult rats, including both retinal and visual cortex sites of dysfunction. Copyright © 2018. Published by Elsevier B.V.

Expression of small cytoplasmic transcripts of the rat identifier element in vivo and in cultured cells.

PubMed Central

McKinnon, R D; Danielson, P; Brow, M A; Bloom, F E; Sutcliffe, J G

1987-01-01

We examined the level of expression of small RNA transcripts hybridizing to a rodent repetitive DNA element, the identifier (ID) sequence, in a variety of cell types in vivo and in cultured mammalian cells. A 160-nucleotide (160n) cytoplasmic poly(A)+ RNA (BC1) appeared in late embryonic and early postnatal rat brain development, was enriched in the cerebral cortex, and appeared to be restricted to neural tissue and the anterior pituitary gland. A 110n RNA (BC2) was specifically enriched in brain, especially the postnatal cortex, but was detectable at low levels in peripheral tissues. A third, related 75n poly(A)- RNA (T3) was found in rat brain and at lower levels in peripheral tissues but was very abundant in the testes. The BC RNAs were found in a variety of rat cell lines, and their level of expression was dependent upon cell culture conditions. A rat ID probe detected BC-like RNAs in mouse brain but not liver and detected a 200n RNA in monkey brain but not liver at lower hybridization stringencies. These RNAs were expressed by mouse and primate cell lines. Thus, tissue-specific expression of small ID-sequence-related transcripts is conserved among mammals, but the tight regulation found in vivo is lost by cells in culture. Images PMID:2439903

Genetic Elimination of GABAergic Neurotransmission Reveals Two Distinct Pacemakers for Spontaneous Waves of Activity in the Developing Mouse Cortex

PubMed Central

Easton, Curtis R.; Weir, Keiko; Scott, Adina; Moen, Samantha P.; Barger, Zeke; Folch, Albert; Hevner, Robert F.

2014-01-01

Many structures of the mammalian CNS generate propagating waves of electrical activity early in development. These waves are essential to CNS development, mediating a variety of developmental processes, such as axonal outgrowth and pathfinding, synaptogenesis, and the maturation of ion channel and receptor properties. In the mouse cerebral cortex, waves of activity occur between embryonic day 18 and postnatal day 8 and originate in pacemaker circuits in the septal nucleus and the piriform cortex. Here we show that genetic knock-out of the major synthetic enzyme for GABA, GAD67, selectively eliminates the picrotoxin-sensitive fraction of these waves. The waves that remain in the GAD67 knock-out have a much higher probability of propagating into the dorsal neocortex, as do the picrotoxin-resistant fraction of waves in controls. Field potential recordings at the point of wave initiation reveal different electrical signatures for GABAergic and glutamatergic waves. These data indicate that: (1) there are separate GABAergic and glutamatergic pacemaker circuits within the piriform cortex, each of which can initiate waves of activity; (2) the glutamatergic pacemaker initiates waves that preferentially propagate into the neocortex; and (3) the initial appearance of the glutamatergic pacemaker does not require preceding GABAergic waves. In the absence of GAD67, the electrical activity underlying glutamatergic waves shows greatly increased tendency to burst, indicating that GABAergic inputs inhibit the glutamatergic pacemaker, even at stages when GABAergic pacemaker circuitry can itself initiate waves. PMID:24623764

Lrp5/6 are required for cerebellar development and for suppressing TH expression in Purkinje cells via β-catenin.

PubMed

Huang, Ying; Zhang, Qiong; Song, Ning-Ning; Zhang, Lei; Sun, Yu-Ling; Hu, Ling; Chen, Jia-Ying; Zhu, Weidong; Li, Jue; Ding, Yu-Qiang

2016-01-15

The cerebellum is responsible for coordinating motor functions and has a unique laminated architecture. Purkinje cells are inhibitory neurons and represent the only output from the cerebellar cortex. Tyrosine hydroxylase (TH) is the key enzyme for the synthesis of catecholamines, including dopamine and noradrenaline, and it is normally not expressed in cerebellar neurons. We report here that the low-density lipoprotein receptors (Lrp) 5 and 6, Wnt co-receptors, are required for the development of the cerebellum and for suppressing ectopic TH expression in Purkinje cells. Simultaneous inactivation of Lrp 5 and 6 by Nestin-Cre results in defective lamination and foliation of the cerebellum during postnatal development. Surprisingly, TH is ectopically expressed by Purkinje cells, although they still keep its other neurochemical characteristics. These phenotypes are also observed in the cerebellum of GFAP-Cre;β-catenin(flox/flox) mice, and AAV2-Cre-mediated gene deletion leads to ectopic TH expression in Purkinje cells of β-catenin(flox/flox) mice as well. Our results revealed a new role of the canonical Lrp5/6-β-catenin pathway in regulating the morphogenesis of the cerebellum during postnatal development.

GABAergic Inhibition in Visual Cortical Plasticity

PubMed Central

Sale, Alessandro; Berardi, Nicoletta; Spolidoro, Maria; Baroncelli, Laura; Maffei, Lamberto

2010-01-01

Experience is required for the shaping and refinement of developing neural circuits during well defined periods of early postnatal development called critical periods. Many studies in the visual cortex have shown that intracortical GABAergic circuitry plays a crucial role in defining the time course of the critical period for ocular dominance plasticity. With the end of the critical period, neural plasticity wanes and recovery from the effects of visual defects on visual acuity (amblyopia) or binocularity is much reduced or absent. Recent results pointed out that intracortical inhibition is a fundamental limiting factor for adult cortical plasticity and that its reduction by means of different pharmacological and environmental strategies makes it possible to greatly enhance plasticity in the adult visual cortex, promoting ocular dominance plasticity and recovery from amblyopia. Here we focus on the role of intracortical GABAergic circuitry in controlling both developmental and adult cortical plasticity. We shall also discuss the potential clinical application of these findings to neurological disorders in which synaptic plasticity is compromised because of excessive intracortical inhibition. PMID:20407586

Integrative Analysis of Disease Signatures Shows Inflammation Disrupts Juvenile Experience-Dependent Cortical Plasticity

PubMed Central

Smith, Milo R.; Burman, Poromendro

2016-01-01

Throughout childhood and adolescence, periods of heightened neuroplasticity are critical for the development of healthy brain function and behavior. Given the high prevalence of neurodevelopmental disorders, such as autism, identifying disruptors of developmental plasticity represents an essential step for developing strategies for prevention and intervention. Applying a novel computational approach that systematically assessed connections between 436 transcriptional signatures of disease and multiple signatures of neuroplasticity, we identified inflammation as a common pathological process central to a diverse set of diseases predicted to dysregulate plasticity signatures. We tested the hypothesis that inflammation disrupts developmental cortical plasticity in vivo using the mouse ocular dominance model of experience-dependent plasticity in primary visual cortex. We found that the administration of systemic lipopolysaccharide suppressed plasticity during juvenile critical period with accompanying transcriptional changes in a particular set of molecular regulators within primary visual cortex. These findings suggest that inflammation may have unrecognized adverse consequences on the postnatal developmental trajectory and indicate that treating inflammation may reduce the burden of neurodevelopmental disorders. PMID:28101530

Cholinergic systems are essential for late-stage maturation and refinement of motor cortical circuits

PubMed Central

Ramanathan, Dhakshin S.; Conner, James M.; Anilkumar, Arjun A.

2014-01-01

Previous studies reported that early postnatal cholinergic lesions severely perturb early cortical development, impairing neuronal cortical migration and the formation of cortical dendrites and synapses. These severe effects of early postnatal cholinergic lesions preclude our ability to understand the contribution of cholinergic systems to the later-stage maturation of topographic cortical representations. To study cholinergic mechanisms contributing to the later maturation of motor cortical circuits, we first characterized the temporal course of cortical motor map development and maturation in rats. In this study, we focused our attention on the maturation of cortical motor representations after postnatal day 25 (PND 25), a time after neuronal migration has been accomplished and cortical volume has reached adult size. We found significant maturation of cortical motor representations after this time, including both an expansion of forelimb representations in motor cortex and a shift from proximal to distal forelimb representations to an extent unexplainable by simple volume enlargement of the neocortex. Specific cholinergic lesions placed at PND 24 impaired enlargement of distal forelimb representations in particular and markedly reduced the ability to learn skilled motor tasks as adults. These results identify a novel and essential role for cholinergic systems in the late refinement and maturation of cortical circuits. Dysfunctions in this system may constitute a mechanism of late-onset neurodevelopmental disorders such as Rett syndrome and schizophrenia. PMID:25505106

Disorganization of Oligodendrocyte Development in the Layer II/III of the Sensorimotor Cortex Causes Motor Coordination Dysfunction in a Model of White Matter Injury in Neonatal Rats.

PubMed

Ueda, Yoshitomo; Misumi, Sachiyo; Suzuki, Mina; Ogawa, Shino; Nishigaki, Ruriko; Ishida, Akimasa; Jung, Cha-Gyun; Hida, Hideki

2018-01-01

We previously established neonatal white matter injury (WMI) model rat that is made by right common carotid artery dissection at postnatal day 3, followed by 6% hypoxia for 60 min. This model has fewer oligodendrocyte progenitor cells and reduced myelin basic protein (MBP) positive areas in the sensorimotor cortex, but shows no apparent neuronal loss. However, how motor deficits are induced in this model is unclear. To elucidate the relationship between myelination disturbance and concomitant motor deficits, we first performed motor function tests (gait analysis, grip test, horizontal ladder test) and then analyzed myelination patterns in the sensorimotor cortex using transmission electron microscopy (TEM) and Contactin associated protein 1 (Caspr) staining in the neonatal WMI rats in adulthood. Behavioral tests revealed imbalanced motor coordination in this model. Motor deficit scores were higher in the neonatal WMI model, while hindlimb ladder stepping scores and forelimb grasping force were comparable to controls. Prolonged forelimb swing times and decreased hindlimb paw angles on the injured side were revealed by gait analysis. TEM revealed no change in myelinated axon number and the area g-ratio in the layer II/III of the cortex. Electromyographical durations and latencies in the gluteus maximus in response to electrical stimulation of the brain area were unchanged in the model. Caspr staining revealed fewer positive dots in layers II/III of the WMI cortex, indicating fewer and/or longer myelin sheath. These data suggest that disorganization of oligodendrocyte development in layers II/III of the sensorimotor cortex relates to imbalanced motor coordination in the neonatal WMI model rat.

Extended Plasticity of Visual Cortex in Dark-Reared Animals May Result from Prolonged Expression of cpg15-Like Genes

PubMed Central

Lee, Wei-Chung Allen; Nedivi, Elly

2011-01-01

cpg15 is an activity-regulated gene that encodes a membrane-bound ligand that coordinately regulates growth of apposing dendritic and axonal arbors and the maturation of their synapses. These properties make it an attractive candidate for participating in plasticity of the mammalian visual system. Here we compare cpg15 expression during normal development of the rat visual system with that seen in response to dark rearing, monocular blockade of retinal action potentials, or monocular deprivation. Our results show that the onset of cpg15 expression in the visual cortex is coincident with eye opening, and it increases until the peak of the critical period at postnatal day 28 (P28). This early expression is independent of both retinal activity and visual experience. After P28, a component of cpg15 expression in the visual cortex, lateral geniculate nucleus (LGN), and superior colliculus (SC) develops a progressively stronger dependence on retinally driven action potentials. Dark rearing does not affect cpg15 mRNA expression in the LGN and SC at any age, but it does significantly affect its expression in the visual cortex from the peak of the critical period and into adulthood. In dark-reared rats, the peak level of cpg15 expression in the visual cortex at P28 is lower than in controls. Rather than showing the normal decline with maturation, these levels are maintained in dark-reared animals. We suggest that the prolonged plasticity in the visual cortex that is seen in dark-reared animals may result from failure to downregulate genes such as cpg15 that could promote structural remodeling and synaptic maturation. PMID:11880509

Expression of glucocorticoid receptor and early growth response gene 1 during postnatal development of two inbred strains of mice exposed to early life stress.

PubMed

Navailles, Sylvia; Zimnisky, Ross; Schmauss, Claudia

2010-07-01

Early life stress can elicit profound changes in adult gene expression and behavior. One consequence of early life stress is a decreased expression of glucocorticoid receptors (GRs) in the frontal cortex and hippocampus. However, neither the time of onset nor the mechanism(s) leading to decreased GR expression during postnatal development are known. The present study used two inbred strains of mice that differ in their behavioral responsiveness to stress (Balb/c and C57Bl/6), exposed them to an established paradigm of early life stress (infant maternal separation), and measured their expression of frontal cortical and hippocampal GRs and the putative transcriptional activator of the GR gene, early growth response gene (egr)-1, at defined stages of postnatal development. In both strains, real-time RT-PCR experiments revealed that decreased expression of GR in adolescence and adulthood is, in fact, preceded by increased GR expression during early life stress exposure. Thus, the early life stress-induced disruption of the normal stress-hyporesponsive period during infancy is accompanied by increased GR expression. Moreover, chronic treatment with the antidepressant drug fluoxetine during adolescence or adulthood reversed the effect of early life stress on adult GR mRNA expression. In contrast to the strain-independent effect of early life stress on GR expression, however, changes in egr-1 expression occurred only in Balb/c mice, and unlike the biphasic developmental changes in GR mRNA expression, egr-1 mRNA was decreased throughout postnatal development. Moreover, there was no consistent overlap of anatomic regions affected by decreased GR and egr-1 protein expression. Thus, in Balb/c mice, changes in GR and egr-1 expression can independently contribute to the phenotypes resulting from early life stress exposure. These findings illustrate that the impact of early life stress on gene expression changes is modulated by the genetic background and that the persistent changes in GR and egr-1 expression that arise early during postnatal developmental are reversible by chronic fluoxetine treatment during adolescence and adulthood. Copyright 2010 S. Karger AG, Basel.

Role of interstitial branching in the development of visual corticocortical connections: a time-lapse and fixed-tissue analysis.

PubMed

Ruthazer, Edward S; Bachleda, Amelia R; Olavarria, Jaime F

2010-12-15

We combined fixed-tissue and time-lapse analyses to investigate the axonal branching phenomena underlying the development of topographically organized ipsilateral projections from area 17 to area 18a in the rat. These complementary approaches allowed us to relate static, large-scale information provided by traditional fixed-tissue analysis to highly dynamic, local, small-scale branching phenomena observed with two-photon time-lapse microscopy in acute slices of visual cortex. Our fixed-tissue data revealed that labeled area 17 fibers invaded area 18a gray matter at topographically restricted sites, reaching superficial layers in significant numbers by postnatal day 6 (P6). Moreover, most parental axons gave rise to only one or occasionally a small number of closely spaced interstitial branches beneath 18a. Our time-lapse data showed that many filopodium-like branches emerged along parental axons in white matter or deep layers in area 18a. Most of these filopodial branches were transient, often disappearing after several minutes to hours of exploratory extension and retraction. These dynamic behaviors decreased significantly from P4, when the projection is first forming, through the second postnatal week, suggesting that the expression of, or sensitivity to, cortical cues promoting new branch addition in the white matter is developmentally down-regulated coincident with gray matter innervation. Together, these data demonstrate that the development of topographically organized corticocortical projections in rats involves extensive exploratory branching along parental axons and invasion of cortex by only a small number of interstitial branches, rather than the widespread innervation of superficial cortical layers by an initially exuberant population of branches. © 2010 Wiley-Liss, Inc.

Glycogen synthase kinase-3 levels and phosphorylation undergo large fluctuations in mouse brain during development

PubMed Central

Beurel, Eléonore; Mines, Marjelo A; Song, Ling; Jope, Richard S

2012-01-01

Objectives Dysregulated glycogen synthase kinase-3 (GSK3) may contribute to the pathophysiology of mood disorders and other diseases, and appears to be a target of certain therapeutic drugs. The growing recognition of heightened vulnerability during development to many psychiatric diseases, including mood disorders, led us to test if there are developmental changes in mouse brain GSK3 and its regulation by phosphorylation and by therapeutic drugs. Methods GSK3 levels and phosphorylation were measured at seven ages of development in mouse cerebral cortex and hippocampus. Results Two periods of rapid transitions in GSK3 levels were identified, a large rise between postnatal day 1 and two to three weeks of age, where GSK3 levels were as high as four-fold adult mouse brain levels, and a rapid decline between two to four and eight weeks of age, when adult levels were reached. Inhibitory serine-phosphorylation of GSK3, particularly GSK3β, was extremely high in one-day postnatal mouse brain, and rapidly declined thereafter. These developmental changes in GSK3 were equivalent in male and female cerebral cortex, and differed from other signaling kinases, including Akt, ERK1/2, JNK, and p38 levels and phosphorylation. In contrast to adult mouse brain, where administration of lithium or fluoxetine rapidly and robustly increased serine-phosphorylation of GSK3, in young mice these responses were blunted or absent. Conclusions High brain levels of GSK3 and large fluctuations in its levels and phosphorylation in juvenile and adolescent mouse brain raise the possibility that they may contribute to destabilized mood regulation induced by environmental and genetic factors. PMID:23167932

Absence of Colony Stimulation Factor-1 Receptor Results in Loss of Microglia, Disrupted Brain Development and Olfactory Deficits

PubMed Central

Etgen, Anne M.; Dobrenis, Kostantin; Pollard, Jeffrey W.

2011-01-01

The brain contains numerous mononuclear phagocytes called microglia. These cells express the transmembrane tyrosine kinase receptor for the macrophage growth factor colony stimulating factor-1 (CSF-1R). Using a CSF-1R-GFP reporter mouse strain combined with lineage defining antibody staining we show in the postnatal mouse brain that CSF-1R is expressed only in microglia and not neurons, astrocytes or glial cells. To study CSF-1R function we used mice homozygous for a null mutation in the Csflr gene. In these mice microglia are >99% depleted at embryonic day 16 and day 1 post-partum brain. At three weeks of age this microglial depletion continues in most regions of the brain although some contain clusters of rounded microglia. Despite the loss of microglia, embryonic brain development appears normal but during the post-natal period the brain architecture becomes perturbed with enlarged ventricles and regionally compressed parenchyma, phenotypes most prominent in the olfactory bulb and cortex. In the cortex there is increased neuronal density, elevated numbers of astrocytes but reduced numbers of oligodendrocytes. Csf1r nulls rarely survive to adulthood and therefore to study the role of CSF-1R in olfaction we used the viable null mutants in the Csf1 (Csf1op) gene that encodes one of the two known CSF-1R ligands. Food-finding experiments indicate that olfactory capacity is significantly impaired in the absence of CSF-1. CSF-1R is therefore required for the development of microglia, for a fully functional olfactory system and the maintenance of normal brain structure. PMID:22046273

Role of Interstitial Branching in the Development of Visual Corticocortical Connections: A Time-Lapse and Fixed-Tissue Analysis

PubMed Central

Ruthazer, Edward S.; Bachleda, Amelia R.; Olavarria, Jaime F.

2013-01-01

We combined fixed-tissue and time-lapse analyses to investigate the axonal branching phenomena underlying the development of topographically organized ipsilateral projections from area 17 to area 18a in the rat. These complementary approaches allowed us to relate static, large-scale information provided by traditional fixed-tissue analysis to highly dynamic, local, small-scale branching phenomena observed with two-photon time-lapse microscopy in acute slices of visual cortex. Our fixed-tissue data revealed that labeled area 17 fibers invaded area 18a gray matter at topographically restricted sites, reaching superficial layers in significant numbers by postnatal day 6 (P6). Moreover, most parental axons gave rise to only one or occasionally a small number of closely spaced interstitial branches beneath 18a. Our time-lapse data showed that many filopodium-like branches emerged along parental axons in white matter or deep layers in area 18a. Most of these filopo-dial branches were transient, often disappearing after several minutes to hours of exploratory extension and retraction. These dynamic behaviors decreased significantly from P4, when the projection is first forming, through the second postnatal week, suggesting that the expression of, or sensitivity to, cortical cues promoting new branch addition in the white matter is developmentally down-regulated coincident with gray matter innervation. Together, these data demonstrate that the development of topographically organized corticocortical projections in rats involves extensive exploratory branching along parental axons and invasion of cortex by only a small number of interstitial branches, rather than the widespread innervation of superficial cortical layers by an initially exuberant population of branches. PMID:21031561

Losing the sugar coating: potential impact of perineuronal net abnormalities on interneurons in schizophrenia.

PubMed

Berretta, Sabina; Pantazopoulos, Harry; Markota, Matej; Brown, Christopher; Batzianouli, Eleni T

2015-09-01

Perineuronal nets (PNNs) were shown to be markedly altered in subjects with schizophrenia. In particular, decreases of PNNs have been detected in the amygdala, entorhinal cortex and prefrontal cortex. The formation of these specialized extracellular matrix (ECM) aggregates during postnatal development, their functions, and association with distinct populations of GABAergic interneurons, bear great relevance to the pathophysiology of schizophrenia. PNNs gradually mature in an experience-dependent manner during late stages of postnatal development, overlapping with the prodromal period/age of onset of schizophrenia. Throughout adulthood, PNNs regulate neuronal properties, including synaptic remodeling, cell membrane compartmentalization and subsequent regulation of glutamate receptors and calcium channels, and susceptibility to oxidative stress. With the present paper, we discuss evidence for PNN abnormalities in schizophrenia, the potential functional impact of such abnormalities on inhibitory circuits and, in turn, cognitive and emotion processing. We integrate these considerations with results from recent genetic studies showing genetic susceptibility for schizophrenia associated with genes encoding for PNN components, matrix-regulating molecules and immune system factors. Notably, the composition of PNNs is regulated dynamically in response to factors such as fear, reward, stress, and immune response. This regulation occurs through families of matrix metalloproteinases that cleave ECM components, altering their functions and affecting plasticity. Several metalloproteinases have been proposed as vulnerability factors for schizophrenia. We speculate that the physiological process of PNN remodeling may be disrupted in schizophrenia as a result of interactions between matrix remodeling processes and immune system dysregulation. In turn, these mechanisms may contribute to the dysfunction of GABAergic neurons. Copyright © 2015. Published by Elsevier B.V.

Alterations of resting state networks and structural connectivity in relation to the prefrontal and anterior cingulate cortices in late prematurity.

PubMed

Degnan, Andrew J; Wisnowski, Jessica L; Choi, SoYoung; Ceschin, Rafael; Bhushan, Chitresh; Leahy, Richard M; Corby, Patricia; Schmithorst, Vincent J; Panigrahy, Ashok

2015-01-07

Late preterm birth is increasingly recognized as a risk factor for cognitive and social deficits. The prefrontal cortex is particularly vulnerable to injury in late prematurity because of its protracted development and extensive cortical connections. Our study examined children born late preterm without access to advanced postnatal care to assess structural and functional connectivity related to the prefrontal cortex. Thirty-eight preadolescents [19 born late preterm (34-36 /7 weeks gestational age) and 19 at term] were recruited from a developing community in Brazil. Participants underwent neuropsychological testing. Individuals underwent three-dimensional T1-weighted, diffusion-weighted, and resting state functional MRI. Probabilistic tractography and functional connectivity analyses were carried out using unilateral seeds combining the medial prefrontal cortex and the anterior cingulate cortex. Late preterm children showed increased functional connectivity within regions of the default mode, salience, and central-executive networks from both right and left frontal cortex seeds. Decreased functional connectivity was observed within the right parahippocampal region from left frontal seeding. Probabilistic tractography showed a pattern of decreased streamlines in frontal white matter pathways and the corpus callosum, but also increased streamlines in the left orbitofrontal white matter and the right frontal white matter when seeded from the right. Late preterm children and term control children scored similarly on neuropsychological testing. Prefrontal cortical connectivity is altered in late prematurity, with hyperconnectivity observed in key resting state networks in the absence of neuropsychological deficits. Abnormal structural connectivity indicated by probabilistic tractography suggests subtle changes in white matter development, implying disruption of normal maturation during the late gestational period.

Laminar distribution of cholinergic- and serotonergic-dependent plasticity within kitten visual cortex.

PubMed

Kojic, L; Gu, Q; Douglas, R M; Cynader, M S

2001-02-28

Both cholinergic and serotonergic modulatory projections to mammalian striate cortex have been demonstrated to be involved in the regulation of postnatal plasticity, and a striking alteration in the number and intracortical distribution of cholinergic and serotonergic receptors takes place during the critical period for cortical plasticity. As well, agonists of cholinergic and serotonergic receptors have been demonstrated to facilitate induction of long-term synaptic plasticity in visual cortical slices supporting their involvement in the control of activity-dependent plasticity. We recorded field potentials from layers 4 and 2/3 in visual cortex slices of 60--80 day old kittens after white matter stimulation, before and after a period of high frequency stimulation (HFS), in the absence or presence of either cholinergic or serotonergic agonists. At these ages, the HFS protocol alone almost never induced long-term changes of synaptic plasticity in either layers 2/3 or 4. In layer 2/3, agonist stimulation of m1 receptors facilitated induction of long-term potentiation (LTP) with HFS stimulation, while the activation of serotonergic receptors had only a modest effect. By contrast, a strong serotonin-dependent LTP facilitation and insignificant muscarinic effects were observed after HFS within layer 4. The results show that receptor-dependent laminar stratification of synaptic modifiability occurs in the cortex at these ages. This plasticity may underly a control system gating the experience-dependent changes of synaptic organization within developing visual cortex.

Postnatal Maturation of the Red Nucleus Motor Map Depends on Rubrospinal Connections with Forelimb Motor Pools

PubMed Central

Williams, Preston T. J. A.; Kim, Sangsoo

2014-01-01

The red nucleus (RN) and rubrospinal tract (RST) are important for forelimb motor control. Although the RST is present postnatally in cats, nothing is known about when rubrospinal projections could support motor functions or the relation between the development of the motor functions of the rubrospinal system and the corticospinal system, the other major system for limb control. Our hypothesis is that the RN motor map is present earlier in development than the motor cortex (M1) map, to support early forelimb control. We investigated RN motor map maturation with microstimulation and RST cervical enlargement projections using anterograde tracers between postnatal week 3 (PW3) and PW16. Microstimulation and tracer injection sites were verified histologically to be located within the RN. Microstimulation at PW4 evoked contralateral wrist, elbow, and shoulder movements. The number of sites producing limb movement increased and response thresholds decreased progressively through PW16. From the outset, all forelimb joints were represented. At PW3, RST projections were present within the cervical intermediate zone, with a mature density of putative synapses. In contrast, beginning at PW5 there was delayed and age-dependent development of forelimb motor pool projections and putative rubromotoneuronal synapses. The RN has a more complete forelimb map early in development than previous studies showed for M1, supporting our hypothesis of preferential rubrospinal rather than corticospinal control for early movements. Remarkably, development of the motor pool, not intermediate zone, RST projections paralleled RN motor map development. The RST may be critical for establishing the rudiments of motor skills that subsequently become refined with further CST development. PMID:24647962

Distinct Physiological Maturation of Parvalbumin-Positive Neuron Subtypes in Mouse Prefrontal Cortex.

PubMed

Miyamae, Takeaki; Chen, Kehui; Lewis, David A; Gonzalez-Burgos, Guillermo

2017-05-10

Parvalbumin-positive (PV + ) neurons control the timing of pyramidal cell output in cortical neuron networks. In the prefrontal cortex (PFC), PV + neuron activity is involved in cognitive function, suggesting that PV + neuron maturation is critical for cognitive development. The two major PV + neuron subtypes found in the PFC, chandelier cells (ChCs) and basket cells (BCs), are thought to play different roles in cortical circuits, but the trajectories of their physiological maturation have not been compared. Using two separate mouse lines, we found that in the mature PFC, both ChCs and BCs are abundant in superficial layer 2, but only BCs are present in deeper laminar locations. This distinctive laminar distribution was observed by postnatal day 12 (P12), when we first identified ChCs by the presence of axon cartridges. Electrophysiology analysis of excitatory synapse development, starting at P12, showed that excitatory drive remains low throughout development in ChCs, but increases rapidly before puberty in BCs, with an earlier time course in deeper-layer BCs. Consistent with a role of excitatory synaptic drive in the maturation of PV + neuron firing properties, the fast-spiking phenotype showed different maturation trajectories between ChCs and BCs, and between superficial versus deep-layer BCs. ChC and BC maturation was nearly completed, via different trajectories, before the onset of puberty. These findings suggest that ChC and BC maturation may contribute differentially to the emergence of cognitive function, primarily during prepubertal development. SIGNIFICANCE STATEMENT Parvalbumin-positive (PV + ) neurons tightly control pyramidal cell output. Thus PV + neuron maturation in the prefrontal cortex (PFC) is crucial for cognitive development. However, the relative physiological maturation of the two major subtypes of PV + neurons, chandelier cells (ChCs) and basket cells (BCs), has not been determined. We assessed the maturation of ChCs and BCs in different layers of the mouse PFC, and found that, from early postnatal age, ChCs and BCs differ in laminar location. Excitatory synapses and fast-spiking properties matured before the onset of puberty in both cell types, but following cell type-specific developmental trajectories. Hence, the physiological maturation of ChCs and BCs may contribute to the emergence of cognitive function differentially, and predominantly during prepubertal development. Copyright © 2017 the authors 0270-6474/17/374883-20$15.00/0.

Perinatal exposure to bisphenol-A impairs spatial memory through upregulation of neurexin1 and neuroligin3 expression in male mouse brain.

PubMed

Kumar, Dhiraj; Thakur, Mahendra Kumar

2014-01-01

Bisphenol-A (BPA), a well known endocrine disruptor, impairs learning and memory in rodents. However, the underlying molecular mechanism of BPA induced impairment in learning and memory is not well known. As synaptic plasticity is the cellular basis of memory, the present study investigated the effect of perinatal exposure to BPA on the expression of synaptic proteins neurexin1 (Nrxn1) and neuroligin3 (Nlgn3), dendritic spine density and spatial memory in postnatal male mice. The pregnant mice were orally administered BPA (50 µg/kgbw/d) from gestation day (GD) 7 to postnatal day (PND) 21 and sesame oil was used as a vehicle control. In Morris water maze (MWM) test, BPA extended the escape latency time to locate the hidden platform in 8 weeks male mice. RT-PCR and Immunoblotting results showed significant upregulation of Nrxn1 and Nlgn3 expression in both cerebral cortex and hippocampus of 3 and 8 weeks male mice. This was further substantiated by in-situ hybridization and immunofluorescence techniques. BPA also significantly increased the density of dendritic spines in both regions, as analyzed by rapid Golgi staining. Thus our data suggest that perinatal exposure to BPA impairs spatial memory through upregulation of expression of synaptic proteins Nrxn1 and Nlgn3 and increased dendritic spine density in cerebral cortex and hippocampus of postnatal male mice.

Perinatal Exposure to Bisphenol-A Impairs Spatial Memory through Upregulation of Neurexin1 and Neuroligin3 Expression in Male Mouse Brain

PubMed Central

Kumar, Dhiraj; Thakur, Mahendra Kumar

2014-01-01

Bisphenol-A (BPA), a well known endocrine disruptor, impairs learning and memory in rodents. However, the underlying molecular mechanism of BPA induced impairment in learning and memory is not well known. As synaptic plasticity is the cellular basis of memory, the present study investigated the effect of perinatal exposure to BPA on the expression of synaptic proteins neurexin1 (Nrxn1) and neuroligin3 (Nlgn3), dendritic spine density and spatial memory in postnatal male mice. The pregnant mice were orally administered BPA (50 µg/kgbw/d) from gestation day (GD) 7 to postnatal day (PND) 21 and sesame oil was used as a vehicle control. In Morris water maze (MWM) test, BPA extended the escape latency time to locate the hidden platform in 8 weeks male mice. RT-PCR and Immunoblotting results showed significant upregulation of Nrxn1 and Nlgn3 expression in both cerebral cortex and hippocampus of 3 and 8 weeks male mice. This was further substantiated by in-situ hybridization and immunofluorescence techniques. BPA also significantly increased the density of dendritic spines in both regions, as analyzed by rapid Golgi staining. Thus our data suggest that perinatal exposure to BPA impairs spatial memory through upregulation of expression of synaptic proteins Nrxn1 and Nlgn3 and increased dendritic spine density in cerebral cortex and hippocampus of postnatal male mice. PMID:25330104

Plasticity in One Hemisphere, Control From Two: Adaptation in Descending Motor Pathways After Unilateral Corticospinal Injury in Neonatal Rats

PubMed Central

Wen, Tong-Chun; Lall, Sophia; Pagnotta, Corey; Markward, James; Gupta, Disha; Ratnadurai-Giridharan, Shivakeshavan; Bucci, Jacqueline; Greenwald, Lucy; Klugman, Madelyne; Hill, N. Jeremy; Carmel, Jason B.

2018-01-01

After injury to the corticospinal tract (CST) in early development there is large-scale adaptation of descending motor pathways. Some studies suggest the uninjured hemisphere controls the impaired forelimb, while others suggest that the injured hemisphere does; these pathways have never been compared directly. We tested the contribution of each motor cortex to the recovery forelimb function after neonatal injury of the CST. We cut the left pyramid (pyramidotomy) of postnatal day 7 rats, which caused a measurable impairment of the right forelimb. We used pharmacological inactivation of each motor cortex to test its contribution to a skilled reach and supination task. Rats with neonatal pyramidotomy were further impaired by inactivation of motor cortex in both the injured and the uninjured hemispheres, while the forelimb of uninjured rats was impaired only from the contralateral motor cortex. Thus, inactivation demonstrated motor control from each motor cortex. In contrast, physiological and anatomical interrogation of these pathways support adaptations only in the uninjured hemisphere. Intracortical microstimulation of motor cortex in the uninjured hemisphere of rats with neonatal pyramidotomy produced responses from both forelimbs, while stimulation of the injured hemisphere did not elicit responses from either forelimb. Both anterograde and retrograde tracers were used to label corticofugal pathways. There was no increased plasticity from the injured hemisphere, either from cortex to the red nucleus or the red nucleus to the spinal cord. In contrast, there were very strong CST connections to both halves of the spinal cord from the uninjured motor cortex. Retrograde tracing produced maps of each forelimb within the uninjured hemisphere, and these were partly segregated. This suggests that the uninjured hemisphere may encode separate control of the unimpaired and the impaired forelimbs of rats with neonatal pyramidotomy. PMID:29706871

Plasticity in One Hemisphere, Control From Two: Adaptation in Descending Motor Pathways After Unilateral Corticospinal Injury in Neonatal Rats.

PubMed

Wen, Tong-Chun; Lall, Sophia; Pagnotta, Corey; Markward, James; Gupta, Disha; Ratnadurai-Giridharan, Shivakeshavan; Bucci, Jacqueline; Greenwald, Lucy; Klugman, Madelyne; Hill, N Jeremy; Carmel, Jason B

2018-01-01

After injury to the corticospinal tract (CST) in early development there is large-scale adaptation of descending motor pathways. Some studies suggest the uninjured hemisphere controls the impaired forelimb, while others suggest that the injured hemisphere does; these pathways have never been compared directly. We tested the contribution of each motor cortex to the recovery forelimb function after neonatal injury of the CST. We cut the left pyramid (pyramidotomy) of postnatal day 7 rats, which caused a measurable impairment of the right forelimb. We used pharmacological inactivation of each motor cortex to test its contribution to a skilled reach and supination task. Rats with neonatal pyramidotomy were further impaired by inactivation of motor cortex in both the injured and the uninjured hemispheres, while the forelimb of uninjured rats was impaired only from the contralateral motor cortex. Thus, inactivation demonstrated motor control from each motor cortex. In contrast, physiological and anatomical interrogation of these pathways support adaptations only in the uninjured hemisphere. Intracortical microstimulation of motor cortex in the uninjured hemisphere of rats with neonatal pyramidotomy produced responses from both forelimbs, while stimulation of the injured hemisphere did not elicit responses from either forelimb. Both anterograde and retrograde tracers were used to label corticofugal pathways. There was no increased plasticity from the injured hemisphere, either from cortex to the red nucleus or the red nucleus to the spinal cord. In contrast, there were very strong CST connections to both halves of the spinal cord from the uninjured motor cortex. Retrograde tracing produced maps of each forelimb within the uninjured hemisphere, and these were partly segregated. This suggests that the uninjured hemisphere may encode separate control of the unimpaired and the impaired forelimbs of rats with neonatal pyramidotomy.

Mild prenatal protein malnutrition increases alpha 2C-adrenoceptor expression in the rat cerebral cortex during postnatal life.

PubMed

Sierralta, Walter; Hernández, Alejandro; Valladares, Luis; Pérez, Hernán; Mondaca, Mauricio; Soto-Moyano, Rubén

2006-05-15

Mild reduction in the protein content in the diet of pregnant rats from 25 to 8% casein, calorically compensated by carbohydrates, does not alter body and brain weights of rat pups at birth, but results in significant changes of the concentration and release of cortical noradrenaline during postnatal life, together with impaired long-term potentiation and memory formation. Since some central noradrenergic receptors are critically involved in neuroplasticity, the present study evaluated, by utilizing immunohistochemical methods, the effect of mild prenatal protein malnutrition on the alpha 2C-adrenoceptor expression in the frontal and occipital cortices of 8- and 60-day-old rats. At day 8 of postnatal age, prenatally malnourished rats exhibited a three-fold increase of alpha 2C-adrenoceptor expression in both the frontal and the occipital cortices, as compared to well-nourished controls. At 60 days of age, prenatally malnourished rats showed normal expression levels scores of alpha 2C-adrenoceptor in the neocortex. Results suggest that overexpression of neocortical alpha 2C-adrenoceptors during early postnatal life, subsequent to mild prenatal protein malnutrition, could in part be responsible for neural and behavioral disturbances showing prenatally malnourished animals during the postnatal life.

JIP3 regulates neuronal radial migration by mediating TrkB axonal anterograde transport in the developing cerebral cortex.

PubMed

Ma, Huixian; Yu, Hui; Li, Ting; Zhao, Yan; Hou, Ming; Chen, Zheyu; Wang, Yue; Sun, Tao

2017-04-15

Radial migration is essential for the precise lamination and the coordinated function of the cerebral cortex. However, the molecular mechanisms for neuronal radial migration are not clear. Here, we report that c-Jun NH2-terminal kinase (JNK)-interacting protein-3 (JIP3) is highly expressed in the brain of embryonic mice and essential for radial migration. Knocking down JIP3 by in utero electroporation specifically perturbs the radial migration of cortical neurons but has no effect on neurogenesis and neuronal differentiation. Furthermore, we illustrate that JIP3 knockdown delays but does not block the migration of cortical neurons by investigating the distribution of neurons with JIP3 knocked down in the embryo and postnatal mouse. Finally, we find that JIP3 regulates cortical neuronal migration by mediating TrkB axonal anterograde transport during brain development. These findings deepen our understanding of the regulation of neuronal development by JIP3 and provide us a novel view on the regulating mechanisms of neuronal radial migration. Copyright © 2017 Elsevier Inc. All rights reserved.

Perinatal exposure to a noncoplanar polychlorinated biphenyl alters tonotopy, receptive fields, and plasticity in rat primary auditory cortex

PubMed Central

Kenet, T.; Froemke, R. C.; Schreiner, C. E.; Pessah, I. N.; Merzenich, M. M.

2007-01-01

Noncoplanar polychlorinated biphenyls (PCBs) are widely dispersed in human environment and tissues. Here, an exemplar noncoplanar PCB was fed to rat dams during gestation and throughout three subsequent nursing weeks. Although the hearing sensitivity and brainstem auditory responses of pups were normal, exposure resulted in the abnormal development of the primary auditory cortex (A1). A1 was irregularly shaped and marked by internal nonresponsive zones, its topographic organization was grossly abnormal or reversed in about half of the exposed pups, the balance of neuronal inhibition to excitation for A1 neurons was disturbed, and the critical period plasticity that underlies normal postnatal auditory system development was significantly altered. These findings demonstrate that developmental exposure to this class of environmental contaminant alters cortical development. It is proposed that exposure to noncoplanar PCBs may contribute to common developmental disorders, especially in populations with heritable imbalances in neurotransmitter systems that regulate the ratio of inhibition and excitation in the brain. We conclude that the health implications associated with exposure to noncoplanar PCBs in human populations merit a more careful examination. PMID:17460041

Postnatal Ablation of Synaptic Retinoic Acid Signaling Impairs Cortical Information Processing and Sensory Discrimination in Mice.

PubMed

Park, Esther; Tjia, Michelle; Zuo, Yi; Chen, Lu

2018-06-06

Retinoic acid (RA) and its receptors (RARs) are well established essential transcriptional regulators during embryonic development. Recent findings in cultured neurons identified an independent and critical post-transcriptional role of RA and RARα in the homeostatic regulation of excitatory and inhibitory synaptic transmission in mature neurons. However, the functional relevance of synaptic RA signaling in vivo has not been established. Here, using somatosensory cortex as a model system and the RARα conditional knock-out mouse as a tool, we applied multiple genetic manipulations to delete RARα postnatally in specific populations of cortical neurons, and asked whether synaptic RA signaling observed in cultured neurons is involved in cortical information processing in vivo Indeed, conditional ablation of RARα in mice via a CaMKIIα-Cre or a layer 5-Cre driver line or via somatosensory cortex-specific viral expression of Cre-recombinase impaired whisker-dependent texture discrimination, suggesting a critical requirement of RARα expression in L5 pyramidal neurons of somatosensory cortex for normal tactile sensory processing. Transcranial two-photon imaging revealed a significant increase in dendritic spine elimination on apical dendrites of somatosensory cortical layer 5 pyramidal neurons in these mice. Interestingly, the enhancement of spine elimination is whisker experience-dependent as whisker trimming rescued the spine elimination phenotype. Additionally, experiencing an enriched environment improved texture discrimination in RARα-deficient mice and reduced excessive spine pruning. Thus, RA signaling is essential for normal experience-dependent cortical circuit remodeling and sensory processing. SIGNIFICANCE STATEMENT The importance of synaptic RA signaling has been demonstrated in in vitro studies. However, whether RA signaling mediated by RARα contributes to neural circuit functions in vivo remains largely unknown. In this study, using a RARα conditional knock-out mouse, we performed multiple regional/cell-type-specific manipulation of RARα expression in the postnatal brain, and show that RARα signaling contributes to normal whisker-dependent texture discrimination as well as regulating spine dynamics of apical dendrites from layer (L5) pyramidal neurons in S1. Deletion of RARα in excitatory neurons in the forebrain induces elevated spine elimination and impaired sensory discrimination. Our study provides novel insights into the role of RARα signaling in cortical processing and experience-dependent spine maturation. Copyright © 2018 the authors 0270-6474/18/385277-12$15.00/0.

Impact of propofol anaesthesia on cytokine expression profiles in the developing rat brain: a randomised placebo-controlled experimental in-vivo study.

PubMed

Kargaran, Parichehr; Lenglet, Sébastien; Montecucco, Fabrizio; Mach, François; Copin, Jean-Christophe; Vutskits, Laszlo

2015-05-01

Recent experimental data indicate that volatile anaesthetics can induce a neuroinflammatory response in the central nervous system. The questions of to what extent this occurs in the developing brain and whether nonvolatile anaesthetics are also involved remain unanswered. The objective of this study is to investigate the impact of propofol anaesthesia on cytokine mRNA expression profiles in the neonatal brain at defined stages of the brain growth spurt. A randomised placebo-controlled experimental in-vivo study. Translational research laboratories at the University of Geneva Medical School. Wistar rats received 6-h propofol anaesthesia at postnatal day 10 or 20. A quantitative real-time PCR was used to evaluate the impact of this treatment paradigm on mRNA expression profiles of selected members of the cytokine family in the prefrontal cortex and hippocampus. Propofol anaesthesia induced a transient 1.8-fold (interquartile range, IQR 1.7 to 2.2) increase (P = 0.004) in prefrontal but not hippocampal tumour necrosis factor mRNA concentrations in 10-day-old animals. No such effect was detected in 20-day-old animals. No changes in mRNA concentrations of two other pro-inflammatory cytokines, interleukins IL-6 and IL-1β, were detected following drug exposure at any developmental stages or in any studied brain regions. In contrast, propofol anaesthesia at postnatal day 10 induced a transient increase in the mRNA expression patterns of two chemokines: Ccl2 and Ccl3 [for Ccl2 mRNA: 4.4-fold (3.8 to 5.6) increase in the prefrontal cortex, P = 0.0002 and a 3.5-fold (2.8 to 5.3) increase in the hippocampus, P = 0.0001; for Ccl3 mRNA: 2.9-fold (2.6 to 4.31) increase in the prefrontal cortex, P = 0.0001, and a 2.7-fold (2.2 to 3.6) increase in the hippocampus, P = 0.0003]. Propofol did not affect Ccl2 and Ccl3 mRNA concentrations in 20-day-old animals. In addition, it did not impact on two other members of the chemokine family, Cxcl1 and Cx3cl1, at any time points or in any brain regions investigated. This study suggests that propofol anaesthesia does not have a major impact on pro-inflammatory cytokine expression profiles in the developing central nervous system during the brain growth spurt. These results raise arguments against the involvement of neuroinflammatory pathways in propofol-related neurotoxicity observed following the administration of this drug in the early postnatal period.

Developmental remodeling of corticocortical feedback circuits in ferret visual cortex

PubMed Central

Khalil, Reem; Levitt, Jonathan B.

2014-01-01

Visual cortical areas in the mammalian brain are linked through a system of interareal feedforward and feedback connections, which presumably underlie different visual functions. We characterized the refinement of feedback projections to primary visual cortex (V1) from multiple sources in juvenile ferrets ranging in age from four to ten weeks postnatal. We studied whether the refinement of different aspects of feedback circuitry from multiple visual cortical areas proceeds at a similar rate in all areas. We injected the neuronal tracer cholera toxin B (CTb) into V1, and mapped the areal and laminar distribution of retrogradely labeled cells in extrastriate cortex. Around the time of eye opening at four weeks postnatal, the retinotopic arrangement of feedback appears essentially adultlike; however, Suprasylvian cortex supplies the greatest proportion of feedback, whereas area 18 supplies the greatest proportion in the adult. The density of feedback cells and the ratio of supragranular/infragranular feedback contribution declined in this period at a similar rate in all cortical areas. We also find significant feedback to V1 from layer IV of all extrastriate areas. The regularity of cell spacing, the proportion of feedback arising from layer IV, and the tangential extent of feedback in each area all remained essentially unchanged during this period, except for the infragranular feedback source in area 18 which expanded. Thus, while much of the basic pattern of cortical feedback to V1 is present before eye opening, there is major synchronous reorganization after eye opening, suggesting a crucial role for visual experience in this remodeling process. PMID:24665018

Developmental remodeling of corticocortical feedback circuits in ferret visual cortex.

PubMed

Khalil, Reem; Levitt, Jonathan B

2014-10-01

Visual cortical areas in the mammalian brain are linked through a system of interareal feedforward and feedback connections, which presumably underlie different visual functions. We characterized the refinement of feedback projections to primary visual cortex (V1) from multiple sources in juvenile ferrets ranging in age from 4-10 weeks postnatal. We studied whether the refinement of different aspects of feedback circuitry from multiple visual cortical areas proceeds at a similar rate in all areas. We injected the neuronal tracer cholera toxin B (CTb) into V1 and mapped the areal and laminar distribution of retrogradely labeled cells in extrastriate cortex. Around the time of eye opening at 4 weeks postnatal, the retinotopic arrangement of feedback appears essentially adult-like; however, suprasylvian cortex supplies the greatest proportion of feedback, whereas area 18 supplies the greatest proportion in the adult. The density of feedback cells and the ratio of supragranular/infragranular feedback contribution declined in this period at a similar rate in all cortical areas. We also found significant feedback to V1 from layer IV of all extrastriate areas. The regularity of cell spacing, the proportion of feedback arising from layer IV, and the tangential extent of feedback in each area all remained essentially unchanged during this period, except for the infragranular feedback source in area 18, which expanded. Thus, while much of the basic pattern of cortical feedback to V1 is present before eye opening, there is major synchronous reorganization after eye opening, suggesting a crucial role for visual experience in this remodeling process. © 2014 Wiley Periodicals, Inc.

Glutamatergic and GABAergic neurotransmitter cycling and energy metabolism in rat cerebral cortex during postnatal development.

PubMed

Chowdhury, Golam M I; Patel, Anant B; Mason, Graeme F; Rothman, Douglas L; Behar, Kevin L

2007-12-01

The contribution of glutamatergic and gamma-aminobutyric acid (GABA)ergic neurons to oxidative energy metabolism and neurotransmission in the developing brain is not known. Glutamatergic and GABAergic fluxes were assessed in neocortex of postnatal day 10 (P10) and 30 (P30) urethane-anesthetized rats infused intravenously with [1,6-(13)C(2)]glucose for different time intervals (time course) or with [2-(13)C]acetate for 2 to 3 h (steady state). Amino acid levels and (13)C enrichments were determined in tissue extracts ex vivo using (1)H-[(13)C]-NMR spectroscopy. Metabolic fluxes were estimated from the best fits of a three-compartment metabolic model (glutamatergic neurons, GABAergic neurons, and astroglia) to the (13)C-enrichment time courses of amino acids from [1,6-(13)C(2)]glucose, constrained by the ratios of neurotransmitter cycling (V(cyc))-to-tricarboxylic acid (TCA) cycle flux (V(TCAn)) calculated from the steady-state [2-(13)C]acetate enrichment data. From P10 to P30 increases in total neuronal (glutamate plus GABA) TCA cycle flux (3 x ; 0.24+/-0.05 versus 0.71+/-0.07 micromol per g per min, P<0.0001) and total neurotransmitter cycling flux (3.1 to 5 x ; 0.07 to 0.11 (+/-0.03) versus 0.34+/-0.03 micromol per g per min, P<0.0001) were approximately proportional. Incremental changes in total cycling (DeltaV(cyc(tot))) and neuronal TCA cycle flux (DeltaV(TCAn(tot))) between P10 and P30 were 0.23 to 0.27 and 0.47 micromol per g per min, respectively, similar to the approximately 1:2 relationship previously reported for adult cortex. For the individual neurons, increases in V(TCAn) and V(cyc) were similar in magnitude (glutamatergic neurons, 2.7 x versus 2.8 to 4.6 x ; GABAergic neurons, approximately 5 x versus approximately 7 x), although GABAergic flux changes were larger. The findings show that glutamate and GABA neurons undergo large and approximately proportional increases in neurotransmitter cycling and oxidative energy metabolism during this major postnatal growth spurt.

Expression of the System N transporter (SNAT5/SN2) during development indicates its plausible role in glutamatergic neurotransmission.

PubMed

Rodríguez, Angelina; Ortega, Arturo; Berumen, Laura C; García-Alcocer, María G; Giménez, Cecilio; Zafra, Francisco

2014-07-01

Solute neutral amino acid transporter 5 (SNAT5/SN2) is a member of the System N family, expressed in glial cells in the adult brain, able to transport glutamine, histidine or glycine among other substrates. Its tight association with synapses and its electroneutral mode of operation that allows the bidirectional movement of substrates, supports the idea that this transporter participates in the function of the glutamine-glutamate cycle between neurons and glia. Moreover, SNAT5/SN2 might contribute to the regulation of glycine concentration in glutamatergic synapses and, therefore, to the functioning of the N-methyl-d-aspartate (NMDA) subtype of glutamate receptors. Ontogenic maturation of these synapses occurs postnatally through the coordinate expression of a large number of receptors, transporters, structural and regulatory proteins that ensure the correct operation of the excitatory pathways in the central nervous system. Since the temporal pattern of expression of SNAT5/SN2 is unknown, we analyzed it by immunoblot and immunohistochemical techniques. Results indicate that the expression of SNAT5/SN2 is triggered between the second and third postnatal week in the cerebral cortex, in parallel to the expression of the vesicular glutamate transporter vGLUT1 and the glial glutamate transporter GLT1/EAAT2. In the cerebellum, this process occurs about one week later than in the cerebral cortex. Immunohistochemical staining of cortical sections shows that from postnatal day 14 to adulthood the transporter was expressed exclusively in glial cells. Our results are consistent with the idea that SNAT5/SN2 expression is coordinated with that of other proteins necessary for the operation of glutamatergic synapses and reinforce the existence of a regulatory cross-talk between neurons and glia that orchestrates the building up of these synapses. Copyright © 2014 Elsevier Ltd. All rights reserved.

The abrupt development of adult-like grid cell firing in the medial entorhinal cortex

PubMed Central

Wills, Thomas J.; Barry, Caswell; Cacucci, Francesca

2012-01-01

Understanding the development of the neural circuits subserving specific cognitive functions such as navigation remains a central problem in neuroscience. Here, we characterize the development of grid cells in the medial entorhinal cortex, which, by nature of their regularly spaced firing fields, are thought to provide a distance metric to the hippocampal neural representation of space. Grid cells emerge at the time of weaning in the rat, at around 3 weeks of age. We investigated whether grid cells in young rats are functionally equivalent to those observed in the adult as soon as they appear, or if instead they follow a gradual developmental trajectory. We find that, from the very youngest ages at which reproducible grid firing is observed (postnatal day 19): grid cells display adult-like firing fields that tessellate to form a coherent map of the local environment; that this map is universal, maintaining its internal structure across different environments; and that grid cells in young rats, as in adults, also encode a representation of direction and speed. To further investigate the developmental processes leading up to the appearance of grid cells, we present data from individual medial entorhinal cortex cells recorded across more than 1 day, spanning the period before and after the grid firing pattern emerged. We find that increasing spatial stability of firing was correlated with increasing gridness. PMID:22557949

Deficits in adult prefrontal cortex neurons and behavior following early post-natal NMDA antagonist treatment.

PubMed

Coleman, Leon G; Jarskog, L Fredrik; Moy, Sheryl S; Crews, Fulton T

2009-09-01

The prefrontal cortex (PFC) is associated with higher cognitive functions including attention and working memory and has been implicated in the regulation of impulsivity as well as the pathology of complex mental illnesses. N-methyl D-aspartate (NMDA) antagonist treatment with dizocilpine induces cell death which is greatest in the frontal cortex on post-natal day seven (P7), however the long-term structural and behavioral effects of this treatment are unknown. This study investigates both the acute neurotoxicity of P7 dizocilpine and the persistent effects of this treatment on pyramidal cells and parvalbumin interneurons in the adult PFC, a brain region involved in the regulation of impulsivity. Dizocilpine treatment on P7 increased cleaved caspase-3 immunoreactivity (IR) in the PFC on P8. In adult mice (P82), P7 dizocilpine treatment resulted in 50% fewer parvalbumin-positive interneurons (p<0.01) and 42% fewer layer V pyramidal neurons (p<0.01) in the PFC. Double immunohistochemistry revealed cleaved caspase-3 IR in both GAD67 IR interneurons and GAD67 (-) neurons. Following dizocilpine treatment at P7, adults showed reduced time in the center of the open field suggesting increased anxiety-like behavior. These findings indicate that early brain insults affecting glutamatergic neurotransmission lead to persistent brain pathology that could contribute to impulsivity and cognitive dysfunction.

Environmental Enrichment Alters Neurotrophin Levels After Fetal Alcohol Exposure in Rats

PubMed Central

Parks, Elizabeth A.; McMechan, Andrew P.; Hannigan, John H.; Berman, Robert F.

2014-01-01

Background Prenatal alcohol exposure causes abnormal brain development, leading to behavioral deficits, some of which can be ameliorated by environmental enrichment. As both environmental enrichment and prenatal alcohol exposure can individually alter neurotrophin expression, we studied the interaction of prenatal alcohol and postweaning environmental enrichment on brain neurotrophin levels in rats. Methods Pregnant rats received alcohol by gavage, 0, 4, or 6 g / kg / d (Zero, Low, or High groups), or no treatment (Naïve group), on gestational days 8 to 20. After weaning on postnatal day 21, offspring were housed for 6 weeks in Isolated, Social, or Enriched conditions. Levels of nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), and neurotrophin-3 (NT-3) were then measured in frontal cortex, occipital cortex, hippocampus, and cerebellar vermis. Results Prenatal alcohol exposure increased NGF levels in frontal cortex (High-dose group) and cerebellar vermis (High- and Low-dose groups); increased BDNF in frontal cortex, occipital cortex and hippocampus (Low-dose groups), and increased NT-3 in hippocampus and cerebellar vermis (High-dose). Environmental enrichment resulted in lower NGF, BDNF, and NT-3 levels in occipital cortex and lower NGF in frontal cortex. The only significant interaction between prenatal alcohol treatment and environment was in cerebellar vermis where NT-3 levels were higher for enriched animals after prenatal alcohol exposure, but not for animals housed under Isolated or Social conditions. Conclusions Both prenatal alcohol exposure and postweaning housing conditions alter brain neurotrophin levels, but the effects appear to be largely independent. Although environmental enrichment can improve functional outcomes, these results do not provide strong support for the hypothesis that rearing in a complex environment ameliorates prenatal alcohol effects on brain neurotrophin levels in rats. PMID:18652597

Angiotensin II-AT1-receptor signaling is necessary for cyclooxygenase-2-dependent postnatal nephron generation.

PubMed

Frölich, Stefanie; Slattery, Patrick; Thomas, Dominique; Goren, Itamar; Ferreiros, Nerea; Jensen, Boye L; Nüsing, Rolf M

2017-04-01

Deletion of cyclooxygenase-2 (COX-2) causes impairment of postnatal kidney development. Here we tested whether the renin angiotensin system contributes to COX-2-dependent nephrogenesis in mice after birth and whether a rescue of impaired renal development and function in COX-2 -/- mice was achievable. Plasma renin concentration in mouse pups showed a birth peak and a second peak around day P8 during the first 10 days post birth. Administration of the angiotensin II receptor AT1 antagonist telmisartan from day P1 to P3 did not result in cortical damage. However, telmisartan treatment from day P3 to P8, the critical time frame of renal COX-2 expression, led to hypoplastic glomeruli, a thinned subcapsular cortex and maturational arrest of superficial glomeruli quite similar to that observed in COX-2 -/- mice. In contrast, AT2 receptor antagonist PD123319 was without any effect on renal development. Inhibition of the renin angiotensin system by aliskiren and enalapril caused similar glomerular defects as telmisartan. Administration of the AT1 receptor agonist L162313 to COX-2 -/- pups improved kidney growth, ameliorated renal defects, but had no beneficial effect on reduced cortical mass. L162313 rescued impaired renal function by reducing serum urea and creatinine and mitigated pathologic albumin excretion. Moreover, glomerulosclerosis in the kidneys of COX-2 -/- mice was reduced. Thus, angiotensin II-AT1-receptor signaling is necessary for COX-2-dependent normal postnatal nephrogenesis and maturation. Copyright © 2016 International Society of Nephrology. Published by Elsevier Inc. All rights reserved.

A Subtype-Specific Critical Period for Neurogenesis in the Postnatal Development of Mouse Olfactory Glomeruli

PubMed Central

Ito, Keishi; Arakawa, Sousuke; Murakami, Shingo; Sawamoto, Kazunobu

2012-01-01

Sensory input is essential for the normal development of sensory centers in the brain, such as the somatosensory, visual, auditory, and olfactory systems. Visual deprivation during a specific developmental stage, called the critical period, results in severe and irreversible functional impairments in the primary visual cortex. Olfactory deprivation in the early postnatal period also causes significant developmental defects in the olfactory bulb, the primary center for olfaction. Olfactory bulb interneurons are continuously generated from neural stem cells in the ventricular-subventricular zone, suggesting that the olfactory system has plasticity even in adulthood. Here, we investigated the effect of transient neonatal olfactory deprivation on the addition of interneurons to the glomerular layer of the adult mouse olfactory bulb. We found that the addition of one subtype of interneurons was persistently inhibited even after reopening the naris. BrdU pulse-chase experiments revealed that the neonatal olfactory deprivation predominantly affected an early phase in the maturation of this neuronal subtype in the olfactory bulb. Subjecting the mice to odor stimulation for 6 weeks after naris reopening resulted in significant recovery from the histological and functional defects caused by the olfactory deprivation. These results suggest that a subtype-specific critical period exists for olfactory bulb neurogenesis, but that this period is less strict and more plastic compared with the critical periods for other systems. This study provides new insights into the mechanisms of postnatal neurogenesis and a biological basis for the therapeutic effect of olfactory training. PMID:23133633

Experimental intrauterine growth retardation.

PubMed

van Marthens, E; Harel, S; Zamenshof, S

1975-01-01

The effects of experimental intrauterine growth retardation on subsequent fetal development, especially with respect to brain development, were studied in a new animal model. The rabbit was chosen since it has a perinatal pattern of brain development similar to that of the human. Experimental ischemia was induced during the last trimester by ligation of spiral arterioles and the differential effects on fetal development at term (30th gestational day) are reported. Specific brain regions were examined for wet weight, total cell number (DNA) and total protein content. Highly significant decreases in all these parameters were found in both the cortex and cerebellum following experimental intrauterine growth retardation; these two organs were differentially affected. The prospects and advantages of using this animal model for the study of the postnatal "catch-up growth" are discussed.

Rapid Postnatal Expansion of Neural Networks Occurs in an Environment of Altered Neurovascular and Neurometabolic Coupling.

PubMed

Kozberg, Mariel G; Ma, Ying; Shaik, Mohammed A; Kim, Sharon H; Hillman, Elizabeth M C

2016-06-22

In the adult brain, increases in neural activity lead to increases in local blood flow. However, many prior measurements of functional hemodynamics in the neonatal brain, including functional magnetic resonance imaging (fMRI) in human infants, have noted altered and even inverted hemodynamic responses to stimuli. Here, we demonstrate that localized neural activity in early postnatal mice does not evoke blood flow increases as in the adult brain, and elucidate the neural and metabolic correlates of these altered functional hemodynamics as a function of developmental age. Using wide-field GCaMP imaging, the development of neural responses to somatosensory stimulus is visualized over the entire bilaterally exposed cortex. Neural responses are observed to progress from tightly localized, unilateral maps to bilateral responses as interhemispheric connectivity becomes established. Simultaneous hemodynamic imaging confirms that spatiotemporally coupled functional hyperemia is not present during these early stages of postnatal brain development, and develops gradually as cortical connectivity is established. Exploring the consequences of this lack of functional hyperemia, measurements of oxidative metabolism via flavoprotein fluorescence suggest that neural activity depletes local oxygen to below baseline levels at early developmental stages. Analysis of hemoglobin oxygenation dynamics at the same age confirms oxygen depletion for both stimulus-evoked and resting-state neural activity. This state of unmet metabolic demand during neural network development poses new questions about the mechanisms of neurovascular development and its role in both normal and abnormal brain development. These results also provide important insights for the interpretation of fMRI studies of the developing brain. This work demonstrates that the postnatal development of neuronal connectivity is accompanied by development of the mechanisms that regulate local blood flow in response to neural activity. Novel in vivo imaging reveals that, in the developing mouse brain, strong and localized GCaMP neural responses to stimulus fail to evoke local blood flow increases, leading to a state in which oxygen levels become locally depleted. These results demonstrate that the development of cortical connectivity occurs in an environment of altered energy availability that itself may play a role in shaping normal brain development. These findings have important implications for understanding the pathophysiology of abnormal developmental trajectories, and for the interpretation of functional magnetic resonance imaging data acquired in the developing brain. Copyright © 2016 the authors 0270-6474/16/366704-14$15.00/0.

Chronic postnatal stress induces voluntary alcohol intake and modifies glutamate transporters in adolescent rats.

PubMed

Odeon, María Mercedes; Andreu, Marcela; Yamauchi, Laura; Grosman, Mauricio; Acosta, Gabriela Beatriz

2015-01-01

Postnatal stress alters stress responses for life, with serious consequences on the central nervous system (CNS), involving glutamatergic neurotransmission and development of voluntary alcohol intake. Several drugs of abuse, including alcohol and cocaine, alter glutamate transport (GluT). Here, we evaluated effects of chronic postnatal stress (CPS) on alcohol intake and brain glutamate uptake and transporters in male adolescent Wistar rats. For CPS from postnatal day (PD) 7, pups were separated from their mothers and exposed to cold stress (4 °C) for 1 h daily for 20 days; controls remained with their mothers. Then they were exposed to either voluntary ethanol (6%) or dextrose (1%) intake for 7 days (5-7 rats per group), then killed. CPS: (1) increased voluntary ethanol intake, (2) did not affect body weight gain or produce signs of toxicity with alcohol exposure, (3) increased glutamate uptake by hippocampal synaptosomes in vitro and (4) reduced protein levels (Western measurements) in hippocampus and frontal cortex of glial glutamate transporter-1 (GLT-1) and excitatory amino-acid transporter-3 (EAAT-3) but increased glutamate aspartate transporter (GLAST) levels. We propose that CPS-induced decrements in GLT-1 and EAAT-3 expression levels are opposed by activation of a compensatory mechanism to prevent excitotoxicity. A greater role for GLAST in total glutamate uptake to prevent enlarged extracellular glutamate levels is inferred. Although CPS strongly increased intake of ethanol, this had little impact on effects of CPS on brain glutamate uptake or transporters. However, the impact of early life adverse events on glutamatergic neurotransmission may underlie increased alcohol consumption in adulthood.

Differential cadherin expression in the developing postnatal telencephalon of a New World monkey.

PubMed

Matsunaga, Eiji; Nambu, Sanae; Oka, Mariko; Iriki, Atsushi

2013-12-01

Cadherins are cell adhesion molecules widely expressed in the nervous system, where they play various roles in neural patterning, nuclei formation, axon guidance, and synapse formation and function. Although many published articles have reported on cadherin expression in rodents and ferrets, there are limited data on their expression in primate brains. In this study, in situ hybridization analysis was performed for 10 cadherins [nine classic cadherins (Cdh4, -6, -7, -8, -9, -10, -11, -12, and -20) and T-cadherin (Cdh13)] in the developing postnatal telencephalon of the common marmoset (Callithrix jacchus). Each cadherin showed broad expression in the cerebral cortex, basal ganglia, amygdala, and hippocampus, as previously shown in the rodent brain. However, detailed expression patterns differed between rodents and marmosets. In contrast to rodents, cadherin expression was reduced overall and localized to restricted areas of the brain during the developmental process, suggesting that cadherins are more crucially involved in developmental or maturation processes rather than in neural functioning. These results also highlight the possibility that restricted/less redundant cadherin expression allows primate brains to generate functional diversity among neurons, allowing morphological and functional differences between rodents and primates. Copyright © 2013 Wiley Periodicals, Inc.

Schizophrenia Risk Variation in the NRG1 gene Exerts Effects on NRG1-IV Splicing During Fetal and Early Postnatal Human Neocortical Development

PubMed Central

Paterson, Clare; Wang, Yanhong; Kleinman, Joel E.; Law, Amanda J.

2015-01-01

OBJECTIVE Neuregulin 1 (NRG1) is a multifunctional neurotrophin and a critical mediator of neurodevelopment and risk for schizophrenia. NRG1 undergoes extensive alternative splicing, and association of brain NRG1-IV isoform expression with the schizophrenia-risk polymorphism, rs6994992, is a potential molecular mechanism of risk. Novel splice variants of NRG1-IV (NRG1-IVNV), with predicted unique signaling capabilities, have been cloned in fetal brain. Because the developmental expression and genetic regulation of NRG1-IVNV in human brain and relationship to schizophrenia is unknown, the authors investigated the temporal dynamics of NRG1-IVNV transcription, compared to the major NRG1 isoforms (types I-IV), across human prenatal and postnatal prefrontal cortical development and examined the association of rs6994992 with NRG1-IVNV expression. METHOD NRG1, types I-IV and NRG1-IVNV isoform expression was evaluated using quantitative real-time PCR in prefrontal cortex during human fetal brain development (14-39 weeks gestation: N=41) and postnatally through aging (age range 0-83 years: N=195). The association of rs6994992 genotype with NRG1-IVNV expression was determined. In-vitro assays were performed to determine the subcellular distribution and proteolytic processing of NRG1-IVNV isoforms. RESULTS Expression of NRG1, types I, II, III was temporally regulated during human prenatal and postnatal neocortical development and the trajectory of NRG1-IVNV was unique, being expressed from 16 weeks gestation until 3 years of age, after which it was undetectable. NRG1-IVNVs expression was associated with rs6994992 genotype, whereby homozygosity for the schizophrenia-risk allele (T) conferred lower cortical NRG1-IVNV levels. Finally, in-vitro cellular assays demonstrate that NRG1-IVNV is a novel nuclear enriched, truncated NRG1 protein that is resistant to proteolytic processing. CONCLUSION This study provides the first quantitative map of NRG1 isoform expression during human neocortical development and aging and identifies a potential mechanism of early developmental risk for schizophrenia at the NRG1 locus, involving a novel class of NRG1 proteins. PMID:24935406

Prenatal ketamine exposure causes abnormal development of prefrontal cortex in rat

PubMed Central

Zhao, Tianyun; Li, Chuanxiang; Wei, Wei; Zhang, Haixing; Ma, Daqing; Song, Xingrong; Zhou, Libing

2016-01-01

Ketamine is commonly used for anesthesia and as a recreational drug. In pregnant users, a potential neurotoxicity in offspring has been noted. Our previous work demonstrated that ketamine exposure of pregnant rats induces affective disorders and cognitive impairments in offspring. As the prefrontal cortex (PFC) is critically involved in emotional and cognitive processes, here we studied whether maternal ketamine exposure influences the development of the PFC in offspring. Pregnant rats on gestational day 14 were treated with ketamine at a sedative dose for 2 hrs, and pups were studied at postnatal day 0 (P0) or P30. We found that maternal ketamine exposure resulted in cell apoptosis and neuronal loss in fetal brain. Upon ketamine exposure in utero, PFC neurons at P30 showed more dendritic branching, while cultured neurons from P0 PFC extended shorter neurites than controls. In addition, maternal ketamine exposure postponed the switch of NR2B/2A expression, and perturbed pre- and postsynaptic protein expression in the PFC. These data suggest that prenatal ketamine exposure impairs neuronal development of the PFC, which may be associated with abnormal behavior in offsprings. PMID:27226073

Early-life exposure to caffeine affects the construction and activity of cortical networks in mice.

PubMed

Fazeli, Walid; Zappettini, Stefania; Marguet, Stephan Lawrence; Grendel, Jasper; Esclapez, Monique; Bernard, Christophe; Isbrandt, Dirk

2017-09-01

The consumption of psychoactive drugs during pregnancy can have deleterious effects on newborns. It remains unclear whether early-life exposure to caffeine, the most widely consumed psychoactive substance, alters brain development. We hypothesized that maternal caffeine ingestion during pregnancy and the early postnatal period in mice affects the construction and activity of cortical networks in offspring. To test this hypothesis, we focused on primary visual cortex (V1) as a model neocortical region. In a study design mimicking the daily consumption of approximately three cups of coffee during pregnancy in humans, caffeine was added to the drinking water of female mice and their offspring were compared to control offspring. Caffeine altered the construction of GABAergic neuronal networks in V1, as reflected by a reduced number of somatostatin-containing GABA neurons at postnatal days 6-7, with the remaining ones showing poorly developed dendritic arbors. These findings were accompanied by increased synaptic activity in vitro and elevated network activity in vivo in V1. Similarly, in vivo hippocampal network activity was altered from the neonatal period until adulthood. Finally, caffeine-exposed offspring showed increased seizure susceptibility in a hyperthermia-induced seizure model. In summary, our results indicate detrimental effects of developmental caffeine exposure on mouse brain development. Copyright © 2017 Elsevier Inc. All rights reserved.

Glucocorticoids are critical regulators of dendritic spine development and plasticity in vivo

PubMed Central

Liston, Conor; Gan, Wen-Biao

2011-01-01

Glucocorticoids are a family of hormones that coordinate diverse physiological processes in responding to stress. Prolonged glucocorticoid exposure over weeks has been linked to dendritic atrophy and spine loss in fixed tissue studies of adult brains, but it is unclear how glucocorticoids may affect the dynamic processes of dendritic spine formation and elimination in vivo. Furthermore, relatively few studies have examined the effects of stress and glucocorticoids on spines during the postnatal and adolescent period, which is characterized by rapid synaptogenesis followed by protracted synaptic pruning. To determine whether and to what extent glucocorticoids regulate dendritic spine development and plasticity, we used transcranial two-photon microscopy to track the formation and elimination of dendritic spines in vivo after treatment with glucocorticoids in developing and adult mice. Corticosterone, the principal murine glucocorticoid, had potent dose-dependent effects on dendritic spine dynamics, increasing spine turnover within several hours in the developing barrel cortex. The adult barrel cortex exhibited diminished baseline spine turnover rates, but these rates were also enhanced by corticosterone. Similar changes occurred in multiple cortical areas, suggesting a generalized effect. However, reducing endogenous glucocorticoid activity by dexamethasone suppression or corticosteroid receptor antagonists caused a substantial reduction in spine turnover rates, and the former was reversed by corticosterone replacement. Notably, we found that chronic glucocorticoid excess led to an abnormal loss of stable spines that were established early in life. Together, these findings establish a critical role for glucocorticoids in the development and maintenance of dendritic spines in the living cortex. PMID:21911374

A Mouse Model for Conditional Secretion of Specific Single-Chain Antibodies Provides Genetic Evidence for Regulation of Cortical Plasticity by a Non-cell Autonomous Homeoprotein Transcription Factor.

PubMed

Bernard, Clémence; Vincent, Clémentine; Testa, Damien; Bertini, Eva; Ribot, Jérôme; Di Nardo, Ariel A; Volovitch, Michel; Prochiantz, Alain

2016-05-01

During postnatal life the cerebral cortex passes through critical periods of plasticity allowing its physiological adaptation to the environment. In the visual cortex, critical period onset and closure are influenced by the non-cell autonomous activity of the Otx2 homeoprotein transcription factor, which regulates the maturation of parvalbumin-expressing inhibitory interneurons (PV cells). In adult mice, the maintenance of a non-plastic adult state requires continuous Otx2 import by PV cells. An important source of extra-cortical Otx2 is the choroid plexus, which secretes Otx2 into the cerebrospinal fluid. Otx2 secretion and internalization requires two small peptidic domains that are part of the DNA-binding domain. Thus, mutating these "transfer" sequences also modifies cell autonomous transcription, precluding this approach to obtain a cell autonomous-only mouse. Here, we develop a mouse model with inducible secretion of an anti-Otx2 single-chain antibody to trap Otx2 in the extracellular milieu. Postnatal secretion of this single-chain antibody by PV cells delays PV maturation and reduces plasticity gene expression. Induced adult expression of this single-chain antibody in cerebrospinal fluid decreases Otx2 internalization by PV cells, strongly induces plasticity gene expression and reopens physiological plasticity. We provide the first mammalian genetic evidence for a signaling mechanism involving intercellular transfer of a homeoprotein transcription factor. Our single-chain antibody mouse model is a valid strategy for extracellular neutralization that could be applied to other homeoproteins and signaling molecules within and beyond the nervous system.

Cellular and laminar expression of Dab-1 during the postnatal critical period in cat visual cortex and the effects of dark rearing.

PubMed

Kiser, Paul J; Liu, Zijing; Wilt, Steven D; Mower, George D

2011-04-06

This study describes postnatal critical period changes in cellular and laminar expression of Dab-1, a gene shown to play a role in controlling neuronal positioning during embryonic brain development, in cat visual cortex and the effects of dark rearing (DR). At 1week, there is dense cellular staining which is uniform across cortical layers and very light neuropil staining. At the peak of the critical period (5weeks), dense cell staining is largely restricted to large pyramidal cells of deep layer III and layer V, there is faint cell body staining throughout all cortical layers, neuropil staining is markedly increased and uniform in layers III to VI. This dramatic change in laminar and cellular labeling is independent of visual input, since immunostaining is similar in 5-week DR cats. By 10weeks, the mature laminar and cellular staining pattern is established and the major subsequent change is a further reduction in the density of cellular staining in all cortical layers. Neuropil staining is pronounced and uniform across cortical layers. These developmental changes are altered by DR. Quantification by cell counts indicated that age and DR interact such that differences in cellular expression are opposite in direction between 5- and 20-week-old cats. This bidirectional regulation of cellular expression is the same in all cortical laminae. The bidirectional regulation of cellular expression matches the effects of age and DR on physiological plasticity during the critical period as assessed by ocular dominance shifts in response to monocular deprivation. Copyright © 2011 Elsevier B.V. All rights reserved.

Tunicamycin-induced unfolded protein response in the developing mouse brain

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Haiping; Wang, Xin; Ke, Zun-Ji

Accumulation of unfolded or misfolded proteins in the endoplasmic reticulum (ER) causes ER stress, resulting in the activation of the unfolded protein response (UPR). ER stress and UPR are associated with many neurodevelopmental and neurodegenerative disorders. The developing brain is particularly susceptible to environmental insults which may cause ER stress. We evaluated the UPR in the brain of postnatal mice. Tunicamycin, a commonly used ER stress inducer, was administered subcutaneously to mice of postnatal days (PDs) 4, 12 and 25. Tunicamycin caused UPR in the cerebral cortex, hippocampus and cerebellum of mice of PD4 and PD12, which was evident bymore » the upregulation of ATF6, XBP1s, p-eIF2α, GRP78, GRP94 and MANF, but failed to induce UPR in the brain of PD25 mice. Tunicamycin-induced UPR in the liver was observed at all stages. In PD4 mice, tunicamycin-induced caspase-3 activation was observed in layer II of the parietal and optical cortex, CA1–CA3 and the subiculum of the hippocampus, the cerebellar external germinal layer and the superior/inferior colliculus. Tunicamycin-induced caspase-3 activation was also shown on PD12 but to a much lesser degree and mainly located in the dentate gyrus of the hippocampus, deep cerebellar nuclei and pons. Tunicamycin did not activate caspase-3 in the brain of PD25 mice and the liver of all stages. Similarly, immature cerebellar neurons were sensitive to tunicamycin-induced cell death in culture, but became resistant as they matured in vitro. These results suggest that the UPR is developmentally regulated and the immature brain is more susceptible to ER stress. - Highlights: • Tunicamycin caused a development-dependent UPR in the mouse brain. • Immature brain was more susceptible to tunicamycin-induced endoplasmic reticulum stress. • Tunicamycin caused more neuronal death in immature brain than mature brain. • Tunicamycin-induced neuronal death is region-specific.« less

Structural and ultrastructural evidence of neurotoxic effects of fried potato chips on rat postnatal development.

PubMed

El-Sayyad, Hassan I; El-Gammal, Hekmat L; Habak, Lotfy A; Abdel-Galil, Heba M; Fernando, Augusta; Gaur, Rajiv L; Ouhtit, Allal

2011-10-01

Acrylamide (ACR), a proved rodent carcinogen and neurotoxic agent, is present in significant quantities in commonly consumed foods such as fried potato chips (FPC) and French fries, raising a health concern worldwide. We investigated and compared the neurotoxic effects of ACR and FPC on postnatal development. Female rats were treated with ACR (30 mg/kg of body weight), fed a diet containing approximately 30% of FPC during pregnancy, or fed a standard diet (control) and their offspring were examined. Female rats treated with ACR or fed a diet containing FPC during pregnancy gave birth to litters with delayed growth and decreased body and brain weights. Light microscopic studies of the cerebellar cortex of treated animals revealed drastic decreases in Purkinje cells and internal granular layers. Different patterns of cell death were detected in Purkinje cells and neurons in the brains of pups born to treated mothers. Ultrastructural analysis of Purkinje cells revealed changes in the endoplasmic reticulum, loss of the normal arrangement of polyribosomes, swollen mitochondria with abnormally differentiated cristae, and an abnormal Golgi apparatus. The gastrocnemius muscle in the ACR and FPC groups showed extensive degeneration of myofibrils as evidenced by poorly differentiated A, H, and Z bands. The present study reveals for the first time that rat fetal exposure to ACR, as a pure compound or from a maternal diet of FPC, causes cerebellar cortical defects and myodegeneration of the gastrocnemius muscle during the postnatal development of pups. These results warrant a systematic study of the health effects of the consumption of FPC and French fries in the general population. Copyright © 2011. Published by Elsevier Inc.

Neonatal Stress Has a Long-Lasting Sex-Dependent Effect on Anxiety-Like Behavior and Neuronal Morphology in the Prefrontal Cortex and Hippocampus.

PubMed

de Melo, Silvana Regina; de David Antoniazzi, Caren Tatiane; Hossain, Shakhawat; Kolb, Bryan

2018-01-01

The long-lasting effects of early stress on brain development have been well studied. Recent evidence indicates that males and females respond differently to the same stressor. We examined the chronic effects of daily maternal separation (MS) on behavior and cerebral morphology in both male and female rats. Cognitive and anxiety-like behaviors were evaluated, and neuroplastic changes in 2 subregions of the prefrontal cortex (dorsal agranular insular cortex [AID] and cingulate cortex [Cg3]) and hippocampus (CA1 and dentate gyrus) were measured in adult male and female rats. The animals were subjected to MS on postnatal day (P) 3-14 for 3 h per day. Cognitive and emotional behaviors were assessed in the object/context mismatch task, elevated plus maze, and locomotor activity test in early adulthood (P87-P95). Anatomical assessments were performed in the prefrontal cortex (i.e., cortical thickness and spine density) and hippocampus (i.e., spine density). Sex-dependent effects were observed. MS increased anxiety-related behavior only in males, whereas locomotor activity was higher in females, with no effects on cognition. MS decreased spine density in the AID and increased spine density in the CA1 area in males. Females exhibited an increase in spine density in the Cg3. Our findings confirm previous work that found that MS causes long-term behavioral and anatomical effects, and these effects were dependent on sex and the duration of MS stress. © 2018 S. Karger AG, Basel.

The postnatal 5-HT1A receptor regulates adult anxiety and depression differently via multiple molecules.

PubMed

Ishikawa, Chihiro; Shiga, Takashi

2017-08-01

Serotonin (5-HT) and the 5-HT 1A receptor during development are known to modulate anxiety and depression in later life. However, the brain mechanisms linking the postnatal 5-HT system and adult behavior remain unknown. Here, we examined the effects of pharmacological 5-HT 1A receptor activation during the postnatal period on anxiety and depression-like behavior in adult BALB/c male mice. To elucidate the underlying mechanisms, we measured mRNA expression of the 5-HT 1A receptor, brain-derived neurotrophic factor (BDNF), GABA A receptor subunits, and AMPA receptor subunits in the medial prefrontal cortex (mPFC), amygdala, and hippocampus. Treatment with the selective 5-HT reuptake inhibitor (fluoxetine) and 5-HT 1A receptor agonist (8-OH-DPAT) during the postnatal period decreased anxiety-like behavior in adulthood, whereas only 8-OH-DPAT treatment increased depression-like behavior. Concomitantly with the behavioral effects, postnatal treatment with fluoxetine and 8-OH-DPAT decreased the mRNA expression of the GABA A receptor α3 subunit in the mPFC and ventral hippocampus in adulthood, while 8-OH-DPAT, but not fluoxetine, decreased the mRNA expression of the 5-HT 1A receptor and BDNF in the mPFC and the GABA A receptor α2 subunit in the mPFC and ventral hippocampus. On the basis of the correlative changes between behavior and mRNA expression, these results suggest that the GABA A receptor α3 subunit in the mPFC and ventral hippocampus may regulate anxiety-like behavior. In contrast, depression-like behavior may be regulated by the 5-HT 1A receptor and BDNF in the mPFC and by the GABA A receptor α2 subunit in the mPFC and ventral hippocampus. In summary, activation of the 5-HT 1A receptor during the postnatal period may reduce anxiety levels, but increase depression levels during adulthood via different multiple molecules in the mPFC and ventral hippocampus. Copyright © 2017 Elsevier Inc. All rights reserved.

Classic cadherin expressions balance postnatal neuronal positioning and dendrite dynamics to elaborate the specific cytoarchitecture of the mouse cortical area.

PubMed

Egusa, Saki F; Inoue, Yukiko U; Asami, Junko; Terakawa, Youhei W; Hoshino, Mikio; Inoue, Takayoshi

2016-04-01

A unique feature of the mammalian cerebral cortex is in its tangential parcellation via anatomical and functional differences. However, the cellular and/or molecular machinery involved in cortical arealization remain largely unknown. Here we map expression profiles of classic cadherins in the postnatal mouse barrel field of the primary somatosensory area (S1BF) and generate a novel bacterial artificial chromosome transgenic (BAC-Tg) mouse line selectively illuminating nuclei of cadherin-6 (Cdh6)-expressing layer IV barrel neurons to confirm that tangential cellular assemblage of S1BF is established by postnatal day 5 (P5). When we electroporate the cadherins expressed in both barrel neurons and thalamo-cortical axon (TCA) terminals limited to the postnatal layer IV neurons, S1BF cytoarchitecture is disorganized with excess elongation of dendrites at P7. Upon delivery of dominant negative molecules for all classic cadherins, tangential cellular positioning and biased dendritic arborization of barrel neurons are significantly altered. These results underscore the value of classic cadherin-mediated sorting among neuronal cell bodies, dendrites and TCA terminals in postnatally elaborating the S1BF-specific tangential cytoarchitecture. Additionally, how the "protocortex" machinery affects classic cadherin expression profiles in the process of cortical arealization is examined and discussed. Copyright © 2015 Elsevier Ireland Ltd and the Japan Neuroscience Society. All rights reserved.

Schizophrenia-Like Dopamine Release Abnormalities in a Mouse Model of NMDA Receptor Hypofunction.

PubMed

Nakao, Kazuhito; Jeevakumar, Vivek; Jiang, Sunny Zhihong; Fujita, Yuko; Diaz, Noelia B; Pretell Annan, Carlos A; Eskow Jaunarajs, Karen L; Hashimoto, Kenji; Belforte, Juan E; Nakazawa, Kazu

2018-01-31

Amphetamine-induced augmentation of striatal dopamine and its blunted release in prefrontal cortex (PFC) is a hallmark of schizophrenia pathophysiology. Although N-methyl-D-aspartate receptor (NMDAR) hypofunction is also implicated in schizophrenia, it remains unclear whether NMDAR hypofunction leads to dopamine release abnormalities. We previously demonstrated schizophrenia-like phenotypes in GABAergic neuron-specific NMDAR hypofunctional mutant mice, in which Ppp1r2-Cre dependent deletion of indispensable NMDAR channel subunit Grin1 is induced in corticolimbic GABAergic neurons including parvalbumin (PV)-positive neurons, in postnatal development, but not in adulthood. Here, we report enhanced dopaminomimetic-induced locomotor activity in these mutants, along with bidirectional, site-specific changes in in vivo amphetamine-induced dopamine release: nucleus accumbens (NAc) dopamine release was enhanced by amphetamine in postnatal Ppp1r2-Cre/Grin1 knockout (KO) mice, whereas dopamine release was dramatically reduced in the medial PFC (mPFC) compared to controls. Basal tissue dopamine levels in both the NAc and mPFC were unaffected. Interestingly, the magnitude and distribution of amphetamine-induced c-Fos expression in dopamine neurons was comparable between genotypes across dopaminergic input subregions in the ventral tegmental area (VTA). These effects appear to be both developmentally and cell-type specifically modulated, since PV-specific Grin1 KO mice could induce the same effects as seen in postnatal-onset Ppp1r2-Cre/Grin1 KO mice, but no such abnormalities were observed in somatostatin-Cre/Grin1 KO mice or adult-onset Ppp1r2-Cre/Grin1 KO mice. These results suggest that PV GABAergic neuron-NMDAR hypofunction in postnatal development confers bidirectional NAc hyper- and mPFC hypo-sensitivity to amphetamine-induced dopamine release, similar to that classically observed in schizophrenia pathophysiology. © The Author(s) 2018. Published by Oxford University Press on behalf of the Maryland Psychiatric Research Center.

Maternal Exposure to PM2.5 during Pregnancy Induces Impaired Development of Cerebral Cortex in Mice Offspring.

PubMed

Zhang, Tianliang; Zheng, Xinrui; Wang, Xia; Zhao, Hui; Wang, Tingting; Zhang, Hongxia; Li, Wanwei; Shen, Hua; Yu, Li

2018-01-16

Air pollution is a serious environmental health problem closely related to the occurrence of central nervous system diseases. Exposure to particulate matter with an aerodynamic diameter less than or equal to 2.5 µm (PM 2.5 ) during pregnancy may affect the growth and development of infants. The present study was to investigate the effects of maternal exposure to PM 2.5 during pregnancy on brain development in mice offspring. Pregnant mice were randomly divided into experimental groups of low-, medium-, or high-dosages of PM 2.5 , a mock-treated group which was treated with the same amount of phosphate buffer solution (PBS), and acontrol group which was untreated. The ethology of offspring mice on postnatal days 1, 7, 14, 21, and 30, along with neuronal development and apoptosis in the cerebral cortex were investigated. Compared with the control, neuronal mitochondrial cristae fracture, changed autophagy characteristics, significantly increased terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) positive cell rate, and mRNA levels of apoptosis-related caspase-8 and caspase-9 were found in cerebral cortex of mice offspring from the treatment groups, with mRNA levels of Bcl-2 and ratio of Bcl-2 to Bax decreased. Treatment groups also demonstrated enhanced protein expressions of apoptosis-related cleaved caspase-3, cleaved caspase-8 and cleaved caspase-9, along with declined proliferating cell nuclear antigen (PCNA), Bcl-2, and ratio of Bcl-2 to Bax. Open field experiments and tail suspension experiments showed that exposure to high dosage of PM 2.5 resulted in decreased spontaneous activities but increased static accumulation time in mice offspring, indicating anxiety, depression, and social behavioral changes. Our results suggested that maternal exposure to PM 2.5 during pregnancy might interfere with cerebral cortex development in mice offspring by affecting cell apoptosis.

Factors influencing frontal cortex development and recovery from early frontal injury.

PubMed

Halliwell, Celeste; Comeau, Wendy; Gibb, Robbin; Frost, Douglas O; Kolb, Bryan

2009-01-01

Neocortical development represents more than a simple unfolding of a genetic blueprint but rather represents a complex dance of genetic and environmental events that interact to adapt the brain to fit a particular environmental context. Although most cortical regions are sensitive to a wide range of experiential factors during development and later in life, the prefrontal cortex appears to be unusually sensitive to perinatal experiences and relatively immune to many adulthood experiences relative to other neocortical regions. One way to examine experience-dependent prefrontal development is to conduct studies in which experiential perturbations are related neuronal morphology. This review of the research reveals both pre- and post-natal factors have important effects on prefrontal development and behaviour. Such factors include psychoactive drugs, including both illicit drugs and prescription drugs, stress, gonadal hormones and sensory and motor stimulation. A second method of study is to examine both the effects of perinatal prefrontal injury on the development of the remaining cerebral mantle and correlated behaviours as well as the effects of post-injury rehabilitation programmes on the anatomical and behavioural measures. Prefrontal injury alters cerebral development in a developmental-stage dependent manner with perinatal injuries having far more deleterious effects than similar injuries later in infancy. The outcome of perinatal injuries can be modified, however, by rehabilitation with many of the factors shown to influence prefrontal development in the otherwise normal brain.

Choline supplementation and DNA methylation in the hippocampus and prefrontal cortex of rats exposed to alcohol during development.

PubMed

Otero, Nicha K H; Thomas, Jennifer D; Saski, Christopher A; Xia, Xiaoxia; Kelly, Sandra J

2012-10-01

Some of the most frequent deficits seen in children with fetal alcohol spectrum disorders (FASD) and in animal models of FASD are spatial memory impairments and impaired executive functioning, which are likely related to alcohol-induced alterations of the hippocampus and prefrontal cortex (PFC), respectively. Choline, a nutrient supplement, has been shown in a rat model to ameliorate some of alcohol's teratogenic effects, and this effect may be mediated through choline's effects on DNA methylation. Alcohol was given by intragastric intubation to rat pups during the neonatal period (postnatal days 2 to 10) (ET group), which is equivalent to the third trimester in humans and a period of heightened vulnerability of the brain to alcohol exposure. Control groups included an intubated control group given the intubation procedure without alcohol (IC) and a nontreated control group (NC). Choline or saline was administered subcutaneously to each subject from postnatal days 2 to 20. On postnatal day 21, the brains of the subjects were removed and assayed for global DNA methylation patterning as measured by chemiluminescence using the cpGlobal assay in both the hippocampal region and PFC. Alcohol exposure caused hypermethylation in the hippocampus and PFC, which was significantly reduced after choline supplementation. In contrast, control animals showed increases in DNA methylation in both regions after choline supplementation, suggesting that choline supplementation has different effects depending upon the initial state of the brain. This study is the first to show changes in global DNA methylation of the hippocampal region and PFC after neonatal alcohol exposure. Choline supplementation impacts global DNA methylation in these 2 brain regions in alcohol-exposed and control animals in a differential manner. The current findings suggest that both alcohol and choline have substantial impact on the epigenome in the PFC and hippocampus, and future studies will be needed to describe which gene families are impacted in such a way that function of the nervous system is changed. Copyright © 2012 by the Research Society on Alcoholism.

Early network activity propagates bidirectionally between hippocampus and cortex.

PubMed

Barger, Zeke; Easton, Curtis R; Neuzil, Kevin E; Moody, William J

2016-06-01

Spontaneous activity in the developing brain helps refine neuronal connections before the arrival of sensory-driven neuronal activity. In mouse neocortex during the first postnatal week, waves of spontaneous activity originating from pacemaker regions in the septal nucleus and piriform cortex propagate through the neocortex. Using high-speed Ca(2+) imaging to resolve the spatiotemporal dynamics of wave propagation in parasagittal mouse brain slices, we show that the hippocampus can act as an additional source of neocortical waves. Some waves that originate in the hippocampus remain restricted to that structure, while others pause at the hippocampus-neocortex boundary and then propagate into the neocortex. Blocking GABAergic neurotransmission decreases the likelihood of wave propagation into neocortex, whereas blocking glutamatergic neurotransmission eliminates spontaneous and evoked hippocampal waves. A subset of hippocampal and cortical waves trigger Ca(2+) waves in astrocytic networks after a brief delay. Hippocampal waves accompanied by Ca(2+) elevation in astrocytes are more likely to propagate into the neocortex. Finally, we show that two structures in our preparation that initiate waves-the hippocampus and the piriform cortex-can be electrically stimulated to initiate propagating waves at lower thresholds than the neocortex, indicating that the intrinsic circuit properties of those regions are responsible for their pacemaker function. © 2015 Wiley Periodicals, Inc.

Auditory cortex of newborn bats is prewired for echolocation.

PubMed

Kössl, Manfred; Voss, Cornelia; Mora, Emanuel C; Macias, Silvio; Foeller, Elisabeth; Vater, Marianne

2012-04-10

Neuronal computation of object distance from echo delay is an essential task that echolocating bats must master for spatial orientation and the capture of prey. In the dorsal auditory cortex of bats, neurons specifically respond to combinations of short frequency-modulated components of emitted call and delayed echo. These delay-tuned neurons are thought to serve in target range calculation. It is unknown whether neuronal correlates of active space perception are established by experience-dependent plasticity or by innate mechanisms. Here we demonstrate that in the first postnatal week, before onset of echolocation and flight, dorsal auditory cortex already contains functional circuits that calculate distance from the temporal separation of a simulated pulse and echo. This innate cortical implementation of a purely computational processing mechanism for sonar ranging should enhance survival of juvenile bats when they first engage in active echolocation behaviour and flight.

Visually evoked responses in extrastriate area MT after lesions of striate cortex in early life.

PubMed

Yu, Hsin-Hao; Chaplin, Tristan A; Egan, Gregory W; Reser, David H; Worthy, Katrina H; Rosa, Marcello G P

2013-07-24

Lesions of striate cortex [primary visual cortex (V1)] in adult primates result in blindness. In contrast, V1 lesions in neonates typically allow much greater preservation of vision, including, in many human patients, conscious perception. It is presently unknown how this marked functional difference is related to physiological changes in cortical areas that are spared by the lesions. Here we report a study of the middle temporal area (MT) of adult marmoset monkeys that received unilateral V1 lesions within 6 weeks of birth. In contrast with observations after similar lesions in adult monkeys, we found that virtually all neurons in the region of MT that was deprived of V1 inputs showed robust responses to visual stimulation. These responses were very similar to those recorded in neurons with receptive fields outside the lesion projection zones in terms of firing rate, signal-to-noise ratio, and latency. In addition, the normal retinotopic organization of MT was maintained. Nonetheless, we found evidence of a very specific functional deficit: direction selectivity, a key physiological characteristic of MT that is known to be preserved in many cells after adult V1 lesions, was absent. These results demonstrate that lesion-induced reorganization of afferent pathways is sufficient to develop robust visual function in primate extrastriate cortex, highlighting a likely mechanism for the sparing of vision after neonatal V1 lesions. However, they also suggest that interactions with V1 in early postnatal life are critical for establishing stimulus selectivity in MT.

Contrast Enhancement without Transient Map Expansion for Species-Specific Vocalizations in Core Auditory Cortex during Learning.

PubMed

Shepard, Kathryn N; Chong, Kelly K; Liu, Robert C

2016-01-01

Tonotopic map plasticity in the adult auditory cortex (AC) is a well established and oft-cited measure of auditory associative learning in classical conditioning paradigms. However, its necessity as an enduring memory trace has been debated, especially given a recent finding that the areal expansion of core AC tuned to a newly relevant frequency range may arise only transiently to support auditory learning. This has been reinforced by an ethological paradigm showing that map expansion is not observed for ultrasonic vocalizations (USVs) or for ultrasound frequencies in postweaning dams for whom USVs emitted by pups acquire behavioral relevance. However, whether transient expansion occurs during maternal experience is not known, and could help to reveal the generality of cortical map expansion as a correlate for auditory learning. We thus mapped the auditory cortices of maternal mice at postnatal time points surrounding the peak in pup USV emission, but found no evidence of frequency map expansion for the behaviorally relevant high ultrasound range in AC. Instead, regions tuned to low frequencies outside of the ultrasound range show progressively greater suppression of activity in response to the playback of ultrasounds or pup USVs for maternally experienced animals assessed at their pups' postnatal day 9 (P9) to P10, or postweaning. This provides new evidence for a lateral-band suppression mechanism elicited by behaviorally meaningful USVs, likely enhancing their population-level signal-to-noise ratio. These results demonstrate that tonotopic map enlargement has limits as a construct for conceptualizing how experience leaves neural memory traces within sensory cortex in the context of ethological auditory learning.

Comparative analysis of Six 3 and Six 6 distribution in the developing and adult mouse brain.

PubMed

Conte, Ivan; Morcillo, Julian; Bovolenta, Paola

2005-11-01

Six 3 and Six 6 genes are two closely related members of the Six/sine oculis family of homeobox containing transcription factors. Their expression and function at early stages of embryonic development has been widely addressed in a variety of species. However, their mRNA distribution during late embryonic, postnatal, and adult brain barely has been analyzed. Here, we show that despite their initial overlap in the anterior neural plate, the expression of Six 3 and Six 6 progressively segregates to different regions during mammalian brain development, maintaining only few areas of partial overlap in the thalamic and hypothalamic regions. Six 3, but not Six 6, is additionally expressed in the olfactory bulb, cerebral cortex, hippocampus, midbrain, and cerebellum. These distinct patterns support the idea that Six 3 and Six 6 are differentially required during forebrain development. Developmental Dynamics 234:718-725, 2005. (c) 2005 Wiley-Liss, Inc.

Cortical Feedback Regulates Feedforward Retinogeniculate Refinement

PubMed Central

Thompson, Andrew D; Picard, Nathalie; Min, Lia; Fagiolini, Michela; Chen, Chinfei

2016-01-01

SUMMARY According to the prevailing view of neural development, sensory pathways develop sequentially in a feedforward manner, whereby each local microcircuit refines and stabilizes before directing the wiring of its downstream target. In the visual system, retinal circuits are thought to mature first and direct refinement in the thalamus, after which cortical circuits refine with experience-dependent plasticity. In contrast, we now show that feedback from cortex to thalamus critically regulates refinement of the retinogeniculate projection during a discrete window in development, beginning at postnatal day 20 in mice. Disrupting cortical activity during this window, pharmacologically or chemogenetically, increases the number of retinal ganglion cells innervating each thalamic relay neuron. These results suggest that primary sensory structures develop through the concurrent and interdependent remodeling of subcortical and cortical circuits in response to sensory experience, rather than through a simple feedforward process. Our findings also highlight an unexpected function for the corticothalamic projection. PMID:27545712

FoxP2 expression in the cerebellum and inferior olive: development of the transverse stripe-shaped expression pattern in the mouse cerebellar cortex.

PubMed

Fujita, Hirofumi; Sugihara, Izumi

2012-02-15

Many molecules are expressed heterogeneously in subpopulations of cerebellar Purkinje cells (PCs) and inferior olive (IO) neurons during development or in adulthood. These expression patterns are often organized in longitudinal stripes in the cerebellar cortex, which may be related to functional compartmentalization. FoxP2, a transcription factor, is expressed in PCs and IO neurons, but the details of its expression pattern remain unclear. Here we examined FoxP2 expression patterns systematically by immunostaining serial sections of the hindbrain from embryonic day 14.5 to adulthood in mice. FoxP2 was highly expressed in virtually all PCs at and before postnatal day 6 (P6), except for those in the flocculus and small parts of the nodulus (vermal lobule X), where FoxP2 expression was moderate or absent. After P6, FoxP2 expression gradually diminished in PCs in some areas. In adults, FoxP2 was expressed, less intensely than in earlier stages, in subsets of PCs that were mostly arranged transversely along the folial apices. In contrast, FoxP2 was expressed intensely in most IO neurons during development and in adulthood. FoxP2 was also expressed in a small population of neurons in the cerebellar nuclei. FoxP2 expression in adult rats and chicks was generally comparable to that in adult mice, suggesting evolutionary conservation of the expression pattern. Thus, the FoxP2 expression pattern reflects new transverse compartmentalization in the adult cerebellar cortex, although its functional significance remains unclear. Copyright © 2011 Wiley-Liss, Inc.

Role of development in reorganization of the SI forelimb-stump representation in fetally, neonatally, and adult amputated rats.

PubMed

Pluto, Charles P; Lane, Richard D; Chiaia, Nicolas L; Stojic, Andrey S; Rhoades, Robert W

2003-09-01

Rats that sustain forelimb removal on postnatal day (P) 0 exhibit numerous multi-unit recording sites in the forelimb-stump representation of primary somatosensory cortex (SI) that also respond to hindlimb stimulation when cortical GABAA+B receptors are blocked. Most of these hindlimb inputs originate in the medial SI hindlimb representation. Although many forelimb-stump sites in these animals respond to hindlimb stimulation, very few respond to stimulation of the face (vibrissae or lower jaw), which is represented in SI just lateral to the forelimb. The lateral to medial development of SI may influence the capacity of hindlimb (but not face) inputs to "invade" the forelimb-stump region in neonatal amputees. The SI forelimb-stump was mapped in adult (>60 days) rats that had sustained amputation on embryonic day (E) 16, on P0, or during adulthood. GABA receptors were blocked and subsequent mapping revealed increases in nonstump inputs in E16 and P0 amputees: fetal amputees exhibited forelimb-stump sites responsive to face (34%), hindlimb (10%), and both (22%); neonatal amputees exhibited 10% face, 39% hindlimb, and 5% both; adult amputees exhibited 10% face, 5% hindlimb, and 0% both, with approximately 80% stump-only sites. These results indicate age-dependent differences in receptive-field reorganization of the forelimb-stump representation, which may reflect the spatiotemporal development of SI. Results from cobalt chloride inactivation of the SI vibrissae region and electrolesioning of the dysgranular cortex suggest that normally suppressed vibrissae inputs to the SI forelimb-stump area originate in the SI vibrissae region and synapse in the dysgranular cortex.

Early valproic acid exposure alters functional organization in the primary visual cortex

PubMed Central

Pohl-Guimaraes, Fernanda; Krahe, Thomas E.; Medina, Alexandre E.

2018-01-01

Epilepsy is one of the most common neurologic disorders and affects 0.5 to 1% of pregnant women. The use of antiepileptic drugs, which is usually continued throughout pregnancy, can cause in offspring mild to severe sensory deficits. Neuronal selectivity to stimulus orientation is a basic functional property of the visual cortex that is crucial for perception of shapes and borders. Here we investigate the effects of early exposure to valproic acid (Val) and levetiracetam (Lev), commonly used antiepileptic drugs, on the development of cortical neuron orientation selectivity and organization of cortical orientation columns. Ferrets pups were exposed to Val (200 mg/kg), Lev (100 mg/kg) or saline every other day between postnatal day (P) 10 and P30, a period roughly equivalent to the third trimester of human gestation. Optical imaging of intrinsic signals or single-unit recordings were examined at P42–P84, when orientation selectivity in the ferret cortex has reached a mature state. Optical imaging of intrinsic signals revealed decreased contrast of orientation maps in Val-but not Lev- or saline-treated animals. Moreover, single-unit recordings revealed that early Val treatment also reduced orientation selectivity at the cellular level. These findings indicate that Val exposure during a brief period of development disrupts cortical processing of sensory information at a later age and suggest a neurobiological substrate for some types of sensory deficits in fetal anticonvulsant syndrome. PMID:21215743

Early valproic acid exposure alters functional organization in the primary visual cortex.

PubMed

Pohl-Guimaraes, Fernanda; Krahe, Thomas E; Medina, Alexandre E

2011-03-01

Epilepsy is one of the most common neurologic disorders and affects 0.5 to 1% of pregnant women. The use of antiepileptic drugs, which is usually continued throughout pregnancy, can cause in offspring mild to severe sensory deficits. Neuronal selectivity to stimulus orientation is a basic functional property of the visual cortex that is crucial for perception of shapes and borders. Here we investigate the effects of early exposure to valproic acid (Val) and levetiracetam (Lev), commonly used antiepileptic drugs, on the development of cortical neuron orientation selectivity and organization of cortical orientation columns. Ferrets pups were exposed to Val (200mg/kg), Lev (100mg/kg) or saline every other day between postnatal day (P) 10 and P30, a period roughly equivalent to the third trimester of human gestation. Optical imaging of intrinsic signals or single-unit recordings were examined at P42-P84, when orientation selectivity in the ferret cortex has reached a mature state. Optical imaging of intrinsic signals revealed decreased contrast of orientation maps in Val- but not Lev- or saline-treated animals. Moreover, single-unit recordings revealed that early Val treatment also reduced orientation selectivity at the cellular level. These findings indicate that Val exposure during a brief period of development disrupts cortical processing of sensory information at a later age and suggest a neurobiological substrate for some types of sensory deficits in fetal anticonvulsant syndrome. Copyright © 2011 Elsevier Inc. All rights reserved.

Late onset deficits in synaptic plasticity in the valproic acid rat model of autism.

PubMed

Martin, Henry G S; Manzoni, Olivier J

2014-01-01

Valproic acid (VPA) is a frequently used drug in the treatment of epilepsy, bipolar disorders and migraines; however it is also a potent teratogen. Prenatal exposure increases the risk of childhood malformations and can result in cognitive deficits. In rodents in utero exposure to VPA also causes neurodevelopmental abnormalities and is an important model of autism. In early postnatal life VPA exposed rat pups show changes in medial prefrontal cortex (mPFC) physiology and synaptic connectivity. Specifically, principal neurons show decreased excitability but increased local connectivity, coupled with an increase in long-term potentiation (LTP) due to an up-regulation of NMDA receptor (NMDAR) expression. However recent evidence suggests compensatory homeostatic mechanisms lead to normalization of synaptic NMDARs during later postnatal development. Here we have extended study of mPFC synaptic physiology into adulthood to better understand the longitudinal consequences of early developmental abnormalities in VPA exposed rats. Surprisingly in contrast to early postnatal life and adolescence, we find that adult VPA exposed rats show reduced synaptic function. Both NMDAR mediated currents and LTP are lower in adult VPA rats, although spontaneous activity and endocannabinoid dependent long-term depression are normal. We conclude that rather than correcting, synaptic abnormalities persist into adulthood in VPA exposed rats, although a quite different synaptic phenotype is present. This switch from hyper to hypo function in mPFC may be linked to some of the neurodevelopmental defects found in prenatal VPA exposure and autism spectrum disorders in general.

Transcriptional and electrophysiological maturation of neocortical fastspiking GABAergic interneurons

PubMed Central

Okaty, Benjamin W; Miller, Mark N; Sugino, Ken; Hempel, Chris M; Nelson, Sacha B

2009-01-01

Fast-spiking (FS) interneurons are important elements of neocortical circuitry that constitute the primary source of synaptic inhibition in adult cortex and impart temporal organization on ongoing cortical activity. The highly specialized intrinsic membrane and firing properties that allow cortical FS interneurons to perform these functions are due to equally specialized gene expression, which is ultimately coordinated by cell-type-specific transcriptional regulation. While embryonic transcriptional events govern the initial steps of cell-type specification in most cortical interneurons, including FS cells, the electrophysiological properties that distinguish adult cortical cell types emerge relatively late in postnatal development, and the transcriptional events that drive this maturational process are not known. To address this, we used mouse whole-genome microarrays and whole-cell patch clamp to characterize the transcriptional and electrophysiological maturation of cortical FS interneurons between postnatal day 7 (P7) and P40. We found that the intrinsic and synaptic physiology of FS cells undergoes profound regulation over the first four postnatal weeks, and that these changes are correlated with largely monotonic but bidirectional transcriptional regulation of thousands of genes belonging to multiple functional classes. Using our microarray screen as a guide, we discovered that upregulation of 2-pore K+ leak channels between P10 and P25 contributes to one of the major differences between the intrinsic membrane properties of immature and adult FS cells, and found a number of other candidate genes that likely confer cell-type specificity on mature FS cells. PMID:19474331

Focal Stroke in the Developing Rat Motor Cortex Induces Age- and Experience-Dependent Maladaptive Plasticity of Corticospinal System

PubMed Central

Gennaro, Mariangela; Mattiello, Alessandro; Mazziotti, Raffaele; Antonelli, Camilla; Gherardini, Lisa; Guzzetta, Andrea; Berardi, Nicoletta; Cioni, Giovanni; Pizzorusso, Tommaso

2017-01-01

Motor system development is characterized by an activity-dependent competition between ipsilateral and contralateral corticospinal tracts (CST). Clinical evidence suggests that age is crucial for developmental stroke outcome, with early lesions inducing a “maladaptive” strengthening of ipsilateral projections from the healthy hemisphere and worse motor impairment. Here, we investigated in developing rats the relation between lesion timing, motor outcome and CST remodeling pattern. We induced a focal ischemia into forelimb motor cortex (fM1) at two distinct pre-weaning ages: P14 and P21. We compared long-term motor outcome with changes in axonal sprouting of contralesional CST at red nucleus and spinal cord level using anterograde tracing. We found that P14 stroke caused a more severe long-term motor impairment than at P21, and induced a strong and aberrant contralesional CST sprouting onto denervated spinal cord and red nucleus. The mistargeted sprouting of CST, and the worse motor outcome of the P14 stroke rats were reversed by an early skilled motor training, underscoring the potential of early activity-dependent plasticity in modulating lesion outcome. Thus, changes in the mechanisms controlling CST plasticity occurring during the third postnatal week are associated with age-dependent regulation of the motor outcome after stroke. PMID:28706475

Focal Stroke in the Developing Rat Motor Cortex Induces Age- and Experience-Dependent Maladaptive Plasticity of Corticospinal System.

PubMed

Gennaro, Mariangela; Mattiello, Alessandro; Mazziotti, Raffaele; Antonelli, Camilla; Gherardini, Lisa; Guzzetta, Andrea; Berardi, Nicoletta; Cioni, Giovanni; Pizzorusso, Tommaso

2017-01-01

Motor system development is characterized by an activity-dependent competition between ipsilateral and contralateral corticospinal tracts (CST). Clinical evidence suggests that age is crucial for developmental stroke outcome, with early lesions inducing a "maladaptive" strengthening of ipsilateral projections from the healthy hemisphere and worse motor impairment. Here, we investigated in developing rats the relation between lesion timing, motor outcome and CST remodeling pattern. We induced a focal ischemia into forelimb motor cortex (fM1) at two distinct pre-weaning ages: P14 and P21. We compared long-term motor outcome with changes in axonal sprouting of contralesional CST at red nucleus and spinal cord level using anterograde tracing. We found that P14 stroke caused a more severe long-term motor impairment than at P21, and induced a strong and aberrant contralesional CST sprouting onto denervated spinal cord and red nucleus. The mistargeted sprouting of CST, and the worse motor outcome of the P14 stroke rats were reversed by an early skilled motor training, underscoring the potential of early activity-dependent plasticity in modulating lesion outcome. Thus, changes in the mechanisms controlling CST plasticity occurring during the third postnatal week are associated with age-dependent regulation of the motor outcome after stroke.

Experience-dependent emergence of beta and gamma band oscillations in the primary visual cortex during the critical period

PubMed Central

Chen, Guang; Rasch, Malte J.; Wang, Ran; Zhang, Xiao-hui

2015-01-01

Neural oscillatory activities have been shown to play important roles in neural information processing and the shaping of circuit connections during development. However, it remains unknown whether and how specific neural oscillations emerge during a postnatal critical period (CP), in which neuronal connections are most substantially modified by neural activity and experience. By recording local field potentials (LFPs) and single unit activity in developing primary visual cortex (V1) of head-fixed awake mice, we here demonstrate an emergence of characteristic oscillatory activities during the CP. From the pre-CP to CP, the peak frequency of spontaneous fast oscillatory activities shifts from the beta band (15–35 Hz) to the gamma band (40–70 Hz), accompanied by a decrease of cross-frequency coupling (CFC) and broadband spike-field coherence (SFC). Moreover, visual stimulation induced a large increase of beta-band activity but a reduction of gamma-band activity specifically from the CP onwards. Dark rearing of animals from the birth delayed this emergence of oscillatory activities during the CP, suggesting its dependence on early visual experience. These findings suggest that the characteristic neuronal oscillatory activities emerged specifically during the CP may represent as neural activity trait markers for the experience-dependent maturation of developing visual cortical circuits. PMID:26648548

Mild prenatal protein malnutrition increases alpha2C-adrenoceptor density in the cerebral cortex during postnatal life and impairs neocortical long-term potentiation and visuo-spatial performance in rats.

PubMed

Soto-Moyano, Rubén; Valladares, Luis; Sierralta, Walter; Pérez, Hernán; Mondaca, Mauricio; Fernández, Victor; Burgos, Héctor; Hernández, Alejandro

2005-06-01

Mild reduction in the protein content of the mother's diet from 25 to 8% casein, calorically compensated by carbohydrates, does not alter body and brain weights of rat pups at birth, but leads to significant enhancements in the concentration and release of cortical noradrenaline during early postnatal life. Since central noradrenaline and some of its receptors are critically involved in long-term potentiation (LTP) and memory formation, this study evaluated the effect of mild prenatal protein malnutrition on the alpha2C-adrenoceptor density in the frontal and occipital cortices, induction of LTP in the same cortical regions and the visuo-spatial memory. Pups born from rats fed a 25% casein diet throughout pregnancy served as controls. At day 8 of postnatal age, prenatally malnourished rats showed a threefold increase in neocortical alpha2C-adrenoceptor density. At 60 days-of-age, alpha2C-adrenoceptor density was still elevated in the neocortex, and the animals were unable to maintain neocortical LTP and presented lower visuo-spatial memory performance. Results suggest that overexpression of neocortical alpha2C-adrenoceptors during postnatal life, subsequent to mild prenatal protein malnutrition, could functionally affect the synaptic networks subserving neocortical LTP and visuo-spatial memory formation.

Fluoride and arsenic exposure affects spatial memory and activates the ERK/CREB signaling pathway in offspring rats.

PubMed

Zhu, Yu-Peng; Xi, Shu-Hua; Li, Ming-Yan; Ding, Ting-Ting; Liu, Nan; Cao, Fu-Yuan; Zeng, Yang; Liu, Xiao-Jing; Tong, Jun-Wang; Jiang, Shou-Fang

2017-03-01

Fluoride and arsenic are inorganic contaminants that occur in the natural environment. Chronic fluoride and/or arsenic exposure can induce developmental neurotoxicity and negatively influence intelligence in children, although the underlying molecular mechanisms are poorly understood. This study explored the effects of fluoride and arsenic exposure in drinking water on spatial learning, memory and key protein expression in the ERK/CREB signaling pathway in hippocampal and cerebral cortex tissue in rat offspring. Pregnant rats were divided into four groups. Control rats drank tap water, while rats in the three exposure groups drank water with sodium fluoride (100mg/L), sodium arsenite (75mg/L), and a sodium fluoride (100mg/L) and sodium arsenite (75mg/L) combination during gestation and lactation. After weaning, rat pups drank the same solution as their mothers. Spatial learning and memory ability of pups at postnatal day 21 (PND21) and postnatal day 42 (PND42) were measured using a Morris water maze. ERK, phospho-ERK (p-ERK), CREB and phospho-CREB (p-CREB) protein expression in the hippocampus and cerebral cortex was detected using Western blot. Compared with the control pups, escape latencies increased in PND42 pups exposed to arsenic and co-exposed to fluoride and arsenic, and the short-term and long-term spatial memory ability declined in pups exposed to fluoride and arsenic, both alone and in combination. Compared with controls, ERK and p-ERK levels decreased in the hippocampus and cerebral cortex in pups exposed to combined fluoride and arsenic. CREB protein expression in the cerebral cortex decreased in pups exposed to fluoride, arsenic, and the fluoride and arsenic combination. p-CREB protein expression in both the hippocampus and cerebral cortex was decreased in pups exposed to fluoride and arsenic in combination compared to the control group. There were negative correlation between the proteins expression and escape latency periods in pups. These data indicate that exposure to fluoride and arsenic in early life stage changes ERK, p-ERK, CREB and p-CREB protein expression in the hippocampus and cerebral cortex of rat offspring at PND21 and PND 42, which may contribute to impaired neurodevelopment following exposure. Copyright © 2017 Elsevier B.V. All rights reserved.

Prenatal Nutritional Deficiency Reprogrammed Postnatal Gene Expression in Mammal Brains: Implications for Schizophrenia

PubMed Central

Xu, Jiawei; He, Guang; Zhu, Jingde; Zhou, Xinyao; St Clair, David; Wang, Teng; Xiang, Yuqian; Zhao, Qingzhu; Xing, Qinghe; Liu, Yun; Wang, Lei; Li, Qiaoli

2015-01-01

Background: Epidemiological studies have identified prenatal exposure to famine as a risk factor for schizophrenia, and animal models of prenatal malnutrition display structural and functional brain abnormalities implicated in schizophrenia. Methods: The offspring of the RLP50 rat, a recently developed animal model of prenatal famine malnutrition exposure, was used to investigate the changes of gene expression and epigenetic modifications in the brain regions. Microarray gene expression analysis was carried out in the prefrontal cortex and the hippocampus from 8 RLP50 offspring rats and 8 controls. MBD-seq was used to test the changes in DNA methylation in hippocampus depending on prenatal malnutrition exposure. Results: In the prefrontal cortex, offspring of RLP50 exhibit differences in neurotransmitters and olfactory-associated gene expression. In the hippocampus, the differentially-expressed genes are related to synaptic function and transcription regulation. DNA methylome profiling of the hippocampus also shows widespread but systematic epigenetic changes; in most cases (87%) this involves hypermethylation. Remarkably, genes encoded for the plasma membrane are significantly enriched for changes in both gene expression and DNA methylome profiling screens (p = 2.37×10–9 and 5.36×10–9, respectively). Interestingly, Mecp2 and Slc2a1, two genes associated with cognitive impairment, show significant down-regulation, and Slc2a1 is hypermethylated in the hippocampus of the RLP50 offspring. Conclusions: Collectively, our results indicate that prenatal exposure to malnutrition leads to the reprogramming of postnatal brain gene expression and that the epigenetic modifications contribute to the reprogramming. The process may impair learning and memory ability and result in higher susceptibility to schizophrenia. PMID:25522397

Contribution of NMDA receptor hypofunction in prefrontal and cortical excitatory neurons to schizophrenia-like phenotypes.

PubMed

Rompala, Gregory R; Zsiros, Veronika; Zhang, Shuqin; Kolata, Stefan M; Nakazawa, Kazu

2013-01-01

Pharmacological and genetic studies support a role for NMDA receptor (NMDAR) hypofunction in the etiology of schizophrenia. We have previously demonstrated that NMDAR obligatory subunit 1 (GluN1) deletion in corticolimbic interneurons during early postnatal development is sufficient to confer schizophrenia-like phenotypes in mice. However, the consequence of NMDAR hypofunction in cortical excitatory neurons is not well delineated. Here, we characterize a conditional knockout mouse strain (CtxGluN1 KO mice), in which postnatal GluN1 deletion is largely confined to the excitatory neurons in layer II/III of the medial prefrontal cortex and sensory cortices, as evidenced by the lack of GluN1 mRNA expression in in situ hybridization immunocytochemistry as well as the lack of NMDA currents with in vitro recordings. Mutants were impaired in prepulse inhibition of the auditory startle reflex as well as object-based short-term memory. However, they did not exhibit impairments in additional hallmarks of schizophrenia-like phenotypes (e.g. spatial working memory, social behavior, saccharine preference, novelty and amphetamine-induced hyperlocomotion, and anxiety-related behavior). Furthermore, upon administration of the NMDA receptor antagonist, MK-801, there were no differences in locomotor activity versus controls. The mutant mice also showed negligible levels of reactive oxygen species production following chronic social isolation, and recording of miniature-EPSC/IPSCs from layer II/III excitatory neurons in medial prefrontal cortex suggested no alteration in GABAergic activity. All together, the mutant mice displayed cognitive deficits in the absence of additional behavioral or cellular phenotypes reflecting schizophrenia pathophysiology. Thus, NMDAR hypofunction in prefrontal and cortical excitatory neurons may recapitulate only a cognitive aspect of human schizophrenia symptoms.

Effects of postnatal dietary choline manipulation against MK-801 neurotoxicity in pre- and postadolescent rats.

PubMed

Biasi, Elisabetta

2010-11-29

Prenatal supplementation of rat dams with dietary choline has been shown to provide their offspring with neuroprotection against N-methyl-d-aspartate (NMDA) antagonist-mediated neurotoxicity. This study investigated whether postnatal dietary choline supplementation exposure for 30 and 60 days of rats starting in a pre-puberty age would also induce neuroprotection (without prenatal exposure). Male and female Sprague-Dawley rats (postnatal day 30 of age) were reared for 30 or 60 concurrent days on one of the four dietary levels of choline: 1) fully deficient choline, 2) 1/3 the normal level, 3) the normal level, or 4) seven times the normal level. After diet treatment, the rats received one injection of MK-801 (dizocilpine 3mg/kg) or saline control. Seventy-two hours later, the rats were anesthetized and transcardially perfused. Their brains were then postfixed for histology with Fluorojade-C (FJ-C) staining. Serial coronal sections were prepared from a rostrocaudal direction from 1.80 to 4.2mm posterior to the bregma to examine cell degeneration in the retrosplenial and piriform regions. MK-801, but not control saline, produced significant numbers of FJ-C positive neurons, indicating considerable neuronal degeneration. Dietary choline supplementation or deprivation in young animals reared for 30-60days did not alter NMDA antagonist-induced neurodegeneration in the retrosplenial region. An interesting finding is the absence of the piriform cortex involvement in young male rats and the complete absence of neurotoxicity in both hippocampus regions and DG. However, neurotoxicity in the piriform cortex of immature females treated for 60days appeared to be suppressed by low levels of dietary choline. Published by Elsevier B.V.

Motor cortex electrical stimulation augments sprouting of the corticospinal tract and promotes recovery of motor function

PubMed Central

Carmel, Jason B.; Martin, John H.

2014-01-01

The corticospinal system—with its direct spinal pathway, the corticospinal tract (CST) – is the primary system for controlling voluntary movement. Our approach to CST repair after injury in mature animals was informed by our finding that activity drives establishment of connections with spinal cord circuits during postnatal development. After incomplete injury in maturity, spared CST circuits sprout, and partially restore lost function. Our approach harnesses activity to augment this injury-dependent CST sprouting and to promote function. Lesion of the medullary pyramid unilaterally eliminates all CST axons from one hemisphere and allows examination of CST sprouting from the unaffected hemisphere. We discovered that 10 days of electrical stimulation of either the spared CST or motor cortex induces CST axon sprouting that partially reconstructs the lost CST. Stimulation also leads to sprouting of the cortical projection to the magnocellular red nucleus, where the rubrospinal tract originates. Coordinated outgrowth of the CST and cortical projections to the red nucleus could support partial re-establishment of motor systems connections to the denervated spinal motor circuits. Stimulation restores skilled motor function in our animal model. Lesioned animals have a persistent forelimb deficit contralateral to pyramidotomy in the horizontal ladder task. Rats that received motor cortex stimulation either after acute or chronic injury showed a significant functional improvement that brought error rate to pre-lesion control levels. Reversible inactivation of the stimulated motor cortex reinstated the impairment demonstrating the importance of the stimulated system to recovery. Motor cortex electrical stimulation is an effective approach to promote spouting of spared CST axons. By optimizing activity-dependent sprouting in animals, we could have an approach that can be translated to the human for evaluation with minimal delay. PMID:24994971

Cytidine-5-diphosphocholine supplement in early life induces stable increase in dendritic complexity of neurons in the somatosensory cortex of adult rats

PubMed Central

Rema, V.; Bali, K.K.; Ramachandra, R.; Chugh, M.; Darokhan, Z.; Chaudhary, R.

2008-01-01

Cytidine-5-diphosphocholine (CDP-choline or citicholine) is an essential molecule that is required for biosynthesis of cell membranes. In adult humans it is used as a memory-enhancing drug for treatment of age-related dementia and cerebrovascular conditions. However the effect of CDP-choline on perinatal brain is not known. We administered CDP-choline to Long Evans rats each day from conception (maternal ingestion) to postnatal day 60 (P60). Pyramidal neurons from supragranular layers 2/3, granular layer 4 and infragranular layer 5 of somatosensory cortex were examined with Golgi–Cox staining at P240. CDP-choline treatment significantly increased length and branch points of apical and basal dendrites. Sholl analysis shows that the complexity of apical and basal dendrites of neurons is maximal in layers 2/3 and layer 5. In layer 4 significant increases were seen in basilar dendritic arborization. CDP-choline did not increase the number of primary basal dendrites on neurons in the somatosensory cortex. Primary cultures from somatosensory cortex were treated with CDP-choline to test its effect on neuronal survival. CDP-choline treatment neither enhanced the survival of neurons in culture nor increased the number of neurites. However significant increases in neurite length, branch points and total area occupied by the neurons were observed. We conclude that exogenous supplementation of CDP-choline during development causes stable changes in neuronal morphology. Significant increase in dendritic growth and branching of pyramidal neurons from the somatosensory cortex resulted in enlarging the surface area occupied by the neurons which we speculate will augment processing of sensory information. PMID:18619738

Development of Columnar Topography in the Excitatory Layer 4 to Layer 2/3 Projection in Rat Barrel Cortex

PubMed Central

Bender, Kevin J.; Rangel, Juliana; Feldman, Daniel E.

2011-01-01

The excitatory feedforward projection from layer (L) 4 to L2/3 in rat primary somatosensory (S1) cortex exhibits precise, columnar topography that is critical for columnar processing of whisker inputs. Here, we characterize the development of axonal topography in this projection using single-cell reconstructions in S1 slices. In the mature projection [postnatal day (P) 14 –26], axons of L4 cells extending into L2/3 were confined almost entirely to the home barrel column, consistent with previous results. At younger ages (P8 –11), however, axonal topography was significantly less columnar, with a large proportion of branches innervating neighboring barrel columns representing adjacent whisker rows. Mature topography developed from this initial state by targeted axonal growth within the home column and by growth of barrel columns themselves. Raising rats with all or a subset of whiskers plucked from P8 –9, manipulations that induce reorganization of functional whisker maps and synaptic depression at L4 to L2/3 synapses, did not alter normal anatomical development of L4 to L2/3 axons. Thus, development of this projection does not require normal sensory experience after P8, and deprivation-induced reorganization of whisker maps at this age is unlikely to involve physical remodeling of L4 to L2/3 axons. PMID:14507976

Spatiotemporal expression of MANF in the developing rat brain.

PubMed

Wang, Haiping; Ke, Zunji; Alimov, Alexander; Xu, Mei; Frank, Jacqueline A; Fang, Shengyun; Luo, Jia

2014-01-01

Mesencephalic astrocyte-derived neurotrophic factor (MANF) is an evolutionarily conserved neurotrophic factor which exhibited neuroprotective properties. Recent studies suggested that MANF may play a role in the neural development of Drosophila and zebra fishes. In this study, we investigated the spatiotemporal expression of MANF in the brain of postnatal and adult rats. MANF expression appeared wide spread and mainly localized in neurons. In the cerebral cortex, neurons in layer IV and VI displayed particularly strong MANF immunoreactivity. In the hippocampus, intensive MANF expression was observed throughout the subfields of Cornu Amonis (CA1, CA2, and CA3) and the granular layer of the dentate gyrus (DG). In the substantia nigra, high MANF expression was shown in the substantia nigra pars compacta (SNpc). In the thalamus, the anterodorsal thalamic nucleus (ADTN) exhibited the highest MANF immunoreactivity. In the hypothalamus, intensive MANF immunoreactivity was shown in the supraoptic nucleus (SON) and tuberomammillary nucleus (TMN). In the cerebellum, MANF was localized in the external germinal layer (EGL), Purkinje cell layer (PCL), internal granule layer (IGL) and the deep cerebellar nuclei (DCN). We examined the developmental expression of MANF on postnatal day (PD) 3, 5, 7, 9, 15, 21, 30 and adulthood. In general, the levels of MANF were high in the early PDs (PD3 and PD5), and declined gradually as the brain matured; MANF expression in the adult brain was the lowest among all time points examined. However, in some structures, such as PCL, IGL, SON, TMN and locus coeruleus (LC), high expression of MANF sustained throughout the postnatal period and persisted into adulthood. Our results indicated that MANF was developmentally regulated and may play a role in the maturation of the central nervous system (CNS).

Spatiotemporal Expression of MANF in the Developing Rat Brain

PubMed Central

Wang, Haiping; Ke, Zunji; Alimov, Alexander; Xu, Mei; Frank, Jacqueline A.; Fang, Shengyun; Luo, Jia

2014-01-01

Mesencephalic astrocyte-derived neurotrophic factor (MANF) is an evolutionarily conserved neurotrophic factor which exhibited neuroprotective properties. Recent studies suggested that MANF may play a role in the neural development of Drosophila and zebra fishes. In this study, we investigated the spatiotemporal expression of MANF in the brain of postnatal and adult rats. MANF expression appeared wide spread and mainly localized in neurons. In the cerebral cortex, neurons in layer IV and VI displayed particularly strong MANF immunoreactivity. In the hippocampus, intensive MANF expression was observed throughout the subfields of Cornu Amonis (CA1, CA2, and CA3) and the granular layer of the dentate gyrus (DG). In the substantia nigra, high MANF expression was shown in the substantia nigra pars compacta (SNpc). In the thalamus, the anterodorsal thalamic nucleus (ADTN) exhibited the highest MANF immunoreactivity. In the hypothalamus, intensive MANF immunoreactivity was shown in the supraoptic nucleus (SON) and tuberomammillary nucleus (TMN). In the cerebellum, MANF was localized in the external germinal layer (EGL), Purkinje cell layer (PCL), internal granule layer (IGL) and the deep cerebellar nuclei (DCN). We examined the developmental expression of MANF on postnatal day (PD) 3, 5, 7, 9, 15, 21, 30 and adulthood. In general, the levels of MANF were high in the early PDs (PD3 and PD5), and declined gradually as the brain matured; MANF expression in the adult brain was the lowest among all time points examined. However, in some structures, such as PCL, IGL, SON, TMN and locus coeruleus (LC), high expression of MANF sustained throughout the postnatal period and persisted into adulthood. Our results indicated that MANF was developmentally regulated and may play a role in the maturation of the central nervous system (CNS). PMID:24587361

Postnatal LPS Challenge Impacts Escape Learning and Expression of Plasticity Factors Mmp9 and Timp1 in Rats: Effects of Repeated Training.

PubMed

Trofimov, Alexander; Strekalova, Tatyana; Mortimer, Niall; Zubareva, Olga; Schwarz, Alexander; Svirin, Evgeniy; Umriukhin, Aleksei; Svistunov, Andrei; Lesch, Klaus-Peter; Klimenko, Victor

2017-08-01

Bacterial intoxication associated with inflammatory conditions during development can impair brain functions, in particular evolutionarily novel forms of memory, such as explicit learning. Little is known about the dangers of early-life inflammation on more basic forms of learning, for example, the acquisition of motor escape abilities, which are generally better preserved under pathological conditions. To address this limitation in knowledge, an inflammatory response was elicited in Wistar pups by lipopolysaccharide (LPS) injections (25 μg/kg) on postnatal days P15, P18 and P21. The acquisition of escape behaviour was tested from P77 by active avoidance footshock model and water maze. Open-field behaviour and blood corticosterone levels were also measured. Rat brain tissue was collected from pups 2 h post-injection and from adult rats which either underwent escape training on P77-P81 or remained untrained. mRNA levels of developmental brain plasticity factors MMP-9 and TIMP-1 were investigated in the medial prefrontal cortex and ventral/dorsal hippocampus. LPS-challenged rats displayed moderately deficient escape responses in both memory tests, increased freezing behaviour and, surprisingly, reduced blood cortisol levels. Mmp9 and Timp1, and their ratio to one another, were differentially altered in pups versus adult untrained rats but remained unchanged overall in rats trained in either learning task. Together, our data indicate that systemic pro-inflammatory response during early postnatal development has long-lasting effects, including on the acquisition of motor escape abilities and plasticity factor expression, into adulthood. Our data suggest that altered stress response could possibly mediate these deviations and repeated training might generate positive effects on plasticity under the employed conditions.

Neonatal Sleep Restriction Increases Nociceptive Sensitivity in Adolescent Mice.

PubMed

Araujo, Paula; Coelho, Cesar A; Oliveira, Maria G; Tufik, Sergio; Andersen, Monica L

2018-03-01

Sleep loss in infants may have a negative effect on the functional and structural development of the nociceptive system. We tested the hypothesis that neonatal sleep restriction induces a long-term increase of pain-related behaviors in mice and that this hypersensitivity occurs due to changes in the neuronal activity of nociceptive pathways. We aim to investigate the effects of sleep loss in neonatal mice on pain behaviors of adolescent and adult mice in a sex-dependent manner. We also analyzed neuroanatomical and functional changes in pain pathways associated with behavioral changes. An experimental animal study. A basic sleep research laboratory at Universidade Federal de São Paulo in Brazil. Neonatal mice at postnatal day (PND) 12 were randomly assigned to either control (CTRL), maternal separation (MS), or sleep restriction (SR) groups. MS and SR were performed 2 hours a day for 10 days (PND 12 until PND 21). The gentle handling method was used to prevent sleep. At PND 21, PND 35, or PND 90, the mice were tested for pain-related behaviors. Their brains were harvested and immunohistochemically stained for c-Fos protein in the anterior cingulate cortex, primary somatosensory cortex, and periaqueductal gray (PAG). Neonatal SR significantly increased nociceptive sensitivity in the hot plate test in adolescent mice (-23.5% of pain threshold). This alteration in nociceptive response was accompanied by a decrease in c-Fos expression in PAG (-40% of c-Fos positive cells compared to the CTRL group). The hypersensitivity found in adolescent mice was not present in adult animals, and all mice showed a comparable nociceptive response. Even using a mild manipulation method, in which a minimal amount of handling was applied to maintain wakefulness, sleep deprivation was a stressful event evidenced by higher corticosterone levels. Repeated exposures to sleep loss during early life were able to induce changes in the nociceptive response associated with alterations in neural activity in descending control of pain. Brain maturation, hypersensitivity, neuronal activity, nociception, pain, periaqueductal gray, postnatal development, sleep, sleep deprivation.

DKK1 mediated inhibition of Wnt signaling in postnatal mice leads to loss of TEC progenitors and thymic degeneration.

PubMed

Osada, Masako; Jardine, Logan; Misir, Ruth; Andl, Thomas; Millar, Sarah E; Pezzano, Mark

2010-02-08

Thymic epithelial cell (TEC) microenvironments are essential for the recruitment of T cell precursors from the bone marrow, as well as the subsequent expansion and selection of thymocytes resulting in a mature self-tolerant T cell repertoire. The molecular mechanisms, which control both the initial development and subsequent maintenance of these critical microenvironments, are poorly defined. Wnt signaling has been shown to be important to the development of several epithelial tissues and organs. Regulation of Wnt signaling has also been shown to impact both early thymocyte and thymic epithelial development. However, early blocks in thymic organogenesis or death of the mice have prevented analysis of a role of canonical Wnt signaling in the maintenance of TECs in the postnatal thymus. Here we demonstrate that tetracycline-regulated expression of the canonical Wnt inhibitor DKK1 in TECs localized in both the cortex and medulla of adult mice, results in rapid thymic degeneration characterized by a loss of DeltaNP63(+) Foxn1(+) and Aire(+) TECs, loss of K5K8DP TECs thought to represent or contain an immature TEC progenitor, decreased TEC proliferation and the development of cystic structures, similar to an aged thymus. Removal of DKK1 from DKK1-involuted mice results in full recovery, suggesting that canonical Wnt signaling is required for the differentiation or proliferation of TEC populations needed for maintenance of properly organized adult thymic epithelial microenvironments. Taken together, the results of this study demonstrate that canonical Wnt signaling within TECs is required for the maintenance of epithelial microenvironments in the postnatal thymus, possibly through effects on TEC progenitor/stem cell populations. Downstream targets of Wnt signaling, which are responsible for maintenance of these TEC progenitors may provide useful targets for therapies aimed at counteracting age associated thymic involution or the premature thymic degeneration associated with cancer therapy and bone marrow transplants.

Understanding the Etiology of Tuberous Sclerosis Complex

DTIC Science & Technology

2011-07-01

heterotopic nodules. Indeed, the cortex of TSC individuals contains pockets of abnormal cells with hyperactive mTOR in an otherwise structurally normal...phosphorylated S6 (phospho-S6). mTOR hyperactivity leads to enhanced S6 phosphorylation. Immunostaining in postnatal day (P) 28 sections from...respectively. In addiiton, hamartin is lost and mTOR hyperactive. Figure 2: In utero single-cell knockout of Tsc1 in cortical cells. (A) Diagram

Postnatal Day 2 to 11 Constitutes a 5-HT-Sensitive Period Impacting Adult mPFC Function

PubMed Central

Rebello, Tahilia J.; Yu, Qinghui; Goodfellow, Nathalie M.; Caffrey Cagliostro, Martha K.; Teissier, Anne; Morelli, Emanuela; Demireva, Elena Y.; Chemiakine, Alexei; Rosoklija, Gorazd B.; Dwork, Andrew J.; Lambe, Evelyn K.; Ansorge, Mark S.

2014-01-01

Early-life serotonin [5-hydroxytryptamine (5-HT)] signaling modulates brain development, which impacts adult behavior, but 5-HT-sensitive periods, neural substrates, and behavioral consequences remain poorly understood. Here we identify the period ranging from postnatal day 2 (P2) to P11 as 5-HT sensitive, with 5-HT transporter (5-HTT) blockade increasing anxiety- and depression-like behavior, and impairing fear extinction learning and memory in adult mice. Concomitantly, P2–P11 5-HTT blockade causes dendritic hypotrophy and reduced excitability of infralimbic (IL) cortex pyramidal neurons that normally promote fear extinction. By contrast, the neighboring prelimbic (PL) pyramidal neurons, which normally inhibit fear extinction, become more excitable. Excitotoxic IL but not PL lesions in adult control mice reproduce the anxiety-related phenotypes. These findings suggest that increased 5-HT signaling during P2–P11 alters adult mPFC function to increase anxiety and impair fear extinction, and imply a differential role for IL and PL neurons in regulating affective behaviors. Together, our results support a developmental mechanism for the etiology and pathophysiology of affective disorders and fear-related behaviors. PMID:25209278

Changes in Lipidome Composition during Brain Development in Humans, Chimpanzees, and Macaque Monkeys

PubMed Central

Li, Qian; Bozek, Katarzyna; Xu, Chuan; Guo, Yanan; Sun, Jing; Pääbo, Svante; Sherwood, Chet C.; Hof, Patrick R.; Ely, John J.; Li, Yan; Willmitzer, Lothar

2017-01-01

Lipids are essential components of the brain. Here, we conducted a comprehensive mass spectrometry-based analysis of lipidome composition in the prefrontal cortex of 40 humans, 40 chimpanzees, and 40 rhesus monkeys over postnatal development and adulthood. Of the 11,772 quantified lipid peaks, 7,589 change significantly along the lifespan. More than 60% of these changes occur prior to adulthood, with less than a quarter associated with myelination progression. Evolutionarily, 36% of the age-dependent lipids exhibit concentration profiles distinct to one of the three species; 488 (18%) of them were unique to humans. In both humans and chimpanzees, the greatest extent of species-specific differences occurs in early development. Human-specific lipidome differences, however, persist over most of the lifespan and reach their peak from 20 to 35 years of age, when compared with chimpanzee-specific ones. PMID:28158622

The mammalian neocortex new pyramidal neuron: a new conception.

PubMed

Marín-Padilla, Miguel

2014-01-06

The new cerebral cortex (neocortex) and the new type of pyramidal neuron are mammalian innovations that have evolved for operating their increasing motor capabilities while essentially using analogous anatomical and neural makeups. The human neocortex starts to develop in 6-week-old embryos with the establishment of a primordial cortical organization, which resembles the primitive cortices of amphibian and reptiles. From the 8th to the 15th week of age, new pyramidal neurons, of ependymal origin, are progressively incorporated within this primordial cortex forming a cellular plate that divides its components into those above it (neocortex first layer) and those below it (neocortex subplate zone). From the 16th week of age to birth and postnatally, the new pyramidal neurons continue to elongate functionally their apical dendrite by adding synaptic membrane to incorporate the needed sensory information for operating its developing motor activities. The new pyramidal neuron' distinguishing feature is the capacity of elongating anatomically and functionally its apical dendrite (its main receptive surface) without losing its original attachment to first layer or the location of its soma and, hence, retaining its essential nature. The number of pyramidal cell functional strata established in the motor cortex increases and reflects each mammalian species motor capabilities: the hedgehog needs two pyramidal cell functional strata to carry out all its motor activities, the mouse 3, cat 4, primates 5 and humans 6. The presence of six pyramidal cell functional strata distinguish the human motor cortex from that of others primates. Homo sapiens represent a new evolutionary stage that have transformed his primate brain for operating his unique motor capabilities, such as speaking, writing, painting, sculpturing and thinking as a premotor activity. Words used in language are the motor expression of thoughts and represent sounds produced by maneuvering the column of expiratory air by coordinated motor quivering as it passes through the larynx, pharynx, mouth, tongue, and lips. Homo sapiens cerebrum has developed new motor centers to communicate mental thoughts (and/or intention) through motor actions.

Effect of antemortem and postmortem factors on ( sup 3 H)MK-801 binding in the human brain: Transient elevation during early childhood

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kornhuber, J.; Mack-Burkhardt, F.; Konradi, C.

1989-01-01

The effect of a number of antemortem and postmortem factors on ({sup 3}H)MK-801 binding was investigated under equilibrium conditions in the frontal cortex of human brains of 38 controls. Binding values transiently increased during the early postnatal period reaching a maximum at the age of about 2 years. After age 10 years ({sup 3}H)MK-801 binding sites disappeared at 5.7% per decade. The storage time of brain tissue had a reducing effect on these binding sites. There was no effect of gender, brain weight or postmortem time interval and the binding sites were bilaterally symmetrically distributed in the frontal cortex.

Social isolation stress and chronic glutathione deficiency have a common effect on the glutamine-to-glutamate ratio and myo-inositol concentration in the mouse frontal cortex.

PubMed

Corcoba, Alberto; Gruetter, Rolf; Do, Kim Q; Duarte, João M N

2017-09-01

Environmental stress can interact with genetic predisposition to increase the risk of developing psychopathology. In this work, we tested the hypothesis that social isolation stress interacts with impaired glutathione synthesis and have cumulative effects on the neurochemical profile of the frontal cortex. A mouse model with chronic glutathione deficit induced by knockout (-/-) of the glutamate-cysteine ligase modulatory subunit (Gclm) was exposed to social isolation stress from weaning to post-natal day 65. Using magnetic resonance methods at high-field (14.1 T), we analysed the neurochemical profile in the frontal cortex, brain size and ventricular volume of adult animals. Glutathione deficit was accompanied by elevated concentrations of N-acetylaspartate, alanine, and glutamine, as well as the ratio of glutamine-to-glutamate (Gln/Glu), and by a reduction in levels of myo-inositol and choline-containing compounds in the frontal cortex of -/- animals with respect to wild-type littermates. Although there was no significant interaction between social isolation stress and glutathione deficiency, mice reared in isolation displayed lower myo-inositol concentration (-8.4%, p < 0.05) and larger Gln/Glu (+7.6%, p < 0.05), relative to those in group housing. Furthermore, glutathione deficiency caused a reduction in whole brain volume and enlargement of ventricles, but social isolation had no effect on these parameters. We conclude that social isolation caused neurochemical alterations that may add to those associated to impaired glutathione synthesis. © 2017 International Society for Neurochemistry.

Selective and Efficient Neural Coding of Communication Signals Depends on Early Acoustic and Social Environment

PubMed Central

Amin, Noopur; Gastpar, Michael; Theunissen, Frédéric E.

2013-01-01

Previous research has shown that postnatal exposure to simple, synthetic sounds can affect the sound representation in the auditory cortex as reflected by changes in the tonotopic map or other relatively simple tuning properties, such as AM tuning. However, their functional implications for neural processing in the generation of ethologically-based perception remain unexplored. Here we examined the effects of noise-rearing and social isolation on the neural processing of communication sounds such as species-specific song, in the primary auditory cortex analog of adult zebra finches. Our electrophysiological recordings reveal that neural tuning to simple frequency-based synthetic sounds is initially established in all the laminae independent of patterned acoustic experience; however, we provide the first evidence that early exposure to patterned sound statistics, such as those found in native sounds, is required for the subsequent emergence of neural selectivity for complex vocalizations and for shaping neural spiking precision in superficial and deep cortical laminae, and for creating efficient neural representations of song and a less redundant ensemble code in all the laminae. Our study also provides the first causal evidence for ‘sparse coding’, such that when the statistics of the stimuli were changed during rearing, as in noise-rearing, that the sparse or optimal representation for species-specific vocalizations disappeared. Taken together, these results imply that a layer-specific differential development of the auditory cortex requires patterned acoustic input, and a specialized and robust sensory representation of complex communication sounds in the auditory cortex requires a rich acoustic and social environment. PMID:23630587

Caveolin1 Identifies a Specific Subpopulation of Cerebral Cortex Callosal Projection Neurons (CPN) Including Dual Projecting Cortical Callosal/Frontal Projection Neurons (CPN/FPN)

PubMed Central

2018-01-01

Abstract The neocortex is composed of many distinct subtypes of neurons that must form precise subtype-specific connections to enable the cortex to perform complex functions. Callosal projection neurons (CPN) are the broad population of commissural neurons that connect the cerebral hemispheres via the corpus callosum (CC). Currently, how the remarkable diversity of CPN subtypes and connectivity is specified, and how they differentiate to form highly precise and specific circuits, are largely unknown. We identify in mouse that the lipid-bound scaffolding domain protein Caveolin 1 (CAV1) is specifically expressed by a unique subpopulation of Layer V CPN that maintain dual ipsilateral frontal projections to premotor cortex. CAV1 is expressed by over 80% of these dual projecting callosal/frontal projection neurons (CPN/FPN), with expression peaking early postnatally as axonal and dendritic targets are being reached and refined. CAV1 is localized to the soma and dendrites of CPN/FPN, a unique population of neurons that shares information both between hemispheres and with premotor cortex, suggesting function during postmitotic development and refinement of these neurons, rather than in their specification. Consistent with this, we find that Cav1 function is not necessary for the early specification of CPN/FPN, or for projecting to their dual axonal targets. CPN subtype-specific expression of Cav1 identifies and characterizes a first molecular component that distinguishes this functionally unique projection neuron population, a population that expands in primates, and is prototypical of additional dual and higher-order projection neuron subtypes. PMID:29379878

FGF-2 induces behavioral recovery after early adolescent injury to the motor cortex of rats.

PubMed

Nemati, Farshad; Kolb, Bryan

2011-11-20

Motor cortex injuries in adulthood lead to poor performance in behavioral tasks sensitive to limb movements in the rat. We have shown previously that motor cortex injury on day 10 or day 55 allow significant spontaneous recovery but not injury in early adolescence (postnatal day 35 "P35"). Previous studies have indicated that injection of basic fibroblast growth factor (FGF-2) enhances behavioral recovery after neonatal cortical injury but such effect has not been studied following motor cortex lesions in early adolescence. The present study undertook to investigate the possibility of such behavioral recovery. Rats with unilateral motor cortex lesions were assigned to two groups in which they received FGF-2 or bovine serum albumin (BSA) and were tested in a number of behavioral tests (postural asymmetry, skilled reaching, sunflower seed manipulation, forepaw inhibition in swimming). Golgi-Cox analysis was used to examine the dendritic structure of pyramidal cells in the animals' parietal (layer III) and forelimb (layer V) area of the cortex. The results indicated that rats injected with FGF-2 (but not BSA) showed significant behavioral recovery that was associated with increased dendritic length and spine density. The present study suggests a role for FGF-2 in the recovery of function following injury during early adolescence. Copyright © 2011 Elsevier B.V. All rights reserved.

The Generation of Superficial Cortical Layers Is Regulated by Levels of the Transcription Factor Pax6

PubMed Central

Manuel, Martine; Price, David J.

2011-01-01

The ventricular zone (VZ) of the embryonic dorsal telencephalon is a major site for generating cortical projection neurons. The transcription factor Pax6 is highly expressed in apical progenitors (APs) residing in the VZ from the earliest stages of corticogenesis. Previous studies mainly focused on Pax6−/− mice have implicated Pax6 in regulating cortical progenitor proliferation, neurogenesis, and formation of superficial cortical layers. We analyzed the developing cortex of PAX77 transgenic mice that overexpress Pax6 in its normal domains of expression. We show that Pax6 overexpression increases cell cycle length of APs and drives the system toward neurogenesis. These effects are specific to late stages of corticogenesis, when superficial layer neurons are normally generated, in cortical regions that express Pax6 at the highest levels. The number of superficial layer neurons is reduced in postnatal PAX77 mice, whereas radial migration and lamina specification of cortical neurons are not affected by Pax6 overexpression. Conditional deletion of Pax6 in cortical progenitors at midstages of corticogenesis, by using a tamoxifen-inducible Emx1-CreER line, affected both numbers and specification of late-born neurons in superficial layers of the mutant cortex. Our analyses suggest that correct levels of Pax6 are essential for normal production of superficial layers of the cortex. PMID:20413449

Contrast Enhancement without Transient Map Expansion for Species-Specific Vocalizations in Core Auditory Cortex during Learning

PubMed Central

Shepard, Kathryn N.; Chong, Kelly K.

2016-01-01

Tonotopic map plasticity in the adult auditory cortex (AC) is a well established and oft-cited measure of auditory associative learning in classical conditioning paradigms. However, its necessity as an enduring memory trace has been debated, especially given a recent finding that the areal expansion of core AC tuned to a newly relevant frequency range may arise only transiently to support auditory learning. This has been reinforced by an ethological paradigm showing that map expansion is not observed for ultrasonic vocalizations (USVs) or for ultrasound frequencies in postweaning dams for whom USVs emitted by pups acquire behavioral relevance. However, whether transient expansion occurs during maternal experience is not known, and could help to reveal the generality of cortical map expansion as a correlate for auditory learning. We thus mapped the auditory cortices of maternal mice at postnatal time points surrounding the peak in pup USV emission, but found no evidence of frequency map expansion for the behaviorally relevant high ultrasound range in AC. Instead, regions tuned to low frequencies outside of the ultrasound range show progressively greater suppression of activity in response to the playback of ultrasounds or pup USVs for maternally experienced animals assessed at their pups’ postnatal day 9 (P9) to P10, or postweaning. This provides new evidence for a lateral-band suppression mechanism elicited by behaviorally meaningful USVs, likely enhancing their population-level signal-to-noise ratio. These results demonstrate that tonotopic map enlargement has limits as a construct for conceptualizing how experience leaves neural memory traces within sensory cortex in the context of ethological auditory learning. PMID:27957529

Spatial distribution and longitudinal development of deep cortical sulcal landmarks in infants.

PubMed

Meng, Yu; Li, Gang; Lin, Weili; Gilmore, John H; Shen, Dinggang

2014-10-15

Sulcal pits, the locally deepest points in sulci of the highly convoluted and variable cerebral cortex, are found to be spatially consistent across human adult individuals. It is suggested that sulcal pits are genetically controlled and have close relationships with functional areas. To date, the existing imaging studies of sulcal pits are mainly focused on adult brains, yet little is known about the spatial distribution and temporal development of sulcal pits in the first 2 years of life, which is the most dynamic and critical period of postnatal brain development. Studying sulcal pits during this period would greatly enrich our limited understandings of the origins and developmental trajectories of sulcal pits, and would also provide important insights into many neurodevelopmental disorders associated with abnormal cortical foldings. In this paper, by using surface-based morphometry, for the first time, we systemically investigated the spatial distribution and temporal development of sulcal pits in major cortical sulci from 73 healthy infants, each with three longitudinal 3T MR scans at term birth, 1 year, and 2 years of age. Our results suggest that the spatially consistent distributions of sulcal pits in major sulci across individuals have already existed at term birth and this spatial distribution pattern keeps relatively stable in the first 2 years of life, despite that the cerebral cortex expands dramatically and the sulcal depth increases considerably during this period. Specially, the depth of sulcal pits increases regionally heterogeneously, with more rapid growth in the high-order association cortex, including the prefrontal and temporal cortices, than the sensorimotor cortex in the first 2 years of life. Meanwhile, our results also suggest that there exist hemispheric asymmetries of the spatial distributions of sulcal pits in several cortical regions, such as the central, superior temporal and postcentral sulci, consistently from birth to 2 years of age, which likely has close relationships with the lateralization of brain functions of these regions. This study provides detailed insights into the spatial distribution and temporal development of deep sulcal landmarks in infants. Copyright © 2014 Elsevier Inc. All rights reserved.

Differential expression of cytoskeletal regulatory factors in the adolescent prefrontal cortex: Implications for cortical development.

PubMed

Shapiro, Lauren P; Parsons, Ryan G; Koleske, Anthony J; Gourley, Shannon L

2017-05-01

The prevalence of depression, anxiety, schizophrenia, and drug and alcohol use disorders peaks during adolescence. Further, up to 50% of "adult" mental health disorders emerge in adolescence. During adolescence, the prefrontal cortex (PFC) undergoes dramatic structural reorganization, in which dendritic spines and synapses are refined, pruned, and stabilized. Understanding the molecular mechanisms that underlie these processes should help to identify factors that influence the development of psychiatric illness. Here we briefly discuss the anatomical connections of the medial and orbital prefrontal cortex (mPFC and OFC, respectively). We then present original findings suggesting that dendritic spines on deep-layer excitatory neurons in the mouse mPFC and OFC prune at different adolescent ages, with later pruning in the OFC. In parallel, we used Western blotting to define levels of several cytoskeletal regulatory proteins during early, mid-, and late adolescence, focusing on tropomyosin-related kinase receptor B (TrkB) and β1-integrin-containing receptors and select signaling partners. We identified regional differences in the levels of several proteins in early and midadolescence that then converged in early adulthood. We also observed age-related differences in TrkB levels, both full-length and truncated isoforms, Rho-kinase 2, and synaptophysin in both PFC subregions. Finally, we identified changes in protein levels in the dorsal and ventral hippocampus that were distinct from those in the PFC. We conclude with a general review of the manner in which TrkB- and β1-integrin-mediated signaling influences neuronal structure in the postnatal brain. Elucidating the role of cytoskeletal regulatory factors throughout adolescence may identify critical mechanisms of PFC development. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Differential expression of cytoskeletal regulatory factors in the adolescent prefrontal cortex: Implications for cortical development

PubMed Central

Shapiro, Lauren P.; Parsons, Ryan G.; Koleske, Anthony J.; Gourley, Shannon L.

2016-01-01

The prevalence of depression, anxiety, schizophrenia, and drug and alcohol use disorders peaks during adolescence. Further, up to 50% of “adult” mental health disorders emerge in adolescence. During adolescence, the prefrontal cortex undergoes dramatic structural reorganization, in which dendritic spines and synapses are refined, pruned, and stabilized. Understanding the molecular mechanisms that underlie these processes should help to identify factors that influence the development of psychiatric illness. Here we briefly discuss the anatomical connections of the medial and orbital prefrontal cortex (mPFC and OFC, respectively). We then present original findings suggesting that dendritic spines on deep-layer excitatory neurons in the mouse mPFC and OFC prune at different adolescent ages, with later pruning in the OFC. In parallel, we used western blotting to define levels of several cytoskeletal regulatory proteins during early, mid-, and late adolescence, focusing on tropomyosin-related kinase receptor B (TrkB) and β1-integrin-containing receptors and select signaling partners. We identified regional differences in the levels of several proteins in early and mid-adolescence that then converged in early adulthood. We also observed age-related differences in TrkB levels, both full-length and truncated isoforms, Rho-kinase 2 (ROCK2), and synaptophysin in both PFC subregions. Finally, we identified changes in protein levels in the dorsal and ventral hippocampus that were distinct from those in the PFC. We conclude with a general review of the manner in which TrkB- and β1-integrin-mediated signaling influences neuronal structure in the postnatal brain. Elucidating the role of cytoskeletal regulatory factors throughout adolescence may identify critical mechanisms of PFC development. PMID:27735056

Effect of 2,450 MHz microwave radiation on the development of the rat brain

DOE Office of Scientific and Technical Information (OSTI.GOV)

Inouye, M.; Galvin, M.J.; McRee, D.I.

1983-12-01

Male Sprague-Dawley rats were exposed to 2,450 MHz microwave radiation at an incident power density of 10 mW/cm2 daily for 3 hours from day 4 of pregnancy (in utero exposure) through day 40 postpartum, except for 2 days at the perinatal period. The animals were killed, and the brains removed, weighed, measured, and histologically examined at 15, 20, 30, and 40 days of age. The histologic parameters examined included the cortical architecture of the cerebral cortex, the decline of the germinal layer along the lateral ventricles, the myelination of the corpus callosum, and the decline of the external germinal layermore » of the cerebellar cortex. In 40-day-old rats, quantitative measurements of neurons were also made. The spine density of the pyramidal cells in layer III of the somatosensory cortex, and the density of basal dendritic trees of the pyramidal cells in layer V were measured in Golgi-Cox impregnated specimens. In addition, the density of Purkinje cells and the extent of the Purkinje cell layer in each lobule were measured in midsagittal sections of the cerebellum stained with thionin. There were no remarkable differences between microwave-exposed and control (sham-irradiated) groups for any of the histologic or quantitative parameters examined; however, the findings provide important information on quantitative measurements of the brain. The data from this study failed to demonstrate that there is a significant effect on rat brain development due to microwave exposure (10 mW/cm2) during the embryonic, fetal, and postnatal periods.« less

Mixed Neurodevelopmental and Neurodegenerative Pathology in Nhe6-Null Mouse Model of Christianson Syndrome

PubMed Central

Xu, Meiyu; Ouyang, Qing; Gong, Jingyi; Pescosolido, Matthew F.; Mishra, Sasmita; Schmidt, Michael; Jones, Richard N.; Gamsiz Uzun, Ece D.; Lizarraga, Sofia B.

2017-01-01

Abstract Christianson syndrome (CS) is an X-linked disorder resulting from loss-of-function mutations in SLC9A6, which encodes the endosomal Na+/H+ exchanger 6 (NHE6). Symptoms include early developmental delay, seizures, intellectual disability, nonverbal status, autistic features, postnatal microcephaly, and progressive ataxia. Neuronal development is impaired in CS, involving defects in neuronal arborization and synaptogenesis, likely underlying diminished brain growth postnatally. In addition to neurodevelopmental defects, some reports have supported neurodegenerative pathology in CS with age. The objective of this study was to determine the nature of progressive changes in the postnatal brain in Nhe6-null mice. We examined the trajectories of brain growth and atrophy in mutant mice from birth until very old age (2 yr). We report trajectories of volume changes in the mutant that likely reflect both brain undergrowth as well as tissue loss. Reductions in volume are first apparent at 2 mo, particularly in the cerebellum, which demonstrates progressive loss of Purkinje cells (PCs). We report PC loss in two distinct Nhe6-null mouse models. More widespread reductions in tissue volumes, namely, in the hippocampus, striatum, and cortex, become apparent after 2 mo, largely reflecting delays in growth with more limited tissue losses with aging. Also, we identify pronounced glial responses, particularly in major fiber tracts such as the corpus callosum, where the density of activated astrocytes and microglia are substantially increased. The prominence of the glial response in axonal tracts suggests a primary axonopathy. Importantly, therefore, our data support both neurodevelopmental and degenerative mechanisms in the pathobiology of CS. PMID:29349289

Neurexin 1 (NRXN1) Splice Isoform Expression During Human Neocortical Development and Aging

PubMed Central

Jenkins, Aaron K.; Paterson, Clare; Wang, Yanhong; Hyde, Thomas M.; Kleinman, Joel E.; Law, Amanda J.

2015-01-01

Neurexin 1 (NRXN1), a presynaptic adhesion molecule, is implicated in several neurodevelopmental disorders characterized by synaptic dysfunction including, autism, intellectual disability, and schizophrenia. To gain insight into NRXN1’s involvement in human cortical development we used quantitative real time PCR to examine the expression trajectories of NRXN1, and its predominant isoforms NRXN1-α and NRXN1-β in prefrontal cortex from fetal stages to aging. Additionally, we investigated whether prefrontal cortical expression levels of NRXN1 transcripts are altered in schizophrenia or bipolar disorder in comparison to non-psychiatric control subjects. We observed that all three NRXN1 transcripts were highly expressed during human fetal cortical development, dramatically increasing with gestational age. In the postnatal DLPFC, expression levels were negatively correlated with age, peaking at birth until approximately 3 years of age, after which levels declined dramatically to be stable across the lifespan. NRXN1-β expression was modestly but significantly elevated in the brains of patients with schizophrenia compared to non-psychiatric controls, whereas NRXN1-α expression was increased in bipolar disorder. These data provide novel evidence that NRXN1 expression is highest in human prefrontal cortex during critical developmental windows relevant to the onset and diagnosis of a range of neurodevelopmental disorders, and that NRXN1 expression may be differentially altered in neuropsychiatric disorders. PMID:26216298

Matrix Metalloproteinase-9 regulates neuronal circuit development and excitability

PubMed Central

Murase, Sachiko; Lantz, Crystal; Kim, Eunyoung; Gupta, Nitin; Higgins, Richard; Stopfer, Mark; Hoffman, Dax A.; Quinlan, Elizabeth M.

2015-01-01

In early postnatal development, naturally occurring cell death, dendritic outgrowth and synaptogenesis sculpt neuronal ensembles into functional neuronal circuits. Here we demonstrate that deletion of the extracellular proteinase MMP-9 affects each of these processes, resulting in maladapted neuronal circuitry. MMP-9 deletion increases the number of CA1 pyramidal neurons, but decreases dendritic length and complexity while dendritic spine density is unchanged. Parallel changes in neuronal morphology are observed in primary visual cortex, and persist into adulthood. Individual CA1 neurons in MMP-9−/− mice have enhanced input resistance and a significant increase in the frequency, but not amplitude, of miniature excitatory postsynaptic currents (mEPSCs). Additionally, deletion of MMP-9 significant increases spontaneous neuronal activity in awake MMP-9−/− mice and enhances response to acute challenge by the excitotoxin kainate. Thus MMP-9-dependent proteolysis regulates several aspects of circuit maturation to constrain excitability throughout life. PMID:26093382

Autism as a neurodevelopmental disorder affecting communication and learning in early childhood: prenatal origins, post-natal course and effective educational support.

PubMed

Trevarthen, C

2000-01-01

Colwyn Trevarthen, working on autism, discussed the importance of time, rhythm and temporal processing in brain function. The brains of new born infants show highly coherent and coordinated patterns of activity over time, and their rhythms are remarkably similar to those of adults. Since the cortex has not yet developed, this coordination must be subcortical in origin. The likely source is the emotional motor system. He noted that the cerebellum might regulate the intricate timing of the development and expression of emotional communication. He also pointed out that emotional and motivational factors have often been seriously neglected in psychology (largely owing to a misplaced focus on 'cognition' as some isolated entity) and emphasized the potential importance of empathetic support and music therapy in helping autistic children. Copyright 2000 Harcourt Publishers Ltd.

Effects of an overload of animal protein on the rat: brain DNA alterations and tissue morphological modifications during fetal and post-natal stage.

PubMed

Greco, A M; Sticchi, R; Boschi, G; Vetrani, A; Salvatore, G

1985-01-01

On account of many literature reports about the definite correlation between high animal protein intake and cardiovascular diseases, we have studied the effect of a hyperproteic purified diet (casein 40%, lactalbumin 20%) on fetal and post-natal (not further than 40th day) stage of the rat, when cell subdivision process is faster and therefore damage by nutritional imbalance is certainly more serious. Litters of rats were grouped according to mother's (either hyperproteic or common basic) and rat's (after lactation) diet. Brain DNA and histology of various organs were studied. Hyperproteic diet during fetal stage and lactation would inhibit brain cell subdivision since overall content of brain DNA would be decreased on autoptic finding. Structural changes were also shown in liver, heart, kidney and adrenal cortex, especially when hyperproteic diet was continued even after lactation.

Genetic Feedback Regulation of Frontal Cortical Neuronal Ensembles Through Activity-Dependent Arc Expression and Dopaminergic Input.

PubMed

Mastwal, Surjeet; Cao, Vania; Wang, Kuan Hong

2016-01-01

Mental functions involve coordinated activities of specific neuronal ensembles that are embedded in complex brain circuits. Aberrant neuronal ensemble dynamics is thought to form the neurobiological basis of mental disorders. A major challenge in mental health research is to identify these cellular ensembles and determine what molecular mechanisms constrain their emergence and consolidation during development and learning. Here, we provide a perspective based on recent studies that use activity-dependent gene Arc/Arg3.1 as a cellular marker to identify neuronal ensembles and a molecular probe to modulate circuit functions. These studies have demonstrated that the transcription of Arc is activated in selective groups of frontal cortical neurons in response to specific behavioral tasks. Arc expression regulates the persistent firing of individual neurons and predicts the consolidation of neuronal ensembles during repeated learning. Therefore, the Arc pathway represents a prototypical example of activity-dependent genetic feedback regulation of neuronal ensembles. The activation of this pathway in the frontal cortex starts during early postnatal development and requires dopaminergic (DA) input. Conversely, genetic disruption of Arc leads to a hypoactive mesofrontal dopamine circuit and its related cognitive deficit. This mutual interaction suggests an auto-regulatory mechanism to amplify the impact of neuromodulators and activity-regulated genes during postnatal development. Such a mechanism may contribute to the association of mutations in dopamine and Arc pathways with neurodevelopmental psychiatric disorders. As the mesofrontal dopamine circuit shows extensive activity-dependent developmental plasticity, activity-guided modulation of DA projections or Arc ensembles during development may help to repair circuit deficits related to neuropsychiatric disorders.

IGF-1 Restores Visual Cortex Plasticity in Adult Life by Reducing Local GABA Levels

PubMed Central

Maya-Vetencourt, José Fernando; Baroncelli, Laura; Viegi, Alessandro; Tiraboschi, Ettore; Castren, Eero; Cattaneo, Antonino; Maffei, Lamberto

2012-01-01

The central nervous system architecture is markedly modified by sensory experience during early life, but a decline of plasticity occurs with age. Recent studies have challenged this dogma providing evidence that both pharmacological treatments and paradigms based on the manipulation of environmental stimulation levels can be successfully employed as strategies for enhancing plasticity in the adult nervous system. Insulin-like growth factor 1 (IGF-1) is a peptide implicated in prenatal and postnatal phases of brain development such as neurogenesis, neuronal differentiation, synaptogenesis, and experience-dependent plasticity. Here, using the visual system as a paradigmatic model, we report that IGF-1 reactivates neural plasticity in the adult brain. Exogenous administration of IGF-1 in the adult visual cortex, indeed, restores the susceptibility of cortical neurons to monocular deprivation and promotes the recovery of normal visual functions in adult amblyopic animals. These effects were accompanied by a marked reduction of intracortical GABA levels. Moreover, we show that a transitory increase of IGF-1 expression is associated to the plasticity reinstatement induced by environmental enrichment (EE) and that blocking IGF-1 action by means of the IGF-1 receptor antagonist JB1 prevents EE effects on plasticity processes. PMID:22720172

Critical period for acoustic preference in mice

PubMed Central

Yang, Eun-Jin; Lin, Eric W.; Hensch, Takao K.

2012-01-01

Preference behaviors are often established during early life, but the underlying neural circuit mechanisms remain unknown. Adapting a unique nesting behavior assay, we confirmed a “critical period” for developing music preference in C57BL/6 mice. Early music exposure between postnatal days 15 and 24 reversed their innate bias for silent shelter, which typically could not be altered in adulthood. Instead, exposing adult mice treated acutely with valproic acid or carrying a targeted deletion of the Nogo receptor (NgR−/−) unmasked a strong plasticity of preference consistent with a reopening of the critical period as seen in other systems. Imaging of cFos expression revealed a prominent neuronal activation in response to the exposed music in the prelimbic and infralimbic medial prefrontal cortex only under conditions of open plasticity. Neither behavioral changes nor selective medial prefrontal cortex activation was observed in response to pure tone exposure, indicating a music-specific effect. Open-field center crossings were increased concomitant with shifts in music preference, suggesting a potential anxiolytic effect. Thus, music may offer both a unique window into the emotional state of mice and a potentially efficient assay for molecular “brakes” on critical period plasticity common to sensory and higher order brain areas. PMID:23045690

Critical period for acoustic preference in mice.

PubMed

Yang, Eun-Jin; Lin, Eric W; Hensch, Takao K

2012-10-16

Preference behaviors are often established during early life, but the underlying neural circuit mechanisms remain unknown. Adapting a unique nesting behavior assay, we confirmed a "critical period" for developing music preference in C57BL/6 mice. Early music exposure between postnatal days 15 and 24 reversed their innate bias for silent shelter, which typically could not be altered in adulthood. Instead, exposing adult mice treated acutely with valproic acid or carrying a targeted deletion of the Nogo receptor (NgR(-/-)) unmasked a strong plasticity of preference consistent with a reopening of the critical period as seen in other systems. Imaging of cFos expression revealed a prominent neuronal activation in response to the exposed music in the prelimbic and infralimbic medial prefrontal cortex only under conditions of open plasticity. Neither behavioral changes nor selective medial prefrontal cortex activation was observed in response to pure tone exposure, indicating a music-specific effect. Open-field center crossings were increased concomitant with shifts in music preference, suggesting a potential anxiolytic effect. Thus, music may offer both a unique window into the emotional state of mice and a potentially efficient assay for molecular "brakes" on critical period plasticity common to sensory and higher order brain areas.

Different MK-801 administration schedules induce mild to severe learning impairments in an operant conditioning task: role of buspirone and risperidone in ameliorating these cognitive deficits.

PubMed

Rapanelli, Maximiliano; Frick, Luciana Romina; Bernardez-Vidal, Micaela; Zanutto, Bonifacio Silvano

2013-11-15

Blockade of N-methyl-d-aspartate receptor (NMDA) by the noncompetitive NMDA receptor (NMDAR) antagonist MK-801 produces behavioral abnormalities and alterations in prefrontal cortex (PFC) functioning. Due to the critical role of the PFC in operant conditioning task learning, we evaluated the effects of acute, repeated postnatal injections of MK-801 (0.1mg/kg) on learning performance. We injected Long-Evans rats i.p. with MK-801 (0.1mg/kg) using three different administration schedules: injection 40 min before beginning the task (during) (n=12); injection twice daily for six consecutive days prior to beginning the experimental procedures (prior) (n=12); or twice daily subcutaneous injections from postnatal day 7 to 11 (postnatal) (n=12). Next, we orally administered risperidone (serotonin receptor 2A and dopamine receptor 2 antagonist, 1mg/kg) or buspirone (serotonin receptor 1A partial agonist, 10mg/kg) to animals treated with the MK-801 schedule described above. The postnatal and prior administration schedules produced severe learning deficits, whereas injection of MK-801 just before training sessions had only mild effects on acquisition of an operant conditioning. Risperidone was able to reverse the detrimental effect of MK-801 in the animals that were treated with MK-801 during and prior training sessions. In contrast, buspirone was only effective at mitigating the cognitive deficits induced by MK-801 when administered during the training procedures. The data demonstrates that NMDA antagonism disrupts basic mechanisms of learning in a simple PFC-mediated operant conditioning task, and that buspirone and risperidone failed to attenuate the learning deficits when NMDA neurotransmission was blocked in the early stages of the postnatal period. Copyright © 2013 Elsevier B.V. All rights reserved.

A functional requirement for astroglia in promoting blood vessel development in the early postnatal brain.

PubMed

Ma, Shang; Kwon, Hyo Jun; Huang, Zhen

2012-01-01

Astroglia are a major cell type in the brain and play a key role in many aspects of brain development and function. In the adult brain, astrocytes are known to intimately ensheath blood vessels and actively coordinate local neural activity and blood flow. During development of the neural retina, blood vessel growth follows a meshwork of astrocytic processes. Several genes have also been implicated in retinal astrocytes for regulating vessel development. This suggests a role of astrocytes in promoting angiogenesis throughout the central nervous system. To determine the roles that astrocytes may play during brain angiogenesis, we employ genetic approaches to inhibit astrogliogenesis during perinatal corticogenesis and examine its effects on brain vessel development. We find that conditional deletion from glial progenitors of orc3, a gene required for DNA replication, dramatically reduces glial progenitor cell number in the subventricular zone and astrocytes in the early postnatal cerebral cortex. This, in turn, results in severe reductions in both the density and branching frequency of cortical blood vessels. Consistent with a delayed growth but not regression of vessels, we find neither significant net decreases in vessel density between different stages after normalizing for cortical expansion nor obvious apoptosis of endothelial cells in these mutants. Furthermore, concomitant with loss of astroglial interactions, we find increased endothelial cell proliferation, enlarged vessel luminal size as well as enhanced cytoskeletal gene expression in pericytes, which suggests compensatory changes in vascular cells. Lastly, we find that blood vessel morphology in mutant cortices recovers substantially at later stages, following astrogliosis. These results thus implicate a functional requirement for astroglia in promoting blood vessel growth during brain development.

Early continuous white noise exposure alters l-alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptor subunit glutamate receptor 2 and gamma-aminobutyric acid type a receptor subunit beta3 protein expression in rat auditory cortex.

PubMed

Xu, Jinghong; Yu, Liping; Zhang, Jiping; Cai, Rui; Sun, Xinde

2010-02-15

Auditory experience during the postnatal critical period is essential for the normal maturation of auditory function. Previous studies have shown that rearing infant rat pups under conditions of continuous moderate-level noise delayed the emergence of adult-like topographic representational order and the refinement of response selectivity in the primary auditory cortex (A1) beyond normal developmental benchmarks and indefinitely blocked the closure of a brief, critical-period window. To gain insight into the molecular mechanisms of these physiological changes after noise rearing, we studied expression of the AMPA receptor subunit GluR2 and GABA(A) receptor subunit beta3 in the auditory cortex after noise rearing. Our results show that continuous moderate-level noise rearing during the early stages of development decreases the expression levels of GluR2 and GABA(A)beta3. Furthermore, noise rearing also induced a significant decrease in the level of GABA(A) receptors relative to AMPA receptors. However, in adult rats, noise rearing did not have significant effects on GluR2 and GABA(A)beta3 expression or the ratio between the two units. These changes could have a role in the cellular mechanisms involved in the delayed maturation of auditory receptive field structure and topographic organization of A1 after noise rearing. Copyright 2009 Wiley-Liss, Inc.

Perinatal methadone exposure affects dopamine, norepinephrine, and serotonin in the weanling rat.

PubMed

Robinson, S E; Maher, J R; Wallace, M J; Kunko, P M

1997-01-01

On gestational day 7 pregnant rats were implanted with osmotic minipumps containing either methadone hydrochloride (initial dose, 9 mg/kg/day) or sterile water. Their offspring were cross-fostered so that they were exposed to methadone prenatally and/or postnatally. On postnatal day 21, dopamine (DA), norepinephrine (NE), serotonin (5-HT), and their metabolites were analyzed. Perinatal methadone exposure disrupted dopaminergic, noradrenergic, and serotonergic activity in a brain region- and gender-specific fashion. The ratio of the DA metabolite 3,4-dihydroxyphenylacetic acid (DOPAC) to DA was reduced in the frontal cortex of males exposed to methadone postnatally. No effects of perinatal methadone exposure were observed on DA and DOPAC in the striatum. The ratio of 3-methoxy-4-hydroxyphenylglycol (MOPEG) to NE in the hippocampus was increased significantly in males exposed to methadone prenatally. Striatal and parietal cortical 5-hydroxyindoleacetic acid (5-HIAA), but not its ratio to 5-HT, was increased slightly in rats exposed to methadone postnatally. Although parietal cortical 5-HT, 5-HIAA, and 5-hydroxytryptophan were all affected by perinatal methadone exposure, the ratios of metabolite and precursor to 5-HT were not affected. Effects of methadone exposure appeared to depend upon the developmental stage at which exposure occurred and did not appear to result from the phenomenon of neonatal withdrawal. Changes in activity of these three neurotransmitter systems may contribute to the effect of perinatal methadone on the activity of other neurons, such as cholinergic neurons.

Long-term effects of adolescent exposure to bisphenol A on neuron and glia number in the rat prefrontal cortex: Differences between the sexes and cell type.

PubMed

Wise, Leslie M; Sadowski, Renee N; Kim, Taehyeon; Willing, Jari; Juraska, Janice M

2016-03-01

Bisphenol A (BPA), an endocrine disruptor used in a variety of consumer products, has been found to alter the number of neurons in multiple brain areas in rats following exposure in perinatal development. Both the number of neurons and glia also change in the medial prefrontal cortex (mPFC) during adolescence, and this process is known to be influenced by gonadal hormones which could be altered by BPA. In the current study, we examined Long-Evans male and female rats that were administered BPA (0, 4, 40, or 400μg/kg/day) during adolescent development (postnatal days 27-46). In adulthood (postnatal day 150), the number of neurons and glia in the mPFC were stereologically assessed in methylene blue/azure II stained sections. There were no changes in the number of neurons, but there was a significant dose by sex interaction in number of glia in the mPFC. Pairwise comparisons between controls and each dose showed a significant increase in the number of glia between 0 and 40μg/kg/day in females, and a significant decrease in the number of glia between 0 and 4μg/kg/day in males. In order to determine the type of glial cells that were changing in these groups in response to adolescent BPA administration, adjacent sections were labelled with S100β (astrocytes) and IBA-1 (microglia) in the mPFC of the groups that differed. The number of microglia was significantly higher in females exposed to 40μg/kg/day than controls and lower in males exposed to 4μg/kg/day than controls. There were no significant effects of adolescent exposure to BPA on the number of astrocytes in male or females. Thus, adolescent exposure to BPA produced long-term alterations in the number of microglia in the mPFC of rats, the functional implications of which need to be explored. Copyright © 2016 Elsevier Inc. All rights reserved.

Thyroid hormone modulates the development of cholinergic terminal fields in the rat forebrain: relation to nerve growth factor receptor.

PubMed

Oh, J D; Butcher, L L; Woolf, N J

1991-04-24

Hyperthyroidism, induced in rat pups by the daily intraperitoneal administration of 1 microgram/g body weight triiodothyronine, facilitated the development of ChAT fiber plexuses in brain regions innervated by basal forebrain cholinergic neurons, leading to an earlier and increased expression of cholinergic markers in those fibers in the cortex, hippocampus and amygdala. A similar enhancement was seen in the caudate-putamen complex. This histochemical profile was correlated with an accelerated appearance of ChAT-positive telencephalic puncta, as well as with a larger total number of cholinergic terminals expressed, which persisted throughout the eight postnatal week, the longest time examined in the present study. Hypothyroidism was produced in rat pups by adding 0.5% propylthiouracil to the dams' diet beginning the day after birth. This dietary manipulation resulted in the diminished expression of ChAT in forebrain fibers and terminals. Hypothyroid treatment also reduced the quantity of ChAT puncta present during postnatal weeks 2 and 3, and, from week 4 and continuing through week 6, the number of ChAT-positive terminals in the telencephalic regions examined was actually less than the amount extant during the former developmental epoch. Immunostaining for nerve growth factor receptor (NGF-R), which is associated almost exclusively with ChAT-positive somata and fibers in the basal forebrain, demonstrated a different time course of postnatal development. Forebrain fibers and terminals demonstrating NGF-R were maximally visualized 1 week postnatally, a time at which these same neuronal elements evinced minimal ChAT-like immunopositivity. Thereafter and correlated with increased immunoreactivity for ChAT, fine details of NGF-R stained fibers were observed less frequently. Although propylthiouracil administration decreased NGF-R immunodensity, no alteration in the development of that receptor was observed as a function of triiodothyronine treatment. Cholinergic terminals in the ventrobasal thalamus, which derive from ChAT-positive neurons in the pedunculopontine and laterodorsal tegmental nucleus, were unaffected by either hyperthyroid or hypothyroid conditions. These cells also do not demonstrate NGF-R. We conclude from these experiments (1) that cholinergic fiber plexuses eventually exhibiting ChAT positivity in the telencephalon demonstrate NGF-R prior to the cholinergic synthetic enzyme, (2) that susceptibility to thyroid hormone manipulations may involve sensitivity to NGF, at least in some forebrain cholinergic systems and (3) that the effects of thyroid hormone imbalances on brain cholinergic neurons are regionally selective.

Altered cortical expression of GABA-related genes in schizophrenia: illness progression vs developmental disturbance.

PubMed

Hoftman, Gil D; Volk, David W; Bazmi, H Holly; Li, Siyu; Sampson, Allan R; Lewis, David A

2015-01-01

Schizophrenia is a neurodevelopmental disorder with altered expression of GABA-related genes in the prefrontal cortex (PFC). However, whether these gene expression abnormalities reflect disturbances in postnatal developmental processes before clinical onset or arise as a consequence of clinical illness remains unclear. Expression levels for 7 GABA-related transcripts (vesicular GABA transporter [vGAT], GABA membrane transporter [GAT1], GABAA receptor subunit α1 [GABRA1] [novel in human and monkey cohorts], glutamic acid decarboxylase 67 [GAD67], parvalbumin, calretinin, and somatostatin [previously reported in human cohort, but not in monkey cohort]) were quantified in the PFC from 42 matched pairs of schizophrenia and comparison subjects and from 49 rhesus monkeys ranging in age from 1 week postnatal to adulthood. Levels of vGAT and GABRA1, but not of GAT1, messenger RNAs (mRNAs) were lower in the PFC of the schizophrenia subjects. As previously reported, levels of GAD67, parvalbumin, and somatostatin, but not of calretinin, mRNAs were also lower in these subjects. Neither illness duration nor age accounted for the levels of the transcripts with altered expression in schizophrenia. In monkey PFC, developmental changes in expression levels of many of these transcripts were in the opposite direction of the changes observed in schizophrenia. For example, mRNA levels for vGAT, GABRA1, GAD67, and parvalbumin all increased with age. Together with published reports, these findings support the interpretation that the altered expression of GABA-related transcripts in schizophrenia reflects a blunting of normal postnatal development changes, but they cannot exclude a decline during the early stages of clinical illness. © The Author 2013. Published by Oxford University Press on behalf of the Maryland Psychiatric Research Center. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Prevention of cataracts in pink-eyed RCS rats by dark rearing.

PubMed

O'Keefe, T L; Hess, H H; Zigler, J S; Kuwabara, T; Knapka, J J

1990-11-01

Royal College of Surgeons rats have hereditary retinal degeneration and associated posterior subcapsular opacities (PSO) of the lens, detectable by slitlamp at 7-8 postnatal weeks in both pink- and black-eyed rats. The retinal degeneration is intensified by light, especially in pink-eyed rats. A fourth of pink-eyed rats developed mature cataracts by 9-12 months of age, but black-eyed rats whose retinas are protected from light by pigmented irises and pigment epithelium rarely have mature cataracts (3% or less), indicating light may be a factor in cataractogenesis. Prior work had shown that dark rearing reduced the rate of retinal degeneration in pink- but not black-eyed rats, but cataracts were not studied. In the present work, pregnant pink-eyed females were placed in a darkroom 1 week before parturition. Pups were removed over intervals at 20-85 postnatal days for: (a) microscopic study of fresh lenses and of fixed, stained retina and lens, and (b) counts of cells mm-2 of the web-like vitreous cortex after it had been dissected free. The macrophage-like cells are a quantitative index of immune reaction to retinal damage. At 50-53 postnatal days, in pink-eyed cyclic light reared RCS, the mean number of macrophages was 4.6-fold that in congenic controls, but in those that were dark reared it was only 1.4-fold. This was less than the increase in cyclic light reared black-eyed RCS (2.3-fold that in congenic black-eyed controls). Total absence of light reduced retinal degeneration and the number of macrophages, and prevented PSO detectable microscopically.(ABSTRACT TRUNCATED AT 250 WORDS)

The perinatal effects of maternal caffeine intake on fetal and neonatal brain levels of testosterone, estradiol, and dihydrotestosterone in rats.

PubMed

Karaismailoglu, S; Tuncer, M; Bayrak, S; Erdogan, G; Ergun, E L; Erdem, A

2017-08-01

Testosterone, estradiol, and dihydrotestosterone are the main sex steroid hormones responsible for the organization and sexual differentiation of brain structures during early development. The hypothalamo-pituitary-adrenocortical axis, adrenal cells, and gonads play a key role in the production of sex steroids and express adenosine receptors. Caffeine is a non-selective adenosine antagonist; therefore, it can modulate metabolic pathways in these tissues. Besides, the proportion of pregnant women that consume caffeine is ∼60%. That is why the relationship between maternal caffeine consumption and fetal development is important. Therefore, we aimed to investigate this modulatory effect of maternal caffeine consumption on sex steroids in the fetal and neonatal brain tissues. Pregnant rats were treated with a low (0.3 g/L) or high (0.8 g/L) dose of caffeine in their drinking water during pregnancy and lactation. The testosterone, estradiol, and dihydrotestosterone levels in the frontal cortex and hypothalamus were measured using radioimmunoassay at embryonic day 19 (E19), birth (PN0), and postnatal day 4 (PN4). The administration of low-dose caffeine increased the body weight in PN4 male and female rats and anogenital index in PN4 males. The administration of high-dose caffeine decreased the adrenal weight in E19 male rats and increased testosterone levels in the frontal cortex of E19 female rats and the hypothalamus of PN0 male rats. Maternal caffeine intake during pregnancy affects sex steroid levels in the frontal cortex and hypothalamus of the offspring. This concentration changes of the sex steroids in the brain may influence behavioral and neuroendocrine functions at some point in adult life.

Developmental Exposure to Cocaine Dynamically Dysregulates Cortical Arc/Arg3.1 Modulation in Response to a Challenge.

PubMed

Caffino, Lucia; Giannotti, Giuseppe; Mottarlini, Francesca; Racagni, Giorgio; Fumagalli, Fabio

2017-02-01

During adolescence, the medial prefrontal cortex (mPFC) is still developing. We have previously shown that developmental cocaine exposure alters mPFC's ability to cope with challenging events. In this manuscript, we exposed rats developmentally treated with cocaine to a novelty task and analyzed the molecular changes of mPFC. Rats were exposed to cocaine from post-natal day (PND) 28 to PND 42 and sacrificed at PND 43, immediately after the novel object recognition (NOR) test. Cocaine-treated rats spent more time exploring the novel object than saline-treated counterparts, suggesting an increased response to novelty. The messenger RNA (mRNA) and protein levels of the immediate early gene Arc/Arg3.1 were reduced in both infralimbic (IL) and prelimbic (PL) cortices highlighting a baseline reduction of mPFC neuronal activity as a consequence of developmental exposure to cocaine. Intriguingly, significant molecular changes were observed in the IL, but not PL, cortex in response to the combination of cocaine exposure and test such as a marked upregulation of both Arc/Arg3.1 mRNA and protein levels only in cocaine-treated rats. As for proteins, such increase was observed only in the post-synaptic density and not in the whole homogenate, suggesting psychostimulant-induced changes in trafficking of Arc/Arg3.1 or an increased local translation. Notably, the same profile of Arc/Arg3.1 was observed for post-synaptic density (PSD)-95 leading to the possibility that Arc/Arg3.1 and PSD-95 bridge together to promote aberrant synaptic connectivity in IL cortex following repeated exposure to cocaine during brain development.

Zic deficiency in the cortical marginal zone and meninges results in cortical lamination defects resembling those in type II lissencephaly.

PubMed

Inoue, Takashi; Ogawa, Masaharu; Mikoshiba, Katsuhiko; Aruga, Jun

2008-04-30

The formation of the highly organized cortical structure depends on the production and correct placement of the appropriate number and types of neurons. The Zic family of zinc-finger transcription factors plays essential roles in regulating the proliferation and differentiation of neuronal progenitors in the medial forebrain and the cerebellum. Examination of the expression of Zic genes demonstrated that Zic1, Zic2, and Zic3 were expressed by the progenitor cells in the septum and cortical hem, the sites of generation of the Cajal-Retzius (CR) cells. Immunohistochemical studies have revealed that Zic proteins were abundantly expressed in the meningeal cells and that the majority of the CR cells distributed in the medial and dorsal cortex also expressed Zic proteins in the mid-late embryonic and postnatal cortical marginal zones. During embryonic cortical development, Zic1/Zic3 double-mutant and hypomorphic Zic2 mutant mice showed a reduction in the number of CR cells in the rostral cortex, whereas the cell number remained unaffected in the caudal cortex. These mutants also showed mislocalization of the CR cells and cortical lamination defects, resembling the changes noted in type II (cobblestone) lissencephaly, throughout the brain. In the Zic1/3 mutant, reduced proliferation of the meningeal cells was observed before the thinner and disrupted organization of the pial basement membrane (BM) with reduced expression of the BM components and the meningeal cell-derived secretory factor. These defects correlated with the changes in the end feet morphology of the radial glial cells. These findings indicate that the Zic genes play critical roles in cortical development through regulating the proliferation of meningeal cells and the pial BM assembly.

Astrocytes refine cortical connectivity at dendritic spines

PubMed Central

Risher, W Christopher; Patel, Sagar; Kim, Il Hwan; Uezu, Akiyoshi; Bhagat, Srishti; Wilton, Daniel K; Pilaz, Louis-Jan; Singh Alvarado, Jonnathan; Calhan, Osman Y; Silver, Debra L; Stevens, Beth; Calakos, Nicole; Soderling, Scott H; Eroglu, Cagla

2014-01-01

During cortical synaptic development, thalamic axons must establish synaptic connections despite the presence of the more abundant intracortical projections. How thalamocortical synapses are formed and maintained in this competitive environment is unknown. Here, we show that astrocyte-secreted protein hevin is required for normal thalamocortical synaptic connectivity in the mouse cortex. Absence of hevin results in a profound, long-lasting reduction in thalamocortical synapses accompanied by a transient increase in intracortical excitatory connections. Three-dimensional reconstructions of cortical neurons from serial section electron microscopy (ssEM) revealed that, during early postnatal development, dendritic spines often receive multiple excitatory inputs. Immuno-EM and confocal analyses revealed that majority of the spines with multiple excitatory contacts (SMECs) receive simultaneous thalamic and cortical inputs. Proportion of SMECs diminishes as the brain develops, but SMECs remain abundant in Hevin-null mice. These findings reveal that, through secretion of hevin, astrocytes control an important developmental synaptic refinement process at dendritic spines. DOI: http://dx.doi.org/10.7554/eLife.04047.001 PMID:25517933

Stress-Induced Transcriptional Regulation in the Developing Rat Brain Involves Increased Cyclic Adenosine 3′,5′-Monophosphate-Regulatory Element Binding Activity

PubMed Central

Hatalski, Carolyn G.; Baram, Tallie Z.

2012-01-01

The cAMP-regulatory element (CRE) binding protein (CREB) functions as a trans-acting regulator of genes containing the CRE sequence in their promoter. These include a number of critical genes, such as CRF, involved in the hypothalamic response to stressful stimuli in the adult. The ability of the developing rat (during the first 2 postnatal weeks) to mount the full complement of this stress response has been questioned. We have previously demonstrated the stress-induced up-regulation of the transcription of hypothalamic CRF during the second postnatal week in the rat. The focus of the current study was to explore the mechanism of transcriptional regulation in response to stress through the physiological induction of transcriptional trans-activators that bind to the CRE in the developing rat brain. CRE-binding activity was detected via gel shift analysis in extracts from both the hypothalamus and the cerebral cortex of the developing rat. CREB was identified in these extracts by Western blot analysis and was shown to be the major contributor to the CRE-binding activity by gel shift analysis with two specific antibodies directed against CREB. After acute hypothermic stress, the abundance of CRE-binding activity (but not of total immunoreactive CREB), increased in hypothalamic extracts. This enhanced CRE-binding activity was blocked by an antiserum directed against CREB and was accompanied by an apparent increase in CREB phosphorylation. These results indicate that posttranslational enhancement of CRE-binding activity is likely to constitute an important mechanism for up-regulation of genes possessing the CRE sequence in the developing rat hypothalamus by adverse external signals. PMID:9415405

Synaptogenesis in visual cortex of normal and preterm monkeys: evidence for intrinsic regulation of synaptic overproduction.

PubMed Central

Bourgeois, J P; Jastreboff, P J; Rakic, P

1989-01-01

We used quantitative electron microscopy to determine the effect of precocious visual experience on the time course, magnitude, and pattern of perinatal synaptic overproduction in the primary visual cortex of the rhesus monkey. Fetuses were delivered by caesarean section 3 weeks before term, exposed to normal light intensity and day/night cycles, and killed within the first postnatal month, together with age-matched controls that were delivered at term. We found that premature visual stimulation does not affect the rate of synaptic accretion and overproduction. Both of these processes proceed in relation to the time of conception rather than to the time of delivery. In contrast, the size, type, and laminar distribution of synapses were significantly different between preterm and control infants. The changes and differences in these parameters correlate with the duration of visual stimulation and become less pronounced with age. If visual experience in infancy influences the maturation of the visual cortex, it must do so predominantly by strengthening, modifying, and/or eliminating synapses that have already been formed, rather than by regulating the rate of synapse production. Images PMID:2726773

Magnetic resonance spectroscopic analysis of neurometabolite changes in the developing rat brain at 7T.

PubMed

Ramu, Jaivijay; Konak, Tetyana; Liachenko, Serguei

2016-11-15

We utilized proton magnetic resonance spectroscopy to evaluate the metabolic profile of the hippocampus and anterior cingulate cortex of the developing rat brain from postnatal days 14-70. Measured metabolite concentrations were modeled using linear, exponential, or logarithmic functions and the time point at which the data reached plateau (i.e. when the portion of the data could be fit to horizontal line) was estimated and was interpreted as the time when the brain has reached maturity with respect to that metabolite. N-acetyl-aspartate and myo-inositol increased within the observed period. Gluthathione did not vary significantly, while taurine decreased initially and then stabilized. Phosphocreatine and total creatine had a tendency to increase towards the end of the experiment. Some differences between our data and the published literature were observed in the concentrations and dynamics of phosphocreatine, myo-inositol, and GABA in the hippocampus and creatine, GABA, glutamine, choline and N-acetyl-aspartate in the cortex. Such differences may be attributed to experimental conditions, analysis approaches and animal species. The latter is supported by differences between in-house rat colony and rats from Charles River Labs. Spectroscopy provides a valuable tool for non-invasive brain neurochemical profiling for use in developmental neurobiology research. Special attention needs to be paid to important sources of variation like animal strain and commercial source. Published by Elsevier B.V.

Neurobehavioral assessment of maternal odor in developing rat pups: implications for social buffering.

PubMed

Al Aïn, Syrina; Perry, Rosemarie E; Nuñez, Bestina; Kayser, Kassandra; Hochman, Chase; Brehman, Elizabeth; LaComb, Miranda; Wilson, Donald A; Sullivan, Regina M

2017-02-01

Social support can attenuate the behavioral and stress hormone response to threat, a phenomenon called social buffering. The mother's social buffering of the infant is one of the more robust examples; yet we understand little about the neurobiology. Using a rodent model, we explore the neurobiology of social buffering by assessing neural processing of the maternal odor, a major cue controlling social buffering in rat pups. We used pups before (postnatal day (PN) 7) and after (PN14, PN23) the functional emergence of social buffering. Pups were injected with 14 C 2-deoxyglucose (2-DG) and presented with the maternal odor, a control preferred odor incapable of social buffering (acetophenone), or no odor. Brains were removed, processed for autoradiography and brain areas identified as important in adult social buffering were assessed, including the amygdala basolateral complex (Basolateral Amygdala [BLA]), medial prefrontal cortex (mPFC), and anterior cingulate cortex (ACC). Results suggest dramatic changes in the processing of maternal odor. PN7 pups show mPFC and ACC activation, although PN14 pups showed no activation of the mPFC, ACC, or BLA. All brain areas assessed were recruited by PN23. Additional analysis suggests substantial changes in functional connectivity across development. Together, these results imply complex nonlinear transitions in the neurobiology of social buffering in early life that may provide insight into the changing role of the mother in supporting social buffering.

Frontal Cortex Transcriptome Analysis of Mice Exposed to Electronic Cigarettes During Early Life Stages

PubMed Central

Lauterstein, Dana E.; Tijerina, Pamella B.; Corbett, Kevin; Akgol Oksuz, Betul; Shen, Steven S.; Gordon, Terry; Klein, Catherine B.; Zelikoff, Judith T.

2016-01-01

Electronic cigarettes (e-cigarettes), battery-powered devices containing nicotine, glycerin, propylene glycol, flavorings, and other substances, are increasing in popularity. They pose a potential threat to the developing brain, as nicotine is a known neurotoxicant. We hypothesized that exposure to e-cigarettes during early life stages induce changes in central nervous system (CNS) transcriptome associated with adverse neurobiological outcomes and long-term disease states. To test the hypothesis, pregnant C57BL/6 mice were exposed daily (via whole body inhalation) throughout gestation (3 h/day; 5 days/week) to aerosols produced from e-cigarettes either with nicotine (13–16 mg/mL) or without nicotine; following birth, pups and dams were exposed together to e-cigarette aerosols throughout lactation beginning at postnatal day (PND) 4–6 and using the same exposure conditions employed during gestational exposure. Following exposure, frontal cortex recovered from ~one-month-old male and female offspring were excised and analyzed for gene expression by RNA Sequencing (RNA-Seq). Comparisons between the treatment groups revealed that e-cigarette constituents other than nicotine might be partly responsible for the observed biological effects. Transcriptome alterations in both offspring sexes and treatment groups were all significantly associated with downstream adverse neurobiological outcomes. Results from this study demonstrate that e-cigarette exposure during early life alters CNS development potentially leading to chronic neuropathology. PMID:27077873

Disruption of behavior and brain metabolism in artificially reared rats.

PubMed

Aguirre-Benítez, Elsa L; Porras, Mercedes G; Parra, Leticia; González-Ríos, Jacquelina; Garduño-Torres, Dafne F; Albores-García, Damaris; Avendaño, Arturo; Ávila-Rodríguez, Miguel A; Melo, Angel I; Jiménez-Estrada, Ismael; Mendoza-Garrido, Ma Eugenia; Toriz, César; Diaz, Daniel; Ibarra-Coronado, Elizabeth; Mendoza-Ángeles, Karina; Hernández-Falcón, Jesús

2017-12-01

Early adverse life stress has been associated to behavioral disorders that can manifest as inappropriate or aggressive responses to social challenges. In this study, we analyzed the effects of artificial rearing on the open field and burial behavioral tests and on GFAP, c-Fos immunoreactivity, and glucose metabolism measured in anxiety-related brain areas. Artificial rearing of male rats was performed by supplying artificial milk through a cheek cannula and tactile stimulation, mimicking the mother's licking to rat pups from the fourth postnatal day until weaning. Tactile stimulation was applied twice a day, at morning and at night, by means of a camel brush on the rat anogenital area. As compared to mother reared rats, greater aggressiveness, and boldness, stereotyped behavior (burial conduct) was observed in artificially reared rats which occurred in parallel to a reduction of GFAP immunoreactivity in somatosensory cortex, c-Fos immunoreactivity at the amygdala and primary somatosensory cortex, and lower metabolism in amygdala (as measured by 2-deoxi-2-[ 18 fluoro]-d-glucose uptake, assessed by microPET imaging). These results could suggest that tactile and/or chemical stimuli from the mother and littermates carry relevant information for the proper development of the central nervous system, particularly in brain areas involved with emotions and social relationships of the rat. © 2017 Wiley Periodicals, Inc. Develop Neurobiol 77: 1413-1429, 2017. © 2017 Wiley Periodicals, Inc.

Frontal Cortex Transcriptome Analysis of Mice Exposed to Electronic Cigarettes During Early Life Stages.

PubMed

Lauterstein, Dana E; Tijerina, Pamella B; Corbett, Kevin; Akgol Oksuz, Betul; Shen, Steven S; Gordon, Terry; Klein, Catherine B; Zelikoff, Judith T

2016-04-12

Electronic cigarettes (e-cigarettes), battery-powered devices containing nicotine, glycerin, propylene glycol, flavorings, and other substances, are increasing in popularity. They pose a potential threat to the developing brain, as nicotine is a known neurotoxicant. We hypothesized that exposure to e-cigarettes during early life stages induce changes in central nervous system (CNS) transcriptome associated with adverse neurobiological outcomes and long-term disease states. To test the hypothesis, pregnant C57BL/6 mice were exposed daily (via whole body inhalation) throughout gestation (3 h/day; 5 days/week) to aerosols produced from e-cigarettes either with nicotine (13-16 mg/mL) or without nicotine; following birth, pups and dams were exposed together to e-cigarette aerosols throughout lactation beginning at postnatal day (PND) 4-6 and using the same exposure conditions employed during gestational exposure. Following exposure, frontal cortex recovered from ~one-month-old male and female offspring were excised and analyzed for gene expression by RNA Sequencing (RNA-Seq). Comparisons between the treatment groups revealed that e-cigarette constituents other than nicotine might be partly responsible for the observed biological effects. Transcriptome alterations in both offspring sexes and treatment groups were all significantly associated with downstream adverse neurobiological outcomes. Results from this study demonstrate that e-cigarette exposure during early life alters CNS development potentially leading to chronic neuropathology.

Intra- and Interhemispheric Propagation of Electrophysiological Synchronous Activity and Its Modulation by Serotonin in the Cingulate Cortex of Juvenile Mice

PubMed Central

Rovira, Víctor; Geijo-Barrientos, Emilio

2016-01-01

Disinhibition of the cortex (e.g., by GABA -receptor blockade) generates synchronous and oscillatory electrophysiological activity that propagates along the cortex. We have studied, in brain slices of the cingulate cortex of mice (postnatal age 14–20 days), the propagation along layer 2/3 as well as the interhemispheric propagation through the corpus callosum of synchronous discharges recorded extracellularly and evoked in the presence of 10 μM bicuculline by electrical stimulation of layer 1. The latency of the responses obtained at the same distance from the stimulus electrode was longer in anterior cingulate cortex (ACC: 39.53 ± 2.83 ms, n = 7) than in retrosplenial cortex slices (RSC: 21.99 ± 2.75 ms, n = 5; p<0.05), which is equivalent to a lower propagation velocity in the dorso-ventral direction in ACC than in RSC slices (43.0 mm/s vs 72.9 mm/s). We studied the modulation of this propagation by serotonin. Serotonin significantly increased the latency of the intracortical synchronous discharges (18.9% in the ipsilateral hemisphere and 40.2% in the contralateral hemisphere), and also increased the interhemispheric propagation time by 86.4%. These actions of serotonin were mimicked by the activation of either 5-HT1B or 5-HT2A receptors, but not by the activation of the 5-HT1A subtype. These findings provide further knowledge about the propagation of synchronic electrical activity in the cerebral cortex, including its modulation by serotonin, and suggest the presence of deep differences between the ACC and RSC in the structure of the local cortical microcircuits underlying the propagation of synchronous discharges. PMID:26930051

Individual Variations in Maternal Care Early in Life Correlate with Later Life Decision-Making and c-Fos Expression in Prefrontal Subregions of Rats

PubMed Central

van Hasselt, Felisa N.; de Visser, Leonie; Tieskens, Jacintha M.; Cornelisse, Sandra; Baars, Annemarie M.; Lavrijsen, Marla; Krugers, Harm J.; van den Bos, Ruud; Joëls, Marian

2012-01-01

Early life adversity affects hypothalamus-pituitary-adrenal axis activity, alters cognitive functioning and in humans is thought to increase the vulnerability to psychopathology–e.g. depression, anxiety and schizophrenia- later in life. Here we investigated whether subtle natural variations among individual rat pups in the amount of maternal care received, i.e. differences in the amount of licking and grooming (LG), correlate with anxiety and prefrontal cortex-dependent behavior in young adulthood. Therefore, we examined the correlation between LG received during the first postnatal week and later behavior in the elevated plus maze and in decision-making processes using a rodent version of the Iowa Gambling Task (rIGT). In our cohort of male and female animals a high degree of LG correlated with less anxiety in the elevated plus maze and more advantageous choices during the last 10 trials of the rIGT. In tissue collected 2 hrs after completion of the task, the correlation between LG and c-fos expression (a marker of neuronal activity) was established in structures important for IGT performance. Negative correlations existed between rIGT performance and c-fos expression in the lateral orbitofrontal cortex, prelimbic cortex, infralimbic cortex and insular cortex. The insular cortex correlations between c-fos expression and decision-making performance depended on LG background; this was also true for the lateral orbitofrontal cortex in female rats. Dendritic complexity of insular or infralimbic pyramidal neurons did not or weakly correlate with LG background. We conclude that natural variations in maternal care received by pups may significantly contribute to later-life decision-making and activity of underlying brain structures. PMID:22693577

Exposure to a mildly aversive early life experience leads to prefrontal cortex deficits in the rat.

PubMed

Stamatakis, Antonios; Manatos, Vasileios; Kalpachidou, Theodora; Stylianopoulou, Fotini

2016-11-01

Aversive early life experiences in humans have been shown to result in deficits in the function of the prefrontal cortex (PFC). In an effort to elucidate possible neurobiological mechanisms involved, we investigated in rats, the effects of a mildly aversive early experience on PFC structure and function. The early experience involved exposure of rat pups during postnatal days (PND) 10-13 to a T-maze in which they search for their mother, but upon finding her are prohibited contact with her, thus being denied the expected reward (DER). We found that the DER experience resulted in adulthood in impaired PFC function, as assessed by two PFC-dependent behavioral tests [attention set-shifting task (ASST) and fear extinction]. In the ASST, DER animals showed deficits specifically in the intra-dimensional reversal shifts and a lower activation-as determined by c-Fos immunohistochemistry-of the medial orbital cortex (MO), a PFC subregion involved in this aspect of the task. Furthermore, the DER experience resulted in decreased glutamatergic neuron and dendritic spine density in the MO and infralimbic cortex (IL) in the adult brain. The decreased neuronal density was detected as early as PND12 and was accompanied by increased micro- and astroglia-density in the MO/IL.

Neurochemistry in shiverer mouse depicted on MR spectroscopy.

PubMed

Takanashi, Jun-ichi; Nitta, Nobuhiro; Iwasaki, Nobuaki; Saito, Shigeyoshi; Tanaka, Ryuta; Barkovich, A James; Aoki, Ichio

2014-06-01

To evaluate the neurochemical changes associated with hypomyelination, especially to clarify whether increased total N-acetylaspartate (tNAA) with decreased choline (Cho) observed in the thalamus of msd mice with the plp1 mutation is a common finding for hypomyelinating disorders. We performed magnetic resonance imaging (MRI) and proton MR spectroscopy ((1) H-MRS) of the thalamus and cortex of postnatal 12-week shiverer mice devoid of myelin basic protein (mbp), heterozygous and wild-type mice with a 7.0T magnet. Luxol Fast Blue staining and immunohistochemical analysis with anti-Mbp, Gfap, Olig2, and NeuN antibodies were also performed. In the thalamus, decreased Cho and normal tNAA were observed in shiverer mice. In the cortex, tNAA, Cho, and glutamate were decreased in shiverer mice. Histological and immunohistochemical analysis of shiverer mice brains revealed hypomyelination in the thalamus, white matter, and cortex; astrogliosis and an increased number of total oligodendrocytes in the white matter; and a decreased number of neurons in the cortex. The reduction of Cho on (1) H-MRS might be a common marker for hypomyelinating disorders. A normal tNAA level in the thalamus of shiverer mice might be explained by the presence of mature oligodendrocytes, which enable neuron-to-oligodendrocyte NAA transport or NAA catabolism. Copyright © 2013 Wiley Periodicals, Inc.

Intergenerational impact of paternal lifetime exposures to both folic acid deficiency and supplementation on reproductive outcomes and imprinted gene methylation.

PubMed

Ly, Lundi; Chan, Donovan; Aarabi, Mahmoud; Landry, Mylène; Behan, Nathalie A; MacFarlane, Amanda J; Trasler, Jacquetta

2017-07-01

Do paternal exposures to folic acid deficient (FD), and/or folic acid supplemented (FS) diets, throughout germ cell development adversely affect male germ cells and consequently offspring health outcomes? Male mice exposed over their lifetimes to both FD and FS diets showed decreased sperm counts and altered imprinted gene methylation with evidence of transmission of adverse effects to the offspring, including increased postnatal-preweaning mortality and variability in imprinted gene methylation. There is increasing evidence that disruptions in male germ cell epigenetic reprogramming are associated with offspring abnormalities and intergenerational disease. The fetal period is the critical time of DNA methylation pattern acquisition for developing male germ cells and an adequate supply of methyl donors is required. In addition, DNA methylation patterns continue to be remodeled during postnatal spermatogenesis. Previous studies have shown that lifetime (prenatal and postnatal) folic acid deficiency can alter the sperm epigenome and increase the incidence of fetal morphological abnormalities. Female BALB/c mice (F0) were placed on one of four amino-acid defined diets for 4 weeks before pregnancy and throughout pregnancy and lactation: folic acid control (Ctrl; 2 mg/kg), 7-fold folic acid deficient (7FD; 0.3 mg/kg), 10-fold high FS (10FS, 20 mg/kg) or 20-fold high FS (20FS, 40 mg/kg) diets. F1 males were weaned to their respective prenatal diets to allow for diet exposure during all windows of germline epigenetic reprogramming: the erasure, re-establishment and maintenance phases. F0 females were mated with chow-fed males to produce F1 litters whose germ cells were exposed to the diets throughout embryonic development. F1 males were subsequently mated with chow-fed female mice. Two F2 litters, unexposed to the experimental diets, were generated from each F1 male; one litter was collected at embryonic day (E)18.5 and one delivered and followed postnatally. DNA methylation at a global level and at the differentially methylated regions of imprinted genes (H19, Imprinted Maternally Expressed Transcript (Non-Protein Coding)-H19, Small Nuclear Ribonucleoprotein Polypeptide N-Snrpn, KCNQ1 Opposite Strand/Antisense Transcript 1 (Non-Protein Coding)-Kcnq1ot1, Paternally Expressed Gene 1-Peg1 and Paternally Expressed Gene 3-Peg3) was assessed by luminometric methylation analysis and bisulfite pyrosequencing, respectively, in F1 sperm, F2 E18.5 placenta and F2 E18.5 brain cortex. F1 males exhibited lower sperm counts following lifetime exposure to both folic acid deficiency and the highest dose of folic acid supplementation (20FS), (both P < 0.05). Post-implantation losses were increased amongst F2 E18.5 day litters from 20FS exposed F1 males (P < 0.05). F2 litters derived from both 7FD and 20FS exposed F1 males had significantly higher postnatal-preweaning pup death (both P < 0.05). Sperm from 10FS exposed males had increased variance in methylation across imprinted gene H19, P < 0.05; increased variance at a few sites within H19 was also found for the 7FD and 20FS groups (P < 0.05). While the 20FS diet resulted in inter-individual alterations in methylation across the imprinted genes Snrpn and Peg3 in F2 E18.5 placenta, ≥50% of individual sites tested in Peg1 and/or Peg3 were affected in the 7FD and 10FS groups. Inter-individual alterations in Peg1 methylation were found in F2 E18.5 day 10FS group brain cortex (P < 0.05). Not applicable. The cause of the increase in postnatal-preweaning mortality was not investigated post-mortem. Further studies are required to understand the mechanisms underlying the adverse effects of folic acid deficiency and supplementation on developing male germ cells. Genome-wide DNA and histone methylome studies as well as gene expression studies are required to better understand the links between folic acid exposures, an altered germ cell epigenome and offspring outcomes. The findings of this study provide further support for paternally transmitted environmental effects. The results indicate that both folic acid deficiency and high dose supplementation can be detrimental to germ cell development and reproductive fitness, in part by altering DNA methylation in sperm. This study was supported by a grant to J.M.T. from the Canadian Institutes of Health Research (CIHR #89944). The authors declare they have no conflicts of interest. © The Author 2017. Published by Oxford University Press on behalf of the European Society of Human Reproduction and Embryology. All rights reserved. For Permissions, please email: journals.permissions@oup.com

[Thick and thin zones of the neurocranium, impressiones gyrorum and foramina parietalia in children and adults (author's transl)].

PubMed

Lang, J; Brückner, B

1981-01-01

At 102 skulls from adults and 67 skulls from children we have investigated 1) The postnatal changes of the thickness from basal parts of the Fossae craniales ant., med. et post. 2) The postnatal thickening and lateral shifting of the Processus clinoideus anterior. 3) The postnatal development at the superior side of the Canalis opticus. 4) Between the Os sphenoidale Clivus angle from newborn age to 17 years of life at 67 skulls. 5) The postnatal changes of the lateral angle at the Pars petrosa and its right-left-differences. 6) The postnatal thickening of the Calvaria (Squama frontalis - Tuber frontale, Os parietale - Tuber parietale). 7) The development, size and position of the Foramina parietalia. 8) The postnatal development of the Protuberantiae gyrorum and Sulci meningei.

Effects of prenatal and postnatal maternal emotional stress on toddlers' cognitive and temperamental development.

PubMed

Lin, Yanfen; Xu, Jian; Huang, Jun; Jia, Yinan; Zhang, Jinsong; Yan, Chonghuai; Zhang, Jun

2017-01-01

Maternal stress is associated with impairments in the neurodevelopment of offspring; however, the effects of the timing of exposure to maternal stress on a child's neurodevelopment are unclear. In 2010, we studied 225 mother-child pairs in Shanghai, recruiting mothers in mid-to-late pregnancy and monitoring offspring from birth until 30 months of age. Maternal stress was assessed prenatally (at 28-36 weeks of gestation) and postnatally (at 24-30 months postpartum) using the Symptom-Checklist-90-Revised Scale (SCL-90-R) and Life-Event-Stress Scale to evaluate mothers' emotional stress and life event stress levels, respectively. Children's cognition and temperament were assessed at 24-30 months of age using the Gesell Development Scale and Toddler Temperament Scale, respectively. Multi-variable linear regression models were used to associate prenatal and postnatal stress with child cognitive and temperamental development. Maternal prenatal and postnatal Global Severity Index (GSI) of SCL-90-R were moderately correlated (ICC r=0.30, P<0.001). After adjusting for relevant covariates, the increase in prenatal GSI was associated with decreases in toddlers' gross motor, fine motor, adaptive and social behavior development independently of postnatal GSI, while the increase in postnatal GSI was associated with changes in multiple temperament dimensions independently of prenatal GSI. The effects of prenatal and postnatal depression scores of SCL-90-R were similar to those of GSI. Relatively small sample size. Compared with postnatal exposure, children's cognitive development may be more susceptible to prenatal exposure to maternal emotional stress, whereas temperamental development may be more affected by postnatal exposure to maternal emotional stress compared with prenatal exposure. Copyright © 2016 Elsevier B.V. All rights reserved.

Unilateral nasal obstruction affects motor representation development within the face primary motor cortex in growing rats.

PubMed

Abe, Yasunori; Kato, Chiho; Uchima Koecklin, Karin Harumi; Okihara, Hidemasa; Ishida, Takayoshi; Fujita, Koichi; Yabushita, Tadachika; Kokai, Satoshi; Ono, Takashi

2017-06-01

Postnatal growth is influenced by genetic and environmental factors. Nasal obstruction during growth alters the electromyographic activity of orofacial muscles. The facial primary motor area represents muscles of the tongue and jaw, which are essential in regulating orofacial motor functions, including chewing and jaw opening. This study aimed to evaluate the effect of chronic unilateral nasal obstruction during growth on the motor representations within the face primary motor cortex (M1). Seventy-two 6-day-old male Wistar rats were randomly divided into control ( n = 36) and experimental ( n = 36) groups. Rats in the experimental group underwent unilateral nasal obstruction after cauterization of the external nostril at 8 days of age. Intracortical microstimulation (ICMS) mapping was performed when the rats were 5, 7, 9, and 11 wk old in control and experimental groups ( n = 9 per group per time point). Repeated-measures multivariate ANOVA was used for intergroup and intragroup statistical comparisons. In the control and experimental groups, the total number of positive ICMS sites for the genioglossus and anterior digastric muscles was significantly higher at 5, 7, and 9 wk, but there was no significant difference between 9 and 11 wk of age. Moreover, the total number of positive ICMS sites was significantly smaller in the experimental group than in the control at each age. It is possible that nasal obstruction induced the initial changes in orofacial motor behavior in response to the altered respiratory pattern, which eventually contributed to face-M1 neuroplasticity. NEW & NOTEWORTHY Unilateral nasal obstruction in rats during growth periods induced changes in arterial oxygen saturation (SpO 2 ) and altered development of the motor representation within the face primary cortex. Unilateral nasal obstruction occurring during growth periods may greatly affect not only respiratory function but also craniofacial function in rats. Nasal obstruction should be treated as soon as possible to avoid adverse effects on normal growth, development, and physiological functions. Copyright © 2017 the American Physiological Society.

Modification of dendritic development.

PubMed

Feria-Velasco, Alfredo; del Angel, Alma Rosa; Gonzalez-Burgos, Ignacio

2002-01-01

Since 1890 Ramón y Cajal strongly defended the theory that dendrites and their processes and spines had a function of not just nutrient transport to the cell body, but they had an important conductive role in neural impulse transmission. He extensively discussed and supported this theory in the Volume 1 of his extraordinary book Textura del Sistema Nervioso del Hombre y de los Vertebrados. Also, Don Santiago significantly contributed to a detailed description of the various neural components of the hippocampus and cerebral cortex during development. Extensive investigation has been done in the last Century related to the functional role of these complex brain regions, and their association with learning, memory and some limbic functions. Likewise, the organization and expression of neuropsychological qualities such as memory, exploratory behavior and spatial orientation, among others, depend on the integrity and adequate functional activity of the cerebral cortex and hippocampus. It is known that brain serotonin synthesis and release depend directly and proportionally on the availability of its precursor, tryptophan (TRY). By using a chronic TRY restriction model in rats, we studied their place learning ability in correlation with the dendritic spine density of pyramidal neurons in field CA1 of the hippocampus during postnatal development. We have also reported alterations in the maturation pattern of the ability for spontaneous alternation and task performance evaluating short-term memory, as well as adverse effects on the density of dendritic spines of hippocampal CA1 field pyramidal neurons and on the dendritic arborization and the number of dendritic spines of pyramidal neurons from the third layer of the prefrontal cortex using the same model of TRY restriction. The findings obtained in these studies employing a modified Golgi method, can be interpreted as a trans-synaptic plastic response due to understimulation of serotoninergic receptors located in the hippocampal Ammon's horn and, particularly, on the CA1 field pyramidal neurons, as well as on afferences to the hippocampus which needs to be further investigated.

Postnatal exposure to methyl mercury from fish consumption: a review and new data from the Seychelles Child Development Study.

PubMed

Myers, Gary J; Thurston, Sally W; Pearson, Alexander T; Davidson, Philip W; Cox, Christopher; Shamlaye, Conrad F; Cernichiari, Elsa; Clarkson, Thomas W

2009-05-01

Fish is an important source of nutrition worldwide. Fish contain both the neurotoxin methyl mercury (MeHg) and nutrients important for brain development. The developing brain appears to be most sensitive to MeHg toxicity and mothers who consume fish during pregnancy expose their fetus prenatally. Although brain development is most dramatic during fetal life, it continues for years postnatally and additional exposure can occur when a mother breast feeds or the child consumes fish. This raises the possibility that MeHg might influence brain development after birth and thus adversely affect children's developmental outcomes. We reviewed postnatal MeHg exposure and the associations that have been published to determine the issues associated with it and then carried out a series of analyses involving alternative metrics of postnatal MeHg exposure in the Seychelles Child Development Study (SCDS) Main Cohort. The SCDS is a prospective longitudinal evaluation of prenatal MeHg exposure from fish consumption. The Main Cohort includes 779 subjects on whom recent postnatal exposure data were collected at the 6-, 19-, 29-, 66-, and 107-month evaluations. We examined the association of recent postnatal MeHg exposure with multiple 66- and 107-month outcomes and then used three types of alternative postnatal exposure metrics to examine their association with the children's intelligence quotient (IQ) at 107 months of age. Recent postnatal exposure at 107 months of age was adversely associated with four endpoints, three in females only. One alternative postnatal metric was beneficially associated with 9-year IQ in males only. We found several associations between postnatal MeHg biomarkers and children's developmental endpoints. However, as has been the case with prenatal MeHg exposure in the SCDS Main Cohort study, no consistent pattern of associations emerged to support a causal relationship.

Consequences of Variations in Genes that affect Dopamine in Prefrontal Cortex

PubMed Central

Diamond, Adele

2008-01-01

Patricia Goldman-Rakic played a groundbreaking role in investigating the cognitive functions subserved by dorsolateral prefrontal cortex and the key role of dopamine in that. The work discussed here builds on that including: 1) Studies of children predicted to have lower levels of prefrontal dopamine but otherwise basically normal brains (children treated for phenylketonuria [PKU]). Those studies changed medical guidelines, improving the children’s lives. 2) Studies of visual impairments (in contrast sensitivity and motion perception) in PKU children due to reduced retinal dopamine and due to excessive phenylalanine during the first postnatal weeks. Those studies, too, changed medical guidelines. 3) Studies of working memory and inhibitory control differences in typically developing children due to differences in catechol-O-methyltransferase (COMT) genotype, which selectively affect prefrontal dopamine levels. 4) Studies of gender differences in the effect of COMT genotype on cognitive performance in older adults. 5) A hypothesis about fundamental differences between attention deficit hyperactivity disorder (ADHD) that includes hyperactivity and ADHD of the inattentive type. Those disorders are hypothesized to differ in the affected neural system, underlying genetics, responsiveness to medication, comorbidities, and cognitive and behavioral profiles. These sound quite disparate but they all grew systematically out the base laid down by Patricia Goldman-Rakic. PMID:17725999

Convergence of Cortical, Thalamocortical, and Callosal Pathways during Human Fetal Development Revealed by Diffusion MRI Tractography.

PubMed

Wang, Rongpin; Wilkinson, Molly; Kane, Tara; Takahashi, Emi

2017-01-01

There has been evidence that during brain development, emerging thalamocortical (TC) and corticothalamic (CT) pathways converge in some brain regions and follow each other's trajectories to their final destinations. Corpus callosal (CC) pathways also emerge at a similar developmental stage, and are known to converge with TC pathways in specific cortical regions in mature brains. Given the functional relationships between TC and CC pathways, anatomical convergence of the two pathways are likely important for their functional integration. However, it is unknown (1) where TC and CT subcortically converge in the human brain, and (2) where TC and CC converge in the cortex of the human brain, due to the limitations of non-invasive methods. The goals of this study were to describe the spatio-temporal relationships in the development of the TC/CT and CC pathways in the human brain, using high-angular resolution diffusion MR imaging (HARDI) tractography. Emerging cortical, TC and CC pathways were identified in postmortem fetal brains ranging from 17 gestational weeks (GW) to 30 GW, as well as in vivo 34-40 GW newborns. Some pathways from the thalami were found to be converged with pathways from the cerebral cortex as early as 17 GW. Such convergence was observed mainly in anterior and middle regions of the brain until 21 GW. At 22 GW and onwards, posterior pathways from the thalami also converged with cortical pathways. Many CC pathways reached the full length up to the cortical surface as early as 17 GW, while pathways linked to thalami (not only TC axons but also including pathways linked to thalamic neuronal migration) reached the cortical surface at and after 20 GW. These results suggest that CC pathways developed earlier than the TC pathways. The two pathways were widespread at early stages, but by 40 GW they condensed and formed groups of pathways that projected to specific regions of the cortex and overlapped in some brain regions. These results suggest that HARDI tractography has the potential to identify developing TC/CT and CC pathways with the timing and location of their convergence in fetal stages persisting in postnatal development.

Convergence of Cortical, Thalamocortical, and Callosal Pathways during Human Fetal Development Revealed by Diffusion MRI Tractography

PubMed Central

Wang, Rongpin; Wilkinson, Molly; Kane, Tara; Takahashi, Emi

2017-01-01

There has been evidence that during brain development, emerging thalamocortical (TC) and corticothalamic (CT) pathways converge in some brain regions and follow each other's trajectories to their final destinations. Corpus callosal (CC) pathways also emerge at a similar developmental stage, and are known to converge with TC pathways in specific cortical regions in mature brains. Given the functional relationships between TC and CC pathways, anatomical convergence of the two pathways are likely important for their functional integration. However, it is unknown (1) where TC and CT subcortically converge in the human brain, and (2) where TC and CC converge in the cortex of the human brain, due to the limitations of non-invasive methods. The goals of this study were to describe the spatio-temporal relationships in the development of the TC/CT and CC pathways in the human brain, using high-angular resolution diffusion MR imaging (HARDI) tractography. Emerging cortical, TC and CC pathways were identified in postmortem fetal brains ranging from 17 gestational weeks (GW) to 30 GW, as well as in vivo 34–40 GW newborns. Some pathways from the thalami were found to be converged with pathways from the cerebral cortex as early as 17 GW. Such convergence was observed mainly in anterior and middle regions of the brain until 21 GW. At 22 GW and onwards, posterior pathways from the thalami also converged with cortical pathways. Many CC pathways reached the full length up to the cortical surface as early as 17 GW, while pathways linked to thalami (not only TC axons but also including pathways linked to thalamic neuronal migration) reached the cortical surface at and after 20 GW. These results suggest that CC pathways developed earlier than the TC pathways. The two pathways were widespread at early stages, but by 40 GW they condensed and formed groups of pathways that projected to specific regions of the cortex and overlapped in some brain regions. These results suggest that HARDI tractography has the potential to identify developing TC/CT and CC pathways with the timing and location of their convergence in fetal stages persisting in postnatal development. PMID:29163000

Behavior and Brain Gene Expression Changes in Mice Exposed to Preimplantation and Prenatal Stress

PubMed Central

Strata, Fabrizio; Giritharan, Gnanaratnam; Sebastiano, Francesca Di; Piane, Luisa Delle; Kao, Chia-Ning; Donjacour, Annemarie

2015-01-01

Preimplantation culture of mouse embryos has been suggested to result in reduced anxiety-like behavior in adulthood. Here, we investigated the effects of in vitro fertilization (IVF), embryo culture, and different diets on anxiety-like behavior using the elevated plus maze (EPM). We hypothesized that exposure to suboptimal conditions during the preimplantation stage would interact with the suboptimal diet to alter behavior. The expression of genes related to anxiety was then assessed by quantitative real-time polymerase chain reaction in various brain regions. When fed a normal diet during gestation and a moderately high-fat Western diet (WD) postnatally, naturally conceived (NC) and IVF mice showed similar anxiety-like behavior on the EPM. However, when fed a low-protein diet prenatally and a high-fat diet postnatally (LP/HF), NC mice showed a modest increase in anxiety-like behavior, whereas IVF mice showed the opposite: a strongly reduced anxiety-like behavior on the EPM. The robust reduction in anxiety-like behavior in IVF males fed the LP/HF diets was, intriguingly, associated with reduced expression of MAO-A, CRFR2, and GABA markers in the hypothalamus and cortex. These findings are discussed in relation to the developmental origin of health and disease hypothesis and the 2-hit model, which suggests that 2 events, occurring at different times in development, can act synergistically with long-term consequences observed during adulthood. PMID:25398605

Influence of hypoxia on excitation and GABAergic inhibition in mature and developing rat neocortex.

PubMed

Luhmann, H J; Kral, T; Heinemann, U

1993-01-01

To analyze the functional consequences of hypoxia on the efficacy of intracortical inhibitory mechanisms mediated by gamma-aminobutyric acid (GABA), extra- and intracellular recordings were obtained from rat primary somatosensory cortex in vitro. Hypoxia, induced by transient N2 aeration, caused a decrease in stimulus-evoked inhibitory postsynaptic potentials (IPSPs), followed by a pronounced anoxic depolarization. Upon reoxygenation, the fast (f-) and long-latency (l-) IPSP showed a positive shift in the reversal potential by 24.4 and 14.9 mV, respectively. The peak conductance of the f- and l-IPSP was reversibly reduced in the postanoxic period by 72% and 94%, respectively. Extracellular field potential recordings and application of a paired-pulse inhibition protocol confirmed the enhanced sensitivity of inhibitory synaptic transmission for transient oxygen deprivation. Intracellular recordings from morphologically or electrophysiologically identified interneurons did not reveal any enhanced susceptibility for hypoxia as compared to pyramidal cells, suggesting that inhibitory neurons are not selectively impaired in their functional properties. Intracellularly recorded spontaneous IPSPs were transiently augmented in the postanoxic period, indicating that presynaptic GABA release was not suppressed. Developmental studies in adult (older than postnatal day 28), juvenile (P14-18), and young (P5-8) neocortical slices revealed a prominent functional resistance of immature tissue for hypoxia. In comparison with adult cortex, the hypoxia-induced reduction in excitatory and inhibitory synaptic transmission was significantly smaller in immature cortex. Our data indicate a hypoxia-induced distinct reduction of postsynaptic GABAergic mechanisms, leading to the manifestation of intracortical hyperexcitability as a possible functional consequence.

Developmental Changes in Sensory-Evoked Optical Intrinsic Signals in the Rat Barrel Cortex.

PubMed

Sintsov, Mikhail; Suchkov, Dmitrii; Khazipov, Rustem; Minlebaev, Marat

2017-01-01

Optical Intrinsic Signal imaging (OISi) is a powerful technique for optical brain studies. OIS mainly reflects the hemodynamic response (HR) and metabolism, but it may also involve changes in tissue light scattering (LS) caused by transient cellular swelling in the active tissue. Here, we explored the developmental features of sensory-evoked OIS in the rat barrel cortex during the first 3 months after birth. Multispectral OISi revealed that two temporally distinct components contribute to the neonatal OIS: an early phase of LS followed by a late phase of HR. The contribution of LS to the early response was also evidenced by an increase in light transmission through the active barrel. The early OIS phase correlated in time and amplitude with the sensory-evoked electrophysiological response. Application of the Modified Beer-Lambert Law (MBLL) to the OIS data revealed that HR during the early phase involved only a slight decrease in blood oxygenation without any change in blood volume. In contrast, HR during the late phase manifested an adult-like increase in blood volume and oxygenation. During development, the peak time of the delayed HR progressively shortened with age, nearly reaching the stimulus onset and overlapping with the early LS phase by the fourth postnatal week. Thus, LS contributes to the sensory-evoked OIS in the barrel cortex of rats at all ages, and it dominates the early OIS phase in neonatal rats due to delayed HR. Our results are also consistent with the delayed blood oxygen level dependent (BOLD) signal in human preterm infants.

Developmental Changes in Sensory-Evoked Optical Intrinsic Signals in the Rat Barrel Cortex

PubMed Central

Sintsov, Mikhail; Suchkov, Dmitrii; Khazipov, Rustem; Minlebaev, Marat

2017-01-01

Optical Intrinsic Signal imaging (OISi) is a powerful technique for optical brain studies. OIS mainly reflects the hemodynamic response (HR) and metabolism, but it may also involve changes in tissue light scattering (LS) caused by transient cellular swelling in the active tissue. Here, we explored the developmental features of sensory-evoked OIS in the rat barrel cortex during the first 3 months after birth. Multispectral OISi revealed that two temporally distinct components contribute to the neonatal OIS: an early phase of LS followed by a late phase of HR. The contribution of LS to the early response was also evidenced by an increase in light transmission through the active barrel. The early OIS phase correlated in time and amplitude with the sensory-evoked electrophysiological response. Application of the Modified Beer-Lambert Law (MBLL) to the OIS data revealed that HR during the early phase involved only a slight decrease in blood oxygenation without any change in blood volume. In contrast, HR during the late phase manifested an adult-like increase in blood volume and oxygenation. During development, the peak time of the delayed HR progressively shortened with age, nearly reaching the stimulus onset and overlapping with the early LS phase by the fourth postnatal week. Thus, LS contributes to the sensory-evoked OIS in the barrel cortex of rats at all ages, and it dominates the early OIS phase in neonatal rats due to delayed HR. Our results are also consistent with the delayed blood oxygen level dependent (BOLD) signal in human preterm infants. PMID:29311827

Lgr5(+ve) stem/progenitor cells contribute to nephron formation during kidney development.

PubMed

Barker, Nick; Rookmaaker, Maarten B; Kujala, Pekka; Ng, Annie; Leushacke, Marc; Snippert, Hugo; van de Wetering, Marc; Tan, Shawna; Van Es, Johan H; Huch, Meritxell; Poulsom, Richard; Verhaar, Marianne C; Peters, Peter J; Clevers, Hans

2012-09-27

Multipotent stem cells and their lineage-restricted progeny drive nephron formation within the developing kidney. Here, we document expression of the adult stem cell marker Lgr5 in the developing kidney and assess the stem/progenitor identity of Lgr5(+ve) cells via in vivo lineage tracing. The appearance and localization of Lgr5(+ve) cells coincided with that of the S-shaped body around embryonic day 14. Lgr5 expression remained restricted to cell clusters within developing nephrons in the cortex until postnatal day 7, when expression was permanently silenced. In vivo lineage tracing identified Lgr5 as a marker of a stem/progenitor population within nascent nephrons dedicated to generating the thick ascending limb of Henle's loop and distal convoluted tubule. The Lgr5 surface marker and experimental models described here will be invaluable for deciphering the contribution of early nephron stem cells to developmental defects and for isolating human nephron progenitors as a prerequisite to evaluating their therapeutic potential. Copyright © 2012 The Authors. Published by Elsevier Inc. All rights reserved.

Low-dose penicillin in early life induces long-term changes in murine gut microbiota, brain cytokines and behavior

PubMed Central

Leclercq, Sophie; Mian, Firoz M.; Stanisz, Andrew M.; Bindels, Laure B.; Cambier, Emmanuel; Ben-Amram, Hila; Koren, Omry; Forsythe, Paul; Bienenstock, John

2017-01-01

There is increasing concern about potential long-term effects of antibiotics on children's health. Epidemiological studies have revealed that early-life antibiotic exposure can increase the risk of developing immune and metabolic diseases, and rodent studies have shown that administration of high doses of antibiotics has long-term effects on brain neurochemistry and behaviour. Here we investigate whether low-dose penicillin in late pregnancy and early postnatal life induces long-term effects in the offspring of mice. We find that penicillin has lasting effects in both sexes on gut microbiota, increases cytokine expression in frontal cortex, modifies blood–brain barrier integrity and alters behaviour. The antibiotic-treated mice exhibit impaired anxiety-like and social behaviours, and display aggression. Concurrent supplementation with Lactobacillus rhamnosus JB-1 prevents some of these alterations. These results warrant further studies on the potential role of early-life antibiotic use in the development of neuropsychiatric disorders, and the possible attenuation of these by beneficial bacteria. PMID:28375200

Developmental expression of membrane type 4-matrix metalloproteinase (Mt4-mmp/Mmp17) in the mouse embryo

PubMed Central

Clemente, Cristina; Montalvo, María Gregoria; Seiki, Motoharu; Arroyo, Alicia G.

2017-01-01

Matrix metalloproteinases (MMPs) constitute a large group of endoproteases that play important functions during embryonic development, tumor metastasis and angiogenesis by degrading components of the extracellular matrix. Within this family, we focused our study on Mt4-mmp (also called Mmp17) that belongs to a distinct subset that is anchored to the cell surface via a glycosylphosphatidylinositol (GPI) moiety and with the catalytic site exposed to the extracellular space. Information about its function and substrates is very limited to date, and little has been reported on its role in the developing embryo. Here, we report a detailed expression analysis of Mt4-mmp during mouse embryonic development by using a LacZ reporter transgenic mouse line. We showed that Mt4-mmp is detected from early stages of development to postnatal stages following a dynamic and restricted pattern of expression. Mt4-mmp was first detected at E8.5 limited to the intersomitic vascularization, the endocardial endothelium and the dorsal aorta. Mt4-mmpLacZ/+ cells were also observed in the neural crest cells, somites, floor plate and notochord at early stages. From E10.5, expression localized in the limb buds and persists during limb development. A strong expression in the brain begins at E12.5 and continues to postnatal stages. Specifically, staining was observed in the olfactory bulb, cerebral cortex, hippocampus, striatum, septum, dorsal thalamus and the spinal cord. In addition, LacZ-positive cells were also detected during eye development, initially at the hyaloid artery and later on located in the lens and the neural retina. Mt4-mmp expression was confirmed by quantitative RT-PCR and western blot analysis in some embryonic tissues. Our data point to distinct functions for this metalloproteinase during embryonic development, particularly during brain formation, angiogenesis and limb development. PMID:28926609

Methylphenidate alleviates manganese-induced impulsivity but not distractibility

PubMed Central

Beaudin, Stephane A.; Strupp, Barbara J.; Uribe, Walter; Ysais, Lauren; Strawderman, Myla; Smith, Donald R.

2017-01-01

Recent studies from our lab have demonstrated that postnatal manganese (Mn) exposure in a rodent model can cause lasting impairments in fine motor control and attention, and that oral methylphenidate (MPH) treatment can effectively treat the dysfunction in fine motor control. However, it is unknown whether MPH treatment can alleviate the impairments in attention produced by Mn exposure. Here we used a rodent model of postnatal Mn exposure to determine whether (1) oral MPH alleviates attention and impulse control deficits caused by postnatal Mn exposure, using attention tasks that are variants of the 5-choice serial reaction time task, and (2) whether these treatments affected neuronal dendritic spine density in the medial prefrontal cortex (mPFC) and dorsal striatum. Male Long-Evans rats were exposed orally to 0 or 50 mg Mn/kg/d throughout life starting on PND 1, and tested as young adults (PND 107 – 115) on an attention task that specifically tapped selective attention and impulse control. Animals were treated with oral MPH (2.5 mg/kg/d) throughout testing on the attention task. Our findings show that lifelong postnatal Mn exposure impaired impulse control and selective attention in young adulthood, and that a therapeutically relevant oral MPH regimen alleviated the Mn-induced dysfunction in impulse control, but not selective attention, and actually impaired focused attention in the Mn group. In addition, the effect of MPH was qualitatively different for the Mn-exposed versus control animals across a range of behavioral measures of inhibitory control and attention, as well as dendritic spine density in the mPFC, suggesting that postnatal Mn exposure alters catecholaminergic systems modulating these behaviors. Collectively these findings suggest that MPH may hold promise for treating the behavioral dysfunction caused by developmental Mn exposure, although further research is needed with multiple MPH doses to determine whether a dose can be identified that ameliorates the dysfunction in both impulse control and selective attention, without impairing focused attention. PMID:28363668

Postnatal Changes in K+/Cl- Cotransporter-2 Expression in the Forebrain of Mice Bearing a Mutant Nicotinic Subunit Linked to Sleep-Related Epilepsy.

PubMed

Amadeo, Alida; Coatti, Aurora; Aracri, Patrizia; Ascagni, Miriam; Iannantuoni, Davide; Modena, Debora; Carraresi, Laura; Brusco, Simone; Meneghini, Simone; Arcangeli, Annarosa; Pasini, Maria Enrica; Becchetti, Andrea

2018-06-24

The Na + /K + /Cl - cotransporter-1 (NKCC1) and the K + /Cl - cotransporter-2 (KCC2) set the transmembrane Cl - gradient in the brain, and are implicated in epileptogenesis. We studied the postnatal distribution of NKCC1 and KCC2 in wild-type (WT) mice, and in a mouse model of sleep-related epilepsy, carrying the mutant β2-V287L subunit of the nicotinic acetylcholine receptor (nAChR). In WT neocortex, immunohistochemistry showed a wide distribution of NKCC1 in neurons and astrocytes. At birth, KCC2 was localized in neuronal somata, whereas at subsequent stages it was mainly found in the somatodendritic compartment. The cotransporters' expression was quantified by densitometry in the transgenic strain. KCC2 expression increased during the first postnatal weeks, while the NKCC1 amount remained stable, after birth. In mice expressing β2-V287L, the KCC2 amount in layer V of prefrontal cortex (PFC) was lower than in the control littermates at postnatal day 8 (P8), with no concomitant change in NKCC1. Consistently, the GABAergic excitatory to inhibitory switch was delayed in PFC layer V of mice carrying β2-V287L. At P60, the amount of KCC2 was instead higher in mice bearing the transgene. Irrespective of genotype, NKCC1 and KCC2 were abundantly expressed in the neuropil of most thalamic nuclei since birth. However, KCC2 expression decreased by P60 in the reticular nucleus, and more so in mice expressing β2-V287L. Therefore, a complex regulatory interplay occurs between heteromeric nAChRs and KCC2 in postnatal forebrain. The pathogenetic effect of β2-V287L may depend on altered KCC2 amounts in PFC during synaptogenesis, as well as in mature thalamocortical circuits. Copyright © 2018. Published by Elsevier Ltd.

Methylphenidate alleviates manganese-induced impulsivity but not distractibility.

PubMed

Beaudin, Stephane A; Strupp, Barbara J; Uribe, Walter; Ysais, Lauren; Strawderman, Myla; Smith, Donald R

2017-05-01

Recent studies from our lab have demonstrated that postnatal manganese (Mn) exposure in a rodent model can cause lasting impairments in fine motor control and attention, and that oral methylphenidate (MPH) treatment can effectively treat the dysfunction in fine motor control. However, it is unknown whether MPH treatment can alleviate the impairments in attention produced by Mn exposure. Here we used a rodent model of postnatal Mn exposure to determine whether (1) oral MPH alleviates attention and impulse control deficits caused by postnatal Mn exposure, using attention tasks that are variants of the 5-choice serial reaction time task, and (2) whether these treatments affected neuronal dendritic spine density in the medial prefrontal cortex (mPFC) and dorsal striatum. Male Long-Evans rats were exposed orally to 0 or 50Mn/kg/d throughout life starting on PND 1, and tested as young adults (PND 107-115) on an attention task that specifically tapped selective attention and impulse control. Animals were treated with oral MPH (2.5mg/kg/d) throughout testing on the attention task. Our findings show that lifelong postnatal Mn exposure impaired impulse control and selective attention in young adulthood, and that a therapeutically relevant oral MPH regimen alleviated the Mn-induced dysfunction in impulse control, but not selective attention, and actually impaired focused attention in the Mn group. In addition, the effect of MPH was qualitatively different for the Mn-exposed versus control animals across a range of behavioral measures of inhibitory control and attention, as well as dendritic spine density in the mPFC, suggesting that postnatal Mn exposure alters catecholaminergic systems modulating these behaviors. Collectively these findings suggest that MPH may hold promise for treating the behavioral dysfunction caused by developmental Mn exposure, although further research is needed with multiple MPH doses to determine whether a dose can be identified that ameliorates the dysfunction in both impulse control and selective attention, without impairing focused attention. Copyright © 2017 Elsevier Inc. All rights reserved.

Myelination progression in language-correlated regions in brain of normal children determined by quantitative MRI assessment.

PubMed

Su, Peijen; Kuan, Chen-Chieh; Kaga, Kimitaka; Sano, Masaki; Mima, Kazuo

2008-12-01

To investigate the myelination progression course in language-correlated regions of children with normal brain development by quantitative magnetic resonance imaging (MRI) analysis compared with histological studies. The subjects were 241 neurologically intact neonates, infants and young children (128 boys and 113 girls) who underwent MRI between 2001 and 2007 at the University of Tokyo Hospital, ranging in age from 0 to 429 weeks corrected by postnatal age. To compare their data with adult values, 25 adolescents and adults (14 men and 11 women, aged from 14 to 83 years) were examined as controls. Axial T2-weighted images were obtained using spin-echo sequences at 1.5 T. Subjects with a history of prematurity, birth asphyxia, low Apgar score, seizures, active systemic disease, congenital anomaly, delayed development, infarcts, hemorrhages, brain lesions, or central nervous system malformation were excluded from the analysis. Seven regions of interest in language-correlated areas, namely Broca's area, Wernicke's area, the arcuate fasciculus, and the angular gyrus, as well as their right hemisphere homologous regions, and the auditory cortex, the motor cortex, and the visual cortex were examined. Signal intensity obtained by a region-of-interest methodology progresses from hyper- to hypointensity during myelination. We chose the inferior cerebellar peduncle as the internal standard of maturation. Myelination in all these seven language-correlated regions examined in this study shared the same curve pattern: no myelination was observed at birth, it reached maturation at about 1.5 years of age, and it continued to progress slowly thereafter into adult life. On the basis of scatter plot results, we put these areas into three groups: Group A, which included the motor cortex, the auditory cortex, and the visual cortex, myelinated faster than Group B, which included Broca's area, Wernicke's area, and the angular gyrus before 1.5 years old; Group C, consisting of the arcuate fasciculus, has similar degree of myelination as Group B before 1.5 years but then myelinated more slowly after 3 years of age. No gender or left-right differences between homologous regions were found. In this study, we determined the sequence of myelination of language-correlated regions in infants and children by quantitative MRI assessment. The higher cortical areas matured later than the primary cortical areas, and the arcuate fasciculus matured last. The observation that myelination reaches maturity after 18 months suggests that myelination may be a reason for the acceleration in vocabulary acquisition observed in children from that age. The slow pace of myelination also suggested the possibility of language development's continuation into early adult life. Myelination assessed by MRI was at least 1 month behind that assessed by histological staining. No gender or left-right hemisphere differences in myelination were noted.

Using motor behavior during an early critical period to restore skilled limb movement after damage to the corticospinal motor system during development

PubMed Central

Friel, KM; Chakrabarty, S; H-C, Kuo; Martin, JH

2012-01-01

This study investigated requirements for restoring motor function after corticospinal (CS) system damage during early postnatal development. Activity-dependent competition between the CS tracts (CST) of the two hemispheres is imperative for normal development. Blocking primary motor cortex (M1) activity unilaterally during a critical period (postnatal weeks-PW-5–7) produces permanent contralateral motor skill impairments, loss of M1 motor map, aberrant CS terminations, and decreases in CST presynaptic sites and spinal cholinergic interneuron numbers. To repair these motor systems impairments and restore function, we manipulated motor experience in three groups of cats after this CST injury produced by inactivation. One group wore a jacket restraining the limb ipsilateral to inactivation, forcing use of the contralateral, impaired, limb, for the month following M1 inactivation (PW8–13; “Restraint Alone”). A second group wore the restraint during PW8–13, and was also trained for 1 h/day in a reaching task with the contralateral forelimb (“Early Training”). To test the efficacy of intervention during adolescence, a third group wore the restraint and received reach training during PW20–24 (“Delayed Training”). Early training restored CST connections and the M1 motor map; increased cholinergic spinal interneurons numbers on the contralateral, relative to ipsilateral, side; and abrogated limb control impairments. Delayed training restored CST connectivity and the M1 motor map, but not contralateral spinal cholinergic cell counts or motor performance. Restraint alone only restored CST connectivity. Our findings stress the need to reestablish the integrated functions of the CS system at multiple hierarchical levels in restoring skilled motor function after developmental injury. PMID:22764234

Comparative study of the effects of experimentally induced hypothyroidism and hyperthyroidism in some brain regions in albino rats.

PubMed

El-Bakry, A M; El-Gareib, A W; Ahmed, R G

2010-08-01

Thyroid hormones (THs) play a crucial role in the development and physiological functioning of different body organs especially the brain. Therefore, the objective of this study was to show the histopathological effects of the different thyroid states on some brain regions (cerebrum and cerebellum) and the skeletal features of their newborns during the postnatal development from the 1st to 3rd week. The female white albino rats were allocated into 3 groups as follows: the experimental hypothyroidism group is induced by 0.02% methimazole (MMI) (w/v) in drinking water, while the experimental hyperthyroidism group is performed by exogenous T4 [from 50 to 200microg/kg body weight intragastric administration beside adding 0.002% T4 (w/v) to the drinking water] from the gestation day 1 to lactation day 21 and control group which received tap water. As well, both maternal hypo- and hyperthyroidism caused some malformation and developmental defects in the cerebellar and cerebral cortex of their newborns along the duration of the experiment. These degenerative symptoms became more prominent and widely spread at the 3rd postnatal week. Concomitantly, there were some degeneration, deformation and severe growth retardation in neurons of these regions in both treated groups throughout the experimental period. Moreover, the skeletal features of these newborns were accelerated in hyperthyroid group while these maturations were delayed partially in hypothyroid ones during the examined periods. These alterations, on both treated groups, were age and dose dependent. Thus, further studies need to be done to emphasize this concept. Published by Elsevier Ltd.

Prenatal Drug Exposures Sensitize Noradrenergic Circuits to Subsequent Disruption by Chlorpyrifos

PubMed Central

Slotkin, Theodore A.; Skavicus, Samantha; Seidler, Frederic J.

2015-01-01

We examined whether nicotine or dexamethasone, common prenatal drug exposures, sensitize the developing brain to chlorpyrifos. We gave nicotine to pregnant rats throughout gestation at a dose (3 mg/kg/day) producing plasma levels typical of smokers; offspring were then given chlorpyrifos on postnatal days 1–4, at a dose (1 mg/kg) that produces minimally-detectable inhibition of brain cholinesterase activity. In a parallel study, we administered dexamethasone to pregnant rats on gestational days 17–19 at a standard therapeutic dose (0.2 mg/kg) used in the management of preterm labor, followed by postnatal chlorpyrifos. We evaluated cerebellar noradrenergic projections, a known target for each agent, and contrasted the effects with those in the cerebral cortex. Either drug augmented the effect of chlorpyrifos, evidenced by deficits in cerebellar β-adrenergic receptors; the receptor effects were not due to increased systemic toxicity or cholinesterase inhibition, nor to altered chlorpyrifos pharmacokinetics. Further, the deficits were not secondary adaptations to presynaptic hyperinnervation/hyperactivity, as there were significant deficits in presynaptic norepinephrine levels that would serve to augment the functional consequence of receptor deficits. The pretreatments also altered development of cerebrocortical noradrenergic circuits, but with a different overall pattern, reflecting the dissimilar developmental stages of the regions at the time of exposure. However, in each case the net effects represented a change in the developmental trajectory of noradrenergic circuits, rather than simply a continuation of an initial injury. Our results point to the ability of prenatal drug exposure to create a subpopulation with heightened vulnerability to environmental neurotoxicants. PMID:26419632

Prenatal drug exposures sensitize noradrenergic circuits to subsequent disruption by chlorpyrifos.

PubMed

Slotkin, Theodore A; Skavicus, Samantha; Seidler, Frederic J

2015-12-02

We examined whether nicotine or dexamethasone, common prenatal drug exposures, sensitize the developing brain to chlorpyrifos. We gave nicotine to pregnant rats throughout gestation at a dose (3mg/kg/day) producing plasma levels typical of smokers; offspring were then given chlorpyrifos on postnatal days 1-4, at a dose (1mg/kg) that produces minimally-detectable inhibition of brain cholinesterase activity. In a parallel study, we administered dexamethasone to pregnant rats on gestational days 17-19 at a standard therapeutic dose (0.2mg/kg) used in the management of preterm labor, followed by postnatal chlorpyrifos. We evaluated cerebellar noradrenergic projections, a known target for each agent, and contrasted the effects with those in the cerebral cortex. Either drug augmented the effect of chlorpyrifos, evidenced by deficits in cerebellar β-adrenergic receptors; the receptor effects were not due to increased systemic toxicity or cholinesterase inhibition, nor to altered chlorpyrifos pharmacokinetics. Further, the deficits were not secondary adaptations to presynaptic hyperinnervation/hyperactivity, as there were significant deficits in presynaptic norepinephrine levels that would serve to augment the functional consequence of receptor deficits. The pretreatments also altered development of cerebrocortical noradrenergic circuits, but with a different overall pattern, reflecting the dissimilar developmental stages of the regions at the time of exposure. However, in each case the net effects represented a change in the developmental trajectory of noradrenergic circuits, rather than simply a continuation of an initial injury. Our results point to the ability of prenatal drug exposure to create a subpopulation with heightened vulnerability to environmental neurotoxicants. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Volume electron microscopy of the distribution of synapses in the neuropil of the juvenile rat somatosensory cortex.

PubMed

Santuy, A; Rodriguez, J R; DeFelipe, J; Merchan-Perez, A

2018-01-01

Knowing the proportions of asymmetric (excitatory) and symmetric (inhibitory) synapses in the neuropil is critical for understanding the design of cortical circuits. We used focused ion beam milling and scanning electron microscopy (FIB/SEM) to obtain stacks of serial sections from the six layers of the juvenile rat (postnatal day 14) somatosensory cortex (hindlimb representation). We segmented in three-dimensions 6184 synaptic junctions and determined whether they were established on dendritic spines or dendritic shafts. Of all these synapses, 87-94% were asymmetric and 6-13% were symmetric. Asymmetric synapses were preferentially located on dendritic spines in all layers (80-91%) while symmetric synapses were mainly located on dendritic shafts (62-86%). Furthermore, we found that less than 6% of the dendritic spines establish more than one synapse. The vast majority of axospinous synapses were established on the spine head. Synapses on the spine neck were scarce, although they were more common when the dendritic spine established multiple synapses. This study provides a new large quantitative dataset that may contribute not only to the knowledge of the ultrastructure of the cortex, but also towards defining the connectivity patterns through all cortical layers.

Vibrissae-evoked behavior and conditioning before functional ontogeny of the somatosensory vibrissae cortex.

PubMed

Landers, M S; Sullivan, R M

1999-06-15

The following experiments determined that the somatosensory whisker system is functional and capable of experience-dependent behavioral plasticity in the neonate before functional maturation of the somatosensory whisker cortex. First, unilateral whisker stimulation caused increased behavioral activity in both postnatal day (P) 3-4 and P8 pups, whereas stimulation-evoked cortical activity (14C 2-deoxyglucose autoradiography) was detectable only in P8 pups. Second, neonatal rat pups are capable of forming associations between whisker stimulation and a reinforcer. A classical conditioning paradigm (P3-P4) showed that the learning groups (paired whisker stimulation-shock or paired whisker stimulation-warm air stream) exhibited significantly higher behavioral responsiveness to whisker stimulation than controls. Finally, stimulus-evoked somatosensory cortical activity during testing [P8; using 14C 2-deoxyglucose (2-DG) autoradiography] was assessed after somatosensory conditioning from P1-P8. No learning-associated differences in stimulus-evoked cortical activity were detected between learning and nonlearning control groups. Together, these experiments demonstrate that the whisker system is functional in neonates and capable of experience-dependent behavioral plasticity. Furthermore, in contrast to adult somatosensory classical conditioning, these data suggest that the cortex is not required for associative somatosensory learning in neonates.

Environmental enrichment accelerates ocular dominance plasticity in mouse visual cortex whereas transfer to standard cages resulted in a rapid loss of increased plasticity.

PubMed

Kalogeraki, Evgenia; Pielecka-Fortuna, Justyna; Löwel, Siegrid

2017-01-01

In standard cage (SC) raised mice, experience-dependent ocular dominance (OD) plasticity in the primary visual cortex (V1) rapidly declines with age: in postnatal day 25-35 (critical period) mice, 4 days of monocular deprivation (MD) are sufficient to induce OD-shifts towards the open eye; thereafter, 7 days of MD are needed. Beyond postnatal day 110, even 14 days of MD failed to induce OD-plasticity in mouse V1. In contrast, mice raised in a so-called "enriched environment" (EE), exhibit lifelong OD-plasticity. EE-mice have more voluntary physical exercise (running wheels), and experience more social interactions (bigger housing groups) and more cognitive stimulation (regularly changed labyrinths or toys). Whether experience-dependent shifts of V1-activation happen faster in EE-mice and how long the plasticity promoting effect would persist after transferring EE-mice back to SCs has not yet been investigated. To this end, we used intrinsic signal optical imaging to visualize V1-activation i) before and after MD in EE-mice of different age groups (from 1-9 months), and ii) after transferring mice back to SCs after postnatal day 130. Already after 2 days of MD, and thus much faster than in SC-mice, EE-mice of all tested age groups displayed a significant OD-shift towards the open eye. Transfer of EE-mice to SCs immediately abolished OD-plasticity: already after 1 week of SC-housing and MD, OD-shifts could no longer be visualized. In an attempt to rescue abolished OD-plasticity of these mice, we either administered the anti-depressant fluoxetine (in drinking water) or supplied a running wheel in the SCs. OD-plasticity was only rescued for the running wheel- mice. Altogether our results show that raising mice in less deprived environments like large EE-cages strongly accelerates experience-dependent changes in V1-activation compared to the impoverished SC-raising. Furthermore, preventing voluntary physical exercise of EE-mice in adulthood immediately precludes OD-shifts in V1.

Environmental enrichment accelerates ocular dominance plasticity in mouse visual cortex whereas transfer to standard cages resulted in a rapid loss of increased plasticity

PubMed Central

Pielecka-Fortuna, Justyna; Löwel, Siegrid

2017-01-01

In standard cage (SC) raised mice, experience-dependent ocular dominance (OD) plasticity in the primary visual cortex (V1) rapidly declines with age: in postnatal day 25–35 (critical period) mice, 4 days of monocular deprivation (MD) are sufficient to induce OD-shifts towards the open eye; thereafter, 7 days of MD are needed. Beyond postnatal day 110, even 14 days of MD failed to induce OD-plasticity in mouse V1. In contrast, mice raised in a so-called “enriched environment” (EE), exhibit lifelong OD-plasticity. EE-mice have more voluntary physical exercise (running wheels), and experience more social interactions (bigger housing groups) and more cognitive stimulation (regularly changed labyrinths or toys). Whether experience-dependent shifts of V1-activation happen faster in EE-mice and how long the plasticity promoting effect would persist after transferring EE-mice back to SCs has not yet been investigated. To this end, we used intrinsic signal optical imaging to visualize V1-activation i) before and after MD in EE-mice of different age groups (from 1–9 months), and ii) after transferring mice back to SCs after postnatal day 130. Already after 2 days of MD, and thus much faster than in SC-mice, EE-mice of all tested age groups displayed a significant OD-shift towards the open eye. Transfer of EE-mice to SCs immediately abolished OD-plasticity: already after 1 week of SC-housing and MD, OD-shifts could no longer be visualized. In an attempt to rescue abolished OD-plasticity of these mice, we either administered the anti-depressant fluoxetine (in drinking water) or supplied a running wheel in the SCs. OD-plasticity was only rescued for the running wheel- mice. Altogether our results show that raising mice in less deprived environments like large EE-cages strongly accelerates experience-dependent changes in V1-activation compared to the impoverished SC-raising. Furthermore, preventing voluntary physical exercise of EE-mice in adulthood immediately precludes OD-shifts in V1. PMID:29073219

Neural cell adhesion molecule, NCAM, regulates thalamocortical axon pathfinding and the organization of the cortical somatosensory representation in mouse

PubMed Central

Enriquez-Barreto, Lilian; Palazzetti, Cecilia; Brennaman, Leann H.; Maness, Patricia F.; Fairén, Alfonso

2012-01-01

To study the potential role of neural cell adhesion molecule (NCAM) in the development of thalamocortical (TC) axon topography, wild type, and NCAM null mutant mice were analyzed for NCAM expression, projection, and targeting of TC afferents within the somatosensory area of the neocortex. Here we report that NCAM and its α-2,8-linked polysialic acid (PSA) are expressed in developing TC axons during projection to the neocortex. Pathfinding of TC axons in wild type and null mutant mice was mapped using anterograde DiI labeling. At embryonic day E16.5, null mutant mice displayed misguided TC axons in the dorsal telencephalon, but not in the ventral telencephalon, an intermediate target that initially sorts TC axons toward correct neocortical areas. During the early postnatal period, rostrolateral TC axons within the internal capsule along the ventral telencephalon adopted distorted trajectories in the ventral telencephalon and failed to reach the neocortex in NCAM null mutant animals. NCAM null mutants showed abnormal segregation of layer IV barrels in a restricted portion of the somatosensory cortex. As shown by Nissl and cytochrome oxidase staining, barrels of the anterolateral barrel subfield (ALBSF) and the most distal barrels of the posteromedial barrel subfield (PMBSF) did not segregate properly in null mutant mice. These results indicate a novel role for NCAM in axonal pathfinding and topographic sorting of TC axons, which may be important for the function of specific territories of sensory representation in the somatosensory cortex. PMID:22723769

Neurobehavioral assessment of maternal odor in developing rat pups: implications for social buffering

PubMed Central

Al Aïn, Syrina; Perry, Rosemarie E.; Nuñez, Bestina; Kayser, Kassandra; Hochman, Chase; Brehman, Elizabeth; LaComb, Miranda; Wilson, Donald A.; Sullivan, Regina M.

2016-01-01

Social support can attenuate the behavioral and stress hormone response to threat, a phenomenon called social buffering. The mother’s social buffering of the infant is one of the more robust examples; yet we understand little about the neurobiology. Using a rodent model, we explore the neurobiology of social buffering by assessing neural processing of the maternal odor, a major cue controlling social buffering in rat pups. We used pups before (postnatal day (PN) 7) and after (PN14, PN23) the functional emergence of social buffering. Pups were injected with 14C 2-deoxyglucose (2-DG) and presented with the maternal odor, a control preferred odor incapable of social buffering (acetophenone), or no odor. Brains were removed, processed for autoradiography and brain areas identified as important in adult social buffering were assessed, including the amygdala basolateral complex (Basolateral Amygdala [BLA]), medial prefrontal cortex (mPFC), and anterior cingulate cortex (ACC). Results suggest dramatic changes in the processing of maternal odor. PN7 pups show mPFC and ACC activation, although PN14 pups showed no activation of the mPFC, ACC, or BLA. All brain areas assessed were recruited by PN23. Additional analysis suggests substantial changes in functional connectivity across development. Together, these results imply complex nonlinear transitions in the neurobiology of social buffering in early life that may provide insight into the changing role of the mother in supporting social buffering. PMID:26934130

From genes to brain oscillations: is the visual pathway the epigenetic clue to schizophrenia?

PubMed

González-Hernández, J A; Pita-Alcorta, C; Cedeño, I R

2006-01-01

Molecular data and gene expression data and recently mitochondrial genes and possible epigenetic regulation by non-coding genes is revolutionizing our views on schizophrenia. Genes and epigenetic mechanisms are triggered by cell-cell interaction and by external stimuli. A number of recent clinical and molecular observations indicate that epigenetic factors may be operational in the origin of the illness. Based on the molecular insights, gene expression profiles and epigenetic regulation of gene, we went back to the neurophysiology (brain oscillations) and found a putative role of the visual experiences (i.e. visual stimuli) as epigenetic factor. The functional evidences provided here, establish a direct link between the striate and extrastriate unimodal visual cortex and the neurobiology of the schizophrenia. This result support the hypothesis that 'visual experience' has a potential role as epigenetic factor and contribute to trigger and/or to maintain the progression of the schizophrenia. In this case, candidate genes sensible for the visual 'insult' may be located within the visual cortex including associative areas, while the integrity of the visual pathway before reaching the primary visual cortex is preserved. The same effect can be perceived if target genes are localised within the visual pathway, which actually, is more sensitive for 'insult' during the early life than the cortex per se. If this process affects gene expression at these sites a stably sensory specific 'insult', i.e. distorted visual information, is entering the visual system and expanded to fronto-temporo-parietal multimodal areas even from early maturation periods. The difference in the timing of postnatal neuroanatomical events between such areas and the primary visual cortex in humans (with the formers reaching the same development landmarks later in life than the latter) is 'optimal' to establish an abnormal 'cell- communication' mediated by the visual system that may further interfere with the local physiology. In this context the strategy to search target genes need to be rearrangement and redirected to visual-related genes. Otherwise, psychophysics studies combining functional neuroimage, and electrophysiology are strongly recommended, for the search of epigenetic clues that will allow to carrier gene association studies in schizophrenia.

The mouse cerebellar cortex in organotypic slice cultures: an in vitro model to analyze the consequences of mutations and pathologies on neuronal survival, development, and function.

PubMed

Lonchamp, Etienne; Dupont, Jean-Luc; Beekenkamp, Huguette; Poulain, Bernard; Bossu, Jean-Louis

2006-01-01

Thin acute slices and dissociated cell cultures taken from different parts of the brain have been widely used to examine the function of the nervous system, neuron-specific interactions, and neuronal development (specifically, neurobiology, neuropharmacology, and neurotoxicology studies). Here, we focus on an alternative in vitro model: brain-slice cultures in roller tubes, initially introduced by Beat Gähwiler for studies with rats, that we have recently adapted for studies of mouse cerebellum. Cultured cerebellar slices afford many of the advantages of dissociated cultures of neurons and thin acute slices. Organotypic slice cultures were established from newborn or 10-15-day-old mice. After 3-4 weeks in culture, the slices flattened to form a cell monolayer. The main types of cerebellar neurons could be identified with immunostaining techniques, while their electrophysiological properties could be easily characterized with the patch-clamp recording technique. When slices were taken from newborn mice and cultured for 3 weeks, aspects of the cerebellar development were displayed. A functional neuronal network was established despite the absence of mossy and climbing fibers, which are the two excitatory afferent projections to the cerebellum. When slices were made from 10-15-day-old mice, which are at a developmental stage when cerebellum organization is almost established, the structure and neuronal pathways were intact after 3-4 weeks in culture. These unique characteristics make organotypic slice cultures of mouse cerebellar cortex a valuable model for analyzing the consequences of gene mutations that profoundly alter neuronal function and compromise postnatal survival.

Reelin, an extracellular matrix protein linked to early onset psychiatric diseases, drives postnatal development of the prefrontal cortex via GluN2B-NMDARs and the mTOR pathway

PubMed Central

Iafrati, J; Orejarena, M J; Lassalle, O; Bouamrane, L; Chavis, P

2014-01-01

Defective brain extracellular matrix (ECM) is a factor of vulnerability in various psychiatric diseases such as schizophrenia, depression and autism. The glycoprotein reelin is an essential building block of the brain ECM that modulates neuronal development and participates to the functions of adult central synapses. The reelin gene (RELN) is a strong candidate in psychiatric diseases of early onset, but its synaptic and behavioral functions in juvenile brain circuits remain unresolved. Here, we found that in juvenile reelin-haploinsufficient heterozygous reeler mice (HRM), abnormal fear memory erasure is concomitant to reduced dendritic spine density and anomalous long-term potentiation in the prefrontal cortex. In juvenile HRM, a single in vivo injection with ketamine or Ro25-6981 to inhibit GluN2B-N-methyl-𝒟-aspartate receptors (NMDARs) restored normal spine density, synaptic plasticity and converted fear memory to an erasure-resilient state typical of adult rodents. The functional and behavioral rescue by ketamine was prevented by rapamycin, an inhibitor of the mammalian target of rapamycin pathway. Finally, we show that fear memory erasure persists until adolescence in HRM and that a single exposure to ketamine during the juvenile period reinstates normal fear memory in adolescent mice. Our results show that reelin is essential for successful structural, functional and behavioral development of juvenile prefrontal circuits and that this developmental period provides a critical window for therapeutic rehabilitation with GluN2B-NMDAR antagonists. PMID:23752244

Overnight changes in the slope of sleep slow waves during infancy.

PubMed

Fattinger, Sara; Jenni, Oskar G; Schmitt, Bernhard; Achermann, Peter; Huber, Reto

2014-02-01

Slow wave activity (SWA, 0.5-4.5 Hz) is a well-established marker for sleep pressure in adults. Recent studies have shown that increasing sleep pressure is reflected by an increased synchronized firing pattern of cortical neurons, which can be measured by the slope of sleep slow waves. Thus we aimed at investigating whether the slope of sleep slow waves might provide an alternative marker to study the homeostatic regulation of sleep during early human development. All-night sleep electroencephalography (EEG) was recorded longitudinally at 2, 4, 6, and 9 months after birth. Home recording. 11 healthy full-term infants (5 male, 6 female). None. The slope of sleep slow waves increased with age. At all ages the slope decreased from the first to the last hour of non rapid-eye-movement (NREM) sleep, even when controlling for amplitude differences (P < 0.002). The decrease of the slope was also present in the cycle-by-cycle time course across the night (P < 0.001) at the age of 6 months when the alternating pattern of low-delta activity (0.75-1.75 Hz) is most prominent. Moreover, we found distinct topographical differences exhibiting the steepest slope over the occipital cortex. The results suggest an age-dependent increase in synchronization of cortical activity during infancy, which might be due to increasing synaptogenesis. Previous studies have shown that during early postnatal development synaptogenesis is most pronounced over the occipital cortex, which could explain why the steepest slope was found in the occipital derivation. Our results provide evidence that the homeostatic regulation of sleep develops early in human infants.

Effects of chronic stress in adolescence on learned fear, anxiety, and synaptic transmission in the rat prelimbic cortex.

PubMed

Negrón-Oyarzo, Ignacio; Pérez, Miguel Ángel; Terreros, Gonzalo; Muñoz, Pablo; Dagnino-Subiabre, Alexies

2014-02-01

The prelimbic cortex and amygdala regulate the extinction of conditioned fear and anxiety, respectively. In adult rats, chronic stress affects the dendritic morphology of these brain areas, slowing extinction of learned fear and enhancing anxiety. The aim of this study was to determine whether rats subjected to chronic stress in adolescence show changes in learned fear, anxiety, and synaptic transmission in the prelimbic cortex during adulthood. Male Sprague Dawley rats were subjected to seven days of restraint stress on postnatal day forty-two (PND 42, adolescence). Afterward, the fear-conditioning paradigm was used to study conditioned fear extinction. Anxiety-like behavior was measured one day (PND 50) and twenty-one days (PND 70, adulthood) after stress using the elevated-plus maze and dark-light box tests, respectively. With another set of rats, excitatory synaptic transmission was analyzed with slices of the prelimbic cortex. Rats that had been stressed during adolescence and adulthood had higher anxiety-like behavior levels than did controls, while stress-induced slowing of learned fear extinction in adolescence was reversed during adulthood. As well, the field excitatory postsynaptic potentials of stressed adolescent rats had significantly lower amplitudes than those of controls, although the amplitudes were higher in adulthood. Our results demonstrate that short-term stress in adolescence induces strong effects on excitatory synaptic transmission in the prelimbic cortex and extinction of learned fear, where the effect of stress on anxiety is more persistent than on the extinction of learned fear. These data contribute to the understanding of stress neurobiology. Copyright © 2013 Elsevier B.V. All rights reserved.

Enduring critical period plasticity visualized by transcranial flavoprotein imaging in mouse primary visual cortex.

PubMed

Tohmi, Manavu; Kitaura, Hiroki; Komagata, Seiji; Kudoh, Masaharu; Shibuki, Katsuei

2006-11-08

Experience-dependent plasticity in the visual cortex was investigated using transcranial flavoprotein fluorescence imaging in mice anesthetized with urethane. On- and off-responses in the primary visual cortex were elicited by visual stimuli. Fluorescence responses and field potentials elicited by grating patterns decreased similarly as contrasts of visual stimuli were reduced. Fluorescence responses also decreased as spatial frequency of grating stimuli increased. Compared with intrinsic signal imaging in the same mice, fluorescence imaging showed faster responses with approximately 10 times larger signal changes. Retinotopic maps in the primary visual cortex and area LM were constructed using fluorescence imaging. After monocular deprivation (MD) of 4 d starting from postnatal day 28 (P28), deprived eye responses were suppressed compared with nondeprived eye responses in the binocular zone but not in the monocular zone. Imaging faithfully recapitulated a critical period for plasticity with maximal effects of MD observed around P28 and not in adulthood even under urethane anesthesia. Visual responses were compared before and after MD in the same mice, in which the skull was covered with clear acrylic dental resin. Deprived eye responses decreased after MD, whereas nondeprived eye responses increased. Effects of MD during a critical period were tested 2 weeks after reopening of the deprived eye. Significant ocular dominance plasticity was observed in responses elicited by moving grating patterns, but no long-lasting effect was found in visual responses elicited by light-emitting diode light stimuli. The present results indicate that transcranial flavoprotein fluorescence imaging is a powerful tool for investigating experience-dependent plasticity in the mouse visual cortex.

Minocycline restores cognitive-relative altered proteins in young bile duct-ligated rat prefrontal cortex.

PubMed

Li, Shih-Wen; Chen, Yu-Chieh; Sheen, Jiunn-Ming; Hsu, Mei-Hsin; Tain, You-Lin; Chang, Kow-Aung; Huang, Li-Tung

2017-07-01

Bile duct ligation (BDL) model is used to study hepatic encephalopathy accompanied by cognitive impairment. We employed the proteomic analysis approach to evaluate cognition-related proteins in the prefrontal cortex of young BDL rats and analyzed the effect of minocycline on these proteins and spatial memory. BDL was induced in young rats at postnatal day 17. Minocycline as a slow-release pellet was implanted into the peritoneum. Morris water maze test and two-dimensional liquid chromatography-tandem mass spectrometry were used to evaluate spatial memory and prefrontal cortex protein expression, respectively. We used 2D/LC-MS/MS to analyze for affected proteins in the prefrontal cortex of young BDL rats. Results were verified with Western blotting, immunohistochemistry, and quantitative real-time PCR. The effect of minocycline in BDL rats was assessed. BDL induced spatial deficits, while minocycline rescued it. Collapsin response mediator protein 2 (CRMP2) and manganese-dependent superoxide dismutase (MnSOD) were upregulated and nucleoside diphosphate kinase B (NME2) was downregulated in young BDL rats. BDL rats exhibited decreased levels of brain-derived neurotrophic factor (BDNF) mRNA as compared with those by the control. However, minocycline treatment restored CRMP2 and NME2 protein expression, BDNF mRNA level, and MnSOD activity to control levels. We demonstrated that BDL altered the expression of CRMP2, NME2, MnSOD, and BDNF in the prefrontal cortex of young BDL rats. However, minocycline treatment restored the expression of the affected mediators that are implicated in cognition. Copyright © 2017 Elsevier Inc. All rights reserved.

HOW SHOULD THE WELFARE OF FETAL AND NEUROLOGICALLY IMMATURE POSTNATAL ANIMALS BE PROTECTED?

PubMed Central

Campbell, Madeleine L.H.; Mellor, David J.; Sandøe, Peter

2016-01-01

Legal protection of the welfare of prenatal animals has not previously been addressed as a discrete subject within the academic literature on animal welfare, ethics and law. This paper aims to rectify this by reviewing the protections (or absence of protections) provided for fetuses by existing legislation in various jurisdictions, and considering the extent to which legal protection of animal fetuses can be justified on animal welfare grounds. Questions related to the need to protect the welfare of neurologically immature postnatal animals are also considered. We argue that there are reasons to protect animal fetuses, both in order to protect fetuses themselves against possible suffering, and in order to protect the animals which fetuses will become against negative welfare impacts that originate prenatally. We review the science on whether fetuses can suffer, and argue that extant regulations do not fully reflect current scientific understanding. Following the precautionary principle, we further argue that regulators should consider the possibility that foetuses and neurologically immature postnatal animals may suffer due to subcortically based ‘raw basic affects’ (i.e. relatively undifferentiated experiences of discomfort suggested to be generated by neural processing at levels below the cerebral cortex). Furthermore we show that there are reasons for affording fetuses protection in order to safeguard the long-term welfare of future animals. However, it may be possible to provide such protection via rules or laws relating to the use of certain techniques and the management of pregnant animals, rather than via direct legal protection of fetuses themselves. In order to provide such protection effectively we need to know more about the relationship between maternal nutrition, stress, exercise, management and fetal health, and about the impact of the timing of a fetal insult on long-term postnatal welfare. PMID:26973382

Prenatal ethanol exposure modifies locomotor activity and induces selective changes in Met-enk expression in adolescent rats.

PubMed

Abate, P; Reyes-Guzmán, A C; Hernández-Fonseca, K; Méndez, M

2017-04-01

Several studies suggest that prenatal ethanol exposure (PEE) facilitates ethanol intake. Opioid peptides play a main role in ethanol reinforcement during infancy and adulthood. However, PEE effects upon motor responsiveness elicited by an ethanol challenge and the participation of opioids in these actions remain to be understood. This work assessed the susceptibility of adolescent rats to prenatal and/or postnatal ethanol exposure in terms of behavioral responses, as well as alcohol effects on Met-enk expression in brain areas related to drug reinforcement. Motor parameters (horizontal locomotion, rearings and stereotyped behaviors) in pre- and postnatally ethanol-challenged adolescents were evaluated. Pregnant rats received ethanol (2g/kg) or water during gestational days 17-20. Adolescents at postnatal day 30 (PD30) were tested in a three-trial activity paradigm (habituation, vehicle and drug sessions). Met-enk content was quantitated by radioimmunoassay in several regions: ventral tegmental area [VTA], nucleus accumbens [NAcc], prefrontal cortex [PFC], substantia nigra [SN], caudate-putamen [CP], amygdala, hypothalamus and hippocampus. PEE significantly reduced rearing responses. Ethanol challenge at PD30 decreased horizontal locomotion and showed a tendency to reduce rearings and stereotyped behaviors. PEE increased Met-enk content in the PFC, CP, hypothalamus and hippocampus, but did not alter peptide levels in the amygdala, VTA and NAcc. These findings suggest that PEE selectively modifies behavioral parameters at PD30 and induces specific changes in Met-enk content in regions of the mesocortical and nigrostriatal pathways, the hypothalamus and hippocampus. Prenatal and postnatal ethanol actions on motor activity in adolescents could involve activation of specific neural enkephalinergic pathways. Copyright © 2016 Elsevier Ltd. All rights reserved.

Neuroimaging findings associated with congenital Zika virus syndrome: case series at the time of first epidemic outbreak in Pernambuco State, Brazil.

PubMed

Pires, Pedro; Jungmann, Patricia; Galvão, Jully Moura; Hazin, Adriano; Menezes, Luiza; Ximenes, Ricardo; Tonni, Gabriele; Araujo Júnior, Edward

2018-05-01

This study aimed to describe the prenatal and postnatal neuroimaging and clinical findings in a clinical series following congenital Zika virus syndrome during the first epidemic Zika virus (ZIKV) outbreak in the State of Pernambuco, Brazil. We (the authors) conducted a retrospective study of a prospectively collected case series of fetuses and neonates with microcephaly born to mothers with presumed/confirmed congenital ZIKV syndrome. Prenatal ultrasound findings were reviewed to identify potential central nervous system (CNS) abnormalities. Neonates underwent postnatal neuroimaging follow up by computed tomography (CT)-scan or magnetic resonance (MR) imaging. The prenatal and postnatal outcomes of eight fetuses/neonates born to mothers with presumed/confirmed congenital ZIKV syndrome were examined. The mean gestational age at ultrasound was 31.3 weeks. Severe microcephaly was identified in seven fetuses (87.5%), while ventriculomegaly and brain calcifications were detected in all fetuses. The mean gestational age at delivery and head circumference were 38 weeks and 30.2 cm, respectively. All cases of microcephaly but one was confirmed postnatally. Brain CT scans or MRIs were performed in seven newborns, and all had periventricular and/or parenchymal calcifications, symmetrical or asymmetrical ventriculomegaly, pachygyria, and reduced sulcation and gyration. MR imaging aided the detection of one undetected case of corpus callosum dysgenesis and was essential in documenting reduced mantel of the cerebral cortex and reduced gyration and sulcation, especially involving the parietal lobe. In addition, MR imaging was also able to display irregular interfaces with the subcortical white matter, a finding consistent with polymicrogyria, more frequently seen at the level of the frontal lobe and atrophic and thinned pons. Severe microcephaly and CNS abnormalities may be associated with congenital ZIKV syndrome.

Perinatal methadone exposure produces physical dependence and altered behavioral development in the rat.

PubMed

Kunko, P M; Smith, J A; Wallace, M J; Maher, J R; Saady, J J; Robinson, S E

1996-06-01

Pregnant rats were implanted with osmotic minipumps containing either methadone hydrochloride (9 mg/kg/day) or sterile water. Their offspring were cross-fostered so that the following prenatal/postnatal exposure groups were obtained: water/water, methadone/water, water/methadone and methadone/methadone. Methadone slightly reduced litter size, particularly the number of male offspring, and reduced litter birth weight. The induction or maintenance of physical dependence in the postnatal methadone exposure groups was confirmed by an experiment in which PD19 pups were challenged with naloxone (1 mg/kg, s.c.). Methadone concentrations were assayed in pup brain on postnatal days 4, 10 and 22. Postnatal exposure to methadone via maternal milk produced measurable levels of methadone which decreased with age. Neuromuscular and physical development were assessed. Exposure to methadone accelerated acquisition of the righting reflex, but tended to delay the acquisition of the negative geotaxic response. Postnatal exposure to methadone was associated with decreased somatic growth as measured through postnatal day 21. The older pups (postnatal day 21) exposed to methadone exhibited variations in activity levels: pups exposed to methadone both prenatally and postnatally exhibited the least amount of spontaneous locomotor activity and pups exposed only postnatally exhibited the most activity. Therefore, it is possible to induce and/or maintain physical dependence via lactation in rat pups fostered to methadone-treated dams. Perinatal exposure to methadone by this route produces several subtle disruptions of pup development in the absence of gross maternal or fetal toxicity.

Synapsin-dependent development of glutamatergic synaptic vesicles and presynaptic plasticity in postnatal mouse brain.

PubMed

Bogen, I L; Jensen, V; Hvalby, O; Walaas, S I

2009-01-12

Inactivation of the genes encoding the neuronal, synaptic vesicle-associated proteins synapsin I and II leads to severe reductions in the number of synaptic vesicles in the CNS. We here define the postnatal developmental period during which the synapsin I and/or II proteins modulate synaptic vesicle number and function in excitatory glutamatergic synapses in mouse brain. In wild-type mice, brain levels of both synapsin I and synapsin IIb showed developmental increases during synaptogenesis from postnatal days 5-20, while synapsin IIa showed a protracted increase during postnatal days 20-30. The vesicular glutamate transporters (VGLUT) 1 and VGLUT2 showed synapsin-independent development during postnatal days 5-10, following which significant reductions were seen when synapsin-deficient brains were compared with wild-type brains following postnatal day 20. A similar, synapsin-dependent developmental profile of vesicular glutamate uptake occurred during the same age periods. Physiological analysis of the development of excitatory glutamatergic synapses, performed in the CA1 stratum radiatum of the hippocampus from the two genotypes, showed that both the synapsin-dependent part of the frequency facilitation and the synapsin-dependent delayed response enhancement were restricted to the period after postnatal day 10. Our data demonstrate that while both synaptic vesicle number and presynaptic short-term plasticity are essentially independent of synapsin I and II prior to postnatal day 10, maturation and function of excitatory synapses appear to be strongly dependent on synapsin I and II from postnatal day 20.

Postnatal penile growth concurrent with mini-puberty predicts later sex-typed play behavior: Evidence for neurobehavioral effects of the postnatal androgen surge in typically developing boys.

PubMed

Pasterski, Vickie; Acerini, Carlo L; Dunger, David B; Ong, Ken K; Hughes, Ieuan A; Thankamony, Ajay; Hines, Melissa

2015-03-01

The masculinizing effects of prenatal androgens on human neurobehavioral development are well established. Also, the early postnatal surge of androgens in male infants, or mini-puberty, has been well documented and is known to influence physiological development, including penile growth. However, neurobehavioral effects of androgen exposure during mini-puberty are largely unknown. The main aim of the current study was to evaluate possible neurobehavioral consequences of mini-puberty by relating penile growth in the early postnatal period to subsequent behavior. Using multiple linear regression, we demonstrated that penile growth between birth and three months postnatal, concurrent with mini-puberty, significantly predicted increased masculine/decreased feminine behavior assessed using the Pre-school Activities Inventory (PSAI) in 81 healthy boys at 3 to 4years of age. When we controlled for other potential influences on masculine/feminine behavior and/or penile growth, including variance in androgen exposure prenatally and body growth postnally, the predictive value of penile growth in the early postnatal period persisted. More specifically, prenatal androgen exposure, reflected in the measurement of anogenital distance (AGD), and early postnatal androgen exposure, reflected in penile growth from birth to 3months, were significant predictors of increased masculine/decreased feminine behavior, with each accounting for unique variance. Our findings suggest that independent associations of PSAI with AGD at birth and with penile growth during mini-puberty reflect prenatal and early postnatal androgen exposures respectively. Thus, we provide a novel and readily available approach for assessing effects of early androgen exposures, as well as novel evidence that early postnatal aes human neurobehavioral development. Copyright © 2015. Published by Elsevier Inc.

p57KIP2 regulates radial glia and intermediate precursor cell cycle dynamics and lower layer neurogenesis in developing cerebral cortex

PubMed Central

Mairet-Coello, Georges; Tury, Anna; Van Buskirk, Elise; Robinson, Kelsey; Genestine, Matthieu; DiCicco-Bloom, Emanuel

2012-01-01

During cerebral cortex development, precise control of precursor cell cycle length and cell cycle exit is required for balanced precursor pool expansion and layer-specific neurogenesis. Here, we defined the roles of cyclin-dependent kinase inhibitor (CKI) p57KIP2, an important regulator of G1 phase, using deletion mutant mice. Mutant mice displayed macroencephaly associated with cortical hyperplasia during late embryogenesis and postnatal development. Embryonically, proliferation of radial glial cells (RGC) and intermediate precursors (IPC) was increased, expanding both populations, with greater effect on IPCs. Furthermore, cell cycle re-entry was increased during early corticogenesis, whereas cell cycle exit was augmented at middle stage. Consequently, neurogenesis was reduced early, whereas it was enhanced during later development. In agreement, the timetable of early neurogenesis, indicated by birthdating analysis, was delayed. Cell cycle dynamics analyses in mutants indicated that p57KIP2 regulates cell cycle length in both RGCs and IPCs. By contrast, related CKI p27KIP1 controlled IPC proliferation exclusively. Furthermore, p57KIP2 deficiency markedly increased RGC and IPC divisions at E14.5, whereas p27KIP1 increased IPC proliferation at E16.5. Consequently, loss of p57KIP2 increased primarily layer 5-6 neuron production, whereas loss of p27KIP1 increased neurons specifically in layers 2-5. In conclusion, our observations suggest that p57KIP2 and p27KIP1 control neuronal output for distinct cortical layers by regulating different stages of precursor proliferation, and support a model in which IPCs contribute to both lower and upper layer neuron generation. PMID:22223678

Glutamate Neonatal Excitotoxicity Modifies VEGF-A, VEGF-B, VEGFR-1 and VEGFR-2 Protein Expression Profiles During Postnatal Development of the Cerebral Cortex and Hippocampus of Male Rats.

PubMed

Castañeda-Cabral, Jose Luis; Beas-Zarate, Carlos; Gudiño-Cabrera, Graciela; Ureña-Guerrero, Monica E

2017-09-01

Vascular endothelial growth factor (VEGF) exerts both neuroprotective and proinflammatory effects in the brain, depending on the VEGF (A-E) and VEGF receptor (VEGFR1-3) types involved. Neonatal monosodium glutamate (MSG) treatment triggers an excitotoxic degenerative process associated with several neuropathological conditions, and VEGF messenger RNA (mRNA) expression is increased at postnatal day (PD) 14 in rat hippocampus (Hp) following the treatment. The aim of this work was to establish the changes in immunoreactivity to VEGF-A, VEGF-B, VEGFR-1 and VEGFR-2 proteins induced by neonatal MSG treatment (4 g/kg, subcutaneous, at PD1, 3, 5 and 7) in the cerebral motor cortex (CMC) and Hp. Samples collected from PD2 to PD60 from control and MSG-treated male Wistar rats were assessed by western blotting for each protein. Considering that immunoreactivity measured by western blotting is related to the protein expression level, we found that each protein in each cerebral region has a specific expression profile throughout the studied ages, and all profiles were differentially modified by MSG. Specifically, neonatal MSG treatment significantly increased the immunoreactivity to the following: (1) VEGF-A at PD8-PD10 in the CMC and at PD6-PD8 in the Hp; (2) VEGF-B at PD2, PD6 and PD10 in the CMC and at PD8-PD9 in the Hp; and (3) VEGFR-2 at PD6-PD8 in the CMC and at PD21-PD60 in the Hp. Also, MSG significantly reduced the immunoreactivity to the following: (1) VEGF-B at PD8-PD9 and PD45-PD60 in the CMC; and (2) VEGFR-1 at PD4-PD6 and PD14-PD21 in the CMC and at PD4, PD9-PD10 and PD60 in the Hp. Our results indicate that VEGF-mediated signalling is involved in the excitotoxic process triggered by neonatal MSG treatment and should be further characterized.

Cerebellar cortex development in the weaver condition presents regional and age-dependent abnormalities without differences in Purkinje cells neurogenesis.

PubMed

Martí, Joaquín; Santa-Cruz, María C; Hervás, José P; Bayer, Shirley A; Villegas, Sandra

2016-01-01

Ataxias are neurological disorders associated with the degeneration of Purkinje cells (PCs). Homozygous weaver mice (wv/wv) have been proposed as a model for hereditary cerebellar ataxia because they present motor abnormalities and PC loss. To ascertain the physiopathology of the weaver condition, the development of the cerebellar cortex lobes was examined at postnatal day (P): P8, P20 and P90. Three approaches were used: 1) quantitative determination of several cerebellar features; 2) qualitative evaluation of the developmental changes occurring in the cortical lobes; and 3) autoradiographic analyses of PC generation and placement. Our results revealed a reduction in the size of the wv/wv cerebellum as a whole, confirming previous results. However, as distinguished from these reports, we observed that quantified parameters contribute differently to the abnormal growth of the wv/wv cerebellar lobes. Qualitative analysis showed anomalies in wv/wv cerebellar cytoarchitecture, depending on the age and lobe analyzed. Such abnormalities included the presence of the external granular layer after P20 and, at P90, ectopic cells located in the molecular layer following several placement patterns. Finally, we obtained autoradiographic evidence that wild-type and wv/wv PCs presented similar neurogenetic timetables, as reported. However, the innovative character of this current work lies in the fact that the neurogenetic gradients of wv/wv PCs were not modified from P8 to P90. A tendency for the accumulation of late-formed PCs in the anterior and posterior lobes was found, whereas early-generated PCs were concentrated in the central and inferior lobes. These data suggested that wv/wv PCs may migrate properly to their final destinations. The extrapolation of our results to patients affected with cerebellar ataxias suggests that all cerebellar cortex lobes are affected with several age-dependent alterations in cytoarchitectonics. We also propose that PC loss may be regionally variable and not related to their neurogenetic timetables.

Combined prenatal and postnatal butyl paraben exposure produces autism-like symptoms in offspring: comparison with valproic acid autistic model.

PubMed

Ali, Elham H A; Elgoly, Amany H Mahmoud

2013-10-01

The aim of this work is to evaluate the impact of butyl paraben (BP) in brain of the pups developed for mothers administered BP from early pregnancy till weaning and its effect on studying the behavior, brain neurotransmitters and brain derived neurotrophic factor BDNF via comparing the results with valproic acid (VA) autistic-rat model preparing by a single oral injection dose of VA (800 mg/kg b.wt) at the 12.5 days of gestation. Butyl paraben was orally and subcutaneously administered (200 mg/kg b.wt) to pregnant rats from gestation day 1 to lactation day 21. The offspring male rats were subjected at the last 3 days of lactation to Morris water maze and three chamber sociability test then decapitated and the brain was excised and dissected to the cortex, hippocampus, cerebellum, midbrain and pons for the determination of norepinephrine, dopamine and serotonin (NE, DA and 5-HT) and cortex amino acids and whole brain BDNF. The results showed similar social and learning and memory behavioral deficits in VA rat model and the butyl paraben offspring in comparison with the controls. Also, some similar alterations were observed in monoamine content, amino acids and BDNF factor in the autistic-like model and butyl paraben offspring in comparison with the controls. The alterations were recorded notably in hippocampus and pons NE, midbrain DA, hippocampus and midbrain 5-HT, and frontal cortex GABA and asparagine. These data suggest that prenatal exposure to butyl paraben induced neuro-developmental disorders similar to some of the neurodevelopmental disorders observed in the VA model of autism. © 2013 Elsevier Inc. All rights reserved.

Apoptotic signaling pathways induced by acute administration of branched-chain amino acids in an animal model of maple syrup urine disease.

PubMed

Vilela, Thais C; Scaini, Giselli; Furlanetto, Camila B; Pasquali, Matheus A B; Santos, João Paulo A; Gelain, Daniel P; Moreira, José Cláudio F; Schuck, Patrícia F; Ferreira, Gustavo C; Streck, Emilio L

2017-02-01

Maple Syrup Urine Disease (MSUD) is an inborn error of metabolism caused by a deficiency of the branched-chain α-keto acid dehydrogenase complex activity. This blockage leads to accumulation of the branched-chain amino acids leucine, isoleucine and valine, as well as their corresponding α-keto acids and α-hydroxy acids. The affected patients present severe neurological symptoms, such as coma and seizures, as well as edema and cerebral atrophy. Considering that the mechanisms of the neurological symptoms presented by MSUD patients are still poorly understood, in this study, protein levels of apoptotic factors are measured, such as Bcl-2, Bcl-xL, Bax, caspase-3 and -8 in hippocampus and cerebral cortex of rats submitted to acute administration of branched-chain amino acids during their development. The results in this study demonstrated that BCAA acute exposure during the early postnatal period did not significantly change Bcl-2, Bcl-xL, Bax and caspase-8 protein levels. However, the Bax/Bcl-2 ratio and procaspase-3 protein levels were decreased in hippocampus. On the other hand, acute administration of BCAA in 30-day-old rats increase in Bax/Bcl-2 ratio followed by an increased caspase-3 activity in cerebral cortex, whereas BCAA induces apoptosis in hippocampus through activation and cleavage of caspase-3 and -8 without changing the Bax/Bcl-2 ratio. In conclusion, the results suggest that apoptosis could be of pivotal importance in the developmental neurotoxic effects of BCAA. In addition, the current studies also suggest that multiple mechanisms may be involved in BCAA-induced apoptosis in the cerebral cortex and hippocampus.

Genetic control of postnatal human brain growth

PubMed Central

van Dyck, Laura I.; Morrow, Eric M.

2017-01-01

Purpose of review Studies investigating postnatal brain growth disorders inform the biology underlying the development of human brain circuitry. This research is becoming increasingly important for the diagnosis and treatment of childhood neurodevelopmental disorders, including autism and related disorders. Here we review recent research on typical and abnormal postnatal brain growth and examine potential biological mechanisms. Recent findings Clinically, brain growth disorders are heralded by diverging head size for a given age and sex, but are more precisely characterized by brain imaging, postmortem analysis, and animal model studies. Recent neuroimaging and molecular biological studies on postnatal brain growth disorders have broadened our view of both typical and pathological postnatal neurodevelopment. Correlating gene and protein function with brain growth trajectories uncovers postnatal biological mechanisms, including neuronal arborization, synaptogenesis and pruning, and gliogenesis and myelination. Recent investigations of childhood neurodevelopmental and neurodegenerative disorders highlight the underlying genetic programming and experience-dependent remodeling of neural circuitry. Summary In order to understand typical and abnormal postnatal brain development, clinicians and researchers should characterize brain growth trajectories in the context of neurogenetic syndromes. Understanding mechanisms and trajectories of postnatal brain growth will aid in differentiating, diagnosing, and potentially treating neurodevelopmental disorders. PMID:27898583

Early detection and treatment of postnatal depression in primary care.

PubMed

Davies, Bronwen R; Howells, Sarah; Jenkins, Meryl

2003-11-01

Postnatal depression has a relatively high incidence and gives rise to considerable morbidity. There is sound evidence supporting the use of the Edinburgh Postnatal Depression Scale as a screening tool for possible postnatal depression. This paper reports on a project developed by two health visitors and a community mental health nurse working in the United Kingdom. The aim of the project was to improve the early detection and treatment of postnatal depression in the population of the general practice to which they were attached. The health visitors screened for postnatal depression in the course of routine visits on four occasions during the first postpartum year. Women identified as likely to be suffering from postnatal depression were offered 'listening visits' as a first-line intervention, with referral on to the general practitioner and/or community mental health nurse if indicated. Data collected over 3 years showed that the project succeeded in its aim of enhancing early detection and treatment of postnatal depression. These findings replicate those of other studies. The data also showed that a substantial number of women were identified for the first time as likely to be suffering from postnatal depression at 12 months postpartum. Women screened for the first time at 12 months were at greater risk than those who had been screened earlier than this. Health visitors should screen for postnatal depression throughout the period of their contact with mothers, not solely in the immediate postnatal period. It is particularly important to screen women who, for whatever reason, were not screened when their child was younger. The knowledge and skills needed to use the Edinburgh Postnatal Depression Scale and provide first-line intervention and onward referral can be developed at practitioner level through close collaborative working.

Development of coherent neuronal activity patterns in mammalian cortical networks: common principles and local hetereogeneity.

PubMed

Egorov, Alexei V; Draguhn, Andreas

2013-01-01

Many mammals are born in a very immature state and develop their rich repertoire of behavioral and cognitive functions postnatally. This development goes in parallel with changes in the anatomical and functional organization of cortical structures which are involved in most complex activities. The emerging spatiotemporal activity patterns in multi-neuronal cortical networks may indeed form a direct neuronal correlate of systemic functions like perception, sensorimotor integration, decision making or memory formation. During recent years, several studies--mostly in rodents--have shed light on the ontogenesis of such highly organized patterns of network activity. While each local network has its own peculiar properties, some general rules can be derived. We therefore review and compare data from the developing hippocampus, neocortex and--as an intermediate region--entorhinal cortex. All cortices seem to follow a characteristic sequence starting with uncorrelated activity in uncoupled single neurons where transient activity seems to have mostly trophic effects. In rodents, before and shortly after birth, cortical networks develop weakly coordinated multineuronal discharges which have been termed synchronous plateau assemblies (SPAs). While these patterns rely mostly on electrical coupling by gap junctions, the subsequent increase in number and maturation of chemical synapses leads to the generation of large-scale coherent discharges. These patterns have been termed giant depolarizing potentials (GDPs) for predominantly GABA-induced events or early network oscillations (ENOs) for mostly glutamatergic bursts, respectively. During the third to fourth postnatal week, cortical areas reach their final activity patterns with distinct network oscillations and highly specific neuronal discharge sequences which support adult behavior. While some of the mechanisms underlying maturation of network activity have been elucidated much work remains to be done in order to fully understand the rules governing transition from immature to mature patterns of network activity. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

The neuroprotective effects of MK-801 on the induction of microgyria by freezing injury to the newborn rat neocortex.

PubMed

Rosen, G D; Sigel, E A; Sherman, G F; Galaburda, A M

1995-11-01

Four-layered microgyria is associated with many developmental disorders, including mental retardation, epilepsy, and developmental dyslexia. Freezing lesions to the newborn rodent neocortex result in the formation of four-layered microgyria. Previous research had suggested this type of injury acts as an hypoxic/ischemic event to the developing cortical plate. The current study examines the effectiveness of the non-competitive N-methyl-D-aspartate receptor antagonist dizocilpine (MK-801) in protecting against freezing injury to the newborn rat cortical plate. Three groups of rats received freezing injury to the cortical plate on the first day of life (postnatal day 1). Two groups were treated with MK-801 (1 or 2 mg/kg) 0.5 h before the lesion and 6 and 14 h after, while one group received saline injections. A fourth group received MK-801 injections, but did not have a freezing lesion. The volume of neocortical abnormality was determined for all three groups in rats killed after postnatal day 7. Treatment with the higher dose of MK-801 (3 x 2 mg/kg) dramatically reduced the effects of freezing injury but also resulted in over 50% mortality in both lesioned and unlesioned groups. Animals in the lesioned group, however, had a decreased volume of abnormal cortex, and there were fewer animals with microsulci than in the untreated group. This is the first demonstration of a significant anatomical neuroprotective effect in newborns leading to a reduction of cortical malformation.

Early-Life Seizures Produce Lasting Alterations in the Structure and Function of the Prefrontal Cortex

PubMed Central

Kleen, Jonathan K.; Sesqué, Alexandre; Wu, Edie X.; Miller, Forrest A.; Hernan, Amanda E.; Holmes, Gregory L.; Scott, Rod C.

2011-01-01

Early-life seizures (ELS) are associated with long-term behavioral disorders including autism and ADHD, suggesting that frontal lobe structures may be permanently affected. We tested whether ELS produce structural alterations in the prefrontal cortex (PFC) and impair PFC-mediated function using an operant task of behavioral flexibility in rats. Adult rats that had been exposed to 75 flurothyl seizures during postnatal days 1–10 showed decreased behavioral flexibility in the task compared to controls over multiple behavioral sessions, measured as a lever preference asymmetry (p<0.001) and a decreased efficiency of attaining food rewards (p<0.05). ELS rats also showed an increased thickness of the PFC (p<0.01), primarily attributed to layer V (p<0.01) with no differences in cell density. These structural changes correlated with lever preference behavioral impairments (p<0.05). This study demonstrates that the consequences of ELS extend to the PFC, which may help explain the high prevalence of comorbid behavioral disorders following ELS. PMID:21873119

A simpler primate brain: the visual system of the marmoset monkey

PubMed Central

Solomon, Samuel G.; Rosa, Marcello G. P.

2014-01-01

Humans are diurnal primates with high visual acuity at the center of gaze. Although primates share many similarities in the organization of their visual centers with other mammals, and even other species of vertebrates, their visual pathways also show unique features, particularly with respect to the organization of the cerebral cortex. Therefore, in order to understand some aspects of human visual function, we need to study non-human primate brains. Which species is the most appropriate model? Macaque monkeys, the most widely used non-human primates, are not an optimal choice in many practical respects. For example, much of the macaque cerebral cortex is buried within sulci, and is therefore inaccessible to many imaging techniques, and the postnatal development and lifespan of macaques are prohibitively long for many studies of brain maturation, plasticity, and aging. In these and several other respects the marmoset, a small New World monkey, represents a more appropriate choice. Here we review the visual pathways of the marmoset, highlighting recent work that brings these advantages into focus, and identify where additional work needs to be done to link marmoset brain organization to that of macaques and humans. We will argue that the marmoset monkey provides a good subject for studies of a complex visual system, which will likely allow an important bridge linking experiments in animal models to humans. PMID:25152716

Long-term increase in coherence between the basal ganglia and motor cortex after asphyxial cardiac arrest and resuscitation in developing rats.

PubMed

Aravamuthan, Bhooma R; Shoykhet, Michael

2015-10-01

The basal ganglia are vulnerable to injury during cardiac arrest. Movement disorders are a common morbidity in survivors. Yet, neuronal motor network changes post-arrest remain poorly understood. We compared function of the motor network in adult rats that, during postnatal week 3, underwent 9.5 min of asphyxial cardiac arrest (n = 9) or sham intervention (n = 8). Six months after injury, we simultaneously recorded local field potentials (LFP) from the primary motor cortex (MCx) and single neuron firing and LFP from the rat entopeduncular nucleus (EPN), which corresponds to the primate globus pallidus pars interna. Data were analyzed for firing rates, power, and coherence between MCx and EPN spike and LFP activity. Cardiac arrest survivors display chronic motor deficits. EPN firing rate is lower in cardiac arrest survivors (19.5 ± 2.4 Hz) compared with controls (27.4 ± 2.7 Hz; P < 0.05). Cardiac arrest survivors also demonstrate greater coherence between EPN single neurons and MCx LFP (3-100 Hz; P < 0.001). This increased coherence indicates abnormal synchrony in the neuronal motor network after cardiac arrest. Increased motor network synchrony is thought to be antikinetic in primary movement disorders. Characterization of motor network synchrony after cardiac arrest may help guide management of post-hypoxic movement disorders.

Spectrotemporal dynamics of auditory cortical synaptic receptive field plasticity.

PubMed

Froemke, Robert C; Martins, Ana Raquel O

2011-09-01

The nervous system must dynamically represent sensory information in order for animals to perceive and operate within a complex, changing environment. Receptive field plasticity in the auditory cortex allows cortical networks to organize around salient features of the sensory environment during postnatal development, and then subsequently refine these representations depending on behavioral context later in life. Here we review the major features of auditory cortical receptive field plasticity in young and adult animals, focusing on modifications to frequency tuning of synaptic inputs. Alteration in the patterns of acoustic input, including sensory deprivation and tonal exposure, leads to rapid adjustments of excitatory and inhibitory strengths that collectively determine the suprathreshold tuning curves of cortical neurons. Long-term cortical plasticity also requires co-activation of subcortical neuromodulatory control nuclei such as the cholinergic nucleus basalis, particularly in adults. Regardless of developmental stage, regulation of inhibition seems to be a general mechanism by which changes in sensory experience and neuromodulatory state can remodel cortical receptive fields. We discuss recent findings suggesting that the microdynamics of synaptic receptive field plasticity unfold as a multi-phase set of distinct phenomena, initiated by disrupting the balance between excitation and inhibition, and eventually leading to wide-scale changes to many synapses throughout the cortex. These changes are coordinated to enhance the representations of newly-significant stimuli, possibly for improved signal processing and language learning in humans. Copyright © 2011 Elsevier B.V. All rights reserved.

Spectrotemporal Dynamics of Auditory Cortical Synaptic Receptive Field Plasticity

PubMed Central

Froemke, Robert C.; Martins, Ana Raquel O.

2011-01-01

The nervous system must dynamically represent sensory information in order for animals to perceive and operate within a complex, changing environment. Receptive field plasticity in the auditory cortex allows cortical networks to organize around salient features of the sensory environment during postnatal development, and then subsequently refine these representations depending on behavioral context later in life. Here we review the major features of auditory cortical receptive field plasticity in young and adult animals, focusing on modifications to frequency tuning of synaptic inputs. Alteration in the patterns of acoustic input, including sensory deprivation and tonal exposure, leads to rapid adjustments of excitatory and inhibitory strengths that collectively determine the suprathreshold tuning curves of cortical neurons. Long-term cortical plasticity also requires co-activation of subcortical neuromodulatory control nuclei such as the cholinergic nucleus basalis, particularly in adults. Regardless of developmental stage, regulation of inhibition seems to be a general mechanism by which changes in sensory experience and neuromodulatory state can remodel cortical receptive fields. We discuss recent findings suggesting that the microdynamics of synaptic receptive field plasticity unfold as a multi-phase set of distinct phenomena, initiated by disrupting the balance between excitation and inhibition, and eventually leading to wide-scale changes to many synapses throughout the cortex. These changes are coordinated to enhance the representations of newly-significant stimuli, possibly for improved signal processing and language learning in humans. PMID:21426927

Perinatal exposure to lead (Pb) induces ultrastructural and molecular alterations in synapses of rat offspring.

PubMed

Gąssowska, Magdalena; Baranowska-Bosiacka, Irena; Moczydłowska, Joanna; Frontczak-Baniewicz, Małgorzata; Gewartowska, Magdalena; Strużyńska, Lidia; Gutowska, Izabela; Chlubek, Dariusz; Adamczyk, Agata

2016-12-12

Lead (Pb), environmentally abundant heavy-metal pollutant, is a strong toxicant for the developing central nervous system. Pb intoxication in children, even at low doses, is found to affect learning and memorizing, with devastating effects on cognitive function and intellectual development. However, the precise mechanism by which Pb impairs synaptic plasticity is not fully elucidated. The purpose of this study was to investigate the effect of pre- and neonatal exposure to low dose of Pb (with Pb concentrations in whole blood below 10μg/dL) on the synaptic structure and the pre- and postsynaptic proteins expression in the developing rat brain. Furthermore, the level of brain-derived neurotrophic factor (BDNF) was analyzed. Pregnant female Wistar rats received 0.1% lead acetate (PbAc) in drinking water from the first day of gestation until weaning of the offspring, while the control animals received drinking water. During the feeding of pups, mothers from the Pb-group were continuously receiving PbAc. Pups of both groups were weaned at postnatal day 21 and then until postnatal day 28 received only drinking water. 28-day old pups were sacrificed and the ultrastructural changes as well as expression of presynaptic (VAMP1/2, synaptophysin, synaptotagmin-1, SNAP25, syntaxin-1) and postsynaptic (PSD-95) proteins were analyzed in: forebrain cortex, cerebellum and hippocampus. Our data revealed that pre- and neonatal exposure to low dose of Pb promotes pathological changes in synapses, including nerve endings swelling, blurred and thickened synaptic cleft structure as well as enhanced density of synaptic vesicles in the presynaptic area. Moreover, synaptic mitochondria were elongated, swollen or shrunken in Pb-treated animals. These structural abnormalities were accompanied by decrease in the level of key synaptic proteins: synaptotagmin-1 in cerebellum, SNAP25 in hippocampus and syntaxin-1 in cerebellum and hippocampus. In turn, increased level of synaptophysin was noticed in the cerebellum, while the expression of postsynaptic PSD-95 was significantly decreased in forebrain cortex and cerebellum, and raised in hippocampus. Additionally, we observed the lower level of BDNF in all brain structures in comparison to control animals. In conclusion, perinatal exposure to low doses of Pb caused pathological changes in nerve endings associated with the alterations in the level of key synaptic proteins. All these changes can lead to synaptic dysfunction, expressed by the impairment of the secretory mechanism and thereby to the abnormalities in neurotransmission as well as to the neuronal dysfunction. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Distribution of ELOVL4 in the Developing and Adult Mouse Brain

PubMed Central

Sherry, David M.; Hopiavuori, Blake R.; Stiles, Megan A.; Rahman, Negar S.; Ozan, Kathryn G.; Deak, Ferenc; Agbaga, Martin-Paul; Anderson, Robert E.

2017-01-01

ELOngation of Very Long chain fatty acids (ELOVL)-4 is essential for the synthesis of very long chain-fatty acids (fatty acids with chain lengths ≥ 28 carbons). The functions of ELOVL4 and its very long-chain fatty acid products are poorly understood at present. However, mutations in ELOVL4 cause neurodevelopmental or neurodegenerative diseases that vary according to the mutation and inheritance pattern. Heterozygous inheritance of different ELOVL4 mutations causes Stargardt-like Macular Dystrophy or Spinocerebellar Ataxia type 34. Homozygous inheritance of ELOVL4 mutations causes more severe disease characterized by seizures, intellectual disability, ichthyosis, and premature death. To better understand ELOVL4 and very long chain fatty acid function in the brain, we examined ELOVL4 expression in the mouse brain between embryonic day 18 and postnatal day 60 by immunolabeling using ELOVL4 and other marker antibodies. ELOVL4 was widely expressed in a region- and cell type-specific manner, and was restricted to cell bodies, consistent with its known localization to endoplasmic reticulum. ELOVL4 labeling was most prominent in gray matter, although labeling also was present in some cells located in white matter. ELOVL4 was widely expressed in the developing brain by embryonic day 18 and was especially pronounced in regions underlying the lateral ventricles and other neurogenic regions. The basal ganglia in particular showed intense ELOVL4 labeling at this stage. In the postnatal brain, cerebral cortex, hippocampus, cerebellum, thalamus, hypothalamus, midbrain, pons, and medulla all showed prominent ELOVL4 labeling, although ELOVL4 distribution was not uniform across all cells or subnuclei within these regions. In contrast, the basal ganglia showed little ELOVL4 labeling in the postnatal brain. Double labeling studies showed that ELOVL4 was primarily expressed by neurons, although presumptive oligodendrocytes located in white matter tracts also showed labeling. Little or no ELOVL4 labeling was present in astrocytes or radial glial cells. These findings suggest that ELOVL4 and its very long chain fatty acid products are important in many parts of the brain and that they are particularly associated with neuronal function. Specific roles for ELOVL4 and its products in oligodendrocytes and myelin and in cellular proliferation, especially during development, are possible. PMID:28507511

Consequences of early life stress on the expression of endocannabinoid-related genes in the rat brain.

PubMed

Marco, Eva M; Echeverry-Alzate, Victor; López-Moreno, Jose Antonio; Giné, Elena; Peñasco, Sara; Viveros, Maria Paz

2014-09-01

The endocannabinoid system is involved in several physiological and pathological states including anxiety, depression, addiction and other neuropsychiatric disorders. Evidence from human and rodent studies suggests that exposure to early life stress may increase the risk of psychopathology later in life. Indeed, maternal deprivation (MD) (24 h at postnatal day 9) in rats induces behavioural alterations associated with depressive-like and psychotic-like symptoms, as well as important changes in the endocannabinoid system. As most neuropsychiatric disorders first appear at adolescence, and show remarkable sexual dimorphisms in their prevalence and severity, in the present study, we analysed the gene expression of the main components of the brain cannabinoid system in adolescent (postnatal day 46) Wistar male and female rats reared under standard conditions or exposed to MD. For this, we analysed, by real-time quantitative PCR, the expression of genes encoding for CB1 and CB2 receptors, TRPV1 and GPR55 (Cnr1, Cnr2a, Cnr2b, Trpv1, and Gpr55), for the major enzymes of synthesis, N-acyl phosphatidyl-ethanolamine phospholipase D (NAPE-PLD) and diacylglycerol lipase (DAGL) (Nape-pld, Dagla and Daglb), and degradation, fatty acid amide hydrolase (FAAH) and monoacylglycerol lipase (MAGL) (Faah, Magl and Cox-2), in specific brain regions, that is, the frontal cortex, ventral and dorsal striatum, dorsal hippocampus and amygdala. In males, MD increased the genetic expression of all the genes studied within the frontal cortex, whereas in females such an increase was observed only in the hippocampus. In conclusion, the endocannabinoid system is sensitive to early life stress at the gene expression level in a sex-dependent and region-dependent manner, and these changes are already evident in the adolescent brain.

Conflicting cultural perspectives: meanings and experiences of postnatal depression among women in Indian communities.

PubMed

Jain, Anita; Levy, David

2013-01-01

A woman's cultural and social context affects her experience of postnatal depression. In this literature review, the authors explore questions regarding normal and abnormal postnatal experiences of Indian women with consideration to cross-cultural perspectives. Although postnatal distress or sadness is recognized among many cultures, it is constructed as a transient state in some cultures and as an illness in others. A major challenge for health care providers in Western countries like the United Kingdom and Australia is to develop culturally sensitive approaches to postnatal care for migrant mothers.

Experimental Evidence that In Vivo Intracerebral Administration of L-2-Hydroxyglutaric Acid to Neonatal Rats Provokes Disruption of Redox Status and Histopathological Abnormalities in the Brain.

PubMed

Ribeiro, Rafael Teixeira; Zanatta, Ângela; Amaral, Alexandre Umpierrez; Leipnitz, Guilhian; de Oliveira, Francine Hehn; Seminotti, Bianca; Wajner, Moacir

2018-04-01

Tissue accumulation of L-2-hydroxyglutaric acid (L-2-HG) is the biochemical hallmark of L-2-hydroxyglutaric aciduria (L-2-HGA), a rare neurometabolic inherited disease characterized by neurological symptoms and brain white matter abnormalities whose pathogenesis is not yet well established. L-2-HG was intracerebrally administered to rat pups at postnatal day 1 (P1) to induce a rise of L-2-HG levels in the central nervous system (CNS). Thereafter, we investigated whether L-2-HG in vivo administration could disturb redox homeostasis and induce brain histopathological alterations in the cerebral cortex and striatum of neonatal rats. L-2-HG markedly induced the generation of reactive oxygen species (increase of 2',7'-dichloroflurescein-DCFH-oxidation), lipid peroxidation (increase of malondialdehyde concentrations), and protein oxidation (increase of carbonyl formation and decrease of sulfhydryl content), besides decreasing the antioxidant defenses (reduced glutathione-GSH) and sulfhydryl content in the cerebral cortex. Alterations of the activities of various antioxidant enzymes were also observed in the cerebral cortex and striatum following L-2-HG administration. Furthermore, L-2-HG-induced lipid peroxidation and GSH decrease in the cerebral cortex were prevented by the antioxidant melatonin and by the classical antagonist of NMDA glutamate receptor MK-801, suggesting the involvement of reactive species and of overstimulation of NMDA receptor in these effects. Finally, L-2-HG provoked significant vacuolation and edema particularly in the cerebral cortex with less intense alterations in the striatum that were possibly associated with the unbalanced redox homeostasis caused by this metabolite. Taken together, it is presumed that these pathomechanisms may underlie the neurological symptoms and brain abnormalities observed in the affected patients.

Transgenic mouse lines for non-invasive ratiometric monitoring of intracellular chloride

PubMed Central

Batti, Laura; Mukhtarov, Marat; Audero, Enrica; Ivanov, Anton; Paolicelli, Rosa Chiara; Zurborg, Sandra; Gross, Cornelius; Bregestovski, Piotr; Heppenstall, Paul A.

2013-01-01

Chloride is the most abundant physiological anion and participates in a variety of cellular processes including trans-epithelial transport, cell volume regulation, and regulation of electrical excitability. The development of tools to monitor intracellular chloride concentration ([Cli]) is therefore important for the evaluation of cellular function in normal and pathological conditions. Recently, several Cl-sensitive genetically encoded probes have been described which allow for non-invasive monitoring of [Cli]. Here we describe two mouse lines expressing a CFP-YFP-based Cl probe called Cl-Sensor. First, we generated transgenic mice expressing Cl-Sensor under the control of the mouse Thy1 mini promoter. Cl-Sensor exhibited good expression from postnatal day two (P2) in neurons of the hippocampus and cortex, and its level increased strongly during development. Using simultaneous whole-cell monitoring of ionic currents and Cl-dependent fluorescence, we determined that the apparent EC50 for Cli was 46 mM, indicating that this line is appropriate for measuring neuronal [Cli] in postnatal mice. We also describe a transgenic mouse reporter line for Cre-dependent conditional expression of Cl-Sensor, which was targeted to the Rosa26 locus and by incorporating a strong exogenous promoter induced robust expression upon Cre-mediated recombination. We demonstrate high levels of tissue-specific expression in two different Cre-driver lines targeting cells of the myeloid lineage and peripheral sensory neurons. Using these mice the apparent EC50 for Cli was estimated to be 61 and 54 mM in macrophages and DRG, respectively. Our data suggest that these mouse lines will be useful models for ratiometric monitoring of Cli in specific cell types in vivo. PMID:23734096

Changes in Gene Expression Profiles in Adult Rat Brain Structures after Neonatal Action of Dipeptidyl Peptidase-IV Inhibitors.

PubMed

Zubkov, Eugene A; Zorkina, Yana A; Orshanskaya, Elena V; Khlebnikova, Nadezhda N; Krupina, Natalia A; Chekhonin, Vladimir P

2017-01-01

Previous studies have shown the development of emotional and motivational disorders, such as anxiety-depression-like disorders with increased aggression in adolescent and adult Wistar rats, occurs after neonatal exposure to the dipeptidyl peptidase-IV (DPP-IV, EC 3.4.14.5) inhibitors diprotin A and sitagliptin (postnatal days 5-18). In this study, using real-time PCR, we evaluated changes in the gene expression of serine protease DPP-IV and prolyl endopeptidase (PREP, EC 3.4.21.26; dpp4 and prep genes), monoamine oxidase А (maoA) and B (maoB), and serotonin transporter (SERT; sert) in the brain structures from 3-month-old rats after postnatal action of DPP-IV inhibitors diprotin A and sitagliptin. Dpp4, sert, and maoB gene expression increased and maoA gene expression changed with a tendency to increase in the striatum of rats with neonatal sitagliptin action. The increase of maoA gene expression was also shown in the amygdala. An increase in prep gene expression was found in the striatum of rats with the neonatal action of diprotin A, and a decrease in maoB gene expression was observed in the amygdala. We detected a significant downward trend in sert gene expression in the frontal cortex and amygdala, as well as a tendency to increase in maoA gene expression in the hypothalamus. These findings suggest that changes in the expression of the abovementioned genes are associated with the development of anxiety and depression, with increased aggression caused by the neonatal action of diprotin A and sitagliptin. © 2018 S. Karger AG, Basel.

Effect of Early-Life Fluoxetine on Anxiety-Like Behaviors in BDNF Val66Met Mice.

PubMed

Dincheva, Iva; Yang, Jianmin; Li, Anfei; Marinic, Tina; Freilingsdorf, Helena; Huang, Chienchun; Casey, B J; Hempstead, Barbara; Glatt, Charles E; Lee, Francis S; Bath, Kevin G; Jing, Deqiang

2017-12-01

Adolescence is a developmental stage in which the incidence of psychiatric disorders, such as anxiety disorders, peaks. Selective serotonin reuptake inhibitors (SSRIs) are the main class of agents used to treat anxiety disorders. However, the impact of SSRIs on the developing brain during adolescence remains unknown. The authors assessed the impact of developmentally timed SSRI administration in a genetic mouse model displaying elevated anxiety-like behaviors. Knock-in mice containing a common human single-nucleotide polymorphism (Val66Met; rs6265) in brain-derived neurotrophic factor (BDNF), a growth factor implicated in the mechanism of action of SSRIs, were studied based on their established phenotype of increased anxiety-like behavior. Timed administration of fluoxetine was delivered during one of three developmental periods (postnatal days 21-42, 40-61, or 60-81), spanning the transition from childhood to adulthood. Neurochemical and anxiety-like behavioral analyses were performed. We identified a "sensitive period" during periadolescence (postnatal days 21-42) in which developmentally timed fluoxetine administration rescued anxiety-like phenotypes in BDNF Val66Met mice in adulthood. Compared with littermate controls, BDNF Met/Met mice exhibited diminished maturation of serotonergic fibers projecting particularly to the prefrontal cortex, as well as decreased expression of the serotonergic trophic factor S100B in the dorsal raphe. Interestingly, deficient serotonergic innervation, as well as S100B levels, were rescued with fluoxetine administration during periadolescence. These findings suggest that SSRI administration during a "sensitive period" during periadolescence leads to long-lasting anxiolytic effects in a genetic mouse model of elevated anxiety-like behaviors. These persistent effects highlight the role of BDNF in the maturation of the serotonin system and the capacity to enhance its development through a pharmacological intervention.

Increasing proportions of tyrosine hydroxylase-immunoreactive interneurons colocalize with choline acetyltransferase or vasoactive intestinal peptide in the developing rat cerebral cortex

PubMed Central

Asmus, Stephen E.; Cocanougher, Benjamin T.; Allen, Donald L.; Boone, John B.; Brooks, Elizabeth A.; Hawkins, Sarah M.; Hench, Laura A.; Ijaz, Talha; Mayfield, Meredith N.

2011-01-01

Cortical interneurons are critical for information processing, and their dysfunction has been implicated in neurological disorders. One subset of this diverse cell population expresses tyrosine hydroxylase (TH) during postnatal rat development. Cortical TH-immunoreactive neurons appear at postnatal day (P) 16. The number of TH cells sharply increases between P16 and P20 and subsequently decreases to adult values. The absence of apoptotic markers in these cells suggests that the reduction in cell number is not due to cell death but is due to a decline in TH production. Cortical TH cells lack all additional catecholaminergic enzymes, and many coexpress GABA and calretinin, but little else is known about their phenotype or function. Because interneurons containing choline acetyltransferase (ChAT) or vasoactive intestinal peptide (VIP) share characteristics with cortical TH neurons, the coexpression of TH with ChAT or VIP was examined throughout the neocortex at P16, P20, and P30. The proportions of TH cell profiles double-labeled for ChAT or VIP significantly increased between P16 and P30. Based on their proximity to blood vessels, intrinsic cholinergic and VIPergic cells have been hypothesized to regulate cortical microcirculation. Labeling with the gliovascular marker aquaporin-4 revealed that at least half of the TH cells were apposed to microvessels at these ages, and many of these cells contained ChAT or VIP. Cortical TH neurons did not coproduce nitric oxide synthase. These results suggest that increasing proportions of cortical TH neurons express ChAT or VIP developmentally and that a subset of these TH neurons may regulate local blood flow. PMID:21295554

Ultrasonic vocalization impairment of Foxp2 (R552H) knockin mice related to speech-language disorder and abnormality of Purkinje cells

PubMed Central

Fujita, Eriko; Tanabe, Yuko; Shiota, Akira; Ueda, Masatsugu; Suwa, Kiyotaka; Momoi, Mariko Y.; Momoi, Takashi

2008-01-01

Previous studies have demonstrated that mutation in the forkhead domain of the forkhead box P2 (FOXP2) protein (R553H) causes speech-language disorders. To further analyze FOXP2 function in speech learning, we generated a knockin (KI) mouse for Foxp2 (R552H) [Foxp2 (R552H)-KI], corresponding to the human FOXP2 (R553H) mutation, by homologous recombination. Homozygous Foxp2 (R552H)-KI mice showed reduced weight, immature development of the cerebellum with incompletely folded folia, Purkinje cells with poor dendritic arbors and less synaptophysin immunoreactivity, and achieved crisis stage for survival 3 weeks after birth. At postnatal day 10, these mice also showed severe ultrasonic vocalization (USV) and motor impairment, whereas the heterozygous Foxp2 (R552H)-KI mice exhibited modest impairments. Similar to the wild-type protein, Foxp2 (R552H) localized in the nuclei of the Purkinje cells and the thalamus, striatum, cortex, and hippocampus (CA1) neurons of the homozygous Foxp2 (R552H)-KI mice (postnatal day 10), and some of the neurons showed nuclear aggregates of Foxp2 (R552H). In addition to the immature development of the cerebellum, Foxp2 (R552H) nuclear aggregates may further compromise the function of the Purkinje cells and cerebral neurons of the homozygous mice, resulting in their death. In contrast, heterozygous Foxp2 (R552H)-KI mice, which showed modest impairment of USVs with different USV qualities and which did not exhibit nuclear aggregates, should provide insights into the common molecular mechanisms between the mouse USV and human speech learning and the relationship between the USV and motor neural systems. PMID:18287060

[Electrophysiological characteristics of hippocampal postnatal early development mediated by AMPA receptors in rats].

PubMed

Chen, Xue-Yi; Zhang, Ai-Feng; Zhao, Wen; Gao, Yu-Dan; Duan, Hong-Mei; Hao, Peng; Yang, Zhao-Yang; Li, Xiao-Guang

2018-04-25

The present study was aimed to investigate the electrophysiological characteristics of hippocampal postnatal early development mediated by α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors in rats. Forty-eight Wistar rats were divided into postnatal 0.5-, 1-, 2- and 3-month groups (n = 12). Spontaneous excitatory postsynaptic currents (sEPSCs) and field excitatory postsynaptic potentials (fEPSPs) mediated by AMPA receptors were recorded to evaluate the changes in the intrinsic membrane properties of hippocampal CA1 pyramidal neurons by using patch-clamp and MED64 planar microelectrode array technique respectively. The results showed that, during the period of postnatal 0.5-3 months, some of the intrinsic membrane properties of hippocampal CA1 pyramidal neurons, such as the membrane capacitance (Cm) and the resting membrane potential (RMP), showed no significant changes, while the membrane input resistance (Rin) and the time constant (τ) of the cells were decreased significantly. The amplitude, frequency and kinetics (both rise and decay times) of sEPSCs were significantly increased during the period of postnatal 0.5-1 month, but they were all decreased during the period of postnatal 1-3 months. In addition, the range of evoked fEPSPs in hippocamal CA1 region was significantly expanded, but the fEPSP amplitudes were decreased significantly during the period of postnatal 0.5-3 months. Furthermore, the evoked fEPSPs could be significantly inhibited by extracellular application of the AMPA receptor antagonist 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX). These results suggest that AMPA receptor may act as a major type of excitatory receptor to regulate synaptic transmission and connections during the early stage of hippocampal postnatal development, which promotes the development and functional maturation of hippocampus in rats.

Maternal anxiety and infants' hippocampal development: timing matters.

PubMed

Qiu, A; Rifkin-Graboi, A; Chen, H; Chong, Y-S; Kwek, K; Gluckman, P D; Fortier, M V; Meaney, M J

2013-09-24

Exposure to maternal anxiety predicts offspring brain development. However, because children's brains are commonly assessed years after birth, the timing of such maternal influences in humans is unclear. This study aimed to examine the consequences of antenatal and postnatal exposure to maternal anxiety upon early infant development of the hippocampus, a key structure for stress regulation. A total of 175 neonates underwent magnetic resonance imaging (MRI) at birth and among them 35 had repeated scans at 6 months of age. Maternal anxiety was assessed using the State-Trait Anxiety Inventory (STAI) at week 26 of pregnancy and 3 months after delivery. Regression analyses showed that antenatal maternal anxiety did not influence bilateral hippocampal volume at birth. However, children of mothers reporting increased anxiety during pregnancy showed slower growth of both the left and right hippocampus over the first 6 months of life. This effect of antenatal maternal anxiety upon right hippocampal growth became statistically stronger when controlling for postnatal maternal anxiety. Furthermore, a strong positive association between postnatal maternal anxiety and right hippocampal growth was detected, whereas a strong negative association between postnatal maternal anxiety and the left hippocampal volume at 6 months of life was found. Hence, the postnatal growth of bilateral hippocampi shows distinct responses to postnatal maternal anxiety. The size of the left hippocampus during early development is likely to reflect the influence of the exposure to perinatal maternal anxiety, whereas right hippocampal growth is constrained by antenatal maternal anxiety, but enhanced in response to increased postnatal maternal anxiety.

Timing and Duration of Drug Exposure Affects Outcomes of a Drug-Nutrient Interaction During Ontogeny.

PubMed

Ling, Binbing; Aziz, Caroline; Wojnarowicz, Chris; Olkowski, Andrew; Alcorn, Jane

2010-10-14

Significant drug-nutrient interactions are possible when drugs and nutrients share the same absorption and disposition mechanisms. During postnatal development, the outcomes of drug-nutrient interactions may change with postnatal age since these processes undergo ontogenesis through the postnatal period. Our study investigated the dependence of a significant drug-nutrient interaction (cefepime-carnitine) on the timing and duration of drug exposure relative to postnatal age. Rat pups were administered cefepime (5 mg/kg) twice daily subcutaneously according to different dosing schedules (postnatal day 1-4, 1-8, 8-11, 8-20, or 1-20). Cefepime significantly reduced serum and heart L-carnitine levels in postnatal day 1-4, 1-8 and 8-11 groups and caused severe degenerative changes in ventricular myocardium in these groups. Cefepime also altered the ontogeny of several key L-carnitine homeostasis pathways. The qualitative and quantitative changes in levels of hepatic γ-butyrobetaine hydroxylase mRNA and activity, hepatic trimethyllysine hydroxlase mRNA, intestinal organic cation/carnitine transporter (Octn) mRNA, and renal Octn2 mRNA depended on when during postnatal development the cefepime exposure occurred and duration of exposure. Despite lower levels of heart L-carnitine in earlier postnatal groups, levels of carnitine palmitoyltransferase mRNA and activity, heart Octn2 mRNA and ATP levels in all treatment groups remained unchanged with cefepime exposure. However, changes in other high energy phosphate substrates were noted and reductions in the phosphocreatine/ATP ratio were found in rat pups with normal serum L-carnitine levels. In summary, our data suggest a significant drug-nutrient transport interaction in developing neonates, the nature of which depends on the timing and duration of exposure relative to postnatal age.

Timing and Duration of Drug Exposure Affects Outcomes of a Drug-Nutrient Interaction During Ontogeny

PubMed Central

Ling, Binbing; Aziz, Caroline; Wojnarowicz, Chris; Olkowski, Andrew; Alcorn, Jane

2010-01-01

Significant drug-nutrient interactions are possible when drugs and nutrients share the same absorption and disposition mechanisms. During postnatal development, the outcomes of drug-nutrient interactions may change with postnatal age since these processes undergo ontogenesis through the postnatal period. Our study investigated the dependence of a significant drug-nutrient interaction (cefepime-carnitine) on the timing and duration of drug exposure relative to postnatal age. Rat pups were administered cefepime (5 mg/kg) twice daily subcutaneously according to different dosing schedules (postnatal day 1-4, 1-8, 8-11, 8-20, or 1-20). Cefepime significantly reduced serum and heart L-carnitine levels in postnatal day 1-4, 1-8 and 8-11 groups and caused severe degenerative changes in ventricular myocardium in these groups. Cefepime also altered the ontogeny of several key L-carnitine homeostasis pathways. The qualitative and quantitative changes in levels of hepatic γ-butyrobetaine hydroxylase mRNA and activity, hepatic trimethyllysine hydroxlase mRNA, intestinal organic cation/carnitine transporter (Octn) mRNA, and renal Octn2 mRNA depended on when during postnatal development the cefepime exposure occurred and duration of exposure. Despite lower levels of heart L-carnitine in earlier postnatal groups, levels of carnitine palmitoyltransferase mRNA and activity, heart Octn2 mRNA and ATP levels in all treatment groups remained unchanged with cefepime exposure. However, changes in other high energy phosphate substrates were noted and reductions in the phosphocreatine/ATP ratio were found in rat pups with normal serum L-carnitine levels. In summary, our data suggest a significant drug-nutrient transport interaction in developing neonates, the nature of which depends on the timing and duration of exposure relative to postnatal age. PMID:27721360

SUBSTANCE-ABUSING MOTHERS IN RESIDENTIAL TREATMENT WITH THEIR BABIES: IMPORTANCE OF PRE- AND POSTNATAL MATERNAL REFLECTIVE FUNCTIONING

PubMed Central

Pajulo, Marjukka; Pyykkönen, Nina; Kalland, Mirjam; Sinkkonen, Jari; Helenius, Hans; Punamäki, Raija-Leena; Suchman, Nancy

2012-01-01

A residential treatment program has been developed specifically for substance-abusing pregnant and parenting women in Finland, focusing on simultaneously supporting maternal abstinence from substances and the mother–baby relationship. The aims of the study are to explore maternal pre- and postnatal reflective functioning and its association with background factors, maternal exposure to trauma, and psychiatric symptoms, postnatal interaction, child development, and later child foster care placement. Participants were 34 mother–baby pairs living in three residential program units during the pre- to postnatal period. We employed self-report questionnaires on background, trauma history, and psychiatric symptoms (Brief Symptom Inventory: L.R. Derogatis, 1993; Edinburgh Postnatal Depression Scale: J.L. Cox, J.M. Holden, & R. Sagovsky, 1987; Traumatic Antecedents Questionnaire: B. Van der Kolk, 2003), videotaped mother–child interactions coded for sensitivity, control, and unresponsiveness (Care Index for Infants and Toddlers: P. Crittenden, 2003); a standardized test of child development (Bayley Scales of Infant Development-II: N. Bayley, 1993); and semistructured interviews for maternal reflective functioning (Pregnancy Interview: A. Slade, E. Bernbach, J. Grienenberger, D.W. Levy, & A. Locker, 2002; Parent Development Interview: A. Slade et al., 2005). Pre- and postnatal maternal reflective functioning (RF) was on average low, but varied considerably across participants. Average RF increased significantly during the intervention. Increase in RF level was found to be associated with type of abused substance and maternal trauma history. Mothers who showed lower postnatal RF levels relapsed to substance use more often after completing a residential treatment period, and their children were more likely to be placed in foster care. The intensive focus on maternal RF is an important direction in the development of efficacious treatment for this very high risk population. PMID:22899872

Absolute quantitation of phosphorus metabolites in the cerebral cortex of the newborn human infant and in the forearm muscles of young adults using a double-tuned surface coil

NASA Astrophysics Data System (ADS)

Cady, Ernest B.

The application of a double-tuned surface coil with strong coupling for both 31P and 1H to the in vivo measurement of metabolite concentrations by NMR spectroscopy is demonstrated. It is shown that sample loading, although important for a coil tuned to a single frequency, does not necessarily have a significant effect on absolute quantitation results if the coil is strongly coupled to the sample for both nuclei. For the coil used in the present study, the spectrometer calibration coefficient is almost independent of loading and the 1H and 31P flip angles at the coil center produced by fixed length pulses could be arranged to be nearly equal over a range of loading conditions. In seven normal infants, of gestational plus postnatal age 35 to 37 weeks, the cerebral cortex nucleotide triphosphate concentration was 3.7 ± 0.6 m M/liter wet (mean ± SD). Metabolite concentrations were low in the cerebral cortex of a severely birth asphyxiated infant. The adenosine triphosphate concentration in the resting, fresh forearm muscles of six young adults was 6.3 ± 0.8 m M/liter wet.

Carboxyhemoglobin Formation in Preterm Infants Is Related to the Subsequent Development of Bronchopulmonary Dysplasia

PubMed Central

Tokuriki, Shuko; Okuno, Takashi; Ohta, Genrei

2015-01-01

Objective. To evaluate the usefulness of carboxyhemoglobin (CO-Hb) levels as a biomarker to predict the development and severity of bronchopulmonary dysplasia (BPD). Methods. Twenty-five infants born at <33 wk of gestational age or with a birth weight of <1,500 g were enrolled. CO-Hb levels were measured between postnatal days 5 and 8, 12 and 15, 19 and 22, and 26 and 29. Urinary levels of 8-hydroxydeoxyguanosine (8-OHdG), advanced oxidation protein products, and Nε-(hexanoyl) lysine were measured between postnatal days 5 and 8 and 26 and 29. Receiver operating characteristic (ROC) analysis was used to compare the biomarkers' predictive values. Results. Compared with infants in the no-or-mild BPD group, infants with moderate-to-severe BPD exhibited higher CO-Hb levels during the early postnatal period and higher 8-OHdG levels between postnatal days 5 and 8. Using ROC analysis to predict the development of moderate-to-severe BPD, the area under the curve (AUC) for CO-Hb levels between postnatal days 5 and 8 was higher than AUCs for the urinary markers. Conclusions. CO-Hb levels during the early postnatal period may serve as a practical marker for evaluating oxidative stress and the severity of subsequently developing BPD. PMID:26294808

Carboxyhemoglobin Formation in Preterm Infants Is Related to the Subsequent Development of Bronchopulmonary Dysplasia.

PubMed

Tokuriki, Shuko; Okuno, Takashi; Ohta, Genrei; Ohshima, Yusei

2015-01-01

To evaluate the usefulness of carboxyhemoglobin (CO-Hb) levels as a biomarker to predict the development and severity of bronchopulmonary dysplasia (BPD). Twenty-five infants born at <33 wk of gestational age or with a birth weight of <1,500 g were enrolled. CO-Hb levels were measured between postnatal days 5 and 8, 12 and 15, 19 and 22, and 26 and 29. Urinary levels of 8-hydroxydeoxyguanosine (8-OHdG), advanced oxidation protein products, and Nε-(hexanoyl) lysine were measured between postnatal days 5 and 8 and 26 and 29. Receiver operating characteristic (ROC) analysis was used to compare the biomarkers' predictive values. Compared with infants in the no-or-mild BPD group, infants with moderate-to-severe BPD exhibited higher CO-Hb levels during the early postnatal period and higher 8-OHdG levels between postnatal days 5 and 8. Using ROC analysis to predict the development of moderate-to-severe BPD, the area under the curve (AUC) for CO-Hb levels between postnatal days 5 and 8 was higher than AUCs for the urinary markers. CO-Hb levels during the early postnatal period may serve as a practical marker for evaluating oxidative stress and the severity of subsequently developing BPD.

Hydroxyurea Treatment and Development of the Rat Cerebellum: Effects on the Neurogenetic Profiles and Settled Patterns of Purkinje Cells and Deep Cerebellar Nuclei Neurons.

PubMed

Martí, Joaquín; Santa-Cruz, M C; Serra, Roger; Hervás, José P

2016-11-01

The current paper analyzes the development of the male and female rat cerebellum exposed to hydroxyurea (HU) (300 or 600 mg/kg) as embryo and collected at postnatal day 90. Our study reveals that the administration of this drug compromises neither the cytoarchitecture of the cerebellar cortex nor deep nuclei (DCN). However, in comparison with the saline group, we observed that several cerebellar parameters were lower in the HU injected groups. These parameters included area of the cerebellum, cerebellar cortex length, molecular layer area, Purkinje cell number, granule cell counts, internal granular layer, white matter and cerebellar nuclei areas, and number of deep cerebellar nuclei neurons. These features were larger in the rats injected with saline, smaller in those exposed to 300 mg/kg of HU and smallest in the group receiving 600 mg/kg of this agent. No sex differences in the effect of the HU were observed. In addition, we infer the neurogenetic timetables and the neurogenetic gradients of PCs and DCN neurons in rats exposed to either saline or HU as embryos. For this purpose, 5-bromo-2'-deoxyuridine was injected into pregnant rats previously administered with saline or HU. This thymidine analog was administered following a progressively delayed cumulative labeling method. The data presented here show that systematic differences exist in the pattern of neurogenesis and in the spatial location of cerebellar neurons between rats injected with saline or HU. No sex differences in the effect of the HU were observed. These findings have implications for the administration of this compound to women in gestation as the effects of HU on the development of the cerebellum might persist throughout their offsprings' life.

Rethinking schizophrenia in the context of normal neurodevelopment

PubMed Central

Catts, Vibeke S.; Fung, Samantha J.; Long, Leonora E.; Joshi, Dipesh; Vercammen, Ans; Allen, Katherine M.; Fillman, Stu G.; Rothmond, Debora A.; Sinclair, Duncan; Tiwari, Yash; Tsai, Shan-Yuan; Weickert, Thomas W.; Shannon Weickert, Cynthia

2013-01-01

The schizophrenia brain is differentiated from the normal brain by subtle changes, with significant overlap in measures between normal and disease states. For the past 25 years, schizophrenia has increasingly been considered a neurodevelopmental disorder. This frame of reference challenges biological researchers to consider how pathological changes identified in adult brain tissue can be accounted for by aberrant developmental processes occurring during fetal, childhood, or adolescent periods. To place schizophrenia neuropathology in a neurodevelopmental context requires solid, scrutinized evidence of changes occurring during normal development of the human brain, particularly in the cortex; however, too often data on normative developmental change are selectively referenced. This paper focuses on the development of the prefrontal cortex and charts major molecular, cellular, and behavioral events on a similar time line. We first consider the time at which human cognitive abilities such as selective attention, working memory, and inhibitory control mature, emphasizing that attainment of full adult potential is a process requiring decades. We review the timing of neurogenesis, neuronal migration, white matter changes (myelination), and synapse development. We consider how molecular changes in neurotransmitter signaling pathways are altered throughout life and how they may be concomitant with cellular and cognitive changes. We end with a consideration of how the response to drugs of abuse changes with age. We conclude that the concepts around the timing of cortical neuronal migration, interneuron maturation, and synaptic regression in humans may need revision and include greater emphasis on the protracted and dynamic changes occurring in adolescence. Updating our current understanding of post-natal neurodevelopment should aid researchers in interpreting gray matter changes and derailed neurodevelopmental processes that could underlie emergence of psychosis. PMID:23720610

Effects of experimental suppression of active (REM) sleep during early development upon adult brain and behavior in the rat.

PubMed

Mirmiran, M; Scholtens, J; van de Poll, N E; Uylings, H B; van der Gugten, J; Boer, G J

1983-04-01

In order to test the hypothesis that active sleep (AS) is important for the normal development of the central nervous system, 3 different deprivation methods were applied to male Wistar rat pups during the first month of life. Daily injection of clomipramine from 8 to 21 days of age reduced the high level of AS to less than the adult value throughout most of the experimental period. Administration of clonidine from 8 to 21 days of life induced an almost total suppression of AS. Instrumental deprivation, using the 'pendulum' method, led to a significant (but less severe) AS reduction during 2-4 weeks of postnatal age. Open-field behavior testing in adulthood revealed a higher than normal level of ambulation in all 3 experimental groups. Masculine sexual responses were deficient, due to a low level of both mounts and ejaculations, in both clomipramine- and clonidine-treated animals. Neither passive avoidance learning nor dark preference tests revealed any differences between the experimental and control rats. Sleep observations showed that there was an abnormally high incidence of large myoclonic jerks during AS in both clomipramine- and clonidine-treated rats. Subsequent measurement of regional brain weights showed a significant reduction in the cerebral cortex and medulla oblongata, as compared with the respective control groups, in both the clomipramine- and the clonidine-treated rats. In addition, DNA and protein determination in the affected brain areas showed a proportional reduction in the cortex and in the medulla. These results demonstrate that interference with normal functioning either of AS per se or of specific monoaminergic transmitter systems during early development can produce long-lasting behavioral as well as brain morphological and biochemical abnormalities in later life.

Early-life stress impacts the developing hippocampus and primes seizure occurrence: cellular, molecular, and epigenetic mechanisms

PubMed Central

Huang, Li-Tung

2014-01-01

Early-life stress includes prenatal, postnatal, and adolescence stress. Early-life stress can affect the development of the hypothalamic-pituitary-adrenal (HPA) axis, and cause cellular and molecular changes in the developing hippocampus that can result in neurobehavioral changes later in life. Epidemiological data implicate stress as a cause of seizures in both children and adults. Emerging evidence indicates that both prenatal and postnatal stress can prime the developing brain for seizures and an increase in epileptogenesis. This article reviews the cellular and molecular changes encountered during prenatal and postnatal stress, and assesses the possible link between these changes and increases in seizure occurrence and epileptogenesis in the developing hippocampus. In addititon, the priming effect of prenatal and postnatal stress for seizures and epileptogenesis is discussed. Finally, the roles of epigenetic modifications in hippocampus and HPA axis programming, early-life stress, and epilepsy are discussed. PMID:24574961

Association between Prenatal and Postnatal Psychological Distress and Toddler Cognitive Development: A Systematic Review

PubMed Central

2015-01-01

Purpose Maternal psychological distress is one of the most common perinatal complications, affecting up to 25% of pregnant and postpartum women. Research exploring the association between prenatal and postnatal distress and toddler cognitive development has not been systematically compiled. The objective of this systematic review was to determine the association between prenatal and postnatal psychological distress and toddler cognitive development. Methods Articles were included if: a) they were observational studies published in English; b) the exposure was prenatal or postnatal psychological distress; c) cognitive development was assessed from 13 to 36 months; d) the sample was recruited in developed countries; and e) exposed and unexposed women were included. A university-based librarian conducted a search of electronic databases (Embase, CINAHL, Eric, PsycInfo, Medline) (January, 1990-March, 2014). We searched gray literature, reference lists, and relevant journals. Two reviewers independently evaluated titles/abstracts for inclusion, and quality using the Scottish Intercollegiate Guideline Network appraisal tool for observational studies. One reviewer extracted data using a standardized form. Results Thirteen of 2448 studies were included. There is evidence of an association between prenatal and postnatal distress and cognitive development. While variable effect sizes were reported for postnatal associations, most studies reported medium effect sizes for the association between prenatal psychological distress and cognitive development. Too few studies were available to determine the influence of the timing of prenatal exposure on cognitive outcomes. Conclusion Findings support the need for early identification and treatment of perinatal mental health problems as a potential strategy for optimizing toddler cognitive development. PMID:25996151

Association between Prenatal and Postnatal Psychological Distress and Toddler Cognitive Development: A Systematic Review.

PubMed

Kingston, Dawn; McDonald, Sheila; Austin, Marie-Paule; Tough, Suzanne

2015-01-01

Maternal psychological distress is one of the most common perinatal complications, affecting up to 25% of pregnant and postpartum women. Research exploring the association between prenatal and postnatal distress and toddler cognitive development has not been systematically compiled. The objective of this systematic review was to determine the association between prenatal and postnatal psychological distress and toddler cognitive development. Articles were included if: a) they were observational studies published in English; b) the exposure was prenatal or postnatal psychological distress; c) cognitive development was assessed from 13 to 36 months; d) the sample was recruited in developed countries; and e) exposed and unexposed women were included. A university-based librarian conducted a search of electronic databases (Embase, CINAHL, Eric, PsycInfo, Medline) (January, 1990-March, 2014). We searched gray literature, reference lists, and relevant journals. Two reviewers independently evaluated titles/abstracts for inclusion, and quality using the Scottish Intercollegiate Guideline Network appraisal tool for observational studies. One reviewer extracted data using a standardized form. Thirteen of 2448 studies were included. There is evidence of an association between prenatal and postnatal distress and cognitive development. While variable effect sizes were reported for postnatal associations, most studies reported medium effect sizes for the association between prenatal psychological distress and cognitive development. Too few studies were available to determine the influence of the timing of prenatal exposure on cognitive outcomes. Findings support the need for early identification and treatment of perinatal mental health problems as a potential strategy for optimizing toddler cognitive development.

Migrating Interneurons Secrete Fractalkine to Promote Oligodendrocyte Formation in the Developing Mammalian Brain.

PubMed

Voronova, Anastassia; Yuzwa, Scott A; Wang, Beatrix S; Zahr, Siraj; Syal, Charvi; Wang, Jing; Kaplan, David R; Miller, Freda D

2017-05-03

During development, newborn interneurons migrate throughout the embryonic brain. Here, we provide evidence that these interneurons act in a paracrine fashion to regulate developmental oligodendrocyte formation. Specifically, we show that medial ganglionic eminence (MGE) interneurons secrete factors that promote genesis of oligodendrocytes from glially biased cortical precursors in culture. Moreover, when MGE interneurons are genetically ablated in vivo prior to their migration, this causes a deficit in cortical oligodendrogenesis. Modeling of the interneuron-precursor paracrine interaction using transcriptome data identifies the cytokine fractalkine as responsible for the pro-oligodendrocyte effect in culture. This paracrine interaction is important in vivo, since knockdown of the fractalkine receptor CX3CR1 in embryonic cortical precursors, or constitutive knockout of CX3CR1, causes decreased numbers of oligodendrocyte progenitor cells (OPCs) and oligodendrocytes in the postnatal cortex. Thus, in addition to their role in regulating neuronal excitability, interneurons act in a paracrine fashion to promote the developmental genesis of oligodendrocytes. Copyright © 2017 Elsevier Inc. All rights reserved.

Coordinated Gene Expression of Neuroinflammatory and Cell Signaling Markers in Dorsolateral Prefrontal Cortex during Human Brain Development and Aging

PubMed Central

Primiani, Christopher T.; Ryan, Veronica H.; Rao, Jagadeesh S.; Cam, Margaret C.; Ahn, Kwangmi; Modi, Hiren R.; Rapoport, Stanley I.

2014-01-01

Background Age changes in expression of inflammatory, synaptic, and neurotrophic genes are not well characterized during human brain development and senescence. Knowing these changes may elucidate structural, metabolic, and functional brain processes over the lifespan, as well vulnerability to neurodevelopmental or neurodegenerative diseases. Hypothesis Expression levels of inflammatory, synaptic, and neurotrophic genes in the human brain are coordinated over the lifespan and underlie changes in phenotypic networks or cascades. Methods We used a large-scale microarray dataset from human prefrontal cortex, BrainCloud, to quantify age changes over the lifespan, divided into Development (0 to 21 years, 87 brains) and Aging (22 to 78 years, 144 brains) intervals, in transcription levels of 39 genes. Results Gene expression levels followed different trajectories over the lifespan. Many changes were intercorrelated within three similar groups or clusters of genes during both Development and Aging, despite different roles of the gene products in the two intervals. During Development, changes were related to reported neuronal loss, dendritic growth and pruning, and microglial events; TLR4, IL1R1, NFKB1, MOBP, PLA2G4A, and PTGS2 expression increased in the first years of life, while expression of synaptic genes GAP43 and DBN1 decreased, before reaching plateaus. During Aging, expression was upregulated for potentially pro-inflammatory genes such as NFKB1, TRAF6, TLR4, IL1R1, TSPO, and GFAP, but downregulated for neurotrophic and synaptic integrity genes such as BDNF, NGF, PDGFA, SYN, and DBN1. Conclusions Coordinated changes in gene transcription cascades underlie changes in synaptic, neurotrophic, and inflammatory phenotypic networks during brain Development and Aging. Early postnatal expression changes relate to neuronal, glial, and myelin growth and synaptic pruning events, while late Aging is associated with pro-inflammatory and synaptic loss changes. Thus, comparable transcriptional regulatory networks that operate throughout the lifespan underlie different phenotypic processes during Aging compared to Development. PMID:25329999

Coordinated gene expression of neuroinflammatory and cell signaling markers in dorsolateral prefrontal cortex during human brain development and aging.

PubMed

Primiani, Christopher T; Ryan, Veronica H; Rao, Jagadeesh S; Cam, Margaret C; Ahn, Kwangmi; Modi, Hiren R; Rapoport, Stanley I

2014-01-01

Age changes in expression of inflammatory, synaptic, and neurotrophic genes are not well characterized during human brain development and senescence. Knowing these changes may elucidate structural, metabolic, and functional brain processes over the lifespan, as well vulnerability to neurodevelopmental or neurodegenerative diseases. Expression levels of inflammatory, synaptic, and neurotrophic genes in the human brain are coordinated over the lifespan and underlie changes in phenotypic networks or cascades. We used a large-scale microarray dataset from human prefrontal cortex, BrainCloud, to quantify age changes over the lifespan, divided into Development (0 to 21 years, 87 brains) and Aging (22 to 78 years, 144 brains) intervals, in transcription levels of 39 genes. Gene expression levels followed different trajectories over the lifespan. Many changes were intercorrelated within three similar groups or clusters of genes during both Development and Aging, despite different roles of the gene products in the two intervals. During Development, changes were related to reported neuronal loss, dendritic growth and pruning, and microglial events; TLR4, IL1R1, NFKB1, MOBP, PLA2G4A, and PTGS2 expression increased in the first years of life, while expression of synaptic genes GAP43 and DBN1 decreased, before reaching plateaus. During Aging, expression was upregulated for potentially pro-inflammatory genes such as NFKB1, TRAF6, TLR4, IL1R1, TSPO, and GFAP, but downregulated for neurotrophic and synaptic integrity genes such as BDNF, NGF, PDGFA, SYN, and DBN1. Coordinated changes in gene transcription cascades underlie changes in synaptic, neurotrophic, and inflammatory phenotypic networks during brain Development and Aging. Early postnatal expression changes relate to neuronal, glial, and myelin growth and synaptic pruning events, while late Aging is associated with pro-inflammatory and synaptic loss changes. Thus, comparable transcriptional regulatory networks that operate throughout the lifespan underlie different phenotypic processes during Aging compared to Development.

Behavioral and cellular consequences of increasing serotonergic activity during brain development: a role in autism?

PubMed

Whitaker-Azmitia, Patricia M

2005-02-01

The hypothesis explored in this review is that the high levels of serotonin in the blood seen in some autistic children (the so-called hyperserotonemia of autism) may lead to some of the behavioral and cellular changes also observed in the disorder. At early stages of development, when the blood-brain Barrier is not yet fully formed, the high levels of serotonin in the blood can enter the brain of a developing fetus and cause loss of serotonin terminals through a known negative feedback function of serotonin during development. The loss of serotonin innervation persists throughout subsequent development and the symptoms of autism appear. A review of the basic scientific literature on prenatal treatments affecting serotonin is given, in support of this hypothesis, with an emphasis on studies using the serotonin agonist, 5-methoxytryptamine (5-MT). In work using 5-MT to mimic hyperserotonemia, Sprague-Dawley rats are treated from gestational day 12 until postnatal 20. In published reports, these animals have been found to have a significant loss of serotonin terminals, decreased metabolic activity in cortex, changes in columnar development in cortex, changes in serotonin receptors, and "autistic-like" behaviors. In preliminary cellular findings given in this review, the animals have also been found to have cellular changes in two relevant brain regions: 1. Central nucleus of the amygdala, a brain region involved in fear-responding, where an increase in calcitonin gene related peptide (CGRP) was found 2. Paraventricular nucleus of the hypothalamus, a brain region involved in social memory and bonding, where a decrease in oxytocin was found. Both of these cellular changes could result from loss of serotonin innervation, possibly due to loss of terminal outgrowth from the same cells of the raphe nuclei. Thus, increased serotonergic activity during development could damage neurocircuitry involved in emotional responding to social stressors and may have relevance to the symptoms of autism.

[Prospective study on the impact of infantile cytomegalovirus infection on growth and development of infants].

PubMed

2010-05-01

To understand the situation of postnatal cytomegalovirus (CMV) infection in Beijing and its impact on infant. From November 2004 to March 2008, a multicenter cohort study on maternal, neonatal and infantile CMV infection was carried out in four hospitals in Beijing. Two hundred and ten infants without congenital infections were enrolled into this study. Their serum IgG antibody to CMV was determined at the age of 1 year. According to the results of CMV DNA at 12 weeks of age and the CMV IgG results at 1 year of age, they were divided into three groups, perinatal infection group, postnatal infection group and postnatal non-infection group. The information of their mothers, the data of their growth and development at 1 year of age, development quotient, their eyes and their auditory function were analyzed. The risk factors of the postnatal cytomegalovirus infection were analyzed by multi-factorial logistic regression. Of the 210 infants, 42 had perinatal infection, 98 had postnatal infection and 70 had no infection. The postnatal cytomegalovirus infection rate was 46.40%, taken into account the congenital infection rate and perinatal infection rate, the total cytomegalovirus infection rate was 66.85% at 1 year of age. The clinical manifestation, developmental status and the quotient of development from three groups at birth and at 1 year of age were analyzed. No significant difference was found. In postnatal cytomegalovirus infection group the rates of breast feeding, mixed feeding and formula feeding were 87.76%, 9.18% and 3.06%, respectively; while in no infection group the rates were 61.43%, 21.43% and 17.14%, respectively(chi(2) = 17.040, P < 0.01). CMV infection is present widely in China. Non-breast feeding is an important protective factor. Postnatal cytomegalovirus infection in infants had no significant impact on the health and development of infants.

From antenatal to postnatal depression: associated factors and mitigating influences.

PubMed

Redshaw, Maggie; Henderson, Jane

2013-06-01

Postnatal depression has a serious impact on new mothers and their children and families. Risk factors identified include a history of depression, multiparity, and young age. The study aimed to investigate factors associated with experiencing antenatal depression and developing subsequent postnatal depression. The study utilized survey data from 5332 women about their experience and well-being during pregnancy, in labor, and postnatally up to 3 months. Prespecified sociodemographic and clinical variables were tabulated against the incidence of antenatal depression and postnatal depression. Binary logistic regression was used to estimate the effects of the principal underlying variables. Risk factors for antenatal depression were multiparity, black and minority ethnic (BME) status, physical or mental health problems, living in a deprived area, and unplanned pregnancy. Different factors for postnatal depression were evident among women who had experienced antenatal depression: multiparity and BME status were protective, whereas being left alone in labor and experiencing poor postnatal health increased the risk of postnatal depression. This study confirms previous research on risk factors for antenatal depression and stresses the importance of continuous support in labor and vigilance in the postnatal period regarding the potential ill effects of continuing postnatal health problems.

Anger in the context of postnatal depression: An integrative review.

PubMed

Ou, Christine H; Hall, Wendy A

2018-05-20

Contrary to social constructions of new motherhood as a joyous time, mothers may experience postnatal depression and anger. Although postnatal depression has been thoroughly studied, the expression of maternal anger in the context of postnatal depression is conceptually unclear. This integrative review investigated the framing of anger in the context of postnatal depression. After undertaking a search of CINAHL, Ovid-Medline, PsycInfo, and Web of Science, we identified qualitative (n = 7) and quantitative (n = 17) papers that addressed maternal anger and postnatal depression. We analyzed the data by developing themes. Our review indicated that anger was a salient mood disturbance for some postnatally depressed women with themes integrated as: (i) anger accompanying depression, (ii) powerlessness as a component of depression and anger, and (iii) anger occurring as a result of expectations being violated. Our findings indicate that anger can coexist with women's postnatal depression. Anger can be expressed toward the self and toward children and family members with negative relationship effects. We recommend that health care providers and researchers consider anger in the context of postnatal mood disturbances. © 2018 Wiley Periodicals, Inc.

Predictors of postnatal mother-infant bonding: the role of antenatal bonding, maternal substance use and mental health.

PubMed

Rossen, Larissa; Hutchinson, Delyse; Wilson, Judy; Burns, Lucy; A Olsson, Craig; Allsop, Steve; J Elliott, Elizabeth; Jacobs, Sue; Macdonald, Jacqueline A; Mattick, Richard P

2016-08-01

The emotional bond that a mother feels towards her baby is critical to social, emotional and cognitive development. Maternal health and wellbeing through pregnancy and antenatal bonding also play a key role in determining bonding postnatally, but the extent to which these relationships may be disrupted by poor mental health or substance use is unclear. This study aimed to examine the extent to which mother-fetal bonding, substance use and mental health through pregnancy predicted postnatal mother-infant bonding at 8 weeks. Participants were 372 women recruited from three metropolitan hospitals in Australia. Data was collected during trimesters one, two and three of pregnancy and 8 weeks postnatal using the Maternal Antenatal Attachment Scale (MAAS), Maternal Postnatal Attachment Scale (MPAS), the Edinburgh Antenatal and Postnatal Depression Scale (EPDS), the Depression and Anxiety Scales (DASS-21), frequency and quantity of substance use (caffeine, alcohol and tobacco) as well as a range of demographic and postnatal information. Higher antenatal bonding predicted higher postnatal bonding at all pregnancy time-points in a fully adjusted regression model. Maternal depressive symptoms in trimesters two and three and stress in trimester two were inversely related to poorer mother-infant bonding 8 weeks postnatally. This study extends previous work on the mother's felt bond to her developing child by drawing on a large sample of women and documenting the pattern of this bond at three time points in pregnancy and at 8 weeks postnatally. Utilising multiple antenatal waves allowed precision in isolating the relationships in pregnancy and at key intervention points. Investigating methods to enhance bonding and intervene in pregnancy is needed. It is also important to assess maternal mental health through pregnancy.

Activation of GABA-A receptors during postnatal brain development increases anxiety- and depression-related behaviors in a time- and dose-dependent manner in adult mice.

PubMed

Salari, Ali-Akbar; Bakhtiari, Amir; Homberg, Judith R

2015-08-01

Disturbances of the gamma-amino butyric acid-ergic (GABAergic) system during postnatal development can have long-lasting consequences for later life behavior, like the individual's response to stress. However, it is unclear which postnatal windows of sensitivity to GABA-ergic modulations are associated with what later-life behavioral outcomes. Therefore, we sought to determine whether neonatal activation of the GABA-A receptor during two postnatal periods, an early window (postnatal day 3-5) and a late window (postnatal day 14-16), can affect anxiety- and depression-related behaviors in male mice in later life. To this end, mice were treated with either saline or muscimol (50, 100, 200, 300 and 500μg/kg) during the early and late postnatal periods. An additional group of mice was treated with the GABA-A receptor antagonist bicuculline+muscimol. When grown to adulthood male mice were exposed to behavioral tests to measure anxiety- and depression-related behaviors. Baseline and stress-induced corticosterone (CORT) levels were also measured. The results indicate that early postnatal and to a lesser extent later postnatal exposure to the GABA-A receptor agonist muscimol increased anxiety-like behavior and stress-induced CORT levels in adults. Moreover, the early postnatal treatment with muscimol increased depression-like behavior with increasing baseline CORT levels. The anxiogenic and depression-like later-life consequences could be antagonized by bicuculline. Our findings suggest that GABA-A receptor signaling during early-life can influence anxiety- and depression-related behaviors in a time- and dose-dependent manner in later life. Our findings help to increase insight in the developmental mechanisms contributing to stress-related disorders. Copyright © 2015 Elsevier B.V. and ECNP. All rights reserved.

Androgen imprinting of the brain in animal models and humans with intersex disorders: review and recommendations.

PubMed

Hrabovszky, Zoltan; Hutson, John M

2002-11-01

Psychosexual development, gender assignment and surgical treatment in patients with intersex are controversial issues in the medical literature. Some groups are of the opinion that gender identity and sexual orientation are determined prenatally secondary to the fetal hormonal environment causing irreversible development of the nervous system. We reviewed the evidence in animal and human studies to determine the possible role of early postnatal androgen production in gender development. An extensive literature review was performed of data from animal experiments and human studies. RESULTS Many animal studies show that adding or removing hormonal stimulus in early postnatal life can profoundly alter gender behavior of the adult animal. Human case studies show that late intervention is unable to reverse gender orientation from male to female. Most studies have not permitted testing of whether early gender assignment and treatment as female with suppression/ablation of postnatal androgen production leads to improved concordance of the gender identity and sex of rearing. Animal studies support a role for postnatal androgens in brain/behavior development with human studies neither completely supportive nor antagonistic. Therefore, gender assignment in infants with intersex should be made with the possibility in mind that postnatal testicular hormones at ages 1 to 6 months may affect gender identity. A case-control study is required to test the hypothesis that postnatal androgen exposure may convert ambisexual brain functions to committed male behavior patterns.

Expression analysis of an evolutionarily conserved metallophosphodiesterase gene, Mpped1, in the normal and beta-catenin-deficient malformed dorsal telencephalon.

PubMed

Chen, Chun-Ming; Wang, Hsuan-Yao; You, Li-Ru; Shang, Rong-Li; Liu, Fu-Chin

2010-06-01

We report the expression of the mouse Mpped1 in the telencephalon through embryonic stages to adulthood. Using Northern blotting analysis and RNA in situ hybridization (ISH), our data show that Mpped1 is specifically expressed in the brain and is enriched in the cortical plate of the developing telencephalon. Postnatally, the expression of Mpped1 is reduced in the cerebral cortex relative to its levels in the embryonic dorsal telencephalon. Also, Mpped1 expression is sustained in the hippocampal CA1 region. Examination of the expression of Mpped1 and other cortical layer markers by ISH in a malformed beta-catenin null dorsal telencephalon show that the Mpped1-, Cux2-, and Rorbeta-expressing superficial cortical layers are reduced and form patchy patterns, and the Tbr-1-expressing deep-layer neurons are incorrectly located on superficial layers, indicative of a migration defect of cortical neurons in the absence of beta-catenin.

Long-lasting behavioral effects in neonatal mice with multiple exposures to ketamine-xylazine anesthesia

PubMed Central

Huang, Lianyan; Hayes, Scott; Yang, Guang

2016-01-01

Anesthetic agents are often administered in the neonatal period, a time of rapid brain development and synaptogenesis. Mounting evidence suggests that anesthetics can disrupt neurocognitive development, particularly in cases of multiple or prolonged anesthetic exposure. Previous studies have shown that administering multiple doses of ketamine-xylazine (KX) anesthesia to neonatal mice can induce long-term changes to synaptic plasticity in the cortex, but the effect on neurocognitive function remains unclear. In this study, we exposed neonatal mice to single dose and multiple doses of KX anesthesia in the neonatal period (postnatal days 7, 9, 11), and conducted a series of behavioral tests in young adulthood (1 month of age). Mice receiving multiple doses of KX anesthesia showed deficits in novel object recognition, sociability, preference for social novelty and contextual fear response, but no effect on auditory-cued fear response. Single dose of KX anesthesia had no effect on these behaviors except for contextual fear response. We also observed that multiple exposures to KX anesthesia were associated with decreased CaMKII phosphorylation, which is known to play a role in synapse development and long-term potentiation, likely contributing to learning impairment. PMID:27622724

Structural and functional maturation of the developing primate brain.

PubMed

Levitt, Pat

2003-10-01

Descriptive studies have established that the developmental events responsible for the assembly of neural systems and circuitry are conserved across mammalian species. However, primates are unique regarding the time during which histogenesis occurs and the extended postnatal period during which myelination of pathways and circuitry formation occur and are then subsequently modified, particularly in the cerebral cortex. As in lower mammals, the framework for subcortical-cortical connectivity in primates is established before midgestation and already begins to remodel before birth. Association systems, responsible for modulating intracortical circuits that integrate information across functional domains, also form before birth, but their growth and reorganization extend into puberty. There are substantial differences across species in the patterns of development of specific neurochemical systems. The complexity is even greater when considering that the development of any particular cellular component may differ among cortical areas in the same primate species. Developmental and behavioral neurobiologists, psychologists, and pediatricians are challenged with understanding how functional maturation relates to the evolving anatomical organization of the human brain during childhood, and moreover, how genetic and environmental perturbations affect the adaptive changes exhibited by neural circuits in response to developmental disruption.

Deregulated Cardiac Specific MicroRNAs in Postnatal Heart Growth.

PubMed

Yu, Pujiao; Wang, Hongbao; Xie, Yuan; Zhou, Jinzhe; Yao, Jianhua; Che, Lin

2016-01-01

The heart is recognized as an organ that is terminally differentiated by adulthood. However, during the process of human development, the heart is the first organ with function in the embryo and grows rapidly during the postnatal period. MicroRNAs (miRNAs, miRs), as regulators of gene expression, play important roles during the development of multiple systems. However, the role of miRNAs in postnatal heart growth is still unclear. In this study, by using qRT-PCR, we compared the expression of seven cardiac- or muscle-specific miRNAs that may be related to heart development in heart tissue from mice at postnatal days 0, 3, 8, and 14. Four miRNAs-miR-1a-3p, miR-133b-3p, miR-208b-3p, and miR-206-3p-were significantly decreased while miR-208a-3p was upregulated during the postnatal heart growth period. Based on these results, GeneSpring GX was used to predict potential downstream targets by performing a 3-way comparison of predictions from the miRWalk, PITA, and microRNAorg databases. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis were used to identify potential functional annotations and signaling pathways related to postnatal heart growth. This study describes expression changes of cardiac- and muscle-specific miRNAs during postnatal heart growth and may provide new therapeutic targets for cardiovascular diseases.

Temporary Depletion of Microglia during the Early Postnatal Period Induces Lasting Sex-Dependent and Sex-Independent Effects on Behavior in Rats

PubMed Central

2016-01-01

Abstract Microglia are the primary immune cells of the brain and function in multiple ways to facilitate proper brain development. However, our current understanding of how these cells influence the later expression of normal behaviors is lacking. Using the laboratory rat, we administered liposomal clodronate centrally to selectively deplete microglia in the developing postnatal brain. We then assessed a range of developmental, juvenile, and adult behaviors. Liposomal clodronate treatment on postnatal days 0, 2, and 4 depleted microglia with recovery by about 10 days of age and induced a hyperlocomotive phenotype, observable in the second postnatal week. Temporary microglia depletion also increased juvenile locomotion in the open field test and decreased anxiety-like behaviors in the open field and elevated plus maze. These same rats displayed reductions in predator odor–induced avoidance behavior, but increased their risk assessment behaviors compared with vehicle-treated controls. In adulthood, postnatal microglia depletion resulted in significant deficits in male-specific sex behaviors. Using factor analysis, we identified two underlying traits—behavioral disinhibition and locomotion—as being significantly altered by postnatal microglia depletion. These findings further implicate microglia as being critically important to the development of juvenile and adult behavior. PMID:27957532

The von Economo neurons in frontoinsular and anterior cingulate cortex in great apes and humans.

PubMed

Allman, John M; Tetreault, Nicole A; Hakeem, Atiya Y; Manaye, Kebreten F; Semendeferi, Katerina; Erwin, Joseph M; Park, Soyoung; Goubert, Virginie; Hof, Patrick R

2010-06-01

The von Economo neurons (VENs) are large bipolar neurons located in frontoinsular (FI) and anterior cingulate cortex in great apes and humans, but not other primates. We performed stereological counts of the VENs in FI and LA (limbic anterior, a component of anterior cingulate cortex) in great apes and in humans. The VENs are more numerous in humans than in apes, although one gorilla approached the lower end of the human range. We also examined the ontological development of the VENs in FI and LA in humans. The VENs first appear in small numbers in the 36th week post-conception, are rare at birth, and increase in number during the first 8 months after birth. There are significantly more VENs in the right hemisphere than in the left in FI and LA in postnatal brains of apes and humans. This asymmetry in VEN numbers may be related to asymmetries in the autonomic nervous system. The activity of the inferior anterior insula, which contains FI, is related to physiological changes in the body, decision-making, error recognition, and awareness. The VENs appear to be projection neurons, although their targets are unknown. We made a preliminary study of the connections of FI cortex based on diffusion tensor imaging in the brain of a gorilla. The VEN-containing regions connect to the frontal pole as well as to other parts of frontal and insular cortex, the septum, and the amygdala. It is likely that the VENs in FI are projecting to some or all of these structures and relaying information related to autonomic control, decision-making, or awareness. The VENs selectively express the bombesin peptides neuromedin B (NMB) and gastrin releasing peptide (GRP) which are also expressed in another population of closely related neurons, the fork cells. NMB and GRP signal satiety. The genes for NMB and GRP are expressed selectively in small populations of neurons in the insular cortex in mice. These populations may be related to the VEN and fork cells and may be involved in the regulation of appetite. The loss of these cells may be related to the loss of satiety signaling in patients with frontotemporal dementia who have damage to FI. The VENs and fork cells may be morphological specializations of an ancient population of neurons involved in the control of appetite present in the insular cortex in all mammals. We found that the protein encoded by the gene DISC1 (disrupted in schizophrenia) is preferentially expressed by the VENs. DISC1 has undergone rapid evolutionary change in the line leading to humans, and since it suppresses dendritic branching it may be involved in the distinctive VEN morphology.

Posterior cortex epilepsy surgery in childhood and adolescence: Predictors of long-term seizure outcome.

PubMed

Ramantani, Georgia; Stathi, Angeliki; Brandt, Armin; Strobl, Karl; Schubert-Bast, Susanne; Wiegand, Gert; Korinthenberg, Rudolf; van Velthoven, Vera; Zentner, Josef; Schulze-Bonhage, Andreas; Bast, Thomas

2017-03-01

We aimed to investigate the long-term seizure outcome of children and adolescents who were undergoing epilepsy surgery in the parietooccipital cortex and determine their predictive factors. We retrospectively analyzed the data of 50 consecutive patients aged 11.1 (mean) ± 5.1 (standard deviation) years at surgery. All patients but one had a magnetic resonance imaging (MRI)-visible lesion. Resections were parietal in 40%, occipital in 32%, and parietooccipital in 28% cases; 24% patients additionally underwent a resection of the posterior border of the temporal lobe. Etiology included focal cortical dysplasia in 44%, benign tumors (dysembryoplastic neuroepithelial tumor, ganglioglioma, angiocentric glioma, and pilocystic astrocytoma) in 32%, peri- or postnatal ischemic lesions in 16%, and tuberous sclerosis in 8% cases. At last follow-up (mean 8 years, range 1.5-18 years), 60% patients remained seizure-free (Engel class I): 30% had discontinued and 20% had reduced antiepileptic drugs. Most seizure recurrences (71%) occurred within the first 6 months, and only three patients presented with seizures ≥2 years after surgery. Independent predictors of seizure recurrence included left-sided as well as parietal epileptogenic zones and resections. Longer epilepsy duration to surgery was identified as the only modifiable independent predictor of seizure recurrence. Our study demonstrates that posterior cortex epilepsy surgery is highly effective in terms of lasting seizure control and antiepileptic drug cessation in selected pediatric candidates. Most importantly, our data supports the early consideration of surgical intervention in children and adolescents with refractory posterior cortex epilepsy. Wiley Periodicals, Inc. © 2017 International League Against Epilepsy.

Gene expression of fatty acid transport and binding proteins in the blood-brain barrier and the cerebral cortex of the rat: differences across development and with different DHA brain status.

PubMed

Pélerin, Hélène; Jouin, Mélanie; Lallemand, Marie-Sylvie; Alessandri, Jean-Marc; Cunnane, Stephen C; Langelier, Bénédicte; Guesnet, Philippe

2014-11-01

Specific mechanisms for maintaining docosahexaenoic acid (DHA) concentration in brain cells but also transporting DHA from the blood across the blood-brain barrier (BBB) are not agreed upon. Our main objective was therefore to evaluate the level of gene expression of fatty acid transport and fatty acid binding proteins in the cerebral cortex and at the BBB level during the perinatal period of active brain DHA accretion, at weaning, and until the adult age. We measured by real time RT-PCR the mRNA expression of different isoforms of fatty acid transport proteins (FATPs), long-chain acyl-CoA synthetases (ACSLs), fatty acid binding proteins (FABPs) and the fatty acid transporter (FAT)/CD36 in cerebral cortex and isolated microvessels at embryonic day 18 (E18) and postnatal days 14, 21 and 60 (P14, P21 and P60, respectively) in rats receiving different n-3 PUFA dietary supplies (control, totally deficient or DHA-supplemented). In control rats, all the genes were expressed at the BBB level (P14 to P60), the mRNA levels of FABP5 and ACSL3 having the highest values. Age-dependent differences included a systematic decrease in the mRNA expressions between P14-P21 and P60 (2 to 3-fold), with FABP7 mRNA abundance being the most affected (10-fold). In the cerebral cortex, mRNA levels varied differently since FATP4, ACSL3 and ACSL6 and the three FABPs genes were highly expressed. There were no significant differences in the expression of the 10 genes studied in n-3 deficient or DHA-supplemented rats despite significant differences in their brain DHA content, suggesting that brain DHA uptake from the blood does not necessarily require specific transporters within cerebral endothelial cells and could, under these experimental conditions, be a simple passive diffusion process. Copyright © 2014 Elsevier Ltd. All rights reserved.

Brief exposure to methamphetamine (METH) and phencyclidine (PCP) during late development leads to long-term learning deficits in rats.

PubMed

White, Ilsun M; Minamoto, Takehiro; Odell, Joseph R; Mayhorn, Joseph; White, Wesley

2009-04-17

Exposure to methamphetamine (METH) and phencyclidine (PCP) during early development is thought to produce later behavioral deficits. We postulated that exposure to METH and PCP during later development would produce similar behavioral deficits, particularly learning deficits in adulthood. Wistar rats were treated with METH (9 mg/kg), PCP (9 mg/kg), or saline during later development, postnatal days (PD) 50-51, and subsequent behavioral changes were examined including: locomotor activity during the acute drug state (PD 50-51) and the post-drug phase (PD 50-80); social interaction on PD 54-80; and spatial discrimination and reversal in adulthood (after PD 90). METH and PCP differentially affected locomotion during the acute state, but not during the post-drug phase. METH decreased social interaction throughout tests two weeks after drug treatment, whereas PCP decreased social interaction only during the first 8 min of tests. Neither METH nor PCP impaired initial acquisition of spatial discrimination. However, reversal was significantly impaired by PCP, whereas METH produced a mild deficit, compared to controls. Our data provide evidence that exposure to PCP and METH during later development lead to enduring cognitive deficits in adulthood. Selective impairment of reversal may reflect neurological damage in the prefrontal cortex due to early exposure to drugs.

The extended trajectory of hippocampal development: implications for early memory development and disorder

PubMed Central

Gómez, Rebecca L.; Edgin, Jamie O.

2015-01-01

Hippocampus has an extended developmental trajectory, with refinements occurring in the trisynaptic circuit until adolescence. While structural change should suggest a protracted course in behavior, some studies find evidence of precocious hippocampal development in the first postnatal year and continuity in memory processes beyond. However, a number of memory functions, including binding and relational inference, can be cortically supported. Evidence from the animal literature suggests that tasks often associated with hippocampus (Visual Paired Comparison, binding of a visuomotor response) can be mediated by structures external to hippocampus. Thus, a complete examination of memory development will have to rule out cortex as a source of early memory competency. We propose that early memory must show properties associated with full function of the trisynaptic circuit to reflect “adult-like” memory function, mainly 1) rapid encoding of contextual details of overlapping patterns, and 2) retention of these details over sleep-dependent delays. A wealth of evidence suggests that these functions are not apparent until 18–24 months, with behavioral discontinuities reflecting shifts in the neural structures subserving memory beginning approximately at this point in development. We discuss the implications of these observations for theories of memory and for identifying and measuring memory function in populations with typical and atypical hippocampal function. PMID:26437910

Novel homozygous missense mutation in ALDH7A1 causes neonatal pyridoxine dependent epilepsy.

PubMed

Coci, Emanuele G; Codutti, Luca; Fink, Christian; Bartsch, Sophie; Grüning, Gunnar; Lücke, Thomas; Kurth, Ingo; Riedel, Joachim

2017-04-01

Pyridoxine dependent epilepsy (PDE) (OMIM#266100) is a neonatal form of epilepsy, caused by dysfunction of the enzyme α-aminoadipic semialdehyde dehydrogenase (ALDH7A1 or Antiquitin). This enzyme converts α-aminoadipic semialdehyde (α-AASA) into α-aminoadipate (AAA), a critical step in the lysine metabolism of the brain. ALDH7A1 dysfunction causes an accumulation of α-AASA and δ 1 -piperideine-6-carboxylic acid (P6C), which are in equilibrium with each other. P6C binds and inactivates pyridoxal 5'-phosphate (PLP), the active form of pyridoxine. Individuals affected by ALDH7A1 deficiency show pre-natal and post-natal seizures, which respond to oral pyridoxine but not to other pediatric anti-epileptic drugs. We discovered a novel missense mutation (c.566G > A, p.Gly189Glu) in homozygous state residing in the NAD+ binding domain coding region of exon 6 and affecting an highly conserved amino acid residue. The seizures stopped under post-natal pyridoxine therapy, nevertheless a longer follow-up is needed to evaluate the intellectual development of the child, who is additionally treated with oral l-arginine since the 13th month of life. Developmental delay with or without structural cortex abnormalities were reported in several patients. A brain MRI scan revealed hyperintense white matter in the right cerebellum compatible with cerebellar gliosis. Taken together, our studies enlarge the group of missense pathogenic mutations of ALDH7A1 gene and reveal a novel cerebellar finding within the PDE patients cohort. Copyright © 2016 Elsevier Ltd. All rights reserved.

Effects of postnatal ethanol exposure at different developmental phases on neurotrophic factors and phosphorylated proteins on signal transductions in rat brain.

PubMed

Tsuji, Ryozo; Fattori, Vittorio; Abe, Shin-ichi; Costa, Lucio G; Kobayashi, Kumiko

2008-01-01

Exposure to ethanol during development induces severe brain damage resulting in a number of CNS dysfunctions including microencephaly and mental retardation in humans and in laboratory animals. The most vulnerable period to ethanol neurotoxicity coincides with the peak of brain growth spurt. Recently, neurotrophic factors and/or their signal transduction pathways have been reported as a potential relevant target for the developmental neurotoxicity of ethanol. The present studies were designed to investigate the effects of ethanol given in various developmental phases during the brain growth spurt in rats. Rat pups were assigned to the three treatment groups and treated with 5 g/kg of ethanol for three days, on postnatal days (PND) 2-4, 6-8 or 13-15. Whole brain weights were reduced only in the PND 6-8 group concurrently with the reduction of GDNF mRNA in cortex in this group. BDNF mRNA expression was reduced in both the PND 6-8 and 13-15 groups, while mRNA expressions of NT-3 and NGF were unchanged in all three groups. Phospho-Akt level was mostly reduced in the PND 6-8 group. Both phospho-MAPK and p-70S6 kinase levels were decreased in all groups whereas no changes were observed in either phospho-PKCzeta or CREB level. The phosphorylation of Akt was immediately inhibited after single administration of ethanol, and its inhibition was correlated with variations in blood ethanol concentration. These findings suggest that GDNF and the phosphorylation of Akt play a possible key role in the ethanol-induced developmental neurotoxicity.

Patterns of Spontaneous Local Network Activity in Developing Cerebral Cortex: Relationship to Adult Cognitive Function.

PubMed

Peinado, Alejandro; Abrams, Charles K

2015-01-01

Detecting neurodevelopμental disorders of cognition at the earliest possible stages could assist in understanding them mechanistically and ultimately in treating them. Finding early physiological predictors that could be visualized with functional neuroimaging would represent an important advance in this regard. We hypothesized that one potential source of physiological predictors is the spontaneous local network activity prominent during specific periods in development. To test this we used calcium imaging in brain slices and analyzed variations in the frequency and intensity of this early activity in one area, the entorhinal cortex (EC), in order to correlate early activity with level of cognitive function later in life. We focused on EC because of its known role in different types of cognitive processes and because it is an area where spontaneous activity is prominent during early postnatal development in rodent models of cortical development. Using rat strains (Long-Evans, Wistar, Sprague-Dawley and Brattleboro) known to differ in cognitive performance in adulthood we asked whether neonatal animals exhibit corresponding strain-related differences in EC spontaneous activity. Our results show significant differences in this activity between strains: compared to a high cognitive-performing strain, we consistently found an increase in frequency and decrease in intensity in neonates from three lower performing strains. Activity was most different in one strain considered a model of schizophrenia-like psychopathology. While we cannot necessarily infer a causal relationship between early activity and adult cognition our findings suggest that the pattern of spontaneous activity in development could be an early predictor of a developmental trajectory advancing toward sub-optimal cognitive performance in adulthood. Our results further suggest that the strength of dopaminergic signaling, by setting the balance between excitation and inhibition, is a potential underlying mechanism that could explain the observed differences in early spontaneous activity patterns.

Neonatal treatment with monosodium glutamate lastingly facilitates spreading depression in the rat cortex.

PubMed

Lima, Cássia Borges; Soares, Geórgia de Sousa Ferreira; Vitor, Suênia Marcele; Castellano, Bernardo; Andrade da Costa, Belmira Lara da Silveira; Guedes, Rubem Carlos Araújo

2013-09-17

Monosodium glutamate (MSG) is a neuroexcitatory amino acid used in human food to enhance flavor. MSG can affect the morphological and electrophysiological organization of the brain. This effect is more severe during brain development. Here, we investigated the electrophysiological and morphological effects of MSG in the developing rat brain by characterizing changes in the excitability-related phenomenon of cortical spreading depression (CSD) and microglial reaction. From postnatal days 1-14, Wistar rat pups received 2 or 4 g/kg MSG (groups MSG-2 and MSG-4, respectively; n=9 in each group), saline (n=10) or no treatment (naïve group; n=5) every other day. At 45-60 days, CSD was recorded on two cortical points for 4h. The CSD parameters velocity, and amplitude and duration of the negative potential change were calculated. Fixative-perfused brain sections were immunolabeled with anti-IBA-1 antibodies to identify and quantify cortical microglia. MSG-4 rats presented significantly higher velocities (4.59 ± 0.34 mm/min) than the controls (saline, 3.84 ± 0.20mm/min; naïve, 3.71 ± 0.8mm/min) and MSG-2 group (3.75 ± 0.10mm/min). The amplitude (8.8 ± 2.2 to 11.2 ± 1.9 mV) and duration (58.2 ± 7.1 to 73.6 ± 6.0s) of the negative slow potential shift was similar in all groups. MSG-treatment dose-dependently increased the microglial immunolabeling. The results demonstrate a novel, dose-dependent action of MSG in the developing brain, characterized by acceleration of CSD and significant microglial reaction in the cerebral cortex. The CSD effect indicates that MSG can influence cortical excitability, during brain development, as evaluated by CSD acceleration. Data suggest caution when consuming MSG, especially in developing organisms. © 2013.

Repeated intermittent alcohol exposure during the third trimester-equivalent increases expression of the GABA(A) receptor δ subunit in cerebellar granule neurons and delays motor development in rats.

PubMed

Diaz, Marvin R; Vollmer, Cyndel C; Zamudio-Bulcock, Paula A; Vollmer, William; Blomquist, Samantha L; Morton, Russell A; Everett, Julie C; Zurek, Agnieszka A; Yu, Jieying; Orser, Beverley A; Valenzuela, C Fernando

2014-04-01

Exposure to ethanol (EtOH) during fetal development can lead to long-lasting alterations, including deficits in fine motor skills and motor learning. Studies suggest that these are, in part, a consequence of cerebellar damage. Cerebellar granule neurons (CGNs) are the gateway of information into the cerebellar cortex. Functionally, CGNs are heavily regulated by phasic and tonic GABAergic inhibition from Golgi cell interneurons; however, the effect of EtOH exposure on the development of GABAergic transmission in immature CGNs has not been investigated. To model EtOH exposure during the 3rd trimester-equivalent of human pregnancy, neonatal pups were exposed intermittently to high levels of vaporized EtOH from postnatal day (P) 2 to P12. This exposure gradually increased pup serum EtOH concentrations (SECs) to ∼60 mM (∼0.28 g/dl) during the 4 h of exposure. EtOH levels gradually decreased to baseline 8 h after the end of exposure. Surprisingly, basal tonic and phasic GABAergic currents in CGNs were not significantly affected by postnatal alcohol exposure (PAE). However, PAE increased δ subunit expression at P28 as detected by immunohistochemical and western blot analyses. Also, electrophysiological studies with an agonist that is highly selective for δ-containing GABA(A) receptors, 4,5,6,7-tetrahydroisoxazolo[4,5-c]pyridine-3-ol (THIP), showed an increase in THIP-induced tonic current. Behavioral studies of PAE rats did not reveal any deficits in motor coordination, except for a delay in the acquisition of the mid-air righting reflex that was apparent at P15 to P18. These findings demonstrate that repeated intermittent exposure to high levels of EtOH during the equivalent of the last trimester of human pregnancy has significant but relatively subtle effects on motor coordination and GABAergic transmission in CGNs in rats. Copyright © 2013 Elsevier Ltd. All rights reserved.

Differential ontogenetic patterns of levocabastine-sensitive neurotensin NT2 receptors and of NT1 receptors in the rat brain revealed by in situ hybridization.

PubMed

Lépée-Lorgeoux, I; Betancur, C; Rostène, W; Pélaprat, D

1999-03-12

The postnatal ontogeny of the levocabastine-sensitive neurotensin receptor (NT2) mRNA was studied by in situ hybridization in the rat brain and compared with the distribution of the levocabastine-insensitive NT1 receptor. NT2 receptor mRNA was absent at birth from all brain structures except the ependymal cell layer lining the ventricles. The development of NT2 receptor mRNA followed three ontogenetic patterns. The first pattern, involving the majority of the cerebral gray matter, was characterized by a continuous increase from postnatal day 5 (P5) to P30. The second one, involving regions rich in myelinated fibers such as the corpus callosum and lacunosum moleculare layer of the hippocampus, exhibited a pronounced increase between P5 and P10, peaked at P15 and was followed by a plateau or a slight decrease. The third pattern was observed in the ependymal cell layer lining the olfactory and lateral ventricles, where the high labeling already present at birth continued to increase during development. These different developmental patterns could reflect the variety of cells expressing NT2 receptor mRNA, including neurons, protoplasmic astrocytes in gray matter, fibrous astrocytes present in myelinated fibers tracts, and ependymal cells. In contrast, NT1 receptor mRNA, which seems to be associated only with neurons, was highly and transiently expressed during the perinatal period in the cerebral cortex, hippocampus and striatal neuroepithelium. Other regions, notably the ventral tegmental area and substantia nigra compacta, exhibited a gradual increase in NT1 receptor signal, reaching adult levels by P21. Both the differential localization and ontogenetic profiles of NT1 and NT2 receptor mRNAs suggest different involvement of these two receptors in brain functions and development. Copyright 1999 Elsevier Science B.V.

Supplementation with fish oil and coconut fat prevents prenatal stress-induced changes in early postnatal development.

PubMed

Borsonelo, Elizabethe C; Suchecki, Deborah; Calil, Helena Maria; Galduróz, José Carlos F

2011-08-01

Adequate development of the central nervous system depends on prenatal and postnatal factors. On one hand, prenatal stress (PNS) has been implicated in impaired development of the offspring. On other hand, nutritional factors during pregnancy and lactation can influence fetal and postnatal growth. This study assessed the postnatal development of rat offspring exposed to PNS, which consisted of restraint and bright lights, 3 times/day, from days 14 to 20 of pregnancy, whose mothers were fed different diets during pregnancy and lactation: regular diet, diet supplemented with coconut fat or fish oil. When pregnancy was confirmed, they were distributed into control (CTL) or PNS groups. At birth, PNS males and females weighed less than those in the group CTL. At 21 days of age, this alteration was no longer observed with fish oil and coconut fat groups. PNS and coconut fat diet induced increased locomotor activity in 13 day old male and female pups, and this effect was prevented by fish oil supplementation only in females. In conclusion, postnatal development from birth to weaning was influenced by PNS and diet and some of those alterations were prevented by coconut fat and fish oil. Copyright © 2011 ISDN. Published by Elsevier Ltd. All rights reserved.

Testosterone selectively increases primary follicles in ovarian cortex grafted onto embryonic chick membranes: relevance to polycystic ovaries.

PubMed

Qureshi, A I; Nussey, S S; Bano, G; Musonda, P; Whitehead, S A; Mason, H D

2008-08-01

Histological studies have demonstrated that polycystic ovaries (PCO) contain increased numbers of preantral follicles with a specific increase in primary follicles. Polycystic ovary syndrome is associated with hyperandrogenism and pre- and postnatal androgenization of primates increases the pool of growing follicles producing changes resembling PCO. In vitro studies could test the hypothesis that androgens alter early folliculogenesis, but conventional culture techniques for small follicles are generally unsuitable in non-rodent species. Our objective was to develop and use a method to investigate the effects of testosterone on early folliculogenesis. We adapted an in ovo technique in which lamb cortical ovarian fragments were grafted onto the chorioallantoic membrane of fertilised chick eggs. Optimal experimental conditions for vascularisation and survival of tissue were determined and the model then used to investigate the effects of testosterone on follicle growth. Eggs were inoculated with testosterone at the time of implantation of the ovarian tissue, which was retrieved 5 days later. Tissue was sectioned and follicles staged and counted. There was no wholesale initiation of primordial follicle growth over the 5-day in ovo culture. Importantly, the proportion of primordial, primary and secondary follicles remained similar to those in unimplanted tissue. Testosterone increased the number of primary follicles by 50% compared with controls, an effect that was largely due to a reduction in atresia. In conclusion, incubation of ovarian cortex with testosterone reproduces the changes in early folliculogenesis reported in histological studies of PCO.

Upregulation of cholesterol 24-hydroxylase following hypoxia-ischemia in neonatal mouse brain.

PubMed

Lu, Fuxin; Zhu, Jun; Guo, Selena; Wong, Brandon J; Chehab, Farid F; Ferriero, Donna M; Jiang, Xiangning

2018-06-01

BackgroundMaintenance of cholesterol homeostasis is crucial for brain development. Brain cholesterol relies on de novo synthesis and is cleared primarily by conversion to 24S-hydroxycholesterol (24S-HC) with brain-specific cholesterol 24-hydroxylase (CYP46A1). We aimed to investigate the impact of hypoxia-ischemia (HI) on brain cholesterol metabolism in the neonatal mice.MethodsPostnatal day 9 C57BL/6 pups were subjected to HI using the Vannucci model. CYP46A1 expression was assessed with western blotting and its cellular localization was determined using immunofluorescence staining. The amount of brain cholesterol, 24S-HC in the cortex and in the serum, was measured with enzyme-linked immunosorbent assay (ELISA).ResultsThere was a transient cholesterol loss at 6 h after HI. CYP46A1 was significantly upregulated at 6 and 24 h following HI with a concomitant increase of 24S-HC in the ipsilateral cortex and in the serum. The serum levels of 24S-HC correlated with those in the brain, as well as with necrotic and apoptotic cell death evaluated by the expression of spectrin breakdown products and cleaved caspase-3 at 6 and 24 h after HI.ConclusionEnhanced cholesterol turnover by activation of CYP46A1 represents disrupted brain cholesterol homeostasis early after neonatal HI. 24S-HC might be a novel blood biomarker for severity of hypoxic-ischemic encephalopathy with potential clinical application.

Endothelial cell-derived GABA signaling modulates neuronal migration and postnatal behavior

PubMed Central

Li, Suyan; Kumar T, Peeyush; Joshee, Sampada; Kirschstein, Timo; Subburaju, Sivan; Khalili, Jahan S; Kloepper, Jonas; Du, Chuang; Elkhal, Abdallah; Szabó, Gábor; Jain, Rakesh K; Köhling, Rüdiger; Vasudevan, Anju

2018-01-01

The cerebral cortex is essential for integration and processing of information that is required for most behaviors. The exquisitely precise laminar organization of the cerebral cortex arises during embryonic development when neurons migrate successively from ventricular zones to coalesce into specific cortical layers. While radial glia act as guide rails for projection neuron migration, pre-formed vascular networks provide support and guidance cues for GABAergic interneuron migration. This study provides novel conceptual and mechanistic insights into this paradigm of vascular-neuronal interactions, revealing new mechanisms of GABA and its receptor-mediated signaling via embryonic forebrain endothelial cells. With the use of two new endothelial cell specific conditional mouse models of the GABA pathway (Gabrb3ΔTie2-Cre and VgatΔTie2-Cre), we show that partial or complete loss of GABA release from endothelial cells during embryogenesis results in vascular defects and impairs long-distance migration and positioning of cortical interneurons. The downstream effects of perturbed endothelial cell-derived GABA signaling are critical, leading to lasting changes to cortical circuits and persistent behavioral deficits. Furthermore, we illustrate new mechanisms of activation of GABA signaling in forebrain endothelial cells that promotes their migration, angiogenesis and acquisition of blood-brain barrier properties. Our findings uncover and elucidate a novel endothelial GABA signaling pathway in the CNS that is distinct from the classical neuronal GABA signaling pathway and shed new light on the etiology and pathophysiology of neuropsychiatric diseases, such as autism spectrum disorders, epilepsy, anxiety, depression and schizophrenia. PMID:29086765

Segregation of feedforward and feedback projections in mouse visual cortex

PubMed Central

Berezovskii, Vladimir K.; Nassi, Jonathan J.; Born, Richard T.

2011-01-01

Hierarchical organization is a common feature of mammalian neocortex. Neurons that send their axons from lower to higher areas of the hierarchy are referred to as “feedforward” (FF) neurons, whereas those projecting in the opposite direction are called “feedback” (FB) neurons. Anatomical, functional and theoretical studies suggest that these different classes of projections play fundamentally different roles in perception. In primates, laminar differences in projection patterns often distinguish the two projection streams. In rodents, however, these differences are less clear, despite an established hierarchy of visual areas. Thus the rodent provides a strong test of the hypothesis that FF and FB neurons form distinct populations. We tested this hypothesis by injecting retrograde tracers into two different hierarchical levels of mouse visual cortex (areas 17 and AL) and then determining the relative proportions of double-labeled FB and FF neurons in an area intermediate to them (LM). Despite finding singly labeled neurons densely intermingled with no laminar segregation, we found few double-labeled neurons (~5% of each singly labeled population). We also examined the development of FF and FB connections. FF connections were present at the earliest time-point we examined (postnatal day two, P2), while FB connections were not detectable until P11. Our findings indicate that, even in cortices without laminar segregation of FF and FB neurons, the two projection systems are largely distinct at the neuronal level and also differ with respect to the timing of their outgrowth. PMID:21618232

Neurochemical changes following a single dose of polybrominated diphenyl ether 47 in mice.

PubMed

Gee, Jillian R; Moser, Virginia C; McDanie, Katherine L; Herr, David W

2011-04-01

Polybrominated diphenyl ethers (PBDEs) are commonly used as commercial flame retardants in a variety of products, including plastics and textiles. Previous studies in our laboratory, and in the literature, showed that exposure to a specific PBDE congener (PBDE 47) during a critical period of brain development may lead to developmental delays and hyperactivity in adulthood. To date, the underlying causes of these behavioral alterations are unknown, although in vitro studies linked PBDEs with potential alterations in neurotransmitter levels, particularly acetylcholine (ACh) and dopamine (DA). Alterations in DA function have also been noted in cases of hyperactivity in rodents and humans. The current study examined monoamine levels in male mice acutely exposed to corn oil vehicle or PBDE 47 (1, 10, or 30 mg/kg) on postnatal day (PND) 10. Animals were sacrificed on PND 15, PND 20, and in adulthood (131-159 days old). The cortex, striatum, and cerebellum were isolated and analyzed by high-performance liquid chromatography to determine the concentration of monoamines within each brain region. A statistically significant increase in DA levels was seen within the cortex, regardless of age, but only in the 10-mg/kg PBDE treatment group. While these effects did not show a monotonic dose response, we previously reported hyperactivity in littermates in the same dose group, but not at the lower or higher dose. Thus, early developmental exposure to PBDE 47 alters the levels of cortical DA in male mice, which may correlate with behavioral observations in littermates.

Early Social Isolation Stress and Perinatal NMDA Receptor Antagonist Treatment Induce Changes in the Structure and Neurochemistry of Inhibitory Neurons of the Adult Amygdala and Prefrontal Cortex.

PubMed

Castillo-Gómez, Esther; Pérez-Rando, Marta; Bellés, María; Gilabert-Juan, Javier; Llorens, José Vicente; Carceller, Héctor; Bueno-Fernández, Clara; García-Mompó, Clara; Ripoll-Martínez, Beatriz; Curto, Yasmina; Sebastiá-Ortega, Noelia; Moltó, María Dolores; Sanjuan, Julio; Nacher, Juan

2017-01-01

The exposure to aversive experiences during early life influences brain development and leads to altered behavior. Moreover, the combination of these experiences with subtle alterations in neurodevelopment may contribute to the emergence of psychiatric disorders, such as schizophrenia. Recent hypotheses suggest that imbalances between excitatory and inhibitory (E/I) neurotransmission, especially in the prefrontal cortex and the amygdala, may underlie their etiopathology. In order to understand better the neurobiological bases of these alterations, we studied the impact of altered neurodevelopment and chronic early-life stress on these two brain regions. Transgenic mice displaying fluorescent excitatory and inhibitory neurons, received a single injection of MK801 (NMDAR antagonist) or vehicle solution at postnatal day 7 and/or were socially isolated from the age of weaning until adulthood (3 months old). We found that anxiety-related behavior, brain volume, neuronal structure, and the expression of molecules related to plasticity and E/I neurotransmission in adult mice were importantly affected by early-life stress. Interestingly, many of these effects were potentiated when the stress paradigm was applied to mice perinatally injected with MK801 ("double-hit" model). These results clearly show the impact of early-life stress on the adult brain, especially on the structure and plasticity of inhibitory networks, and highlight the double-hit model as a valuable tool to study the contribution of early-life stress in the emergence of neurodevelopmental psychiatric disorders, such as schizophrenia.

Construction of 4D high-definition cortical surface atlases of infants: Methods and applications.

PubMed

Li, Gang; Wang, Li; Shi, Feng; Gilmore, John H; Lin, Weili; Shen, Dinggang

2015-10-01

In neuroimaging, cortical surface atlases play a fundamental role for spatial normalization, analysis, visualization, and comparison of results across individuals and different studies. However, existing cortical surface atlases created for adults are not suitable for infant brains during the first two postnatal years, which is the most dynamic period of postnatal structural and functional development of the highly-folded cerebral cortex. Therefore, spatiotemporal cortical surface atlases for infant brains are highly desired yet still lacking for accurate mapping of early dynamic brain development. To bridge this significant gap, leveraging our infant-dedicated computational pipeline for cortical surface-based analysis and the unique longitudinal infant MRI dataset acquired in our research center, in this paper, we construct the first spatiotemporal (4D) high-definition cortical surface atlases for the dynamic developing infant cortical structures at seven time points, including 1, 3, 6, 9, 12, 18, and 24 months of age, based on 202 serial MRI scans from 35 healthy infants. For this purpose, we develop a novel method to ensure the longitudinal consistency and unbiasedness to any specific subject and age in our 4D infant cortical surface atlases. Specifically, we first compute the within-subject mean cortical folding by unbiased groupwise registration of longitudinal cortical surfaces of each infant. Then we establish longitudinally-consistent and unbiased inter-subject cortical correspondences by groupwise registration of the geometric features of within-subject mean cortical folding across all infants. Our 4D surface atlases capture both longitudinally-consistent dynamic mean shape changes and the individual variability of cortical folding during early brain development. Experimental results on two independent infant MRI datasets show that using our 4D infant cortical surface atlases as templates leads to significantly improved accuracy for spatial normalization of cortical surfaces across infant individuals, in comparison to the infant surface atlases constructed without longitudinal consistency and also the FreeSurfer adult surface atlas. Moreover, based on our 4D infant surface atlases, for the first time, we reveal the spatially-detailed, region-specific correlation patterns of the dynamic cortical developmental trajectories between different cortical regions during early brain development. Copyright © 2015 Elsevier B.V. All rights reserved.

APC/CCdh1-Rock2 pathway controls dendritic integrity and memory

PubMed Central

Bobo-Jiménez, Verónica; Delgado-Esteban, María; Angibaud, Julie; Sánchez-Morán, Irene; de la Fuente, Antonio; Yajeya, Javier; Nägerl, U. Valentin; Castillo, José; Bolaños, Juan P.

2017-01-01

Disruption of neuronal morphology contributes to the pathology of neurodegenerative disorders such as Alzheimer’s disease (AD). However, the underlying molecular mechanisms are unknown. Here, we show that postnatal deletion of Cdh1, a cofactor of the anaphase-promoting complex/cyclosome (APC/C) ubiquitin ligase in neurons [Cdh1 conditional knockout (cKO)], disrupts dendrite arborization and causes dendritic spine and synapse loss in the cortex and hippocampus, concomitant with memory impairment and neurodegeneration, in adult mice. We found that the dendrite destabilizer Rho protein kinase 2 (Rock2), which accumulates in the brain of AD patients, is an APC/CCdh1 substrate in vivo and that Rock2 protein and activity increased in the cortex and hippocampus of Cdh1 cKO mice. In these animals, inhibition of Rock activity, using the clinically approved drug fasudil, prevented dendritic network disorganization, memory loss, and neurodegeneration. Thus, APC/CCdh1-mediated degradation of Rock2 maintains the dendritic network, memory formation, and neuronal survival, suggesting that pharmacological inhibition of aberrantly accumulated Rock2 may be a suitable therapeutic strategy against neurodegeneration. PMID:28396402

The von Economo neurons in fronto-insular and anterior cingulate cortex

PubMed Central

Allman, John M.; Tetreault, Nicole A.; Hakeem, Atiya Y.; Manaye, Kebreten F.; Semendeferi, Katerina; Erwin, Joseph M.; Park, Soyoung; Goubert, Virginie; Hof, Patrick R.

2011-01-01

The von Economo neurons (VENs) are large bipolar neurons located in fronto-insular cortex (FI) and anterior limbic area (LA) in great apes and humans but not in other primates. Our stereological counts of VENs in FI and LA show them to be more numerous in humans than in apes. In humans, small numbers of VENs appear the 36th week post conception, with numbers increasing during the first eight months after birth. There are significantly more VENs in the right hemisphere in postnatal brains; this may be related to asymmetries in the autonomic nervous system. VENs are also present in elephants and whales and may be a specialization related to very large brain size. The large size and simple dendritic structure of these projection neurons suggest that they rapidly send basic information from FI and LA to other parts of the brain, while slower neighboring pyramids send more detailed information. Selective destruction of VENs in early stages of fronto-temporal dementia implies that they are involved in empathy, social awareness, and self-control, consistent with evidence from functional imaging. PMID:21534993

Alterations in apoptotic caspases and antioxidant enzymes in arsenic exposed rat brain regions: reversal effect of essential metals and a chelating agent.

PubMed

Kadeyala, Praveen Kumar; Sannadi, Saritha; Gottipolu, Rajarami Reddy

2013-11-01

Arsenic (As) widely studied for its effects as a neurotoxicant. The present study was designed to evaluate the protective effect of calcium, zinc or monoisoamyl dimercaptosuccinic acid (MiADMSA), either individually or in combination on As induced oxidative stress and apoptosis in brain regions (cerebral cortex, hippocampus and cerebellum) of postnatal day (PND) 21, 28 and 3 months old rats. Arsenic exposure significantly decreased the activities of superoxide dismutase (SOD) isoforms, catalase (CAT), glutathione peroxidase (GPx) and glutathione reductase (GR) with increase in glutathione s transferase (GST) while lipid peroxidation (LPx), arsenic levels, mRNA expression of caspase 3 and 9 were significantly increased in different brain regions. Arsenic induced alterations in these parameters were greater in PND 28 and more pronounced in cerebral cortex. From the results it is evident that combined supplementation of calcium and zinc along with MiADMSA would be most effective compared to individual administration in reducing arsenic induced neurotoxicity. Copyright © 2013. Published by Elsevier B.V.

Early postnatal exposure to isoflurane causes cognitive deficits and disrupts development of newborn hippocampal neurons via activation of the mTOR pathway

PubMed Central

Lim, Sanghee; Kwak, Minhye; Gray, Christy D.; Xu, Michael; Choi, Jun H.; Junn, Sue; Kim, Jieun; Xu, Jing; Schaefer, Michele; Johns, Roger A.; Song, Hongjun; Ming, Guo-Li; Mintz, C. David

2017-01-01

Clinical and preclinical studies indicate that early postnatal exposure to anesthetics can lead to lasting deficits in learning and other cognitive processes. The mechanism underlying this phenomenon has not been clarified and there is no treatment currently available. Recent evidence suggests that anesthetics might cause persistent deficits in cognitive function by disrupting key events in brain development. The hippocampus, a brain region that is critical for learning and memory, contains a large number of neurons that develop in the early postnatal period, which are thus vulnerable to perturbation by anesthetic exposure. Using an in vivo mouse model we demonstrate abnormal development of dendrite arbors and dendritic spines in newly generated dentate gyrus granule cell neurons of the hippocampus after a clinically relevant isoflurane anesthesia exposure conducted at an early postnatal age. Furthermore, we find that isoflurane causes a sustained increase in activity in the mechanistic target of rapamycin pathway, and that inhibition of this pathway with rapamycin not only reverses the observed changes in neuronal development, but also substantially improves performance on behavioral tasks of spatial learning and memory that are impaired by isoflurane exposure. We conclude that isoflurane disrupts the development of hippocampal neurons generated in the early postnatal period by activating a well-defined neurodevelopmental disease pathway and that this phenotype can be reversed by pharmacologic inhibition. PMID:28683067

CREB binding protein is required for both short-term and long-term memory formation.

PubMed

Chen, Guiquan; Zou, Xiaoyan; Watanabe, Hirotaka; van Deursen, Jan M; Shen, Jie

2010-09-29

CREB binding protein (CBP) is a transcriptional coactivator with histone acetyltransferase activity. Our prior study suggested that CBP might be a key target of presenilins in the regulation of memory formation and neuronal survival. To elucidate the role of CBP in the adult brain, we generated conditional knock-out (cKO) mice in which CBP is completely inactivated in excitatory neurons of the postnatal forebrain. Histological analysis revealed normal neuronal morphology and absence of age-dependent neuronal degeneration in the CBP cKO cerebral cortex. CBP cKO mice exhibited robust impairment in the formation of spatial, associative, and object-recognition memory. In addition to impaired long-term memory, CBP cKO mice also displayed deficits in short-term associative and object-recognition memory. Administration of a histone deacetylase inhibitor, trichostatin A, rescued the reduction of acetylated histones in the CBP cKO cortex but failed to rescue either short- or long-term memory deficits, suggesting that the memory impairment may not be caused by general reduction of histone acetyltransferase activity in CBP cKO mice. Further microarray and Western analysis showed decreased expression of calcium-calmodulin-dependent kinase isoforms and NMDA and AMPA receptor subunits in the cerebral cortex of CBP cKO mice. Collectively, these findings suggest a crucial role for CBP in the formation of both short- and long-term memory.

Histogenesis of the epithelial component of rat thymus: an ultrastructural and immunohistological analysis.

PubMed

Vicente, A; Varas, A; Sacedón, R; Zapata, A G

1996-04-01

Despite the assumed importance of thymic cell microenvironments for governing T-cell maturation, little is known about the ontogeny of their cell components. A few studies have analyzed previously the ontogenetical development of rat thymic epithelium (Bogojevic et al. 1990. Period. Biol., 92:126; Kampinga and Aspinall 1990 Harwood Acad. Pub., London, pp. 149-186; Micic et al., 1991 Dev. Comp. Immunol., 15:443-450) and recently we have reported the development of both interdigitating/dendritic cells and macrophages (Vicente et al., 1994 Immunology, 82:75-81, 1995 Immunology, 85:99-105). In the present work we analyze in situ ultrastructural, immunohistochemical, and histoenzymatically the appearance and development of the thymic epithelial cell component in both embryonic and neonatal Wistar rats with special emphasis on the origin of the different epithelial cell types, the occurrence or absence of a common precursor for these, and the expression of MHC molecules. The thymic primordium of 13-day-old embryos is formed by a homogeneous population of primitive epithelial cells differentiating gradually into various epithelial cell subtypes of both the cortex and the medulla. In the cortex, subcapsular and stroma-supporting epithelial cells appear at days 14-15 as two structurally different cell entities. At the same time, stroma-supporting, keratinized, and vacuolated epithelial cells occur in the thymic medulla. These last two cell types differentiate subsequently into Hassall's bodies and hypertrophied cells. Lympho-epithelial cell complexes are identified in the deep cortex around birth, when the cortical parenchyma houses a transitional erythropoiesis. mAbs (His-39, RMC-20) which recognize medullary epithelial cells in the adult thymus stain positively cells of the thymic primordium as early as day 16 of embryonic life. Cortical epithelial cell markers (His-37, RMC-17) appear, however, slightly later and the subcapsulary region is not established until postnatal life. MHC class I and class II molecules can be identified on epithelial cells in the thymus of 15-day-old embryonic rats although they reach the highest expression around birth. Our results confirm the heterogeneity of the thymic epithelial component, the persistence of primitive, non-differentiated epithelial cells morphologically similar to those occurring in the early thymic primordium in adult thymus, and the mutual relevance of epithelial cells and thymocytes for an adequate development of rat thymus gland.

Intestinal absorption and renal reabsorption of calcium throughout postnatal development

PubMed Central

Beggs, Megan R

2017-01-01

Calcium is vital for many physiological functions including bone mineralization. Postnatal deposition of calcium into bone is greatest in infancy and continues through childhood and adolescence until peek mineral density is reached in early adulthood. Thereafter, bone mineral density remains static until it eventually declines in later life. A positive calcium balance, i.e. more calcium absorbed than excreted, is crucial to bone deposition during growth and thus to peek bone mineral density. Dietary calcium is absorbed from the intestine into the blood. It is then filtered by the renal glomerulus and either reabsorbed by the tubule or excreted in the urine. Calcium can be (re)absorbed across intestinal and renal epithelia via both transcellular and paracellular pathways. Current evidence suggests that significant intestinal and renal calcium transport changes occur throughout development. However, the molecular details of these alterations are incompletely delineated. Here we first briefly review the current model of calcium transport in the intestine and renal tubule in the adult. Then, we describe what is known with regard to calcium handling through postnatal development, and how alterations may aid in mediating a positive calcium balance. The role of transcellular and paracellular calcium transport pathways and the contribution of specific intestinal and tubular segments vary with age. However, the current literature highlights knowledge gaps in how specifically intestinal and renal calcium (re)absorption occurs early in postnatal development. Future research should clarify the specific changes in calcium transport throughout early postnatal development including mediators of these alterations enabling appropriate bone mineralization. Impact statement This mini review outlines the current state of knowledge pertaining to the molecules and mechanisms maintaining a positive calcium balance throughout postnatal development. This process is essential to achieving optimal bone mineral density in early adulthood, thereby lowering the lifetime risk of osteoporosis. PMID:28346014

Couple comorbidity and correlates of postnatal depressive symptoms in mothers and fathers in the first two weeks following delivery.

PubMed

Anding, Jana Eos; Röhrle, Bernd; Grieshop, Melita; Schücking, Beate; Christiansen, Hanna

2016-01-15

Postnatal depression affects a significant number of parents; however, its co-occurrence in mothers and fathers has not been studied extensively. Identifying predictors and correlates of postnatal depressive symptoms can help develop effective interventions. Questionnaires on several socio-demographic and psychosocial factors were administered to 276 couples within two weeks after birth. Depressive symptoms in mothers and fathers were assessed using the Edinburgh Postnatal Depression Scale (EPDS). After calculating the correlation coefficient between mothers and fathers' EPDS scores, univariate and multivariate linear regression analyses were performed to identify significant correlates of postnatal depressive symptoms in mothers and fathers. Prevalence of maternal and paternal postnatal depressive symptoms was 15.9% (EPDS>12) and 5.4% (EPDS>10), respectively. There was a moderate positive correlation between mothers and fathers' EPDS scores (r=.30, p<.001). Multivariate analyses indicated that parental stress was the strongest predictor for maternal and paternal postnatal depressive symptoms. Pregnancy- and birth-related distress and partners' EPDS scores were also associated with depressive symptoms in both parents. Relationship satisfaction was only inversely related with fathers' EPDS scores, while mothers' EPDS scores were additionally associated with critical life events, history of childhood violence, and birth-related physiological complaints. Since information about participation rates (those who declined) is unavailable, we cannot rule out sampling bias. Further, some psychosocial factors were assessed using single items. Since co-occurrence of depressive symptoms in mothers and fathers is high, developing and evaluating postnatal depression interventions for couples may be beneficial. Interventions to reduce parenting stress may help prevent parental postnatal depression. Copyright © 2015 Elsevier B.V. All rights reserved.

Widespread neuronal degeneration in rats following oral administration of methylmercury during the postnatal developing phase: a model of fetal-type minamata disease.

PubMed

Sakamoto, M; Wakabayashi, K; Kakita, A; Hitoshi Takahashi; Adachi, T; Nakano, A

1998-02-16

The neurotoxicity of methylmercury (MeHg) treatment during the postnatal developing phase in rats was studied. Rats on postnatal day 1 were orally administered 5 mg/kg/day methylmercury chloride (MMC) for more than 30 consecutive days. Body weight loss began 26 days after MMC was administered, and severe paralysis of the hind-limbs and unsteadiness appeared subsequently. Histopathologically, the widespread neuronal degeneration was observed in the cerebral neocortex, neostriatum, red nucleus, brainstem, cerebellum and spinal dorsal root ganglia on day 32. The widespread distribution of the lesions was quite similar to that in fetal cases of MeHg intoxication in Minamata, Japan. These findings suggest that MMC treatment during the postnatal development phase in rats produce a good model of fetal-type Minamata disease. Copyright 1998 Elsevier Science B.V.

Fetal and post-natal lung defects reveal a novel and required role for Fgf8 in lung development

PubMed Central

Yu, Shibin; Poe, Bryan; Schwarz, Margaret; Elliot, Sarah; Albertine, Kurt H.; Fenton, Stephen; Garg, Vidu; Moon, Anne M.

2016-01-01

The fibroblast growth factor, FGF8, has been shown to be essential for vertebrate cardiovascular, craniofacial, brain and limb development. Here we report that Fgf8 function is required for normal progression through the late fetal stages of lung development that culminate in alveolar formation. Budding, lobation and branching morphogenesis are unaffected in early stage Fgf8 hypomorphic and conditional mutant lungs. Excess proliferation during fetal development disrupts distal airspace formation, mesenchymal and vascular remodeling, and Type I epithelial cell differentiation resulting in postnatal respiratory failure and death. Our findings reveal a previously unknown, critical role for Fgf8 function in fetal lung development and suggest that this factor may also contribute to postnatal alveologenesis. Given the high number of premature infants with alveolar dysgenesis and lung dysplasia, and the accumulating evidence that short-term benefits of available therapies may be outweighed by long term detrimental effects on postnatal alveologenesis, the therapeutic implications of identifying a factor or pathway that can be targeted to stimulate normal alveolar development are profound. PMID:20727874

Cognition and behavioural development in early childhood: the role of birth weight and postnatal growth.

PubMed

Huang, Cheng; Martorell, Reynaldo; Ren, Aiguo; Li, Zhiwen

2013-02-01

We evaluate the relative importance of birth weight and postnatal growth for cognition and behavioural development in 8389 Chinese children, 4-7 years of age. Method Weight was the only size measure available at birth. Weight, height, head circumference and intelligence quotient (IQ) were measured between 4 and 7 years of age. Z-scores of birth weight and postnatal conditional weight gain to 4-7 years, as well as height and head circumference at 4-7 years of age, were the exposure variables. Z-scores of weight at 4-7 years were regressed on birth weight Z-scores, and the residual was used as the measure of postnatal conditional weight gain. The outcomes were child's IQ, measured by the Chinese Wechsler Young Children Scale of Intelligence, as well as internalizing behavioural problems, externalizing behavioural problems and other behavioural problems, evaluated by the Child Behavior Checklist 4-18. Multivariate regressions were conducted to investigate the relationship of birth weight and postnatal growth variables with the outcomes, separately for preterm children and term children. Both birth weight and postnatal weight gain were associated with IQ among term children; 1 unit increment in Z-score of birth weight (∼450 g) was associated with an increase of 1.60 [Confidence interval (CI): 1.18-2.02; P < 0.001] points in IQ, and 1 unit increment in conditional postnatal weight was associated with an increase of 0.46 (CI: 0.06-0.86; P = 0.02) points in IQ, after adjustment for confounders; similar patterns were observed when Z-scores of postnatal height and head circumference at age 4-7 years were used as alternative measurements of postnatal growth. Effect sizes of relationships with IQ were smaller than 0.1 of a standard deviation in all cases. Neither birth weight nor postnatal growth indicators were associated with behavioural outcomes among term children. In preterm children, neither birth weight nor postnatal growth measures were associated with IQ or behavioural outcomes. Both birth weight and postnatal growth were associated with IQ but not behavioural outcomes for Chinese term children aged 4-7 years, but the effect sizes were small. No relation between either birth weight or postnatal growth and cognition or behavioural outcomes was observed among preterm children aged 4-7 years.

An essential role for IGF2 in cartilage development and glucose metabolism during postnatal long bone growth.

PubMed

Uchimura, Tomoya; Hollander, Judith M; Nakamura, Daisy S; Liu, Zhiyi; Rosen, Clifford J; Georgakoudi, Irene; Zeng, Li

2017-10-01

Postnatal bone growth involves a dramatic increase in length and girth. Intriguingly, this period of growth is independent of growth hormone and the underlying mechanism is poorly understood. Recently, an IGF2 mutation was identified in humans with early postnatal growth restriction. Here, we show that IGF2 is essential for longitudinal and appositional murine postnatal bone development, which involves proper timing of chondrocyte maturation and perichondrial cell differentiation and survival. Importantly, the Igf2 null mouse model does not represent a simple delay of growth but instead uncoordinated growth plate development. Furthermore, biochemical and two-photon imaging analyses identified elevated and imbalanced glucose metabolism in the Igf2 null mouse. Attenuation of glycolysis rescued the mutant phenotype of premature cartilage maturation, thereby indicating that IGF2 controls bone growth by regulating glucose metabolism in chondrocytes. This work links glucose metabolism with cartilage development and provides insight into the fundamental understanding of human growth abnormalities. © 2017. Published by The Company of Biologists Ltd.

Maternal Postnatal Depression and the Development of Depression in Offspring up to 16 Years of Age

ERIC Educational Resources Information Center

Murray, Lynne; Arteche, Adriane; Fearon, Pasco; Halligan, Sarah; Goodyer, Ian; Cooper, Peter

2011-01-01

Objective: The aim of this study was to determine the developmental risk pathway to depression by 16 years in offspring of postnatally depressed mothers. Method: This was a prospective longitudinal study of offspring of postnatally depressed and nondepressed mothers; child and family assessments were made from infancy to 16 years. A total of 702…

Maternal postnatal mental health and later emotional-behavioural development of children: the mediating role of parenting behaviour.

PubMed

Giallo, R; Cooklin, A; Wade, C; D'Esposito, F; Nicholson, J M

2014-05-01

Maternal postnatal mental health difficulties have been associated with poor outcomes for children. One mechanism by which parent mental health can impact on children's outcomes is via its effects on parenting behaviour. The longitudinal relationships between maternal postnatal distress, parenting warmth, hostility and child well-being at age seven were examined for 2200 families participating in a population-based longitudinal study of Australian children. The relationship between postnatal distress and children's later emotional-behavioural development was mediated by parenting hostility, but not parenting warmth, even after accounting for concurrent maternal mental health. Postnatal distress was more strongly associated with lower parenting warmth for mothers without a past history of depression compared with mothers with a past history of depression. These findings underscore the contribution of early maternal well-being to later parenting and child outcomes, highlighting the importance of mental health and parenting support in the early parenting years. Implications for policy and practice are discussed. © 2013 John Wiley & Sons Ltd.

Long bone histology of the subterranean rodent Bathyergus suillus (Bathyergidae): ontogenetic pattern of cortical bone thickening.

PubMed

Montoya-Sanhueza, Germán; Chinsamy, Anusuya

2017-02-01

Patterns of bone development in mammals are best known from terrestrial and cursorial groups, but there is a considerable gap in our understanding of how specializations for life underground affect bone growth and development. Likewise, studies of bone microstructure in wild populations are still scarce, and they often include few individuals and tend to be focused on adults. For these reasons, the processes generating bone microstructural variation at intra- and interspecific levels are not fully understood. This study comprehensively examines the bone microstructure of an extant population of Cape dune molerats, Bathyergus suillus (Bathyergidae), the largest subterranean mammal endemic to the Western Cape of South Africa. The aim of this study is to investigate the postnatal bone growth of B. suillus using undecalcified histological sections (n = 197) of the femur, humerus, tibia-fibula, ulna and radius, including males and females belonging to different ontogenetic and reproductive stages (n = 42). Qualitative histological features demonstrate a wide histodiversity with thickening of the cortex mainly resulting from endosteal and periosteal bone depositions, whilst there is scarce endosteal resorption and remodeling throughout ontogeny. This imbalanced bone modeling allows the tissues deposited during ontogeny to remain relatively intact, thus preserving an excellent record of growth. The distribution of the different bone tissues observed in the cortex depends on ontogenetic status, anatomical features (e.g. muscle attachment structures) and location on the bone (e.g. anterior or lateral). The type of bone microstructure and modeling is discussed in relation to digging behavior, reproduction and physiology of this species. This study is the first histological assessment describing the process of cortical thickening in long bones of a fossorial mammal. © 2016 Anatomical Society.

Neocortical dendritic complexity is controlled during development by NOMA-GAP-dependent inhibition of Cdc42 and activation of cofilin.

PubMed

Rosário, Marta; Schuster, Steffen; Jüttner, René; Parthasarathy, Srinivas; Tarabykin, Victor; Birchmeier, Walter

2012-08-01

Neocortical neurons have highly branched dendritic trees that are essential for their function. Indeed, defects in dendritic arborization are associated with human neurodevelopmental disorders. The molecular mechanisms regulating dendritic arbor complexity, however, are still poorly understood. Here, we uncover the molecular basis for the regulation of dendritic branching during cortical development. We show that during development, dendritic branching requires post-mitotic suppression of the RhoGTPase Cdc42. By generating genetically modified mice, we demonstrate that this is catalyzed in vivo by the novel Cdc42-GAP NOMA-GAP. Loss of NOMA-GAP leads to decreased neocortical volume, associated specifically with profound oversimplification of cortical dendritic arborization and hyperactivation of Cdc42. Remarkably, dendritic complexity and cortical thickness can be partially restored by genetic reduction of post-mitotic Cdc42 levels. Furthermore, we identify the actin regulator cofilin as a key regulator of dendritic complexity in vivo. Cofilin activation during late cortical development depends on NOMA-GAP expression and subsequent inhibition of Cdc42. Strikingly, in utero expression of active cofilin is sufficient to restore postnatal dendritic complexity in NOMA-GAP-deficient animals. Our findings define a novel cell-intrinsic mechanism to regulate dendritic branching and thus neuronal complexity in the cerebral cortex.

Developmental emergence of fear/threat learning: neurobiology, associations and timing

PubMed Central

Tallot, L.; Doyère, V.; Sullivan, R. M.

2016-01-01

Pavlovian fear or threat conditioning, where a neutral stimulus takes on aversive properties through pairing with an aversive stimulus, has been an important tool for exploring the neurobiology of learning. In the past decades, this neurobehavioral approach has been expanded to include the developing infant. Indeed, protracted postnatal brain development permits the exploration of how incorporating the amygdala, prefrontal cortex and hippocampus into this learning system impacts the acquisition and expression of aversive conditioning. Here, we review the developmental trajectory of these key brain areas involved in aversive conditioning and relate it to pups’ transition to independence through weaning. Overall, the data suggests that adult-like features of threat learning emerge as the relevant brain areas become incorporated into this learning. Specifically, the developmental emergence of the amygdala permits cue learning and the emergence of the hippocampus permits context learning. We also describe unique features of learning in early life that block threat learning and enhance interaction with the mother or exploration of the environment. Finally, we describe the development of a sense of time within this learning and its involvement in creating associations. Together these data suggest that the development of threat learning is a useful tool for dissecting adult-like functioning of brain circuits, as well as providing unique insights into ecologically relevant developmental changes. PMID:26534899

A systematic approach towards the development of quality indicators for postnatal care after discharge in Flanders, Belgium.

PubMed

Helsloot, Kaat; Walraevens, Mieke; Besauw, Saskia Van; Van Parys, An-Sofie; Devos, Hanne; Holsbeeck, Ann Van; Roelens, Kristien

2017-05-01

to develop a set of quality indicators for postnatal care after discharge from the hospital, using a systematic approach. key elements of qualitative postnatal care were defined by performing a systematic review and the literature was searched for potential indicators (step 1). The potential indicators were evaluated by five criteria (validity, reliability, sensitivity, feasibility and acceptability) and by making use of the 'Appraisal of Guidelines for Research and Evaluation', the AIRE-instrument (step 2). In a modified Delphi-survey, the quality indicators were presented to a panel of experts in the field of postnatal care using an online tool (step 3). The final results led to a Flemish model of postnatal care (step 4). Flanders, Belgium PARTICIPANTS: health care professionals, representatives of health care organisations and policy makers with expertise in the field of postnatal care. after analysis 57 research articles, 10 reviews, one book and eight other documents resulted in 150 potential quality indicators in seven critical care domains. Quality assessment of the indicators resulted in 58 concept quality indicators which were presented to an expert-panel of health care professionals. After two Delphi-rounds, 30 quality indicators (six structure, 17 process, and seven outcome indicators) were found appropriate to monitor and improve the quality of postnatal care after discharge from the hospital. KEY CONCLUSIONS AND IMPLICATIONS FOR CLINICAL PRACTICE: the quality indicators resulted in a Flemish model of qualitative postnatal care that was implemented by health authorities as a minimum standard in the context of shortened length of stay. Postnatal care should be adjusted to a flexible length of stay and start in pregnancy with an individualised care plan that follows mother and new-born throughout pregnancy, childbirth and postnatal period. Criteria for discharge and local protocols about the organisation and content of care are essential to facilitate continuity of care. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effect of acute progestational hypoxia on the content of biogenic amines in the brain of albino rat pups: Peptide correction.

PubMed

Maslova, M V; Graf, A V; Sokolova, N A; Goncharenko, E N; Shestakova, S V; Kudryashova, N Yu; Andreeva, L A

2003-08-01

We studied the effect of exposure to acute hypobaric hypoxia in the progestational period on the content of biogenic amines in the brainstem and cerebral cortex in rat pups of different age. The possibility of correcting hypoxia-induced changes with regulatory peptides was evaluated. We found that early antenatal hypoxia disturbs maturation of catecholaminergic systems in the brain. It should be emphasized that the differences from the control varied depending on the age of rat pups. Single intranasal administration of Semax heptapeptides and beta-casomorphine-7 to pregnant females prevented changes in the content of biogenic amines in CNS of the offspring during postnatal ontogeny.

Eye-rotation-induced spatial reorganization of horizontal connections in field 17 of the cat cortex.

PubMed

Shkorbatova, P Yu; Alekseenko, S V

2006-06-01

Six cats with rotation of one or both eyes (strabismus) produced surgically in the early postnatal period demonstrated torsional deviation of the eyes by 10-20 degrees in addition to the rotation. The spatial distribution of retrograde labeled neurons in field 17 was studied by microiontophoretic administration of horseradish peroxidase into individual cortical columns in fields 17 and 18. These studies showed that rotation of the eyes increased the extent of horizontal neuronal connections in field 17 along the projection of the vertical meridian of the field of vision. It is suggested that this reorganization of neuronal connections may support functional changes compensating for eye rotation, as described in the literature.

Populations of subplate and interstitial neurons in fetal and adult human telencephalon.

PubMed

Judaš, Miloš; Sedmak, Goran; Pletikos, Mihovil; Jovanov-Milošević, Nataša

2010-10-01

In the adult human telencephalon, subcortical (gyral) white matter contains a special population of interstitial neurons considered to be surviving descendants of fetal subplate neurons [Kostovic & Rakic (1980) Cytology and the time of origin of interstitial neurons in the white matter in infant and adult human and monkey telencephalon. J Neurocytol9, 219]. We designate this population of cells as superficial (gyral) interstitial neurons and describe their morphology and distribution in the postnatal and adult human cerebrum. Human fetal subplate neurons cannot be regarded as interstitial, because the subplate zone is an essential part of the fetal cortex, the major site of synaptogenesis and the 'waiting' compartment for growing cortical afferents, and contains both projection neurons and interneurons with distinct input-output connectivity. However, although the subplate zone is a transient fetal structure, many subplate neurons survive postnatally as superficial (gyral) interstitial neurons. The fetal white matter is represented by the intermediate zone and well-defined deep periventricular tracts of growing axons, such as the corpus callosum, anterior commissure, internal and external capsule, and the fountainhead of the corona radiata. These tracts gradually occupy the territory of transient fetal subventricular and ventricular zones.The human fetal white matter also contains distinct populations of deep fetal interstitial neurons, which, by virtue of their location, morphology, molecular phenotypes and advanced level of dendritic maturation, remain distinct from subplate neurons and neurons in adjacent structures (e.g. basal ganglia, basal forebrain). We describe the morphological, histochemical (nicotinamide-adenine dinucleotide phosphate-diaphorase) and immunocytochemical (neuron-specific nuclear protein, microtubule-associated protein-2, calbindin, calretinin, neuropeptide Y) features of both deep fetal interstitial neurons and deep (periventricular) interstitial neurons in the postnatal and adult deep cerebral white matter (i.e. corpus callosum, anterior commissure, internal and external capsule and the corona radiata/centrum semiovale). Although these deep interstitial neurons are poorly developed or absent in the brains of rodents, they represent a prominent feature of the significantly enlarged white matter of human and non-human primate brains. © 2010 The Authors. Journal of Anatomy © 2010 Anatomical Society of Great Britain and Ireland.

A novel lens epithelium gene, LEP503, is highly conserved in different vertebrate species and is developmentally regulated in postnatal rat lens.

PubMed

Wen, Y; Sachs, G; Athmann, C

2000-02-01

The development of the lens is dependent on the proliferation of lens epithelial cells and their differentiation into fiber cells near the lens bow/equator. Identification of genes specifically expressed in the lens epithelial cells and their functions may provide insight into molecular events that regulate the processes of lens epithelial cell differentiation. In this study, a novel lens epithelium gene product, LEP503, identified from rat by a subtractive cDNA cloning strategy was investigated in the genome organization, mRNA expression and protein localization. The genomic sequences for LEP503 isolated from rat, mouse and human span 1754 bp, 1694 bp and 1895 bp regions encompassing the 5'-flanking region, two exons, one intron and 3'-flanking region. All exon-intron junction sequences conform to the GT/AG rule. Both mouse and human LEP503 genes show very high identity (93% for mouse and 79% for human) to rat LEP503 gene in the exon 1 that contains an open reading frame coding for a protein of 61 amino acid residues with a leucine-rich domain. The deduced protein sequences also show high identity (91% between mouse and rat and 77% between human and rat). Western blot shows that LEP503 is present as a specific approximately 6.9 kDa band in the water-insoluble-urea-soluble fraction of lens cortex where lens epithelium is included. Immuno-staining shows that LEP503 is localized in the epithelial cells along the entire anterior surface of rat lens. Developmentally, LEP503 is expressed at a low level at newborn, and then the expression level increases by about ten-fold around postnatal day 14 and remains at this high level for about 25 days before it drops back to the low level by postnatal day 84. These data suggest that the LEP503 may be an important lens epithelial cell gene involving the processes of epithelial cell differentiation. Copyright 2000 Academic Press.

The Postnatal Development of Spinal Sensory Processing

NASA Astrophysics Data System (ADS)

Fitzgerald, Maria; Jennings, Ernest

1999-07-01

The mechanisms by which infants and children process pain should be viewed within the context of a developing sensory nervous system. The study of the neurophysiological properties and connectivity of sensory neurons in the developing spinal cord dorsal horn of the intact postnatal rat has shed light on the way in which the newborn central nervous system analyzes cutaneous innocuous and noxious stimuli. The receptive field properties and evoked activity of newborn dorsal horn cells to single repetitive and persistent innocuous and noxious inputs are developmentally regulated and reflect the maturation of excitatory transmission within the spinal cord. These changes will have an important influence on pain processing in the postnatal period.

[Effects of nano-lead exposure on learning and memory as well as iron homeostasis in brain of offspring rats].

PubMed

Gao, Jing; Su, Hong; Yin, Jingwen; Cao, Fuyuan; Feng, Peipei; Liu, Nan; Xue, Ling; Zheng, Guoying; Li, Qingzhao; Zhang, Yanshu

2015-06-01

To investigate the effects of nano-lead exposure on learning and memory and iron homeostasis in the brain of the offspring rats on postnatal day 21 (PND21) and postnatal day 42 (PND42). Twenty adult pregnant female Sprague-Dawley rats were randomly divided into control group and nano-lead group. Rats in the nano-lead group were orally administrated 10 mg/kg nano-lead, while rats in the control group were administrated an equal volume of normal saline until PND21. On PND21, the offspring rats were weaned and given the same treatment as the pregnant rats until 42 days after birth. The learning and memory ability of offspring rats on PND21 and PND42 was evaluated by Morris water maze test. The hippocampus and cortex s amples of offspring rats on PND21 and PND42 were collected to determine iron and lead levels in the hippocampus and cortex by inductively coupled plasma-mass spectrometry. The distributions of iron in the hippocampus and cortex were observed by Perl's iron staining. The expression levels of ferritin, ferroportin 1 (FPN1), hephaestin (HP), and ceruloplasmin (CP) were measured by enzyme-linked immunosorbent assay. After nano-lead exposure, the iron content in the cortex of offspring rats on PND21 and PND42 in the nano-lead group was significantly higher than those in the control group (32.63 ± 6.03 µg/g vs 27.04 ± 5.82 µg/g, P<0.05; 46.20 ±10.60 µg/g vs 36.61 ± 10.2µg/g, P<0.05). The iron content in the hippocampus of offspring rats on PND42 in the nano-lead group was significantly higher than that in the control group (56.9 ± 4.37µg/g vs 37.71 ± 6.92µg/g, P<0.05). The Perl's staining showed massive iron deposition in the cortex and hippocampus in the nano-lead group. FPNl level in the cotfex of offspring rats on PND21 in the nano-lead group was significantly lower than that in the control group (3.64 ± 0.23 ng/g vs 4.99 ± 0.95 ng/g, P<0.05). FPN1 level in the hippocampus of offspring rats on PND42 in the nano-lead group was significantly lower than that in the control group (2.28 ± 0.51 ng/g vs 3.69 ± 0.69 ng/g, P<0.05). The escape latencies of offspring rats on PND21 and PND42 in the nano-lead group were longer than those in the control group (15.54 ± 2.89 s vs 9.01 ± 4.66 s; 6.16 ± 1.42 s vs 4.26 ± 1.51 s). The numbers of platform crossings of offspring rats on PND21 and PND42 in the nano- lead group were significantly lower than those in the control group (7.77 ± 2.16 times vs 11.2 ± 1.61 times, P<0.05; 8.12 ± 1.51 times vs 13.0 ± 2.21 times, P<0.05). n Nano-lead exposure can result in iron homeostasis disorders in the hippocampus and cortex of offspring rats and affect their learning and memory ability.

Mosaic analysis of gene function in postnatal mouse brain development by using virus-based Cre recombination.

PubMed

Gibson, Daniel A; Ma, Le

2011-08-01

Normal brain function relies not only on embryonic development when major neuronal pathways are established, but also on postnatal development when neural circuits are matured and refined. Misregulation at this stage may lead to neurological and psychiatric disorders such as autism and schizophrenia. Many genes have been studied in the prenatal brain and found crucial to many developmental processes. However, their function in the postnatal brain is largely unknown, partly because their deletion in mice often leads to lethality during neonatal development, and partly because their requirement in early development hampers the postnatal analysis. To overcome these obstacles, floxed alleles of these genes are currently being generated in mice. When combined with transgenic alleles that express Cre recombinase in specific cell types, conditional deletion can be achieved to study gene function in the postnatal brain. However, this method requires additional alleles and extra time (3-6 months) to generate the mice with appropriate genotypes, thereby limiting the expansion of the genetic analysis to a large scale in the mouse brain. Here we demonstrate a complementary approach that uses virally-expressed Cre to study these floxed alleles rapidly and systematically in postnatal brain development. By injecting recombinant adeno-associated viruses (rAAVs) encoding Cre into the neonatal brain, we are able to delete the gene of interest in different regions of the brain. By controlling the viral titer and coexpressing a fluorescent protein marker, we can simultaneously achieve mosaic gene inactivation and sparse neuronal labeling. This method bypasses the requirement of many genes in early development, and allows us to study their cell autonomous function in many critical processes in postnatal brain development, including axonal and dendritic growth, branching, and tiling, as well as synapse formation and refinement. This method has been used successfully in our own lab (unpublished results) and others, and can be extended to other viruses, such as lentivirus, as well as to the expression of shRNA or dominant active proteins. Furthermore, by combining this technique with electrophysiology as well as recently-developed optical imaging tools, this method provides a new strategy to study how genetic pathways influence neural circuit development and function in mice and rats.

Differential microRNA expression in the prefrontal cortex of mouse offspring induced by glyphosate exposure during pregnancy and lactation.

PubMed

Ji, Hua; Xu, Linhao; Wang, Zheng; Fan, Xinli; Wu, Lihui

2018-03-01

Glyphosate is the active ingredient in numerous herbicide formulations. The role of glyphosate in neurotoxicity has been reported in human and animal models. However, the detailed mechanism of the role of glyphosate in neuronal development remains unknown. Recently, several studies have reported evidence linking neurodevelopmental disorders (NDDs) with gestational glyphosate exposure. The current group previously identified microRNAs (miRNAs) that are associated with the etiology of NDDs, but their expression levels in the developing brain following glyphosate exposure have not been characterized. In the present study, miRNA expression patterns were evaluated in the prefrontal cortex (PFC) of 28 postnatal day mouse offspring following glyphosate exposure during pregnancy and lactation. An miRNA microarray detected 55 upregulated and 19 downregulated miRNAs in the PFC of mouse offspring, and 20 selected deregulated miRNAs were further evaluated by quantitative polymerase chain reaction (PCR). A total of 11 targets of these selected deregulated miRNAs were analyzed using bioinformatics. Gene Ontology (GO) terms associated with the relevant miRNAs included neurogenesis (GO:0050769), neuron differentiation (GO:0030182) and brain development (GO:0007420). The genes Cdkn1a, Numbl, Notch1, Fosl1 and Lef1 are involved in the Wnt and Notch signaling pathways, which are closely associated with neural development. PCR arrays for the mouse Wnt and Notch signaling pathways were used to validate the effects of glyphosate on the expression pattern of genes involved in the Wnt and Notch pathways. Nr4a2 and Wnt7b were downregulated, while Dkk1, Dixdc1, Runx1, Shh, Lef-1 and Axin2 were upregulated in the PFC of mice offspring following glyphosate exposure during pregnancy and lactation. These results indicated abnormalities of the Wnt/β-catenin and Notch pathways. These findings may be of particular interest for understanding the mechanism of glyphosate-induced neurotoxicity, as well as helping to clarify the association between glyphosate and NDDs.

Differential microRNA expression in the prefrontal cortex of mouse offspring induced by glyphosate exposure during pregnancy and lactation

PubMed Central

Ji, Hua; Xu, Linhao; Wang, Zheng; Fan, Xinli; Wu, Lihui

2018-01-01

Glyphosate is the active ingredient in numerous herbicide formulations. The role of glyphosate in neurotoxicity has been reported in human and animal models. However, the detailed mechanism of the role of glyphosate in neuronal development remains unknown. Recently, several studies have reported evidence linking neurodevelopmental disorders (NDDs) with gestational glyphosate exposure. The current group previously identified microRNAs (miRNAs) that are associated with the etiology of NDDs, but their expression levels in the developing brain following glyphosate exposure have not been characterized. In the present study, miRNA expression patterns were evaluated in the prefrontal cortex (PFC) of 28 postnatal day mouse offspring following glyphosate exposure during pregnancy and lactation. An miRNA microarray detected 55 upregulated and 19 downregulated miRNAs in the PFC of mouse offspring, and 20 selected deregulated miRNAs were further evaluated by quantitative polymerase chain reaction (PCR). A total of 11 targets of these selected deregulated miRNAs were analyzed using bioinformatics. Gene Ontology (GO) terms associated with the relevant miRNAs included neurogenesis (GO:0050769), neuron differentiation (GO:0030182) and brain development (GO:0007420). The genes Cdkn1a, Numbl, Notch1, Fosl1 and Lef1 are involved in the Wnt and Notch signaling pathways, which are closely associated with neural development. PCR arrays for the mouse Wnt and Notch signaling pathways were used to validate the effects of glyphosate on the expression pattern of genes involved in the Wnt and Notch pathways. Nr4a2 and Wnt7b were downregulated, while Dkk1, Dixdc1, Runx1, Shh, Lef-1 and Axin2 were upregulated in the PFC of mice offspring following glyphosate exposure during pregnancy and lactation. These results indicated abnormalities of the Wnt/β-catenin and Notch pathways. These findings may be of particular interest for understanding the mechanism of glyphosate-induced neurotoxicity, as well as helping to clarify the association between glyphosate and NDDs. PMID:29467848

Changes in fine structure of pericytes and novel desmin-immunopositive perivascular cells during postnatal development in rat anterior pituitary gland.

PubMed

Jindatip, Depicha; Fujiwara, Ken; Horiguchi, Kotaro; Tsukada, Takehiro; Kouki, Tom; Yashiro, Takashi

2013-09-01

Pericytes are perivascular cells associated with capillaries. We previously demonstrated that pericytes, identified by desmin immunohistochemistry, produce type I and III collagens in the anterior pituitary gland of adult rats. In addition, we recently used desmin immunoelectron microscopy to characterize a novel type of perivascular cell, dubbed a desmin-immunopositive perivascular cell, in the anterior pituitary. These two types of perivascular cells differ in fine structure. The present study attempted to characterize the morphological features of pituitary pericytes and novel desmin-immunopositive perivascular cells during postnatal development, in particular their role in collagen synthesis. Desmin immunostaining revealed numerous perivascular cells at postnatal day 5 (P5) and P10. Transmission electron microscopy showed differences in the fine structure of the two cell types, starting at P5. Pericytes had well-developed rough endoplasmic reticulum and Golgi apparatus at P5 and P10. The novel desmin-immunopositive perivascular cells exhibited dilated cisternae of rough endoplasmic reticulum at P5-P30. In addition, during early postnatal development in the gland, a number of type I and III collagen-expressing cells were observed, as were high expression levels of these collagen mRNAs. We conclude that pituitary pericytes and novel desmin-immunopositive perivascular cells contain well-developed cell organelles and that they actively synthesize collagens during the early postnatal period.

Disproportionate cardiac hypertrophy during early postnatal development in infants born preterm.

PubMed

Aye, Christina Y L; Lewandowski, Adam J; Lamata, Pablo; Upton, Ross; Davis, Esther; Ohuma, Eric O; Kenworthy, Yvonne; Boardman, Henry; Wopperer, Samuel; Packham, Alice; Adwani, Satish; McCormick, Kenny; Papageorghiou, Aris T; Leeson, Paul

2017-07-01

BackgroundAdults born very preterm have increased cardiac mass and reduced function. We investigated whether a hypertrophic phenomenon occurs in later preterm infants and when this occurs during early development.MethodsCardiac ultrasound was performed on 392 infants (33% preterm at mean gestation 34±2 weeks). Scans were performed during fetal development in 137, at birth and 3 months of postnatal age in 200, and during both fetal and postnatal development in 55. Cardiac morphology and function was quantified and computational models created to identify geometric changes.ResultsAt birth, preterm offspring had reduced cardiac mass and volume relative to body size with a more globular heart. By 3 months, ventricular shape had normalized but both left and right ventricular mass relative to body size were significantly higher than expected for postmenstrual age (left 57.8±41.9 vs. 27.3±29.4%, P<0.001; right 39.3±38.1 vs. 16.6±40.8, P=0.002). Greater changes were associated with lower gestational age at birth (left P<0.001; right P=0.001).ConclusionPreterm offspring, including those born in late gestation, have a disproportionate increase in ventricular mass from birth up to 3 months of postnatal age. These differences were not present before birth. Early postnatal development may provide a window for interventions relevant to long-term cardiovascular health.

Disproportionate cardiac hypertrophy during early postnatal development in infants born preterm

PubMed Central

Aye, Christina Y L; Lewandowski, Adam J; Lamata, Pablo; Upton, Ross; Davis, Esther; Ohuma, Eric O; Kenworthy, Yvonne; Boardman, Henry; Wopperer, Samuel; Packham, Alice; Adwani, Satish; McCormick, Kenny; Papageorghiou, Aris T; Leeson, Paul

2017-01-01

Background Adults born very preterm have increased cardiac mass and reduced function. We investigated whether a hypertrophic phenomenon occurs in later preterm infants and when this occurs during early development. Methods Cardiac ultrasound was performed on 392 infants (33% preterm at mean gestation 34±2 weeks). Scans were performed during fetal development in 137, at birth and 3 months of postnatal age in 200, and during both fetal and postnatal development in 55. Cardiac morphology and function was quantified and computational models created to identify geometric changes. Results At birth, preterm offspring had reduced cardiac mass and volume relative to body size with a more globular heart. By 3 months, ventricular shape had normalized but both left and right ventricular mass relative to body size were significantly higher than expected for postmenstrual age (left 57.8±41.9 vs. 27.3±29.4%, P<0.001; right 39.3±38.1 vs. 16.6±40.8, P=0.002). Greater changes were associated with lower gestational age at birth (left P<0.001; right P=0.001). Conclusion Preterm offspring, including those born in late gestation, have a disproportionate increase in ventricular mass from birth up to 3 months of postnatal age. These differences were not present before birth. Early postnatal development may provide a window for interventions relevant to long-term cardiovascular health. PMID:28399117

Postnatal proteasome inhibition induces neurodegeneration and cognitive deficiencies in adult mice: a new model of neurodevelopment syndrome.

PubMed

Romero-Granados, Rocío; Fontán-Lozano, Ángela; Aguilar-Montilla, Francisco Javier; Carrión, Ángel Manuel

2011-01-01

Defects in the ubiquitin-proteasome system have been related to aging and the development of neurodegenerative disease, although the effects of deficient proteasome activity during early postnatal development are poorly understood. Accordingly, we have assessed how proteasome dysfunction during early postnatal development, induced by administering proteasome inhibitors daily during the first 10 days of life, affects the behaviour of adult mice. We found that this regime of exposure to the proteasome inhibitors MG132 or lactacystin did not produce significant behavioural or morphological changes in the first 15 days of life. However, towards the end of the treatment with proteasome inhibitors, there was a loss of mitochondrial markers and activity, and an increase in DNA oxidation. On reaching adulthood, the memory of mice that were injected with proteasome inhibitors postnatally was impaired in hippocampal and amygdala-dependent tasks, and they suffered motor dysfunction and imbalance. These behavioural deficiencies were correlated with neuronal loss in the hippocampus, amygdala and brainstem, and with diminished adult neurogenesis. Accordingly, impairing proteasome activity at early postnatal ages appears to cause morphological and behavioural alterations in adult mice that resemble those associated with certain neurodegenerative diseases and/or syndromes of mental retardation.

Post-natal myogenic and adipogenic developmental

PubMed Central

Konings, Gonda; van Weeghel, Michel; van den Hoogenhof, Maarten MG; Gijbels, Marion; van Erk, Arie; Schoonderwoerd, Kees; van den Bosch, Bianca; Dahlmans, Vivian; Calis, Chantal; Houten, Sander M; Misteli, Tom

2011-01-01

A-type lamins are a major component of the nuclear lamina. Mutations in the LMNA gene, which encodes the A-type lamins A and C, cause a set of phenotypically diverse diseases collectively called laminopathies. While adult LMNA null mice show various symptoms typically associated with laminopathies, the effect of loss of lamin A/C on early post-natal development is poorly understood. Here we developed a novel LMNA null mouse (LMNAGT−/−) based on genetrap technology and analyzed its early post-natal development. We detect LMNA transcripts in heart, the outflow tract, dorsal aorta, liver and somites during early embryonic development. Loss of A-type lamins results in severe growth retardation and developmental defects of the heart, including impaired myocyte hypertrophy, skeletal muscle hypotrophy, decreased amounts of subcutaneous adipose tissue and impaired ex vivo adipogenic differentiation. These defects cause death at 2 to 3 weeks post partum associated with muscle weakness and metabolic complications, but without the occurrence of dilated cardiomyopathy or an obvious progeroid phenotype. Our results indicate that defective early post-natal development critically contributes to the disease phenotypes in adult laminopathies. PMID:21818413

Homeodomain interacting protein kinase 2 regulates postnatal development of enteric dopaminergic neurons and glia via BMP signaling.

PubMed

Chalazonitis, Alcmène; Tang, Amy A; Shang, Yulei; Pham, Tuan D; Hsieh, Ivy; Setlik, Wanda; Gershon, Michael D; Huang, Eric J

2011-09-28

Trophic factor signaling is important for the migration, differentiation, and survival of enteric neurons during development. The mechanisms that regulate the maturation of enteric neurons in postnatal life, however, are poorly understood. Here, we show that transcriptional cofactor HIPK2 (homeodomain interacting protein kinase 2) is required for the maturation of enteric neurons and for regulating gliogenesis during postnatal development. Mice lacking HIPK2 display a spectrum of gastrointestinal (GI) phenotypes, including distention of colon and slowed GI transit time. Although loss of HIPK2 does not affect the enteric neurons in prenatal development, a progressive loss of enteric neurons occurs during postnatal life in Hipk2(-/-) mutant mice that preferentially affects the dopaminergic population of neurons in the caudal region of the intestine. The mechanism by which HIPK2 regulates postnatal enteric neuron development appears to involve the response of enteric neurons to bone morphogenetic proteins (BMPs). Specifically, compared to wild type mice, a larger proportion of enteric neurons in Hipk2(-/-) mutants have an abnormally high level of phosphorylated Smad1/5/8. Consistent with the ability of BMP signaling to promote gliogenesis, Hipk2(-/-) mutants show a significant increase in glia in the enteric nervous system. In addition, numbers of autophagosomes are increased in enteric neurons in Hipk2(-/-) mutants, and synaptic maturation is arrested. These results reveal a new role for HIPK2 as an important transcriptional cofactor that regulates the BMP signaling pathway in the maintenance of enteric neurons and glia, and further suggest that HIPK2 and its associated signaling mechanisms may be therapeutically altered to promote postnatal neuronal maturation.

Educating the European Citizen in the Global Age: Engaging with the Post-National and Identifying a Research Agenda

ERIC Educational Resources Information Center

Marshall, Harriet

2009-01-01

In recent decades there have been increased calls for UK schools to develop a more European and global orientation in their pedagogy and curriculum, and to equip children and young people with post-national knowledge, skills, and dispositions. This paper examines some key problems in post-national conceptions of citizenship education, in order to…

Lipidomics reveals dramatic lipid compositional changes in the maturing postnatal lung

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dautel, Sydney E.; Kyle, Jennifer E.; Clair, Geremy

Lung immaturity is a major cause of morbidity and mortality in premature infants. Understanding the molecular mechanisms driving normal lung development could provide insights on how to ameliorate disrupted development. While transcriptomic and proteomic analyses of normal lung development have been previously reported, characterization of changes in the lipidome is lacking. Lipids play significant roles in the lung, such as dipalmitoylcholine in pulmonary surfactant; however, many of the roles of specific lipid species in normal lung development, as well as in disease states, are not well defined. In this study, we used liquid chromatography-mass spectrometry (LC-MS/MS) to investigate the murinemore » lipidome during normal postnatal lung development. Lipidomics analysis of lungs from post-natal day 7, day 14 and 6-8 week mice (adult) identified 928 unique lipids across 21 lipid subclasses, with dramatic alterations in the lipidome across developmental stages. Our data confirmed previously recognized aspects of post-natal lung development and revealed several insights, including in sphingolipid-mediated apoptosis, inflammation and energy storage/usage. Complementary proteomics, metabolomics and chemical imaging corroborated these observations. Finally, this multi-omic view provides a unique resource and deeper insight into normal pulmonary development.« less

Lipidomics reveals dramatic lipid compositional changes in the maturing postnatal lung

DOE PAGES

Dautel, Sydney E.; Kyle, Jennifer E.; Clair, Geremy; ...

2017-02-01

Lung immaturity is a major cause of morbidity and mortality in premature infants. Understanding the molecular mechanisms driving normal lung development could provide insights on how to ameliorate disrupted development. While transcriptomic and proteomic analyses of normal lung development have been previously reported, characterization of changes in the lipidome is lacking. Lipids play significant roles in the lung, such as dipalmitoylcholine in pulmonary surfactant; however, many of the roles of specific lipid species in normal lung development, as well as in disease states, are not well defined. In this study, we used liquid chromatography-mass spectrometry (LC-MS/MS) to investigate the murinemore » lipidome during normal postnatal lung development. Lipidomics analysis of lungs from post-natal day 7, day 14 and 6-8 week mice (adult) identified 928 unique lipids across 21 lipid subclasses, with dramatic alterations in the lipidome across developmental stages. Our data confirmed previously recognized aspects of post-natal lung development and revealed several insights, including in sphingolipid-mediated apoptosis, inflammation and energy storage/usage. Complementary proteomics, metabolomics and chemical imaging corroborated these observations. Finally, this multi-omic view provides a unique resource and deeper insight into normal pulmonary development.« less

Neonatal olfactory bulbectomy enhances locomotor activity, exploratory behavior and binding of NMDA receptors in pre-pubertal rats.

PubMed

Flores, G; Ibañez-Sandoval, O; Silva-Gómez, A B; Camacho-Abrego, I; Rodríguez-Moreno, A; Morales-Medina, J C

2014-02-14

In this study, we investigated the effect of neonatal olfactory bulbectomy (nOBX) on behavioral paradigms related to olfaction such as exploratory behavior, locomotor activity in a novel environment and social interaction. We also studied the effect of nOBX on the activity of the N-methyl-d-aspartate (NMDA) subtype of glutamate receptors during development. The behavioral effects of nOBX (postnatal day 7, PD7) were investigated in pre- (PD30) and post-pubertal (PD60) Wistar rats. NMDA receptor activity was measured with [(125)I]MK-801 in the brain regions associated with the olfactory circuitry. A significant increase in the novelty-induced locomotion was seen in the pre-pubertal nOBX rats. Although the locomotor effect was less marked than in pre-pubertal rats, the nOBX rats tested post-pubertally failed to habituate to the novel situation as quickly as the sham- and normal- controls. Pre-pubertally, the head-dipping behavior was enhanced in nOBX rats compared with sham-operated and normal controls, while normal exploratory behavior was observed between groups in adulthood. In contrast, social interaction was increased in post-pubertal animals that underwent nOBX. Both pre- and post-pubertal nOBX rats recovered olfaction. Interestingly, pre-pubertal rats showed a significant increase in the [(125)I]MK-801 binding in the piriform cortex, dorsal hippocampus, inner and outer layers of the frontal cortex and outer layer of the cingulate cortex. At post-pubertal age, no significant differences in [(125)I]MK-801 binding were observed between groups at any of the brain regions analyzed. These results suggest that nOBX produces pre-pubertal behavioral disturbances and NMDA receptor changes that are transitory with recovery of olfaction early in adulthood. Copyright © 2013 IBRO. Published by Elsevier Ltd. All rights reserved.

Neurochemical effects of a 20 kHz magnetic field on the central nervous system in prenatally exposed mice

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dimberg, Y.

1995-09-01

C57/B1 mice were exposed during pregnancy (gestation days 0--19) to a 20 kHz magnetic field (MF). The asymmetric sawtooth-waveform magnetic field in the exposed racks had a flux density of 15 {micro}T (peak to peak). After 19 days, the exposure was terminated, and the mice were housed individually under normal laboratory conditions. On postnatal day (PD) 1, PD21, and PD308, various neurochemical markers in the brains of the offspring were investigated and the brains weighed. No significant difference was found in the whole brain weight at PD1 or PD21 between exposed offspring and control animals. However, on PD308, a significantmore » decrease in weight of the whole brain was detected in exposed animals. No significant differences were found in the weight of cortex, hippocampus, septum, or cerebellum on nay of the sampling occasions, nor were any significant differences detected in protein-, DNA-level, nerve growth factor (NGF), acetylcholine esterase- (AChE), or 2{prime},3{prime}-cyclic nucleotide 3{prime}-phosphodiesterase- (CNP; marker for oligodendrocytes) activities on PD21 in cerebellum. Cortex showed a more complex pattern of response to MF: MF treatment resulted in a decrease in DNA level and increases in the activities of CNP, AChE, and NGF protein. On PD308, the amount of DNA was significantly reduced in MF-treated cerebellum and CNP activity was still enhanced in MF-treated cortex compared to controls. Most of the effect of MF treatment during the embryonic period were similar to those induced by ionizing radiation but much weaker. However, the duration of the exposure required to elucidate the response of different markers to MF seems to be greater and effects appear later during development compared to responses to ionizing radiation.« less

Life-time expression of the proteins peroxiredoxin, beta-synuclein, PARK7/DJ-1, and stathmin in the primary visual and primary somatosensory cortices in rats

PubMed Central

Böhm, Michael R. R.; Melkonyan, Harutyun; Thanos, Solon

2015-01-01

Four distinct proteins are regulated in the aging neuroretina and may be regulated in the cerebral cortex, too: peroxiredoxin, beta-synuclein, PARK[Parkinson disease(autosomal recessive, early onset)]7/DJ-1, and Stathmin. Thus, we performed a comparative analysis of these proteins in the the primary somatosensory cortex (S1) and primary visual cortex (V1) in rats, in order to detect putative common development-, maturation- and age-related changes. The expressions of peroxiredoxin, beta-synuclein, PARK[Parkinson disease (autosomal recessive, early onset)]7/DJ-1, and Stathmin were compared in the newborn, juvenile, adult, and aged S1 and V1. Western blot (WB), quantitative reverse-transcription polymerase chain reaction (qRT-PCR), and immunohistochemistry (IHC) analyses were employed to determine whether the changes identified by proteomics were verifiable at the cellular and molecular levels. All of the proteins were detected in both of the investigated cortical areas. Changes in the expressions of the four proteins were found throughout the life-time of the rats. Peroxiredoxin expression remained unchanged over life-time. Beta-Synuclein expression was massively increased up to the adult stage of life in both the S1 and V1. PARK[Parkinson disease (autosomal recessive, early onset)]7/DJ-1 exhibited a massive up-regulation in both the S1 and V1 at all ages. Stathmin expression was massively down regulated after the neonatal period in both the S1 and V1. The detected protein alterations were analogous to their retinal profiles. This study is the first to provide evidence that peroxiredoxin, beta-synuclein, PARK[Parkinson disease (autosomal recessive, early onset)]7/DJ-1, and Stathmin are associated with postnatal maturation and aging in both the S1 and V1 of rats. These changes may indicate their involvement in key functional pathways and may account for the onset or progression of age-related pathologies. PMID:25788877

Critical androgen-sensitive periods of rat penis and clitoris development.

PubMed

Welsh, Michelle; MacLeod, David J; Walker, Marion; Smith, Lee B; Sharpe, Richard M

2010-02-01

Androgen control of penis development/growth is unclear. In rats, androgen action in a foetal 'masculinisation programming window' (MPW; e15.5-e18.5)' predetermines penile length and hypospadias occurrence. This has implications for humans (e.g. micropenis). Our studies aimed to establish in rats when androgen action/administration affects development/growth of the penis and if deficits in MPW androgen action were rescuable postnatally. Thus, pregnant rats were treated with flutamide during the MPW +/- postnatal testosterone propionate (TP) treatment. To assess penile growth responsiveness, rats were treated with TP in various time windows (late foetal, neonatal through early puberty, puberty onset, or combinations thereof). Phallus length, weight, and morphology, hypospadias and anogenital distance (AGD) were measured in mid-puberty (d25) or adulthood (d90) in males and females, plus serum testosterone in adult males. MPW flutamide exposure reduced adult penile length and induced hypospadias dose-dependently; this was not rescued by postnatal TP treatment. In normal rats, foetal (e14.5-e21.5) TP exposure did not affect male penis size but increased female clitoral size. In males, TP exposure from postnatal d1-24 or at puberty (d15-24), increased penile length at d25, but not ultimately in adulthood. Foetal + postnatal TP (e14-postnatal d24) increased penile size at d25 but reduced it at d90 (due to reduced endogenous testosterone). In females, this treatment caused the biggest increase in adult clitoral size but, unlike in males, phallus size was unaffected by TP during puberty (d15-24). Postnatal TP treatment advanced penile histology at d25 to more resemble adult histology. AGD strongly correlated with final penis length. It is concluded that adult penile size depends critically on androgen action during the MPW but subsequent growth depends on later androgen exposure. Foetal and/or postnatal TP exposure does not increase adult penile size above its 'predetermined' length though its growth towards this maximum is advanced by peripubertal TP treatment.

Slower postnatal motor development in infants of mothers with latent toxoplasmosis during the first 18 months of life.

PubMed

Kaňková, Sárka; Sulc, Jan; Křivohlavá, Romana; Kuběna, Aleš; Flegr, Jaroslav

2012-11-01

Toxoplasmosis, a zoonosis caused by a protozoan, Toxoplasma gondii, is probably the most widespread human parasitosis in developed countries. Pregnant women with latent toxoplasmosis have seemingly younger fetuses especially in the 16th week of gestation, which suggests that fetuses of Toxoplasma-infected mothers have slower rates of development in the first trimester of pregnancy. In the present retrospective cohort study, we analyzed data on postnatal motor development of infants from 331 questionnaire respondents including 53 Toxoplasma-infected mothers to search for signs of early postnatal development disorders. During the first year of life, a slower postnatal motor development was observed in infants of mothers with latent toxoplasmosis. These infants significantly later developed the ability to control the head position (p=0.039), to roll from supine to prone position (p=0.022) and were slightly later to begin crawling (p=0.059). Our results are compatible with the hypothesis that the difference in the rates of prenatal and early postnatal development between children of Toxoplasma-negative and Toxoplasma-positive mothers might be caused by a decreased stringency of embryo quality control in partly immunosuppressed Toxoplasma-positive mothers resulting in a higher proportion of infants with genetic or developmental disorders in offspring. However, because of relatively low return rate of questionnaires and an associated risk of a sieve effect, our results should be considered as preliminary and performing a large scale prospective study in the future is critically needed. Copyright © 2012 Elsevier Ltd. All rights reserved.

Blockade of α2-adrenergic receptors in prelimbic cortex: impact on cocaine self-administration in adult spontaneously hypertensive rats following adolescent atomoxetine treatment.

PubMed

Baskin, Britahny M; Nic Dhonnchadha, Bríd Á; Dwoskin, Linda P; Kantak, Kathleen M

2017-10-01

Research with the spontaneously hypertensive rat (SHR) model of attention deficit/hyperactivity disorder demonstrated that chronic methylphenidate treatment during adolescence increased cocaine self-administration established during adulthood under a progressive ratio (PR) schedule. Compared to vehicle, chronic atomoxetine treatment during adolescence failed to increase cocaine self-administration under a PR schedule in adult SHR. We determined if enhanced noradrenergic transmission at α2-adrenergic receptors within prefrontal cortex contributes to this neutral effect of adolescent atomoxetine treatment in adult SHR. Following treatment from postnatal days 28-55 with atomoxetine (0.3 mg/kg) or vehicle, adult male SHR and control rats from Wistar-Kyoto (WKY) and Wistar (WIS) strains were trained to self-administer 0.3 mg/kg cocaine. Self-administration performance was evaluated under a PR schedule of cocaine delivery following infusion of the α2-adrenergic receptor antagonist idazoxan (0 and 10-56 μg/side) directly into prelimbic cortex. Adult SHR attained higher PR break points and had greater numbers of active lever responses and infusions than WKY and WIS. Idazoxan dose-dependently increased PR break points and active lever responses in SHR following adolescent atomoxetine vs. vehicle treatment. Behavioral changes were negligible after idazoxan pretreatment in SHR following adolescent vehicle or in WKY and WIS following adolescent atomoxetine or vehicle. α2-Adrenergic receptor blockade in prelimbic cortex of SHR masked the expected neutral effect of adolescent atomoxetine on adult cocaine self-administration behavior. Moreover, greater efficacy of acute idazoxan challenge in adult SHR after adolescent atomoxetine relative to vehicle is consistent with the idea that chronic atomoxetine may downregulate presynaptic α2A-adrenergic autoreceptors in SHR.

Perinatal phencyclidine administration decreases the density of cortical interneurons and increases the expression of neuregulin-1.

PubMed

Radonjić, Nevena V; Jakovcevski, Igor; Bumbaširević, Vladimir; Petronijević, Nataša D

2013-06-01

Perinatal phencyclidine (PCP) administration in rat blocks the N-methyl D-aspartate receptor (NMDAR) and causes symptoms reminiscent of schizophrenia in human. A growing body of evidence suggests that alterations in γ-aminobutyric acid (GABA) interneuron neurotransmission may be associated with schizophrenia. Neuregulin-1 (NRG-1) is a trophic factor important for neurodevelopment, synaptic plasticity, and wiring of GABA circuits. The aim of this study was to determine the long-term effects of perinatal PCP administration on the projection and local circuit neurons and NRG-1 expression in the cortex and hippocampus. Rats were treated on postnatal day 2 (P2), P6, P9, and P12 with either PCP (10 mg/kg) or saline. Morphological studies and determination of NRG-1 expression were performed at P70. We demonstrate reduced densities of principal neurons in the CA3 and dentate gyrus (DG) subregions of the hippocampus and a reduction of major interneuronal populations in all cortical and hippocampal regions studied in PCP-treated rats compared with controls. For the first time, we show the reduced density of reelin- and somatostatin-positive cells in the cortex and hippocampus of animals perinatally treated with PCP. Furthermore, an increase in the numbers of perisomatic inhibitory terminals around the principal cells was observed in the motor cortex and DG. We also show that perinatal PCP administration leads to an increased NRG-1 expression in the cortex and hippocampus. Taken together, our findings demonstrate that perinatal PCP administration increases NRG-1 expression and reduces the number of projecting and local circuit neurons, revealing complex consequences of NMDAR blockade.

Nutrition in brain development and aging: role of essential fatty acids.

PubMed

Uauy, Ricardo; Dangour, Alan D

2006-05-01

The essential fatty acids (EFAs), particularly the n-3 long-chain polyunsaturated fatty acids (LCPs), are important for brain development during both the fetal and postnatal period. They are also increasingly seen to be of value in limiting the cognitive decline during aging. EFA deficiency was first shown over 75 years ago, but the more subtle effects of the n-3 fatty acids in terms of skin changes, a poor response to linoleic acid supplementation, abnormal visual function, and peripheral neuropathy were only discovered later. Both n-3 and n-6 LCPs play important roles in neuronal growth, development of synaptic processing of neural cell interaction, and expression of genes regulating cell differentiation and growth. The fetus and placenta are dependent on maternal EFA supply for their growth and development, with docosahexaenomic acid (DHA)-supplemented infants showing significantly greater mental and psychomotor development scores (breast-fed children do even better). Dietary DHA is needed for the optimum functional maturation of the retina and visual cortex, with visual acuity and mental development seemingly improved by extra DHA. Aging is also associated with decreased brain levels of DHA: fish consumption is associated with decreased risk of dementia and Alzheimer's disease, and the reported daily use of fish-oil supplements has been linked to improved cognitive function scores, but confirmation of these effects is needed.

A meta-analysis of nutrition interventions on mental development of children under-two in low- and middle-income countries.

PubMed

Larson, Leila Margaret; Yousafzai, Aisha K

2017-01-01

Interventions to improve nutritional status of young children in low- and middle-income countries (LMIC) may have the added benefit of improving their mental and motor development. This meta-analysis updates and goes beyond previous ones by answering two important questions: (1) do prenatal and postnatal nutritional inputs improve mental development, and (2) are effects on mental development associated with two theoretically interesting mediators namely physical growth and motor development? The meta-analysis of articles on Medline, PsycINFO, Global Health and Embase was limited to randomized trials in LMICs, with mental development of children from birth to age two years as an outcome. The initial yield of 2689 studies was reduced to 33; 12 received a global quality rating of strong. Of the 10 prenatal and 23 postnatal nutrition interventions, the majority used zinc, iron/folic acid, vitamin A or multiple micronutrients, with a few evaluating macronutrients. The weighted mean effect size, Cohen's d (95% CI) for prenatal and postnatal nutrition interventions on mental development was 0.042 (-0.0084, 0.092) and 0.076 (0.019, 0.13), respectively. Postnatal supplements consisting of macronutrients yielded an effect size d (95% CI) of 0.14 (0.0067, 0.27), multiple micronutrients 0.082 (-0.012, 0.18) and single micronutrients 0.058 (-0.0015, 0.12). Motor development, but not growth status, effect sizes were significantly associated with mental development in postnatal interventions. In summary, nutrition interventions had small effects on mental development. Future studies might have greater effect if they addressed macronutrient deficiencies combined with child stimulation and hygiene and sanitation interventions. © 2015 John Wiley & Sons Ltd.

Cognition and behavioural development in early childhood: the role of birth weight and postnatal growth

PubMed Central

Huang, Cheng; Martorell, Reynaldo; Ren, Aiguo; Li, Zhiwen

2013-01-01

Background We evaluate the relative importance of birth weight and postnatal growth for cognition and behavioural development in 8389 Chinese children, 4–7 years of age. Method Weight was the only size measure available at birth. Weight, height, head circumference and intelligence quotient (IQ) were measured between 4 and 7 years of age. Z-scores of birth weight and postnatal conditional weight gain to 4–7 years, as well as height and head circumference at 4–7 years of age, were the exposure variables. Z-scores of weight at 4–7 years were regressed on birth weight Z-scores, and the residual was used as the measure of postnatal conditional weight gain. The outcomes were child’s IQ, measured by the Chinese Wechsler Young Children Scale of Intelligence, as well as internalizing behavioural problems, externalizing behavioural problems and other behavioural problems, evaluated by the Child Behavior Checklist 4–18. Multivariate regressions were conducted to investigate the relationship of birth weight and postnatal growth variables with the outcomes, separately for preterm children and term children. Results Both birth weight and postnatal weight gain were associated with IQ among term children; 1 unit increment in Z-score of birth weight (∼450 g) was associated with an increase of 1.60 [Confidence interval (CI): 1.18–2.02; P < 0.001] points in IQ, and 1 unit increment in conditional postnatal weight was associated with an increase of 0.46 (CI: 0.06–0.86; P = 0.02) points in IQ, after adjustment for confounders; similar patterns were observed when Z-scores of postnatal height and head circumference at age 4–7 years were used as alternative measurements of postnatal growth. Effect sizes of relationships with IQ were smaller than 0.1 of a standard deviation in all cases. Neither birth weight nor postnatal growth indicators were associated with behavioural outcomes among term children. In preterm children, neither birth weight nor postnatal growth measures were associated with IQ or behavioural outcomes. Conclusions Both birth weight and postnatal growth were associated with IQ but not behavioural outcomes for Chinese term children aged 4–7 years, but the effect sizes were small. No relation between either birth weight or postnatal growth and cognition or behavioural outcomes was observed among preterm children aged 4–7 years. PMID:23243117

The development of two postnatal health instruments: one for mothers (M-PHI) and one for fathers (F-PHI) to measure health during the first year of parenting.

PubMed

Jones, G L; Morrell, C J; Cooke, J M; Speier, D; Anumba, D; Stewart-Brown, S

2011-09-01

To develop and psychometrically evaluate two questionnaires measuring both positive and negative postnatal health of mothers (M-PHI) and fathers (F-PHI) during the first year of parenting. The M-PHI and the F-PHI were developed in four stages. Stage 1: Postnatal women's focus group (M-PHI) and postnatal fathers' postal questionnaire (F-PHI); Stage 2: Qualitative interviews; Stage 3: Pilot postal survey and main postal survey; and Stage 4: Test-retest postal survey. The M-PHI consisted of a 29-item core questionnaire with six main scales and five conditional scales. The F-PHI consisted of a 27-item questionnaire with six main scales. All scales achieved good internal reliability (Cronbach's α 0.66-0.87 for M-PHI, 0.72-0.90 for F-PHI). Intraclass correlation coefficients demonstrated high test-retest reliability (0.60-0.88). Correlation coefficients supported the criterion validity of the M-PHI and the F-PHI when tested against the Short-Form-12 (SF-12), Edinburgh Postnatal Depression Scale (EPDS) and the Warwick and Edinburgh Mental Well-Being Scale (WEMWBS). The M-PHI and F-PHI are valid, reliable, parent-generated instruments. These unique instruments will be invaluable for practitioners wishing to promote family-centred care and for trialists and other researchers requiring a validated instrument to measure both positive and negative health during the first postnatal year, as to date no such measurement has existed.

Sex differences in corticolimbic dopamine and serotonin systems in the rat and the effect of postnatal handling.

PubMed

Duchesne, Annie; Dufresne, Marc M; Sullivan, Ron M

2009-03-17

Stress-related psychopathology is particularly prevalent in women, although the neurobiological reason(s) for this are unclear. Dopamine (DA) and serotonin (5-HT) systems however, are known to play important adaptive roles in stress and emotion regulation. The aims of the present study included examination of sex differences in stress-related behaviour and neuroendocrine function as well as post mortem neurochemistry, with the main hypothesis that corticolimbic DA and 5-HT systems would show greater functional activity in males than females. Long-Evans rats of both sexes were employed. Additional factors incorporated included differential postnatal experience (handled vs. nonhandled) and adult mild stress experience (acute vs. repeated (5) restraint). Regional neurochemistry measures were conducted separately for left and right hemispheres. Behaviourally, females showed more exploratory behaviour than males in the elevated plus maze and an openfield/holeboard apparatus. Females also exhibited significantly higher levels of adrenocorticotrophic hormone and corticosterone at all time points in response to restraint stress than males across treatment conditions, although both sexes showed similar habituation in stress-induced ACTH activation with repeated mild stress. Neurochemically, females had significantly higher levels of DA (in ventromedial prefrontal cortex (vmPFC), insular cortex and n. accumbens) and 5-HT (in vmPFC, amygdala, dorsal hippocampus and insula) than males. In contrast, males had higher levels of the DA metabolite DOPAC or DOPAC/DA ratios than females in all five regions and higher levels of the 5-HT metabolite 5-HIAA or 5-HIAA/5-HT ratios in vmPFC, amygdala and insula, suggesting greater neurotransmitter utilization in males. Moreover, handling treatment induced a significant male-specific upregulation of 5-HT metabolism in all regions except n. accumbens. Given the adaptive role of 5-HT and DAergic neurotransmission in stress and emotion regulation, the intrinsic sex differences we report in the functional status of these systems across conditions, may be highly relevant to the differential vulnerability to disorders of stress and emotion regulation.

Effects of enriched environment on alterations in the prefrontal cortex GFAP- and S100B-immunopositive astrocytes and behavioral deficits in MK-801-treated rats.

PubMed

Rahati, M; Nozari, M; Eslami, H; Shabani, M; Basiri, M

2016-06-21

A plethora of studies have indicated that enriched environment (EE) paradigm provokes plastic and morphological changes in astrocytes with accompanying increments of their density and positively affects the behavior of rodents. We also previously documented that EE could be employed to preclude several behavioral abnormalities, mainly cognitive deficits, attributed to postnatal N-methyl-d-aspartate (NMDA) receptor antagonist (MK-801) treatment, as a rodent model of schizophrenia (SCH) aspects. Given this, the current study quantitatively investigated the number of cells, presumed to be astrocytes, expressing two astroglia-associated proteins (S100B and glial fibrillary acidic protein (GFAP)) by immunohistochemistry in the prefrontal cortex (PFC), along with anxiety and passive avoidance (PA) learning behaviors by utilizing elevated plus maze (EPM) and shuttle-box tests, in MK-801-treated male wistar rats submitted to EE and non-EE rats. Following a treatment regime of sub-chronic MK-801 (1.0mg/kg i.p. daily for five consecutive days from postnatal day (P) 6), S-100B-positive cells and anxiety level were markedly increased, while the GFAP-positive cells and PA learning were notably attenuated. The trend of diminished GFAP-immunopositive cells and elevated S100B-immunostained cells in the PFC was reversed in the SCH-like rats by exposure of animals to EE, commencing from birth up to the time of experiments on P28-85. Additionally, EE exhibited an ameliorating effect on the behavioral abnormalities evoked by MK-801. Overall, present findings support that improper astrocyte functioning and behavioral changes, reminiscent of the many facets of SCH, occur consequential to repetitive administration of MK-801 and that raising rat pups in an EE mitigates these alterations. Copyright © 2016 IBRO. Published by Elsevier Ltd. All rights reserved.

Postnatally acquired cytomegalovirus infection via breast milk: effects on hearing and development in preterm infants.

PubMed

Vollmer, Brigitte; Seibold-Weiger, Karin; Schmitz-Salue, Christine; Hamprecht, Klaus; Goelz, Rangmar; Krageloh-Mann, Ingeborg; Speer, Christian P

2004-04-01

In preterm infants there is a high risk of transmission of cytomegalovirus (CMV) via breast milk from seropositive mothers with reactivation of the virus during lactation. There is little information about the long term sequel of early postnatally acquired CMV infection in pre-term infants. This study aimed to investigate whether there was an increased frequency of impaired neurodevelopmental outcome and sensorineural hearing loss in preterm infants with postnatally acquired CMV infection through transmission by CMV-positive breast milk. Twenty-two preterm infants [median birth weight, 1020 g (range, 600 to 1870 g); median gestational age, 27.6 weeks (range, 23.6 to 32 weeks] with early postnatally acquired CMV infection by breast-feeding (onset of viruria between Days 23 and 190 postnatally) were compared with 22 CMV-negative preterm infants individually matched for gestational age, birth weight, gender, intracranial hemorrhage and duration of ventilation. At 2 to 4.5 years of age, follow-up assessments were conducted consisting of neurologic examination, neurodevelopmental assessment and detailed audiologic tests. None of the children had sensorineural hearing loss. There was no difference between the groups with regard to neurologic, speech and language or motor development. The results of this study suggest that early postnatally acquired CMV infection via CMV-positive breast milk does not have a negative effect on neurodevelopment and hearing in this group of patients. Because we studied a small number of infants, further follow-up studies are warranted in preterm infants with early postnatally acquired CMV infection.

Extensive alternative splicing transitions during postnatal skeletal muscle development are required for calcium handling functions

PubMed Central

Brinegar, Amy E; Xia, Zheng; Loehr, James Anthony; Li, Wei; Rodney, George Gerald

2017-01-01

Postnatal development of skeletal muscle is a highly dynamic period of tissue remodeling. Here, we used RNA-seq to identify transcriptome changes from late embryonic to adult mouse muscle and demonstrate that alternative splicing developmental transitions impact muscle physiology. The first 2 weeks after birth are particularly dynamic for differential gene expression and alternative splicing transitions, and calcium-handling functions are significantly enriched among genes that undergo alternative splicing. We focused on the postnatal splicing transitions of the three calcineurin A genes, calcium-dependent phosphatases that regulate multiple aspects of muscle biology. Redirected splicing of calcineurin A to the fetal isoforms in adult muscle and in differentiated C2C12 slows the timing of muscle relaxation, promotes nuclear localization of calcineurin target Nfatc3, and/or affects expression of Nfatc transcription targets. The results demonstrate a previously unknown specificity of calcineurin isoforms as well as the broader impact of alternative splicing during muscle postnatal development. PMID:28826478

Determinants of postnatal care non-utilization among women in Nigeria.

PubMed

Somefun, Oluwaseyi Dolapo; Ibisomi, Latifat

2016-01-11

Although, there are several programs in place in Nigeria to ensure maternal and child health, maternal and neonatal mortality rates remain high with maternal mortality rates being 576/100,000 and neonatal mortality rates at 37/1000 live births (NDHS, 2013). While there are many studies on the utilization of maternal health services such as antenatal care and skilled delivery at birth, studies on postnatal care are limited. Therefore, the aim of this study is to examine the factors associated with the non-utilization of postnatal care among mothers in Nigeria using the Nigeria Demographic and Health Survey (NDHS) 2013. For analysis, the postnatal care uptake for 19,418 children born in the 5 years preceding the survey was considered. The dependent variable was a composite variable derived from a list of questions on postnatal care. A multinomial logistic regression model was applied to examine the adjusted and unadjusted determinants of non-utilization of postnatal care. Results from this study showed that 63% of the mothers of the 19,418 children did not utilize postnatal care services in the period examined. About 42% of the study population between 25 and 34 years did not utilize postnatal care and 61% of the women who did not utilize postnatal care had no education. Results from multinomial logistic regression show that antenatal care use, distance, education, place of delivery, region and wealth status are significantly associated with the non-utilization of postnatal care services. This study revealed the low uptake of postnatal care service in Nigeria. To increase mothers' utilization of postnatal care services and improve maternal and child health in Nigeria, interventions should be targeted at women in remote areas who don't have access to services and developing mobile clinics. In addition, it is crucial that steps should be taken on educating women. This would have a significant influence on their perceptions about the use of postnatal care services in Nigeria.

Diversification of intrinsic motoneuron electrical properties during normal development and botulinum toxin-induced muscle paralysis in early postnatal mice.

PubMed

Nakanishi, S T; Whelan, P J

2010-05-01

During early postnatal development, between birth and postnatal days 8-11, mice start to achieve weight-bearing locomotion. In association with the progression of weight-bearing locomotion there are presumed developmental changes in the intrinsic electrical properties of spinal -motoneurons. However, these developmental changes in the properties of -motoneuron properties have not been systematically explored in mice. Here, data are presented documenting the developmental changes of selected intrinsic motoneuron electrical properties, including statistically significant changes in action potential half-width, intrinsic excitability and diversity (quantified as coefficient of variation) of rheobase current, afterhyperpolarization half-decay time, and input resistance. In various adult mammalian preparations, the maintenance of intrinsic motoneuron electrical properties is dependent on activity and/or transmission-sensitive motoneuron-muscle interactions. In this study, we show that botulinum toxin-induced muscle paralysis led to statistically significant changes in the normal development of intrinsic motoneuron electrical properties in the postnatal mouse. This suggests that muscle activity during early neonatal life contributes to the development of normal motoneuron electrical properties.

Early life exposure to environmental tobacco smoke alters immune response to asbestos via a shift in inflammatory phenotype resulting in increased disease development.

PubMed

Brown, Traci Ann; Holian, Andrij; Pinkerton, Kent E; Lee, Joong Won; Cho, Yoon Hee

2016-07-01

Asbestos in combination with tobacco smoke exposure reportedly leads to more severe physiological consequences than asbestos alone; limited data also show an increased disease risk due to environmental tobacco smoke (ETS) exposure. Environmental influences during gestation and early lung development can result in physiological changes that alter risk for disease development throughout an individual's lifetime. Therefore, maternal lifestyle may impact the ability of offspring to subsequently respond to environmental insults and alter overall disease susceptibility. In this study, we examined the effects of exposure to ETS in utero and during early postnatal development on asbestos-related inflammation and disease in adulthood. ETS exposure in utero appeared to shift inflammation towards a Th2 phenotype, via suppression of Th1 inflammatory cytokine production. This effect was further pronounced in mice exposed to ETS in utero and during early postnatal development. In utero ETS exposure led to increased collagen deposition, a marker of fibrotic disease, when the offspring was later exposed to asbestos, which was further increased with additional ETS exposure during early postnatal development. These data suggest that ETS exposure in utero alters the immune responses and leads to greater disease development after asbestos exposure, which is further exacerbated when exposure to ETS continues during early postnatal development.

FGF-2 signal promotes proliferation of cerebellar progenitor cells and their oligodendrocytic differentiation at early postnatal stage

DOE Office of Scientific and Technical Information (OSTI.GOV)

Naruse, Masae; Shibasaki, Koji; Ishizaki, Yasuki, E-mail: yasukiishizaki@gunma-u.ac.jp

The origins and developmental regulation of cerebellar oligodendrocytes are largely unknown, although some hypotheses of embryonic origins have been suggested. Neural stem cells exist in the white matter of postnatal cerebellum, but it is unclear whether these neural stem cells generate oligodendrocytes at postnatal stages. We previously showed that cerebellar progenitor cells, including neural stem cells, widely express CD44 at around postnatal day 3. In the present study, we showed that CD44-positive cells prepared from the postnatal day 3 cerebellum gave rise to neurospheres, while CD44-negative cells prepared from the same cerebellum did not. These neurospheres differentiated mainly into oligodendrocytesmore » and astrocytes, suggesting that CD44-positive neural stem/progenitor cells might generate oligodendrocytes in postnatal cerebellum. We cultured CD44-positive cells from the postnatal day 3 cerebellum in the presence of signaling molecules known as mitogens or inductive differentiation factors for oligodendrocyte progenitor cells. Of these, only FGF-2 promoted survival and proliferation of CD44-positive cells, and these cells differentiated into O4+ oligodendrocytes. Furthermore, we examined the effect of FGF-2 on cerebellar oligodendrocyte development ex vivo. FGF-2 enhanced proliferation of oligodendrocyte progenitor cells and increased the number of O4+ and CC1+ oligodendrocytes in slice cultures. These results suggest that CD44-positive cells might be a source of cerebellar oligodendrocytes and that FGF-2 plays important roles in their development at an early postnatal stage. - Highlights: • CD44 is expressed in cerebellar neural stem/progenitor cells at postnatal day 3 (P3). • FGF-2 promoted proliferation of CD44-positive progenitor cells from P3 cerebellum. • FGF-2 promoted oligodendrocytic differentiation of CD44-positive progenitor cells. • FGF-2 increased the number of oligodendrocytes in P3 cerebellar slice culture.« less

Genetic mapping of Foxb1-cell lineage shows migration from caudal diencephalon to telencephalon and lateral hypothalamus

PubMed Central

Zhao, Tianyu; Szabó, Nora; Ma, Jun; Luo, Lingfei; Zhou, Xunlei; Alvarez-Bolado, Gonzalo

2008-01-01

The hypothalamus is a brain region with vital functions, and alterations in its development can cause human disease. However, we still do not have a complete description of how this complex structure is put together during embryonic and early postnatal stages. Radially oriented, outside-in migration of cells is prevalent in the developing hypothalamus. In spite of this, cell contingents from outside the hypothalamus as well as tangential hypothalamic migrations also have an important role. Here we study migrations in the hypothalamic primordium by genetically labeling the Foxb1 diencephalic lineage. Foxb1 is a transcription factor gene expressed in the neuroepithelium of the developing neural tube with a rostral expression boundary between caudal and rostral diencephalon, and therefore appropriate for marking migrations from caudal levels into the hypothalamus. We have found a large, longitudinally oriented migration stream apparently originating in the thalamic region and following an axonal bundle to end in the anterior portion of the lateral hypothalamic area. Additionally, we have mapped a specific expansion of the neuroepithelium into the rostral diencephalon. The expanded neuroepithelium generates abundant neurons for the medial hypothalamus at the tuberal level. Finally, we have uncovered novel diencephalon-to-telencephalon migrations into septum, piriform cortex and amygdala. PMID:19046377

Isolation and characterization of string-forming female germline stem cells from ovaries of neonatal mice.

PubMed

Liu, Jing; Shang, Dantong; Xiao, Yao; Zhong, Pei; Cheng, Hanhua; Zhou, Rongjia

2017-09-29

Germline stem cells are essential in the generation of both male and female gametes. In mammals, the male testis produces sperm throughout the entire lifetime, facilitated by testicular germline stem cells. Oocyte renewal ceases in postnatal or adult life in mammalian females, suggesting that germline stem cells are absent from the mammalian ovary. However, studies in mice, rats, and humans have recently provided evidence for ovarian female germline stem cells (FGSCs). A better understanding of the role of FGSCs in ovaries could help improve fertility treatments. Here, we developed a rapid and efficient method for isolating FGSCs from ovaries of neonatal mice. Notably, our FGSC isolation method could efficiently isolate on average 15 cell "strings" per ovary from mice at 1-3 days postpartum. FGSCs isolated from neonatal mice displayed the string-forming cell configuration at mitosis ( i.e. a "stringing" FGSC (sFGSC) phenotype) and a disperse phenotype in postnatal mice. We also found that sFGSCs undergo vigorous mitosis especially at 1-3 days postpartum. After cell division, the sFGSC membranes tended to be connected to form sFGSCs. Moreover, F-actin filaments exhibited a cell-cortex distribution in sFGSCs, and E-cadherin converged in cell-cell connection regions, resulting in the string-forming morphology. Our new method provides a platform for isolating FGSCs from the neonatal ovary, and our findings indicate that FGCSs exhibit string-forming features in neonatal mice. The sFGSCs represent a valuable resource for analysis of ovary function and an in vitro model for future clinical use to address ovarian dysfunction. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

Regulation of alternative splicing of Slo K+ channels in adrenal and pituitary during the stress-hyporesponsive period of rat development.

PubMed

Lai, Guey-Jen; McCobb, David P

2006-08-01

Stress triggers release of ACTH from the pituitary, glucocorticoids from the adrenal cortex, and epinephrine from the adrenal medulla. Although functions differ, these hormone systems interact in many ways. Previous evidence indicates that pituitary and steroid hormones regulate alternative splicing of the Slo gene at the stress axis-regulated exon (STREX), with functional implications for the calcium-activated K+ channels prominent in adrenal medullary and pituitary cells. Here we examine the role of corticosterone in Slo splicing regulation in pituitary and adrenal tissues during the stress-hyporesponsive period of early rat postnatal life. The sharp drop in plasma corticosterone (CORT) that defines this period offers a unique opportunity to test CORT's role in Slo splicing. We report that in both adrenal and pituitary tissues, the percentage of Slo transcripts having STREX declines and recovers in parallel with CORT. Moreover, addition of 500 nm CORT to cultures of anterior pituitary cells from 13-, 21-, and 30-d postnatal animals increased the percentage of Slo transcripts with STREX, whereas 20 microm CORT reduced STREX representation. Applied to adrenal chromaffin cells, 20 microm CORT decreased STREX inclusion, whereas neither 500 nm nor 2 microm had any effect. The mineralocorticoid receptor antagonist RU28318 abolished the effect of 500 nm CORT on splicing in pituitary cells, whereas the glucocorticoid receptor antagonist RU38486 blocked the effect of 20 microm CORT on adrenal chromaffin cells. These results support the hypothesis that the abrupt, transient drop in CORT during the stress-hyporesponsive period drives the transient decline in STREX splice variant representation in pituitary, but not adrenal.

Anandamide-CB1 Receptor Signaling Contributes to Postnatal Ethanol-Induced Neonatal Neurodegeneration, Adult Synaptic and Memory Deficits

PubMed Central

Subbanna, Shivakumar; Shivakumar, Madhu; Psychoyos, Delphine; Xie, Shan; Basavarajappa, Balapal S.

2013-01-01

The transient exposure of immature rodents to ethanol during postnatal day 7 (P7), which is comparable to the third trimester human pregnancy, induces synaptic dysfunctions. However, the molecular mechanisms underlying these dysfunctions are still poorly understood. Although the endocannabinoid system has been shown to be an important modulator of ethanol sensitivity in adult mice, its potential role in synaptic dysfunctions in mice exposed to ethanol during early brain development is not examined. In this study, we investigated the potential role of endocannabinoids and the cannabinoid receptor type 1 (CB1R) in neonatal neurodegeneration and adult synaptic dysfunctions in mice exposed to ethanol at P7. Ethanol treatment at P7, which induces neurodegeneration, increased anandamide (AEA) but not 2-arachidonylglycerol biosynthesis and CB1R protein expression in the hippocampus and cortex, two brain areas that are important for memory formation and storage, respectively. N-arachidonoyl phosphatidylethanolamine-phospholipase D (NAPE-PLD), glycerophosphodiesterase (GDE1) and CB1Rs protein expression were enhanced by transcriptional activation of the genes encoding NAPE-PLD, GDE1 and CB1R proteins respectively. In addition, ethanol inhibited ERK1/2 and AKT phosphorylation. The blockade of CB1Rs prior to ethanol treatment at P7 relieved ERK1/2 but not AKT phosphorylation and prevented neurodegeneration. CB1R knockout mice exhibited no ethanol-induced neurodegeneration and inhibition of ERK1/2-phosphorylation. The protective effects of CB1R blockade through pharmacological or genetic deletion resulted in normal adult synaptic plasticity and novel object recognition memory in mice exposed to ethanol at P7. The AEA/CB1R/pERK1/2 signaling pathway may be directly responsible for the synaptic and memory deficits associated with fetal alcohol spectrum disorders. PMID:23575834

Rapid Redistribution of Synaptic PSD-95 in the Neocortex In Vivo

PubMed Central

Bureau, Ingrid; Svoboda, Karel

2006-01-01

Most excitatory synapses terminate on dendritic spines. Spines vary in size, and their volumes are proportional to the area of the postsynaptic density (PSD) and synaptic strength. PSD-95 is an abundant multi-domain postsynaptic scaffolding protein that clusters glutamate receptors and organizes the associated signaling complexes. PSD-95 is thought to determine the size and strength of synapses. Although spines and their synapses can persist for months in vivo, PSD-95 and other PSD proteins have shorter half-lives in vitro, on the order of hours. To probe the mechanisms underlying synapse stability, we measured the dynamics of synaptic PSD-95 clusters in vivo. Using two-photon microscopy, we imaged PSD-95 tagged with GFP in layer 2/3 dendrites in the developing (postnatal day 10–21) barrel cortex. A subset of PSD-95 clusters was stable for days. Using two-photon photoactivation of PSD-95 tagged with photoactivatable GFP (paGFP), we measured the time over which PSD-95 molecules were retained in individual spines. Synaptic PSD-95 turned over rapidly (median retention times τ r ~ 22–63 min from P10–P21) and exchanged with PSD-95 in neighboring spines by diffusion. PSDs therefore share a dynamic pool of PSD-95. Large PSDs in large spines captured more diffusing PSD-95 and also retained PSD-95 longer than small PSDs. Changes in the sizes of individual PSDs over days were associated with concomitant changes in PSD-95 retention times. Furthermore, retention times increased with developmental age (τ r ~ 100 min at postnatal day 70) and decreased dramatically following sensory deprivation. Our data suggest that individual PSDs compete for PSD-95 and that the kinetic interactions between PSD molecules and PSDs are tuned to regulate PSD size. PMID:17090216

Down, But Not Out: Partial Elimination of Androgen Receptors in the Male Mouse Brain Does Not Affect Androgenic Regulation of Anxiety or HPA Activity.

PubMed

Chen, Chieh V; Brummet, Jennifer L; Jordan, Cynthia L; Breedlove, S Marc

2016-02-01

We previously found that androgen receptor (AR) activity mediates two effects of T in adult male mice: reduction of anxiety-like behaviors and dampening of the hypothalamic-pituitary-adrenal response to stress. To determine whether brain ARs mediate these effects, we used the Cre/loxP technology seeking to disable AR throughout the central nervous system (CNS). Female mice carrying the floxed AR allele (ARlox) were crossed with males carrying cre recombinase transgene controlled by the nestin promoter (NesCre), producing cre in developing neurons and glia. Among male offspring, four genotypes resulted: males carrying ARlox and NesCre (NesARko), and three control groups (wild types, NesCre, and ARlox). Reporter mice indicated ubiquitous Cre expression throughout the CNS. Nevertheless, AR immunocytochemistry in NesARko mice revealed efficient knockout (KO) of AR in some brain regions (hippocampus and medial prefrontal cortex [mPFC]), but not others. Substantial AR protein was seen in the amygdala and hypothalamus among other regions, whereas negligible AR remained in others like the bed nucleus of the stria terminalis and dorsal periaqueductal gray. This selective KO allowed for testing the role of AR in hippocampus and mPFC. Males were castrated and implanted with T at postnatal day 60 before testing on postnatal day 90-100. In contrast with males with global KO of AR, T still modulated anxiety-related behavior and hypothalamic-pituitary-adrenal activity in NesARko males. These results leave open the possibility that AR acting in the CNS mediates these effects of T, but demonstrate that AR is not required in the hippocampus or mPFC for T's anxiolytic effects.

Down, But Not Out: Partial Elimination of Androgen Receptors in the Male Mouse Brain Does Not Affect Androgenic Regulation of Anxiety or HPA Activity

PubMed Central

Brummet, Jennifer L.; Jordan, Cynthia L.; Breedlove, S. Marc

2016-01-01

We previously found that androgen receptor (AR) activity mediates two effects of T in adult male mice: reduction of anxiety-like behaviors and dampening of the hypothalamic-pituitary-adrenal response to stress. To determine whether brain ARs mediate these effects, we used the Cre/loxP technology seeking to disable AR throughout the central nervous system (CNS). Female mice carrying the floxed AR allele (ARlox) were crossed with males carrying cre recombinase transgene controlled by the nestin promoter (NesCre), producing cre in developing neurons and glia. Among male offspring, four genotypes resulted: males carrying ARlox and NesCre (NesARko), and three control groups (wild types, NesCre, and ARlox). Reporter mice indicated ubiquitous Cre expression throughout the CNS. Nevertheless, AR immunocytochemistry in NesARko mice revealed efficient knockout (KO) of AR in some brain regions (hippocampus and medial prefrontal cortex [mPFC]), but not others. Substantial AR protein was seen in the amygdala and hypothalamus among other regions, whereas negligible AR remained in others like the bed nucleus of the stria terminalis and dorsal periaqueductal gray. This selective KO allowed for testing the role of AR in hippocampus and mPFC. Males were castrated and implanted with T at postnatal day 60 before testing on postnatal day 90–100. In contrast with males with global KO of AR, T still modulated anxiety-related behavior and hypothalamic-pituitary-adrenal activity in NesARko males. These results leave open the possibility that AR acting in the CNS mediates these effects of T, but demonstrate that AR is not required in the hippocampus or mPFC for T's anxiolytic effects. PMID:26562258

Effects of Transforming Growth Factor Beta 1 in Cerebellar Development: Role in Synapse Formation

PubMed Central

Araujo, Ana P. B.; Diniz, Luan P.; Eller, Cristiane M.; de Matos, Beatriz G.; Martinez, Rodrigo; Gomes, Flávia C. A.

2016-01-01

Granule cells (GC) are the most numerous glutamatergic neurons in the cerebellar cortex and represent almost half of the neurons of the central nervous system. Despite recent advances, the mechanisms of how the glutamatergic synapses are formed in the cerebellum remain unclear. Among the TGF-β family, TGF-beta 1 (TGF-β1) has been described as a synaptogenic molecule in invertebrates and in the vertebrate peripheral nervous system. A recent paper from our group demonstrated that TGF-β1 increases the excitatory synapse formation in cortical neurons. Here, we investigated the role of TGF-β1 in glutamatergic cerebellar neurons. We showed that the expression profile of TGF-β1 and its receptor, TβRII, in the cerebellum is consistent with a role in synapse formation in vitro and in vivo. It is low in the early postnatal days (P1–P9), increases after postnatal day 12 (P12), and remains high until adulthood (P30). We also found that granule neurons express the TGF-β receptor mRNA and protein, suggesting that they may be responsive to the synaptogenic effect of TGF-β1. Treatment of granular cell cultures with TGF-β1 increased the number of glutamatergic excitatory synapses by 100%, as shown by immunocytochemistry assays for presynaptic (synaptophysin) and post-synaptic (PSD-95) proteins. This effect was dependent on TβRI activation because addition of a pharmacological inhibitor of TGF-β, SB-431542, impaired the formation of synapses between granular neurons. Together, these findings suggest that TGF-β1 has a specific key function in the cerebellum through regulation of excitatory synapse formation between granule neurons. PMID:27199658

Maternal deprivation decelerates postnatal morphological lung development of F344 rats.

PubMed

Hupa, Katharina Luise; Schmiedl, Andreas; Pabst, Reinhard; Von Hörsten, Stephan; Stephan, Michael

2014-02-01

Intensive medical care at premature born infants is often associated with separation of neonates from their mothers. Here, early artificial prolonged separation of rat pups from their dams (Maternal Deprivation, MD) was used to study potential impact on morphological lung maturation. Furthermore, we investigated the influence of an endogenous deficiency of the neuropeptide-cleaving dipeptidyl peptidase IV (DPP4), since the effects of MD are known to be partly mediated via neuropeptidergic effects, hypothesizing that MD will lead to a retardation of postnatal lung development, DPP4-dependendly. We used wild type and CD26/DPP4 deficient rats. For MD, the dam was placed each day into a separate cage for 2 h, while the pups remained in the nest on their own. Morphological lung maturation and cell proliferation at the postnatal days 7, 10, 14, and 21 were determined morphometrically. Maternally deprived wild types showed a retarded postnatal lung development compared with untreated controls in both substrains. During alveolarization, an increased thickness of alveolar septa and a decreased surface of septa about 50% were found. At the end of the morphological lung maturation, the surface of the alveolar septa was decreased at about 25% and the septal thickness remained increased about 20%. The proliferation rate was also decreased about 50% on day 14. However, the MD induced effects were less pronounced in DPP4-deficient rats, due to a significant deceleration already induced by DPP4-deficiency. Thus, MD as a model for postnatal stress experience influences remarkably postnatal development of rats, which is significantly modulated by the DPP4-system. Copyright © 2013 Wiley Periodicals, Inc.

SCG postnatal remodelling--hypertrophy and neuron number stability--in Spix's yellow-toothed cavies (Galea spixii).

PubMed

Ladd, Aliny A B Lobo; Ladd, Fernando V Lobo; da Silva, Andrea A P; Oliveira, Moacir F; de Souza, Romeu R; Coppi, Antonio A

2012-04-01

Whilst a fall in neuron numbers seems a common pattern during postnatal development, several authors have nonetheless reported an increase in neuron number, which may be associated with any one of a number of possible processes encapsulating either neurogenesis or late maturation and incomplete differentiation. Recent publications have thus added further fuel to the notion that a postnatal neurogenesis may indeed exist in sympathetic ganglia. In the light of these uncertainties surrounding the effects exerted by postnatal development on the number of superior cervical ganglion (SCG) neurons, we have used state-of-the-art design-based stereology to investigate the quantitative structure of SCG at four distinct timepoints after birth, viz., 1-3 days, 1 month, 12 months and 36 months. The main effects exerted by ageing on the SCG structure were: (i) a 77% increase in ganglion volume; (ii) stability in the total number of the whole population of SCG nerve cells (no change--either increase or decrease) during post-natal development; (iii) a higher proportion of uninucleate neurons to binucleate neurons only in newborn animals; (iv) a 130% increase in the volume of uninucleate cell bodies; and (v) the presence of BrdU positive neurons in animals at all ages. At the time of writing our results support the idea that neurogenesis takes place in the SCG of preás, albeit it warrants confirmation by further markers. We also hypothesise that a portfolio of other mechanisms: cell repair, maturation, differentiation and death may be equally intertwined and implicated in the numerical stability of SCG neurons during postnatal development. Copyright © 2011 ISDN. Published by Elsevier Ltd. All rights reserved.

Thrombospondin-2 Expression During Retinal Vascular Development and Neovascularization.

PubMed

Fei, Ping; Palenski, Tammy L; Wang, Shoujian; Gurel, Zafer; Hankenson, Kurt D; Sorenson, Christine M; Sheibani, Nader

2015-09-01

To determine thrombospondin-2 (TSP2) expression and its impact on postnatal retinal vascular development and retinal neovascularization. The TSP2-deficient (TSP2(-/-)) mice and a line of TSP2 reporter mice were used to assess the expression of TSP2 during postnatal retinal vascular development and neovascularization. The postnatal retinal vascularization was evaluated using immunostaining of wholemount retinas prepared at different postnatal days by collagen IV staining and/or TSP2 promoter driven green fluorescent protein (GFP) expression. The organization of astrocytes was evaluated by glial fibrillary acidic protein (GFAP) staining. Retinal vascular densities were determined using trypsin digestion preparation of wholemount retinas at 3- and 6-weeks of age. Retinal neovascularization was assessed during the oxygen-induced ischemic retinopathy (OIR). Choroidal neovascularization (CNV) was assessed using laser-induced CNV. Using the TSP2-GFP reporter mice, we observed significant expression of TSP2 mRNA in retinas of postnatal day 5 (P5) mice, which increased by P7 and remained high up to P42. Similar results were observed in retinal wholemount preparations, and western blotting for GFP with the highest level of GFP was observed at P21. In contrast to high level of mRNA at P42, the GFP fluorescence or protein level was dramatically downregulated. The primary retinal vasculature developed at a faster rate in TSP2(-/-) mice compared with TSP2(+/+) mice up to P5. However, the developing retinal vasculature in TSP2(+/+) mice caught up with that of TSP2(-/-) mice after P7. No significant differences in retinal vascular density were observed at 3- or 6-weeks of age. TSP2(-/-) mice also exhibited a similar sensitivity to the hyperoxia-mediated vessel obliteration and similar level of neovascularization during OIR as TSP2(+/+) mice. Lack of TSP2 expression minimally affected laser-induced CNV compared with TSP2(+/+) mice. Lack of TSP2 expression was associated with enhanced retinal vascularization during early postnatal days but not at late postnatal times, and minimally affected retinal and CNV. However, the utility of TSP2 as a potential therapeutic target for inhibition of ocular neovascularization awaits further investigation.

Oral methylphenidate alleviates the fine motor dysfunction caused by chronic postnatal manganese exposure in adult rats.

PubMed

Beaudin, Stéphane A; Strupp, Barbara J; Lasley, Stephen M; Fornal, Casimir A; Mandal, Shyamali; Smith, Donald R

2015-04-01

Developmental manganese (Mn) exposure is associated with motor dysfunction in children and animal models, but little is known about the underlying neurochemical mechanisms or the potential for amelioration by pharmacotherapy. We investigated whether methylphenidate (MPH) alleviates fine motor dysfunction due to chronic postnatal Mn exposure, and whether Mn exposure impairs brain extracellular dopamine (DA) and norepinephrine (NE) in the prefrontal cortex (PFC) and striatum in adult animals. Rats were orally exposed to 0 or 50 mg Mn/kg/day from postnatal day 1 until the end of the study (PND 145). The staircase test was used to assess skilled forelimb function. Oral MPH (2.5 mg/kg/day) was administered daily 1 h before staircase testing for 16 days. DA and NE levels were measured by dual probe microdialysis. Results show that Mn exposure impaired reaching and grasping skills and the evoked release of DA and NE in the PFC and striatum of adult rats. Importantly, oral MPH treatment fully alleviated the fine motor deficits in the Mn-exposed animals, but did not affect forelimb skills of control rats not exposed to Mn. These results suggest that catecholaminergic hypofunctioning in the PFC and striatum may underlie the Mn-induced fine motor dysfunction, and that oral MPH pharmacotherapy is an effective treatment approach for alleviating this dysfunction in adult animals. The therapeutic potential of MPH for the treatment of motor dysfunction in Mn-exposed children and adults appears promising pending further characterization of MPH efficacy in other functional areas (eg, attention) believed to be affected by developmental Mn exposure. © The Author 2015. Published by Oxford University Press on behalf of the Society of Toxicology. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Effect of Gestational Intake of Fisetin (3,3',4',7-Tetrahydroxyflavone) on Developmental Methyl Mercury Neurotoxicity in F1 Generation Rats.

PubMed

Jacob, Sherin; Thangarajan, Sumathi

2017-06-01

Methyl mercury (MeHg) is a developmental neurotoxin that causes irreversible cognitive damage in offspring of gestationally exposed mothers. Currently, no preventive drugs are established against MeHg developmental neurotoxicity. The neuroprotective effect of gestational administration of a flavanoid against in utero toxicity of MeHg is not explored much. Hence, the present study validated the effect of a bioactive flavanoid, fisetin, on MeHg developmental neurotoxicity outcomes in rat offspring at postnatal weaning age. Pregnant Wistar rats were simultaneously given MeHg (1.5 mg/kg b.w.) and two doses of fisetin (10 and 50 mg/kg b.w. in two separate groups) orally from gestational day (GD) 5 till parturition. Accordingly, after parturition, on postnatal day (PND) 24, weaning F 1 generation rats were studied for motor and cognitive behavioural changes. Biochemical and histopathological changes were also studied in the cerebral cortex, cerebellum and hippocampus on PND 25. Administration of fisetin during pregnancy prevented behavioural impairment due to transplacental MeHg exposure in weaning rats. Fisetin decreased the levels of oxidative stress markers, increased enzymatic and non-enzymatic antioxidant levels and increased the activity of membrane-bound ATPases and cholinergic function in F 1 generation rats. In light microscopic studies, fisetin treatment protected the specific offspring brain regions from significant morphological aberrations. Between the two doses of fisetin studied, 10 mg/kg b.w. was found to be more satisfactory and effective than 50 mg/kg b.w. The present study shows that intake of fisetin during pregnancy in rats ameliorated in utero MeHg exposure-induced neurotoxicity outcomes in postnatal weaning F 1 generation rats.

Concentration change of DA, DOPAC, Glu and GABA in brain tissues in schizophrenia developmental model rats induced by MK-801.

PubMed

Liu, Yong; Tang, Yamei; Pu, Weidan; Zhang, Xianghui; Zhao, Jingping

2011-08-01

To explore the related neurobiochemical mechanism by comparing the concentration change of dopamine (DA), dihydroxy-phenyl acetic acid (DOPAC), glutamate (Glu), and γ-aminobutyric acid (GABA) in the brain tissues in schizophrenia (SZ) developmental model rats and chronic medication model rats. A total of 60 neonatal male Spragur-Dawley (SD) rats were randomly assigned to 3 groups at the postnatal day 6: an SZ developmental rat model group (subcutaneous injection with MK-801 at the postnatal day 7-10, 0.1 mg/kg, Bid), a chronic medication model group (intraperitoneal injection at the postnatal day 47-60, 0.2 mg/kg,Qd), and a normal control group (injection with 0.9% normal saline during the corresponding periods). DA, DOPAC, Glu, and GABA of the tissue homogenate from the medial prefrontal cortex (mPFC) and hippocampus were examined with Coularray electrochemic detection by high performance liquid chromatogram technique. The utilization rate of DA and Glu was calculated. Compared with the normal control group, the concentration of DA and DOPAC in the mPFC and the hippocampus in the SZ developmental model group significantly decreased (P<0.05), and the GABA concentration and Glu utilization rate in the mPFC also decreased (P<0.05). Compared with the chronic medication model group, the DA concentration of the mPFC in the SZ developmental group decreased (P<0.05), and the DOPAC concentration and the utility rate of DA in the hippocampus also decreased (P<0.01, P<0.05, respectively). The activities of DA, Glu and GABA system decrease in the mPFC and the DA system function reduces in the hippocampus of SZ developmental rats.

Retinal dehydrogenase gene expression in stomach and small intestine of rats during postnatal development and in vitamin A deficiency.

PubMed

Bhat, P V

1998-04-17

Retinal dehydrogenase (RALDH) catalyzes the oxidation of retinal to all-trans and 9-cis retinoic acid, which function as ligands controlling RAR and RXR nuclear receptor-signaling pathways. We have recently shown the expression of RALDH transcript in the stomach and small intestine by reverse transcription polymerase chain reaction [Bhat, P.V., Labrecque J., Dumas, F., Lacroix, A. and Yoshida, A. (1995) Gene 166, 303-306]. We have examined RALDH expression in the stomach and small intestine before and during postnatal development and in vitamin A deficiency by assaying for mRNA levels and protein as well as for enzyme activity. In -2 day fetuses, RALDH expression was high in the small intestine, whereas RALDH protein was not detectable in the stomach. However, expression of RALDH was seen in the stomach after birth, and gradually increased with age and reached the highest level at postnatal day 42. In the intestine, RALDH expression decreased postnatally. Vitamin A deficiency up-regulated RALDH expression in the stomach and small intestine, and administration of retinoids down-regulated the RALDH expression in these tissues. These results show the differential expression of RALDH in the stomach and small intestine during postnatal development, and that vitamin A status regulates the expression of RALDH gene in these tissues.

Estrogen Regulation of Fetal Adrenal Cortical Zone-Specific Development in the Nonhuman Primate Impacts Adrenal Production of Androgen and Cortisol and Response to ACTH in Females in Adulthood

PubMed Central

Maniu, Adina; Aberdeen, Graham; Lynch, Terrie J.; Albrecht, Eugene D.

2016-01-01

We showed that the volume of the fetal zone of the fetal adrenal gland and serum dehydroepiandrosterone sulfate (DHAS) levels at term were increased in baboons in which estradiol levels were suppressed by treatment with aromatase inhibitor 4,4-[1,2,3-triazol-1yl-methylene] bis-benzonitrite (letrozole). The fetal zone remodels postnatally into the reticular zone and DHAS production, and serum levels decline with age. Therefore, we determined whether the trajectory of reticular zone DHAS secretion and response to ACTH were altered in offspring deprived of estrogen in utero. Female offspring were delivered to baboons untreated or treated daily throughout the second half of gestation with letrozole (estradiol reduced >95%) or letrozole plus estradiol and cortisol and DHAS determined in blood samples obtained bimonthly between 4 and 125 months and after iv bolus of ACTH. The slope/rate of decline in serum DHAS with advancing age was greater (P < .01) in letrozole-treated (−0.54 ± 0.005) than untreated (−0.32 ± 0.003) baboons and partially restored by letrozole-estradiol (−0.43 ± 0.004). Serum cortisol was similar and relatively constant in all offspring. Moreover, in letrozole-treated offspring, serum DHAS at 61–66, 67–95, and 96–125 months were lower (P < .05), and cortisol to DHAS ratio was greater (P < .05) than in untreated offspring. ACTH at high level increased cortisol and DHAS in untreated baboons and cortisol but not DHAS in letrozole-treated offspring. We propose that postnatal development of the primate adrenal cortex, including the decline in reticular zone DHAS production, response to ACTH and maintenance of cortisol to DHAS ratio with advancing age is modulated by exposure of the fetal adrenal to estradiol. PMID:26990066

A WEB-BASED SURVEY OF MOTHER-INFANT BOND, ATTACHMENT EXPERIENCES, AND METACOGNITION IN POSTTRAUMATIC STRESS FOLLOWING CHILDBIRTH.

PubMed

Williams, Charlotte; Patricia Taylor, Emily; Schwannauer, Matthias

2016-05-01

Postnatal depression is linked to adverse outcomes for parent and child, with metacognition and parenting experiences key variables in the development and maintenance of depression. The attachment between mother and infant is especially vulnerable to the effects of untreated postnatal depression. Despite high levels of reported postnatal stress symptoms, less attention has been given the relationship between attachment, metacognition, and postnatal traumatic symptoms in the context of birth trauma. This study tested several hypotheses regarding the relationships between recalled parenting experiences, metacognition, postnatal symptoms of posttraumatic stress disorder and depression and perceptions of the mother-infant bond, confirming and extending upon metacognitive and mentalization theories. A Web-based, cross-sectional, self-report questionnaire design was employed in an analog sample of new mothers. Participants were 502 women recruited via open-access Web sites associated with birth organizations. Structural equation modeling was employed for the principal analysis. Metacognition fully mediated the relationship between recalled parenting experiences and postnatal psychological outcomes. Posttraumatic stress was indirectly associated with maternal perceptions of the bond, with this relationship mediated by depression. Metacognition may have a key role in postnatal psychological distress. Where postnatal depression or traumatic birth experiences are identified, screening for posttraumatic stress is strongly indicated. © 2016 Michigan Association for Infant Mental Health.

The extended trajectory of hippocampal development: Implications for early memory development and disorder.

PubMed

Gómez, Rebecca L; Edgin, Jamie O

2016-04-01

Hippocampus has an extended developmental trajectory, with refinements occurring in the trisynaptic circuit until adolescence. While structural change should suggest a protracted course in behavior, some studies find evidence of precocious hippocampal development in the first postnatal year and continuity in memory processes beyond. However, a number of memory functions, including binding and relational inference, can be cortically supported. Evidence from the animal literature suggests that tasks often associated with hippocampus (visual paired comparison, binding of a visuomotor response) can be mediated by structures external to hippocampus. Thus, a complete examination of memory development will have to rule out cortex as a source of early memory competency. We propose that early memory must show properties associated with full function of the trisynaptic circuit to reflect "adult-like" memory function, mainly (1) rapid encoding of contextual details of overlapping patterns, and (2) retention of these details over sleep-dependent delays. A wealth of evidence suggests that these functions are not apparent until 18-24 months, with behavioral discontinuities reflecting shifts in the neural structures subserving memory beginning approximately at this point in development. We discuss the implications of these observations for theories of memory and for identifying and measuring memory function in populations with typical and atypical hippocampal function. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

Recurrent hypoinsulinemic hyperglycemia in neonatal rats increases PARP-1 and NF-κB expression and leads to microglial activation in the cerebral cortex.

PubMed

Gisslen, Tate; Ennis, Kathleen; Bhandari, Vineet; Rao, Raghavendra

2015-11-01

Hyperglycemia is a common metabolic problem in extremely low-birth-weight preterm infants. Neonatal hyperglycemia is associated with increased mortality and brain injury. Glucose-mediated oxidative injury may be responsible. Poly(ADP-ribose) polymerase-1 (PARP-1) is a nuclear enzyme involved in DNA repair and cell survival. However, PARP-1 overactivation leads to cell death. NF-κB is coactivated with PARP-1 and regulates microglial activation. The effects of recurrent hyperglycemia on PARP-1/NF-κB expression and microglial activation are not well understood. Rat pups were subjected to recurrent hypoinsulinemic hyperglycemia of 2 h duration twice daily from postnatal (P) day 3-P12 and killed on P13. mRNA and protein expression of PARP-1/NF-κB and their downstream effectors were determined in the cerebral cortex. Microgliosis was determined using CD11 immunohistochemistry. Recurrent hyperglycemia increased PARP-1 expression confined to the nucleus and without causing PARP-1 overactivation and cell death. NF-κB mRNA expression was increased, while IκB mRNA expression was decreased. inducible nitric oxide synthase (iNOS), endothelial nitric oxide synthase (eNOS), and neuronal nitric oxide synthase (nNOS) mRNA expressions were decreased. Hyperglycemia significantly increased the number of microglia. Recurrent hyperglycemia in neonatal rats is associated with upregulation of PARP-1 and NF-κB expression and subsequent microgliosis but not neuronal cell death in the cerebral cortex.

A structure-based extracellular matrix expansion mechanism of fibrous tissue growth.

PubMed

Kalson, Nicholas S; Lu, Yinhui; Taylor, Susan H; Starborg, Tobias; Holmes, David F; Kadler, Karl E

2015-05-20

Embryonic growth occurs predominately by an increase in cell number; little is known about growth mechanisms later in development when fibrous tissues account for the bulk of adult vertebrate mass. We present a model for fibrous tissue growth based on 3D-electron microscopy of mouse tendon. We show that the number of collagen fibrils increases during embryonic development and then remains constant during postnatal growth. Embryonic growth was explained predominately by increases in fibril number and length. Postnatal growth arose predominately from increases in fibril length and diameter. A helical crimp structure was established in embryogenesis, and persisted postnatally. The data support a model where the shape and size of tendon is determined by the number and position of embryonic fibroblasts. The collagen fibrils that these cells synthesise provide a template for postnatal growth by structure-based matrix expansion. The model has important implications for growth of other fibrous tissues and fibrosis.

Interactions of ( sup 3 H)amphetamine with rat brain synaptosomes. I. Saturable sequestration

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zaczek, R.; Culp, S.; Goldberg, H.

1991-05-01

Previous studies have identified a saturable site of d-({sup 3}H)amphetamine sequestration (AMSEQ) in rat brain synaptosomes. The present study characterized AMSEQ with respect to its subcellular, neuronal and regional distributions, ontogenetic development, pharmacological specificity and factors required for its maintenance. Although AMSEQ was reduced when assays were performed in Krebs' buffer incubated at 37{degree}C as compared to assays performed in isotonic Tris-sucrose buffer incubated at room temperature, the pharmacological profiles of AMSEQ were virtually identical under both conditions. AMSEQ was negligible in tissues outside the central nervous system, enriched in synaptosomes and partially reduced by striatal kainic acid lesion, indicatingmore » neuronal localization. The distribution of AMSEQ in the central nervous system was heterogenous. Highest levels were present in hypothalamus with progressively lower levels noted in parietal cortex, frontal cortex, striatum, thalamus, hippocampus, midbrain, cerebellum, pons-medulla and spinal cord. With regard to its ontogeny, AMSEQ increased early in neonatal life, reaching adult levels by postnatal day 14. Although the effects of amphetamine to abolish the transynaptosomal pH gradient suggest a possible role for this gradient in the maintenance of AMSEQ, the pharmacological profile of AMSEQ indicates that other factors are involved. An interaction with an intrasynaptosomal acid, such as N-acetylaspartate, may account for AMSEQ maintenance. AMSEQ did not possess a stereospecific preference for either d-(IC50 = 177 microM) or I-amphetamine (IC50 = 173 microM). However, the pharmacological profile of AMSEQ indicated structural specificity with antidepressants being relatively potent inhibitors. (Abstract Truncated)« less

Early Social Isolation Stress and Perinatal NMDA Receptor Antagonist Treatment Induce Changes in the Structure and Neurochemistry of Inhibitory Neurons of the Adult Amygdala and Prefrontal Cortex

PubMed Central

Bellés, María; Gilabert-Juan, Javier; Llorens, José Vicente; Bueno-Fernández, Clara; Ripoll-Martínez, Beatriz; Curto, Yasmina; Sebastiá-Ortega, Noelia; Sanjuan, Julio

2017-01-01

Abstract The exposure to aversive experiences during early life influences brain development and leads to altered behavior. Moreover, the combination of these experiences with subtle alterations in neurodevelopment may contribute to the emergence of psychiatric disorders, such as schizophrenia. Recent hypotheses suggest that imbalances between excitatory and inhibitory (E/I) neurotransmission, especially in the prefrontal cortex and the amygdala, may underlie their etiopathology. In order to understand better the neurobiological bases of these alterations, we studied the impact of altered neurodevelopment and chronic early-life stress on these two brain regions. Transgenic mice displaying fluorescent excitatory and inhibitory neurons, received a single injection of MK801 (NMDAR antagonist) or vehicle solution at postnatal day 7 and/or were socially isolated from the age of weaning until adulthood (3 months old). We found that anxiety-related behavior, brain volume, neuronal structure, and the expression of molecules related to plasticity and E/I neurotransmission in adult mice were importantly affected by early-life stress. Interestingly, many of these effects were potentiated when the stress paradigm was applied to mice perinatally injected with MK801 ("double-hit" model). These results clearly show the impact of early-life stress on the adult brain, especially on the structure and plasticity of inhibitory networks, and highlight the double-hit model as a valuable tool to study the contribution of early-life stress in the emergence of neurodevelopmental psychiatric disorders, such as schizophrenia. PMID:28466069

Rapid regulation of brain-derived neurotrophic factor mRNA within eye-specific circuits during ocular dominance column formation.

PubMed

Lein, E S; Shatz, C J

2000-02-15

The neurotrophin brain-derived neurotrophic factor (BDNF) has emerged as a candidate retrograde signaling molecule for geniculocortical axons during the formation of ocular dominance columns. Here we examined whether neuronal activity can regulate BDNF mRNA in eye-specific circuits in the developing cat visual system. Dark-rearing throughout the critical period for ocular dominance column formation decreases levels of BDNF mRNA within primary visual cortex, whereas short-term (2 d) binocular blockade of retinal activity with tetrodotoxin (TTX) downregulates BDNF mRNA within the lateral geniculate nucleus (LGN) and visual cortical areas. Brief (6 hr to 2 d) monocular TTX blockade during the critical period and also in adulthood causes downregulation in appropriate eye-specific laminae in the LGN and ocular dominance columns within primary visual cortex. Monocular TTX blockade at postnatal day 23 also downregulates BDNF mRNA in a periodic fashion, consistent with recent observations that ocular dominance columns can be detected at these early ages by physiological methods. In contrast, 10 d monocular TTX during the critical period does not cause a lasting decrease in BDNF mRNA expression in columns pertaining to the treated eye, consistent with the nearly complete shift in physiological response properties of cortical neurons in favor of the unmanipulated eye known to result from long-term monocular deprivation. These observations demonstrate that BDNF mRNA levels can provide an accurate "molecular readout" of the activity levels of cortical neurons and are consistent with a highly local action of BDNF in strengthening and maintaining active synapses during ocular dominance column formation.

Identification of long non-coding RNA and mRNA expression in βΒ2-crystallin knockout mice.

PubMed

Jia, Yin; Xiong, Kang; Ren, Han-Xiao; Li, Wen-Jie

2018-05-01

βΒ2-crystallin (CRYBB2) is expressed at an increased level in the postnatal lens cortex and is associated with cataracts. Improved understanding of the underlying biology of cataracts is likely to be critical for the development of early detection strategies and new therapeutics. The present study aimed to identify long non-coding RNAs (lncRNAs) and mRNAs associated with CRYBB2 knockdown (KO)-induced cataracts. RNAs from 3 non-treated mice and 3 CRYBB2 KO mice were analyzed using the Affymetrix GeneChip Mouse Gene 2.0 ST array. A total of 149 lncRNAs and 803 mRNAs were identified to have upregulated expression, including Snora73b, Klk1b22 and Rnu3a, while the expression levels of 180 lncRNAs and 732 mRNAs were downregulated in CRYBB2 KO mice, including Snord82, Snhg9 and Foxn3. This lncRNA and mRNA expression profile of mice with CRYBB2 KO provides a basis for studying the genetic mechanisms of cataract progression.

Combined small-molecule inhibition accelerates the derivation of functional, early-born, cortical neurons from human pluripotent stem cells

PubMed Central

Qi, Yuchen; Zhang, Xin-Jun; Renier, Nicolas; Wu, Zhuhao; Atkin, Talia; Sun, Ziyi; Ozair, M. Zeeshan; Tchieu, Jason; Zimmer, Bastian; Fattahi, Faranak; Ganat, Yosif; Azevedo, Ricardo; Zeltner, Nadja; Brivanlou, Ali H.; Karayiorgou, Maria; Gogos, Joseph; Tomishima, Mark; Tessier-Lavigne, Marc; Shi, Song-Hai; Studer, Lorenz

2017-01-01

Considerable progress has been made in converting human pluripotent stem cells (hPSCs) into functional neurons. However, the protracted timing of human neuron specification and functional maturation remains a key challenge that hampers the routine application of hPSC-derived lineages in disease modeling and regenerative medicine. Using a combinatorial small-molecule screen, we previously identified conditions for the rapid differentiation of hPSCs into peripheral sensory neurons. Here we generalize the approach to central nervous system (CNS) fates by developing a small-molecule approach for accelerated induction of early-born cortical neurons. Combinatorial application of 6 pathway inhibitors induces post-mitotic cortical neurons with functional electrophysiological properties by day 16 of differentiation, in the absence of glial cell co-culture. The resulting neurons, transplanted at 8 days of differentiation into the postnatal mouse cortex, are functional and establish long-distance projections, as shown using iDISCO whole brain imaging. Accelerated differentiation into cortical neuron fates should facilitate hPSC-based strategies for disease modeling and cell therapy in CNS disorders. PMID:28112759

Theta Oscillations During Active Sleep Synchronize The Developing Rubro-Hippocampal Sensorimotor Network

PubMed Central

Rio-Bermudez, Carlos Del; Kim, Jangjin; Sokoloff, Greta; Blumberg, Mark S.

2017-01-01

Summary Neuronal oscillations comprise a fundamental mechanism by which distant neural structures establish and express functional connectivity. Long-range functional connectivity between the hippocampus and other forebrain structures is enabled by theta oscillations. Here we show for the first time that the infant rat red nucleus (RN)—a brainstem sensorimotor structure— exhibits theta (4-7 Hz) oscillations restricted primarily to periods of active (REM) sleep. At postnatal day (P) 8, theta is expressed as brief bursts immediately following myoclonic twitches; by P12, theta oscillations are expressed continuously across bouts of active sleep. Simultaneous recordings from the hippocampus and RN at P12 show that theta oscillations in both structures are coherent, co-modulated, and mutually interactive during active sleep. Critically, at P12, inactivation of the medial septum eliminates theta in both structures. The developmental emergence of theta-dependent functional coupling between the hippocampus and RN parallels that between the hippocampus and prefrontal cortex. Accordingly, disruptions in the early expression of theta could underlie the cognitive and sensorimotor deficits associated with neurodevelopmental disorders such as autism and schizophrenia. PMID:28479324

Pathological effects of in utero methylmercury exposure on the cerebellum of the golden hamster: early effects upon the neonatal cerebellar cortex-Part I

DOE Office of Scientific and Technical Information (OSTI.GOV)

Reuhl, K.R.; Chang, L.W.; Townsend, J.W.

1981-12-01

Pregnant golden hamsters (Mesocricetus auratus) were given either a single dose of 10 mg methylmercury/kg on gestational day 10 or daily doses of 2 mg/kg on gestational days 10-15. Cerebella of experimental and control offspring were examined by light and electron microscopy during the first month of postnatal life. Degenerative changes, characterized by accumulations of lysosomes and areas of floccular cytoplasmic degradation, were frequently observed in neuroblasts of the external granular layer (EGL) as well as in more differentiated neural elements in the molecular and internal granular layers. Pyknotic nuclei were seen singly and in groups throughout the EGL ofmore » treated animals. Developing dendrites appeared particularly sensitive to methylmercury. Affected dendrites were swollen and packed with degenerating cytoplasmic material. Astrocytes and perivascular macrophages also contained large aggregates of irregular electron-opague debris, lysosomes, and large lipid droplets. Pathological alterations in the cerebellum were most pronounced during the first 15 days of postpartum life.« less

Neurobehavioral Development of Common Marmoset Monkeys

PubMed Central

Schultz-Darken, Nancy; Braun, Katarina M.; Emborg, Marina E.

2016-01-01

Common marmoset (Callithrix jacchus) monkeys are a resource for biomedical research and their use is predicted to increase due to the suitability of this species for transgenic approaches. Identification of abnormal neurodevelopment due to genetic modification relies upon the comparison with validated patterns of normal behavior defined by unbiased methods. As scientists unfamiliar with nonhuman primate development are interested to apply genomic editing techniques in marmosets, it would be beneficial to the field that the investigators use validated methods of postnatal evaluation that are age and species appropriate. This review aims to analyze current available data on marmoset physical and behavioral postnatal development, describe the methods used and discuss next steps to better understand and evaluate marmoset normal and abnormal postnatal neurodevelopment PMID:26502294

Alterations of amino acids and monoamine metabolism in male Fmr1 knockout mice: a putative animal model of the human fragile X mental retardation syndrome.

PubMed

Gruss, M; Braun, K

2001-01-01

The Fragile X syndrome, a common form of mental retardation in humans, is caused by silencing the fragile X mental retardation (FMR1) gene leading to the absence of the encoded fragile X mental retardation protein 1 (FMRP). We describe morphological and behavioral abnormalities for both affected humans and Fmr1 knockout mice, a putative animal model for the human Fragile X syndrome. The aim of the present study was to identify possible neurochemical abnormalities in Fmr1 knockout mice, with particular focus on neurotransmission. Significant region-specific differences of basal neurotransmitter and metabolite levels were found between wildtype and Fmr1 knockout animals, predominantly in juveniles (post-natal days 28 to 31). Adults (postnatal days 209 to 221) showed only few abnormalities as compared with the wildtype. In juvenile knockout mice, aspartate and taurine were especially increased in cortical regions, striatum, hippocampus, cerebellum, and brainstem. In addition, juveniles showed an altered balance between excitatory and inhibitory amino acids in the caudal cortex, hippocampus, and brainstem. We detected very few differences in monoamine turnover in both age stages. The results presented here provide the first evidence that lack of FMRP expression in FMRP knockout mice is accompanied by age-dependent, region-specific alterations in neurotransmission.

Germline stem cells and neo-oogenesis in the adult human ovary.

PubMed

Liu, Yifei; Wu, Chao; Lyu, Qifeng; Yang, Dongzi; Albertini, David F; Keefe, David L; Liu, Lin

2007-06-01

It remains unclear whether neo-oogenesis occurs in postnatal ovaries of mammals, based on studies in mice. We thought to test whether adult human ovaries contain germline stem cells (GSCs) and undergo neo-oogenesis. Rather than using genetic manipulation which is unethical in humans, we took the approach of analyzing the expression of meiotic marker genes and genes for germ cell proliferation, which are required for neo-oogenesis, in adult human ovaries covering an age range from 28 to 53 years old, compared to testis and fetal ovaries served as positive controls. We show that active meiosis, neo-oogenesis and GSCs are unlikely to exist in normal, adult, human ovaries. No early meiotic-specific or oogenesis-associated mRNAs for SPO11, PRDM9, SCP1, TERT and NOBOX were detectable in adult human ovaries using RT-PCR, compared to fetal ovary and adult testis controls. These findings are further corroborated by the absence of early meiocytes and proliferating germ cells in adult human ovarian cortex probed with markers for meiosis (SCP3), oogonium (OCT3/4, c-KIT), and cell cycle progression (Ki-67, PCNA), in contrast to fetal ovary controls. If postnatal oogenesis is confirmed in mice, then this species would represent an exception to the rule that neo-oogenesis does not occur in adults.

Cortical Structure Alterations and Social Behavior Impairment in p50-Deficient Mice.

PubMed

Bonini, Sara Anna; Mastinu, Andrea; Maccarinelli, Giuseppina; Mitola, Stefania; Premoli, Marika; La Rosa, Luca Rosario; Ferrari-Toninelli, Giulia; Grilli, Mariagrazia; Memo, Maurizio

2016-06-01

Alterations in genes that regulate neurodevelopment can lead to cortical malformations, resulting in malfunction during postnatal life. The NF-κB pathway has a key role during neurodevelopment by regulating the maintenance of the neural progenitor cell pool and inhibiting neuronal differentiation. In this study, we evaluated whether mice lacking the NF-κB p50 subunit (KO) present alterations in cortical structure and associated behavioral impairment. We found that, compared with wild type (WT), KO mice at postnatal day 2 present an increase in radial glial cells, an increase in Reelin protein expression levels, in addition to an increase of specific layer thickness. Moreover, adult KO mice display abnormal columnar organization in the somatosensory cortex, a specific decrease in somatostatin- and parvalbumin-expressing interneurons, altered neurite orientation, and a decrease in Synapsin I protein levels. Concerning behavior, KO mice, in addition to an increase in locomotor and exploratory activity, display impairment in social behaviors, with a reduction in social interaction. Finally, we found that risperidone treatment decreased hyperactivity of KO mice, but had no effect on defective social interaction. Altogether, these data add complexity to a growing body of data, suggesting a link between dysregulation of the NF-κB pathway and neurodevelopmental disorders pathogenesis. © The Author 2016. Published by Oxford University Press.

Deletion of neurturin impairs development of cholinergic nerves and heart rate control in postnatal mouse hearts.

PubMed

Downs, Anthony M; Jalloh, Hawa B; Prater, Kayla J; Fregoso, Santiago P; Bond, Cherie E; Hampton, Thomas G; Hoover, Donald B

2016-05-01

The neurotrophic factor neurturin is required for normal cholinergic innervation of adult mouse heart and bradycardic responses to vagal stimulation. Our goals were to determine effects of neurturin deletion on development of cardiac chronotropic and dromotropic functions, vagal baroreflex response, and cholinergic nerve density in nodal regions of postnatal mice. Experiments were performed on postnatal C57BL/6 wild-type (WT) and neurturin knockout (KO) mice. Serial electrocardiograms were recorded noninvasively from conscious pups using an ECGenie apparatus. Mice were treated with atenolol to evaluate and block sympathetic effects on heart rate (HR) and phenylephrine (PE) to stimulate the baroreflex. Immunohistochemistry was used to label cholinergic nerves in paraffin sections. WT and KO mice showed similar age-dependent increases in HR and decreases in PR interval between postnatal days (P) 2.5 and 21. Treatment with atenolol reduced HR significantly in WT and KO pups at P7.5. PE caused a reflex bradycardia that was significantly smaller in KO pups. Cholinergic nerve density was significantly less in nodal regions of P7.5 KO mice. We conclude that cholinergic nerves have minimal influence on developmental changes in HR and PR, QRS, and QTc intervals in mouse pups. However, cholinergic nerves mediate reflex bradycardia by 1 week postnatally. Deletion of neurturin impairs cholinergic innervation of the heart and the vagal efferent component of the baroreflex early during postnatal development. © 2016 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of the American Physiological Society and The Physiological Society.

MEAL PARAMETERS AND VAGAL GASTROINTESTINAL AFFERENTS IN MICE THAT EXPERIENCED EARLY POSTNATAL OVERNUTRITION

PubMed Central

Biddinger, Jessica E.; Fox, Edward A.

2010-01-01

Early postnatal overnutrition results in a predisposition to develop obesity due in part to hypothalamic and sympathetic dysfunction. Potential involvement of another major regulatory system component - the vagus nerve - has not been examined. Moreover, feeding disturbances have rarely been investigated prior to development of obesity when confounds due to obesity are minimized. To examine these issues, litters were culled on the day of birth to create small litters (SL; overnutrition), or normal-size litters (NL; normal nutrition). Body weight, fat pad weight, meal patterns, and vagal sensory duodenal innervation were compared between SL and NL adult mice prior to development of obesity. Meal patterns were studied 18 hour/day for 3 weeks using a balanced diet. Then vagal mechanoreceptors were labeled using anterograde transport of wheatgerm agglutinin-horseradish peroxidase injected into the nodose ganglion and their density and morphology were examined. Between postnatal day 1 and weaning, body weight of SL mice was greater than for NL mice. By young adulthood it was similar in both groups, whereas SL fat pad weight was greater in males, suggesting postnatal overnutrition produced a predisposition to obesity. SL mice exhibited increased food intake, decreased satiety ratio, and increased first meal rate (following mild food deprivation) compared to NL mice, suggesting postnatal overnutrition disrupted satiety. The density and structure of intestinal IGLEs appeared similar in SL and NL mice. Thus, although a vagal role cannot be excluded, our meal parameter and anatomical findings provided no evidence for significant postnatal overnutrition effects on vagal gastrointestinal afferents. PMID:20403369

Meal parameters and vagal gastrointestinal afferents in mice that experienced early postnatal overnutrition.

PubMed

Biddinger, Jessica E; Fox, Edward A

2010-08-04

Early postnatal overnutrition results in a predisposition to develop obesity due in part to hypothalamic and sympathetic dysfunction. Potential involvement of another major regulatory system component--the vagus nerve--has not been examined. Moreover, feeding disturbances have rarely been investigated prior to development of obesity when confounds due to obesity are minimized. To examine these issues, litters were culled on the day of birth to create small litters (SL; overnutrition), or normal size litters (NL; normal nutrition). Body weight, fat pad weight, meal patterns, and vagal sensory duodenal innervation were compared between SL and NL adult mice prior to development of obesity. Meal patterns were studied 18 h/day for 3 weeks using a balanced diet. Then vagal mechanoreceptors were labeled using anterograde transport of wheatgerm agglutinin-horseradish peroxidase injected into the nodose ganglion and their density and morphology were examined. Between postnatal day 1 and weaning, body weight of SL mice was greater than for NL mice. By young adulthood it was similar in both groups, whereas SL fat pad weight was greater in males, suggesting postnatal overnutrition produced a predisposition to obesity. SL mice exhibited increased food intake, decreased satiety ratio, and increased first meal rate (following mild food deprivation) compared to NL mice, suggesting postnatal overnutrition disrupted satiety. The density and structure of intestinal IGLEs appeared similar in SL and NL mice. Thus, although a vagal role cannot be excluded, our meal parameter and anatomical findings provided no evidence for significant postnatal overnutrition effects on vagal gastrointestinal afferents. Copyright 2010 Elsevier Inc. All rights reserved.

Developmental regulation of inhibitory synaptic currents in the dorsal motor nucleus of the vagus in the rat

PubMed Central

Anselmi, Laura; Travagli, R. Alberto

2016-01-01

Prior immunohistochemical studies have demonstrated that at early postnatal time points, central vagal neurons receive both glycinergic and GABAergic inhibitory inputs. Functional studies have demonstrated, however, that adult vagal efferent motoneurons receive only inhibitory GABAergic synaptic inputs, suggesting loss of glycinergic inhibitory neurotransmission during postnatal development. The purpose of the present study was to test the hypothesis that the loss of glycinergic inhibitory synapses occurs in the immediate postnatal period. Whole cell patch-clamp recordings were made from dorsal motor nucleus of the vagus (DMV) neurons from postnatal days 1–30, and the effects of the GABAA receptor antagonist bicuculline (1–10 μM) and the glycine receptor antagonist strychnine (1 μM) on miniature inhibitory postsynaptic current (mIPSC) properties were examined. While the baseline frequency of mIPSCs was not altered by maturation, perfusion with bicuculline either abolished mIPSCs altogether or decreased mIPSC frequency and decay constant in the majority of neurons at all time points. In contrast, while strychnine had no effect on mIPSC frequency, its actions to increase current decay time declined during postnatal maturation. These data suggest that in early postnatal development, DMV neurons receive both GABAergic and glycinergic synaptic inputs. Glycinergic neurotransmission appears to decline by the second postnatal week, and adult neurons receive principally GABAergic inhibitory inputs. Disruption of this developmental switch from GABA-glycine to purely GABAergic transmission in response to early life events may, therefore, lead to adverse consequences in vagal efferent control of visceral functions. PMID:27440241

Laminar Differences in Dendritic Structure of Pyramidal Neurons in the Juvenile Rat Somatosensory Cortex.

PubMed

Rojo, Concepción; Leguey, Ignacio; Kastanauskaite, Asta; Bielza, Concha; Larrañaga, Pedro; DeFelipe, Javier; Benavides-Piccione, Ruth

2016-06-01

Pyramidal cell structure varies between different cortical areas and species, indicating that the cortical circuits that these cells participate in are likely to be characterized by different functional capabilities. Structural differences between cortical layers have been traditionally reported using either the Golgi method or intracellular labeling, but the structure of pyramidal cells has not previously been systematically analyzed across all cortical layers at a particular age. In the present study, we investigated the dendritic architecture of complete basal arbors of pyramidal neurons in layers II, III, IV, Va, Vb, and VI of the hindlimb somatosensory cortical region of postnatal day 14 rats. We found that the characteristics of basal dendritic morphologies are statistically different in each cortical layer. The variations in size and branching pattern that exist between pyramidal cells of different cortical layers probably reflect the particular functional properties that are characteristic of the cortical circuit in which they participate. This new set of complete basal dendritic arbors of 3D-reconstructed pyramidal cell morphologies across each cortical layer will provide new insights into interlaminar information processing in the cerebral cortex. © The Author 2016. Published by Oxford University Press.

Sensitivity Profile for Orientation Selectivity in the Visual Cortex of Goggle-Reared Mice

PubMed Central

Yoshida, Takamasa; Ozawa, Katsuya; Tanaka, Shigeru

2012-01-01

It has been widely accepted that ocular dominance in the responses of visual cortical neurons can change depending on visual experience in a postnatal period. However, experience-dependent plasticity for orientation selectivity, which is another important response property of visual cortical neurons, is not yet fully understood. To address this issue, using intrinsic signal imaging and two-photon calcium imaging we attempted to observe the alteration of orientation selectivity in the visual cortex of juvenile and adult mice reared with head-mounted goggles, through which animals can experience only the vertical orientation. After one week of goggle rearing, the density of neurons optimally responding to the exposed orientation increased, while that responding to unexposed orientations decreased. These changes can be interpreted as a reallocation of preferred orientations among visually responsive neurons. Our obtained sensitivity profile for orientation selectivity showed a marked peak at 5 weeks and sustained elevation at 12 weeks and later. These features indicate the existence of a critical period between 4 and 7 weeks and residual orientation plasticity in adult mice. The presence of a dip in the sensitivity profile at 10 weeks suggests that different mechanisms are involved in orientation plasticity in childhood and adulthood. PMID:22792390

Critical androgen-sensitive periods of rat penis and clitoris development

PubMed Central

Welsh, Michelle; MacLeod, David J; Walker, Marion; Smith, Lee B; Sharpe, Richard M

2010-01-01

Androgen control of penis development/growth is unclear. In rats, androgen action in a foetal ‘masculinisation programming window’ (MPW; e15.5–e18.5)’ predetermines penile length and hypospadias occurrence. This has implications for humans (e.g. micropenis). Our studies aimed to establish in rats when androgen action/administration affects development/growth of the penis and if deficits in MPW androgen action were rescuable postnatally. Thus, pregnant rats were treated with flutamide during the MPW ± postnatal testosterone propionate (TP) treatment. To assess penile growth responsiveness, rats were treated with TP in various time windows (late foetal, neonatal through early puberty, puberty onset, or combinations thereof). Phallus length, weight, and morphology, hypospadias and anogenital distance (AGD) were measured in mid-puberty (d25) or adulthood (d90) in males and females, plus serum testosterone in adult males. MPW flutamide exposure reduced adult penile length and induced hypospadias dose-dependently; this was not rescued by postnatal TP treatment. In normal rats, foetal (e14.5–e21.5) TP exposure did not affect male penis size but increased female clitoral size. In males, TP exposure from postnatal d1–24 or at puberty (d15–24), increased penile length at d25, but not ultimately in adulthood. Foetal + postnatal TP (e14–postnatal d24) increased penile size at d25 but reduced it at d90 (due to reduced endogenous testosterone). In females, this treatment caused the biggest increase in adult clitoral size but, unlike in males, phallus size was unaffected by TP during puberty (d15–24). Postnatal TP treatment advanced penile histology at d25 to more resemble adult histology. AGD strongly correlated with final penis length. It is concluded that adult penile size depends critically on androgen action during the MPW but subsequent growth depends on later androgen exposure. Foetal and/or postnatal TP exposure does not increase adult penile size above its ‘predetermined’ length though its growth towards this maximum is advanced by peripubertal TP treatment. PMID:19656234

Maternal Bonding through Pregnancy and Postnatal: Findings from an Australian Longitudinal Study.

PubMed

Rossen, Larissa; Hutchinson, Delyse; Wilson, Judy; Burns, Lucinda; Allsop, Steve; Elliott, Elizabeth J; Jacobs, Sue; Macdonald, Jacqui A; Olsson, Craig; Mattick, Richard P

2017-07-01

Background  Mother-infant bonding provides the foundation for secure attachment through the lifespan and organizes many facets of infant social-emotional development, including later parenting. Aims  To describe maternal bonding to offspring across the pregnancy and postnatal periods, and to examine a broad range of sociodemographic and psychosocial predictors of the maternal-offspring bond. Methods  Data were drawn from a sample of 372 pregnant women participating in an Australian population-based longitudinal study of postnatal health and development. Participants completed maternal bonding questionnaires at each trimester and 8 weeks postnatal. Data were collected on a range of sociodemographic and psychosocial factors. Results  Bonding increased significantly through pregnancy, in quality and intensity. Regression analyses indicated that stronger antenatal bonding at all time points (trimesters 1 through 3) predicted stronger postnatal bonding. Older maternal age, birth mother being born in a non-English speaking country, mother not working full time, being a first-time mother, breast-feeding problems, and baby's crying behavior all predicted poorer bonding at 8 weeks postpartum. Conclusion  These novel findings have important implications for pregnant women and their infant offspring, and for health care professionals working in perinatal services. Importantly, interventions to strengthen maternal-fetal bonding would be beneficial during pregnancy to enhance postnatal bonding and infant health outcomes. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Perinatal development of conjugative enzyme systems.

PubMed Central

Lucier, G W

1976-01-01

The problems and priorities involved in studying the role of conjugagive enzymes in developmental pharmacology are discussed and evaluated. The relative rates of UDP glucuronyltransferase and beta-glucuronidase were studied during perinatal development in hepatic and extrahepatic tissues to determine the net balance of glucuronidation or deglucuronidation at different developmental stages. In general, deglucuronidation predominated over glucuronidation in fetal tissues whereas the converse was evident in adults. 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD), an extremely toxic contaminant of some organochlorine compounds, was shown to be a potent inducer of some hepatic and extrahepatic drug-metabolizing enzymes. TCDD, administered during gestation, induced the postnatal activities of p-nitrophenol glucuronyltransferase and benzpyrene hydroxylase in rats. Foster mother experiments revealed that the postnatal induction was caused primarily by newborn exposure to TCDD in the mother's milk. Tissue distribution experiments with TCDD-14C confirmed these findings. Although TCDD induced non-steroid glucuronidation, no significant effects were evident on the postnatal development of steroid glucuronidation. The synthetic estrogen diethylstilbestrol (DES) is metabolized primarily by glucuronidation. The postnatal development of DES glucuronidation, like the steroid pathway, was not affected by gestational TCDD treatment. The fetal distribution of DES and DES-glucuronide, at different stages of development, correlated well with the perinatal development of steroid glucuronyltransferase activity. PMID:829487

Evaluation of gene expression profiles and pathways underlying postnatal development in mouse sclera.

PubMed

Lim, Wan'E; Kwan, Jia Lin; Goh, Liang Kee; Beuerman, Roger W; Barathi, Veluchamy A

2012-01-01

The aim of this study was to identify the genes and pathways underlying the growth of the mouse sclera during postnatal development. Total RNA was isolated from each of 30 single mouse sclera (n=30, 6 sclera each from 1-, 2-, 3-, 6-, and 8-week-old mice) and reverse-transcribed into cDNA using a T7-N(6) primer. The resulting cDNA was fragmented, labeled with biotin, and hybridized to a Mouse Gene 1.0 ST Array. ANOVA analysis was then performed using Partek Genomic Suite 6.5 beta and differentially expressed transcript clusters were filtered based on a selection criterion of ≥ 2 relative fold change at a false discovery rate of ≤ 5%. Genes identified as involved in the main biologic processes during postnatal scleral development were further confirmed using qPCR. A possible pathway that contributes to the postnatal development of the sclera was investigated using Ingenuity Pathway Analysis software. The hierarchical clustering of all time points showed that they did not cluster according to age. The highest number of differentially expressed transcript clusters was found when week 1 and week 2 old scleral tissues were compared. The peroxisome proliferator- activated receptor gamma coactivator 1-alpha (Ppargc1a) gene was found to be involved in the networks generated using Ingenuity Pathway Studio (IPA) from the differentially expressed transcript cluster lists of week 2 versus 1, week 3 versus 2, week 6 versus 3, and week 8 versus 6. The gene expression of Ppargc1a varied during scleral growth from week 1 to 2, week 2 to 3, week 3 to 6, and week 6 to 8 and was found to interact with a different set of genes at different scleral growth stages. Therefore, this indicated that Ppargc1a might play a role in scleral growth during postnatal weeks 1 to 8. Gene expression of eye diseases should be studied as early as postnatal weeks 1-2 to ensure that any changes in gene expression pattern during disease development are detected. In addition, we propose that Ppargc1a might play a role in regulating postnatal scleral development by interacting with a different set of genes at different scleral growth stages.

Evaluation of gene expression profiles and pathways underlying postnatal development in mouse sclera

PubMed Central

Lim, Wan’E.; Kwan, Jia Lin; Goh, Liang Kee; Beuerman, Roger W.

2012-01-01

Purpose The aim of this study was to identify the genes and pathways underlying the growth of the mouse sclera during postnatal development. Methods Total RNA was isolated from each of 30 single mouse sclera (n=30, 6 sclera each from 1-, 2-, 3-, 6-, and 8-week-old mice) and reverse-transcribed into cDNA using a T7-N6 primer. The resulting cDNA was fragmented, labeled with biotin, and hybridized to a Mouse Gene 1.0 ST Array. ANOVA analysis was then performed using Partek Genomic Suite 6.5 beta and differentially expressed transcript clusters were filtered based on a selection criterion of ≥2 relative fold change at a false discovery rate of ≤5%. Genes identified as involved in the main biologic processes during postnatal scleral development were further confirmed using qPCR. A possible pathway that contributes to the postnatal development of the sclera was investigated using Ingenuity Pathway Analysis software. Results The hierarchical clustering of all time points showed that they did not cluster according to age. The highest number of differentially expressed transcript clusters was found when week 1 and week 2 old scleral tissues were compared. The peroxisome proliferator- activated receptor gamma coactivator 1-alpha (Ppargc1a) gene was found to be involved in the networks generated using Ingenuity Pathway Studio (IPA) from the differentially expressed transcript cluster lists of week 2 versus 1, week 3 versus 2, week 6 versus 3, and week 8 versus 6. The gene expression of Ppargc1a varied during scleral growth from week 1 to 2, week 2 to 3, week 3 to 6, and week 6 to 8 and was found to interact with a different set of genes at different scleral growth stages. Therefore, this indicated that Ppargc1a might play a role in scleral growth during postnatal weeks 1 to 8. Conclusions Gene expression of eye diseases should be studied as early as postnatal weeks 1–2 to ensure that any changes in gene expression pattern during disease development are detected. In addition, we propose that Ppargc1a might play a role in regulating postnatal scleral development by interacting with a different set of genes at different scleral growth stages. PMID:22736935

Immunolocalization of NR1, NR2A, and PSD-95 in rat hippocampal subregions during postnatal development.

PubMed

Ling, Wei; Chang, Lirong; Song, Yizhi; Lu, Tao; Jiang, Yuhua; Li, Youxiang; Wu, Yan

2012-05-01

Although the expression of NMDARs and synaptic-associated proteins has been widely studied, the temporospatial distribution of NMDAR subunits and synaptic proteins in different hippocampal subregions during postnatal development still lacks detailed information, and the relationship between NR1 or NR2 subunits and PSD-95 family proteins is controversial. In this study, we used immunofluorescent staining to assess NR1 or NR2A and PSD-95 expressions and the relationship between them in CA1, CA3, and DG of rat hippocampus on postnatal (P) days: P0, P4, P7, P10, P14, P21, P28, P56. The results showed that from P0 to P56, NR1, NR2A, and PSD-95 expressions increased gradually, and the time points of their expression peak differed in CA1, CA3, and DG during postnatal development. Interestingly, although the expression of PSD-95 was positively correlated to both NR1 and NR2A, the NR1 and PSD-95 coexpressed puncta were greatest in CA3, while NR2A and PSD-95 coexpressed puncta were greatest in CA1, compared to other subregions. Surprisingly, at P21, among different strata of CA1, the area of highest expression of NR2A was dramatically changed from stratum pyramidale to stratum polymorphum and stratum moleculare, and returned to stratum pyramidale gradually on the later observed days again, indicating that P21 may be one critical timepoint during postnatal development in CA1. The specific temporospatial distribution pattern of NR1, NR2A, and PSD-95 might be related to the different physiological functions during postnatal development. Discovering the alteration of the relationship between PSD-95 and NMDAR subunits expression may be helpful for understanding mechanisms and therapy of neurodegenerative diseases. Copyright © 2011 Elsevier GmbH. All rights reserved.

A statewide review of postnatal care in private hospitals in Victoria, Australia.

PubMed

Rayner, Jo-Anne; McLachlan, Helen L; Forster, Della A; Peters, Louise; Yelland, Jane

2010-05-28

Concerns have been raised in Australia and internationally regarding the quality and effectiveness of hospital postnatal care, although Australian women receiving postnatal care in the private maternity sector rate their satisfaction with care more highly than women receiving public maternity care. In Victoria, Australia, two-thirds of women receive their maternity care in the public sector and the remainder in private health care sector. A statewide review of public hospital postnatal care in Victoria from the perspective of care providers found many barriers to care provision including the busyness of postnatal wards, inadequate staffing and priority being given to other episodes of care; however the study did not include private hospitals. The aim of this study was replicate the review in the private sector, to explore the structure and organisation of postnatal care in private hospitals and identify those aspects of care potentially impacting on women's experiences and maternal and infant care. This provides a more complete overview of the organisational structures and processes in postnatal care in all Victorian hospitals from the perspective of care providers. A mixed method design was used. A structured postal survey was sent to all Victorian private hospitals (n = 19) and key informant interviews were undertaken with selected clinical midwives, maternity unit managers and obstetricians (n = 11). Survey data were analysed using descriptive statistics and interview data analysed thematically. Private hospital care providers report that postnatal care is provided in very busy environments, and that meeting the aims of postnatal care (breastfeeding support, education of parents and facilitating rest and recovery for women following birth) was difficult in the context of increased acuity of postnatal care; prioritising of other areas over postnatal care; high midwife-to-woman ratios; and the number and frequency of visitors. These findings were similar to the public review. Organisational differences in postnatal care were found between the two sectors: private hospitals are more likely to have a separate postnatal care unit with single rooms and can accommodate partners' over-night; very few have a policy of infant rooming-in; and most have well-baby nurseries. Private hospitals are also more likely to employ staff other than midwives, have fewer core postnatal staff and have a greater dependence on casual and bank staff to provide postnatal care. There are similarities and differences in the organisation and provision of private postnatal care compared to postnatal care in public hospitals. Key differences between the two sectors relate to the organisational and aesthetic aspects of service provision rather than the delivery of postnatal care. The key messages emerging from both reviews is the need to review and monitor the adequacy of staffing levels and to develop alternative approaches to postnatal care to improve this episode of care for women and care providers alike. We also recommend further research to provide a greater evidence-base for postnatal care provision.

Tooth-bone morphogenesis during postnatal stages of mouse first molar development

PubMed Central

Lungová, Vlasta; Radlanski, Ralf J; Tucker, Abigail S; Renz, Herbert; Míšek, Ivan; Matalová, Eva

2011-01-01

The first mouse molar (M1) is the most common model for odontogenesis, with research particularly focused on prenatal development. However, the functional dentition forms postnatally, when the histogenesis and morphogenesis of the tooth is completed, the roots form and the tooth physically anchors into the jaw. In this work, M1 was studied from birth to eruption, assessing morphogenesis, proliferation and apoptosis, and correlating these with remodeling of the surrounding bony tissue. The M1 completed crown formation between postnatal (P) days 0–2, and the development of the tooth root was initiated at P4. From P2 until P12, cell proliferation in the dental epithelium reduced and shifted downward to the apical region of the forming root. In contrast, proliferation was maintained or increased in the mesenchymal cells of the dental follicle. At later stages, before tooth eruption (P20), cell proliferation suddenly ceased. This withdrawal from the cell cycle correlated with tooth mineralization and mesenchymal differentiation. Apoptosis was observed during all stages of M1 postnatal morphogenesis, playing a role in the removal of cells such as osteoblasts in the mandibular region and working together with osteoclasts to remodel the bone around the developing tooth. At more advanced developmental stages, apoptotic cells and bodies accumulated in the cell layers above the tooth cusps, in the path of eruption. Three-dimensional reconstruction of the developing postnatal tooth and bone indicates that the alveolar crypts form by resorption underneath the primordia, whereas the ridges form by active bone growth between the teeth and roots to form a functional complex. PMID:21418206

Intestinal microbiota influence the early postnatal development of the enteric nervous system.

PubMed

Collins, J; Borojevic, R; Verdu, E F; Huizinga, J D; Ratcliffe, E M

2014-01-01

Normal gastrointestinal function depends on an intact and coordinated enteric nervous system (ENS). While the ENS is formed during fetal life, plasticity persists in the postnatal period during which the gastrointestinal tract is colonized by bacteria. We tested the hypothesis that colonization of the bowel by intestinal microbiota influences the postnatal development of the ENS. The development of the ENS was studied in whole mount preparations of duodenum, jejunum, and ileum of specific pathogen-free (SPF), germ-free (GF), and altered Schaedler flora (ASF) NIH Swiss mice at postnatal day 3 (P3). The frequency and amplitude of circular muscle contractions were measured in intestinal segments using spatiotemporal mapping of video recorded spontaneous contractile activity with and without exposure to lidocaine and N-nitro-L-arginine (NOLA). Immunolabeling with antibodies to PGP9.5 revealed significant abnormalities in the myenteric plexi of GF jejunum and ileum, but not duodenum, characterized by a decrease in nerve density, a decrease in the number of neurons per ganglion, and an increase in the proportion of myenteric nitrergic neurons. Frequency of amplitude of muscle contractions were significantly decreased in the jejunum and ileum of GF mice and were unaffected by exposure to lidocaine, while NOLA enhanced contractile frequency in the GF jejunum and ileum. These findings suggest that early exposure to intestinal bacteria is essential for the postnatal development of the ENS in the mid to distal small intestine. Future studies are needed to investigate the mechanisms by which enteric microbiota interact with the developing ENS. © 2013 John Wiley & Sons Ltd.

The Role of Endothelin System in Renal Structure and Function during the Postnatal Development of the Rat Kidney.

PubMed

Albertoni Borghese, María F; Ortiz, María C; Balonga, Sabrina; Moreira Szokalo, Rocío; Majowicz, Mónica P

2016-01-01

Renal development in rodents, unlike in humans, continues during early postnatal period. We aimed to evaluate whether the pharmacological inhibition of Endothelin system during this period affects renal development, both at structural and functional level in male and female rats. Newborn rats were treated orally from postnatal day 1 to 20 with vehicle or bosentan (Actelion, 20 mg/kg/day), a dual endothelin receptor antagonist (ERA). The animals were divided in 4 groups: control males, control females, ERA males and ERA females. At day 21, we evaluated renal function, determined the glomerular number by a maceration method and by morphometric analysis and evaluated possible structural renal alterations by three methods: 〈alpha〉-Smooth muscle actin (α-SMA) immunohistochemistry, Masson's trichrome and Sirius red staining. The pharmacological inhibition of Endothelin system with a dual ERA during the early postnatal period of the rat did not leads to renal damage in the kidneys of male and female rats. However, ERA administration decreased the number of glomeruli, the juxtamedullary filtration surface area and the glomerular filtration rate and increased the proteinuria. These effects could predispose to hypertension or renal diseases in the adulthood. On the other hand, these effects were more pronounced in male rats, suggesting that there are sex differences that could be greater later in life. These results provide evidence that Endothelin has an important role in rat renal postnatal development. However these results do not imply that the same could happen in humans, since human renal development is complete at birth.

Early life exposure to environmental tobacco smoke alters immune response to asbestos via a shift in inflammatory phenotype resulting in increased disease development

PubMed Central

Brown, Traci A.; Holian, Andrij; Pinkerton, Kent E.; Lee, Joong Won; Cho, Yoon Hee

2016-01-01

Asbestos in combination with tobacco smoke exposure reportedly leads to more severe physiological consequences than asbestos alone; limited data also show an increased disease risk due to environmental tobacco smoke (ETS) exposure. Environmental influences during gestation and early lung development can result in physiological changes that alter risk for disease development throughout an individual’s lifetime. Therefore, maternal lifestyle may impact the ability of offspring to subsequently respond to environmental insults and alter overall disease susceptibility. In this study, we examined the effects of exposure to ETS in utero and during early postnatal development on asbestos-related inflammation and disease in adulthood. ETS exposure in utero appeared to shift inflammation towards a Th2 phenotype, via suppression of Th1 inflammatory cytokine production. This effect was further pronounced in mice exposed to ETS in utero and during early postnatal development. In utero ETS exposure led to increased collagen deposition, a marker of fibrotic disease, when the offspring was later exposed to asbestos, which was further increased with additional ETS exposure during early postnatal development. These data suggest that ETS exposure in utero alters the immune responses and leads to greater disease development after asbestos exposure, which is further exacerbated when exposure to ETS continues during early postnatal development. PMID:27138493

Maturation of Cerebellar Purkinje Cell Population Activity during Postnatal Refinement of Climbing Fiber Network.

PubMed

Good, Jean-Marc; Mahoney, Michael; Miyazaki, Taisuke; Tanaka, Kenji F; Sakimura, Kenji; Watanabe, Masahiko; Kitamura, Kazuo; Kano, Masanobu

2017-11-21

Neural circuits undergo massive refinements during postnatal development. In the developing cerebellum, the climbing fiber (CF) to Purkinje cell (PC) network is drastically reshaped by eliminating early-formed redundant CF to PC synapses. To investigate the impact of CF network refinement on PC population activity during postnatal development, we monitored spontaneous CF responses in neighboring PCs and the activity of populations of nearby CF terminals using in vivo two-photon calcium imaging. Population activity is highly synchronized in newborn mice, and the degree of synchrony gradually declines during the first postnatal week in PCs and, to a lesser extent, in CF terminals. Knockout mice lacking P/Q-type voltage-gated calcium channel or glutamate receptor δ2, in which CF network refinement is severely impaired, exhibit an abnormally high level of synchrony in PC population activity. These results suggest that CF network refinement is a structural basis for developmental desynchronization and maturation of PC population activity. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.

Maternal Pre- and Postnatal Mental Health Trajectories and Child Mental Health and Development: Prospective Study in a Normative and Formerly Infertile Sample

ERIC Educational Resources Information Center

Vanska, Mervi; Punamaki, Raija-Leena; Tolvanen, Asko; Lindblom, Jallu; Flykt, Marjo; Unkila-Kallio, Leila; Tiitinen, Aila; Repokari, Leena; Sinkkonen, Jari; Tulppala, Maija

2011-01-01

Pregnancy and early motherhood involve uncertainty and change, which can evoke mental health problems. We identified maternal mental health trajectories in pre- and postnatal period, and examined their association with later child mental health and development. Finnish mothers reported psychological distress (General Health Questionnaire [GHQ-36])…

Mitochondrial dysfunction in alveolar and white matter developmental failure in premature infants

PubMed Central

Ten, Vadim S.

2017-01-01

At birth, some organs in premature infants are not developed enough to meet challenges of the extra-uterine life. Although growth and maturation continues after premature birth, postnatal organ development may become sluggish or even arrested, leading to organ dysfunction. There is no clear mechanistic concept of this postnatal organ developmental failure in premature neonates. This review introduces a concept-forming hypothesis: Mitochondrial bioenergetic dysfunction is a fundamental mechanism of organs maturation failure in premature infants. Data collected in support of this hypothesis are relevant to two major diseases of prematurity: white matter injury and broncho-pulmonary dysplasia. In these diseases, totally different clinical manifestations are defined by the same biological process, developmental failure of the main functional units—alveoli in the lungs and axonal myelination in the brain. Although molecular pathways regulating alveolar and white matter maturation differ, proper bioenergetic support of growth and maturation remains critical biological requirement for any actively developing organ. Literature analysis suggests that successful postnatal pulmonary and white matter development highly depends on mitochondrial function which can be inhibited by sublethal postnatal stress. In premature infants, sublethal stress results mostly in organ maturation failure without excessive cellular demise. PMID:27901512

Mitochondrial dysfunction in alveolar and white matter developmental failure in premature infants.

PubMed

Ten, Vadim S

2017-02-01

At birth, some organs in premature infants are not developed enough to meet challenges of the extra-uterine life. Although growth and maturation continues after premature birth, postnatal organ development may become sluggish or even arrested, leading to organ dysfunction. There is no clear mechanistic concept of this postnatal organ developmental failure in premature neonates. This review introduces a concept-forming hypothesis: Mitochondrial bioenergetic dysfunction is a fundamental mechanism of organs maturation failure in premature infants. Data collected in support of this hypothesis are relevant to two major diseases of prematurity: white matter injury and broncho-pulmonary dysplasia. In these diseases, totally different clinical manifestations are defined by the same biological process, developmental failure of the main functional units-alveoli in the lungs and axonal myelination in the brain. Although molecular pathways regulating alveolar and white matter maturation differ, proper bioenergetic support of growth and maturation remains critical biological requirement for any actively developing organ. Literature analysis suggests that successful postnatal pulmonary and white matter development highly depends on mitochondrial function which can be inhibited by sublethal postnatal stress. In premature infants, sublethal stress results mostly in organ maturation failure without excessive cellular demise.

Developmental emergence of fear/threat learning: neurobiology, associations and timing.

PubMed

Tallot, L; Doyère, V; Sullivan, R M

2016-01-01

Pavlovian fear or threat conditioning, where a neutral stimulus takes on aversive properties through pairing with an aversive stimulus, has been an important tool for exploring the neurobiology of learning. In the past decades, this neurobehavioral approach has been expanded to include the developing infant. Indeed, protracted postnatal brain development permits the exploration of how incorporating the amygdala, prefrontal cortex and hippocampus into this learning system impacts the acquisition and expression of aversive conditioning. Here, we review the developmental trajectory of these key brain areas involved in aversive conditioning and relate it to pups' transition to independence through weaning. Overall, the data suggests that adult-like features of threat learning emerge as the relevant brain areas become incorporated into this learning. Specifically, the developmental emergence of the amygdala permits cue learning and the emergence of the hippocampus permits context learning. We also describe unique features of learning in early life that block threat learning and enhance interaction with the mother or exploration of the environment. Finally, we describe the development of a sense of time within this learning and its involvement in creating associations. Together these data suggest that the development of threat learning is a useful tool for dissecting adult-like functioning of brain circuits, as well as providing unique insights into ecologically relevant developmental changes. © 2015 John Wiley & Sons Ltd and International Behavioural and Neural Genetics Society.

Fetal growth from mid- to late pregnancy is associated with infant development: the Generation R Study.

PubMed

Henrichs, Jens; Schenk, Jacqueline J; Barendregt, Charlotte S; Schmidt, Henk G; Steegers, Eric Ap; Hofman, Albert; Jaddoe, Vincent W V; Moll, Henriette A; Verhulst, Frank C; Tiemeier, Henning

2010-07-01

The aim of this study was to investigate within a population-based cohort of 4384 infants (2182 males, 2202 females) whether fetal growth from early pregnancy onwards is related to infant development and whether this potential relationship is independent of postnatal growth. Ultrasound measurements were performed in early, mid-, and late pregnancy. Estimated fetal weight was calculated using head and abdominal circumference and femur length. Infant development was measured with the Minnesota Infant Development Inventory at 12 months (SD 1.1mo, range 10-17mo). Information on postnatal head size and body weight at 7 months was obtained from medical records. After adjusting for potential confounders and for postnatal growth, faster fetal weight gain from mid- to late pregnancy predicted a reduced risk of delayed social development (odds ratio [OR] 0.82; 95% confidence interval [CI] 0.71-0.95, p=0.008), self-help abilities (OR 0.84; 95% CI 0.73-0.98, p=0.023), and overall infant development (OR 0.65; 95% CI 0.49-0.87, p=0.003). Similar findings were observed for fetal head growth from mid- to late pregnancy. Faster fetal growth predicts a lower risk of delayed infant development independent of postnatal growth. These results suggest that reduced fetal growth between mid- and late pregnancy may determine subsequent developmental outcomes.

The effects of microgravity on the development of surface righting in rats

PubMed Central

Walton, Kerry D; Harding, Shannon; Anschel, David; Harris, Ya'el Tobi; Llinás, Rodolfo

2005-01-01

The active interaction of neonatal animals with their environment has been shown to be a decisive factor in the postnatal development of sensory systems, which demonstrates a critical period in their maturation. The direct demonstration of such a dependence on the rearing environment has not been demonstrated for motor system function. Nor has the role of gravity in mammalian motor system development been investigated. Here we report the results of two space flight missions examining the effect of removing gravity on the development of surface righting. Since the essential stimulus that drives this synergy, gravitation, was missing, righting did not occur while the animals were in the microgravity environment. We hypothesize that this absence of contextual motor experience arrested the maturation of the motor tactics for surface righting. Such effects were permanent in rats spending 16 days (from postnatal day (P), P14 to P30), but were transient in animals spending nine days (from P15 to P24) in microgravity. Thus, active, contextual interaction with the environment during a critical period of development is necessary for the postnatal maturation of motor tactics as exemplified by surface righting, and such events must occur within a particular time period. Further, Earth's gravitational field is not assumed by the developing motor system. Rather, postnatal motor system development is appropriate to the gravitational field in which the animal is reared. PMID:15774538

Development of rat female genital cortex and control of female puberty by sexual touch

PubMed Central

Lenschow, Constanze; Sigl-Glöckner, Johanna

2017-01-01

Rat somatosensory cortex contains a large sexually monomorphic genital representation. Genital cortex undergoes an unusual 2-fold expansion during puberty. Here, we investigate genital cortex development and female rat sexual maturation. Ovariectomies and estradiol injections suggested sex hormones cause the pubertal genital cortex expansion but not its maintenance at adult size. Genital cortex expanded by thalamic afferents invading surrounding dysgranular cortex. Genital touch was a dominant factor driving female sexual maturation. Raising female rats in contact with adult males promoted genital cortex expansion, whereas contact to adult females or nontactile (audio-visual-olfactory) male cues did not. Genital touch imposed by human experimenters powerfully advanced female genital cortex development and sexual maturation. Long-term blocking of genital cortex by tetrodotoxin in pubescent females housed with males prevented genital cortex expansion and decelerated vaginal opening. Sex hormones, sexual experience, and neural activity shape genital cortex, which contributes to the puberty promoting effects of sexual touch. PMID:28934203

Development of rat female genital cortex and control of female puberty by sexual touch.

PubMed

Lenschow, Constanze; Sigl-Glöckner, Johanna; Brecht, Michael

2017-09-01

Rat somatosensory cortex contains a large sexually monomorphic genital representation. Genital cortex undergoes an unusual 2-fold expansion during puberty. Here, we investigate genital cortex development and female rat sexual maturation. Ovariectomies and estradiol injections suggested sex hormones cause the pubertal genital cortex expansion but not its maintenance at adult size. Genital cortex expanded by thalamic afferents invading surrounding dysgranular cortex. Genital touch was a dominant factor driving female sexual maturation. Raising female rats in contact with adult males promoted genital cortex expansion, whereas contact to adult females or nontactile (audio-visual-olfactory) male cues did not. Genital touch imposed by human experimenters powerfully advanced female genital cortex development and sexual maturation. Long-term blocking of genital cortex by tetrodotoxin in pubescent females housed with males prevented genital cortex expansion and decelerated vaginal opening. Sex hormones, sexual experience, and neural activity shape genital cortex, which contributes to the puberty promoting effects of sexual touch.

Outcome of prenatal depression and risk factors associated with persistence in the first postnatal year: prospective study from Rawalpindi, Pakistan.

PubMed

Rahman, Atif; Creed, Francis

2007-06-01

Rates of prenatal and postnatal depression in developing countries are high. Prolonged depression during the postnatal period is associated with impaired infant growth and development. Little is known about the factors predicting the persistence of prenatal depression beyond the first few postnatal months. From a sample of 701 women in a rural sub-district of Pakistan, the Schedule for Clinical Assessment in Neuropsychiatry (SCAN) was used to identify those with ICD-10 depressive disorder in the third trimester of pregnancy (n=160). Depressed women were re-assessed at 3, 6 and 12 months postnatal. Persistently depressed women (depressed at all time points) were compared with the remainder. Psychiatric symptoms, disability and life events were measured using the Self-Reporting Questionnaire (SRQ), Brief Disability Questionnaire (BDQ), and a modified Life Events Checklist. Of 129 mothers who completed follow-up, 73 (56%) were depressed at all points of assessment. These persistently depressed mothers had higher SRQ and BDQ scores prenatally and had experienced more life events in the year preceding the third pregnancy trimester than the mothers whose depressive disorder resolved (none received treatment). Persistent depression was significantly associated also with poverty, having 5 or more children, an uneducated husband and lack of a confidant or friend. On multivariate analysis, higher SRQ score and poverty during pregnancy predicted persistent depression. The sample was from one rural sub-district only. We did not assess the women for physical conditions such as anaemia and thyroid-deficiency. Women who are poor and have more psychological symptoms during pregnancy are more likely to remain depressed one year after giving birth. This study highlights the need for developing mechanisms of early identification and suitable psychosocial interventions to minimise the damaging effects of persistent postnatal depression in poor communities.

Postnatal care: development of a psychometric multidimensional satisfaction questionnaire (the WOMBPNSQ) to assess women's views.

PubMed

Smith, Lindsay F P

2011-10-01

Postnatal care is the neglected area of pregnancy care, despite repeated calls to improve it. Changes would require assessment, which should include women's views. No suitable satisfaction questionnaire exists to enable this. To develop a multidimensional psychometric postnatal satisfaction self-completion instrument. Ten maternity services in south west England from 2006-2009. Sources for questions were literature review, fieldwork, and related published instruments. Principal components analysis with varimax rotation was used to develop the final WOMen's views of Birth Postnatal Satisfaction Questionnaire (WOMBPNSQ) version. Validity and internal reliability were assessed. Questionnaires were mailed 6-8 weeks postnatally (with one reminder). The WOMBPNSQ comprises 36 seven-point Likert questions (13 dimensions including general satisfaction). Of 300 women, 166 (55.3%) replied; of these 155 (95.1 %) were white, 152 (93.8%) were married or cohabiting, 135 (81.3%) gave birth in a consultant unit, 129 (78.6%) had a vaginal delivery; and 100 (60.6%) were multiparous. The 12 specific dimensions were: support from professionals or partner, or social support; care from GP and health visitor; advice on contraception, feeding baby, the mother's health; continuity of care; duration of inpatient stay; home visiting; pain after birth. These have internal reliability (Cronbach's alpha varying from 0.624 to 0.902). Various demographic and clinical characteristics were significantly associated with specific dimensions. WOMBPNSQ could be used to assess existing or planned changes to maternity services or as a screening instrument, which would then enable in-depth qualitative assessment of areas of dissatisfaction. Its convergent validity and test-retest reliability are still to be assessed but are an improvement upon existing postnatal satisfaction questionnaires.

[Strategies for development, follow-up, and assessment of care provided to women in the pregnancy-postnatal cycle].

PubMed

Holanda, Cristyanne Samara Miranda de; Alchieri, João Carlos; Morais, Fátima Raquel Rosado; Maranhão, Técia Maria de Oliveira

2015-06-01

To describe the development of a questionnaire for assessment of prenatal, birth, and postnatal care (Inventário de Avaliação da Assistência ao Pré-natal, Parto e Puerpério, IAAPPP), which was designed taking into consideration the experience of users of a public obstetric service. This mixed methods research was performed in the city of Caicó, state of Rio Grande do Norte, Brazil. The study consisted of two phases: in phase 1, focal groups were organized with 19 users of the health care system for identification of relevant issues for assessment of the pregnancy-postnatal cycle. The first draft of the questionnaire was also designed and tested for validity with seven of the 19 focal group participants; a second draft was produced and retested. In phase 2, the intra-class correlation coefficient was calculated to determine reproducibility. A pilot test was carried out to determine the applicability of the survey and the final version of the IAAPPP was developed. Based on the focal group discussions, the inventory was organized into four domains: 1) socioeconomic information, 2) obstetric history, 3) description of current obstetric experience and 4) assessment of follow-up. Domains 3 and 4 were subdivided into prenatal care, birthcare, postnatal care, and pregnancy-postnatal cycle. The answers of the women who evaluated the instrument for domain 4 were strongly correlated (>0.8), indicating reproducibility of the IAAPPP. The methodological model allowed us to identify needs and demands of women in the pregnancy-postnatal cycle, and allowed us to design a questionnaire that can be applied to other regions with similar sociocultural characteristics.

Microglial numbers attain adult levels after undergoing a rapid decrease in cell number in the third postnatal week.

PubMed

Nikodemova, Maria; Kimyon, Rebecca S; De, Ishani; Small, Alissa L; Collier, Lara S; Watters, Jyoti J

2015-01-15

During postnatal development, microglia, CNS resident innate immune cells, are essential for synaptic pruning, neuronal apoptosis and remodeling. During this period microglia undergo morphological and phenotypic transformations; however, little is known about how microglial number and density is regulated during postnatal CNS development. We found that after an initial increase during the first 14 postnatal days, microglial numbers in mouse brain began declining in the third postnatal week and were reduced by 50% by 6weeks of age; these "adult" levels were maintained until at least 9months of age. Microglial CD11b levels increased, whereas CD45 and ER-MP58 declined between P10 and adulthood, consistent with a maturing microglial phenotype. Our data indicate that both increased microglial apoptosis and a decreased proliferative capacity contribute to the developmental reduction in microglial numbers. We found no correlation between developmental reductions in microglial numbers and brain mRNA levels of Cd200, Cx3Cl1, M-Csf or Il-34. We tested the ability of M-Csf-overexpression, a key growth factor promoting microglial proliferation and survival, to prevent microglial loss in the third postnatal week. Mice overexpressing M-Csf in astrocytes had higher numbers of microglia at all ages tested. However, the developmental decline in microglial numbers still occurred, suggesting that chronically elevated M-CSF is unable to overcome the developmental decrease in microglial numbers. Whereas the identity of the factor(s) regulating microglial number and density during development remains to be determined, it is likely that microglia respond to a "maturation" signal since the reduction in microglial numbers coincides with CNS maturation. Copyright © 2014 Elsevier B.V. All rights reserved.

The role of self-esteem instability in the development of postnatal depression: A prospective study testing a diathesis-stress account.

PubMed

Franck, Erik; Vanderhasselt, Marie-Anne; Goubert, Liesbet; Loeys, Tom; Temmerman, Marleen; De Raedt, Rudi

2016-03-01

Understanding vulnerability factors involved in the development of postnatal depression has important implications for theory and practice. In this prospective study, we investigated whether self-esteem instability during pregnancy would better predict postnatal depressive symptomatology than level of self-esteem. In addition, going beyond former studies, we tested the possible origin of this instability, examining whether day-to-day fluctuations in self-esteem could be explained by fluctuations in mood state, and whether this day-to-day self-esteem reactivity would predict postnatal depressive symptoms. 114 healthy never-depressed women were tested during the late second or third trimester of their gestation (Time 1) and at 12 weeks after delivery (Time 2). Day-to-day levels of self-esteem and depressed mood state were assessed at Time 1. At Time 2, postnatal depressive symptoms were assessed. The results show that, after controlling for initial depressive symptomatology, age and socio-economic status, postnatal depressive symptomatology at 12 weeks after childbirth could be predicted by self-esteem instability and not level of self-esteem. In addition, multi-level analyses demonstrated that these changes in day-to-day levels of self-esteem are associated with changes in day-to-day levels of depressed mood state and that those subjects with greater prenatal self-esteem reactivity upon depressed mood report higher levels of depressive symptoms post-partum. We used paper and pencil day-to-day measures of state self-esteem, which can be subject to bias. These results provide evidence for a diathesis-stress account of postnatal depression, highlighting the importance of a multi-dimensional view of self-esteem and the predictive role of self-esteem instability. Copyright © 2015 Elsevier Ltd. All rights reserved.

Postnatal dietary fatty acid composition permanently affects the structure of hypothalamic pathways controlling energy balance in mice.

PubMed

Schipper, Lidewij; Bouyer, Karine; Oosting, Annemarie; Simerly, Richard B; van der Beek, Eline M

2013-12-01

We previously reported that dietary lipid quality during early life can have long-lasting effects on metabolic health and adiposity. Exposure to a postnatal diet with low dietary omega-6 (n-6) or high omega-3 (n-3) fatty acid (FA) content resulted in reduced body fat accumulation when challenged with a moderate Western-style diet (WSD) beginning in adolescence. We determined whether this programming effect is accompanied by changes in hypothalamic neural projections or modifications in the postnatal leptin surge, which would indicate the altered development of hypothalamic circuits that control energy balance. Neonatal mice were subjected to a control diet (CTR) or experimental diet with altered relative n-6 and n-3 FA contents [ie, a diet with a relative reduction in n-6 fatty acid (LOW n-6) or a diet with a relative increase in n-3 fatty acid (HIGH n-3) compared with the CTR from postnatal day (PN) 2 to 42]. Compared with CTR mice, mice fed a LOW n-6 or HIGH n-3 during postnatal life showed significant reductions in the density of both orexigenic and anorexigenic neural projections to the paraventricular nucleus of the hypothalamus at PN 28. These impairments persisted into adulthood and were still apparent after the WSD challenge between PNs 42 and 98. However, the neuroanatomical changes were not associated with changes in the postnatal leptin surge. Although the exact mechanism remains to be elucidated, our data indicate that the quality of dietary FA during postnatal life affects the development of the central regulatory circuits that control energy balance and may do so through a leptin-independent mechanism.

Insights from Australian parents into educational experiences in the early postnatal period.

PubMed

McKellar, Lois V; Pincombe, Jan I; Henderson, Ann M

2006-12-01

to investigate the provision of parent education during the early postnatal period in order to gain insight that, through stakeholder collaboration, will contribute to the development of innovative strategies to enhance the provision of postnatal education in a contemporary health-care environment. the study comprises the first stage of an action-research project. The first stage of research sought to explore the experiences of mothers and fathers in the early postnatal period by conducting a questionnaire within 4 weeks of the birth of their baby. The data obtained from the questionnaire is to inform an action-research group for stage two of the project. The Children, Youth and Women's Health Service, a large city maternity hospital in South Australia, covering a range of socio-economic strata. 85 parents completed and returned the questionnaire, comprising 52 mothers and 33 fathers. an anonymous self-report questionnaire was purpose designed to provide each parent with an opportunity to reflect on their own experience, with particular emphasis given to the provision of education and support during the early postnatal period. a number of themes emerged, including a window of opportunity during the postnatal hospital stay to provide education and support, despite the reduction in the length of stay; the need for a family-centred approach to maternity services; and the significance of self and social network in the early transition to parenthood. The findings from this stage of the research, combined with a review of the literature, provide insight that will contribute to stage two of the study. At this stage, an action-research group will continue planning to develop specific actions to enhance the provision of education to parents in the early postnatal period. These actions will subsequently be implemented and assessed.

Mineral distributions at the developing tendon enthesis.

PubMed

Schwartz, Andrea G; Pasteris, Jill D; Genin, Guy M; Daulton, Tyrone L; Thomopoulos, Stavros

2012-01-01

Tendon attaches to bone across a functionally graded interface, "the enthesis". A gradient of mineral content is believed to play an important role for dissipation of stress concentrations at mature fibrocartilaginous interfaces. Surgical repair of injured tendon to bone often fails, suggesting that the enthesis does not regenerate in a healing setting. Understanding the development and the micro/nano-meter structure of this unique interface may provide novel insights for the improvement of repair strategies. This study monitored the development of transitional tissue at the murine supraspinatus tendon enthesis, which begins postnatally and is completed by postnatal day 28. The micrometer-scale distribution of mineral across the developing enthesis was studied by X-ray micro-computed tomography and Raman microprobe spectroscopy. Analyzed regions were identified and further studied by histomorphometry. The nanometer-scale distribution of mineral and collagen fibrils at the developing interface was studied using transmission electron microscopy (TEM). A zone (∼20 µm) exhibiting a gradient in mineral relative to collagen was detected at the leading edge of the hard-soft tissue interface as early as postnatal day 7. Nanocharacterization by TEM suggested that this mineral gradient arose from intrinsic surface roughness on the scale of tens of nanometers at the mineralized front. Microcomputed tomography measurements indicated increases in bone mineral density with time. Raman spectroscopy measurements revealed that the mineral-to-collagen ratio on the mineralized side of the interface was constant throughout postnatal development. An increase in the carbonate concentration of the apatite mineral phase over time suggested possible matrix remodeling during postnatal development. Comparison of Raman-based observations of localized mineral content with histomorphological features indicated that development of the graded mineralized interface is linked to endochondral bone formation near the tendon insertion. These conserved and time-varying aspects of interface composition may have important implications for the growth and mechanical stability of the tendon-to-bone attachment throughout development.

In utero heat stress increases postnatal core body temperature in pigs

USDA-ARS?s Scientific Manuscript database

In utero heat stress (IUHS) negatively impacts postnatal development, but how it alters future body temperature parameters and energetic metabolism is not well-understood. Objectives were to characterize future temperature indices and bioenergetic markers in pigs originating from differing in utero...

Major epigenetic development distinguishing neuronal and non-neuronal cells occurs postnatally in the murine hypothalamus

USDA-ARS?s Scientific Manuscript database

Prenatal and early postnatal environment can persistently alter one's risk of obesity. Environmental effects on hypothalamic developmental epigenetics constitute a likely mechanism underlying such 'developmental programming' of energy balance regulation. To advance our understanding of these process...

A structure-based extracellular matrix expansion mechanism of fibrous tissue growth

PubMed Central

Kalson, Nicholas S; Lu, Yinhui; Taylor, Susan H; Starborg, Tobias; Holmes, David F; Kadler, Karl E

2015-01-01

Embryonic growth occurs predominately by an increase in cell number; little is known about growth mechanisms later in development when fibrous tissues account for the bulk of adult vertebrate mass. We present a model for fibrous tissue growth based on 3D-electron microscopy of mouse tendon. We show that the number of collagen fibrils increases during embryonic development and then remains constant during postnatal growth. Embryonic growth was explained predominately by increases in fibril number and length. Postnatal growth arose predominately from increases in fibril length and diameter. A helical crimp structure was established in embryogenesis, and persisted postnatally. The data support a model where the shape and size of tendon is determined by the number and position of embryonic fibroblasts. The collagen fibrils that these cells synthesise provide a template for postnatal growth by structure-based matrix expansion. The model has important implications for growth of other fibrous tissues and fibrosis. DOI: http://dx.doi.org/10.7554/eLife.05958.001 PMID:25992598

Dietary sodium manipulation during critical periods in development sensitize adult offspring to amphetamines

PubMed Central

McBride, Shawna M.; Culver, Bruce; Flynn, Francis W.

2008-01-01

This study examined critical periods in development to determine when offspring were most susceptible to dietary sodium manipulation leading to amphetamine sensitization. Wistar dams (n = 6–8/group) were fed chow containing low (0.12% NaCl; LN), normal (1% NaCl; NN), or high sodium (4% NaCl; HN) during the prenatal or early postnatal period (birth to 5 wk). Offspring were fed normal chow thereafter until testing at 6 mo. Body weight (BW), blood pressure (BP), fluid intake, salt preference, response to amphetamine, open field behavior, plasma adrenocorticotropin hormone (ACTH), plasma corticosterone (Cort), and adrenal gland weight were measured. BW was similar for all offspring. Offspring from the prenatal and postnatal HN group had increased BP, NaCl intake, and salt preference and decreased water intake relative to NN offspring. Prenatal HN offspring had greater BP than postnatal HN offspring. In response to amphetamine, both prenatal and postnatal LN and HN offspring had increased locomotor behavior compared with NN offspring. In a novel open field environment, locomotion was also increased in prenatal and postnatal LN and HN offspring compared with NN offspring. ACTH and Cort levels 30 min after restraint stress and adrenal gland weight measurement were greater in LN and HN offspring compared with NN offspring. These results indicate that early life experience with low- and high-sodium diets, during the prenatal or early postnatal period, is a stress that produces long-term changes in responsiveness to amphetamines and to subsequent stressors. PMID:18614766

Atypical chemokine receptor ACKR2 controls branching morphogenesis in the developing mammary gland

PubMed Central

Hewit, Kay D.; Pallas, Kenneth J.; Cairney, Claire J.; Lee, Kit M.; Hansell, Christopher A.; Stein, Torsten

2017-01-01

Macrophages are important regulators of branching morphogenesis during development and postnatally in the mammary gland. Regulation of macrophage dynamics during these processes can therefore have a profound impact on development. We demonstrate here that the developing mammary gland expresses high levels of inflammatory CC-chemokines, which are essential in vivo regulators of macrophage migration. We further demonstrate that the atypical chemokine receptor ACKR2, which scavenges inflammatory CC-chemokines, is differentially expressed during mammary gland development. We have previously shown that ACKR2 regulates macrophage dynamics during lymphatic vessel development. Here, we extend these observations to reveal a novel role for ACKR2 in regulating the postnatal development of the mammary gland. Specifically, we show that Ackr2−/− mice display precocious mammary gland development. This is associated with increased macrophage recruitment to the developing gland and increased density of the ductal epithelial network. These data demonstrate that ACKR2 is an important regulator of branching morphogenesis in diverse biological contexts and provide the first evidence of a role for chemokines and their receptors in postnatal development processes. PMID:27888192

Understanding exercise self-efficacy and barriers to leisure-time physical activity among postnatal women.

PubMed

Cramp, Anita G; Bray, Steven R

2011-07-01

Studies have demonstrated that postnatal women are at high risk for physical inactivity and generally show lower levels of leisure-time physical activity (LTPA) compared to prepregnancy. The overall purpose of the current study was to investigate social cognitive correlates of LTPA among postnatal women during a 6-month period following childbirth. A total of 230 women (mean age = 30.9) provided descriptive data regarding barriers to LTPA and completed measures of LTPA and self-efficacy (exercise and barrier) for at least one of the study data collection periods. A total of 1,520 barriers were content analyzed. Both exercise and barrier self-efficacy were positively associated with subsequent LTPA. Exercise self-efficacy at postnatal week 12 predicted LTPA from postnatal weeks 12 to 18 (β = .40, R (2) = .18) and exercise self-efficacy at postnatal week 24 predicted LTPA during weeks 24-30 (β = .49, R (2) = .30). Barrier self-efficacy at week 18 predicted LTPA from weeks 18 to 24 (β = .33, R (2) = .13). The results of the study identify a number of barriers to LTPA at multiple time points closely following childbirth which may hinder initiation, resumption or maintenance of LTPA. The results also suggest that higher levels of exercise and barrier self-efficacy are prospectively associated with higher levels of LTPA in the early postnatal period. Future interventions should be designed to investigate causal effects of developing participants' exercise and barrier self-efficacy for promoting and maintaining LTPA during the postnatal period.

The Effect of Congenital and Postnatal Hypothyroidism on Depression-Like Behaviors in Juvenile Rats.

PubMed

Özgür, Erdoğan; Gürbüz Özgür, Börte; Aksu, Hatice; Cesur, Gökhan

2016-12-01

The aim of this study was to investigate depression-like behaviors of juvenile rats with congenital and postnatal hypothyroidism. Twenty-seven newborn rat pups were used. First, 6-month-old Wistar Albino female rats were impregnated. Methimazole (0.025% wt/vol) was given to dam rats from the first day of pregnancy until postnatal 21 days (P21) to generate pups with congenital hypothyroidism (n=8), whereas in the postnatal hypothyroidism group (n=10), methimazole was given from P0 to P21. In the control group (n=9), dam rats were fed ad libitum and normal tap water. Offspring were fed with breast milk from their mothers. The behavioral parameters were measured with the juvenile forced swimming test (JFST). The procedure of JFST consisted of two sessions in two consecutive days: the 15-minute pre-test on day 1 and the 5-minute test on day 2. Increased immobility and decreased climbing duration were observed in both congenital and postnatal hypothyroidism groups. Decreased swimming duration was detected in the postnatal hypothyroidism group. Both hypothyroidism groups had a lower body weight gain compared with the control group, while the congenital hypothyroidism group had the lowest body weight. Our results showed that hypothyroidism had negative effects on depression-like behavior as well as on growth and development. Both congenital and postnatal hypothyroidism caused an increase in immobility time in JFST. New studies are required to understand the differing results on depression-like behavior between congenital and postnatal hypothyroidism.

Non-School Influences and Educational Disadvantage: Pre and Post-natal Nutritional Deprivation

ERIC Educational Resources Information Center

Doll, Russell C.

1973-01-01

Deals with pre and post-natal malnutrition and its possible influence on the child, focusing on these points: How wide-spread and severe is the malnutrition? What might be the effects of the malnutrition at certain critical points in development? (Author/JM)

Metabolic perturbations of postnatal growth restriction and hyperoxia-induced pulmonary hypertension in a bronchopulmonary dysplasia model

USDA-ARS?s Scientific Manuscript database

Introduction: Neonatal pulmonary hypertension (PH) is a common manifestation of bronchopulmonary dysplasia (BPD) and contributes to increased morbidity and mortality of preterm birth. Postnatal growth restriction and hyperoxia are independent contributors to PH development, as indicated by our previ...