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Sample records for entorhinal cortex aspiration

  1. Functional subregions of the human entorhinal cortex

    PubMed Central

    Maass, Anne; Berron, David; Libby, Laura A; Ranganath, Charan; Düzel, Emrah

    2015-01-01

    The entorhinal cortex (EC) is the primary site of interactions between the neocortex and hippocampus. Studies in rodents and nonhuman primates suggest that EC can be divided into subregions that connect differentially with perirhinal cortex (PRC) vs parahippocampal cortex (PHC) and with hippocampal subfields along the proximo-distal axis. Here, we used high-resolution functional magnetic resonance imaging at 7 Tesla to identify functional subdivisions of the human EC. In two independent datasets, PRC showed preferential intrinsic functional connectivity with anterior-lateral EC and PHC with posterior-medial EC. These EC subregions, in turn, exhibited differential connectivity with proximal and distal subiculum. In contrast, connectivity of PRC and PHC with subiculum followed not only a proximal-distal but also an anterior-posterior gradient. Our data provide the first evidence that the human EC can be divided into functional subdivisions whose functional connectivity closely parallels the known anatomical connectivity patterns of the rodent and nonhuman primate EC. DOI: http://dx.doi.org/10.7554/eLife.06426.001 PMID:26052749

  2. Cellular properties of principal neurons in the rat entorhinal cortex. II. The medial entorhinal cortex.

    PubMed

    Canto, Cathrin B; Witter, Menno P

    2012-06-01

    Principal neurons in different medial entorhinal cortex (MEC) layers show variations in spatial modulation that stabilize between 15 and 30 days postnatally. These in vivo variations are likely due to differences in intrinsic membrane properties and integrative capacities of neurons. The latter depends on inputs and thus potentially on the morphology of principal neurons. In this comprehensive study, we systematically compared the morphological and physiological characteristics of principal neurons in all MEC layers of newborn rats before and after weaning. We recorded simultaneously from up to four post-hoc morphologically identified MEC principal neurons in vitro. Neurons in L(ayer) I-LIII have dendritic and axonal arbors mainly in superficial layers, and LVI neurons mainly in deep layers. The dendritic and axonal trees of part of LV neurons diverge throughout all layers. Physiological properties of principal neurons differ between layers. In LII, most neurons have a prominent sag potential, resonance and membrane oscillations. Neurons in LIII and LVI fire relatively regular, and lack sag potentials and membrane oscillations. LV neurons show the most prominent spike-frequency adaptation and highest input resistance. The data indicate that adult-like principal neuron types can be differentiated early on during postnatal development. The results of the accompanying paper, in which principal neurons in the lateral entorhinal cortex (LEC) were described (Canto and Witter,2011), revealed that significant differences between LEC and MEC exist mainly in LII neurons. We therefore systematically analyzed changes in LII biophysical properties along the mediolateral axis of MEC and LEC. There is a gradient in properties typical for MEC LII neurons. These properties are most pronounced in medially located neurons and become less apparent in more laterally positioned ones. This gradient continues into LEC, such that in LEC medially positioned neurons share some properties

  3. Structural development and dorsoventral maturation of the medial entorhinal cortex.

    PubMed

    Ray, Saikat; Brecht, Michael

    2016-04-02

    We investigated the structural development of superficial-layers of medial entorhinal cortex and parasubiculum in rats. The grid-layout and cholinergic-innervation of calbindin-positive pyramidal-cells in layer-2 emerged around birth while reelin-positive stellate-cells were scattered throughout development. Layer-3 and parasubiculum neurons had a transient calbindin-expression, which declined with age. Early postnatally, layer-2 pyramidal but not stellate-cells co-localized with doublecortin - a marker of immature neurons - suggesting delayed functional-maturation of pyramidal-cells. Three observations indicated a dorsal-to-ventral maturation of entorhinal cortex and parasubiculum: (i) calbindin-expression in layer-3 neurons decreased progressively from dorsal-to-ventral, (ii) doublecortin in layer-2 calbindin-positive-patches disappeared dorsally before ventrally, and (iii) wolframin-expression emerged earlier in dorsal than ventral parasubiculum. The early appearance of calbindin-pyramidal-grid-organization in layer-2 suggests that this pattern is instructed by genetic information rather than experience. Superficial-layer-microcircuits mature earlier in dorsal entorhinal cortex, where small spatial-scales are represented. Maturation of ventral-entorhinal-microcircuits - representing larger spatial-scales - follows later around the onset of exploratory behavior.

  4. Structural development and dorsoventral maturation of the medial entorhinal cortex

    PubMed Central

    Ray, Saikat; Brecht, Michael

    2016-01-01

    We investigated the structural development of superficial-layers of medial entorhinal cortex and parasubiculum in rats. The grid-layout and cholinergic-innervation of calbindin-positive pyramidal-cells in layer-2 emerged around birth while reelin-positive stellate-cells were scattered throughout development. Layer-3 and parasubiculum neurons had a transient calbindin-expression, which declined with age. Early postnatally, layer-2 pyramidal but not stellate-cells co-localized with doublecortin – a marker of immature neurons – suggesting delayed functional-maturation of pyramidal-cells. Three observations indicated a dorsal-to-ventral maturation of entorhinal cortex and parasubiculum: (i) calbindin-expression in layer-3 neurons decreased progressively from dorsal-to-ventral, (ii) doublecortin in layer-2 calbindin-positive-patches disappeared dorsally before ventrally, and (iii) wolframin-expression emerged earlier in dorsal than ventral parasubiculum. The early appearance of calbindin-pyramidal-grid-organization in layer-2 suggests that this pattern is instructed by genetic information rather than experience. Superficial-layer-microcircuits mature earlier in dorsal entorhinal cortex, where small spatial-scales are represented. Maturation of ventral-entorhinal-microcircuits – representing larger spatial-scales – follows later around the onset of exploratory behavior. DOI: http://dx.doi.org/10.7554/eLife.13343.001 PMID:27036175

  5. The role of the entorhinal cortex in paraphrenia.

    PubMed

    Casanova, Manuel F

    2010-06-01

    Evidence derived from postmortem brain studies has implicated the uncal cortex in paraphrenia. In the present review, we expand on the anatomic and physiologic nuances endogenous to this region that make entorhinal cortex pathology an important clinicopathological correlate to paraphrenia. First, we summarize the anatomic landmarks and histologic features that will allow the reader to define the entorhinal region in future research studies. As cortical regions usually project to neighboring cortices, inferences will be drawn as to the function of the entorhinal region based on the surrounding cortical regions. The results will help explain why patients with paraphrenia may exhibit amnestic deficits that stand in contrast to a well-preserved thought process and personality. We also review the results of surgical ablation studies in animals. These studies suggest that some risk factors currently associated with paraphrenia (eg, social isolation) may in reality be an early manifestation of entorhinal pathology. Finally, the author provides a parallelism between the hallucinations observed in some paraphrenic patients and the results of electrical stimulation of the uncal cortex. The results will help explain why hallucinations in paraphrenia are usually limited to the patient's surroundings.

  6. Effects of acetylcholine on neuronal properties in entorhinal cortex

    PubMed Central

    Heys, James G.; Schultheiss, Nathan W.; Shay, Christopher F.; Tsuno, Yusuke; Hasselmo, Michael E.

    2012-01-01

    The entorhinal cortex (EC) receives prominent cholinergic innervation from the medial septum and the vertical limb of the diagonal band of Broca (MSDB). To understand how cholinergic neurotransmission can modulate behavior, research has been directed toward identification of the specific cellular mechanisms in EC that can be modulated through cholinergic activity. This review focuses on intrinsic cellular properties of neurons in EC that may underlie functions such as working memory, spatial processing, and episodic memory. In particular, the study of stellate cells (SCs) in medial entorhinal has resulted in discovery of correlations between physiological properties of these neurons and properties of the unique spatial representation that is demonstrated through unit recordings of neurons in medial entorhinal cortex (mEC) from awake-behaving animals. A separate line of investigation has demonstrated persistent firing behavior among neurons in EC that is enhanced by cholinergic activity and could underlie working memory. There is also evidence that acetylcholine plays a role in modulation of synaptic transmission that could also enhance mnemonic function in EC. Finally, the local circuits of EC demonstrate a variety of interneuron physiology, which is also subject to cholinergic modulation. Together these effects alter the dynamics of EC to underlie the functional role of acetylcholine in memory. PMID:22837741

  7. Architecture of the Entorhinal Cortex A Review of Entorhinal Anatomy in Rodents with Some Comparative Notes.

    PubMed

    Witter, Menno P; Doan, Thanh P; Jacobsen, Bente; Nilssen, Eirik S; Ohara, Shinya

    2017-01-01

    The entorhinal cortex (EC) is the major input and output structure of the hippocampal formation, forming the nodal point in cortico-hippocampal circuits. Different division schemes including two or many more subdivisions have been proposed, but here we will argue that subdividing EC into two components, the lateral EC (LEC) and medial EC (MEC) might suffice to describe the functional architecture of EC. This subdivision then leads to an anatomical interpretation of the different phenotypes of LEC and MEC. First, we will briefly summarize the cytoarchitectonic differences and differences in hippocampal projection patterns on which the subdivision between LEC and MEC traditionally is based and provide a short comparative perspective. Second, we focus on main differences in cortical connectivity, leading to the conclusion that the apparent differences may well correlate with the functional differences. Cortical connectivity of MEC is features interactions with areas such as the presubiculum, parasubiculum, retrosplenial cortex (RSC) and postrhinal cortex, all areas that are considered to belong to the "spatial processing domain" of the cortex. In contrast, LEC is strongly connected with olfactory areas, insular, medial- and orbitofrontal areas and perirhinal cortex. These areas are likely more involved in processing of object information, attention and motivation. Third, we will compare the intrinsic networks involving principal- and inter-neurons in LEC and MEC. Together, these observations suggest that the different phenotypes of both EC subdivisions likely depend on the combination of intrinsic organization and specific sets of inputs. We further suggest a reappraisal of the notion of EC as a layered input-output structure for the hippocampal formation.

  8. Selective Vulnerability of Neurons in Layer II of the Entorhinal Cortex during Aging and Alzheimer's Disease

    PubMed Central

    Stranahan, Alexis M.; Mattson, Mark P.

    2010-01-01

    All neurons are not created equal. Certain cell populations in specific brain regions are more susceptible to age-related changes that initiate regional and system-level dysfunction. In this respect, neurons in layer II of the entorhinal cortex are selectively vulnerable in aging and Alzheimer's disease (AD). This paper will cover several hypotheses that attempt to account for age-related alterations among this cell population. We consider whether specific developmental, anatomical, or biochemical features of neurons in layer II of the entorhinal cortex contribute to their particular sensitivity to aging and AD. The entorhinal cortex is a functionally heterogeneous environment, and we will also review data suggesting that, within the entorhinal cortex, there is subregional specificity for molecular alterations that may initiate cognitive decline. Taken together, the existing data point to a regional cascade in which entorhinal cortical alterations directly contribute to downstream changes in its primary afferent region, the hippocampus. PMID:21331296

  9. Cholecystokinin from the entorhinal cortex enables neural plasticity in the auditory cortex.

    PubMed

    Li, Xiao; Yu, Kai; Zhang, Zicong; Sun, Wenjian; Yang, Zhou; Feng, Jingyu; Chen, Xi; Liu, Chun-Hua; Wang, Haitao; Guo, Yi Ping; He, Jufang

    2014-03-01

    Patients with damage to the medial temporal lobe show deficits in forming new declarative memories but can still recall older memories, suggesting that the medial temporal lobe is necessary for encoding memories in the neocortex. Here, we found that cortical projection neurons in the perirhinal and entorhinal cortices were mostly immunopositive for cholecystokinin (CCK). Local infusion of CCK in the auditory cortex of anesthetized rats induced plastic changes that enabled cortical neurons to potentiate their responses or to start responding to an auditory stimulus that was paired with a tone that robustly triggered action potentials. CCK infusion also enabled auditory neurons to start responding to a light stimulus that was paired with a noise burst. In vivo intracellular recordings in the auditory cortex showed that synaptic strength was potentiated after two pairings of presynaptic and postsynaptic activity in the presence of CCK. Infusion of a CCKB antagonist in the auditory cortex prevented the formation of a visuo-auditory association in awake rats. Finally, activation of the entorhinal cortex potentiated neuronal responses in the auditory cortex, which was suppressed by infusion of a CCKB antagonist. Together, these findings suggest that the medial temporal lobe influences neocortical plasticity via CCK-positive cortical projection neurons in the entorhinal cortex.

  10. Constraints on the synchronization of entorhinal cortex stellate cells

    NASA Astrophysics Data System (ADS)

    Crotty, Patrick; Lasker, Eric; Cheng, Sen

    2012-07-01

    Synchronized oscillations of large numbers of central neurons are believed to be important for a wide variety of cognitive functions, including long-term memory recall and spatial navigation. It is therefore plausible that evolution has optimized the biophysical properties of central neurons in some way for synchronized oscillations to occur. Here, we use computational models to investigate the relationships between the presumably genetically determined parameters of stellate cells in layer II of the entorhinal cortex and the ability of coupled populations of these cells to synchronize their intrinsic oscillations: in particular, we calculate the time it takes circuits of two or three cells with initially randomly distributed phases to synchronize their oscillations to within one action potential width, and the metabolic energy they consume in doing so. For recurrent circuit topologies, we find that parameters giving low intrinsic firing frequencies close to those actually observed are strongly advantageous for both synchronization time and metabolic energy consumption.

  11. Age effects on atrophy rates of entorhinal cortex and hippocampus

    PubMed Central

    Du, An-Tao; Schuff, Norbert; Chao, Linda L.; Kornak, John; Jagust, William J.; Kramer, Joel H.; Reed, Bruce R.; Miller, Bruce L.; Norman, David; Chui, Helena C.; Weiner, Michael W.

    2007-01-01

    The effects of age, subcortical vascular disease, apolipoprotein E (APOE) ɛ4 allele and hypertension on entorhinal cortex (ERC) and hippocampal atrophy rates were explored in a longitudinal MRI study with 42 cognitively normal (CN) elderly subjects from 58 to 87 years old. The volumes of the ERC, hippocampus, and white matter hyperintensities (WMH) and the presence of lacunes were assessed on MR images. Age was significantly associated with increased atrophy rates of 0.04 ± 0.02% per year for ERC and 0.05 ± 0.02% per year for hippocampus. Atrophy rates of hippocampus, but not that of ERC increased with presence of lacunes, in addition to age. WMH, APOE ɛ4 and hypertension had no significant effect on atrophy rates. In conclusion, age and presence of lacunes should be taken into consideration in imaging studies of CN subjects and AD patients to predict AD progression and assess the response to treatment trials. PMID:15961190

  12. Postnatal development of calcium-binding proteins immunoreactivity (parvalbumin, calbindin, calretinin) in the human entorhinal cortex.

    PubMed

    Grateron, L; Cebada-Sanchez, S; Marcos, P; Mohedano-Moriano, A; Insausti, A M; Muñoz, M; Arroyo-Jimenez, M M; Martinez-Marcos, A; Artacho-Perula, E; Blaizot, X; Insausti, R

    2003-12-01

    The entorhinal cortex is an essential component in the organization of the human hippocampal formation related to cortical activity. It transfers, neocortical information (ultimately distributed to the dentate gyrus and hippocampus) and receives most of the hippocampal output directed to neocortex. At birth, the human entorhinal cortex presents similar layer organization as in adults, although layer II (cell islands) and upper layer III have a protracted maturation. The presence of interneurons expressing calcium-binding proteins (parvalbumin, calbindin-D28K (calbindin) and calretinin) is well documented in the adult human entorhinal cortex. In many of them the calcium binding is co-localized with GABA. Parvalbumin-immunoreactive cells and fibers were virtually absent at birth, their presence increasing gradually in deep layer III, mostly in the lateral and caudal portions of the entorhinal cortex from the 5th month onwards. Calbindin immunoreactive cells and fibers were present at birth, mainly in layers II and upper III; mostly at rostral and lateral portions of the entorhinal cortex, increasing in number and extending to deep layers from the 5th month onwards. Calretinin immunoreactivity was present at birth, homogeneously distributed over layers I, II and upper V, throughout the entorhinal cortex. A substantial increase in the number of calretinin neurons in layer V was observed at the 5th month. The postnatal development of parvalbumin, calbindin and calretinin may have an important role in the functional maturation of the entorhinal cortex through the control of hippocampal, cortical and subcortical information.

  13. The role of the entorhinal cortex in extinction: influences of aging.

    PubMed

    Bevilaqua, Lia R M; Rossato, Janine I; Bonini, Juliana S; Myskiw, Jociane C; Clarke, Julia R; Monteiro, Siomara; Lima, Ramón H; Medina, Jorge H; Cammarota, Martín; Izquierdo, Iván

    2008-01-01

    The entorhinal cortex is perhaps the area of the brain in which neurofibrillary tangles and amyloid plaques are first detectable in old age with or without mild cognitive impairment, and very particularly in Alzheimer's disease. It plays a key role in memory formation, retrieval, and extinction, as part of circuits that include the hippocampus, the amygdaloid nucleus, and several regions of the neocortex, in particular of the prefrontal cortex. Lesions or biochemical impairments of the entorhinal cortex hinder extinction. Microinfusion experiments have shown that glutamate NMDA receptors, calcium and calmodulin-dependent protein kinase II, and protein synthesis in the entorhinal cortex are involved in and required for extinction. Aging also hinders extinction; it is possible that its effect may be in part mediated by the entorhinal cortex.

  14. Bilateral Entorhinal Cortex Lesions Impair Acquisition of Delayed Spatial Alternation in Rats.

    PubMed Central

    Ramirez, Julio J.; Campbell, David; Poulton, Nona; Barton, Cole; Swails, Jennifer; Geghman, Kindiya; Courchesne, Stephanie L.; Wentworth, Sean

    2007-01-01

    Entorhinal cortex lesions induce significant reorganization of several homotypic and heterotypic inputs to the hippocampus. This investigation determined whether surviving heterotypic inputs after bilateral entorhinal lesions would support the acquisition of a learned alternation task. Rats with entorhinal lesions or sham operations were trained to acquire a spatial alternation task. Although the sham-operated rats acquired the task within about three weeks postsurgery, rats with bilateral entorhinal lesions failed to learn the task after 12 consecutive weeks of training despite heterotypic sprouting of the cholinergic septodentate pathway and the expansion of the commissural/associational fiber plexus within the dentate gyrus. Thus, heterotypic sprouting failed to ameliorate significantly the effects of bilateral entorhinal lesions. Rather, entorhinal lesions produce a persistent impairment of spatial memory, characterized by a mixture of random error production and perseverative responding. PMID:17049284

  15. Effects of pre- or post-training entorhinal cortex AP5 injection on fear conditioning.

    PubMed

    Schenberg, Eduardo Ekman; Soares, Juliana Carlota Kramer; Oliveira, Maria Gabriela Menezes

    2005-11-15

    Fear conditioning is one of the most studied paradigms to assess the neural basis of emotional memory. The circuitry involves NMDA receptor activation in the amygdala and, in the case of contextual conditioning, in the hippocampus. Entorhinal cortex is one of the major input/output structures to the hippocampus and also projects to the amygdala, both through glutamatergic transmission. Other learning tasks involving hippocampus and amygdala, such as inhibitory avoidance, require entorhinal cortex during acquisition and consolidation. However, the involvement of NMDA receptors mediated transmission in entorhinal cortex in fear conditioning acquisition and consolidation is not clear. To investigate that issue, rats were trained in fear conditioning to both contextual and tone conditioned stimulus. Immediately before, immediately, 30 or 90 min after training they received NMDA antagonist AP5 or saline injections bilaterally in the entorhinal cortex (AP-6.8 mm, L +/-5.0 mm DV-6.8 mm). Contextual fear conditioning was measured 24 h after training, and tone fear conditioning 48 h after training. AP5 injections selectively impaired contextual fear conditioning only when injected pre-training. Post-training injections had no effect. These findings suggest that entorhinal cortex NMDA receptors are necessary for acquisition, but not for consolidation, of contextual fear conditioning. On the other hand, both acquisition and consolidation of tone fear conditioning seem to be independent of NMDA receptors in the entorhinal cortex.

  16. Interneurons spark seizure-like activity in the entorhinal cortex.

    PubMed

    Lévesque, Maxime; Herrington, Rochelle; Hamidi, Shabnam; Avoli, Massimo

    2016-03-01

    Excessive neuronal synchronization is presumably involved in epileptiform synchronization. However, the respective roles played by interneurons (GABAergic) and principal (glutamatergic) cells during interictal and ictal discharges remain unclear. Here, we employed tetrode wire recordings to establish the involvement of these two cell types in 4-aminopyridine-induced interictal- and low-voltage fast (LVF) onset ictal-like discharges in the rat entorhinal cortex in an in vitro slice preparation. We recorded a total of 90 single units (69 putative interneurons, 17 putative principal and 4 unclassified cells) from 36 slices, and found that: (i) interneurons (66.7%) were more likely to fire during interictal discharges than principal cells (35.3%); (ii) interneuron activity increased shortly before LVF ictal onset, whereas principal cell activity did not change; (iii) interneurons and principal cells fired at high rates throughout the tonic phase of the ictal discharge; however, (iv) only interneurons showed phase-locked relationship with LVF activity at 5-15Hz during the tonic phase. Finally, the association of interneuron firing with interictal discharges was maintained during blockade of ionotropic glutamatergic transmission. Our findings demonstrate the prominent involvement of interneurons in interictal discharge generation and in the transition to LVF ictal activity in this in vitro model of epileptiform synchronization.

  17. Optical coherence tomography visualizes neurons in human entorhinal cortex.

    PubMed

    Magnain, Caroline; Augustinack, Jean C; Konukoglu, Ender; Frosch, Matthew P; Sakadžić, Sava; Varjabedian, Ani; Garcia, Nathalie; Wedeen, Van J; Boas, David A; Fischl, Bruce

    2015-02-09

    The cytoarchitecture of the human brain is of great interest in diverse fields: neuroanatomy, neurology, neuroscience, and neuropathology. Traditional histology is a method that has been historically used to assess cell and fiber content in the ex vivo human brain. However, this technique suffers from significant distortions. We used a previously demonstrated optical coherence microscopy technique to image individual neurons in several square millimeters of en-face tissue blocks from layer II of the human entorhinal cortex, over 50 µm in depth. The same slices were then sectioned and stained for Nissl substance. We registered the optical coherence tomography (OCT) images with the corresponding Nissl stained slices using a nonlinear transformation. The neurons were then segmented in both images and we quantified the overlap. We show that OCT images contain information about neurons that is comparable to what can be obtained from Nissl staining, and thus can be used to assess the cytoarchitecture of the ex vivo human brain with minimal distortion. With the future integration of a vibratome into the OCT imaging rig, this technique can be scaled up to obtain undistorted volumetric data of centimeter cube tissue blocks in the near term, and entire human hemispheres in the future.

  18. A map of visual space in the primate entorhinal cortex.

    PubMed

    Killian, Nathaniel J; Jutras, Michael J; Buffalo, Elizabeth A

    2012-11-29

    Place-modulated activity among neurons in the hippocampal formation presents a means to organize contextual information in the service of memory formation and recall. One particular spatial representation, that of grid cells, has been observed in the entorhinal cortex (EC) of rats and bats, but has yet to be described in single units in primates. Here we examined spatial representations in the EC of head-fixed monkeys performing a free-viewing visual memory task. Individual neurons were identified in the primate EC that emitted action potentials when the monkey fixated multiple discrete locations in the visual field in each of many sequentially presented complex images. These firing fields possessed spatial periodicity similar to a triangular tiling with a corresponding well-defined hexagonal structure in the spatial autocorrelation. Further, these neurons showed theta-band oscillatory activity and changing spatial scale as a function of distance from the rhinal sulcus, which is consistent with previous findings in rodents. These spatial representations may provide a framework to anchor the encoding of stimulus content in a complex visual scene. Together, our results provide a direct demonstration of grid cells in the primate and suggest that EC neurons encode space during visual exploration, even without locomotion.

  19. GABAergic Somatostatin-immunoreactive Neurons in the Amygdala Project to the Entorhinal Cortex

    PubMed Central

    McDonald, Alexander J.; Zaric, Violeta

    2015-01-01

    The entorhinal cortex and other hippocampal and parahippocampal cortices are interconnected by a small number of GABAergic nonpyramidal neurons in addition to glutamatergic pyramidal cells. Since the cortical and basolateral amygdalar nuclei have cortex-like cell types and have robust projections to the entorhinal cortex, we hypothesized that a small number of amygdalar GABAergic nonpyramidal neurons might participate in amygdalo-entorhinal projections. To test this hypothesis we combined Fluorogold (FG) retrograde tract tracing with immunohistochemistry for the amygdalar nonpyramidal cell markers glutamic acid decarboxylase (GAD), parvalbumin (PV), somatostatin (SOM), neuropeptide Y (NPY), vasoactive intestinal peptide (VIP), and the m2 muscarinic cholinergic receptor (M2R). Injections of FG into the rat entorhinal cortex labeled numerous neurons that were mainly located in the cortical and basolateral nuclei of the amygdala. Although most of these amygdalar FG+ neurons labeled by entorhinal injections were large pyramidal cells, 1–5% were smaller long-range nonpyramidal neurons (LRNP neurons) that expressed SOM, or both SOM and NPY. No amygdalar FG+ neurons in these cases were PV+ or VIP+. Cell counts revealed that LRNP neurons labeled by injections into the entorhinal cortex constituted about 10–20% of the total SOM+ population, and 20–40% of the total NPY population in portions of the lateral amygdalar nucleus that exhibited a high density of FG+ neurons. Sixty-two percent of amygdalar FG+/SOM+ neurons were GAD+, and 51% were M2R+. Since GABAergic projection neurons typically have low perikaryal levels of GABAergic markers, it is actually possible that most or all of the amygdalar LRNP neurons are GABAergic. Like GABAergic LRNP neurons in hippocampal/parahippocampal regions, amygdalar LRNP neurons that project to the entorhinal cortex are most likely involved in synchronizing oscillatory activity between the two regions. These oscillations could entrain

  20. Autoradiographic study of the efferent connections of the entorhinal cortex in the rat

    SciTech Connect

    Wyss, J.M.

    1981-07-10

    The major findings can be summarized as follows. Whereas the projection of the lateral entorhinal area (LEA) to the dentate gyrus is broad in its longitudinal extent, the medial entorhinal area (MEA), and especially the ventral portion of this zone, projects in a more lamellar fashion. In the transverse plane the LEA preferentially projects to the inner (dorsal) blade of the dentate gyrus, while the MEA innervates both blades equally. Within the radial dimension, the entorhinal cortex projects to the dentate gyrus according to a medial to lateral gradient, with lateral portions of the LEA projecting along the pial surface and successively more medial portions of the entorhinal projecting closer to the granule cells. The commissural entorhinal to dentate projections are similar to the ipsilateral projections in location; however, they are considerably reduced in septotemporal extent and do not arise from cells in the ventral half of either LEA or the intermediate entorhinal area (IEA). The projection of the entorhinal cortex to Ammon's horn reflects the same longitudinal characteristics as the dentate projections. An alvear input which extends only to the pyramidal cells at the CA1-subicular junction was most noticeable at ventral hippocampal levels. The extrahippocampal projections arise predominantly from cells in the LEA and project forward along the angular bundle to the piriform and periamygdaloid cortices, as well as the endopiriform nucleus, the lateral, basolateral, and cortical amygdaloid nuclei, the nucleus of the lateral olfactory tract, the olfactory tubercle, the anterior olfactory nucleus, the taenia tecta, and the indusium griseum.

  1. Does the entorhinal cortex use the Fourier transform?

    PubMed Central

    Orchard, Jeff; Yang, Hao; Ji, Xiang

    2013-01-01

    Some neurons in the entorhinal cortex (EC) fire bursts when the animal occupies locations organized in a hexagonal grid pattern in their spatial environment. Place cells have also been observed, firing bursts only when the animal occupies a particular region of the environment. Both of these types of cells exhibit theta-cycle modulation, firing bursts in the 4–12 Hz range. Grid cells fire bursts of action potentials that precess with respect to the theta cycle, a phenomenon dubbed “theta precession.” Various models have been proposed to explain these phenomena, and how they relate to navigation. Among the most promising are the oscillator interference models. The bank-of-oscillators model proposed by Welday et al. (2011) exhibits all these features. However, their simulations are based on theoretical oscillators, and not implemented entirely with spiking neurons. We extend their work in a number of ways. First, we place the oscillators in a frequency domain and reformulate the model in terms of Fourier theory. Second, this perspective suggests a division of labor for implementing spatial maps: position vs. map layout. The animal's position is encoded in the phases of the oscillators, while the spatial map shape is encoded implicitly in the weights of the connections between the oscillators and the read-out nodes. Third, it reveals that the oscillator phases all need to conform to a linear relationship across the frequency domain. Fourth, we implement a partial model of the EC using spiking leaky integrate-and-fire (LIF) neurons. Fifth, we devise new coupling mechanisms, enlightened by the global phase constraint, and show they are capable of keeping spiking neural oscillators in consistent formation. Our model demonstrates place cells, grid cells, and phase precession. The Fourier model also gives direction for future investigations, such as integrating sensory feedback to combat drift, or explaining why grid cells exist at all. PMID:24376415

  2. Entorhinal cortex thickness predicts cognitive decline in Alzheimer's disease.

    PubMed

    Velayudhan, Latha; Proitsi, Petroula; Westman, Eric; Muehlboeck, J-Sebastian; Mecocci, Patrizia; Vellas, Bruno; Tsolaki, Magda; Kłoszewska, Iwona; Soininen, Hilkka; Spenger, Christian; Hodges, Angela; Powell, John; Lovestone, Simon; Simmons, Andrew

    2013-01-01

    Biomarkers for Alzheimer's disease (AD) based on non-invasive methods are highly desirable for diagnosis, disease progression, and monitoring therapeutics. We aimed to study the use of hippocampal volume, entorhinal cortex (ERC) thickness, and whole brain volume (WBV) as predictors of cognitive change in patients with AD. 120 AD subjects, 106 mild cognitive impairment (MCI), and 99 non demented controls (NDC) from the multi-center pan-European AddNeuroMed study underwent MRI scanning at baseline and clinical evaluations at quarterly follow-up up to 1 year. The rate of cognitive decline was estimated using cognitive outcomes, Mini-Mental State Examination (MMSE) and Alzheimer disease assessment scale-cognitive (ADAS-cog) by fitting a random intercept and slope model. AD subjects had smaller ERC thickness and hippocampal and WBV volumes compared to MCI and NDC subjects. Within the AD group, ERC > WBV was significantly associated with baseline cognition (MMSE, ADAS-cog) and disease severity (Clinical Dementia Rating). Baseline ERC thickness was associated with both longitudinal MMSE and ADAS-cog score changes and WBV with ADAS-cog decline. These data indicate that AD subjects with thinner ERC had lower baseline cognitive scores, higher disease severity, and predicted greater subsequent cognitive decline at one year follow up. ERC is a region known to be affected early in the disease. Therefore, the rate of atrophy in this structure is expected to be higher since neurodegeneration begins earlier. Focusing on structural analyses that predict decline can identify those individuals at greatest risk for future cognitive loss. This may have potential for increasing the efficacy of early intervention.

  3. Parvalbumin-immunoreactive neurons in the entorhinal cortex of the rat: localization, morphology, connectivity and ultrastructure.

    PubMed

    Wouterlood, F G; Härtig, W; Brückner, G; Witter, M P

    1995-02-01

    We studied the distribution, morphology, ultrastructure and connectivity of parvalbumin-immunoreactive neurons in the entorhinal cortex of the rat. Immunoreactive cell bodies were found in all layers of the entorhinal cortex except layer I. The highest numbers were observed in layers II and III of the dorsal division of the lateral entorhinal area whereas the lowest numbers occurred in the ventral division of the lateral entorhinal area. Most such neurons displayed multipolar configurations with smooth dendrites. We distinguished a type with long dendrites and a type with short dendrites. We also observed pyramidal immunoreactive neurons. A dense plexus of immunoreactive dendrites and axons was prominent in layers II and III of the dorsal division of the lateral entorhinal area and the medial entorhinal area. None of the parvalbumin-immunoreactive cells became retrogradely labelled after injection of horseradish peroxidase into the hippocampal formation. By electron microscopy, immunoreactivity was observed in cell bodies, dendrites, myelinated and unmyelinated axons and axon terminals. Immunoreactive dendrites and axons occurred in all cortical layers. We noted many myelinated immunoreactive axons. Immunoreactive axon terminals were medium sized, contained pleomorphic synaptic vesicles, and established symmetrical synapses. Both horseradish peroxidase labelled and unlabelled immunonegative cell bodies often received synapses from immunopositive axon terminals arranged in baskets. Synapses between immunoreactive axon terminals and unlabelled dendritic shafts and spines were abundant. Synapses with initial axon segments occurred less frequently. In addition, synaptic contacts were present between immunopositive axon terminals and cell bodies and dendrites. Thus, the several types of parvalbumin-containing neuron in the entorhinal cortex are interneurons, connected to one another and to immunonegative neurons through a network of synaptic contacts. Immunonegative

  4. Postsynaptic Signals Mediating Induction of Long-Term Synaptic Depression in the Entorhinal Cortex

    PubMed Central

    Kourrich, Saïd; Glasgow, Stephen D.; Caruana, Douglas A.; Chapman, C. Andrew

    2008-01-01

    The entorhinal cortex receives a large projection from the piriform cortex, and synaptic plasticity in this pathway may affect olfactory processing. In vitro whole cell recordings have been used here to investigate postsynaptic signalling mechanisms that mediate the induction of long-term synaptic depression (LTD) in layer II entorhinal cortex cells. To induce LTD, pairs of pulses, using a 30-millisecond interval, were delivered at 1 Hz for 15 minutes. Induction of LTD was blocked by the NMDA receptor antagonist APV and by the calcium chelator BAPTA, consistent with a requirement for calcium influx via NMDA receptors. Induction of LTD was blocked when the FK506 was included in the intracellular solution to block the phosphatase calcineurin. Okadaic acid, which blocks activation of protein phosphatases 1 and 2a, also prevented LTD. Activation of protein phosphatases following calcium influx therefore contributes to induction of LTD in layer II of the entorhinal cortex. PMID:18670611

  5. Morphology of spiny neurons in the human entorhinal cortex: intracellular filling with lucifer yellow.

    PubMed

    Mikkonen, M; Pitkänen, A; Soininen, H; Alafuzoff, I; Miettinen, R

    2000-01-01

    The present study was designed to investigate the morphology of spiny neurons in the human entorhinal cortex. Coronal entorhinal slices (n = 67; 200 microm thick) were obtained from autopsies of three subjects. Spiny neurons (n = 132) filled with Lucifer Yellow were analysed in different subfields and layers of the entorhinal cortex. Based on the shape of the somata and primary dendritic trees, spiny neurons were divided into four morphological categories; (i) classical pyramidal, (ii) stellate, (iii) modified stellate, and (iv) horizontal tripolar cells. The morphology of filled neurons varied more in different layers than in the different subfields of the entorhinal cortex. In layer II, the majority (81%) of spiny neurons had stellate or modified stellate morphology, but in the rostromedial subfields (olfactory subfield and rostral subfield) there were also horizontal tripolar neurons. Dendritic branches of layer II neurons extended to layer I (94%) and to layer III (83%). Unlike in layer II, most (74%) of the filled neurons in layers III, V and VI were classical pyramidal cells. The majority of pyramidal cells in the superficial portion of layer III had dendrites that extended up to layer II, occupying the space between the neuronal clusters. Some dendrites reached down to the deep portion of layer III. Apical dendrites of layer V and VI pyramidal cells traveled up to the deep portion of layer III.Our data indicate that the morphology of spiny neurons in different layers of the human entorhinal cortex is variable. Vertical extension of dendritic branches to adjacent layers supports the idea that inputs terminating in a specific lamina influence target cells located in various entorhinal layers. There appears to be more overlap in the dendritic fields between superficial layers II and III than between the superficial (II/III) and deep (V/VI) layers, thus supporting the idea of segregation of information flow targeted to the superficial or deep layers in the human

  6. Knife cuts of entorhinal cortex: effects on development of amygdaloid kindling and seizure-induced decrease of muscarinic cholinergic receptors

    SciTech Connect

    Savage, D.D.; Rigsbee, L.C.; McNamara, J.O.

    1985-02-01

    This report examines the effect of transection of the entorhinal hippocampal projection on amygdaloid kindling. We found that: bilateral knife cuts of entorhinal cortex but not of dorsal neocortex antagonize the development of amygdaloid kindling; and bilateral knife cuts of entorhinal cortex eliminate the seizure-induced decrease in number of muscarinic receptors of dentate granule cells. We suggest the following interpretations of these data: the hippocampal formation circuitry facilitates the development of amygdaloid kindling; and the decline of muscarinic receptors after kindled seizures is due to excessive activation of granule cells by axons from entorhinal cortex, a noncholinergic afferent.

  7. Depression, hypothalamic pituitary adrenal axis, and hippocampal and entorhinal cortex volumes--the SMART Medea study.

    PubMed

    Gerritsen, Lotte; Comijs, Hannie C; van der Graaf, Yolanda; Knoops, Arnoud J G; Penninx, Brenda W J H; Geerlings, Mirjam I

    2011-08-15

    Structural brain changes have often been found in major depressive disorder (MDD), and it is thought that hypothalamic-pituitary-adrenal (HPA) axis hyperactivity may explain this relation. We investigated the association of MDD and history of depression with hippocampal and entorhinal cortex volumes and whether HPA axis activity explained this association. In 636 participants with a history of atherosclerotic disease (mean age 62 ± 9 years, 81% male) from the second Manifestation of ARTerial disease-Memory depression and aging (SMART-Medea) study, a 12-month diagnosis of MDD and history of depression were assessed. Age of first depressive episode was classified into early-onset depression (< 50 years) and late-onset depression (≥ 50 years). HPA axis regulation was assessed by four morning saliva samples, two evening samples, and one awakening sample after .5 mg dexamethasone. Hippocampus and entorhinal cortex volume were manually outlined on three-dimensional T1-weighted magnetic resonance images. General linear models adjusted for demographics, vascular risk, antidepressant use, and white matter lesions showed that ever having had MDD was associated with smaller hippocampal volumes but not with entorhinal cortex volumes. Remitted MDD was related to smaller entorhinal cortex volumes (p < .05). Participants with early-onset depression had smaller hippocampal volumes than those who were never depressed (p < .05), whereas participants with late-onset depression had smaller entorhinal cortex volumes (p < .05). HPA axis activity did not explain these differences. We found differential associations of age of onset of depression on hippocampal and entorhinal cortex volumes, which could not be explained by alterations in HPA axis regulation. Copyright © 2011 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.

  8. FOCAL EXPRESSION OF MUTATED TAU IN ENTORHINAL CORTEX NEURONS OF RATS IMPAIRS SPATIAL WORKING MEMORY

    PubMed Central

    Ramirez, Julio J.; Poulton, Winona E.; Knelson, Erik; Barton, Cole; King, Michael A.; Klein, Ronald L.

    2010-01-01

    Entorhinal cortex neuropathology begins very early in Alzheimer's disease (AD), a disorder characterized by severe memory disruption. Indeed, loss of entorhinal volume is predictive of AD and two of the hallmark neuroanatomical markers of AD, amyloid plaques and neurofibrillary tangles (NFTs), are particularly prevalent in the entorhinal area of AD-afflicted brains. Gene transfer techniques were used to create a model neurofibrillary tauopathy by injecting a recombinant adeno-associated viral vector with a mutated human tau gene (P301L) into the entorhinal cortex of adult rats. The objective of the present investigation was to determine whether adult onset, spatially restricted tauopathy could be sufficient to reproduce progressive deficits in mnemonic function. Spatial memory on a Y-maze was tested for approximately three months post-surgery. Upon completion of behavioral testing the brains were assessed for expression of human tau and evidence of tauopathy. Rats injected with the tau vector became persistently impaired on the task after about six weeks of postoperative testing, whereas the control rats injected with a green fluorescent protein vector performed at criterion levels during that period. Histological analysis confirmed the presence of hyperphosphorylated tau and NFTs in the entorhinal cortex and neighboring retrohippocampal areas as well as limited synaptic degeneration of the perforant path. Thus, highly restricted vector-induced tauopathy in retrohippocampal areas is sufficient for producing progressive impairment in mnemonic ability in rats, successfully mimicking a key aspect of tauopathies such as AD. PMID:20727915

  9. Rebound spiking properties of mouse medial entorhinal cortex neurons in vivo.

    PubMed

    Tsuno, Yusuke; Chapman, George W; Hasselmo, Michael E

    2015-12-01

    The medial entorhinal cortex is the gateway between the cortex and hippocampus, and plays a critical role in spatial coding as represented by grid cell activity. In the medial entorhinal cortex, inhibitory circuits are robust, and the presence of the h-current leads to rebound potentials and rebound spiking in in vitro experiments. It has been hypothesized that these properties, combined with network oscillations, may contribute to grid cell formation. To examine the properties of in vivo rebound spikes, we performed whole-cell patch-clamp recordings in medial entorhinal cortex neurons in anaesthetized mice. We injected hyperpolarizing inputs representing inhibitory synaptic inputs along with sinusoidal oscillations and found that hyperpolarizing inputs injected at specific phases of oscillation had a higher probability of inducing subsequent spikes at the peak of the oscillation in some neurons. This effect was prominent in the cells with large sag potential, which is a marker of the h-current. In addition, larger and longer hyperpolarizing current square-pulse stimulation resulted in a larger probability of eliciting rebound spikes, though we did not observe a relationship between the amplitude or duration of hyperpolarizing current pulse stimulation and the delay of rebound spikes. Overall these results suggest that rebound spikes are observed in vivo and may play a role in generating grid cell activity in medial entorhinal cortex neurons. © 2015 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

  10. Rebound spiking properties of mouse medial entorhinal cortex neurons in vivo

    PubMed Central

    Tsuno, Yusuke; Chapman, G. William; Hasselmo, Michael E.

    2016-01-01

    Medial entorhinal cortex is the gateway between cortex and hippocampus, and plays a critical role for spatial coding as represented by grid cell activity. In the medial entorhinal cortex, inhibitory circuits are robust, and the presence of h-current leads to rebound potentials and rebound spiking in in vitro experiments. It has been hypothesized that these properties, combined with local field potential oscillations, may contribute to grid cell formation. To examine the properties of in vivo rebound spikes, we performed whole cell patch clamp recordings in medial entorhinal cortex neurons in anesthetized mice. We injected hyperpolarizing inputs representing inhibitory synaptic inputs with sinusoidal oscillations and found that hyperpolarizing inputs injected at specific phases of oscillation had higher probability of inducing subsequent spikes at the peak of the oscillation in some neurons. Also, this effect was prominent in the cells with large sag potential which is a marker of h-current. In addition, larger and longer hyperpolarizing current square pulse stimulation resulted in a larger probability of eliciting rebound spikes. We did not observe a relationship between amplitude or duration of hyperpolarizing current pulse stimulation and the delay of rebound spikes. These results suggest that rebound spikes are observed in vivo and may play a role in generating grid cell activity in medial entorhinal cortex neurons. PMID:26454151

  11. Cellular, columnar and modular organization of spatial representations in medial entorhinal cortex.

    PubMed

    Burgalossi, Andrea; Brecht, Michael

    2014-02-01

    Spatial discharge patterns in medial entorhinal cortex consist of grid, head direction, border and spatial-band cells. These firing patterns differ from the single-peaked fields of hippocampal place cells, in that they have well-defined geometries and extend throughout the available space. Such discharge properties could contribute to a metric representation of space. Both functional and anatomical evidence point to principal cell diversity, modularity and columnar organization, but linking entorhinal anatomy and physiology remains challenging. Layer 2 microcircuits consist of pyramidal neurons and a stellate cell network, which lacks recurrent excitation and is coupled by disynaptic inhibition. Intracellular recordings showed that periodic, grid-like firing emerges from depolarization ramps, whereas theta-oscillations determine spike timing. Interference with various inputs to entorhinal cortex abolishes grid activity, often without concomitant loss of hippocampal place activity.

  12. Conserved size and periodicity of pyramidal patches in layer 2 of medial/caudal entorhinal cortex.

    PubMed

    Naumann, Robert K; Ray, Saikat; Prokop, Stefan; Las, Liora; Heppner, Frank L; Brecht, Michael

    2016-03-01

    To understand the structural basis of grid cell activity, we compare medial entorhinal cortex architecture in layer 2 across five mammalian species (Etruscan shrews, mice, rats, Egyptian fruit bats, and humans), bridging ∼100 million years of evolutionary diversity. Principal neurons in layer 2 are divided into two distinct cell types, pyramidal and stellate, based on morphology, immunoreactivity, and functional properties. We confirm the existence of patches of calbindin-positive pyramidal cells across these species, arranged periodically according to analyses techniques like spatial autocorrelation, grid scores, and modifiable areal unit analysis. In rodents, which show sustained theta oscillations in entorhinal cortex, cholinergic innervation targeted calbindin patches. In bats and humans, which only show intermittent entorhinal theta activity, cholinergic innervation avoided calbindin patches. The organization of calbindin-negative and calbindin-positive cells showed marked differences in entorhinal subregions of the human brain. Layer 2 of the rodent medial and the human caudal entorhinal cortex were structurally similar in that in both species patches of calbindin-positive pyramidal cells were superimposed on scattered stellate cells. The number of calbindin-positive neurons in a patch increased from ∼80 in Etruscan shrews to ∼800 in humans, only an ∼10-fold over a 20,000-fold difference in brain size. The relatively constant size of calbindin patches differs from cortical modules such as barrels, which scale with brain size. Thus, selective pressure appears to conserve the distribution of stellate and pyramidal cells, periodic arrangement of calbindin patches, and relatively constant neuron number in calbindin patches in medial/caudal entorhinal cortex.

  13. Conserved size and periodicity of pyramidal patches in layer 2 of medial/caudal entorhinal cortex

    PubMed Central

    Naumann, Robert K.; Ray, Saikat; Prokop, Stefan; Las, Liora; Heppner, Frank L.

    2016-01-01

    ABSTRACT To understand the structural basis of grid cell activity, we compare medial entorhinal cortex architecture in layer 2 across five mammalian species (Etruscan shrews, mice, rats, Egyptian fruit bats, and humans), bridging ∼100 million years of evolutionary diversity. Principal neurons in layer 2 are divided into two distinct cell types, pyramidal and stellate, based on morphology, immunoreactivity, and functional properties. We confirm the existence of patches of calbindin‐positive pyramidal cells across these species, arranged periodically according to analyses techniques like spatial autocorrelation, grid scores, and modifiable areal unit analysis. In rodents, which show sustained theta oscillations in entorhinal cortex, cholinergic innervation targeted calbindin patches. In bats and humans, which only show intermittent entorhinal theta activity, cholinergic innervation avoided calbindin patches. The organization of calbindin‐negative and calbindin‐positive cells showed marked differences in entorhinal subregions of the human brain. Layer 2 of the rodent medial and the human caudal entorhinal cortex were structurally similar in that in both species patches of calbindin‐positive pyramidal cells were superimposed on scattered stellate cells. The number of calbindin‐positive neurons in a patch increased from ∼80 in Etruscan shrews to ∼800 in humans, only an ∼10‐fold over a 20,000‐fold difference in brain size. The relatively constant size of calbindin patches differs from cortical modules such as barrels, which scale with brain size. Thus, selective pressure appears to conserve the distribution of stellate and pyramidal cells, periodic arrangement of calbindin patches, and relatively constant neuron number in calbindin patches in medial/caudal entorhinal cortex. J. Comp. Neurol. 524:783–806, 2016. © 2015 The Authors. The Journal of Comparative Neurology Published by Wiley Periodicals, Inc. PMID:26223342

  14. Contributions of the hippocampus and entorhinal cortex to rapid visuomotor learning in rhesus monkeys

    PubMed Central

    Yang, Tianming; Bavley, Rachel L.; Fomalont, Kevin; Blomstrom, Kevin J.; Mitz, Andrew R.; Turchi, Janita; Rudebeck, Peter H.; Murray, Elisabeth A.

    2014-01-01

    The hippocampus and adjacent structures in the medial temporal lobe are essential for establishing new associative memories. Despite this knowledge, it is not known whether the hippocampus proper is essential for establishing such memories, nor is it known whether adjacent regions like the entorhinal cortex might contribute. To test the contributions of these regions to the formation of new associative memories, we trained rhesus monkeys to rapidly acquire arbitrary visuomotor associations, i.e., associations between visual stimuli and spatially directed actions. We then assessed the effects of reversible inactivations of either the hippocampus (Experiment 1) or entorhinal cortex (Experiment 2) on the within-session rate of learning. For comparison we also evaluated the effects of the inactivations on performance of problems of the same type that had been well learned prior to any inactivations. We found that inactivation of the entorhinal cortex but not hippocampus produced impairments in acquiring novel arbitrary associations. The impairment did not extend to the familiar, previously established associations. These data indicate that the entorhinal cortex is causally involved in establishing new associations, as opposed to retrieving previously learned associations. PMID:24753214

  15. Contributions of the hippocampus and entorhinal cortex to rapid visuomotor learning in rhesus monkeys.

    PubMed

    Yang, Tianming; Bavley, Rachel L; Fomalont, Kevin; Blomstrom, Kevin J; Mitz, Andrew R; Turchi, Janita; Rudebeck, Peter H; Murray, Elisabeth A

    2014-09-01

    The hippocampus and adjacent structures in the medial temporal lobe are essential for establishing new associative memories. Despite this knowledge, it is not known whether the hippocampus proper is essential for establishing such memories, nor is it known whether adjacent regions like the entorhinal cortex might contribute. To test the contributions of these regions to the formation of new associative memories, we trained rhesus monkeys to rapidly acquire arbitrary visuomotor associations, i.e., associations between visual stimuli and spatially directed actions. We then assessed the effects of reversible inactivations of either the hippocampus (Experiment 1) or entorhinal cortex (Experiment 2) on the within-session rate of learning. For comparison, we also evaluated the effects of the inactivations on performance of problems of the same type that had been well learned prior to any inactivations. We found that inactivation of the entorhinal cortex but not hippocampus produced impairments in acquiring novel arbitrary associations. The impairment did not extend to the familiar, previously established associations. These data indicate that the entorhinal cortex is causally involved in establishing new associations, as opposed to retrieving previously learned associations. Published 2014. This article is a U.S. Government work and is in the public domain in the USA.

  16. Two Alzheimer’s disease risk genes increase entorhinal cortex volume in young adults

    PubMed Central

    DiBattista, Amanda Marie; Stevens, Benson W.; Rebeck, G. William; Green, Adam E.

    2014-01-01

    Alzheimer’s disease (AD) risk genes alter brain structure and function decades before disease onset. Apolipoprotein E (APOE) is the strongest known genetic risk factor for AD, and a related gene, apolipoprotein J (APOJ), also affects disease risk. However, the extent to which these genes affect brain structure in young adults remains unclear. Here, we report that AD risk alleles of these two genes, APOE-ε4 and APOJ-C, cumulatively alter brain volume in young adults. Using voxel-based morphometry (VBM) in 57 individuals, we examined the entorhinal cortex, one of the earliest brain regions affected in AD pathogenesis. Apolipoprotein E-ε4 carriers exhibited higher right entorhinal cortex volume compared to non-carriers. Interestingly, APOJ-C risk genotype was associated with higher bilateral entorhinal cortex volume in non-APOE-ε4 carriers. To determine the combined disease risk of APOE and APOJ status per subject, we used cumulative odds ratios as regressors for volumetric measurements. Higher disease risk corresponded to greater right entorhinal cortex volume. These results suggest that, years before disease onset, two key AD genetic risk factors may exert influence on the structure of a brain region where AD pathogenesis takes root. PMID:25339884

  17. Selective lesion to the entorhinal cortex leads to an impairment in familiarity but not recollection.

    PubMed

    Brandt, Karen R; Eysenck, Michael W; Nielsen, Maria Kragh; von Oertzen, Tim J

    2016-04-01

    The present research explored the effects of selective impairment to the entorhinal cortex on the processes of familiarity and recollection. To achieve this objective, the performance of patient MR, who has a selective impairment of the left entorhinal cortex, was compared to that of age and IQ-matched controls. Four experiments tested participants' recognition memory for familiar and unfamiliar faces and words. In all experiments, participants studied lists of items and then completed an old/new recognition test in which they also made remember/know/guess judgements. A fifth experiment tested participants' priming associated with the familiarity process. MR had intact performance in both face recognition experiments as well as having intact performance in pseudoword recognition. Crucially, however, in the familiar word experiment, whilst MR performed similarly to control participants in terms of recollection, she showed a marked impairment in familiarity. Furthermore, she also demonstrated a reversed conceptual priming effect. MR's impairment is both material-specific and selective for previously encountered but not new verbal items (pseudowords). These findings provide the first clear evidence that selective impairment of the entorhinal cortex impairs the familiarity process for familiar verbal material whilst leaving recollection intact. These results suggest the entorhinal cortex does not have attributes reflective of both recollection and familiarity as previously assumed, but rather supports context-free long-term familiarity-based recognition memory.

  18. Reduced Spiking in Entorhinal Cortex during the Delay Period of a Cued Spatial Response Task

    ERIC Educational Resources Information Center

    Gupta, Kishan; Keller, Lauren A.; Hasselmo, Michael E.

    2012-01-01

    Intrinsic persistent spiking mechanisms in medial entorhinal cortex (mEC) neurons may play a role in active maintenance of working memory. However, electrophysiological studies of rat mEC units have primarily focused on spatial modulation. We sought evidence of differential spike rates in the mEC in rats trained on a T-maze, cued spatial delayed…

  19. Reduced Spiking in Entorhinal Cortex during the Delay Period of a Cued Spatial Response Task

    ERIC Educational Resources Information Center

    Gupta, Kishan; Keller, Lauren A.; Hasselmo, Michael E.

    2012-01-01

    Intrinsic persistent spiking mechanisms in medial entorhinal cortex (mEC) neurons may play a role in active maintenance of working memory. However, electrophysiological studies of rat mEC units have primarily focused on spatial modulation. We sought evidence of differential spike rates in the mEC in rats trained on a T-maze, cued spatial delayed…

  20. Effect of early isolation on signal transfer in the entorhinal cortex-dentate-hippocampal system.

    PubMed

    Bartesaghi, R; Raffi, M; Ciani, E

    2006-02-01

    Deprivation of socio-sensory interactions during early life impairs brain function in adulthood. In previous investigations we showed that early isolation severely affects neuron development in several structures of the hippocampal region, including the entorhinal cortex. In the present study we investigated the effects of early isolation on signal processing along the entorhinal cortex-dentate-CA3-CA1 system, a major memory circuit of the hippocampal region. Male and female guinea-pigs were assigned at 6-7 days of age to either a social or an isolated environment. At 90-100 days of age the animals were anesthetized and field potentials were recorded from the entorhinal cortex-dentate-CA3-CA1 circuit, driven by dorsal psalterium commissural volleys. Analysis of the input-output function in the different structures showed that in isolated males there was a small reduction in the input-output function of the population excitatory postsynaptic potential and population spike evoked in layer II of the entorhinal cortex. No changes occurred in isolated females. In isolated males and females there was a reduction in the input-output function of the population excitatory postsynaptic potential and population spike evoked in the dentate gyrus, CA3 and CA1, but this effect was larger in males. In isolated males, but not in females, the population spike/population excitatory postsynaptic potential ratio was reduced in all investigated structures, indicating that in males the size of the discharged neuron population was reduced more than due to the decreased input. Results show that isolation reduces the synaptic function in the whole entorhinal cortex-dentate gyrus-CA3-CA1 system. While the entorhinal cortex was moderately impaired, the dentate-hippocampal system was more severely affected. The impairment in the signal transfer along the entorhinal cortex-dentate gyrus-CA3-CA1 system was heavier in males, confirming the larger susceptibility of this sex to early experience

  1. 6-Hydroxydopamine and radiofrequency lesions of the lateral entorhinal cortex facilitate an operant appetitive conditioning task in mice.

    PubMed

    Gauthier, M; Soumireu-Mourat, B

    1981-07-02

    The entorhinal cortex seems heterogeneous as dopaminergic terminals are present only in the anterior part of the lateral entorhinal cortex. In order to clarify the interaction of this cortex with the hippocampus in memory processes, the effects of either 6-hydroxydopamine or radiofrequency bilateral lesions were compared. Both lesions enhance the retention of a Skinner task with continuous reinforcement schedule. Involvement of dopamine in memory processes is discussed.

  2. Medial entorhinal cortex lesions only partially disrupt hippocampal place cells and hippocampus-dependent place memory

    PubMed Central

    Hales, Jena B; Schlesiger, Magdalene I; Leutgeb, Jill K; Squire, Larry R; Leutgeb, Stefan; Clark, Robert E

    2014-01-01

    SUMMARY Entorhinal cortex provides the primary cortical projections to the hippocampus, a brain structure critical for memory. However, it remains unclear how the precise firing patterns of medial entorhinal cortex (MEC) cells influence hippocampal physiology and hippocampus-dependent behavior. We found that complete bilateral lesions of MEC resulted in a lower proportion of active hippocampal cells. The remaining active cells had place fields, but with decreased spatial precision and decreased long-term spatial stability. In addition, MEC rats were as impaired at acquiring the watermaze as hippocampus rats, while rats with combined MEC and hippocampal lesions had an even greater deficit. However, MEC rats were not impaired on other hippocampus-dependent tasks, including those in which an object location or context was remembered. Thus, MEC is not necessary for all types of spatial coding, nor for all types of hippocampus-dependent memory, but is necessary for the normal acquisition of place memory. PMID:25437546

  3. Running Induces Widespread Structural Alterations in the Hippocampus and Entorhinal Cortex

    PubMed Central

    Stranahan, Alexis M.; Khalil, David; Gould, Elizabeth

    2010-01-01

    Physical activity enhances hippocampal function but its effects on neuronal structure remain relatively unexplored outside of the dentate gyrus. Using Golgi impregnation and the lipophilic tracer DiI, we show that long-term voluntary running increases the density of dendritic spines in the entorhinal cortex and hippocampus of adult rats. Exercise was associated with increased dendritic spine density not only in granule neurons of the dentate gyrus, but also in CA1 pyramidal neurons, and in layer III pyramidal neurons of the entorhinal cortex. In the CA1 region, changes in dendritic spine density are accompanied by changes in dendritic arborization and alterations in the morphology of individual spines. These findings suggest that physical activity exerts pervasive effects on neuronal morphology in the hippocampus and one of its afferent populations. These structural changes may contribute to running-induced changes in cognitive function. PMID:17636549

  4. Neuronal rebound spiking, resonance frequency and theta cycle skipping may contribute to grid cell firing in medial entorhinal cortex

    PubMed Central

    Hasselmo, Michael E.

    2014-01-01

    Data show a relationship of cellular resonance and network oscillations in the entorhinal cortex to the spatial periodicity of grid cells. This paper presents a model that simulates the resonance and rebound spiking properties of entorhinal neurons to generate spatial periodicity dependent upon phasic input from medial septum. The model shows that a difference in spatial periodicity can result from a difference in neuronal resonance frequency that replicates data from several experiments. The model also demonstrates a functional role for the phenomenon of theta cycle skipping in the medial entorhinal cortex. PMID:24366135

  5. Entorhinal cortex pre-alpha cell clusters in schizophrenia: quantitative evidence of a developmental abnormality.

    PubMed

    Falkai, P; Schneider-Axmann, T; Honer, W G

    2000-06-01

    Previous studies using semiquantitative or qualitative techniques demonstrated abnormalities of positioning of clusters of neurons (pre-alpha cells) in the entorhinal cortex in schizophrenia, suggesting a developmental mechanism could contribute to the illness. Recent quantitative studies of laminar thickness and laminar cell counts have been less consistent, and several failed to replicate the finding. However, none of the quantitative studies focused on the position of the pre-alpha cell clusters. To study pre-alpha cell position in detail, we examined the entorhinal cortex in serial sections from 21 control and 19 schizophrenic brains. Cluster position relative to the gray-white matter junction and cluster size were measured. Quantitative assessment of 1991 clusters indicated clusters were positioned relatively closer to the gray-white matter junction in the anterior half of schizophrenic entorhinal cortices. In addition, the size of clusters in males with schizophrenia was reduced. These results support the model of schizophrenia as an illness in which brain development is impaired. The findings in males with schizophrenia may indicate the presence of more severe pathology, or an additional pathogenic mechanism.

  6. Entorhinal cortex volume is associated with episodic memory related brain activation in normal aging and amnesic mild cognitive impairment.

    PubMed

    Trivedi, Mehul A; Stoub, Travis R; Murphy, Christopher M; George, Sarah; deToledo-Morrell, Leyla; Shah, Raj C; Whitfield-Gabrieli, Susan; Gabrieli, John D E; Stebbins, Glenn T

    2011-06-01

    The present study examined the relationship between entorhinal cortex and hippocampal volume with fMRI activation during episodic memory function in elderly controls with no cognitive impairment and individuals with amnesic mild cognitive impairment (aMCI). Both groups displayed limited evidence for a relationship between hippocampal volume and fMRI activation. Smaller right entorhinal cortex volume was correlated with reduced activation in left and right medial frontal cortex (BA 8) during incidental encoding for both aMCI and elderly controls. However, during recognition, smaller left entorhinal cortex volume correlated with reduced activation in right BA 8 for the control group, but greater activation for the aMCI group. There was no significant relationship between entorhinal cortex volume and activation during intentional encoding in either group. The recognition-related dissociation in structure/function relationships in aMCI paralleled our behavioral findings, where individuals with aMCI displayed poorer performance relative to controls during recognition, but not encoding. Taken together, these results suggest that the relationship between entorhinal cortex volume and fMRI activation during episodic memory function is altered in individuals with aMCI.

  7. Entorhinal cortex volume is associated with episodic memory related brain activation in normal aging and amnesic mild cognitive impairment

    PubMed Central

    Trivedi, Mehul A.; Stoub, Travis R.; Murphy, Christopher M.; George, Sarah; deToledo-Morrell, Leyla; Shah, Raj C.; Whitfield-Gabrieli, Susan; Gabrieli, John D.E.; Stebbins, Glenn T.

    2011-01-01

    The present study examined the relationship between entorhinal cortex and hippocampal volume with fMRI activation during episodic memory function in elderly controls with no cognitive impairment and individuals with amnesic mild cognitive impairment (aMCI). Both groups displayed limited evidence for a relationship between hippocampal volume and fMRI activation. Smaller right entorhinal cortex volume was correlated with reduced activation in left and right medial frontal cortex (BA 8) during incidental encoding for both aMCI and elderly controls. However, during recognition, smaller left entorhinal cortex volume correlated with reduced activation in right BA 8 for the control group, but greater activation for the aMCI group. There was no significant relationship between entorhinal cortex volume and activation during intentional encoding in either group. The recognition-related dissociation in structure/function relationships in aMCI paralleled our behavioral findings, where individuals with aMCI displayed poorer performance relative to controls during recognition, but not encoding. Taken together, these results suggest that the relationship between entorhinal cortex volume and fMRI activation during episodic memory function is altered in individuals with aMCI. PMID:21328083

  8. Effects of unilateral entorhinal cortex lesion on retention of water maze performance.

    PubMed

    Glasier, M M; Janis, L S; Roof, R L; Stein, D G

    1999-01-01

    In a previous study, adult male Sprague-Dawley rats with unilateral, electrolytic entorhinal cortex lesions showed significant deficits in acquisition of a water maze task that measured working memory. The 10 days of testing used two trials per day with an intertrial interval of 1 h, and the rats with entorhinal damage were impaired in total distance to the platform in both trials. In the present retention study, rats who learned the same task prior to injury and were then retested for 5 days after lesion showed only a first day deficit in total distance to platform in the second trial. Analysis of swim patterns indicated that rats with unilateral entorhinal lesions used an altered strategy in retention testing to find the platform in the second trial of each day and incorporated the use of headings appropriate for Trial 1 only. This altered or compensatory strategy was not the optimum choice for problem solution. Although the rats then were able to switch headings and find the platform without significant impairment in total distance to platform on days 2-5 of testing, the use of an initial incorrect strategy indicated subtle residual deficits in cue integration and use of working memory. Copyright 1999 Academic Press.

  9. Context-dependent spatially periodic activity in the human entorhinal cortex.

    PubMed

    Nadasdy, Zoltan; Nguyen, T Peter; Török, Ágoston; Shen, Jason Y; Briggs, Deborah E; Modur, Pradeep N; Buchanan, Robert J

    2017-04-10

    The spatially periodic activity of grid cells in the entorhinal cortex (EC) of the rodent, primate, and human provides a coordinate system that, together with the hippocampus, informs an individual of its location relative to the environment and encodes the memory of that location. Among the most defining features of grid-cell activity are the 60° rotational symmetry of grids and preservation of grid scale across environments. Grid cells, however, do display a limited degree of adaptation to environments. It remains unclear if this level of environment invariance generalizes to human grid-cell analogs, where the relative contribution of visual input to the multimodal sensory input of the EC is significantly larger than in rodents. Patients diagnosed with nontractable epilepsy who were implanted with entorhinal cortical electrodes performing virtual navigation tasks to memorized locations enabled us to investigate associations between grid-like patterns and environment. Here, we report that the activity of human entorhinal cortical neurons exhibits adaptive scaling in grid period, grid orientation, and rotational symmetry in close association with changes in environment size, shape, and visual cues, suggesting scale invariance of the frequency, rather than the wavelength, of spatially periodic activity. Our results demonstrate that neurons in the human EC represent space with an enhanced flexibility relative to neurons in rodents because they are endowed with adaptive scalability and context dependency.

  10. Deep layer neurons in the rat medial entorhinal cortex fire sparsely irrespective of spatial novelty.

    PubMed

    Burgalossi, Andrea; von Heimendahl, Moritz; Brecht, Michael

    2014-01-01

    Extracellular recordings in medial entorhinal cortex have revealed the existence of spatially-modulated firing patterns, which are thought to contribute to a cognitive map of external space. Previous work indicated that during exploration of novel environments, spiking activity in deep entorhinal layers is much sparser than in superficial layers. In the present report, we ask whether this laminar activity profile is a consequence of environmental novelty. We report on a large dataset of juxtacellularly-recorded neurons (n = 70) whose spiking activity was monitored while rats explored either a novel or a familiar environment, or both within the same session. Irrespective of previous knowledge of the environment, deep layer activity was very low during exploration (median firing rate 0.4 Hz for non-silent cells), with a large fraction of silent cells (n = 19 of a total 37), while superficial layer activity was several times higher (median firing rate 2.4 Hz; n = 33). The persistence of laminar differences in firing activity both under environmental novelty and familiarity, and even in head-restrained stationary animals, suggests that sparse coding might be a constitutive feature of deep entorhinal layers.

  11. Grid cell hexagonal patterns formed by fast self-organized learning within entorhinal cortex.

    PubMed

    Mhatre, Himanshu; Gorchetchnikov, Anatoli; Grossberg, Stephen

    2012-02-01

    Grid cells in the dorsal segment of the medial entorhinal cortex (dMEC) show remarkable hexagonal activity patterns, at multiple spatial scales, during spatial navigation. It has previously been shown how a self-organizing map can convert firing patterns across entorhinal grid cells into hippocampal place cells that are capable of representing much larger spatial scales. Can grid cell firing fields also arise during navigation through learning within a self-organizing map? This article describes a simple and general mathematical property of the trigonometry of spatial navigation which favors hexagonal patterns. The article also develops a neural model that can learn to exploit this trigonometric relationship. This GRIDSmap self-organizing map model converts path integration signals into hexagonal grid cell patterns of multiple scales. GRIDSmap creates only grid cell firing patterns with the observed hexagonal structure, predicts how these hexagonal patterns can be learned from experience, and can process biologically plausible neural input and output signals during navigation. These results support an emerging unified computational framework based on a hierarchy of self-organizing maps for explaining how entorhinal-hippocampal interactions support spatial navigation.

  12. Context-dependent spatially periodic activity in the human entorhinal cortex

    PubMed Central

    Nguyen, T. Peter; Török, Ágoston; Shen, Jason Y.; Briggs, Deborah E.; Modur, Pradeep N.; Buchanan, Robert J.

    2017-01-01

    The spatially periodic activity of grid cells in the entorhinal cortex (EC) of the rodent, primate, and human provides a coordinate system that, together with the hippocampus, informs an individual of its location relative to the environment and encodes the memory of that location. Among the most defining features of grid-cell activity are the 60° rotational symmetry of grids and preservation of grid scale across environments. Grid cells, however, do display a limited degree of adaptation to environments. It remains unclear if this level of environment invariance generalizes to human grid-cell analogs, where the relative contribution of visual input to the multimodal sensory input of the EC is significantly larger than in rodents. Patients diagnosed with nontractable epilepsy who were implanted with entorhinal cortical electrodes performing virtual navigation tasks to memorized locations enabled us to investigate associations between grid-like patterns and environment. Here, we report that the activity of human entorhinal cortical neurons exhibits adaptive scaling in grid period, grid orientation, and rotational symmetry in close association with changes in environment size, shape, and visual cues, suggesting scale invariance of the frequency, rather than the wavelength, of spatially periodic activity. Our results demonstrate that neurons in the human EC represent space with an enhanced flexibility relative to neurons in rodents because they are endowed with adaptive scalability and context dependency. PMID:28396399

  13. Signal transduction mechanisms within the entorhinal cortex that support latent inhibition of cued fear conditioning.

    PubMed

    Lewis, Michael C; Gould, Thomas J

    2007-10-01

    Latent inhibition is a phenomenon by which pre-exposure to a conditioned-stimulus (CS), prior to subsequent pairings of that same CS with an unconditioned-stimulus (US), results in decreased conditioned responding to the CS. Previous work in our laboratory has suggested that the entorhinal cortex is critically involved in the establishment of latent inhibition of cued fear conditioning. Furthermore, utilizing systemic pharmacology, we have demonstrated a role for of NMDA receptors, protein kinase A (PKA), and mitogen activated protein kinase (MAPK, also known as ERK) in latent inhibition of cued fear conditioning, but until now, where these cell signaling cascades are critically activated during latent inhibition of cued fear was unknown. Here, we use direct drug infusion to demonstrate that cell signaling via NMDA receptors, the cAMP/PKA pathway, and the MAPK pathway within the entorhinal cortex are critically involved in latent inhibition of cued fear conditioning. In the present study, CS pre-exposed mice received 20 CS pre-exposures 24h prior to two pairings of the same CS with a 0.53 mA foot shock US, while control animals receive no pre-exposure to the CS. The NMDA antagonist APV (0.25 or 2.5 microg/side), the cAMP inhibitor Rp-cAMP (1.8 or 18.0 microg/side), or the MAPK inhibitor U0126 (0.1 or 1.0 microg/side) were directly infused into the entorhinal cortex prior to pre-exposure. All three drugs produced dose-dependent disruptions in latent inhibition of cued fear conditioning. Importantly, none of the drugs had any effect on cued fear conditioning when administered on training day, suggesting that the effects of each of the drugs were specific to CS pre-exposure. These results are discussed in relation to the potential mechanisms of plasticity that support latent inhibition of cued fear conditioning.

  14. Inhibition of TRPV1 channels enables long-term potentiation in the entorhinal cortex.

    PubMed

    Banke, Tue G

    2016-04-01

    The transient receptor potential vanilloid 1 (TRPV1) channel is a non-selective cation channel that is mainly found in nociceptive neurons of the peripheral nervous system; however, these channels have also been located within the CNS, including the entorhinal cortex. Whole-cell patch-clamp recordings of principal entorhinal cortex (EC) layers II/III neurons revealed that evoked inhibitory postsynaptic currents were depressed by application of the TRPV1 agonist capsaicin (CAP), accompanied by a change in the pair-pulse ratio (PPR). In addition, recordings of miniature inhibitory postsynaptic currents (mIPSCs) revealed that inter-event intervals but not amplitude were decreased in wild-type (WT) after application of CAP. This suggests that TRPV1 channels are functional in the entorhinal cortex and are located on inhibitory neurons with their axonal arborization within layers II/III. In order to study TRPV1 channels and their involvement in long-term potentiation (LTP) induction in a more intact circuit, extracellular field potential recordings were performed in EC layers II/III. It was found that activated TRPV1 channels preclude induction of long-term potentiation. In sharp contrast, clear LTP was observed when antagonizing TRPV1 channels or recording from TRPV1 knock-out mice. Thus, these results suggests that signaling through activating inhibitory presynaptic TRPV1 channels represents a novel mechanism by which a shift in feed-forward inhibition of layers II/III cortical principal neurons prompt changes in synaptic strength and thereby contribute to a change of information storage within the brain.

  15. Infusion of protein synthesis inhibitors in the entorhinal cortex blocks consolidation but not reconsolidation of object recognition memory.

    PubMed

    Lima, Ramón H; Rossato, Janine I; Furini, Cristiane R; Bevilaqua, Lia R; Izquierdo, Iván; Cammarota, Martín

    2009-05-01

    Memory consolidation and reconsolidation require the induction of protein synthesis in some areas of the brain. Here, we show that infusion of the protein synthesis inhibitors anisomycin, emetine and cycloheximide in the entorhinal cortex immediately but not 180 min or 360 min after training in an object recognition learning task hinders long-term memory retention without affecting short-term memory or behavioral performance. Inhibition of protein synthesis in the entorhinal cortex after memory reactivation involving either a combination of familiar and novel objects or two familiar objects does not affect retention. Our data suggest that protein synthesis in the entorhinal cortex is necessary early after training for consolidation of object recognition memory. However, inhibition of protein synthesis in this cortical region after memory retrieval does not seem to affect the stability of the recognition trace.

  16. Persistent short term memory deficits in Hebb-Williams maze performance are shown by rats with unilateral entorhinal cortex lesions.

    PubMed

    Glasier, M M; Janis, L S; Stein, D G

    1997-02-01

    The spatial abilities of adult, male Sprague-Dawley rats in the Hebb-Williams maze were examined at 6 months after unilateral electrolytic entorhinal cortex lesions. Compared with sham-operated rats, their performance was impaired in both initial entry and repeat entry errors over 12 consecutive problems, using immediate starting replacement for the 6 trials per problem. The configurations of the 12 maze problems are independent, and deficits were seen over the entire course of the testing. This study indicates that Hebb-Williams maze performance deficits after unilateral entorhinal cortex lesion are persistent and can be seen up to 6 months after injury.

  17. Lateral entorhinal cortex is necessary for associative but not nonassociative recognition memory

    PubMed Central

    Wilson, David IG; Watanabe, Sakurako; Milner, Helen; Ainge, James A

    2013-01-01

    The lateral entorhinal cortex (LEC) provides one of the two major input pathways to the hippocampus and has been suggested to process the nonspatial contextual details of episodic memory. Combined with spatial information from the medial entorhinal cortex it is hypothesised that this contextual information is used to form an integrated spatially selective, context-specific response in the hippocampus that underlies episodic memory. Recently, we reported that the LEC is required for recognition of objects that have been experienced in a specific context (Wilson et al. (2013) Hippocampus 23:352-366). Here, we sought to extend this work to assess the role of the LEC in recognition of all associative combinations of objects, places and contexts within an episode. Unlike controls, rats with excitotoxic lesions of the LEC showed no evidence of recognizing familiar combinations of object in place, place in context, or object in place and context. However, LEC lesioned rats showed normal recognition of objects and places independently from each other (nonassociative recognition). Together with our previous findings, these data suggest that the LEC is critical for associative recognition memory and may bind together information relating to objects, places, and contexts needed for episodic memory formation. PMID:23836525

  18. Optogenetic dissection of ictal propagation in the hippocampal–entorhinal cortex structures

    PubMed Central

    Lu, Yi; Zhong, Cheng; Wang, Lulu; Wei, Pengfei; He, Wei; Huang, Kang; Zhang, Yi; Zhan, Yang; Feng, Guoping; Wang, Liping

    2016-01-01

    Temporal lobe epilepsy (TLE) is one of the most common drug-resistant forms of epilepsy in adults and usually originates in the hippocampal formations. However, both the network mechanisms that support the seizure spread and the exact directions of ictal propagation remain largely unknown. Here we report the dissection of ictal propagation in the hippocampal–entorhinal cortex (HP–EC) structures using optogenetic methods in multiple brain regions of a kainic acid-induced model of TLE in VGAT-ChR2 transgenic mice. We perform highly temporally precise cross-area analyses of epileptic neuronal networks and find a feed-forward propagation pathway of ictal discharges from the dentate gyrus/hilus (DGH) to the medial entorhinal cortex, instead of a re-entrant loop. We also demonstrate that activating DGH GABAergic interneurons can significantly inhibit the spread of ictal seizures and largely rescue behavioural deficits in kainate-exposed animals. These findings may shed light on future therapeutic treatments of TLE. PMID:26997093

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

    PubMed

    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.

  20. Functional double dissociation within the entorhinal cortex for visual scene-dependent choice behavior

    PubMed Central

    Yoo, Seung-Woo; Lee, Inah

    2017-01-01

    How visual scene memory is processed differentially by the upstream structures of the hippocampus is largely unknown. We sought to dissociate functionally the lateral and medial subdivisions of the entorhinal cortex (LEC and MEC, respectively) in visual scene-dependent tasks by temporarily inactivating the LEC and MEC in the same rat. When the rat made spatial choices in a T-maze using visual scenes displayed on LCD screens, the inactivation of the MEC but not the LEC produced severe deficits in performance. However, when the task required the animal to push a jar or to dig in the sand in the jar using the same scene stimuli, the LEC but not the MEC became important. Our findings suggest that the entorhinal cortex is critical for scene-dependent mnemonic behavior, and the response modality may interact with a sensory modality to determine the involvement of the LEC and MEC in scene-based memory tasks. DOI: http://dx.doi.org/10.7554/eLife.21543.001 PMID:28169828

  1. Persistent déjà vu associated with hyperperfusion in the entorhinal cortex.

    PubMed

    Takeda, Youji; Kurita, Tsugiko; Sakurai, Kotaro; Shiga, Tohru; Tamaki, Nagara; Koyama, Tsukasa

    2011-06-01

    Déjà vu is a common experience among the normal population. However, in individuals with temporal lobe epilepsy, it often occurs as a seizure manifestation. The specific cause of such déjà vu is not yet known. Here, we report a case of epilepsy with persistent déjà vu. The patient described the state as if he were living the same life he had lived before. Blood perfusion single-photon-emission computed tomography (SPECT) performed during the persistent déjà vu showed hyperperfusion in the left medial temporal area; discontinuation of déjà vu was accompanied by disappearance of the hyperperfused area on SPECT. Analysis with three-dimensional co-registration of SPECT and MRI revealed that the hyperperfused area during the persistent déjà vu was in the entorhinal cortex of the left temporal lobe. According to recent theories of recognition memory, malfunction of the parahippocampal area may cause déjà vu. It is also suggested that epileptic activity in the parahippocampal area, especially the entorhinal cortex, may elicit déjà vu. Copyright © 2011 Elsevier Inc. All rights reserved.

  2. Medial entorhinal cortex and medial septum contribute to self-motion-based linear distance estimation.

    PubMed

    Jacob, Pierre-Yves; Gordillo-Salas, Marta; Facchini, Justine; Poucet, Bruno; Save, Etienne; Sargolini, Francesca

    2017-02-04

    Path integration is a navigation strategy that requires animals to integrate self-movements during exploration to determine their position in space. The medial entorhinal cortex (MEC) has been suggested to play a pivotal role in this process. Grid cells, head-direction cells, border cells as well as speed cells within the MEC collectively provide a dynamic representation of the animal position in space based on the integration of self-movements. All these cells are strongly modulated by theta oscillations, thus suggesting that theta rhythmicity in the MEC may be essential for integrating and coordinating self-movement information during navigation. In this study, we first show that excitotoxic MEC lesions, but not dorsal hippocampal lesions, impair the ability of rats to estimate linear distances based on self-movement information. Next, we report similar deficits following medial septum inactivation, which strongly impairs theta oscillations in the entorhinal-hippocampal circuits. Taken together, these findings demonstrate a major role of the MEC and MS in estimating distances to be traveled, and point to theta oscillations within the MEC as a neural mechanism responsible for the integration of information generated by linear self-displacements.

  3. Human anterolateral entorhinal cortex volumes are associated with cognitive decline in aging prior to clinical diagnosis.

    PubMed

    Olsen, Rosanna K; Yeung, Lok-Kin; Noly-Gandon, Alix; D'Angelo, Maria C; Kacollja, Arber; Smith, Victoria M; Ryan, Jennifer D; Barense, Morgan D

    2017-09-01

    We investigated whether older adults without subjective memory complaints, but who present with cognitive decline in the laboratory, demonstrate atrophy in medial temporal lobe (MTL) subregions associated with Alzheimer's disease. Forty community-dwelling older adults were categorized based on Montreal Cognitive Assessment (MoCA) performance. Total gray/white matter, cerebrospinal fluid, and white matter hyperintensity load were quantified from whole-brain T1-weighted and fluid-attenuated inversion recovery magnetic resonance imaging scans, whereas hippocampal subfields and MTL cortical subregion volumes (CA1, dentate gyrus/CA2/3, subiculum, anterolateral and posteromedial entorhinal, perirhinal, and parahippocampal cortices) were quantified using high-resolution T2-weighted scans. Cognitive status was evaluated using standard neuropsychological assessments. No significant differences were found in the whole-brain measures. However, MTL volumetry revealed that anterolateral entorhinal cortex (alERC) volume-the same region in which Alzheimer's pathology originates-was strongly associated with MoCA performance. This is the first study to demonstrate that alERC volume is related to cognitive decline in undiagnosed community-dwelling older adults. Copyright © 2017 Elsevier Inc. All rights reserved.

  4. Molecularly Defined Circuitry Reveals Input-Output Segregation in Deep Layers of the Medial Entorhinal Cortex.

    PubMed

    Sürmeli, Gülşen; Marcu, Daniel Cosmin; McClure, Christina; Garden, Derek L F; Pastoll, Hugh; Nolan, Matthew F

    2015-12-02

    Deep layers of the medial entorhinal cortex are considered to relay signals from the hippocampus to other brain structures, but pathways for routing of signals to and from the deep layers are not well established. Delineating these pathways is important for a circuit level understanding of spatial cognition and memory. We find that neurons in layers 5a and 5b have distinct molecular identities, defined by the transcription factors Etv1 and Ctip2, and divergent targets, with extensive intratelencephalic projections originating in layer 5a, but not 5b. This segregation of outputs is mirrored by the organization of glutamatergic input from stellate cells in layer 2 and from the hippocampus, with both preferentially targeting layer 5b over 5a. Our results suggest a molecular and anatomical organization of input-output computations in deep layers of the MEC, reveal precise translaminar microcircuitry, and identify molecularly defined pathways for spatial signals to influence computation in deep layers.

  5. Grid-layout and theta-modulation of layer 2 pyramidal neurons in medial entorhinal cortex.

    PubMed

    Ray, Saikat; Naumann, Robert; Burgalossi, Andrea; Tang, Qiusong; Schmidt, Helene; Brecht, Michael

    2014-02-21

    Little is known about how microcircuits are organized in layer 2 of the medial entorhinal cortex. We visualized principal cell microcircuits and determined cellular theta-rhythmicity in freely moving rats. Non-dentate-projecting, calbindin-positive pyramidal cells bundled dendrites together and formed patches arranged in a hexagonal grid aligned to layer 1 axons, parasubiculum, and cholinergic inputs. Calbindin-negative, dentate-gyrus-projecting stellate cells were distributed across layer 2 but avoided centers of calbindin-positive patches. Cholinergic drive sustained theta-rhythmicity, which was twofold stronger in pyramidal than in stellate neurons. Theta-rhythmicity was cell-type-specific but not distributed as expected from cell-intrinsic properties. Layer 2 divides into a weakly theta-locked stellate cell lattice and spatiotemporally highly organized pyramidal grid. It needs to be assessed how these two distinct principal cell networks contribute to grid cell activity.

  6. Subthreshold Membrane-Potential Resonances Shape Spike-Train Patterns in the Entorhinal Cortex

    PubMed Central

    Engel, T. A.; Schimansky-Geier, L.; Herz, A.V.M.; Schreiber, S.; Erchova, I.

    2008-01-01

    Many neurons exhibit subthreshold membrane-potential resonances, such that the largest voltage responses occur at preferred stimulation frequencies. Because subthreshold resonances are known to influence the rhythmic activity at the network level, it is vital to understand how they affect spike generation on the single-cell level. We therefore investigated both resonant and nonresonant neurons of rat entorhinal cortex. A minimal resonate-and-fire type model based on measured physiological parameters captures fundamental properties of neuronal firing statistics surprisingly well and helps to shed light on the mechanisms that shape spike patterns: 1) subthreshold resonance together with a spike-induced reset of subthreshold oscillations leads to spike clustering and 2) spike-induced dynamics influence the fine structure of interspike interval (ISI) distributions and are responsible for ISI correlations appearing at higher firing rates (≥3 Hz). Both mechanisms are likely to account for the specific discharge characteristics of various cell types. PMID:18450582

  7. Saccade direction encoding in the primate entorhinal cortex during visual exploration.

    PubMed

    Killian, Nathaniel J; Potter, Steve M; Buffalo, Elizabeth A

    2015-12-22

    We recently demonstrated that position in visual space is represented by grid cells in the primate entorhinal cortex (EC), suggesting that visual exploration of complex scenes in primates may employ signaling mechanisms similar to those used during exploration of physical space via movement in rodents. Here, we describe a group of saccade direction (SD) cells that encode eye movement information in the monkey EC during free-viewing of complex images. Significant saccade direction encoding was found in 20% of the cells recorded in the posterior EC. SD cells were generally broadly tuned and two largely separate populations of SD cells encoded future and previous saccade direction. Some properties of these cells resemble those of head-direction cells in rodent EC, suggesting that the same neural circuitry may be capable of performing homologous spatial computations under different exploratory contexts.

  8. Grid cells without theta oscillations in the entorhinal cortex of bats.

    PubMed

    Yartsev, Michael M; Witter, Menno P; Ulanovsky, Nachum

    2011-11-02

    Grid cells provide a neural representation of space, by discharging when an animal traverses through the vertices of a periodic hexagonal grid spanning the environment. Although grid cells have been characterized in detail in rats, the fundamental question of what neural dynamics give rise to the grid structure remains unresolved. Two competing classes of models were proposed: network models, based on attractor dynamics, and oscillatory interference models, which propose that interference between somatic and dendritic theta-band oscillations (4-10 Hz) in single neurons transforms a temporal oscillation into a spatially periodic grid. So far, these models could not be dissociated experimentally, because rodent grid cells always co-exist with continuous theta oscillations. Here we used a novel animal model, the Egyptian fruit bat, to refute the proposed causal link between grids and theta oscillations. On the basis of our previous finding from bat hippocampus, of spatially tuned place cells in the absence of continuous theta oscillations, we hypothesized that grid cells in bat medial entorhinal cortex might also exist without theta oscillations. Indeed, we found grid cells in bat medial entorhinal cortex that shared remarkable similarities to rodent grid cells. Notably, the grids existed in the absence of continuous theta-band oscillations, and with almost no theta modulation of grid-cell spiking--both of which are essential prerequisites of the oscillatory interference models. Our results provide a direct demonstration of grid cells in a non-rodent species. Furthermore, they strongly argue against a major class of computational models of grid cells.

  9. Entorhinal cortex structure and functional MRI response during an associative verbal memory task.

    PubMed

    Braskie, Meredith N; Small, Gary W; Bookheimer, Susan Y

    2009-12-01

    Entorhinal cortex (ERC) volume in adults with mild cognitive impairment has been shown to predict prodromal Alzheimer's disease (AD). Likewise, neuronal loss in ERC has been associated with AD, but not with normal aging. Because ERC is part of a major pathway modulating input to the hippocampus, structural changes there may result in changes to cognitive performance and functional brain activity during memory tasks. In 32 cognitively intact older adults, we examined the relationship between left ERC thickness and functional magnetic resonance imaging (fMRI) activity during an associative verbal memory task. This task has been shown previously to activate regions that are sensitive to aging and AD risk. ERC was manually defined on native space, high resolution, oblique coronal MRI scans. Subjects having thicker left ERC showed greater activation in anterior cingulate and medial frontal regions during memory retrieval, but not encoding. This result was independent of hippocampal volume. Anterior cingulate cortex is directly connected to ERC, and is, along with medial frontal cortex, implicated in error detection, which is impaired in AD. Our results suggest that in healthy older adults, processes that engage frontal regions during memory retrieval are related to ERC structure.

  10. Entorhinal cortex volume in older adults: reliability and validity considerations for three published measurement protocols.

    PubMed

    Price, C C; Wood, M F; Leonard, C M; Towler, S; Ward, J; Montijo, H; Kellison, I; Bowers, D; Monk, T; Newcomer, J C; Schmalfuss, I

    2010-09-01

    Measuring the entorhinal cortex (ERC) is challenging due to lateral border discrimination from the perirhinal cortex. From a sample of 39 nondemented older adults who completed volumetric image scans and verbal memory indices, we examined reliability and validity concerns for three ERC protocols with different lateral boundary guidelines (i.e., Goncharova, Dickerson, Stoub, & deToledo-Morrell, 2001; Honeycutt et al., 1998; Insausti et al., 1998). We used three novice raters to assess inter-rater reliability on a subset of scans (216 total ERCs), with the entire dataset measured by one rater with strong intra-rater reliability on each technique (234 total ERCs). We found moderate to strong inter-rater reliability for two techniques with consistent ERC lateral boundary endpoints (Goncharova, Honeycutt), with negligible to moderate reliability for the technique requiring consideration of collateral sulcal depth (Insausti). Left ERC and story memory associations were moderate and positive for two techniques designed to exclude the perirhinal cortex (Insausti, Goncharova), with the Insausti technique continuing to explain 10% of memory score variance after additionally controlling for depression symptom severity. Right ERC-story memory associations were nonexistent after excluding an outlier. Researchers are encouraged to consider challenges of rater training for ERC techniques and how lateral boundary endpoints may impact structure-function associations.

  11. Grid cells correlation structure suggests organized feedforward projections into superficial layers of the medial entorhinal cortex.

    PubMed

    Tocker, Gilad; Barak, Omri; Derdikman, Dori

    2015-12-01

    Navigation requires integration of external and internal inputs to form a representation of location. Part of this integration is considered to be carried out by the grid cells network in the medial entorhinal cortex (MEC). However, the structure of this neural network is unknown. To shed light on this structure, we measured noise correlations between 508 pairs of simultaneous previously recorded grid cells. We differentiated between pure grid and conjunctive cells (pure grid in Layers II, III, and VI vs. conjunctive in Layers III and V--only Layer III was bi-modal), and devised a new method to classify cell pairs as belonging/not-belonging to the same module. We found that pairs from the same module show significantly more correlations than pairs from different modules. The correlations between pure grid cells decreased in strength as their relative spatial phase increased. However, correlations were mostly at 0 time-lag, suggesting that the source of correlations was not only synaptic, but rather resulted mostly from common input. Given our measured correlations, the two functional groups of grid cells (pure vs. conjunctive), and the known disorganized recurrent connections within Layer II, we propose the following model: conjunctive cells in deep layers form an attractor network whose activity is governed by velocity-controlled signals. A second manifold in Layer II receives organized feedforward projections from the deep layers, giving rise to pure grid cells. Numerical simulations indicate that organized projections induce such correlations as we measure in superficial layers. Our results provide new evidence for the functional anatomy of the entorhinal circuit-suggesting that strong phase-organized feedforward projections support grid fields in the superficial layers. © 2015 Wiley Periodicals, Inc.

  12. Rebound spiking in layer II medial entorhinal cortex stellate cells: Possible mechanism of grid cell function.

    PubMed

    Shay, Christopher F; Ferrante, Michele; Chapman, G William; Hasselmo, Michael E

    2016-03-01

    Rebound spiking properties of medial entorhinal cortex (mEC) stellate cells induced by inhibition may underlie their functional properties in awake behaving rats, including the temporal phase separation of distinct grid cells and differences in grid cell firing properties. We investigated rebound spiking properties using whole cell patch recording in entorhinal slices, holding cells near spiking threshold and delivering sinusoidal inputs, superimposed with realistic inhibitory synaptic inputs to test the capacity of cells to selectively respond to specific phases of inhibitory input. Stellate cells showed a specific phase range of hyperpolarizing inputs that elicited spiking, but non-stellate cells did not show phase specificity. In both cell types, the phase range of spiking output occurred between the peak and subsequent descending zero crossing of the sinusoid. The phases of inhibitory inputs that induced spikes shifted earlier as the baseline sinusoid frequency increased, while spiking output shifted to later phases. Increases in magnitude of the inhibitory inputs shifted the spiking output to earlier phases. Pharmacological blockade of h-current abolished the phase selectivity of hyperpolarizing inputs eliciting spikes. A network computational model using cells possessing similar rebound properties as found in vitro produces spatially periodic firing properties resembling grid cell firing when a simulated animal moves along a linear track. These results suggest that the ability of mEC stellate cells to fire rebound spikes in response to a specific range of phases of inhibition could support complex attractor dynamics that provide completion and separation to maintain spiking activity of specific grid cell populations.

  13. Intrinsic electrophysiological properties of entorhinal cortex stellate cells and their contribution to grid cell firing fields

    PubMed Central

    Pastoll, Hugh; Ramsden, Helen L.; Nolan, Matthew F.

    2012-01-01

    The medial entorhinal cortex (MEC) is an increasingly important focus for investigation of mechanisms for spatial representation. Grid cells found in layer II of the MEC are likely to be stellate cells, which form a major projection to the dentate gyrus. Entorhinal stellate cells are distinguished by distinct intrinsic electrophysiological properties, but how these properties contribute to representation of space is not yet clear. Here, we review the ionic conductances, synaptic, and excitable properties of stellate cells, and examine their implications for models of grid firing fields. We discuss why existing data are inconsistent with models of grid fields that require stellate cells to generate periodic oscillations. An alternative possibility is that the intrinsic electrophysiological properties of stellate cells are tuned specifically to control integration of synaptic input. We highlight recent evidence that the dorsal-ventral organization of synaptic integration by stellate cells, through differences in currents mediated by HCN and leak potassium channels, influences the corresponding organization of grid fields. Because accurate cellular data will be important for distinguishing mechanisms for generation of grid fields, we introduce new data comparing properties measured with whole-cell and perforated patch-clamp recordings. We find that clustered patterns of action potential firing and the action potential after-hyperpolarization (AHP) are particularly sensitive to recording condition. Nevertheless, with both methods, these properties, resting membrane properties and resonance follow a dorsal-ventral organization. Further investigation of the molecular basis for synaptic integration by stellate cells will be important for understanding mechanisms for generation of grid fields. PMID:22536175

  14. Rebound spiking in layer II medial entorhinal cortex stellate cells: Possible mechanism of grid cell function

    PubMed Central

    Shay, Christopher F.; Ferrante, Michele; Chapman, G. William; Hasselmo, Michael E.

    2015-01-01

    Rebound spiking properties of medial entorhinal cortex (mEC) stellate cells induced by inhibition may underlie their functional properties in awake behaving rats, including the temporal phase separation of distinct grid cells and differences in grid cell firing properties. We investigated rebound spiking properties using whole cell patch recording in entorhinal slices, holding cells near spiking threshold and delivering sinusoidal inputs, superimposed with realistic inhibitory synaptic inputs to test the capacity of cells to selectively respond to specific phases of inhibitory input. Stellate cells showed a specific phase range of hyperpolarizing inputs that elicited spiking, but non-stellate cells did not show phase specificity. In both cell types, the phase range of spiking output occurred between the peak and subsequent descending zero crossing of the sinusoid. The phases of inhibitory inputs that induced spikes shifted earlier as the baseline sinusoid frequency increased, while spiking output shifted to later phases. Increases in magnitude of the inhibitory inputs shifted the spiking output to earlier phases. Pharmacological blockade of h-current abolished the phase selectivity of hyperpolarizing inputs eliciting spikes. A network computational model using cells possessing similar rebound properties as found in vitro produces spatially periodic firing properties resembling grid cell firing when a simulated animal moves along a linear track. These results suggest that the ability of mEC stellate cells to fire rebound spikes in response to a specific range of phases of inhibition could support complex attractor dynamics that provide completion and separation to maintain spiking activity of specific grid cell populations. PMID:26385258

  15. Functional correlates of the lateral and medial entorhinal cortex: objects, path integration and local-global reference frames.

    PubMed

    Knierim, James J; Neunuebel, Joshua P; Deshmukh, Sachin S

    2014-02-05

    The hippocampus receives its major cortical input from the medial entorhinal cortex (MEC) and the lateral entorhinal cortex (LEC). It is commonly believed that the MEC provides spatial input to the hippocampus, whereas the LEC provides non-spatial input. We review new data which suggest that this simple dichotomy between 'where' versus 'what' needs revision. We propose a refinement of this model, which is more complex than the simple spatial-non-spatial dichotomy. MEC is proposed to be involved in path integration computations based on a global frame of reference, primarily using internally generated, self-motion cues and external input about environmental boundaries and scenes; it provides the hippocampus with a coordinate system that underlies the spatial context of an experience. LEC is proposed to process information about individual items and locations based on a local frame of reference, primarily using external sensory input; it provides the hippocampus with information about the content of an experience.

  16. Laminar organization of epileptiform discharges in the rat entorhinal cortex in vitro

    PubMed Central

    Lopantsev, Valeri; Avoli, Massimo

    1998-01-01

    Interictal and ictal epileptiform discharges induced by 4-aminopyridine (4AP, 50 μM) were studied in the rat lateral entorhinal cortex with field potential and intracellular recordings in an in vitro slice preparation. Both types of discharge disappeared in layer II, but continued to occur in layers IV-VI after a knife cut separation was made at approximately 600 μm from the pia (n = 4 slices). Interictal depolarizations recorded in layer IV-VI cells (amplitude, 29.4 ± 8.6 mV; duration, 386 ± 177.4 ms, means ± s.d.; n = 17) were capped by action potential bursts, while smaller interictal depolarizations in layer II cells (amplitude, 11.7 ± 5.8 mV; duration, 192.6 ± 47.9 ms; n = 10) were associated with single action potentials and were terminated by a hyperpolarization. Ictal discharges were initiated by an interictal discharge; they were characterized by a depolarization of 31.5 ± 6.2 mV (n = 12) in layer IV-VI and 11.6 ± 3.5 mV (n = 7) in layer II neurones. Slow, presumptive Ca2+-mediated spikes occurred in layer II (n = 4) and IV-VI (n = 6) cells loaded with the Na+ channel blocker QX-314 (50 mM). These events were synchronized with population spikes during interictal and ictal discharges, and were abolished by Ni2+ (1 mM, n = 4 cells) along with the 4AP-induced synchronous activity. The N-methyl-D-aspartate (NMDA) receptor antagonist 3,3-(2-carboxypiperazine-4-yl)-propyl-1-phosphonate (CPP, 10 μM) abolished ictal discharges and reduced interictal depolarizations in layer IV-VI neurones (n = 4). The non-NMDA receptor antagonist 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX, 10 μM) abolished both interictal and ictal activity (n = 4 cells). These findings provide evidence for a role played by NMDA-mediated mechanisms in the generation of epileptiform discharges in the entorhinal cortex. Lack of an NMDA-mediated component along with presence of inhibition in layer II neurones results in attenuation of epileptiform activity at this site. Moreover Ca2

  17. Parallel processing of information about location in the amygdala, entorhinal cortex and hippocampus.

    PubMed

    Gaskin, Stephane; White, Norman M

    2013-11-01

    The conditioned cue preference paradigm was used to study how rats use extra-maze cues to discriminate between 2 adjacent arms on an 8-arm radial maze, a situation in which most of the same cues can be seen from both arms but only one arm contains food. Since the food-restricted rats eat while passively confined on the food-paired arm no responses are reinforced, so the discrimination is due to Pavlovian stimulus-reward (or outcome) learning. Consistent with other evidence that rats must move around in an environment to acquire a spatial map, we found that learning the adjacent arms CCP (ACCP) required a minimum amount of active exploration of the maze with no reinforcers present prior to passive pairing of the extra-maze cues with the food reinforcer, an instance of latent learning. Temporary inactivation of the hippocampus during the pre-exposure sessions had no effect on ACCP learning, confirming other evidence that the hippocampus is not involved in latent learning. A series of experiments indentified a circuit involving fimbria-fornix and dorsal entorhinal cortex as the neural basis of latent learning in this situation. In contrast, temporary inactivation of the entorhinal cortex or hippocampus during passive training or during testing blocked ACCP learning and expression, respectively, suggesting that these two structures co-operate in using spatial information to learn the location of food on the maze during passive pairing and to express this combined information during testing. In parallel with these processes we found that the amygdala processes information leading to an equal tendency to enter both adjacent arms (even though only one was paired with food) suggesting that the stimulus information available to this structure is not sufficiently precise to discriminate between the ambiguous cues visible from the adjacent arms. Expression of the ACCP in normal rats depends on hippocampus-based learning to avoid the unpaired arm which competes with the

  18. Impaired expression of GABA transporters in the human Alzheimer's disease hippocampus, subiculum, entorhinal cortex and superior temporal gyrus.

    PubMed

    Fuhrer, Tessa E; Palpagama, Thulani H; Waldvogel, Henry J; Synek, Beth J L; Turner, Clinton; Faull, Richard L; Kwakowsky, Andrea

    2017-05-20

    Gamma-aminobutyric acid (GABA) is the main inhibitory neurotransmitter in the brain and plays an important role in regulating neuronal excitability. GABA reuptake from the synapse is dependent on specific transporters - mainly GAT-1, GAT-3 and BGT-1 (GATs). This study is the first to show alterations in the expression of the GATs in the Alzheimer's disease (AD) hippocampus, entorhinal cortex and superior temporal gyrus. We found a significant increase in BGT-1 expression associated with AD in all layers of the dentate gyrus, in the stratum oriens of the CA2 and CA3 and the superior temporal gyrus. In AD there was a significant decrease in GAT-1 expression in the entorhinal cortex and superior temporal gyrus. We also found a significant decrease in GAT-3 immunoreactivity in the stratum pyramidale of the CA1 and CA3, the subiculum and entorhinal cortex. These observations indicate that the expression of the GATs shows brain-region- and layer-specific alterations in AD, suggesting a complex activation pattern of different GATs during the course of the disease. Copyright © 2017 IBRO. Published by Elsevier Ltd. All rights reserved.

  19. Retrograde and anterograde memory following selective damage to the dorsolateral entorhinal cortex.

    PubMed

    Gervais, Nicole J; Barrett-Bernstein, Meagan; Sutherland, Robert J; Mumby, Dave G

    2014-12-01

    Anatomical and electrophysiological evidence suggest the dorsolateral entorhinal cortex (DLEC) is involved in processing spatial information, but there is currently no consensus on whether its functions are necessary for normal spatial learning and memory. The present study examined the effects of excitotoxic lesions of the DLEC on retrograde and anterograde memory on two tests of allocentric spatial learning: a hidden fixed-platform watermaze task, and a novelty-preference-based dry-maze test. Deficits were observed on both tests when training occurred prior to but not following n-methyl d-aspartate (NMDA) lesions of DLEC, suggesting retrograde memory impairment in the absence of anterograde impairments for the same information. The retrograde memory impairments were temporally-graded; rats that received DLEC lesions 1-3 days following training displayed deficits, while those that received lesions 7-10 days following training performed like a control group that received sham surgery. The deficits were not attenuated by co-infusion of tetrodotoxin, suggesting they are not due to disruption of neural processing in structures efferent to the DLEC, such as the hippocampus. The present findings provide evidence that the DLEC is involved in the consolidation of allocentric spatial information.

  20. Entorhinal cortex contribution to contextual fear conditioning extinction and reconsolidation in rats.

    PubMed

    Baldi, Elisabetta; Bucherelli, Corrado

    2014-04-01

    During contextual fear conditioning a rat learns a temporal contiguity association between the exposition to a previously neutral context (CS) and an aversive unconditioned stimulus (US) as a footshock. This condition determines in the rat the freezing reaction during the subsequent re-exposition to the context. Potentially the re-exposition without US presentation initiates two opposing and competing processes: reconsolidation and extinction. Reconsolidation process re-stabilizes and strengthens the original memory and it is initiated by a brief re-exposure to context. Instead the extinction process leads to the decrease of the expression of the original memory and it is triggered by prolonged re-exposure to the context. Here we analyzed the entorhinal cortex (ENT) participation in contextual fear conditioning reconsolidation and extinction. The rats were trained in contextual fear conditioning and 24h later they were subjected either to a brief (2 min) reactivation session or to a prolonged (120 min) re-exposition to context to induce extinction of the contextual fear memory. Immediately after the reactivation or the extinction session, the animals were submitted to bilateral ENT TTX inactivation. Memory retention was assessed as conditioned freezing duration measured 72 h after TTX administration. The results showed that ENT inactivation both after reactivation and extinction session was followed by contextual freezing retention impairment. Thus, the present findings point out that ENT is involved in contextual fear memory reconsolidation and extinction. This neural structure might be part of parallel circuits underlying two phases of contextual fear memory processing.

  1. Subthreshold Na+-dependent theta-like rhythmicity in stellate cells of entorhinal cortex layer II

    NASA Astrophysics Data System (ADS)

    Alonso, Angel; Llinás, Rodolfo R.

    1989-11-01

    THE oscillation of membrane potential in mammalian central neurons is of interest because it relates to the role of oscillations in brain function. It has been proposed that the entorhinal cortex (EC), particularly the stellate cells of layer II (ECIIscs), plays an important part in the genesis of the theta rhythm1-3. These neurons occupy a key position in the neocortex-hippocampus-neocortex circuit, a crucial crossroad in memory functions4,5. Neuronal oscillations typically rely on the activation of voltage-dependent Ca2+ conductances and the Ca2+-dependent K+ conductance that usually follows6,7, as seen in other limbic subcortical structures generating theta rhymicity8-10. Here we report, however, that similar oscillations are generated in ECIIscs by a Na+ conductance. The finding of a subthreshold, voltage-gated, Na+-dependent rhythmic membrane oscillation in mammalian neurons indicates that rhythmicity in heterogeneous neuronal networks may be supported by different sets of intrinsic ionic mechanisms in each of the neuronal elements involved.

  2. Nonlinear properties of medial entorhinal cortex neurons reveal frequency selectivity during multi-sinusoidal stimulation.

    PubMed

    Magnani, Christophe; Economo, Michael N; White, John A; Moore, Lee E

    2014-01-01

    The neurons in layer II of the medial entorhinal cortex are part of the grid cell network involved in the representation of space. Many of these neurons are likely to be stellate cells with specific oscillatory and firing properties important for their function. A fundamental understanding of the nonlinear basis of these oscillatory properties is critical for the development of theories of grid cell firing. In order to evaluate the behavior of stellate neurons, measurements of their quadratic responses were used to estimate a second order Volterra kernel. This paper uses an operator theory, termed quadratic sinusoidal analysis (QSA), which quantitatively determines that the quadratic response accounts for a major part of the nonlinearity observed at membrane potential levels characteristic of normal synaptic events. Practically, neurons were probed with multi-sinusoidal stimulations to determine a Hermitian operator that captures the quadratic function in the frequency domain. We have shown that the frequency content of the stimulation plays an important role in the characteristics of the nonlinear response, which can distort the linear response as well. Stimulations with enhanced low frequency amplitudes evoked a different nonlinear response than broadband profiles. The nonlinear analysis was also applied to spike frequencies and it was shown that the nonlinear response of subthreshold membrane potential at resonance frequencies near the threshold is similar to the nonlinear response of spike trains.

  3. A distinct entorhinal cortex to hippocampal CA1 direct circuit for olfactory associative learning.

    PubMed

    Li, Yiding; Xu, Jiamin; Liu, Yafeng; Zhu, Jia; Liu, Nan; Zeng, Wenbo; Huang, Ning; Rasch, Malte J; Jiang, Haifei; Gu, Xiang; Li, Xiang; Luo, Minhua; Li, Chengyu; Teng, Junlin; Chen, Jianguo; Zeng, Shaoqun; Lin, Longnian; Zhang, Xiaohui

    2017-04-01

    Lateral and medial parts of entorhinal cortex (EC) convey nonspatial 'what' and spatial 'where' information, respectively, into hippocampal CA1, via both the indirect EC layer 2→ hippocampal dentate gyrus→CA3→CA1 and the direct EC layer 3→CA1 paths. However, it remains elusive how the direct path transfers distinct information and contributes to hippocampal learning functions. Here we report that lateral EC projection neurons selectively form direct excitatory synapses onto a subpopulation of morphologically complex, calbindin-expressing pyramidal cells (PCs) in the dorsal CA1 (dCA1), while medial EC neurons uniformly innervate all dCA1 PCs. Optogenetically inactivating the distinct lateral EC-dCA1 connections or the postsynaptic dCA1 calbindin-expressing PC activity slows olfactory associative learning. Moreover, optetrode recordings reveal that dCA1 calbindin-expressing PCs develop more selective spiking responses to odor cues during learning. Thus, our results identify a direct lateral EC→dCA1 circuit that is required for olfactory associative learning.

  4. GABAergic Projections from the Medial Septum Selectively Inhibit Interneurons in the Medial Entorhinal Cortex

    PubMed Central

    Gonzalez-Sulser, Alfredo; Parthier, Daniel; Candela, Antonio; McClure, Christina; Pastoll, Hugh; Garden, Derek; Sürmeli, Gülşen

    2014-01-01

    The medial septum (MS) is required for theta rhythmic oscillations and grid cell firing in the medial entorhinal cortex (MEC). While GABAergic, glutamatergic, and cholinergic neurons project from the MS to the MEC, their synaptic targets are unknown. To investigate whether MS neurons innervate specific layers and cell types in the MEC, we expressed channelrhodopsin-2 in mouse MS neurons and used patch-clamp recording in brain slices to determine the response to light activation of identified cells in the MEC. Following activation of MS axons, we observed fast monosynaptic GABAergic IPSPs in the majority (>60%) of fast-spiking (FS) and low-threshold-spiking (LTS) interneurons in all layers of the MEC, but in only 1.5% of nonstellate principal cells (NSPCs) and in no stellate cells. We also observed fast glutamatergic responses to MS activation in a minority (<5%) of NSPCs, FS, and LTS interneurons. During stimulation of MS inputs at theta frequency (10 Hz), the amplitude of GABAergic IPSPs was maintained, and spike output from LTS and FS interneurons was entrained at low (25–60 Hz) and high (60–180 Hz) gamma frequencies, respectively. By demonstrating cell type-specific targeting of the GABAergic projection from the MS to the MEC, our results support the idea that the MS controls theta frequency activity in the MEC through coordination of inhibitory circuits. PMID:25505326

  5. Preserved number of entorhinal cortex layer II neurons in aged macaque monkeys

    NASA Technical Reports Server (NTRS)

    Gazzaley, A. H.; Thakker, M. M.; Hof, P. R.; Morrison, J. H.; Bloom, F. E. (Principal Investigator)

    1997-01-01

    The perforant path, which consists of the projection from the layer II neurons of the entorhinal cortex to the outer molecular layer of the dentate gyrus, is a critical circuit involved in learning and memory formation. Accordingly, disturbances in this circuit may contribute to age-related cognitive deficits. In a previous study, we demonstrated a decrease in N-methyl-D-aspartate receptor subunit 1 immunofluorescence intensity in the outer molecular layer of aged macaque monkeys. In this study, we used the optical fractionator, a stereological method, to determine if a loss of layer II neurons occurred in the same animals in which the N-methyl-D-aspartate receptor subunit 1 alteration was observed. Our results revealed no significant differences in the number of layer II neurons between juvenile, young adult, and aged macaque monkeys. These results suggest that the circuit-specific decrease in N-methyl-D-aspartate receptor subunit 1 reported previously occurs in the absence of structural compromise of the perforant path, and thus may be linked to an age-related change in the physiological properties of this circuit.

  6. Synaptic Conductances during Interictal Discharges in Pyramidal Neurons of Rat Entorhinal Cortex

    PubMed Central

    Amakhin, Dmitry V.; Ergina, Julia L.; Chizhov, Anton V.; Zaitsev, Aleksey V.

    2016-01-01

    In epilepsy, the balance of excitation and inhibition underlying the basis of neural network activity shifts, resulting in neuronal network hyperexcitability and recurrent seizure-associated discharges. Mechanisms involved in ictal and interictal events are not fully understood, in particular, because of controversial data regarding the dynamics of excitatory and inhibitory synaptic conductances. In the present study, we estimated AMPAR-, NMDAR-, and GABAA R-mediated conductances during two distinct types of interictal discharge (IID) in pyramidal neurons of rat entorhinal cortex in cortico-hippocampal slices. Repetitively emerging seizure-like events and IIDs were recorded in high extracellular potassium, 4-aminopyridine, and reduced magnesium-containing solution. An original procedure for estimating synaptic conductance during IIDs was based on the differences among the current-voltage characteristics of the synaptic components. The synaptic conductance dynamics obtained revealed that the first type of IID is determined by activity of GABAA R channels with depolarized reversal potential. The second type of IID is determined by the interplay between excitation and inhibition, with early AMPAR and prolonged depolarized GABAA R and NMDAR-mediated components. The study then validated the contribution of these components to IIDs by intracellular pharmacological isolation. These data provide new insights into the mechanisms of seizures generation, development, and cessation. PMID:27790093

  7. A model for the differentiation between grid and conjunctive units in medial entorhinal cortex.

    PubMed

    Si, Bailu; Treves, Alessandro

    2013-12-01

    The multiple layers of medial entorhinal cortex (mEC) contain cells that differ in selectivity, connectivity, and cellular properties. Grid cells in layer II and in the deeper layers express triangular grid patterns in the environment. The firing rate of the conjunctive cells found in layer III and below, on the other hand, show grid-by-head direction tuning. In this study, we model the differentiation between grid and conjunctive cells in a network with self-organized connections. Arranged into distinct "layers", the model grid units and conjunctive units develop, with a similar time course, grid fields resulting from firing rate adaptation and competitive learning. Grid alignment in both layers is delayed with respect to the formation of triangular grids. A common grid orientation among conjunctive units is produced, in the model, by head-direction modulated collateral interactions, while the grids of grid units inherit the same orientation through connections from conjunctive units. Grid units as well as conjunctive units share a similar spacing but show a random distribution of spatial phases. Grid units however carry more spatial information than conjunctive units, thus providing better inputs for the hippocampus to form spatial memories. Copyright © 2013 Wiley Periodicals, Inc.

  8. Dopamine suppresses persistent network activity via D1-like dopamine receptors in rat medial entorhinal cortex

    PubMed Central

    Mayne, Elizabeth W; Craig, Michael T; McBain, Chris J; Paulsen, Ole

    2013-01-01

    Cortical networks display persistent activity in the form of periods of sustained synchronous depolarizations (‘UP states’) punctuated by periods of relative hyperpolarization (‘DOWN states’), which together form the slow oscillation. UP states are known to be synaptically generated and are sustained by a dynamic balance of excitation and inhibition, with fast ionotropic glutamatergic excitatory and GABAergic inhibitory conductances increasing during the UP state. Previously, work from our group demonstrated that slow metabotropic GABA receptors also play an important role in terminating the UP state, but the effects of other neuromodulators on this network phenomenon have received little attention. Given that persistent activity is a neural correlate of working memory and that signalling through dopamine receptors has been shown to be critical for working memory tasks, we examined whether dopaminergic neurotransmission affected the slow oscillation. Here, using an in vitro model of the slow oscillation in rat medial entorhinal cortex, we showed that dopamine strongly and reversibly suppressed cortical UP states. We showed that this effect was mediated through D1-like and not D2-like dopamine receptors, and we found no evidence that tonic dopaminergic transmission affected UP states in our model. PMID:23336973

  9. Parvalbumin interneurons provide grid cell-driven recurrent inhibition in the medial entorhinal cortex.

    PubMed

    Buetfering, Christina; Allen, Kevin; Monyer, Hannah

    2014-05-01

    Grid cells in the medial entorhinal cortex (MEC) generate metric spatial representations. Recent attractor-network models suggest an essential role for GABAergic interneurons in the emergence of the grid-cell firing pattern through recurrent inhibition dependent on grid-cell phase. To test this hypothesis, we studied identified parvalbumin-expressing (PV(+)) interneurons that are the most likely candidate for providing this recurrent inhibition onto grid cells. Using optogenetics and tetrode recordings in mice, we found that PV(+) interneurons exhibited high firing rates, low spatial sparsity and no spatial periodicity. PV(+) interneurons inhibited all functionally defined cell types in the MEC and were in turn recruited preferentially by grid cells. To our surprise, we found that individual PV(+) interneurons received input from grid cells with various phases, which most likely accounts for the broadly tuned spatial firing activity of PV(+) interneurons. Our data argue against the notion that PV(+) interneurons provide phase-dependent recurrent inhibition and challenge recent attractor-network models of grid cells.

  10. Direct Medial Entorhinal Cortex Input to Hippocampal CA1 Is Crucial for Extended Quiet Awake Replay.

    PubMed

    Yamamoto, Jun; Tonegawa, Susumu

    2017-09-27

    Hippocampal replays have been demonstrated to play a crucial role in memory. Chains of ripples (ripple bursts) in CA1 have been reported to co-occur with long-range place cell sequence replays during the quiet awake state, but roles of neural inputs to CA1 in ripple bursts and replays are unknown. Here we show that ripple bursts in CA1 and medial entorhinal cortex (MEC) are temporally associated. An inhibition of MECIII input to CA1 during quiet awake reduced ripple bursts in CA1 and restricted the spatial coverage of replays to a shorter distance corresponding to single ripple events. The reduction did not occur with MECIII input inhibition during slow-wave sleep. Inhibition of CA3 activity suppressed ripples and replays in CA1 regardless of behavioral state. Thus, MECIII input to CA1 is crucial for ripple bursts and long-range replays specifically in quiet awake, whereas CA3 input is essential for both, regardless of behavioral state. Copyright © 2017 Elsevier Inc. All rights reserved.

  11. GABAergic projections from the medial septum selectively inhibit interneurons in the medial entorhinal cortex.

    PubMed

    Gonzalez-Sulser, Alfredo; Parthier, Daniel; Candela, Antonio; McClure, Christina; Pastoll, Hugh; Garden, Derek; Sürmeli, Gülşen; Nolan, Matthew F

    2014-12-10

    The medial septum (MS) is required for theta rhythmic oscillations and grid cell firing in the medial entorhinal cortex (MEC). While GABAergic, glutamatergic, and cholinergic neurons project from the MS to the MEC, their synaptic targets are unknown. To investigate whether MS neurons innervate specific layers and cell types in the MEC, we expressed channelrhodopsin-2 in mouse MS neurons and used patch-clamp recording in brain slices to determine the response to light activation of identified cells in the MEC. Following activation of MS axons, we observed fast monosynaptic GABAergic IPSPs in the majority (>60%) of fast-spiking (FS) and low-threshold-spiking (LTS) interneurons in all layers of the MEC, but in only 1.5% of nonstellate principal cells (NSPCs) and in no stellate cells. We also observed fast glutamatergic responses to MS activation in a minority (<5%) of NSPCs, FS, and LTS interneurons. During stimulation of MS inputs at theta frequency (10 Hz), the amplitude of GABAergic IPSPs was maintained, and spike output from LTS and FS interneurons was entrained at low (25-60 Hz) and high (60-180 Hz) gamma frequencies, respectively. By demonstrating cell type-specific targeting of the GABAergic projection from the MS to the MEC, our results support the idea that the MS controls theta frequency activity in the MEC through coordination of inhibitory circuits.

  12. Exposure to extremely low frequency electromagnetic fields alters the calcium dynamics of cultured entorhinal cortex neurons.

    PubMed

    Luo, Fen-Lan; Yang, Nian; He, Chao; Li, Hong-Li; Li, Chao; Chen, Fang; Xiong, Jia-Xiang; Hu, Zhi-An; Zhang, Jun

    2014-11-01

    Previous studies have revealed that extremely low frequency electromagnetic field (ELF-EMF) exposure affects neuronal dendritic spine density and NMDAR and AMPAR subunit expressions in the entorhinal cortex (EC). Although calcium signaling has a critical role in control of EC neuronal functions, however, it is still unclear whether the ELF-EMF exposure affects the EC neuronal calcium homeostasis. In the present study, using whole-cell recording and calcium imaging, we record the whole-cell inward currents that contain the voltage-gated calcium currents and show that ELF-EMF (50Hz, 1mT or 3mT, lasting 24h) exposure does not influence these currents. Next, we specifically isolate the high-voltage activated (HVA) and low-voltage activated (LVA) calcium channels-induced currents. Similarly, the activation and inactivation characteristics of these membrane calcium channels are also not influenced by ELF-EMF. Importantly, ELF-EMF exposure reduces the maximum amplitude of the high-K(+)-evoked calcium elevation in EC neurons, which is abolished by thapsigargin, a Ca(2+) ATPase inhibitor, to empty the intracellular calcium stores of EC neurons. Together, these findings indicate that ELF-EMF exposure specifically influences the intracellular calcium dynamics of cultural EC neurons via a calcium channel-independent mechanism.

  13. Alteration of transcriptional networks in the entorhinal cortex after maternal immune activation and adolescent cannabinoid exposure.

    PubMed

    Hollins, Sharon L; Zavitsanou, Katerina; Walker, Frederick Rohan; Cairns, Murray J

    2016-08-01

    Maternal immune activation (MIA) and adolescent cannabinoid exposure (ACE) have both been identified as major environmental risk factors for schizophrenia. We examined the effects of these two risk factors alone, and in combination, on gene expression during late adolescence. Pregnant rats were exposed to the viral infection mimic polyriboinosinic-polyribocytidylic acid (poly I:C) on gestational day (GD) 15. Adolescent offspring received daily injections of the cannabinoid HU210 for 14days starting on postnatal day (PND) 35. Gene expression was examined in the left entorhinal cortex (EC) using mRNA microarrays. We found prenatal treatment with poly I:C alone, or HU210 alone, produced relatively minor changes in gene expression. However, following combined treatments, offspring displayed significant changes in transcription. This dramatic and persistent alteration of transcriptional networks enriched with genes involved in neurotransmission, cellular signalling and schizophrenia, was associated with a corresponding perturbation in the expression of small non-coding microRNA (miRNA). These results suggest that a combination of environmental exposures during development leads to significant genomic remodeling that disrupts maturation of the EC and its associated circuitry with important implications as the potential antecedents of memory and learning deficits in schizophrenia and other neuropsychiatric disorders.

  14. The entorhinal cortex is involved in conditioned odor and context aversions

    PubMed Central

    Ferry, Barbara; Herbeaux, Karine; Javelot, Hervé; Majchrzak, Monique

    2015-01-01

    In a natural environment, avoidance of a particular food source is mostly determined by a previous intake experience during which sensory stimuli such as food odor, become aversive through a simple associative conditioned learning. Conditioned odor aversion learning (COA) is a food conditioning paradigm that results from the association between a tasteless scented solution (conditioned stimulus, CS) and a gastric malaise (unconditioned stimulus, US) that followed its ingestion. In the present experimental conditions, acquisition of COA also led to acquisition of aversion toward the context in which the CS was presented (conditioned context aversion, CCA). Previous data have shown that the entorhinal cortex (EC) is involved in the memory processes underlying COA acquisition and context fear conditioning, but whether EC lesion modulates CCA acquisition has never be investigated. To this aim, male Long-Evans rats with bilateral EC lesion received CS-US pairings in a particular context with different interstimulus intervals (ISI). The results showed that the establishment of COA with long ISI obtained in EC-lesioned rats is associated with altered CCA learning. Since ISI has been suggested to be the determining factor in the odor- and context-US association, our results show that the EC is involved in the processes that control both associations relative to ISI duration. PMID:26483624

  15. Laminar activity in the hippocampus and entorhinal cortex related to novelty and episodic encoding

    PubMed Central

    Maass, Anne; Schütze, Hartmut; Speck, Oliver; Yonelinas, Andrew; Tempelmann, Claus; Heinze, Hans-Jochen; Berron, David; Cardenas-Blanco, Arturo; Brodersen, Kay H.; Enno Stephan, Klaas; Düzel, Emrah

    2014-01-01

    The ability to form long-term memories for novel events depends on information processing within the hippocampus (HC) and entorhinal cortex (EC). The HC–EC circuitry shows a quantitative segregation of anatomical directionality into different neuronal layers. Whereas superficial EC layers mainly project to dentate gyrus (DG), CA3 and apical CA1 layers, HC output is primarily sent from pyramidal CA1 layers and subiculum to deep EC layers. Here we utilize this directionality information by measuring encoding activity within HC/EC subregions with 7 T high resolution functional magnetic resonance imaging (fMRI). Multivariate Bayes decoding within HC/EC subregions shows that processing of novel information most strongly engages the input structures (superficial EC and DG/CA2–3), whereas subsequent memory is more dependent on activation of output regions (deep EC and pyramidal CA1). This suggests that while novelty processing is strongly related to HC–EC input pathways, the memory fate of a novel stimulus depends more on HC–EC output. PMID:25424131

  16. A cholinergic-dependent role for the entorhinal cortex in trace fear conditioning.

    PubMed

    Esclassan, Frederic; Coutureau, Etienne; Di Scala, Georges; Marchand, Alain R

    2009-06-24

    Trace conditioning is considered a model of higher cognitive involvement in simple associative tasks. Studies of trace conditioning have shown that cortical areas and the hippocampal formation are required to associate events that occur at different times. However, the mechanisms that bridge the trace interval during the acquisition of trace conditioning remain unknown. In four experiments with fear conditioning in rats, we explored the involvement of the entorhinal cortex (EC) in the acquisition of fear under a trace-30 s protocol. We first determined that pretraining neurotoxic lesions of the EC selectively impaired trace-, but not delay-conditioned fear as evaluated by freezing behavior. A local cholinergic deafferentation of the EC using 192-IgG-saporin did not replicate this deficit, presumably because cholinergic interneurons were spared by the toxin. However, pretraining local blockade of EC muscarinic receptors with the M1 antagonist pirenzepine yielded a specific and dose-dependent deficit in trace-conditioned responses. The same microinjections performed after conditioning were without effect on trace fear responses. These effects of blocking M1 receptors are consistent with the notion that conditioned stimulus (CS)-elicited, acetylcholine-dependent persistent activities in the EC are needed to maintain a representation of a tone CS across the trace interval during the acquisition of trace conditioning. This function of the EC is consistent with recent views of this region as a short-term stimulus buffer.

  17. Field repetition and local mapping in the hippocampus and medial entorhinal cortex.

    PubMed

    Grieves, Roddy M; Duvelle, Éléonore; Wood, Emma R; Dudchenko, Paul Anthony

    2017-08-16

    Hippocampal place cells support spatial cognition and are thought to form the neural substrate of a global 'cognitive map'. A widely held view is that parts of the hippocampus also underlie the ability to separate patterns, or to provide different neural codes for distinct environments. However, a number of studies have shown that in environments composed of multiple, repeating compartments, place cells and other spatially modulated neurons show the same activity in each local area. This repetition of firing fields may reflect pattern completion, and may make it difficult for animals to distinguish similar local environments. In this review we will (a) highlight some of the navigation difficulties encountered by humans in repetitive environments, (b) summarise literature demonstrating that place and grid cells represent local and not global space, and (c) attempt to explain the origin of these phenomena. We argue that the repetition of firing fields can be a useful tool for understanding of the relationship between grid cells in the entorhinal cortex and place cells in the hippocampus, the spatial inputs shared by these cells, and the propagation of spatially-related signals through these structures. Copyright © 2016, Journal of Neurophysiology.

  18. [Comparative study of bilateral lesions in the entorhinal cortex and in the fimbria fornix].

    PubMed

    Almaguer-Melian, W; Vallejo, A; Ramírez, M; Capdevila, V; Rosillo-Martí, J C; Bergado-Rosado, J A

    Numerous reports show that lesions to hippocampus afferents, such as the entorhinal cortex (EC) and the fimbria fornix (FF), exert an effect on memory in rodents. There are, however, no long term comparative studies that show which of these lesions could be most useful as a model for studies into neuroplasticity. Young male Sprague Dawley rats were used. Bilateral electrolytic lesion was caused to the EC or the FF was damaged by transection. One, four or 12 weeks later the animals were evaluated in a Morris water maze, first with an invisible platform and then with the platform within view. The results from the two groups were compared to each other and to those obtained from healthy controls and subjects with false lesions by means of a variance analysis. In the test with an invisible platform, both types of lesion gave rise to serious, irreparable involvement of the spatial memory of the animals, at least up to 12 weeks after the lesion. The test with the visible platform revealed significant differences between animals with lesion to the EC evaluated at 12 weeks, which suggests the development of some visual or motor deterioration in these animals. Although both lesions gave rise to behavioural deterioration that was irreversible in the long term in rodents, the lesion to the FF seems to be a better model for evaluating specific effects on learning and memory, since the lesion to the EC apparently triggers additional sensory and motor involvement.

  19. Dopaminergic regulation of neuronal excitability through modulation of Ih in layer V entorhinal cortex.

    PubMed

    Rosenkranz, J Amiel; Johnston, Daniel

    2006-03-22

    The entorhinal cortex (EC) is a significant component of the systems that underlie certain forms of memory formation and recall. Evidence has been emerging that the dopaminergic system in the EC facilitates these and other functions of the EC. The effects of dopamine (DA) on membrane properties and excitability of EC neurons, however, are not known. We used in vitro whole-cell patch-clamp recordings from layer V pyramidal neuronal somata and dendrites of the adult rat lateral EC to investigate the effects of DA on the excitability of these neurons. We found that brief application of DA caused a reduction in the excitability of layer V EC pyramidal neurons. This effect was attributable to voltage-dependent modification of membrane properties that can best be explained by an increase in a hyperpolarization-activated conductance. Furthermore, the effects of DA were blocked by pharmacological blockade of h-channels, but not by any of a number of other ion channels. These actions were produced by a D1 receptor-mediated increase of cAMP but were independent of protein kinase A. A portion of the actions of DA can be attributed to effects in the apical dendrites. The data suggest that DA can directly influence the membrane properties of layer V EC pyramidal neurons by modulation of h-channels. These actions may underlie some of the effects of DA on memory formation.

  20. Innervation from the entorhinal cortex to the dentate gyrus and the vulnerability to Zn(2).

    PubMed

    Takeda, Atsushi; Tamano, Hanuna

    2016-12-01

    Hippocampal Zn(2+) homeostasis is critical for cognitive activity and hippocampus-dependent memory. Extracellular Zn(2+) signaling is linked to extracellular glutamate signaling and leads to intracellular Zn(2+) signaling, which is involved in cognitive activity. On the other hand, excess intracellular Zn(2+) signaling that is induced by excess glutamate signaling is involved in cognitive decline. In the hippocampal formation, the dentate gyrus is the most vulnerable to aging and is thought to contribute to age-related cognitive decline. The layer II of the entorhinal cortex is the most vulnerable to neuronal death in Alzheimer's disease. The perforant pathway provides input from the layer II to the dentate gyrus and is one of the earliest affected pathways in Alzheimer's disease. Medial perforant pathway-dentate granule cell synapses are vulnerable to either excess intracellular Zn(2+) or β-amyloid (Aβ)-bound zinc, which induce transient cognitive decline via attenuation of medial perforant pathway LTP. However, it is unknown whether the vulnerability to excess intracellular Zn(2+) is involved in region-specific vulnerability to aging and Alzheimer's disease. To discover a strategy to prevent short-term cognitive decline in normal aging process and the pre-dementia stage of Alzheimer's disease, the present paper deals with vulnerability of medial perforant pathway-dentate granule cell synapses to intracellular Zn(2+) dyshomeostasis and its possible involvement in differential vulnerability to aging and Alzheimer's disease in the hippocampal formation.

  1. The Role of the Human Entorhinal Cortex in a Representational Account of Memory

    PubMed Central

    Schultz, Heidrun; Sommer, Tobias; Peters, Jan

    2015-01-01

    Connectivity studies in animals form the basis for a representational view of medial temporal lobe (MTL) subregions. In this view, distinct subfields of the entorhinal cortex (EC) relay object-related and spatial information from the perirhinal and parahippocampal cortices (PRC, PHC) to the hippocampus (HC). Relatively recent advances in functional magnetic resonance imaging (fMRI) methodology allow examining properties of human EC subregions directly. Antero-lateral and posterior-medial EC subfields show remarkable consistency to their putative rodent and nonhuman primate homologs with regard to intra- and extra-MTL functional connectivity. Accordingly, there is now evidence for a dissociation of object-related vs. spatial processing in human EC subfields. Here, variance in localization may be integrated in the antero-lateral vs. posterior-medial distinction, but may additionally reflect process differences. Functional results in rodents further suggest material-specific representations may be more integrated in EC compared to PRC/PHC. In humans, however, evidence for such a dissociation between EC and PRC/PHC is lacking. Future research may elucidate on the unique contributions of human EC to memory, especially in light of its high degree of intrinsic and extrinsic connectivity. A thorough characterization of EC subfield function may not only advance our understanding of human memory, but also have important clinical implications. PMID:26635581

  2. Increasing Acetylcholine Levels in the Hippocampus or Entorhinal Cortex Reverses the Impairing Effects of Septal GABA Receptor Activation on Spontaneous Alternation

    PubMed Central

    Degroot, Aldemar; Parent, Marise B.

    2000-01-01

    Intra-septal infusions of the γ-aminobutyric acid (GABA) agonist muscimol impair learning and memory in a variety of tasks. This experiment determined whether hippocampal or entorhinal infusions of the acetylcholinesterase inhibitor physostigmine would reverse such impairing effects on spontaneous alternation performance, a measure of spatial working memory. Male Sprague-Dawley rats were given intra-septal infusions of vehicle or muscimol (1 nmole/0.5 μL) combined with unilateral intra-hippocampal or intra-entorhinal infusions of vehicle or physostigmine (10 μg/μL for the hippocampus; 7.5 μg/μL or 1.875 μg/0.25 μL for the entorhinal cortex). Fifteen minutes later, spontaneous alternation performance was assessed. The results indicated that intra-septal infusions of muscimol significantly decreased percentage-of-alternation scores, whereas intra-hippocampal or intra-entorhinal infusions of physostigmine had no effect. More importantly, intra-hippocampal or intra-entorhinal infusions of physostigmine, at doses that did not influence performance when administered alone, completely reversed the impairing effects of the muscimol infusions. These findings indicate that increasing cholinergic levels in the hippocampus or entorhinal cortex is sufficient to reverse the impairing effects of septal GABA receptor activation and support the hypothesis that the impairing effects of septal GABAergic activity involve cholinergic processes in the hippocampus and the entorhinal cortex. PMID:11040261

  3. Precocious development of parvalbumin-like immunoreactive interneurons in the hippocampal formation and entorhinal cortex of the fetal cynomolgus monkey.

    PubMed

    Berger, B; De Grissac, N; Alvarez, C

    1999-01-18

    The calcium-binding protein parvalbumin (PV), a reliable marker of the hippocampal basket and chandelier cells, is first expressed on embryonic day 83 (E83), corresponding to midgestation of the macaque monkey, in restricted hippocampal groups of immature neurons (Berger and Alvarez [1996] J. Comp. Neurol. 366:674-699). In the present study, PV-like immunoreactivity (LIR) was used to follow the further development of this subclass of interneurons. Asynchronous area-specific developmental sequences were observed, predominating initially in the caudal half of the hippocampal formation and the laterocaudal division of the entorhinal cortex and occurring relatively simultaneously in the interconnected hippocampal and entorhinal subfields. Dendritic elongation of PV-like immunoreactive interneurons and perisomatic distribution of PV-like immunoreactive terminal boutons on their cellular targets were first observed in the subiculum around E127; then from E127 to E142 in CA3/CA2 and layers III-V of the entorhinal cortex and, to a lesser extent in CA1, the dentate hilus and deep granule cell layer; and finally from E156 to postnatal day 12 in the rest of the dentate gyrus, the presubiculum and parasubiculum, and layers III-II-I of the entorhinal cortex. These data provide the first indication that a population of basket cells, a major gamma-aminobutyric acid (GABA)ergic component of the hippocampal intrinsic inhibitory circuitry, reaches its cellular targets several weeks before birth in primates in contrast to rodents. The role of the prenatal PV expression in the hippocampal formation of nonhuman primates and whether it coincides with the onset of postsynaptic inhibitory potentials or is accompanied or preceded by a period of gamma-aminobutyric acid-mediated excitatory effects as in rat pups, are crucial questions. They underline the need to pursue direct investigations on primates to be able to legitimately extrapolate the data obtained in rodents.

  4. Cellular resolution optical access to brain regions in fissures: imaging medial prefrontal cortex and grid cells in entorhinal cortex.

    PubMed

    Low, Ryan J; Gu, Yi; Tank, David W

    2014-12-30

    In vivo two-photon microscopy provides the foundation for an array of powerful techniques for optically measuring and perturbing neural circuits. However, challenging tissue properties and geometry have prevented high-resolution optical access to regions situated within deep fissures. These regions include the medial prefrontal and medial entorhinal cortex (mPFC and MEC), which are of broad scientific and clinical interest. Here, we present a method for in vivo, subcellular resolution optical access to the mPFC and MEC using microprisms inserted into the fissures. We chronically imaged the mPFC and MEC in mice running on a spherical treadmill, using two-photon laser-scanning microscopy and genetically encoded calcium indicators to measure network activity. In the MEC, we imaged grid cells, a widely studied cell type essential to memory and spatial information processing. These cells exhibited spatially modulated activity during navigation in a virtual reality environment. This method should be extendable to other brain regions situated within deep fissures, and opens up these regions for study at cellular resolution in behaving animals using a rapidly expanding palette of optical tools for perturbing and measuring network structure and function.

  5. A phase code for memory could arise from circuit mechanisms in entorhinal cortex

    PubMed Central

    Hasselmo, Michael E.; Brandon, Mark P.; Yoshida, Motoharu; Giocomo, Lisa M.; Heys, James G.; Fransen, Erik; Newman, Ehren L.; Zilli, Eric A.

    2009-01-01

    Neurophysiological data reveals intrinsic cellular properties that suggest how entorhinal cortical neurons could code memory by the phase of their firing. Potential cellular mechanisms for this phase coding in models of entorhinal function are reviewed. This mechanism for phase coding provides a substrate for modeling the responses of entorhinal grid cells, as well as the replay of neural spiking activity during waking and sleep. Efforts to implement these abstract models in more detailed biophysical compartmental simulations raise specific issues that could be addressed in larger scale population models incorporating mechanisms of inhibition. PMID:19656654

  6. Serotonin increases GABA release in rat entorhinal cortex by inhibiting interneuron TASK-3 K+ channels.

    PubMed

    Deng, Pan-Yue; Lei, Saobo

    2008-10-01

    Whereas the entorhinal cortex (EC) receives profuse serotonergic innervations from the raphe nuclei in the brain stem and is critically involved in the generation of temporal lobe epilepsy, the function of serotonin (5-hydroxytryptamine, 5-HT) in the EC and particularly its roles in temporal lobe epilepsy are still elusive. Here we explored the cellular and molecular mechanisms underlying 5-HT-mediated facilitation of GABAergic transmission and depression of epileptic activity in the superficial layers of the EC. Application of 5-HT increased sIPSC frequency and amplitude recorded from the principal neurons in the EC with no effects on mIPSCs recorded in the presence of TTX. However, 5-HT reduced the amplitude of IPSCs evoked by extracellular field stimulation and in synaptically connected interneuron and pyramidal neuron pairs. Application of 5-HT generated membrane depolarization and increased action potential firing frequency but reduced the amplitude of action potentials in presynaptic interneurons suggesting that 5-HT still increases GABA release whereas the depressant effects of 5-HT on evoked IPSCs could be explained by 5-HT-induced reduction in action potential amplitude. The depolarizing effect of 5-HT was mediated by inhibition of TASK-3 K(+) channels in interneurons and required the functions of 5-HT(2A) receptors and Galpha(q/11) but was independent of phospholipase C activity. Application of 5-HT inhibited low-Mg(2+)-induced seizure activity in slices via 5-HT(1A) and 5-HT(2A) receptors suggesting that 5-HT-mediated depression of neuronal excitability and increase in GABA release contribute to its anti-epileptic effects in the EC.

  7. On the role of the entorhinal cortex in the effective connectivity of the hippocampal formation.

    PubMed

    López-Madrona, Víctor J; Matias, Fernanda S; Pereda, Ernesto; Canals, Santiago; Mirasso, Claudio R

    2017-04-01

    Inferring effective connectivity from neurophysiological data is a challenging task. In particular, only a finite (and usually small) number of sites are simultaneously recorded, while the response of one of these sites can be influenced by other sites that are not being recorded. In the hippocampal formation, for instance, the connections between areas CA1-CA3, the dentate gyrus (DG), and the entorhinal cortex (EC) are well established. However, little is known about the relations within the EC layers, which might strongly affect the resulting effective connectivity estimations. In this work, we build excitatory/inhibitory neuronal populations representing the four areas CA1, CA3, the DG, and the EC and fix their connectivities. We model the EC by three layers (LII, LIII, and LV) and assume any possible connection between them. Our results, based on Granger Causality (GC) and Partial Transfer Entropy (PTE) measurements, reveal that the estimation of effective connectivity in the hippocampus strongly depends on the connectivities between EC layers. Moreover, we find, for certain EC configurations, very different results when comparing GC and PTE measurements. We further demonstrate that causal links can be robustly inferred regardless of the excitatory or inhibitory nature of the connection, adding complexity to their interpretation. Overall, our work highlights the importance of a careful analysis of the connectivity methods to prevent unrealistic conclusions when only partial information about the experimental system is available, as usually happens in brain networks. Our results suggest that the combination of causality measures with neuronal modeling based on precise neuroanatomical tracing may provide a powerful framework to disambiguate causal interactions in the brain.

  8. Relative contributions of CA3 and medial entorhinal cortex to memory in rats

    PubMed Central

    O'Reilly, Kally C.; Alarcon, Juan M.; Ferbinteanu, Janina

    2014-01-01

    The hippocampal CA1 field processes spatial information, but the relative importance of intra- vs. extra-hippocampal sources of input into CA1 for spatial behavior is unclear. To characterize the relative roles of these two sources of input, originating in the hippocampal field CA3 and in the medial entorhinal cortex (MEC), we studied effects of discrete neurotoxic lesions of CA3 or MEC on concurrent spatial and nonspatial navigation tasks, and on synaptic transmission in afferents to CA1. Lesions in CA3 or MEC regions that abolished CA3-CA1, or reduced MEC-CA1 synaptic transmission, respectively, impaired spatial navigation and unexpectedly interfered with cue response, suggesting that in certain conditions of training regimen, hippocampal activity may influence behavior otherwise supported by nonhippocampal neural networks. MEC lesions had milder and temporary behavioral effects, but also markedly amplified transmission in the CA3-CA1 pathway. Extensive behavioral training had a similar, but more modest effect on CA3-CA1 transmission. Thus, cortical input to the hippocampus modulates CA1 activity both directly and indirectly, through heterosynaptic interaction, to control information flow in the hippocampal loop. Following damage to hippocampal cortical input, the functional coupling of separate intra- and extra-hippocampal inputs to CA1 involved in normal learning may initiate processes that support recovery of behavioral function. Such a process may explain how CA3 lesions, which do not significantly modify the basic features of CA1 neural activity, nonetheless impair spatial recall, whereas lesions of EC input to CA1, which reduce the spatial selectivity of CA1 firing in foraging rats, have only mild effects on spatial navigation. PMID:25221487

  9. All layers of medial entorhinal cortex receive presubicular and parasubicular inputs.

    PubMed

    Canto, Cathrin B; Koganezawa, Noriko; Beed, Prateep; Moser, Edvard I; Witter, Menno P

    2012-12-05

    The medial entorhinal cortex (MEC), presubiculum (PrS), and parasubiculum (PaS) are interconnected components of the hippocampal-parahippocampal spatial-representation system. Principal cells in all layers of MEC show signs of directional tuning, overt in head direction cells present in all layers except for layer II, and covert in grid cells, which are the major spatially modulated cell type in layer II. Directional information likely originates in the head direction-vestibular system and PrS and PaS are thought to provide this information to MEC. Efferents from PaS and PrS show a selective laminar terminal distribution in MEC superficial layers II and III, respectively. We hypothesized that this anatomically determined laminar distribution does not preclude monosynaptic interaction with neurons located in deeper layers of MEC in view of the extensive apical dendrites from deeper cells reaching layers II and III. This hypothesis was tested in the rat using tilted in vitro slices in which origins and terminations of PrS and PaS fibers were maintained, as assessed using anterograde anatomical tracing. Based on voltage-sensitive dye imaging, multipatch single-cell recordings, and scanning photostimulation of caged glutamate, we report first that principal neurons in all layers of MEC receive convergent monosynaptic inputs from PrS and PaS and second, that elicited responses show layer-specific decay times and frequency-dependent facilitation. These results indicate that regardless of their selective laminar terminal distribution, PrS and PaS inputs may monosynaptically convey directional information to principal neurons in all layers of MEC through synapses on their extensive dendritic arbors.

  10. Behavioural and electrophysiological studies of entorhinal cortex lesions in the rat.

    PubMed

    Hagan, J J; Verheijck, E E; Spigt, M H; Ruigt, G S

    1992-02-01

    Bilateral ibotenic acid injections aimed at the entorhinal cortex (EC) lesioned the EC and subiculum in 30% of animals (group EC/S) and caused additional hippocampal damage in 50% (group RH). Both lesions increased acetylcholinesterase (AChE) staining in the intermediate molecular layer of the dentate gyrus. EC/S lesions increased diurnal deep sleep and the incidence of spindles but decreased REM sleep. RH lesions increased nocturnal deep sleep and decreased nocturnal quiet sleep. Both lesions reduced power over the theta frequency range from 6-10 Hz for epochs of REM sleep and quiet waking but not deep sleep. Peak frequency was unaffected. The RH group and a subset of the EC/S group were nocturnally, but not diurnally, hyperactive. Six weeks after the lesion there was no evidence for hyperactivity in a novel open field. The EC/S lesion impaired exploration as indicated by reduced motility and rearing in an open field and by the failure of EC/S-lesioned rats to increase contact time in response to a novel olfactory cue. Place navigation learning in a Morris maze was not affected by EC/S or RH lesions. However, when the spatial location of the hidden platform was shifted EC/S-lesioned rats were impaired. The sprouting response, reduced theta power and exploration deficits resemble those reported following electrolytic lesions, but the lack of effect on place navigation learning contrasts with reports of impaired spatial learning following electrolytic lesions. The data prompt a reexamination of the role which the EC projection to the hippocampus plays in spatial learning.

  11. ERK activation and expression of neuronal cell cycle markers in the hippocampus after entorhinal cortex lesion.

    PubMed

    Hernández-Ortega, Karina; Arias, Clorinda

    2012-11-01

    Current findings suggest that neuronal cell death is frequently associated with the aberrant expression of cell cycle-regulatory proteins in postmitotic neurons. Aberrant cell cycle reentry has been implicated in diverse neurodegenerative conditions, including Alzheimer's disease (AD). Previously we reported that the appearance of cell cycle markers in postmitotic neurons of the entorhinal cortex (EC) after excitotoxic hippocampal damage is associated with the expression of phospho-tau and amyloid precursor protein (APP). However, the question of the signaling pathway involved in this cell cycle reentry remains unresolved. Differentiated neurons use the molecular mechanisms initially acquired to direct cell proliferation, such as the Ras-extracellular signal-regulated kinase (ERK1/2) pathway, to regulate synaptic plasticity. In this work we explored whether ERK1/2-related signaling might contribute to the cell cycle reentry in hippocampal neurons after a unilateral EC lesion. We showed that, within the first 24 hr after hippocampal deafferentation, numerous neurons expressed phospho-ERK1/2, concomitantly with the gradual increases in cyclin D1 and cyclin B immunoreactivity in the dentate gyrus and hilus. Several of these immunopositive cells to phospho-ERK1/2 and cyclin B in hippocampus are postmitotic neurons, insofar as they are positive to NeuN. The intracisternal administration of U0126 (an MEK inhibitor), previous to the excitotoxic lesion, decreased the activation of ERK1/2 and the expression of cyclin D1 and cyclin B in the hippocampus. The present findings support the notion that ERK1/2 plays a role in cell cycle reactivation in mature neurons efferently connected to the lesion site. Copyright © 2012 Wiley Periodicals, Inc.

  12. The entorhinal cortex, but not the dorsal hippocampus, is necessary for single-cue latent learning.

    PubMed

    Stouffer, Eric M

    2010-09-01

    Two experiments were conducted to examine the roles of the entorhinal cortex (EC), dorsal hippocampus (DH), and ventral hippocampus (VH) in a modified Latent Cue Preference (LCP) task. The modified LCP task utilized one visual cue in each compartment, compared to several multimodal cues used in a previous version. In the single-cue LCP task, water-replete rats drink water in one compartment of the LCP box on 1 day, and then have no water in a second compartment of the LCP box the following day (one training trial), for a total of three training trials. Rats are then water-deprived prior to a preference test, in which they are allowed to move freely between the two compartments with the water removed. Latent learning is demonstrated when water-deprived rats spend more time in the compartment that previously contained the water. Experiment 1 demonstrated that the single-cue LCP task results in the same irrelevant-incentive latent learning as the multicue LCP task. In addition, Experiment 1 replicated the finding that a compartment preference based on this latent learning requires a deprivation state during the preference test, while a compartment preference based on conditioning does not. Experiment 2 examined the effects of pretraining neurotoxin lesions of the EC, DH, and VH on this single-cue LCP task. Results showed that lesions of the EC and VH disrupted the irrelevant-incentive latent learning, while lesions of the DH did not. These results indicate that a latent learning task that involves one discrete compartment cue, rather than several compartmental cues, does not require the DH. Therefore, the EC appears to play a central role in single-cue latent learning in the LCP task.

  13. Influence of the entorhinal cortex on accumbal and striatal dopaminergic responses in a latent inhibition paradigm.

    PubMed

    Jeanblanc, J; Peterschmitt, Y; Hoeltzel, A; Louilot, A

    2004-01-01

    The use of latent inhibition paradigms is one means of investigating the involvement of mesencephalic dopaminergic (DA) neurons in cognitive processes. We have shown recently that DA neurons reaching the core and the dorsomedial shell parts of the nucleus accumbens and the anterior part of the striatum are differentially involved in latent inhibition. In other respects, theoretical, behavioral and anatomo-functional data suggest that the entorhinal cortex (ENT) may control latent inhibition expression. In this study, using in vivo voltammetry in freely moving rats, we investigated the influence of the ENT on the DA responses obtained in the core and dorsomedial shell parts of the nucleus accumbens and the anterior part of the striatum. For this purpose a reversible inactivation of the left ENT was achieved by the local microinjection of tetrodotoxin, 3 h before pre-exposure to the conditional stimulus (banana odour). During the second session, animals were aversively conditioned to banana odour. Results obtained during the third session (test session), in animals submitted to the reversible blockade of the ENT before the first session were as follows: (1) pre-exposed conditioned animals displayed behavioral aversive responses; (2) where core DA responses were concerned, responses were situated between those observed in pre-exposed and non-pre-exposed conditioned animals; (3) by contrast, where the dorsomedial shell part of the nucleus accumbens and the anterior striatum were concerned, DA variations were not statistically different in pre-exposed and non-pre-exposed conditioned rats. These data suggest that the left ENT exerts a crucial influence over the latent-inhibition-related DA responses in the left dorsomedial shell part of the nucleus accumbens and the left anterior part of the striatum, whereas one or more other brain regions control DA variations in the left core part of the nucleus accumbens. These data may help us to understand the pathophysiology of

  14. Cholecystokinin facilitates neuronal excitability in the entorhinal cortex via activation of TRPC-like channels.

    PubMed

    Wang, Shouping; Zhang, An-Ping; Kurada, Lalitha; Matsui, Toshimitsu; Lei, Saobo

    2011-09-01

    Cholecystokinin (CCK) is one of the most abundant neuropeptides in the brain, where it interacts with two G protein-coupled receptors (CCK-1 and CCK-2). Activation of both CCK receptors increases the activity of PLC, resulting in increases in intracellular calcium ion (Ca(2+)) release and activation of PKC. Whereas high density of CCK receptors has been detected in the superficial layers of the entorhinal cortex (EC), the functions of CCK in this brain region have not been determined. Here, we studied the effects of CCK on neuronal excitability of layer III pyramidal neurons in the EC. Our results showed that CCK remarkably increased the firing frequency of action potentials (APs). The effects of CCK on neuronal excitability were mediated via activation of CCK-2 receptors and required the functions of G proteins and PLC. However, CCK-mediated facilitation of neuronal excitability was independent of inositol trisphosphate receptors and PKC. CCK facilitated neuronal excitability by activating a cationic channel to generate membrane depolarization. The effects of CCK were suppressed by the generic, nonselective cationic channel blockers, 2-aminoethyldiphenyl borate and flufenamic acid, but potentiated by gadolinium ion and lanthanum ion at 100 μM. Depletion of extracellular Ca(2+) also counteracted CCK-induced increases in AC firing frequency. Moreover, CCK-induced enhancement of neuronal excitability was inhibited significantly by intracellular application of the antibody to transient receptor potential channel 5 (TRPC5), suggesting the involvement of TRPC5 channels. Our results provide a cellular and molecular mechanism to help explain the functions of CCK in vivo.

  15. Morphology and kainate-receptor immunoreactivity of identified neurons within the entorhinal cortex projecting to superior temporal sulcus in the cynomolgus monkey

    NASA Technical Reports Server (NTRS)

    Good, P. F.; Morrison, J. H.; Bloom, F. E. (Principal Investigator)

    1995-01-01

    Projections of the entorhinal cortex to the hippocampus are well known from the classical studies of Cajal (Ramon y Cajal, 1904) and Lorente de No (1933). Projections from the entorhinal cortex to neocortical areas are less well understood. Such connectivity is likely to underlie the consolidation of long-term declarative memory in neocortical sites. In the present study, a projection arising in layer V of the entorhinal cortex and terminating in a polymodal association area of the superior temporal gyrus has been identified with the use of retrograde tracing. The dendritic arbors of neurons giving rise to this projection were further investigated by cell filling and confocal microscopy with computer reconstruction. This analysis demonstrated that the dendritic arbor of identified projection neurons was largely confined to layer V, with the exception of a solitary, simple apical dendrite occasionally ascending to superficial laminae but often confined to the lamina dissecans (layer IV). Finally, immunoreactivity for glutamate-receptor subunit proteins GluR 5/6/7 of the dendritic arbor of identified entorhinal projection neurons was examined. The solitary apical dendrite of identified entorhinal projection neurons was prominently immunolabeled for GluR 5/6/7, as was the dendritic arbor of basilar dendrites of these neurons. The restriction of the large bulk of the dendritic arbor of identified entorhinal projection neurons to layer V implies that these neurons are likely to be heavily influenced by hippocampal output arriving in the deep layers of the entorhinal cortex. Immunoreactivity for GluR 5/6/7 throughout the dendritic arbor of such neurons indicates that this class of glutamate receptor is in a position to play a prominent role in mediating excitatory neurotransmission within hippocampal-entorhinal circuits.

  16. Mapping the early development of projections from the entorhinal cortex in the embryonic mouse using prenatal surgery techniques.

    PubMed

    Snyder, D C; Coltman, B W; Muneoka, K; Ide, C F

    1991-12-01

    The purpose of this work was to study the development of specific projections from the postero-lateral cortex during the third trimester of gestation in the mouse. To do this, we labeled undifferentiated lateral cortex with the fluorescent carbocyanine dye, Dil, in the embryonic day (E) 16 mouse embryo using exo utero surgical techniques (Muneoka, Wanek, and Bryant, 1986). Embryos were allowed to develop to term (postnatal day 0, P0) at which time the fiber patterns emanating from the marked regions were studied. Dye placement in the undifferentiated postero-ventral cortex produced labeled fibers in the hippocampal formation. A robust projection of the angular bundle into the CA1 region of the hippocampus was heavily labeled. In addition, in some animals, cortical tracts, such as the anterior commissure, corpus callosum, and a corticotectal tract, were labeled. These tracts have been described previously as scaffolding pathways in the fetal cat (McConnell, Ghosh, and Shatz, 1989), and other vertebrates (Wilson, Ross, Parrett, and Easter, 1990). Dye placement in adjacent, more anterior or dorsal areas showed strong labeling in cortical structures but no labeling in the hippocampal formation. These data indicate that, by birth, the temporal cortex is subdivided along the rostro-caudal axis as entorhinal cortex and perirhinal cortex, and along the dorso-ventral axis, as entorhinal cortex and neocortex. Also, these earliest connections are similar to adult connections in their specificity of target area selection. Therefore, these early, yet specific, connections may play a role int he formation of future connections during postnatal development.

  17. Loss of entorhinal cortex and hippocampal volumes compared to whole brain volume in normal aging: the SMART-Medea study.

    PubMed

    Knoops, Arnoud J G; Gerritsen, Lotte; van der Graaf, Yolanda; Mali, Willem P T M; Geerlings, Mirjam I

    2012-07-30

    In non-demented elderly age-related decline in hippocampal volume has often been observed, but it is not clear if this loss is disproportionate relative to other brain tissue. Few studies examined age-related volume loss of the entorhinal cortex. We investigated the association of age with hippocampal and entorhinal cortex (ERC) volumes in a large sample of middle-aged and older persons without dementia. Within the SMART-Medea study, cross-sectional analyses were performed in 453 non-demented subjects (mean age 62±9 years, 81% male) with a history of arterial disease. Hippocampal and ERC volumes were assessed by manual segmentation on three-dimensional fast field-echo sequence T1-weighted magnetic resonance images. Automated segmentation was used to quantify volumes of BV and ICV. Hippocampal and ERC volumes were divided by intracranial volume (ICV) as well as total brain volume (BV) to determine whether age-related differences were disproportionate relative to other brain tissue. Total crude hippocampal volume was 5.96±0.7 ml and total crude ERC volume was 0.34±0.06 ml. Linear regression analyses adjusted for sex showed that with increasing age, hippocampal volume divided by ICV decreased (B per year older=-0.01 ml; 95% CI -0.02 to -0.004). However, no age-related decline in hippocampal volume relative to BV was observed (B per year older=0.005 ml; 95% CI -0.002 to 0.01). No age-related decline in ERC volume relative to ICV or BV was observed. In this population of nondemented patients with a history of vascular disease no age-related decline in entorhinal cortex volume was observed and although hippocampal volume decreased with age, it was not disproportionate relative to total brain volume. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  18. Entorhinal cortex lesions result in adenosine-sensitive high frequency oscillations in the hippocampus.

    PubMed

    Ortiz, Franco; Gutiérrez, Rafael

    2015-09-01

    Entorhinal cortex (EC) projections to the hippocampus run along the perforant path and activate the hippocampal area CA3 and the dentate gyrus (DG), which, in turn, drives CA3. Because cortical trauma damages the source of inputs to the hippocampus, we hypothesize that such an event can be reflected in immediate alterations of the hippocampal oscillatory activity. We here explore whether acute, localized disruption of EC-EC connectivity is involved in the generation or modulation of high frequency oscillations (HFOs) in the hippocampus. We conducted in vitro electrophysiological recordings in CA3 and DG of combined EC-hippocampal transversal slices prepared from intact brains and from brains with a spatially defined, transversal cut of the EC made in situ, 2h before in vitro recordings commenced. We also determined if pharmacological manipulations of the adenosine system modulated the fast oscillatory activity. EC-hippocampal slices prepared from brains, in which a transversal lesion of the EC was uni- or bilaterally conducted in situ, displayed spontaneous epileptiform events with superimposed ripples (150-250 Hz) and fast ripples (>250 Hz), whereas those obtained from non-lesioned brains did not have spontaneous HFOs. However, in the latter, high frequency stimulation applied to the perforant path produced ripple activity in area CA3. Spontaneous fast ripples were prevented by conducting the slicing procedure and incubating the slices both in a Na(+)-free medium and in a low Ca(++)-high Mg(++) medium for an hour before recording commenced, under normal Na(+) concentration. Activation of A1, but not A2, receptors produced a strong inhibition of the incidence and spectral power of fast ripples but did not change their intrinsic frequency. Our data show that the disruption of EC-to-EC connections can immediately disinhibit hippocampal CA3 area to generate HFOs on top of epileptiform events, probably constituting an irritating focus long before overt epileptic

  19. BDNF and trkB mRNA expression in the rat hippocampus following entorhinal cortex lesions.

    PubMed

    Lapchak, P A; Araujo, D M; Hefti, F

    1993-02-01

    Quantitative in situ hybridization was used to determine whether the prevalence or topographical distribution of brain-derived neurotrophic factor (BDNF) or tyrosine receptor kinase (trk) B mRNA is altered in the hippocampal formation following lesions of excitatory afferents from the entorhinal cortex which provides an external source of innervation for the hippocampal formation. BDNF mRNA levels were not altered in the hippocampal formation up to 10 days following entorhinal cortex lesions (ECLs). The levels of mRNA coding for all known forms of trkB receptors also remained unchanged. The prevalence of the synaptic plasticity marker SNAP-25 mRNA was increased in the CA2 and CA3 pyramidal cell layers and the dentate gyrus by 6 days following ECLs and remained elevated at 10 days following ECLs. Our findings indicate that hippocampal neuron sprouting which occurs in response to ECLs is not the result of changes in the expression of the BDNF or trkB mRNA.

  20. Imidacloprid toxicity impairs spatial memory of echolocation bats through neural apoptosis in hippocampal CA1 and medial entorhinal cortex areas.

    PubMed

    Hsiao, Chun-Jen; Lin, Ching-Lung; Lin, Tian-Yu; Wang, Sheue-Er; Wu, Chung-Hsin

    2016-04-13

    It has been reported that the decimation of honey bees was because of pesticides of imidacloprid. The imidacloprid is a wildly used neonicotinoid insecticide. However, whether imidacloprid toxicity interferes with the spatial memory of echolocation bats is still unclear. Thus, we compared the spatial memory of Formosan leaf-nosed bats, Hipposideros terasensis, before and after chronic treatment with a low dose of imidacloprid. We observed that stereotyped flight patterns of echolocation bats that received chronic imidacloprid treatment were quite different from their originally learned paths. We further found that neural apoptosis in hippocampal CA1 and medial entorhinal cortex areas of echolocation bats that received imidacloprid treatment was significantly enhanced in comparison with echolocation bats that received sham treatment. Thus, we suggest that imidacloprid toxicity may interfere with the spatial memory of echolocation bats through neural apoptosis in hippocampal CA1 and medial entorhinal cortex areas. The results provide direct evidence that pesticide toxicity causes a spatial memory disorder in echolocation bats. This implies that agricultural pesticides may pose severe threats to the survival of echolocation bats.

  1. Subthreshold resonance explains the frequency-dependent integration of periodic as well as random stimuli in the entorhinal cortex.

    PubMed

    Schreiber, Susanne; Erchova, Irina; Heinemann, Uwe; Herz, Andreas V M

    2004-07-01

    Neurons integrate subthreshold inputs in a frequency-dependent manner. For sinusoidal stimuli, response amplitudes thus vary with stimulus frequency. Neurons in entorhinal cortex show two types of such resonance behavior: stellate cells in layer II exhibit a prominent peak in the resonance profile at stimulus frequencies of 5-16 Hz. Pyramidal cells in layer III show only a small impedance peak at low frequencies (1-5 Hz) or a maximum at 0 Hz followed by a monotonic decrease of the impedance. Whether the specific frequency selectivity for periodic stimuli also governs the integration of non-periodic stimuli has been questioned recently. Using frozen-noise stimuli with different distributions of power over frequencies, we provide experimental evidence that the integration of non-periodic subthreshold stimuli is determined by the same subthreshold frequency selectivity as that of periodic stimuli. Differences between the integration of noise stimuli in stellate and pyramidal cells can be fully explained by the resonance properties of each cell type. Response power thus reflects stimulus power in a frequency-selective way. Theoretical predictions based on linear system's theory as well as on conductance-based model neurons support this finding. We also show that the frequency selectivity in the subthreshold range extends to suprathreshold responses in terms of firing rate. Cells in entorhinal cortex are representative examples of cells with resonant or low-pass filter impedance profiles. It is therefore likely that neurons with similar frequency selectivity will process input signals according to the same simple principles.

  2. A map of abstract relational knowledge in the human hippocampal-entorhinal cortex.

    PubMed

    Garvert, Mona M; Dolan, Raymond J; Behrens, Timothy Ej

    2017-04-27

    The hippocampal-entorhinal system encodes a map of space that guides spatial navigation. Goal-directed behaviour outside of spatial navigation similarly requires a representation of abstract forms of relational knowledge. This information relies on the same neural system, but it is not known whether the organisational principles governing continuous maps may extend to the implicit encoding of discrete, non-spatial graphs. Here, we show that the human hippocampal-entorhinal system can represent relationships between objects using a metric that depends on associative strength. We reconstruct a map-like knowledge structure directly from a hippocampal-entorhinal functional magnetic resonance imaging adaptation signal in a situation where relationships are non-spatial rather than spatial, discrete rather than continuous, and unavailable to conscious awareness. Notably, the measure that best predicted a behavioural signature of implicit knowledge and blood oxygen level-dependent adaptation was a weighted sum of future states, akin to the successor representation that has been proposed to account for place and grid-cell firing patterns.

  3. A map of abstract relational knowledge in the human hippocampal–entorhinal cortex

    PubMed Central

    Garvert, Mona M; Dolan, Raymond J; Behrens, Timothy EJ

    2017-01-01

    The hippocampal–entorhinal system encodes a map of space that guides spatial navigation. Goal-directed behaviour outside of spatial navigation similarly requires a representation of abstract forms of relational knowledge. This information relies on the same neural system, but it is not known whether the organisational principles governing continuous maps may extend to the implicit encoding of discrete, non-spatial graphs. Here, we show that the human hippocampal–entorhinal system can represent relationships between objects using a metric that depends on associative strength. We reconstruct a map-like knowledge structure directly from a hippocampal–entorhinal functional magnetic resonance imaging adaptation signal in a situation where relationships are non-spatial rather than spatial, discrete rather than continuous, and unavailable to conscious awareness. Notably, the measure that best predicted a behavioural signature of implicit knowledge and blood oxygen level-dependent adaptation was a weighted sum of future states, akin to the successor representation that has been proposed to account for place and grid-cell firing patterns. DOI: http://dx.doi.org/10.7554/eLife.17086.001 PMID:28448253

  4. Highest trkB mRNA expression in the entorhinal cortex among hippocampal subregions in the adult rat: contrasting pattern with BDNF mRNA expression.

    PubMed

    Tokuyama, W; Hashimoto, T; Li, Y X; Okuno, H; Miyashita, Y

    1998-11-20

    Brain-derived neurotrophic factor (BDNF) and its receptor, TrkB, regulate synaptic functions in the hippocampus of the adult rodent. In previous studies, in situ hybridization methods have been used to evaluate regional differences in BDNF and trkB mRNA expression levels in hippocampal subregions. However, these studies have failed to reach consensus regarding the regional differences in the mRNA expression levels. In the present study, we quantitated mRNA expression levels using two different methods, ribonuclease protection assays and a quantitative reverse-transcription polymerase chain reaction technique, in four hippocampal subregions: the entorhinal cortex, dentate gyrus (DG), CA3 and CA1. These two methods yielded the same results. We found that BDNF and trkB mRNA expression levels did not covary in the four subregions. BDNF and full length trkB (trkB FL) mRNA in the entorhinal cortex and the DG show contrasting expression patterns. The expression level of BDNF mRNA was highest in the DG among the hippocampal subregions and low in the entorhinal cortex and the CA1, whereas the trkB FL mRNA expression level was highest in the entorhinal cortex, low in the DG and lowest in the CA3. These results suggest regional differences in BDNF/TrkB signaling for maintenance and modifiability of neuronal connections in the hippocampal formation.

  5. Anticonvulsant effects of N6-cyclohexyladenosine microinjected into the CA1 region of the hippocampus on entorhinal cortex-kindled seizures in rats.

    PubMed

    Heidarianpour, Ali; Sadeghian, Efat; Mirnajafi-Zadeh, Javad; Fathollahi, Yaghoub; Mohammad-Zadeh, Mohammad

    2006-12-01

    In this study, the role of adenosine A1 receptors of the hippocampal CA1 region in entorhinal cortex-kindled seizures was investigated in rats. Animals were kindled by daily electrical stimulation of the entorhinal cortex. In fully kindled rats, N(6)-cyclohexyladenosine (CHA; a selective A1 receptor agonist) and 1, 3-dimethyl-8-cyclopenthylxanthine (CPT; a selective A1 receptor antagonist) were microinfused bilaterally into the hippocampal CA1 region. Rats were stimulated and seizure parameters were measured. Results obtained showed that CHA (10 and 50 micro moles) decreased the afterdischarge duration (ADD) in the hippocampal CA1 region and entorhinal cortex, stage 5 seizure duration (S5D) and seizure duration (SD) only at the dose of 50 micro moles, and significantly increased the latency to stage 4 (S4L). Intrahippocampal CPT increased ADD and S5D, and significantly reduced the latency to stage 4 (S4L) at the dose of 10 micromoles. Pretreatment of rats with CPT (5 micro moles) before CHA (50 micro moles), significantly reduced the effect of CHA on seizure parameters. The results suggest that the CA1 region of the hippocampus plays an important role in spreading seizure spikes from the entorhinal cortex to other brain regions and activation of adenosine A1 receptors in this region participates in the anticonvulsant effects of adenosine agonists.

  6. Differential Contribution of Kainate Receptors to EPSCs in Superficial Layer Neurons of the Rat Medial Entorhinal Cortex

    PubMed Central

    West, Peter J.; Dalpé-Charron, Alexandre; Wilcox, Karen S.

    2009-01-01

    Although in situ hybridization studies have revealed the presence of kainate receptor (KAR) mRNA in neurons of the rat medial entorhinal cortex (mEC), the functional presence and roles of these receptors are only beginning to be examined. To address this deficiency, whole cell voltage clamp recordings of locally evoked EPSCs were made from mEC layer II and III neurons in combined entorhinal cortex -hippocampal brain slices. Three types of neurons were identified by their electroresponsive membrane properties, locations, and morphologies: stellate-like “Sag” neurons in layer II (S), pyramidal-like “No Sag” neurons in layer III (NS), and “Intermediate Sag” neurons with varied morphologies and locations (IS). Non-NMDA EPSCs in these neurons were composed of two components, and the slow decay component in NS neurons had larger amplitudes and contributed more to the combined EPSC than did those observed in S and IS neurons. This slow component was mediated by KARs and was characterized by its resistance to either GYKI 52466 (100 μM) or NBQX (1 μM), relatively slow decay kinetics, and sensitivity to CNQX (10–50 μM). KAR mediated EPSCs in pyramidal-like NS neurons contributed significantly more to the combined non-NMDA EPSC than did those from S and IS neurons. Layer III neurons of the mEC are selectively susceptible to degeneration in human temporal lobe epilepsy (TLE) and animal models of TLE such as kainate-induced status epilepticus. Characterizing differences in the complement of postsynaptic receptors expressed in injury prone versus injury resistant mEC neurons represents an important step toward understanding the vulnerability of layer III neurons seen in TLE. PMID:17395391

  7. Processing of spatial and non-spatial information in rats with lesions of the medial and lateral entorhinal cortex: Environmental complexity matters.

    PubMed

    Rodo, Christophe; Sargolini, Francesca; Save, Etienne

    2017-03-01

    The entorhinal-hippocampal circuitry has been suggested to play an important role in episodic memory but the contribution of the entorhinal cortex remains elusive. Predominant theories propose that the medial entorhinal cortex (MEC) processes spatial information whereas the lateral entorhinal cortex (LEC) processes non spatial information. A recent study using an object exploration task has suggested that the involvement of the MEC and LEC spatial and non-spatial information processing could be modulated by the amount of information to be processed, i.e. environmental complexity. To address this hypothesis we used an object exploration task in which rats with excitotoxic lesions of the MEC and LEC had to detect spatial and non-spatial novelty among a set of objects and we varied environmental complexity by decreasing the number of objects or amount of object diversity. Reducing diversity resulted in restored ability to process spatial and non-spatial information in MEC and LEC groups, respectively. Reducing the number of objects yielded restored ability to process non-spatial information in the LEC group but not the ability to process spatial information in the MEC group. The findings indicate that the MEC and LEC are not strictly necessary for spatial and non-spatial processing but that their involvement depends on the complexity of the information to be processed.

  8. Temporally structured replay of neural activity in a model of entorhinal cortex, hippocampus and postsubiculum

    PubMed Central

    Hasselmo, Michael E.

    2008-01-01

    The spiking activity of hippocampal neurons during REM sleep exhibits temporally structured replay of spiking occurring during previously experienced trajectories (Louie and Wilson, 2001). Here, temporally structured replay of place cell activity during REM sleep is modeled in a large-scale network simulation of grid cells, place cells and head direction cells. During simulated waking behavior, the movement of the simulated rat drives activity of a population of head direction cells that updates the activity of a population of entorhinal grid cells. The population of grid cells drives the activity of place cells coding individual locations. Associations between location and movement direction are encoded by modification of excitatory synaptic connections from place cells to speed modulated head direction cells. During simulated REM sleep, the population of place cells coding an experienced location activates the head direction cells coding the associated movement direction. Spiking of head direction cells then causes frequency shifts within the population of entorhinal grid cells to update a phase representation of location. Spiking grid cells then activate new place cells that drive new head direction activity. In contrast to models that perform temporally compressed sequence retrieval similar to sharp wave activity, this model can simulate data on temporally structured replay of hippocampal place cell activity during REM sleep at time scales similar to those observed during waking. These mechanisms could be important for episodic memory of trajectories. PMID:18973557

  9. The medial prefrontal cortex-lateral entorhinal cortex circuit is essential for episodic-like memory and associative object-recognition.

    PubMed

    Chao, Owen Y; Huston, Joseph P; Li, Jay-Shake; Wang, An-Li; de Souza Silva, Maria A

    2016-05-01

    The prefrontal cortex directly projects to the lateral entorhinal cortex (LEC), an important substrate for engaging item-associated information and relaying the information to the hippocampus. Here we ask to what extent the communication between the prefrontal cortex and LEC is critically involved in the processing of episodic-like memory. We applied a disconnection procedure to test whether the interaction between the medial prefrontal cortex (mPFC) and LEC is essential for the expression of recognition memory. It was found that male rats that received unilateral NMDA lesions of the mPFC and LEC in the same hemisphere, exhibited intact episodic-like (what-where-when) and object-recognition memories. When these lesions were placed in the opposite hemispheres (disconnection), episodic-like and associative memories for object identity, location and context were impaired. However, the disconnection did not impair the components of episodic memory, namely memory for novel object (what), object place (where) and temporal order (when), per se. Thus, the present findings suggest that the mPFC and LEC are a critical part of a neural circuit that underlies episodic-like and associative object-recognition memory.

  10. Cell Type-Specific Differences in Spike Timing and Spike Shape in the Rat Parasubiculum and Superficial Medial Entorhinal Cortex.

    PubMed

    Ebbesen, Christian Laut; Reifenstein, Eric Torsten; Tang, Qiusong; Burgalossi, Andrea; Ray, Saikat; Schreiber, Susanne; Kempter, Richard; Brecht, Michael

    2016-07-26

    The medial entorhinal cortex (MEC) and the adjacent parasubiculum are known for their elaborate spatial discharges (grid cells, border cells, etc.) and the precessing of spikes relative to the local field potential. We know little, however, about how spatio-temporal firing patterns map onto cell types. We find that cell type is a major determinant of spatio-temporal discharge properties. Parasubicular neurons and MEC layer 2 (L2) pyramids have shorter spikes, discharge spikes in bursts, and are theta-modulated (rhythmic, locking, skipping), but spikes phase-precess only weakly. MEC L2 stellates and layer 3 (L3) neurons have longer spikes, do not discharge in bursts, and are weakly theta-modulated (non-rhythmic, weakly locking, rarely skipping), but spikes steeply phase-precess. The similarities between MEC L3 neurons and MEC L2 stellates on one hand and parasubicular neurons and MEC L2 pyramids on the other hand suggest two distinct streams of temporal coding in the parahippocampal cortex.

  11. Cholinergic receptor activation induces a relative facilitation of synaptic responses in the entorhinal cortex during theta- and gamma-frequency stimulation of parasubicular inputs.

    PubMed

    Sparks, D W; Chapman, C A

    2013-01-29

    The parasubiculum sends its single major output to layer II of the entorhinal cortex, and it may therefore interact with inputs to the entorhinal cortex from other cortical areas, and help to shape the activity of layer II entorhinal cells that project to the hippocampal formation. Cholinergic inputs are thought to contribute to the generation of theta- and gamma-frequency activities in the parasubiculum and entorhinal cortex, and the present study assessed how cholinergic receptor activation affects synaptic responses of the entorhinal cortex to theta- and gamma-frequency stimulation. Depth profiles of field excitatory postsynaptic potentials (fEPSPs) in acute brain slices showed a short-latency negative fEPSP in layer II, consistent with the activation of excitatory synaptic inputs to layer II. Application of the cholinergic agonist carbachol (CCh) suppressed synaptic responses and enhanced paired-pulse facilitation. CCh also resulted in a marked relative facilitation of synaptic responses evoked during short 5-pulse trains of stimulation at both theta- and gamma-frequencies. Application of the M(1) antagonist pirenzepine, but not the M(2) antagonist methoctramine, blocked the facilitation of responses. Inhibition of the M-current or block of GABA(B) receptors had no effect, but the facilitation effect was partially blocked by the N-methyl-d-aspartate (NMDA) antagonist APV, indicating that NMDA receptors play a role. Application of ZD7288, a selective inhibitor of the hyperpolarization-activated cationic current I(h), almost completely blocked the relative facilitation of responses, and the less potent I(h)-blocker Cs(+) also resulted in a partial block. The relative facilitation of synaptic responses induced by CCh is therefore likely mediated by multiple mechanisms including the cholinergic suppression of transmitter release that enhances transmitter availability during repetitive stimulation, NMDA receptor-mediated effects on pre- or postsynaptic function, and

  12. Synaptic remodeling in the dentate gyrus, CA3, CA1, subiculum, and entorhinal cortex of mice: effects of deprived rearing and voluntary running.

    PubMed

    Schaefers, Andrea T U; Grafen, Keren; Teuchert-Noodt, Gertraud; Winter, York

    2010-01-01

    Hippocampal cell proliferation is strongly increased and synaptic turnover decreased after rearing under social and physical deprivation in gerbils (Meriones unguiculatus). We examined if a similar epigenetic effect of rearing environment on adult neuroplastic responses can be found in mice (Mus musculus). We examined synaptic turnover rates in the dentate gyrus, CA3, CA1, subiculum, and entorhinal cortex. No direct effects of deprived rearing on rates of synaptic turnover were found in any of the studied regions. However, adult wheel running had the effect of leveling layer-specific differences in synaptic remodeling in the dentate gyrus, CA3, and CA1, but not in the entorhinal cortex and subiculum of animals of both rearing treatments. Epigenetic effects during juvenile development affected adult neural plasticity in mice, but seemed to be less pronounced than in gerbils.

  13. Synaptic Remodeling in the Dentate Gyrus, CA3, CA1, Subiculum, and Entorhinal Cortex of Mice: Effects of Deprived Rearing and Voluntary Running

    PubMed Central

    Schaefers, Andrea T. U.; Grafen, Keren; Teuchert-Noodt, Gertraud; Winter, York

    2010-01-01

    Hippocampal cell proliferation is strongly increased and synaptic turnover decreased after rearing under social and physical deprivation in gerbils (Meriones unguiculatus). We examined if a similar epigenetic effect of rearing environment on adult neuroplastic responses can be found in mice (Mus musculus). We examined synaptic turnover rates in the dentate gyrus, CA3, CA1, subiculum, and entorhinal cortex. No direct effects of deprived rearing on rates of synaptic turnover were found in any of the studied regions. However, adult wheel running had the effect of leveling layer-specific differences in synaptic remodeling in the dentate gyrus, CA3, and CA1, but not in the entorhinal cortex and subiculum of animals of both rearing treatments. Epigenetic effects during juvenile development affected adult neural plasticity in mice, but seemed to be less pronounced than in gerbils. PMID:20508828

  14. Examination of rhythmicity of extracellularly recorded neurons in the entorhinal cortex

    PubMed Central

    Climer, Jason R.; DiTullio, Ronald; Newman, Ehren L.; Hasselmo, Michael E.; Eden, Uri T.

    2015-01-01

    A number of studies have examined the theta-rhythmic modulation of neuronal firing in the hippocampal circuit. For extracellular recordings, this is often done by examining spectral properties of the spike-time autocorrelogram, most significantly, for validating the presence or absence of theta modulation across species. These techniques can show significant rhythmicity for high firing rate, highly rhythmic neurons; however, they are substantially biased by several factors including the peak firing rate of the neuron, the amount of time spent in the neuron’s receptive field, and other temporal properties of the rhythmicity such as cycle-skipping. These limitations make it difficult to examine rhythmic modulation in neurons with low firing rates or when an animal has short dwell times within the firing field and difficult to compare rhythmicity under disparate experimental conditions when these factors frequently differ. Here, we describe in detail the challenges that researchers face when using these techniques and apply our findings to recent recordings from bat entorhinal grid cells, suggesting that they may have lacked enough data to examine theta rhythmicity robustly. We describe a more sensitive and statistically rigorous method using maximum likelihood estimation (MLE) of a parametric model of the lags within the autocorrelation window, which helps to alleviate some of the problems of traditional methods, which was also unable to detect rhythmicity in bat grid cells. Using large batteries of simulated data, we explored the boundaries for which the MLE technique and the theta index can detect rhythmicity. The MLE technique is less sensitive to many features of the autocorrelogram, and provides a framework for statistical testing to detect rhythmicity as well as changes in rhythmicity in individual sessions providing a substantial improvement over previous methods. PMID:25331248

  15. Pyramidal and stellate cell specificity of grid and border representations in layer 2 of medial entorhinal cortex.

    PubMed

    Tang, Qiusong; Burgalossi, Andrea; Ebbesen, Christian Laut; Ray, Saikat; Naumann, Robert; Schmidt, Helene; Spicher, Dominik; Brecht, Michael

    2014-12-17

    In medial entorhinal cortex, layer 2 principal cells divide into pyramidal neurons (mostly calbindin positive) and dentate gyrus-projecting stellate cells (mostly calbindin negative). We juxtacellularly labeled layer 2 neurons in freely moving animals, but small sample size prevented establishing unequivocal structure-function relationships. We show, however, that spike locking to theta oscillations allows assigning unidentified extracellular recordings to pyramidal and stellate cells with ∼83% and ∼89% specificity, respectively. In pooled anatomically identified and theta-locking-assigned recordings, nonspatial discharges dominated, and weakly hexagonal spatial discharges and head-direction selectivity were observed in both cell types. Clear grid discharges were rare and mostly classified as pyramids (19%, 19/99 putative pyramids versus 3%, 3/94 putative stellates). Most border cells were classified as stellate (11%, 10/94 putative stellates versus 1%, 1/99 putative pyramids). Our data suggest weakly theta-locked stellate border cells provide spatial input to dentate gyrus, whereas strongly theta-locked grid discharges occur mainly in hexagonally arranged pyramidal cell patches and do not feed into dentate gyrus.

  16. The Preferred Directions of Conjunctive Grid X Head Direction Cells in the Medial Entorhinal Cortex Are Periodically Organized.

    PubMed

    Keinath, Alexander Thomas

    2016-01-01

    The discovery of speed-modulated grid, head direction, and conjunctive grid x head direction cells in the medial entorhinal cortex has led to the hypothesis that path integration, the updating of one's spatial representation based on movement, may be carried out within this region. This hypothesis has been formalized by many computational models, including a class known as attractor network models. While many of these models propose specific mechanisms by which path integration might occur, predictions of these specific mechanisms have not been tested. Here I derive and test a key prediction of one attractor network path integration mechanism. Specifically, I first demonstrate that this mechanism predicts a periodic distribution of conjunctive cell preferred directions in order to minimize drift. Next, I test whether conjunctive cell preferred directions are in fact periodically organized. Results indicate that conjunctive cells are preferentially tuned to increments of 36°, consistent with drift minimization in this path integration mechanism. By contrast, no periodicity was observed in the preferred directions of either pure grid or pure head direction cells. These results provide the first neural evidence of a nonuniform structure in the directional preferences of any head direction representation found in the brain.

  17. Distribution of the receptor-anchoring protein gephyrin in the rat dentate gyrus and changes following entorhinal cortex lesion.

    PubMed

    Simbürger, E; Plaschke, M; Kirsch, J; Nitsch, R

    2000-04-01

    We analyzed the distribution of the receptor-anchoring protein gephyrin in the normal and deafferented rat dentate gyrus to investigate whether the expression of this postsynaptic protein is altered in response to the formation of new synaptic contacts. Confocal microscopy and digital image analysis revealed that in normal dentate gyrus immunolabeling was most prominent in the outer molecular layer and decreased successively in the direction of the granule cell layer. Simultaneous immunolabeling for gephyrin and cell-specific markers showed that granule cells and parvalbumin-positive interneurons express gephyrin. Large, intensely stained, gephyrin-positive clusters were distributed along distinct dendrites, and most of them were positive for parvalbumin. Calbindin-immunostained dendrites were associated with smaller, gephyrin-positive clusters. Lesion of the medial entorhinal cortex leads to deafferentiation of the middle molecular layer which resulted in an increased gephyrin immunoreactivity. These changes were due to a significantly increased concentration of the very small gephyrin-positive clusters. Parvalbumin-positive dendrites did not display any increase in co-localizing gephyrin-positive structures. The altered immunolabeling pattern persisted until 12 weeks after lesion, a time when the process of synaptic reorganization is complete. Our findings suggest that synaptogenesis following deafferentiation results in a cell-specific redistribution of gephyrin immunoreactivity at specific inhibitory synapses.

  18. Developmental iodine deficiency and hypothyroidism reduce phosphorylation of calcium/calmodulin-dependent kinase II in the rat entorhinal cortex.

    PubMed

    Wang, Yi; Hou, Yi; Dong, Jing; Xu, Hongde; Gong, Jian; Chen, Jie

    2010-12-01

    Iodine is essential for the synthesis of triiodothyronine (T₃) and thyroxine (T₄). Iodine deficiency leads to inadequate thyroid hormone. Hypothyroidism induced by iodine deficiency during gestation and postnatal period leads to cognitive deficits in learning and memory. However, the mechanism underlying these deficits is unclear. Calcium-dependent calmodulin kinase II (CaMKII) known as a potential memory molecule regulates important neuronal functions including learning and memory. Recent studies have shown that hypothyroidism alters phosphorylation of CaMKII in hippocampus or even in sympathetic ganglia of rats. Though the entorhinal cortex (EC) is an important functional structure within the neuronal network responsible for learning and memory, little is known about the effect of hypothyroidism on phosphorylation of CaMKII in the EC. Here, we report that iodine deficiency and propylthiouracil treatment through gestation and lactation reduce phosphorylation of CaMKII in the EC of pups. The increase of calcineurin, as well as reduction of neurogranin and calmodulin, may account for the reduced phosphorylation of CaMKII induced by developmental iodine deficiency and hypothyroidism. These findings in the EC may contribute to understanding the mechanisms that underlie impairment of learning and memory induced by developmental iodine deficiency and hypothyroidism.

  19. Gastrodin Suppresses the Amyloid β-Induced Increase of Spontaneous Discharge in the Entorhinal Cortex of Rats

    PubMed Central

    Chen, Peng-zhi; Jiang, Hui-hui; Wen, Bo; Ren, Shuan-cheng; Chen, Yang; Ji, Wei-gang; Hu, Bo; Zhang, Jun; Xu, Fenglian; Zhu, Zhi-ru

    2014-01-01

    Accumulated soluble amyloid beta- (Aβ-) induced aberrant neuronal network activity may directly contribute to cognitive deficits, which are the most outstanding characteristics of Alzheimer's disease (AD). The entorhinal cortex (EC) is one of the earliest affected brain regions in AD. Impairments of EC neurons are responsible for the cognitive deficits in AD. However, little effort has been made to investigate the effects of soluble Aβ on the discharge properties of EC neurons in vivo. The present study was designed to examine the effects of soluble Aβ1−42 on the discharge properties of EC neurons, using in vivo extracellular single unit recordings. The protective effects of gastrodin (GAS) were also investigated against Aβ1−42-induced alterations in EC neuronal activities. The results showed that the spontaneous discharge of EC neurons was increased by local application of soluble Aβ1−42 and that GAS can effectively reverse Aβ1−42-induced facilitation of spontaneous discharge in a concentration-dependent manner. Moreover, whole-cell patch clamp results indicated that the protective function of GAS on abnormal hyperexcitability may be partially mediated by its inhibitory action on Aβ1−42-elicited inward currents in EC neurons. Our study suggested that GAS may provide neuroprotective effects on Aβ1−42-induced hyperactivity in EC neurons of rats. PMID:25485157

  20. DHA Improves Cognition and Prevents Dysfunction of Entorhinal Cortex Neurons in 3xTg-AD Mice

    PubMed Central

    Arsenault, Dany; Julien, Carl; Tremblay, Cyntia; Calon, Frédéric

    2011-01-01

    Defects in neuronal activity of the entorhinal cortex (EC) are suspected to underlie the symptoms of Alzheimer's disease (AD). Whereas neuroprotective effects of docosahexaenoic acid (DHA) have been described, the effects of DHA on the physiology of EC neurons remain unexplored in animal models of AD. Here, we show that DHA consumption improved object recognition (↑12%), preventing deficits observed in old 3xTg-AD mice (↓12%). Moreover, 3xTg-AD mice displayed seizure-like akinetic episodes, not detected in NonTg littermates and partly prevented by DHA (↓50%). Patch-clamp recording revealed that 3xTg-AD EC neurons displayed (i) loss of cell capacitance (CC), suggesting reduced membrane surface area; (ii) increase of firing rate versus injected current (F-I) curve associated with modified action potentials, and (iii) overactivation of glutamatergic synapses, without changes in synaptophysin levels. DHA consumption increased CC (↑12%) and decreased F-I slopes (↓21%), thereby preventing the opposite alterations observed in 3xTg-AD mice. Our results indicate that cognitive performance and basic physiology of EC neurons depend on DHA intake in a mouse model of AD. PMID:21383850

  1. Sequential expression of cell-cycle regulators and Alzheimer's disease-related proteins in entorhinal cortex after hippocampal excitotoxic damage.

    PubMed

    Hernández-Ortega, Karina; Ferrera, Patricia; Arias, Clorinda

    2007-06-01

    Growing evidence suggests that one of the earliest events in the neuronal degeneration of Alzheimer's disease (AD) is aberrant cell-cycle activation in postmitotic neurons, which may, in fact, be sufficient to initiate the neurodegenerative cascade. In the present study we examined whether cyclins and cyclin-dependent kinases, molecules normally associated with cell-cycle control, may be involved in delayed expression of altered Alzheimer's proteins in two interconnected areas, the entorhinal cortex (EC) and the dentate gyrus (DG), after a hippocampal excitotoxic lesion. Several cell-cycle proteins of the G1 and S phases and even of the G2 phase were found to be up-regulated in the EC after kainic acid evoked neuronal death in the hippocampus. In addition, we describe the progressive expression of two Alzheimer's-related proteins, PHF-1 and APP, which reached higher levels immediately after the increase in G1/S-phase markers. Hence, the results of the present study support the participation of cell-cycle dysregulation as a key component of the process that may ultimately lead to expression of AD proteins and neuronal death in a brain area when the target site for synaptic inputs in that area is damaged by an excitotoxic insult. Copyright (c) 2007 Wiley-Liss, Inc.

  2. Distant Space Processing is Controlled by tPA-dependent NMDA Receptor Signaling in the Entorhinal Cortex.

    PubMed

    Hébert, Marie; Anfray, Antoine; Chevilley, Arnaud; Martinez de Lizarrondo, Sara; Quenault, Aurélien; Louessard, Morgane; Roussel, Benoit D; Obiang, Pauline; Save, Etienne; Orset, Cyrille; Maubert, Eric; Vivien, Denis; Agin, Véronique

    2017-10-01

    In humans, spatial cognition and navigation impairments are a frequent situation during physiological and pathological aging, leading to a dramatic deterioration in the quality of life. Despite the discovery of neurons with location-specific activity in rodents, that is, place cells in the hippocampus and later on grid cells in the entorhinal cortex (EC), the molecular mechanisms underlying spatial cognition are still poorly known. Our present data bring together in an unusual combination 2 molecules of primary biological importance: a major neuronal excitatory receptor, N-methyl-D-aspartate receptor (NMDAR), and an extracellular protease, tissue plasminogen activator (tPA), in the control of spatial navigation. By using tPA-deficient mice and a structure-selective pharmacological approach, we demonstrate that the tPA-dependent NMDAR signaling potentiation in the EC plays a key and selective role in the encoding and the subsequent use of distant landmarks during spatial learning. We also demonstrate that this novel function of tPA in the EC is reduced during aging. Overall, these results argue for the concept that encoding of proximal versus distal landmarks is mediated not only by different anatomical pathways but also by different molecular mechanisms, with the tPA-dependent potentiation of NMDAR signaling in the EC that plays an important role. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  3. Entorhinal Cortex dysfunction can be rescued by inhibition of microglial RAGE in an Alzheimer’s disease mouse model

    PubMed Central

    Criscuolo, Chiara; Fontebasso, Veronica; Middei, Silvia; Stazi, Martina; Ammassari-Teule, Martine; Yan, Shirley ShiDu; Origlia, Nicola

    2017-01-01

    The Entorhinal cortex (EC) has been implicated in the early stages of Alzheimer’s disease (AD). In particular, spreading of neuronal dysfunction within the EC-Hippocampal network has been suggested. We have investigated the time course of EC dysfunction in the AD mouse model carrying human mutation of amyloid precursor protein (mhAPP) expressing human Aβ. We found that in mhAPP mice plasticity impairment is first observed in EC superficial layer and further affected with time. A selective impairment of LTP was observed in layer II horizontal connections of EC slices from 2 month old mhAPP mice, whereas at later stage of neurodegeneration (6 month) basal synaptic transmission and LTD were also affected. Accordingly, early synaptic deficit in the mhAPP mice were associated with a selective impairment in EC-dependent associative memory tasks. The introduction of the dominant-negative form of RAGE lacking RAGE signalling targeted to microglia (DNMSR) in mhAPP mice prevented synaptic and behavioural deficit, reducing the activation of stress related kinases (p38MAPK and JNK). Our results support the involvement of the EC in the development and progression of the synaptic and behavioural deficit during amyloid-dependent neurodegeneration and demonstrate that microglial RAGE activation in presence of Aβ-enriched environment contributes to the EC vulnerability. PMID:28205565

  4. Visual landmarks sharpen grid cell metric and confer context specificity to neurons of the medial entorhinal cortex

    PubMed Central

    Pérez-Escobar, José Antonio; Kornienko, Olga; Latuske, Patrick; Kohler, Laura; Allen, Kevin

    2016-01-01

    Neurons of the medial entorhinal cortex (MEC) provide spatial representations critical for navigation. In this network, the periodic firing fields of grid cells act as a metric element for position. The location of the grid firing fields depends on interactions between self-motion information, geometrical properties of the environment and nonmetric contextual cues. Here, we test whether visual information, including nonmetric contextual cues, also regulates the firing rate of MEC neurons. Removal of visual landmarks caused a profound impairment in grid cell periodicity. Moreover, the speed code of MEC neurons changed in darkness and the activity of border cells became less confined to environmental boundaries. Half of the MEC neurons changed their firing rate in darkness. Manipulations of nonmetric visual cues that left the boundaries of a 1D environment in place caused rate changes in grid cells. These findings reveal context specificity in the rate code of MEC neurons. DOI: http://dx.doi.org/10.7554/eLife.16937.001 PMID:27449281

  5. State-dependent modulation of amygdala inputs by dopamine-induced enhancement of sodium currents in layer V entorhinal cortex.

    PubMed

    Rosenkranz, J Amiel; Johnston, Daniel

    2007-06-27

    Interaction between the entorhinal cortex (EC) and basolateral amygdala (BLA) may be a fundamental component in the consolidation of many forms of affective memory, such as inhibitory avoidance. Dopamine (DA) in the EC is necessary for, and may facilitate, this form of learning. This effect of DA on affective behaviors may be accomplished in part through modulation of amygdala inputs. Although it is known that DA can modulate neuronal activity in the EC, it is not known whether DA modulates inputs from the BLA. In this study, we used in vitro patch-clamp recordings and Ca2+ imaging of layer V neurons in the rat lateral EC to determine whether DA modulates the integration of inputs from the BLA and the mechanism for this modulation. We found that DA exerted actions that depended on the neuronal state. Near resting membrane potentials, DA suppressed integration of inputs, whereas at depolarized potentials, DA enhanced integration. DA enhanced the integration by a D2-mediated enhancement of Na+ currents, via phospholipase C. These experiments demonstrate that DA can exert actions in the EC that depend on the membrane voltage. This effect of DA may affect a wide range of inputs. Functionally, by enhancement of amygdala inputs that arrive in concert with other inputs, or during depolarized states, DA can facilitate the impact of affect on memory in a subset of conditions.

  6. Fimbria-fornix and entorhinal cortex differential contribution to contextual and cued fear conditioning consolidation in rats.

    PubMed

    Baldi, Elisabetta; Liuzzo, Antonino; Bucherelli, Corrado

    2013-04-10

    The Fimbria-Fornix (FF) and Entorhinal Cortex (EC) are the primary interfaces between the hippocampus and, respectively, subcortical structures and cortical areas. Their mnemonic role has been repeatedly proposed. In order to investigate their role in fear conditioning, FF and EC were subjected to bilateral fully reversible tetrodotoxin (TTX) inactivation during consolidation in adult male Wistar rats that had undergone training for fear conditioning to an acoustic stimulus (CS) and context. TTX was stereotaxically injected into animals of different groups at increasing post-acquisition delays. Memory was assessed as conditioned freezing duration measured during retention testing, performed 72 and 96 h after TTX administration in a counterbalanced manner. The results showed that FF inactivation, performed immediately after conditioning, did not disrupt consolidation of either contextual or auditory fear memory. On the contrary, EC inactivation performed at the same time was followed by both contextual and CS fear response retention impairment. EC inactivation performed 1.5h post-acquisition impaired only contextual fear response retention. EC inactivation performed 24h after acquisition training had no effect on the consolidation process. The present findings show a clearly different role of FF and EC in fear conditioning consolidation in the rat. The results are discussed in relation to their known connections with the hippocampus.

  7. Regional Specific Evidence for Memory-Load Dependent Activity in the Dorsal Subiculum and the Lateral Entorhinal Cortex

    PubMed Central

    Ku, Shih-pi; Nakamura, Nozomu H.; Maingret, Nicolas; Mahnke, Liv; Yoshida, Motoharu; Sauvage, Magdalena M.

    2017-01-01

    The subiculum and the lateral entorhinal cortex (LEC) are the main output areas of the hippocampus which contribute to spatial and non-spatial memory. The proximal part of the subiculum (bordering CA1) receives heavy projections from the perirhinal cortex and the distal part of CA1 (bordering the subiculum), both known for their ties to object recognition memory. However, the extent to which the proximal subiculum contributes to non-spatial memory is still unclear. Comparatively, the involvement of the LEC in non-spatial information processing is quite well known. However, very few studies have investigated its role within the frame of memory function. Thus, it is not known whether its contribution depends on memory load. In addition, the deep layers of the EC have been shown to be predictive of subsequent memory performance, but not its superficial layers. Hence, here we tested the extent to which the proximal part of the subiculum and the superficial and deep layers of the LEC contribute to non-spatial memory, and whether this contribution depends on the memory load of the task. To do so, we imaged brain activity at cellular resolution in these areas in rats performing a delayed nonmatch to sample task based on odors with two different memory loads (5 or 10 odors). This imaging technique is based on the detection of the RNA of the immediate-early gene Arc, which is especially tied to synaptic plasticity and behavioral demands, and is commonly used to map activity in the medial temporal lobe. We report for the first time that the proximal part of the subiculum is recruited in a memory-load dependent manner and the deep layers of the LEC engaged under high memory load conditions during the retrieval of non-spatial memory, thus shedding light on the specific networks contributing to non-spatial memory retrieval. PMID:28790897

  8. Activation of Phosphatidylinositol-Linked Dopamine Receptors Induces a Facilitation of Glutamate-Mediated Synaptic Transmission in the Lateral Entorhinal Cortex

    PubMed Central

    Glovaci, Iulia; Chapman, C. Andrew

    2015-01-01

    The lateral entorhinal cortex receives strong inputs from midbrain dopamine neurons that can modulate its sensory and mnemonic function. We have previously demonstrated that 1 µM dopamine facilitates synaptic transmission in layer II entorhinal cortex cells via activation of D1-like receptors, increased cAMP-PKA activity, and a resulting enhancement of AMPA-receptor mediated currents. The present study assessed the contribution of phosphatidylinositol (PI)-linked D1 receptors to the dopaminergic facilitation of transmission in layer II of the rat entorhinal cortex, and the involvement of phospholipase C activity and release of calcium from internal stores. Whole-cell patch-clamp recordings of glutamate-mediated evoked excitatory postsynaptic currents were obtained from pyramidal and fan cells. Activation of D1-like receptors using SKF38393, SKF83959, or 1 µM dopamine induced a reversible facilitation of EPSCs which was abolished by loading cells with either the phospholipase C inhibitor U-73122 or the Ca2+ chelator BAPTA. Neither the L-type voltage-gated Ca2+ channel blocker nifedipine, nor the L/N-type channel blocker cilnidipine, blocked the facilitation of synaptic currents. However, the facilitation was blocked by blocking Ca2+ release from internal stores via inositol 1,4,5-trisphosphate (InsP3) receptors or ryanodine receptors. Follow-up studies demonstrated that inhibiting CaMKII activity with KN-93 failed to block the facilitation, but that application of the protein kinase C inhibitor PKC(19-36) completely blocked the dopamine-induced facilitation. Overall, in addition to our previous report indicating a role for the cAMP-PKA pathway in dopamine-induced facilitation of synaptic transmission, we demonstrate here that the dopaminergic facilitation of synaptic responses in layer II entorhinal neurons also relies on a signaling cascade dependent on PI-linked D1 receptors, PLC, release of Ca2+ from internal stores, and PKC activation which is likely dependent

  9. Aberrant Sodium Channel Currents and Hyperexcitability of Medial Entorhinal Cortex Neurons in a Mouse Model of SCN8A Encephalopathy.

    PubMed

    Ottolini, Matteo; Barker, Bryan S; Gaykema, Ronald P; Meisler, Miriam H; Patel, Manoj K

    2017-08-09

    SCN8A encephalopathy, or early infantile epileptic encephalopathy 13 (EIEE13), is caused predominantly by de novo gain-of-function mutations in the voltage-gated Na channel Nav1.6. Affected individuals suffer from refractory seizures, developmental delay, cognitive disability, and elevated risk of sudden unexpected death in epilepsy (SUDEP). A knock-in mouse model carrying the patient mutation p.Asn1768Asp (N1768D) reproduces many features of the disorder, including spontaneous seizures and SUDEP. We used the mouse model to examine the effects of the mutation on layer II stellate neurons of the medial entorhinal cortex (mEC), which transmit excitatory input to the hippocampus. Heterozygous (Scn8a(D/+)), homozygous (Scn8a(D/D))), and WT (Scn8a(+/+)) littermates were compared at 3 weeks of age, the time of seizure onset for homozygous mice. Heterozygotes remain seizure free for another month. mEC layer II neurons of heterozygous and homozygous mice were hyperexcitable and generated long-lasting depolarizing potentials with bursts of action potentials after synaptic stimulation. Recording of Na currents revealed proexcitatory increases in persistent and resurgent currents and rightward shifts in inactivation parameters, leading to significant increases in the magnitude of window currents. The proexcitatory changes were more pronounced in homozygous mice than in heterozygotes, consistent with the earlier age of seizure onset in homozygotes. These studies demonstrate that the N1768D mutation increases the excitability of mEC layer II neurons by increasing persistent and resurgent Na currents and disrupting channel inactivation. The aberrant activities of mEC layer II neurons would provide excessive excitatory input to the hippocampus and contribute to hyperexcitability of hippocampal neurons in this model of SCN8A encephalopathy.SIGNIFICANCE STATEMENTSCN8A encephalopathy is a devastating neurological disorder that results from de novo mutations in the Na channel Nav1

  10. Temporal Lobe Epilepsy Induces Intrinsic Alterations in Na Channel Gating in Layer II Medial Entorhinal Cortex Neurons

    PubMed Central

    Hargus, Nicholas J.; Merrick, Ellen C.; Nigam, Aradhya; Kalmar, Christopher L.; Baheti, Aparna R.; Bertram, Edward H.; Patel, Manoj K.

    2010-01-01

    Temporal lobe epilepsy (TLE) is the most common form of adult epilepsy involving the limbic structures of the temporal lobe. Layer II neurons of the entorhinal cortex (EC) form the major excitatory input into the hippocampus via the perforant path and consist of non-stellate and stellate neurons. These neurons are spared and hyper-excitable in TLE. The basis for the hyper-excitability is likely multifactorial and may include alterations in intrinsic properties. In a rat model of TLE, medial EC (mEC) non-stellate and stellate neurons had significantly higher action potential (AP) firing frequencies than in control. The increase remained in the presence of synaptic blockers, suggesting intrinsic mechanisms. Since sodium (Na) channels play a critical role in AP generation and conduction we sought to determine if Na channel gating parameters and expression levels were altered in TLE. Na channel currents recorded from isolated mEC TLE neurons revealed increased Na channel conductances, depolarizing shifts in inactivation parameters and larger persistent (INaP) and resurgent (INaR) Na currents. Immunofluorescence experiments revealed increased staining of Nav1.6 within the axon initial segment and Nav1.2 within the cell bodies of mEC TLE neurons. These studies provide support for additional intrinsic alterations within mEC layer II neurons in TLE and implicate alterations in Na channel activity and expression, in part, for establishing the profound increase in intrinsic membrane excitability of mEC layer II neurons in TLE. These intrinsic changes, together with changes in the synaptic network, could support seizure activity in TLE. PMID:20946956

  11. Target-Selectivity of Parvalbumin-Positive Interneurons in Layer II of Medial Entorhinal Cortex in Normal and Epileptic Animals

    PubMed Central

    Armstrong, Caren; Wang, Jessica; Lee, Soo Yeun; Broderick, John; Bezaire, Marianne J; Lee, Sang-Hun; Soltesz, Ivan

    2015-01-01

    The medial entorhinal cortex layer II (MEClayerII) is a brain region critical for spatial navigation and memory, and it also demonstrates a number of changes in patients with, and animal models of, temporal lobe epilepsy (TLE). Prior studies of GABAergic microcircuitry in MEClayerII revealed that cholecystokinin-containing basket cells (CCKBCs) select their targets on the basis of the long-range projection pattern of the postsynaptic principal cell. Specifically, CCKBCs largely avoid reelin-containing principal cells that form the perforant path to the ipsilateral dentate gyrus and preferentially innervate non-perforant path forming calbindin-containing principal cells. We investigated whether parvalbumin containing basket cells (PVBCs), the other major perisomatic targeting GABAergic cell population, demonstrate similar postsynaptic target selectivity as well. In addition, we tested the hypothesis that the functional or anatomic arrangement of circuit selectivity is disrupted in MEClayerII in chronic TLE, using the repeated low-dose kainate model in rats. In control animals, we found that PVBCs innervated both principal cell populations, but also had significant selectivity for calbindin-containing principal cells in MEClayerII. However, the magnitude of this preference was smaller than for CCKBCs. In addition, axonal tracing and paired recordings showed that individual PVBCs were capable of contacting both calbindin and reelin-containing principal cells. In chronically epileptic animals, we found that the intrinsic properties of the two principal cell populations, the GABAergic perisomatic bouton numbers, and selectivity of the CCKBCs and PVBCs remained remarkably constant in MEClayerII. However, miniature IPSC frequency was decreased in epilepsy, and paired recordings revealed the presence of direct excitatory connections between principal cells in the MEClayerII in epilepsy, which is unusual in normal adult MEClayerII. Taken together, these findings advance our

  12. Defects in the medial entorhinal cortex and dentate gyrus in the mouse model of Sanfilippo syndrome type B.

    PubMed

    Ohmi, Kazuhiro; Zhao, Hui-Zhi; Neufeld, Elizabeth F

    2011-01-01

    Sanfilippo syndrome type B (MPS IIIB) is characterized by profound mental retardation in childhood, dementia and death in late adolescence; it is caused by deficiency of α-N-acetylglucosaminidase and resulting lysosomal storage of heparan sulfate. A mouse model, generated by homologous recombination of the Naglu gene, was used to study pathological changes in the brain. We found earlier that neurons in the medial entorhinal cortex (MEC) and the dentate gyrus showed a number of secondary defects, including the presence of hyperphosphorylated tau (Ptau) detected with antibodies raised against Ptau in Alzheimer disease brain. By further use of immunohistochemistry, we now show staining in neurons of the same area for beta amyloid, extending the resemblance to Alzheimer disease. Ptau inclusions in the dentate gyrus of MPS IIIB mice were reduced in number when the mice were administered LiCl, a specific inhibitor of Gsk3β. Additional proteins found elevated in MEC include proteins involved in autophagy and the heparan sulfate proteoglycans, glypicans 1 and 5, the latter closely related to the primary defect. The level of secondary accumulations was associated with elevation of glypican, as seen by comparing brains of mice at different ages or with different mucopolysaccharide storage diseases. The MEC of an MPS IIIA mouse had the same intense immunostaining for glypican 1 and other markers as MPS IIIB, while MEC of MPS I and MPS II mice had weak staining, and MEC of an MPS VI mouse had no staining at all for the same proteins. A considerable amount of glypican was found in MEC of MPS IIIB mice outside of lysosomes. We propose that it is the extralysosomal glypican that would be harmful to neurons, because its heparan sulfate branches could potentiate the formation of Ptau and beta amyloid aggregates, which would be toxic as well as difficult to degrade.

  13. Contrasting patterns of receptive field plasticity in the hippocampus and the entorhinal cortex: an adaptive filtering approach.

    PubMed

    Frank, Loren M; Eden, Uri T; Solo, Victor; Wilson, Matthew A; Brown, Emery N

    2002-05-01

    Neural receptive fields are frequently plastic: a neural response to a stimulus can change over time as a result of experience. We developed an adaptive point process filtering algorithm that allowed us to estimate the dynamics of both the spatial receptive field (spatial intensity function) and the interspike interval structure (temporal intensity function) of neural spike trains on a millisecond time scale without binning over time or space. We applied this algorithm to both simulated data and recordings of putative excitatory neurons from the CA1 region of the hippocampus and the deep layers of the entorhinal cortex (EC) of awake, behaving rats. Our simulation results demonstrate that the algorithm accurately tracks simultaneous changes in the spatial and temporal structure of the spike train. When we applied the algorithm to experimental data, we found consistent patterns of plasticity in the spatial and temporal intensity functions of both CA1 and deep EC neurons. These patterns tended to be opposite in sign, in that the spatial intensity functions of CA1 neurons showed a consistent increase over time, whereas those of deep EC neurons tended to decrease, and the temporal intensity functions of CA1 neurons showed a consistent increase only in the "theta" (75-150 msec) region, whereas those of deep EC neurons decreased in the region between 20 and 75 msec. In addition, the minority of deep EC neurons whose spatial intensity functions increased in area over time fired in a significantly more spatially specific manner than non-increasing deep EC neurons. We hypothesize that this subset of deep EC neurons may receive more direct input from CA1 and may be part of a neural circuit that transmits information about the animal's location to the neocortex.

  14. Differential role of muscarinic transmission within the entorhinal cortex and basolateral amygdala in the processing of irrelevant stimuli.

    PubMed

    Barak, Segev; Weiner, Ina

    2010-04-01

    Cholinergic projections to the entorhinal cortex (EC) and basolateral amygdala (BLA) mediate distinct cognitive processes through muscarinic acetylcholine receptors (mAChRs). In this study, we sought to further differentiate the role of muscarinic transmission in these regions in cognition, using the latent inhibition (LI) phenomenon. LI is a cross-species phenomenon manifested as poorer conditioning to a stimulus experienced as irrelevant during an earlier stage of repeated non-reinforced pre-exposure to that stimulus, and is considered to index the ability to ignore, or to in-attend to, irrelevant stimuli. Given our recent findings that systemic administration of the mAChR antagonist scopolamine can produce two contrasting LI abnormalities in rats, ie, abolish LI under conditions yielding LI in non-treated controls, or produce abnormally persistent LI under conditions preventing its expression in non-treated controls, we tested whether mAChR blockade in the EC and BLA would induce LI abolition and persistence, respectively. We found that intra-EC scopolamine infusion (1, 10 mug per hemisphere) abolished LI when infused in pre-exposure or both pre-exposure and conditioning, but not in conditioning alone, whereas intra-BLA scopolamine infusion led to persistent LI when infused in conditioning or both stages, but not in pre-exposure alone. Although cholinergic innervation of the EC and BLA has long been implicated in attention to novel stimuli and in processing of motivationally significant stimuli, respectively, our results provide evidence that EC mAChRs also have a role in the development of inattention to stimuli, whereas BLA mAChRs have a role in re-attending to previously irrelevant stimuli that became motivationally relevant.

  15. Reduced mitochondrial activity is early and steady in the entorhinal cortex but it is mainly unmodified in the frontal cortex in Alzheimer's disease.

    PubMed

    Armand-Ugon, Mercedes; Ansoleaga, Belen; Berjaoui, Sara; Ferrer, Isidro

    2017-05-04

    Background It is well established that mitochondrial damage plays a role in the pathophysiology of Alzheimer's disease (AD). However, studies carried out in humans barely contemplate regional differences with disease progression. Objective To study the expression of selected nuclear genes encoding subunits of the mitochondrial complexes and the activity of mitochondrial complexes in AD, in two regions: the entorhinal cortex (EC) and frontal cortex area 8 (FC). Methods Frozen samples from 148 cases processed for gene expression by qRT-PCR and determination of individual activities of mitochondrial complexes I, II, IV and V using commercial kits and home-made assays. Results Decreased expression of NDUFA2, NDUFB3, UQCR11, COX7C, ATPD, ATP5L and ATP50, covering subunits of complex I, II, IV and V, occurs in total homogenates of the EC in AD stages V-VI when compared with stages I-II. However reduced activity of complexes I, II and V of isolated mitochondria occurs as early as stages I-II when compared with middle-aged individuals in the EC. In contrast, no alterations in the expression of the same genes and no alterations in the activity of mitochondrial complexes are found in the FC in the same series. Conclusion Different mechanisms of impaired energy metabolism may occur in AD, one of them, represented by the EC, is the result of primary and early alteration of mitochondria; the other one is probably the result, at least in part, of decreased functional input and is represented by hypo-metabolism in the FC in AD patients aged 86 or younger. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  16. Reversible inactivation of the entorhinal cortex disrupts the establishment and expression of latent inhibition of cued fear conditioning in C57BL/6 mice.

    PubMed

    Lewis, Michael C; Gould, Thomas J

    2007-01-01

    For latent inhibition, preexposure to a conditioned stimulus (CS) prior to training with an unconditioned stimulus (US) results in decreased conditioned responses (CRs) to the CS at the time of testing. The mechanism by which decreased CRs occurs, however, is unknown; CS preexposure may interfere with subsequent conditioning, or modulate the expression of CRs. Previous research has suggested that the entorhinal cortex (EC) is necessary for latent inhibition of a variety of tasks. However, no studies have specifically compared the role of the EC in acquisition vs. expression of latent inhibition. The present study used reversible inactivation of the EC to address this issue. The GABA agonist muscimol (0.5 microg/side) was directly infused into the EC of mice prior to CS preexposure, training, or testing. Our results indicate that muscimol inactivation of the EC before CS preexposure disrupts latent inhibition of cued fear conditioning. Importantly, this same dose of muscimol did not disrupt cued fear conditioning, nor did it affect latent inhibition when infused into the subiculum. Furthermore, inactivation of the EC at testing disrupted the expression of latent inhibition of cued fear conditioning; that is, CS preexposed mice that received entorhinal cortical muscimol infusion at testing showed CRs compared to saline-infused CS preexposed mice. These findings suggest that repeated preexposure to the CS during latent inhibition may alter entorhinal cortical activity thereby allowing the EC to exert inhibitory control over the expression of CRs during testing of CS preexposed mice.

  17. Calretinin in the entorhinal cortex of the rat: distribution, morphology, ultrastructure of neurons, and co-localization with gamma-aminobutyric acid and parvalbumin.

    PubMed

    Wouterlood, F G; van Denderen, J C; van Haeften, T; Witter, M P

    2000-09-18

    Calretinin is a marker that differentially labels neurons in the central nervous system. We used this marker to distinguish subtypes of neurons within the general population of neurons in the entorhinal cortex of the rat. The distribution, morphology, and ultrastructure of calretinin-immunopositive neurons in this cortical area were documented. We further analyzed the co-localization of the marker with gamma-aminobutyric acid (GABA) and studied whether calretinin-positive neurons project to the hippocampal formation. Methods used included single-label immunocytochemistry at the light and electron microscopic level, retrograde tracing combined with immunocytochemistry, and double-label confocal laser scanning microscopy (CLSM). The entorhinal cortex contained calretinin-positive cells in a scattered fashion, in all layers except layer IV (lamina dissecans). Bipolar and multipolar dendritic configurations were present, displaying smooth dendrites. Bipolar cells had a uniform morphology whereas the multipolar calretinin cell population consisted of large neurons, cells with long ascending dendrites, horizontally oriented neurons, and small spherical cells. Retrograde tracing combined with immunocytochemistry showed that calretinin is not present in cells projecting to the hippocampus. Few synapic contacts between calretinin-positive axon terminals and immunopositive cell bodies and dendrites were seen. Most axon terminals of calretinin fibers formed asymmetrical synapses, and immunopositive axons were always unmyelinated. Results obtained in the CLSM indicate that calretinin co-exists in only 18-20% of the GABAergic cell population (mostly small spherical and bipolar cells). Thus, the entorhinal cortex contains two classes of calretinin interneurons: GABA positive and GABA negative. The first class is presumably a classical, GABAergic inhibitory interneuron. The finding of calretinin-immunoreactive axon terminals with asymmetrical synapses suggests that the second

  18. Impact of Continuous Versus Discontinuous Progesterone on Estradiol Regulation of Neuron Viability and Sprouting After Entorhinal Cortex Lesion in Female Rats

    PubMed Central

    Barron, Anna M.; Brown, Meghan A.; Morgan, Todd E.

    2015-01-01

    Because the estrogen-based hormone therapy (HT) in postmenopausal women typically contains a progestogen component, understanding the interactions between estrogens and progestogens is critical for optimizing the potential neural benefits of HT. An important issue in this regard is the use of continuous vs discontinuous hormone treatments. Although sex steroid hormone levels naturally exhibit cyclic fluctuation, many HT formulations include continuous delivery of hormones. Recent findings from our laboratory and others have shown that coadministration of progesterone (P4) can either attenuate or augment beneficial actions of 17β-estradiol (E2) in experimental models depending in part upon the delivery schedule of P4. In this study, we demonstrate that the P4 delivery schedule in combined E2 and P4 treatments alters degenerative and regenerative outcomes of unilateral entorhinal cortex lesion. We assessed how lesion-induced degeneration of layer II neurons in entorhinal cortex layer and deafferentation in dentate gyrus are affected by ovariectomy and treatments with E2 alone or in combination with either continuous or discontinuous P4. Our results demonstrate the combined efficacy of E2 and P4 is dependent on the administration regimen. Importantly, the discontinuous-combined E2+P4 regimen had the greatest neuroprotective efficacy for both end points. These data extend a growing literature that indicates qualitative differences in the neuroprotective effects of E2 as a function of cotreatment with continuous versus discontinuous P4, the understanding of which has important implications for HT in postmenopausal women. PMID:25514084

  19. Effect of Prenatal Protein Malnutrition on Long-Term Potentiation and BDNF Protein Expression in the Rat Entorhinal Cortex after Neocortical and Hippocampal Tetanization

    PubMed Central

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

    2008-01-01

    Reduction of the protein content from 25 to 8% casein in the diet of pregnant rats results in impaired neocortical long-term potentiation (LTP) of the offspring together with lower visuospatial memory performance. The present study was aimed to investigate whether this type of maternal malnutrition could result in modification of plastic capabilities of the entorhinal cortex (EC) in the adult progeny. Unlike normal eutrophic controls, 55–60-day-old prenatally malnourished rats were unable to develop LTP in the medial EC to tetanizing stimulation delivered to either the ipsilateral occipital cortex or the CA1 hippocampal region. Tetanizing stimulation of CA1 also failed to increase the concentration of brain-derived neurotrophic factor (BDNF) in the EC of malnourished rats. Impaired capacity of the EC of prenatally malnourished rats to develop LTP and to increase BDNF levels during adulthood may be an important factor contributing to deficits in learning performance having adult prenatally malnourished animals. PMID:18604298

  20. Effect of prenatal protein malnutrition on long-term potentiation and BDNF protein expression in the rat entorhinal cortex after neocortical and hippocampal tetanization.

    PubMed

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

    2008-01-01

    Reduction of the protein content from 25 to 8% casein in the diet of pregnant rats results in impaired neocortical long-term potentiation (LTP) of the offspring together with lower visuospatial memory performance. The present study was aimed to investigate whether this type of maternal malnutrition could result in modification of plastic capabilities of the entorhinal cortex (EC) in the adult progeny. Unlike normal eutrophic controls, 55-60-day-old prenatally malnourished rats were unable to develop LTP in the medial EC to tetanizing stimulation delivered to either the ipsilateral occipital cortex or the CA1 hippocampal region. Tetanizing stimulation of CA1 also failed to increase the concentration of brain-derived neurotrophic factor (BDNF) in the EC of malnourished rats. Impaired capacity of the EC of prenatally malnourished rats to develop LTP and to increase BDNF levels during adulthood may be an important factor contributing to deficits in learning performance having adult prenatally malnourished animals.

  1. Sequel of spontaneous seizures after kainic acid-induced status epilepticus and associated neuropathological changes in the subiculum and entorhinal cortex

    PubMed Central

    Drexel, Meinrad; Preidt, Adrian Patrick; Sperk, Günther

    2012-01-01

    Injection of the seaweed toxin kainic acid (KA) in rats induces a severe status epilepticus initiating complex neuropathological changes in limbic brain areas and subsequently spontaneous recurrent seizures. Although neuropathological changes have been intensively investigated in the hippocampus proper and the dentate gyrus in various seizure models, much less is known about changes in parahippocampal areas. We now established telemetric EEG recordings combined with continuous video monitoring to characterize the development of spontaneous seizures after KA-induced status epilepticus, and investigated associated neurodegenerative changes, astrocyte and microglia proliferation in the subiculum and other parahippocampal brain areas. The onset of spontaneous seizures was heterogeneous, with an average latency of 15 ± 1.4 days (range 3–36 days) to the initial status epilepticus. The frequency of late spontaneous seizures was higher in rats in which the initial status epilepticus was recurrent after its interruption with diazepam compared to rats in which this treatment was more efficient. Seizure-induced neuropathological changes were assessed in the subiculum by losses in NeuN-positive neurons and by Fluoro-Jade C staining of degenerating neurons. Neuronal loss was already prominent 24 h after KA injection and only modestly progressed at the later intervals. It was most severe in the proximal subiculum and in layer III of the medial entorhinal cortex and distinct Fluoro-Jade C labeling was observed there in 75% of rats even after 3 months. Glutamatergic neurons, labeled by in situ hybridization for the vesicular glutamate transporter 1 followed a similar pattern of cell losses, except for the medial entorhinal cortex and the proximal subiculum that appeared more vulnerable. Glutamate decarboxylase65 (GAD65) mRNA expressing neurons were generally less vulnerable than glutamate neurons. Reactive astrocytes and microglia were present after 24 h, however, became

  2. Dopaminergic Modulation of GABAergic Transmission in the Entorhinal Cortex: Concerted Roles of α1 Adrenoreceptors, Inward Rectifier K+, and T-Type Ca2+ Channels

    PubMed Central

    Cilz, Nicholas I.; Kurada, Lalitha; Hu, Binqi; Lei, Saobo

    2014-01-01

    Whereas the entorhinal cortex (EC) receives profuse dopaminergic innervations from the midbrain, the effects of dopamine (DA) on γ-Aminobutyric acid (GABA)ergic interneurons in this brain region have not been determined. We probed the actions of DA on GABAA receptor-mediated synaptic transmission in the EC. Application of DA increased the frequency, not the amplitude, of spontaneous IPSCs (sIPSCs) and miniature IPSCs (mIPSCs) recorded from entorhinal principal neurons, but slightly reduced the amplitude of the evoked IPSCs. The effects of DA were unexpectedly found to be mediated by α1 adrenoreceptors, but not by DA receptors. DA endogenously released by the application of amphetamine also increased the frequency of sIPSCs. Ca2+ influx via T-type Ca2+ channels was required for DA-induced facilitation of sIPSCs and mIPSCs. DA depolarized and enhanced the firing frequency of action potentials of interneurons. DA-induced depolarization was independent of extracellular Na+ and Ca2+ and did not require the functions of hyperpolarization-activated (Ih) channels and T-type Ca2+ channels. DA-generated currents showed a reversal potential close to the K+ reversal potential and inward rectification, suggesting that DA inhibits the inward rectifier K+ channels (Kirs). Our results demonstrate that DA facilitates GABA release by activating α1 adrenoreceptors to inhibit Kirs, which further depolarize interneurons resulting in secondary Ca2+ influx via T-type Ca+ channels. PMID:23843440

  3. Dynamical organization of the cytoskeletal cortex probed by micropipette aspiration

    PubMed Central

    Brugués, Jan; Maugis, Benoit; Casademunt, Jaume; Nassoy, Pierre; Amblard, François; Sens, Pierre

    2010-01-01

    Bleb-based cell motility proceeds by the successive inflation and retraction of large spherical membrane protrusions (“blebs”) coupled with substrate adhesion. In addition to their role in motility, cellular blebs constitute a remarkable illustration of the dynamical interactions between the cytoskeletal cortex and the plasma membrane. Here we study the bleb-based motions of Entamoeba histolytica in the constrained geometry of a micropipette. We construct a generic theoretical model that combines the polymerization of an actin cortex underneath the plasma membrane with the myosin-generated contractile stress in the cortex and the stress-induced failure of membrane-cortex adhesion. One major parameter dictating the cell response to micropipette suction is the stationary cortex thickness, controlled by actin polymerization and depolymerization. The other relevant physical parameters can be combined into two characteristic cortex thicknesses for which the myosin stress (i) balances the suction pressure and (ii) provokes membrane-cortex unbinding. We propose a general phase diagram for cell motions inside a micropipette by comparing these three thicknesses. In particular, we theoretically predict and experimentally verify the existence of saltatory and oscillatory motions for a well-defined range of micropipette suction pressures. PMID:20713731

  4. The effects of combined lesions of the subicular complex and the entorhinal cortex on two forms of spatial navigation in the water maze.

    PubMed

    Oswald, C J; Good, M

    2000-02-01

    The role of the subicular complex and entorhinal cortex (SUB-EC) in spatial learning was examined in 2 water maze experiments. In Experiment 1, rats had to locate a hidden platform that was always a fixed distance and direction from an intramaze landmark. Each day, the landmark and platform were moved to a new location. Both control and SUB-EC-lesioned rats learned to locate the platform equally readily during training. However, the control group was impaired in locating the platform when the visual extramaze cues were concealed, whereas the lesioned group was unaffected by this manipulation. In Experiment 2, the lesioned rats were impaired in finding a hidden platform that was in a fixed place in the water maze and showed no evidence of having learned its location in a probe test. These results suggest that damage to the SUB-EC impairs the integration of geometric information but spares a more general navigational-directional strategy.

  5. Training in the step-down inhibitory avoidance task time-dependently increases cAMP-dependent protein kinase activity in the entorhinal cortex.

    PubMed

    Pereira, P; Ardenghi, P; Mello e Souza, T; Medina, J H; Izquierdo, I

    2001-06-01

    The cAMP/cAMP-dependent protein kinase (PKA) signaling pathway has been implicated in synaptic plasticity changes and memory consolidation. Several cortical structures are involved in the consolidation of memory for inhibitory avoidance. The aim of the present work was to observe the effects of training in the inhibitory avoidance task on the levels of PKA activity in the entorhinal, parietal and posterior cingulate cortex (EC, PARIET and PC), and the medial precentral area (Fr2) of the rat, at different post-training times (0, 1.5, 3 and 6h). PKA activity, assayed using [gamma-32P]ATP and kemptide, a selective substrate, increased in the EC 3 h after training, but no changes were observed in PARIET, PC and Fr2. These results suggest that the late phase of memory consolidation of inhibitory avoidance requires a functional PKA signaling pathway in the EC in a way that a 'peak' of PKA activity is observed.

  6. Localization of two major GABA(A) receptor subunits in the dentate gyrus of the rat and cell type-specific up-regulation following entorhinal cortex lesion.

    PubMed

    Simbürger, E; Plaschke, M; Fritschy, J M; Nitsch, R

    2001-01-01

    GABA(A) receptor subunits show a specific regional distribution in the CNS during development and in the adult animal. In the hippocampal formation, individual subsets of GABAergic interneurons are highly immunoreactive for the alpha1-subunit, whereas granule and pyramidal cells show a strong expression of the alpha2-subunit. Using confocal microscopy and digital image analysis, we demonstrate that in the dentate gyrus the alpha1-subunit immunolabeling appears in differently sized clusters. The large clusters, which are confined to dendrites of interneurons, show no alpha2 labeling, whereas the smaller ones coincide with alpha2-subunit-positive clusters. In the molecular layer, the clusters of both alpha-subunits co-localize with the anchoring protein gephyrin. In the granule cell layer and hilus, we found alpha1- and alpha2-subunit-positive clusters which were devoid of gephyrin labeling. Lesions of the medial entorhinal cortex led to the deafferentation of dendrites in the middle molecular layer of the dentate gyrus. This resulted in a significantly increased concentration of alpha2-subunit-positive clusters. We also observed an increase of alpha1-subunit immunolabeling in the deafferented area. We found no change in the co-localization between alpha1 and alpha2, and no significant change in the number of large alpha1-positive clusters along individual dendritic segments of interneurons. In a previous study, we demonstrated that calbindin-immunoreactive dendrites of granule cells revealed a significant increase in gephyrin immunoreactivity following lesion, whereas parvalbumin-positive dendrites showed no such alterations. The predominant localization of small gephyrin clusters in dendrites of granule cells, which was also described in this study, leads to the conclusion that the increase of the alpha2-subunit-positive clusters, demonstrated in the present study, indicates that, following entorhinal cortex lesion, new GABAergic synapses may be formed and that

  7. Abnormalities in the fatty acid composition of the postmortem entorhinal cortex of patients with schizophrenia, bipolar disorder, and major depressive disorder.

    PubMed

    Hamazaki, Kei; Hamazaki, Tomohito; Inadera, Hidekuni

    2013-11-30

    Previous studies of postmortem orbitofrontal cortex have shown abnormalities in levels of n-3 polyunsaturated fatty acids (PUFAs), especially docosahexaenoic acid (DHA), in individuals with schizophrenia, bipolar disorder, and major depressive disorder (MDD). We have previously measured PUFA levels in the postmortem hippocampus from patients with schizophrenia or bipolar disorder and control subjects; however, we found no significant differences between the groups except for small changes in n-6 PUFAs. Furthermore, our study of the postmortem amygdala showed no significant differences in major PUFAs in individuals with schizophrenia, bipolar disorder, or MDD in comparison with controls. In the present study, we investigated whether there were any changes in PUFAs in the entorhinal cortexes of patients with schizophrenia (n=15), bipolar disorder (n=15), or MDD (n=15) compared with unaffected controls (n=15) matched for characteristics including age and sex. In contrast to previous studies of the orbitofrontal cortex and hippocampus, we found no significant differences in major PUFAs. However, we found a 34.3% decrease in docosapentaenoic acid (DPA) (22:5n-3) in patients with MDD and an 8.7% decrease in docosatetraenoic acid (22:4n-6) in those with schizophrenia, compared with controls. Changes in PUFAs in patients with these psychiatric disorders may be specific to certain brain regions.

  8. Selective activation of parvalbumin- or somatostatin-expressing interneurons triggers epileptic seizurelike activity in mouse medial entorhinal cortex.

    PubMed

    Yekhlef, Latefa; Breschi, Gian Luca; Lagostena, Laura; Russo, Giovanni; Taverna, Stefano

    2015-03-01

    GABAergic interneurons are thought to play a critical role in eliciting interictal spikes (IICs) and triggering ictal discharges in temporal lobe epilepsy, yet the contribution of different interneuronal subtypes to seizure initiation is still largely unknown. Here we took advantage of optogenetic techniques combined with patch-clamp and field recordings to selectively stimulate parvalbumin (PV)- or somatostatin (SOM)-positive interneurons expressing channelrhodopsin-2 (CHR-2) in layers II-III of adult mouse medial entorhinal cortical slices during extracellular perfusion with the proconvulsive compound 4-aminopyridine (4-AP, 100-200 μM). In control conditions, blue laser photostimulation selectively activated action potential firing in either PV or SOM interneurons and, in both cases, caused a robust GABAA-receptor-mediated inhibition in pyramidal cells (PCs). During perfusion with 4-AP, brief photostimuli (300 ms) activating either PV or SOM interneurons induced patterns of epileptiform activity that closely replicated spontaneously occurring IICs and tonic-clonic ictal discharges. Laser-induced synchronous firing in both interneuronal types elicited large compound GABAergic inhibitory postsynaptic currents (IPSCs) correlating with IICs and preictal spikes. In addition, spontaneous and laser-induced epileptic events were similarly initiated in concurrence with a large increase in extracellular potassium concentration. Finally, interneuron activation was unable to stop or significantly shorten the progression of seizurelike episodes. These results suggest that entorhinal PV and SOM interneurons are nearly equally effective in triggering interictal and ictal discharges that closely resemble human temporal lobe epileptic activity.

  9. Kainate receptors in the rat hippocampus: A distribution and time course of changes in response to unilateral lesions of the entorhinal cortex

    SciTech Connect

    Ulas, J.; Monaghan, D.T.; Cotman, C.W. )

    1990-07-01

    The response of kainate receptors to deafferentation and subsequent reinnervation following unilateral entorhinal cortex lesions was studied in the rat hippocampus using quantitative in vitro autoradiography. The binding levels of (3H)kainic acid (KA) and changes in the distribution of KA sites were investigated in the dentate gyrus molecular layer (ML) and in various terminal zones in the CA1 field at 1, 3, 7, 14, 21, 30, and 60 d postlesion. The data from both the ipsilateral and contralateral hippocampus were compared with those from unoperated controls. The first changes in KA receptor distribution were observed 21 d postlesion when the dense band of KA receptors occupying the inner one-third of the ML expanded into the denervated outer two-thirds of the ipsilateral ML. The spreading of the KA receptor field into previously unoccupied zones continued 30 and 60 d postlesion. At these time points, the zone enriched in (3H)KA binding sites became significantly (on average 50%) wider than in unoperated controls. No changes were observed in either the distribution or binding levels in other hippocampal areas or in the contralateral hippocampus at any studied time point. Saturation analysis of binding in the ipsilateral ML 60 d postlesion revealed changes in the maximum number of receptor sites (Bmax) without changes in KA receptor affinity (Kd). The data suggest that the elevation of the (3H)KA binding in the outer two-thirds of the ML reflects an increase in the number of both low and high affinity receptor binding sites. The pattern of KA receptor redistribution was similar to the well-characterized pattern of sprouting of commissural/associational systems from the inner one-third into the outer two-thirds of the ML after entorhinal lesions.

  10. Optogenetic activation of VGLUT2-expressing excitatory neurons blocks epileptic seizure-like activity in the mouse entorhinal cortex

    PubMed Central

    Yekhlef, Latefa; Breschi, Gian Luca; Taverna, Stefano

    2017-01-01

    We investigated whether an anti-epileptic effect is obtained by selectively activating excitatory neurons expressing ChR2 under the promoter for the synaptic vesicular glutamate transporter 2 (VGLUT2). VGLUT2-expressing cells were optically stimulated while local field potential and whole-cell patch-clamp recordings were performed in mouse entorhinal cortical slices perfused with the proconvulsive compound 4-aminopyridine (4-AP). In control conditions, blue light flashes directly depolarized the majority of putative glutamatergic cells, which in turn synaptically excited GABAergic interneurons. During bath perfusion with 4-AP, photostimuli triggered a fast EPSP-IPSP sequence which was often followed by tonic-clonic seizure-like activity closely resembling spontaneous ictal discharges. The GABAA-receptor antagonist gabazine blocked the progression of both light-induced and spontaneous seizures. Surprisingly, prolonged photostimuli delivered during ongoing seizures caused a robust interruption of synchronous discharges. Such break was correlated with a membrane potential depolarization block in principal cells, while putative GABAergic interneurons changed their firing activity from a burst-like to an irregular single-spike pattern. These data suggest that photostimulation of glutamatergic neurons triggers seizure-like activity only in the presence of an intact GABAergic transmission and that selectively activating the same glutamatergic cells robustly interrupts ongoing seizures by inducing a strong depolarization block, resulting in the disruption of paroxysmal burst-like firing. PMID:28230208

  11. Comparison of imaging biomarkers for Alzheimer's disease: amyloid imaging with [18F]florbetapir positron emission tomography and magnetic resonance imaging voxel-based analysis for entorhinal cortex atrophy.

    PubMed

    Tateno, Amane; Sakayori, Takeshi; Kawashima, Yoshitaka; Higuchi, Makoto; Suhara, Tetsuya; Mizumura, Sunao; Mintun, Mark A; Skovronsky, Daniel M; Honjo, Kazuyoshi; Ishihara, Keiichi; Kumita, Shinichiro; Suzuki, Hidenori; Okubo, Yoshiro

    2015-05-01

    We compared amyloid positron emission tomography (PET) and magnetic resonance imaging (MRI) in subjects clinically diagnosed with Alzheimer's disease (AD), mild cognitive impairment (MCI), and older healthy controls (OHC) in order to test how these imaging biomarkers represent cognitive decline in AD. Fifteen OHC, 19 patients with MCI, and 19 patients with AD were examined by [(18)F]florbetapir PET to quantify the standard uptake value ratio (SUVR) as the degree of amyloid accumulation, by MRI and the voxel-based specific regional analysis system for AD to calculate z-score as the degree of entorhinal cortex atrophy, and by mini-mental state examination (MMSE) and Alzheimer's Disease Assessment Scale-cognitive component--Japanese version (ADAS-Jcog) for cognitive functions. Both cutoff values for measuring AD-like levels of amyloid (1.099 for SUVR) and entorhinal cortex atrophy (1.60 for z-score) were well differentially diagnosed and clinically defined AD from OHC (84.2% for SUVR and 86.7% for z-score). Subgroup analysis based on beta-amyloid positivity revealed that z-score significantly correlated with MMSE (r = -0.626, p < 0.01) and ADAS-Jcog (r = 0.691, p < 0.01) only among subjects with beta-amyloid. This is the first study to compare [(18)F]florbetapir PET and MRI voxel-based analysis of entorhinal cortex atrophy for AD. Both [(18)F]florbetapir PET and MRI detected changes in AD compared with OHC. Considering that entorhinal cortex atrophy correlated well with cognitive decline only among subjects with beta-amyloid, [18F]florbetapir PET makes it possible to detect AD pathology in the early stage, whereas MRI morphometry for subjects with beta-amyloid provides a good biomarker to assess the severity of AD in the later stage. Copyright © 2014 John Wiley & Sons, Ltd.

  12. Short conduction delays cause inhibition rather than excitation to favor synchrony in hybrid neuronal networks of the entorhinal cortex.

    PubMed

    Wang, Shuoguo; Chandrasekaran, Lakshmi; Fernandez, Fernando R; White, John A; Canavier, Carmen C

    2012-01-01

    How stable synchrony in neuronal networks is sustained in the presence of conduction delays is an open question. The Dynamic Clamp was used to measure phase resetting curves (PRCs) for entorhinal cortical cells, and then to construct networks of two such neurons. PRCs were in general Type I (all advances or all delays) or weakly type II with a small region at early phases with the opposite type of resetting. We used previously developed theoretical methods based on PRCs under the assumption of pulsatile coupling to predict the delays that synchronize these hybrid circuits. For excitatory coupling, synchrony was predicted and observed only with no delay and for delays greater than half a network period that cause each neuron to receive an input late in its firing cycle and almost immediately fire an action potential. Synchronization for these long delays was surprisingly tight and robust to the noise and heterogeneity inherent in a biological system. In contrast to excitatory coupling, inhibitory coupling led to antiphase for no delay, very short delays and delays close to a network period, but to near-synchrony for a wide range of relatively short delays. PRC-based methods show that conduction delays can stabilize synchrony in several ways, including neutralizing a discontinuity introduced by strong inhibition, favoring synchrony in the case of noisy bistability, and avoiding an initial destabilizing region of a weakly type II PRC. PRCs can identify optimal conduction delays favoring synchronization at a given frequency, and also predict robustness to noise and heterogeneity. © 2012 Wang et al.

  13. Neonatal functional blockade of the entorhinal cortex results in disruption of accumbal dopaminergic responses observed in latent inhibition paradigm in adult rats.

    PubMed

    Peterschmitt, Y; Meyer, F; Louilot, A

    2007-04-01

    Latent inhibition (LI) has been found to be disrupted in non-treated patients with schizophrenia. Dopaminergic (DAergic) dysfunctioning is generally acknowledged to occur in schizophrenia. Various abnormalities in the entorhinal cortex (ENT) have been described in patients with schizophrenia. Numerous data also suggest that schizophrenia has a neurodevelopmental origin. The present study was designed to test the hypothesis that reversible inactivation of the ENT during neonatal development results in disrupted DA responses characteristic of LI in adult rats. Tetrodotoxin (TTX) was microinjected locally in the left ENT at postnatal day 8 (PND8). DA variations were recorded in the dorsomedial shell and core parts of the nucleus accumbens (Nacc) using in vivo voltammetry in freely-moving grown-up rats in a LI paradigm. In the first session the animals were pre-exposed (PE) to the conditional stimulus (banana odour) alone. In the second they were aversively conditioned to banana odour. In the third (test) session the following results were obtained in PE animals subjected to temporary inactivation of the ENT at PND8: (1) aversive behaviour was observed in TTX-PE conditioned animals; (2) DA variations in the dorsomedial shell and core parts of the Nacc were similar in TTX-PE and non-pre-exposed conditioned rats. These findings strongly suggest that neonatal disconnection of the ENT disrupts LI in adult animals. They may further our understanding of the pathophysiology of schizophrenia.

  14. Brain-derived neurotrophic factor transgenic mice exhibit passive avoidance deficits, increased seizure severity and in vitro hyperexcitability in the hippocampus and entorhinal cortex.

    PubMed

    Croll, S D; Suri, C; Compton, D L; Simmons, M V; Yancopoulos, G D; Lindsay, R M; Wiegand, S J; Rudge, J S; Scharfman, H E

    1999-01-01

    Transgenic mice overexpressing brain-derived neurotrophic factor from the beta-actin promoter were tested for behavioral, gross anatomical and physiological abnormalities. Brain-derived neurotrophic factor messenger RNA overexpression was widespread throughout brain. Overexpression declined with age, such that levels of overexpression decreased sharply by nine months. Brain-derived neurotrophic factor transgenic mice had no gross deformities or behavioral abnormalities. However, they showed a significant passive avoidance deficit. This deficit was dependent on continued overexpression, and resolved with age as brain-derived neurotrophic factor transcripts decreased. In addition, the brain-derived neurotrophic factor transgenic mice showed increased seizure severity in response to kainic acid. Hippocampal slices from brain-derived neurotrophic factor transgenic mice showed hyperexcitability in area CA3 and entorhinal cortex, but not in dentate gyrus. Finally, area CA1 long-term potentiation was disrupted, indicating abnormal plasticity. Our data suggest that overexpression of brain-derived neurotrophic factor in the brain can interfere with normal brain function by causing learning impairments and increased excitability. The results also support the hypothesis that excess brain-derived neurotrophic factor could be pro-convulsant in the limbic system.

  15. Model for Probing Membrane-Cortex Adhesion by Micropipette Aspiration and Fluctuation Spectroscopy

    PubMed Central

    Alert, Ricard; Casademunt, Jaume; Brugués, Jan; Sens, Pierre

    2015-01-01

    We propose a model for membrane-cortex adhesion that couples membrane deformations, hydrodynamics, and kinetics of membrane-cortex ligands. In its simplest form, the model gives explicit predictions for the critical pressure for membrane detachment and for the value of adhesion energy. We show that these quantities exhibit a significant dependence on the active acto-myosin stresses. The model provides a simple framework to access quantitative information on cortical activity by means of micropipette experiments. We also extend the model to incorporate fluctuations and show that detailed information on the stability of membrane-cortex coupling can be obtained by a combination of micropipette aspiration and fluctuation spectroscopy measurements. PMID:25902428

  16. Aspiration.

    PubMed

    Hancocks, S

    2003-03-22

    Aspiration lands in the dictionary between aspidistra and aspirin - a Victorian parlour plant and an anti-inflammatory with new-found cardiac and DVT prevention qualities. What do we make of that as a sign of the times?

  17. G9a/GLP Histone Lysine Dimethyltransferase Complex Activity in the Hippocampus and the Entorhinal Cortex is Required for Gene Activation and Silencing during Memory Consolidation

    PubMed Central

    Gupta-Agarwal, Swati; Franklin, Aimee V.; DeRamus, Thomas; Wheelock, Muriah; Davis, Robin L.; McMahon, Lori L.; Lubin, Farah D.

    2012-01-01

    Learning triggers alterations in gene transcription in brain regions such as the hippocampus and the entorhinal cortex (EC) that are necessary for long-term memory (LTM) formation. Here, we identify an essential role for the G9a/GLP lysine dimethyltransferase complex and the histone H3 lysine 9 di-methylation (H3K9me2) marks it catalyzes, in the transcriptional regulation of genes in area CA1 of the rat hippocampus and the EC during memory consolidation. Contextual fear learning increased global levels of H3K9me2 in area CA1 and the EC, with observable changes at the Zif268, DNMT3a, BDNF exon IV, and cFOS gene promoters, which occurred in concert with mRNA expression. Inhibition of G9a/GLP in the EC, but not in the hippocampus, enhanced contextual fear conditioning relative to control animals. The inhibition of G9a/GLP in the EC induced several histone modifications that include not only methylation but also acetylation. Surprisingly, we found that down-regulation of G9a/GLP activity in the EC enhanced H3K9me2 in area CA1, resulting in transcriptional silencing of the non-memory permissive gene COMT in the hippocampus. In addition, synaptic plasticity studies at two distinct EC-CA1 cellular pathways revealed that G9a/GLP activity is critical for hippocampus-dependent long-term potentiation initiated in the EC via the perforant pathway, but not the temporoammonic pathway. Together, these data demonstrate that G9a/GLP differentially regulates gene transcription in the hippocampus and the EC during memory consolidation. Furthermore, these findings support the possibility of role for G9a/GLP in the regulation of cellular and molecular cross-talk between these two brain regions during LTM formation. PMID:22514307

  18. G9a/GLP histone lysine dimethyltransferase complex activity in the hippocampus and the entorhinal cortex is required for gene activation and silencing during memory consolidation.

    PubMed

    Gupta-Agarwal, Swati; Franklin, Aimee V; Deramus, Thomas; Wheelock, Muriah; Davis, Robin L; McMahon, Lori L; Lubin, Farah D

    2012-04-18

    Learning triggers alterations in gene transcription in brain regions such as the hippocampus and the entorhinal cortex (EC) that are necessary for long-term memory (LTM) formation. Here, we identify an essential role for the G9a/G9a-like protein (GLP) lysine dimethyltransferase complex and the histone H3 lysine 9 dimethylation (H3K9me2) marks it catalyzes, in the transcriptional regulation of genes in area CA1 of the rat hippocampus and the EC during memory consolidation. Contextual fear learning increased global levels of H3K9me2 in area CA1 and the EC, with observable changes at the Zif268, DNMT3a, BDNF exon IV, and cFOS gene promoters, which occurred in concert with mRNA expression. Inhibition of G9a/GLP in the EC, but not in the hippocampus, enhanced contextual fear conditioning relative to control animals. The inhibition of G9a/GLP in the EC induced several histone modifications that include not only methylation but also acetylation. Surprisingly, we found that downregulation of G9a/GLP activity in the EC enhanced H3K9me2 in area CA1, resulting in transcriptional silencing of the non-memory permissive gene COMT in the hippocampus. In addition, synaptic plasticity studies at two distinct EC-CA1 cellular pathways revealed that G9a/GLP activity is critical for hippocampus-dependent long-term potentiation initiated in the EC via the perforant pathway, but not the temporoammonic pathway. Together, these data demonstrate that G9a/GLP differentially regulates gene transcription in the hippocampus and the EC during memory consolidation. Furthermore, these findings support the possibility of a role for G9a/GLP in the regulation of cellular and molecular cross talk between these two brain regions during LTM formation.

  19. The Mechanism of Abrupt Transition between Theta and Hyper-Excitable Spiking Activity in Medial Entorhinal Cortex Layer II Stellate Cells

    PubMed Central

    Kispersky, Tilman; White, John A.; Rotstein, Horacio G.

    2010-01-01

    Recent studies have shown that stellate cells (SCs) of the medial entorhinal cortex become hyper-excitable in animal models of temporal lobe epilepsy. These studies have also demonstrated the existence of recurrent connections among SCs, reduced levels of recurrent inhibition in epileptic networks as compared to control ones, and comparable levels of recurrent excitation among SCs in both network types. In this work, we investigate the biophysical and dynamic mechanism of generation of the fast time scale corresponding to hyper-excitable firing and the transition between theta and fast firing frequency activity in SCs. We show that recurrently connected minimal networks of SCs exhibit abrupt, threshold-like transition between theta and hyper-excitable firing frequencies as the result of small changes in the maximal synaptic (AMPAergic) conductance. The threshold required for this transition is modulated by synaptic inhibition. Similar abrupt transition between firing frequency regimes can be observed in single, self-coupled SCs, which represent a network of recurrently coupled neurons synchronized in phase, but not in synaptically isolated SCs as the result of changes in the levels of the tonic drive. Using dynamical systems tools (phase-space analysis), we explain the dynamic mechanism underlying the genesis of the fast time scale and the abrupt transition between firing frequency regimes, their dependence on the intrinsic SC's currents and synaptic excitation. This abrupt transition is mechanistically different from others observed in similar networks with different cell types. Most notably, there is no bistability involved. ‘In vitro’ experiments using single SCs self-coupled with dynamic clamp show the abrupt transition between firing frequency regimes, and demonstrate that our theoretical predictions are not an artifact of the model. In addition, these experiments show that high-frequency firing is burst-like with a duration modulated by an M-current. PMID

  20. Systemic administration of two different anxiolytic drugs decreases local field potential theta frequency in the medial entorhinal cortex without affecting grid cell firing fields.

    PubMed

    Monaghan, Caitlin K; Chapman, G William; Hasselmo, Michael E

    2017-09-08

    Neurons coding spatial location (grid cells) are found in medial entorhinal cortex (MEC) and demonstrate increasing size of firing fields and spacing between fields (grid scale) along the dorsoventral axis. This change in grid scale correlates with differences in theta frequency, a 6-10Hz rhythm in the local field potential (LFP) and rhythmic firing of cells. A relationship between theta frequency and grid scale can be found when examining grid cells recorded in different locations along the dorsoventral axis of MEC. When describing the relationship between theta frequency and grid scale, it is important to account for the strong positive correlation between theta frequency and running speed. Plotting LFP theta frequency across running speeds dissociates two components of this relationship: slope and intercept of the linear fit. Change in theta frequency through a change in the slope component has been modeled and shown experimentally to affect grid scale, but the prediction that change in the intercept component would not affect grid scale has not been tested experimentally. This prediction about the relationship of intercept to grid scale is the primary hypothesis tested in the experiments presented here. All known anxiolytic drugs decrease hippocampal theta frequency despite their differing mechanisms of action. Specifically, anxiolytics decrease the intercept of the theta frequency-running speed relationship in the hippocampus. Here we demonstrate that anxiolytics decrease the intercept of the theta frequency-running speed relationship in the MEC, similar to hippocampus, and the decrease in frequency through this change in intercept does not affect grid scale. Copyright © 2017. Published by Elsevier Ltd.

  1. 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.

  2. Changes of dendritic spine density and morphology in the superficial layers of the medial entorhinal cortex induced by extremely low-frequency magnetic field exposure.

    PubMed

    Xiong, Jiaxiang; He, Chao; Li, Chao; Tan, Gang; Li, Jingcheng; Yu, Zhengping; Hu, Zhian; Chen, Fang

    2013-01-01

    In the present study, we investigated the effects of chronic exposure (14 and 28 days) to a 0.5 mT 50 Hz extremely low-frequency magnetic field (ELM) on the dendritic spine density and shape in the superficial layers of the medial entorhinal cortex (MEC). We performed Golgi staining to reveal the dendritic spines of the principal neurons in rats. The results showed that ELM exposure induced a decrease in the spine density in the dendrites of stellate neurons and the basal dendrites of pyramidal neurons at both 14 days and 28 days, which was largely due to the loss of the thin and branched spines. The alteration in the density of mushroom and stubby spines post ELM exposure was cell-type specific. For the stellate neurons, ELM exposure slightly increased the density of stubby spines at 28 days, while it did not affect the density of mushroom spines at the same time. In the basal dendrites of pyramidal neurons, we observed a significant decrease in the mushroom spine density only at the later time point post ELM exposure, while the stubby spine density was reduced at 14 days and partially restored at 28 days post ELM exposure. ELM exposure-induced reduction in the spine density in the apical dendrites of pyramidal neurons was only observed at 28 days, reflecting the distinct vulnerability of spines in the apical and basal dendrites. Considering the changes in spine number and shape are involved in synaptic plasticity and the MEC is a part of neural network that is closely related to learning and memory, these findings may be helpful for explaining the ELM exposure-induced impairment in cognitive functions.

  3. Dynamics of rat entorhinal cortex layer II and III cells: characteristics of membrane potential resonance at rest predict oscillation properties near threshold

    PubMed Central

    Erchova, I; Kreck, G; Heinemann, U; Herz, A V M

    2004-01-01

    Neurones generate intrinsic subthreshold membrane potential oscillations (MPOs) under various physiological and behavioural conditions. These oscillations influence neural responses and coding properties on many levels. On the single-cell level, MPOs modulate the temporal precision of action potentials; they also have a pronounced impact on large-scale cortical activity. Recent studies have described a close association between the MPOs of a given neurone and its electrical resonance properties. Using intracellular sharp microelectrode recordings we examine both dynamical characteristics in layers II and III of the entorhinal cortex (EC). Our data from EC layer II stellate cells show strong membrane potential resonances and oscillations, both in the range of 5–15 Hz. At the resonance maximum, the membrane impedance can be more than twice as large as the input resistance. In EC layer III cells, MPOs could not be elicited, and frequency-resolved impedances decay monotonically with increasing frequency or has only a small peak followed by a subsequent decay. To quantify and compare the resonance and oscillation properties, we use a simple mathematical model that includes stochastic components to capture channel noise. Based on this model we demonstrate that electrical resonance is closely related though not equivalent to the occurrence of sag-potentials and MPOs. MPO frequencies can be predicted from the membrane impedance curve for stellate cells. The model also explains the broad-band nature of the observed MPOs. This underscores the importance of intrinsic noise sources for subthreshold phenomena and rules out a deterministic description of MPOs. In addition, our results show that the two identified cell classes in the superficial EC layers, which are known to target different areas in the hippocampus, also have different preferred frequency ranges and dynamic characteristics. Intrinsic cell properties may thus play a major role for the frequency

  4. MicroRNA Expression in the Locus Coeruleus, Entorhinal Cortex, and Hippocampus at Early and Middle Stages of Braak Neurofibrillary Tangle Pathology.

    PubMed

    Llorens, Franc; Thüne, Katrin; Andrés-Benito, Pol; Tahir, Waqas; Ansoleaga, Belén; Hernández-Ortega, Karina; Martí, Eulàlia; Zerr, Inga; Ferrer, Isidro

    2017-09-05

    The present study analyzes by RT-qPCR the expression of microRNA (miRNA)-27a-3p, miRNA-124-3p, miRNA-132-3p, and miRNA-143-3p in the locus coeruleus (LC), entorhinal cortex (EC), CA1 region of the hippocampus (CA1), and dentate gyrus (DG) of middle-aged (MA) individuals with no brain lesions and of cases at Braak and Braak stages I-II and II-IV of neurofibrillary tangle (NFT) pathology. The most affected region is the LC in which miRNA-27a-3p, miRNA-124-3p, and miRNA-143-3p show a trend to increase at stages I-II and are significantly up-regulated at stages III-IV when compared with MA. Only miRNA-143-3p is up-regulated in the EC at stages III-IV when compared with MA and with stages I-II. No modifications in the expression levels of miRNA-27a-3p, miRNA-124-3p, miRNA-132-3p, and miRNA-143-3p are found in CA1 at any stage, whereas miRNA-124-3p is significantly down-regulated in DG at stages I-II. Accompanying in situ hybridization reveals miRNA-27a-3p, miRNA-124-3p, and miRNA-143-3 localization in neurons, indicating that changes in miRNA expression are not a direct effect of changes in the numbers of neurons and glial cells. Present observations show for the first time important miRNA de-regulation in the LC at the first stages of NFT. Since the LC is the main noradrenergic input to the cerebral cortex, key regulator of mood and depression, and one of the first nuclei affected in aging and Alzheimer's disease (AD), these findings provide insights for additional study of the LC in aging and AD.

  5. [Quantitative evaluation of inhibitory effects of epileptic spikes on theta rhythms in the network of hippocampal CA3 and entorhinal cortex in patients with temporal lobe epilepsy].

    PubMed

    Ge, Man-Ling; Guo, Jun-Dan; Chen, Sheng-Hua; Zhang, Ji-Chang; Fu, Xiao-Xuan; Chen, Yu-Min

    2017-02-25

    Epileptic spike is an indicator of hyper-excitability and hyper-synchrony in the neural networks. The inhibitory effects of spikes on theta rhythms (4-8 Hz) might be helpful to understand the mechanism of epileptic damage on the cognitive functions. To quantitatively evaluate the inhibitory effects of spikes on theta rhythms, intracerebral electroencephalogram (EEG) recordings with both sporadic spikes (SSs) and spike-free transient period between adjacent spikes were selected in 4 patients in the status of rapid eyes movement (REM) sleep with temporal lobe epilepsy (TLE) under the pre-surgical monitoring. The electrodes of hippocampal CA3 and entorhinal cortex (EC) were employed, since CA3 and EC built up one of key loops to investigate cognition and epilepsy. These SSs occurred only in CA3, only in EC, or in both CA3 and EC synchronously. Theta power was respectively estimated around SSs and during the spike-free transient period by Gabor wavelet transform and Hilbert transform. The intermittent extent was then estimated to represent for the loss of theta rhythms during the spike-free transient period. The following findings were obtained: (1) The prominent rhythms were in theta frequency band; (2) The spikes could transiently reduce theta power, and the inhibitory effect was severer around SSs in both CA3 and EC synchronously than that around either SSs only in EC or SSs only in CA3; (3) During the spike-free transient period, theta rhythms were interrupted with the intermittent theta rhythms left and theta power level continued dropping, implying the inhibitory effect was sustained. Additionally, the intermittent extent of theta rhythms was converged to the inhibitory extent around SSs; (4) The average theta power level during the spike-free transient period might not be in line with the inhibitory extent of theta rhythms around SSs. It was concluded that the SSs had negative effects on theta rhythms transiently and directly, the inhibitory effects aroused by

  6. Enhanced Actions of Adenosine in Medial Entorhinal Cortex Layer II Stellate Neurons in Temporal Lobe Epilepsy are Mediated via A1 Receptor Activation

    PubMed Central

    Hargus, Nicholas J.; Jennings, Conor; Perez-Reyes, Edward; Bertram, Edward H.; Patel, Manoj K.

    2011-01-01

    Summary Purpose The adenosinergic system is known to exert an inhibitory affect in the brain and as such adenosine has been considered an endogenous anticonvulsant. Entorhinal cortex (EC) layer II neurons, which serve as the primary input to the hippocampus, are spared in temporal lobe epilepsy (TLE) and become hyperexcitable. Since these neurons also express adenosine receptors, the activity of these neurons may be controlled by adenosine, specifically during seizure activity when adenosine levels are thought to rise. In light of this, we determined if the actions of adenosine on medial EC (mEC) layer II stellate neurons are augmented in TLE and by which receptor subtype. Methods Horizontal brain slices were prepared from rats exhibiting spontaneous seizures (TLE) induced by electrical stimulation and compared with age matched control rats. mEC layer II stellate neurons were visually identified and action potentials (AP) evoked by either a series of depolarizing current injection steps or via presynaptic stimulation of mEC deep layers. The effects of adenosine were compared with actions of adenosine A1 and A2A receptor-specific agonists (CPA and CGS 21680) and antagonists (DPCPX and ZM241385) respectively. Immunohistochemical and qPCR techniques were also employed to assess relative adenosine A1 receptor message and expression. Key Findings mEC layer II stellate neurons were hyper-excitable in TLE, evoking a higher frequency of AP's when depolarized and generating bursts of AP's when synaptically stimulated. Adenosine reduced AP frequency and synaptically evoked AP's in a dose dependent manner (500 nM – 100 μM); however, in TLE, the inhibitory actions of adenosine occurred at concentrations that were without affect in control neurons. In both cases, the inhibitory actions of adenosine were mediated via activation of the A1 and not the A2A receptor subtype. qPCR and immunohistochemical experiments revealed an up-regulation of the adenosine A1 mRNA and an

  7. Gonadal status-dependent effects of in vivo β-estradiol administration to female rats on in vitro epileptiform activity induced by low [Mg2+]₀ in combined hippocampus-entorhinal cortex slices.

    PubMed

    Velíšková, Jana; Velíšek, Libor

    2013-12-01

    There are controversial data regarding estrogen effects on neuronal excitability. We investigated whether β-estradiol (EB) administration to ovariectomized (OVX) or gonadally intact female rats alters epileptiform activity within the dentate gyrus network induced in vitro by removing [Mg2+]o in combined hippocampus-entorhinal cortex slices. In vivo EB administration significantly influenced the epileptiform activity in gonadal status-dependent manner. The onset of epileptiform discharges was modestly delayed in slices from OVX rats replaced with physiologically relevant doses of EB but the number of discharges was not affected. In contrast, EB administration to gonadally intact rats had robust effects such that: EB delayed the onset of discharges but significantly increased their number within the dentate gyrus network. Our data suggest that EB in physiologically relevant concentrations does not seem to negatively affect hippocampal neuronal excitability, nevertheless supraphysiological EB levels may enhance seizure severity.

  8. Dopaminergic modulation of GABAergic transmission in the entorhinal cortex: concerted roles of α1 adrenoreceptors, inward rectifier K⁺, and T-type Ca²⁺ channels.

    PubMed

    Cilz, Nicholas I; Kurada, Lalitha; Hu, Binqi; Lei, Saobo

    2014-12-01

    Whereas the entorhinal cortex (EC) receives profuse dopaminergic innervations from the midbrain, the effects of dopamine (DA) on γ-Aminobutyric acid (GABA)ergic interneurons in this brain region have not been determined. We probed the actions of DA on GABAA receptor-mediated synaptic transmission in the EC. Application of DA increased the frequency, not the amplitude, of spontaneous IPSCs (sIPSCs) and miniature IPSCs (mIPSCs) recorded from entorhinal principal neurons, but slightly reduced the amplitude of the evoked IPSCs. The effects of DA were unexpectedly found to be mediated by α1 adrenoreceptors, but not by DA receptors. DA endogenously released by the application of amphetamine also increased the frequency of sIPSCs. Ca(2+) influx via T-type Ca(2+) channels was required for DA-induced facilitation of sIPSCs and mIPSCs. DA depolarized and enhanced the firing frequency of action potentials of interneurons. DA-induced depolarization was independent of extracellular Na(+) and Ca(2+) and did not require the functions of hyperpolarization-activated (Ih) channels and T-type Ca(2+) channels. DA-generated currents showed a reversal potential close to the K(+) reversal potential and inward rectification, suggesting that DA inhibits the inward rectifier K(+) channels (Kirs). Our results demonstrate that DA facilitates GABA release by activating α1 adrenoreceptors to inhibit Kirs, which further depolarize interneurons resulting in secondary Ca(2+) influx via T-type Ca(+) channels. © The Author 2013. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  9. Optogenetic dissection of entorhinal-hippocampal functional connectivity.

    PubMed

    Zhang, Sheng-Jia; Ye, Jing; Miao, Chenglin; Tsao, Albert; Cerniauskas, Ignas; Ledergerber, Debora; Moser, May-Britt; Moser, Edvard I

    2013-04-05

    We used a combined optogenetic-electrophysiological strategy to determine the functional identity of entorhinal cells with output to the place-cell population in the hippocampus. Channelrhodopsin-2 (ChR2) was expressed selectively in the hippocampus-targeting subset of entorhinal projection neurons by infusing retrogradely transportable ChR2-coding recombinant adeno-associated virus in the hippocampus. Virally transduced ChR2-expressing cells were identified in medial entorhinal cortex as cells that fired at fixed minimal latencies in response to local flashes of light. A large number of responsive cells were grid cells, but short-latency firing was also induced in border cells and head-direction cells, as well as cells with irregular or nonspatial firing correlates, which suggests that place fields may be generated by convergence of signals from a broad spectrum of entorhinal functional cell types.

  10. Spontaneous rhythmic field potentials of isolated mouse hippocampal-subicular-entorhinal cortices in vitro.

    PubMed

    Wu, C P; Huang, H L; Asl, M Nassiri; He, J W; Gillis, J; Skinner, F K; Zhang, L

    2006-10-15

    The rodent hippocampal circuit is capable of exhibiting in vitro spontaneous rhythmic field potentials (SRFPs) of 1-4 Hz that originate from the CA3 area and spread to the CA1 area. These SRFPs are largely correlated with GABA-A IPSPs in pyramidal neurons and repetitive discharges in inhibitory interneurons. As such, their generation is thought to result from cooperative network activities involving both pyramidal neurons and GABAergic interneurons. Considering that the hippocampus, subiculum and entorhinal cortex function as an integrated system crucial for memory and cognition, it is of interest to know whether similar SRFPs occur in hippocampal output structures (that is, the subiculum and entorhinal cortex), and if so, to understand the cellular basis of these subicular and entorhinal SRFPs as well as their temporal relation to hippocampal SRFPs. We explored these issues in the present study using thick hippocampal-subicular-entorhinal cortical slices prepared from adult mice. SRFPs were found to spread from the CA1 area to the subicular and entorhinal cortical areas. Subicular and entorhinal cortical SRFPs were correlated with mixed IPSPs/EPSPs in local pyramidal neurons, and their generation was dependent upon the activities of GABA-A and AMPA glutamate receptors. In addition, the isolated subicular circuit could elicit SRFPs independent of CA3 inputs. We hypothesize that the SRFPs represent a basal oscillatory activity of the hippocampal-subicular-entorhinal cortices and that the subiculum functions as both a relay and an amplifier, spreading the SRFPs from the hippocampus to the entorhinal cortex.

  11. Entorhinal-Hippocampal Neuronal Circuits Bridge Temporally Discontiguous Events

    ERIC Educational Resources Information Center

    Kitamura, Takashi; Macdonald, Christopher J.; Tonegawa, Susumu

    2015-01-01

    The entorhinal cortex (EC)-hippocampal (HPC) network plays an essential role for episodic memory, which preserves spatial and temporal information about the occurrence of past events. Although there has been significant progress toward understanding the neural circuits underlying the spatial dimension of episodic memory, the relevant circuits…

  12. Entorhinal-Hippocampal Neuronal Circuits Bridge Temporally Discontiguous Events

    ERIC Educational Resources Information Center

    Kitamura, Takashi; Macdonald, Christopher J.; Tonegawa, Susumu

    2015-01-01

    The entorhinal cortex (EC)-hippocampal (HPC) network plays an essential role for episodic memory, which preserves spatial and temporal information about the occurrence of past events. Although there has been significant progress toward understanding the neural circuits underlying the spatial dimension of episodic memory, the relevant circuits…

  13. Protective effect of APOE epsilon 2 on intrinsic functional connectivity of the entorhinal cortex is associated with better episodic memory in elderly individuals with risk factors for Alzheimer's disease

    PubMed Central

    Chen, Jiu; Shu, Hao; Wang, Zan; Liu, Duan; Shi, Yongmei; Xu, Lin; Zhang, Zhijun

    2016-01-01

    The apolipoprotein E (APOE) ε4 allele associates with accelerating the conversion from amnestic mild cognitive impairment (aMCI) to Alzheimer's disease (AD), whereas the protectiveAPOEε2 allele appears to be against the disease. Moreover, entorhinal cortex (ERC) is one of the earliest brain regions of AD pathology that disrupts the formation of episodic memory. To investigate the effects of APOE ε2 and ε4alleles on functional connectivity (FC) of ERC and cognition in aMCI. Methods The FC analyses of ERC were performed in 83 aMCI (9 ε2-carrier, 44 ε3ε3, and 30 ε4-carrier) and 88 healthy controls (HC, 15 ε2-carrier, 40 ε3ε3, and 33 ε4-carrier). Multiple linear regression model was performed between the altered ERC connectivities and cognition. In the ERC network, aMCI with ε4-carriers showed decreased FC in the bilateral middle temporal gyrus (MTG), right precuneus, and right precentral gyrus (PreCG), while ε2-carriers showed increased FC in these regions (except the right PreCG) compared to HC. The altered FC between ERC and right MTG correlated with episodic memory performance in aMCI carried ε2 and ε4 alleles. These results suggest that the effects ofAPOEon the ERC network are closely linked to the role of this gene on AD risk, which aMCI with ε4-carriers can accelerate the pathological progression of network-based mechanisms while ε2-carriers may play a protective role in contributing to a compensatory mechanism. It further suggests that APOE can appear to directly affect the ERC-MTG neural pathway associated with the impairment of episodic memory in aMCI. PMID:27542235

  14. Entorhinal cortical innervation of parvalbumin-containing neurons (Basket and Chandelier cells) in the rat Ammon's horn.

    PubMed

    Kiss, J; Buzsaki, G; Morrow, J S; Glantz, S B; Leranth, C

    1996-01-01

    Physiological data suggest that in the CA1-CA3 hippocampal areas of rats, entorhinal cortical efferents directly influence the activity of interneurons, in addition to pyramidal cells. To verify this hypothesis, the following experiments were performed: 1) light microscopic double-immunostaining for parvalbumin and the anterograde tracer Phaseolus vulgaris-leucoagglutinin injected into the entorhinal cortex; 2) light and electron microscopic analysis of cleaved spectrin-immunostained (i.e., degenerating axons and boutons) hippocampal sections following entorhinal cortex lesion; and 3) an electron microscopic study of parvalbumin-immunostained hippocampal sections after entorhinal cortex lesion. The results demonstrate that in the stratum lacunosum-moleculare of the CA1 and CA3 regions, entorhinal cortical axons form asymmetric synaptic contacts on parvalbumin-containing dendritic shafts. In the stratum lacunosum-moleculare, parvalbumin-immunoreactive dendrites represent processes of GABAergic, inhibitory basket and chandelier cells; these interneurons innervate the perisomatic area and axon initial segments of pyramidal cells, respectively. A feed-forward activation of these neurons by the entorhinal input may explain the strong, short-latency inhibition of pyramidal cells.

  15. Entorhinal volume, aerobic fitness, and recognition memory in healthy young adults: A voxel-based morphometry study.

    PubMed

    Whiteman, Andrew S; Young, Daniel E; Budson, Andrew E; Stern, Chantal E; Schon, Karin

    2016-02-01

    Converging evidence supports the hypothesis effects of aerobic exercise and environmental enrichment are beneficial for cognition, in particular for hippocampus-supported learning and memory. Recent work in humans suggests that exercise training induces changes in hippocampal volume, but it is not known if aerobic exercise and fitness also impact the entorhinal cortex. In animal models, aerobic exercise increases expression of growth factors, including brain derived neurotrophic factor (BDNF). This exercise-enhanced expression of growth hormones may boost synaptic plasticity, and neuronal survival and differentiation, potentially supporting function and structure in brain areas including but not limited to the hippocampus. Here, using voxel based morphometry and a standard graded treadmill test to determine cardio-respiratory fitness (Bruce protocol; ·VO2 max), we examined if entorhinal and hippocampal volumes were associated with cardio-respiratory fitness in healthy young adults (N=33). In addition, we examined if volumes were modulated by recognition memory performance and by serum BDNF, a putative marker of synaptic plasticity. Our results show a positive association between volume in right entorhinal cortex and cardio-respiratory fitness. In addition, average gray matter volume in the entorhinal cortex, bilaterally, was positively associated with memory performance. These data extend prior work on the cerebral effects of aerobic exercise and fitness to the entorhinal cortex in healthy young adults thus providing compelling evidence for a relationship between aerobic fitness and structure of the medial temporal lobe memory system.

  16. Entorhinal volume, aerobic fitness, and recognition memory in healthy young adults: a voxel-based morphometry study1

    PubMed Central

    Whiteman, Andrew S.; Young, Daniel E.; Budson, Andrew E.; Stern, Chantal E.; Schon, Karin

    2015-01-01

    Converging evidence supports the hypothesis effects of aerobic exercise and environmental enrichment are beneficial for cognition, in particular for hippocampus-supported learning and memory. Recent work in humans suggests exercise training induces changes in hippocampal volume, but it is not known if aerobic exercise and fitness also impact the entorhinal cortex. In animal models, aerobic exercise increases expression of growth factors, including brain derived neurotrophic factor (BDNF). This exercise-enhanced expression of growth hormones may boost synaptic plasticity, and neuronal survival and differentiation, potentially supporting function and structure in brain areas including but not limited to the hippocampus. Here, using voxel based morphometry and a standard graded treadmill test to determine cardio-respiratory fitness (Bruce protocol; VO2 max), we examined if entorhinal and hippocampal volumes were associated with cardio-respiratory fitness in healthy young adults (N = 33). In addition, we examined if volumes were modulated by recognition memory performance and by serum BDNF, a putative marker of synaptic plasticity. Our results show a positive association between volume in right entorhinal cortex and cardio-respiratory fitness. In addition, average gray matter volume in the entorhinal cortex, bilaterally, was positively associated with memory performance. These data extend prior work on the cerebral effects of aerobic exercise and fitness to the entorhinal cortex in healthy young adults thus providing compelling evidence for a relationship between aerobic fitness and structure of the medial temporal lobe memory system. PMID:26631814

  17. Head direction is coded more strongly than movement direction in a population of entorhinal neurons.

    PubMed

    Raudies, Florian; Brandon, Mark P; Chapman, G William; Hasselmo, Michael E

    2015-09-24

    The spatial firing pattern of entorhinal grid cells may be important for navigation. Many different computational models of grid cell firing use path integration based on movement direction and the associated movement speed to drive grid cells. However, the response of neurons to movement direction has rarely been tested, in contrast to multiple studies showing responses of neurons to head direction. Here, we analyzed the difference between head direction and movement direction during rat movement and analyzed cells recorded from entorhinal cortex for their tuning to movement direction. During foraging behavior, movement direction differs significantly from head direction. The analysis of neuron responses shows that only 5 out of 758 medial entorhinal cells show significant coding for both movement direction and head direction when evaluating periods of rat behavior with speeds above 10 cm/s and ±30° angular difference between movement and head direction. None of the cells coded movement direction alone. In contrast, 21 cells in this population coded only head direction during behavioral epochs with these constraints, indicating much stronger coding of head direction in this population. This suggests that the movement direction signal required by most grid cell models may arise from other brain structures than the medial entorhinal cortex. This article is part of a Special Issue entitled SI: Brain and Memory.

  18. Robust path integration in the entorhinal grid cell system with hippocampal feed-back.

    PubMed

    Samu, Dávid; Eros, Péter; Ujfalussy, Balázs; Kiss, Tamás

    2009-07-01

    Animals are able to update their knowledge about their current position solely by integrating the speed and the direction of their movement, which is known as path integration. Recent discoveries suggest that grid cells in the medial entorhinal cortex might perform some of the essential underlying computations of path integration. However, a major concern over path integration is that as the measurement of speed and direction is inaccurate, the representation of the position will become increasingly unreliable. In this paper, we study how allothetic inputs can be used to continually correct the accumulating error in the path integrator system. We set up the model of a mobile agent equipped with the entorhinal representation of idiothetic (grid cell) and allothetic (visual cells) information and simulated its place learning in a virtual environment. Due to competitive learning, a robust hippocampal place code emerges rapidly in the model. At the same time, the hippocampo-entorhinal feed-back connections are modified via Hebbian learning in order to allow hippocampal place cells to influence the attractor dynamics in the entorhinal cortex. We show that the continuous feed-back from the integrated hippocampal place representation is able to stabilize the grid cell code.

  19. Head direction is coded more strongly than movement direction in a population of entorhinal neurons

    PubMed Central

    Raudies, Florian; Brandon, Mark P.; Chapman, G. William; Hasselmo, Michael E.

    2014-01-01

    The spatial firing pattern of entorhinal grid cells may be important for navigation. Many different computational models of grid cell firing use path integration based on movement direction and the associated movement speed to drive grid cells. However, the response of neurons to movement direction has rarely been tested, in contrast to multiple studies showing responses of neurons to head direction. Here, we analyzed the difference between head direction and movement direction during rat movement and analyzed cells recorded from entorhinal cortex for their tuning to movement direction. During foraging behavior, movement direction differs significantly from head direction. The analysis of neuron responses shows that only 5 out of 758 medial entorhinal cells show significant coding for both movement direction and head direction when evaluating periods of rat behavior with speeds above 10 cm/sec and ±30° angular difference between movement and head direction. None of the cells coded movement direction alone. In contrast, 21 cells in this population coded only head direction during behavioral epochs with these constraints, indicating much stronger coding of head direction in this population. This suggests that the movement direction signal required by most grid cell models may arise from other brain structures than the medial entorhinal cortex. PMID:25451111

  20. APOE associated hemispheric asymmetry of entorhinal cortical thickness in aging and Alzheimer’s disease

    PubMed Central

    Donix, Markus; Burggren, Alison C.; Scharf, Maria; Marschner, Kira; Suthana, Nanthia A.; Siddarth, Prabha; Krupa, Allison K.; Jones, Michael; Martin-Harris, Laurel; Ercoli, Linda M.; Miller, Karen J.; Werner, Annett; von Kummer, Rüdiger; Sauer, Cathrin; Small, Gary W.; Holthoff, Vjera A.; Bookheimer, Susan Y.

    2013-01-01

    Across species structural and functional hemispheric asymmetry is a fundamental feature of the brain. Environmental and genetic factors determine this asymmetry during brain development and modulate its interaction with brain disorders. The e4 allele of the apolipoprotein E gene (APOE-4) is a risk factor for Alzheimer’s disease, associated with regionally specific effects on brain morphology and function during the life span. Furthermore, entorhinal and hippocampal hemispheric asymmetry could be modified by pathology during Alzheimer’s disease development. Using high-resolution magnetic resonance imaging and a cortical unfolding technique we investigated whether carrying the APOE-4 allele influences hemispheric asymmetry in the entorhinal cortex and the hippocampus among patients with Alzheimer’s disease as well as in middle-aged and older cognitively healthy individuals. APOE-4 carriers showed a thinner entorhinal cortex in the left hemisphere when compared with the right hemisphere across all participants. Non-carriers of the allele showed this asymmetry only in the patient group. Cortical thickness in the hippocampus did not vary between hemispheres among APOE-4 allele carriers and non-carriers. The APOE-4 allele modulates hemispheric asymmetry in entorhinal cortical thickness. Among Alzheimer’s disease patients, this asymmetry might be less dependent on the APOE genotype and a more general marker of incipient disease pathology. PMID:24080518

  1. Aspiration pneumonia

    MedlinePlus

    Anaerobic pneumonia; Aspiration of vomitus; Necrotizing pneumonia; Aspiration pneumonitis ... The type of bacteria that caused the pneumonia depends on: Your ... facility, for example) Whether you were recently hospitalized ...

  2. Amount of lifetime video gaming is positively associated with entorhinal, hippocampal and occipital volume.

    PubMed

    Kühn, S; Gallinat, J

    2014-07-01

    Playing video games is a popular leisure activity among children and adults, and may therefore potentially influence brain structure. We have previously shown a positive association between probability of gray matter (GM) volume in the ventral striatum and frequent video gaming in adolescence. Here we set out to investigate structural correlates of video gaming in adulthood, as the effects observed in adolescents may reflect only a fraction of the potential neural long-term effects seen in adults. On magnetic resonance imaging (MRI) scans of 62 male adults, we computed voxel-based morphometry to explore the correlation of GM with the lifetime amount of video gaming (termed joystick years). We found a significant positive association between GM in bilateral parahippocamal region (entorhinal cortex) and left occipital cortex/inferior parietal lobe and joystick years (P<0.001, corrected for multiple comparisons). An exploratory analysis showed that the entorhinal GM volume can be predicted by the video game genres played, such as logic/puzzle games and platform games contributing positively, and action-based role-playing games contributing negatively. Furthermore, joystick years were positively correlated with hippocampus volume. The association of lifetime amount of video game playing with bilateral entorhinal cortex, hippocampal and occipital GM volume could reflect adaptive neural plasticity related to navigation and visual attention.

  3. Bone marrow aspiration

    MedlinePlus

    Iliac crest tap; Sternal tap; Leukemia - bone marrow aspiration; Aplastic anemia - bone marrow aspiration; Myelodysplastic syndrome - bone marrow aspiration; Thrombocytopenia - bone marrow aspiration; Myelofibrosis - bone marrow aspiration

  4. Entorhinal Cortical Ocean Cells Encode Specific Contexts and Drive Context-Specific Fear Memory.

    PubMed

    Kitamura, Takashi; Sun, Chen; Martin, Jared; Kitch, Lacey J; Schnitzer, Mark J; Tonegawa, Susumu

    2015-09-23

    Forming distinct representations and memories of multiple contexts and episodes is thought to be a crucial function of the hippocampal-entorhinal cortical network. The hippocampal dentate gyrus (DG) and CA3 are known to contribute to these functions, but the role of the entorhinal cortex (EC) is poorly understood. Here, we show that Ocean cells, excitatory stellate neurons in the medial EC layer II projecting into DG and CA3, rapidly form a distinct representation of a novel context and drive context-specific activation of downstream CA3 cells as well as context-specific fear memory. In contrast, Island cells, excitatory pyramidal neurons in the medial EC layer II projecting into CA1, are indifferent to context-specific encoding or memory. On the other hand, Ocean cells are dispensable for temporal association learning, for which Island cells are crucial. Together, the two excitatory medial EC layer II inputs to the hippocampus have complementary roles in episodic memory.

  5. How does the modular organization of entorhinal grid cells develop?

    PubMed Central

    Pilly, Praveen K.; Grossberg, Stephen

    2014-01-01

    The entorhinal-hippocampal system plays a crucial role in spatial cognition and navigation. Since the discovery of grid cells in layer II of medial entorhinal cortex (MEC), several types of models have been proposed to explain their development and operation; namely, continuous attractor network models, oscillatory interference models, and self-organizing map (SOM) models. Recent experiments revealing the in vivo intracellular signatures of grid cells (Domnisoru et al., 2013; Schmidt-Heiber and Hausser, 2013), the primarily inhibitory recurrent connectivity of grid cells (Couey et al., 2013; Pastoll et al., 2013), and the topographic organization of grid cells within anatomically overlapping modules of multiple spatial scales along the dorsoventral axis of MEC (Stensola et al., 2012) provide strong constraints and challenges to existing grid cell models. This article provides a computational explanation for how MEC cells can emerge through learning with grid cell properties in modular structures. Within this SOM model, grid cells with different rates of temporal integration learn modular properties with different spatial scales. Model grid cells learn in response to inputs from multiple scales of directionally-selective stripe cells (Krupic et al., 2012; Mhatre et al., 2012) that perform path integration of the linear velocities that are experienced during navigation. Slower rates of grid cell temporal integration support learned associations with stripe cells of larger scales. The explanatory and predictive capabilities of the three types of grid cell models are comparatively analyzed in light of recent data to illustrate how the SOM model overcomes problems that other types of models have not yet handled. PMID:24917799

  6. How does the modular organization of entorhinal grid cells develop?

    PubMed

    Pilly, Praveen K; Grossberg, Stephen

    2014-01-01

    The entorhinal-hippocampal system plays a crucial role in spatial cognition and navigation. Since the discovery of grid cells in layer II of medial entorhinal cortex (MEC), several types of models have been proposed to explain their development and operation; namely, continuous attractor network models, oscillatory interference models, and self-organizing map (SOM) models. Recent experiments revealing the in vivo intracellular signatures of grid cells (Domnisoru et al., 2013; Schmidt-Heiber and Hausser, 2013), the primarily inhibitory recurrent connectivity of grid cells (Couey et al., 2013; Pastoll et al., 2013), and the topographic organization of grid cells within anatomically overlapping modules of multiple spatial scales along the dorsoventral axis of MEC (Stensola et al., 2012) provide strong constraints and challenges to existing grid cell models. This article provides a computational explanation for how MEC cells can emerge through learning with grid cell properties in modular structures. Within this SOM model, grid cells with different rates of temporal integration learn modular properties with different spatial scales. Model grid cells learn in response to inputs from multiple scales of directionally-selective stripe cells (Krupic et al., 2012; Mhatre et al., 2012) that perform path integration of the linear velocities that are experienced during navigation. Slower rates of grid cell temporal integration support learned associations with stripe cells of larger scales. The explanatory and predictive capabilities of the three types of grid cell models are comparatively analyzed in light of recent data to illustrate how the SOM model overcomes problems that other types of models have not yet handled.

  7. Hyperexcitability in combined entorhinal/hippocampal slices of adult rat after exposure to brain-derived neurotrophic factor.

    PubMed

    Scharfman, H E

    1997-08-01

    Effects of brain-derived neurotrophic factor (BDNF) in area CA3, the dentate gyrus, and medial entorhinal cortex were examined electrophysiologically by bath application of BDNF in slices containing the hippocampus and entorhinal cortex. Bath application of 25-100 ng/ml BDNF for 30-90 min increased responses to single afferent stimuli in selective pathways in the majority of slices. In area CA3, responses to mossy fiber stimulation increased in 73% of slices and entorhinal cortex responses to white matter stimulation increased in 64% of slices. After exposure to BDNF, these areas also demonstrated evidence of hyperexcitability, because responses to repetitive stimulation (1-Hz paired pulses for several s) produced multiple population spikes in response to mossy fiber stimulation in CA3 or multiple field potentials in response to white matter stimulation in the entorhinal cortex. Repetitive field potentials persisted after repetitive stimulation ended and usually were followed by spreading depression. Enhancement of responses to single stimuli and hyperexcitability were never evoked in untreated slices or after bath application of boiled BDNF or cytochrome C. The tyrosine kinase antagonist K252a (2 microM) blocked the effects of BDNF. In area CA3, both the potentiation of responses to single stimuli and hyperexcitability showed afferent specificity, because responses to mossy fiber stimulation were affected but responses to fimbria or Schaffer collateral stimulation were not. In addition, regional specificity was demonstrated in that the dentate gyrus was much less affected. The effects of BDNF in area CA3 were similar to those produced by bath application of low doses of kainic acid, which is thought to modulate glutamate release from mossy fiber terminals by a presynaptic action. These results suggest that BDNF has acute effects on excitability in different areas of the hippocampal-entorhinal circuit. These effects appear to be greatest in areas that are highly

  8. Crossed pathways from the entorhinal area to the fascia dentata. II. Provokable in rats.

    PubMed

    Zimmer, J; Hjorth-Simonsen, A

    1975-05-01

    In the rat thhe perforant pathways from the entorhinal area normally innervate the fascia dentata only ipsilaterally. However, unilateral ablation of the entorhinal area (deentorhination) induces the formation of an anomalous crossed projection from the intact contralateral entorhinal area to the septal portion of the deafferented fascia dentata. After deentorhination of rats aged 1-30 days the organization of this projection was analyzed (a) by producing secondary lesions in the intact entorhinal area of perforant paths and observing the results anterograde degeneration with Fink-Heimer silver impregnation techniques, and (b) by staining with Timm's sulfide silver method whichmakes the terminal fields of afferent systems stand out in different tones of colors. Both methods showed the crossed entorhino-dentate projection to consist of two separable components. They were named the crossed medial perforant path and the crossed lateral perforant path, corresponding to their similarity in origin, dendritic localization of termination and Timm stainability to the ordinary, uncrossed medial and the lateral perforant pathways (MPP and LPP) which arise in the medial and lateral parts of the entorhinal cortex, respectively. Similarly induced crossed projections were demonstrated to the subcallosal continuation of fascia dentata, the fasciola cinerea. The heaviest terminal field of the crossed entorhino-dentate projection which was found in the most rostral and medial parts of the deafferented fascia dentata correlated with a lack of expected aberrant extension into theMPP and LPP terminal zones of commissural and ipsilateral hippocampodentate fibers. In Fink-Heimer preparations there was little variation in the distribution of the aberrant crossed sustems over the range of ages studied although the chronic operations performed earliest postnatally (5 days) tended to produce the heaviest representation. This latter observation appeared consistent with changes in the Timm

  9. "Aspiration disease".

    PubMed

    Pradhan, D J; Ikins, P M

    1976-03-01

    Aspiration disease, a term used to define both an acute and chronic form of a disease entity, is described. Etiological factors, pathophysiology and therapy are discussed with emphasis on aspiration of gastric juice. A brief mention of a small clinical experience is included.

  10. Entorhinal Principal Neurons Mediate Brain-stimulation Treatments for Epilepsy.

    PubMed

    Xu, Zhenghao; Wang, Yi; Chen, Bin; Xu, Cenglin; Wu, Xiaohua; Wang, Ying; Zhang, Shihong; Hu, Weiwei; Wang, Shuang; Guo, Yi; Zhang, Xiangnan; Luo, Jianhong; Duan, Shumin; Chen, Zhong

    2016-12-01

    Brain stimulation is an alternative treatment for epilepsy. However, the neuronal circuits underlying its mechanisms remain obscure. We found that optogenetic activation (1Hz) of entorhinal calcium/calmodulin-dependent protein kinase II α (CaMKIIα)-positive neurons, but not GABAergic neurons, retarded hippocampal epileptogenesis and reduced hippocampal seizure severity, similar to that of entorhinal low-frequency electrical stimulation (LFES). Optogenetic inhibition of entorhinal CaMKIIα-positive neurons blocked the antiepileptic effect of LFES. The channelrhodopsin-2-eYFP labeled entorhinal CaMKIIα-positive neurons primarily targeted the hippocampus, and the activation of these fibers reduced hippocampal seizure severity. By combining extracellular recording and pharmacological methods, we found that activating entorhinal CaMKIIα-positive neurons induced the GABA-mediated inhibition of hippocampal neurons. Optogenetic activation of focal hippocampal GABAergic neurons mimicked this neuronal modulatory effect and reduced hippocampal seizure severity, but the anti-epileptic effect is weaker than that of entorhinal LFES, which may be due to the limited spatial neuronal modulatory effect of focal photo-stimulation. Our results demonstrate a glutamatergic-GABAergic neuronal circuit for LFES treatment of epilepsy, which is mediated by entorhinal principal neurons.

  11. A circuit-level model of hippocampal place field dynamics modulated by entorhinal grid and suppression-generating cells.

    PubMed

    Jayet Bray, Laurence C; Quoy, Mathias; Harris, Frederick C; Goodman, Philip H

    2010-01-01

    Hippocampal "place cells" and the precession of their extracellularly recorded spiking during traversal of a "place field" are well-established phenomena. More recent experiments describe associated entorhinal "grid cell" firing, but to date only conceptual models have been offered to explain the potential interactions among entorhinal cortex (EC) and hippocampus. To better understand not only spatial navigation, but mechanisms of episodic and semantic memory consolidation and reconsolidation, more detailed physiological models are needed to guide confirmatory experiments. Here, we report the results of a putative entorhinal-hippocampal circuit level model that incorporates recurrent asynchronous-irregular non-linear (RAIN) dynamics, in the context of recent in vivo findings showing specific intracellular-extracellular precession disparities and place field destabilization by entorhinal lesioning. In particular, during computer-simulated rodent maze navigation, our model demonstrate asymmetric ramp-like depolarization, increased theta power, and frequency (that can explain the phase precession disparity), and a role for STDP and K(AHP) channels. Additionally, we propose distinct roles for two entorhinal cell populations projecting to hippocampus. Grid cell populations transiently trigger place field activity, while tonic "suppression-generating cell" populations minimize aberrant place cell activation, and limit the number of active place cells during traversal of a given field. Applied to place-cell RAIN networks, this tonic suppression explains an otherwise seemingly discordant association with overall increased firing. The findings of this circuit level model suggest in vivo and in vitro experiments that could refute or support the proposed mechanisms of place cell dynamics and modulating influences of EC.

  12. A Kalman filtering approach to the representation of kinematic quantities by the hippocampal-entorhinal complex.

    PubMed

    Osborn, Graham Wordsworth

    2010-12-01

    Several regions of the brain which represent kinematic quantities are grouped under a single state-estimator framework. A theoretic effort is made to predict the activity of each cell population as a function of time using a simple state estimator (the Kalman filter). Three brain regions are considered in detail: the parietal cortex (reaching cells), the hippocampus (place cells and head-direction cells), and the entorhinal cortex (grid cells). For the reaching cell and place cell examples, we compute the perceived probability distributions of objects in the environment as a function of the observations. For the grid cell example, we show that the elastic behavior of the grids observed in experiments arises naturally from the Kalman filter. To our knowledge, the application of a tensor Kalman filter to grid cells is completely novel.

  13. Linear Look-Ahead in Conjunctive Cells: An Entorhinal Mechanism for Vector-Based Navigation

    PubMed Central

    Kubie, John L.; Fenton, André A.

    2012-01-01

    The crisp organization of the “firing bumps” of entorhinal grid cells and conjunctive cells leads to the notion that the entorhinal cortex may compute linear navigation routes. Specifically, we propose a process, termed “linear look-ahead,” by which a stationary animal could compute a series of locations in the direction it is facing. We speculate that this computation could be achieved through learned patterns of connection strengths among entorhinal neurons. This paper has three sections. First, we describe the minimal grid cell properties that will be built into our network. Specifically, the network relies on “rigid modules” of neurons, where all members have identical grid scale and orientation, but differ in spatial phase. Additionally, these neurons must be densely interconnected with synapses that are modifiable early in the animal’s life. Second, we investigate whether plasticity during short bouts of locomotion could induce patterns of connections amongst grid cells or conjunctive cells. Finally, we run a simulation to test whether the learned connection patterns can exhibit linear look-ahead. Our results are straightforward. A simulated 30-min walk produces weak strengthening of synapses between grid cells that do not support linear look-ahead. Similar training in a conjunctive cell module produces a small subset of very strong connections between cells. These strong pairs have three properties: the pre- and post-synaptic cells have similar heading direction. The cell pairs have neighboring grid bumps. Finally, the spatial offset of firing bumps of the cell pair is in the direction of the common heading preference. Such a module can produce strong and accurate linear look-ahead starting in any location and extending in any direction. We speculate that this process may: (1) compute linear paths to goals; (2) update grid cell firing during navigation; and (3) stabilize the rigid modules of grid cells and conjunctive cells. PMID:22557948

  14. Entorhinal Cortical Ocean Cells Encode Specific Contexts and Drive Context-Specific Fear Memory

    PubMed Central

    Kitamura, Takashi; Sun, Chen; Martin, Jared; Kitch, Lacey J; Schnitzer, Mark J; Tonegawa, Susumu

    2016-01-01

    Summary Forming distinct representations and memories of multiple contexts and episodes is thought to be a crucial function of the hippocampal-entorhinal cortical network. The hippocampal dentate gyrus (DG) and CA3 are known to contribute to these functions but the role of the entorhinal cortex (EC) is poorly understood. Here, we show that Ocean cells, excitatory stellate neurons in the medial EC layer II projecting into DG and CA3, rapidly form a distinct representation of a novel context and drive context-specific activation of downstream CA3 cells as well as context-specific fear memory. In contrast, Island cells, excitatory pyramidal neurons in the medial EC layer II projecting into CA1, are indifferent to context-specific encoding or memory. On the other hand, Ocean cells are dispensable for temporal association learning, for which Island cells are crucial. Together, the two excitatory medial EC layer II inputs to the hippocampus have complementary roles in episodic memory. PMID:26402611

  15. APOE-Sensitive Cholinergic Sprouting Compensates for Hippocampal Dysfunctions Due to Reduced Entorhinal Input.

    PubMed

    Bott, Jean-Bastien; Héraud, Céline; Cosquer, Brigitte; Herbeaux, Karine; Aubert, Julien; Sartori, Maxime; Goutagny, Romain; Mathis, Chantal

    2016-10-05

    Brain mechanisms compensating for cerebral lesions may mitigate the progression of chronic neurodegenerative disorders such as Alzheimer's disease (AD). Mild cognitive impairment (MCI), which often precedes AD, is characterized by neuronal loss in the entorhinal cortex (EC). This loss leads to a hippocampal disconnection syndrome that drives clinical progression. The concomitant sprouting of cholinergic terminals in the hippocampus has been proposed to compensate for reduced EC glutamatergic input. However, in absence of direct experimental evidence, the compensatory nature of the cholinergic sprouting and its putative mechanisms remain elusive. Transgenic mice expressing the human APOE4 allele, the main genetic risk factor for sporadic MCI/AD, display impaired cholinergic sprouting after EC lesion. Using these mice as a tool to manipulate cholinergic sprouting in a disease-relevant way, we showed that this sprouting was necessary and sufficient for the acute compensation of EC lesion-induced spatial memory deficit before a slower glutamatergic reinnervation took place. We also found that partial EC lesion generates abnormal hyperactivity in EC/dentate networks. Dentate hyperactivity was abolished by optogenetic stimulation of cholinergic fibers. Therefore, control of dentate hyperactivity by cholinergic sprouting may be involved in functional compensation after entorhinal lesion. Our results also suggest that dentate hyperactivity in MCI patients may be directly related to EC neuronal loss. Impaired sprouting during the MCI stage may contribute to the faster cognitive decline reported in APOE4 carriers. Beyond the amyloid contribution, the potential role of both cholinergic sprouting and dentate hyperactivity in AD symptomatogenesis should be considered in designing new therapeutic approaches. Currently, curative treatment trials for Alzheimer's disease (AD) have failed. The endogenous ability of the brain to cope with neuronal loss probably represents one of the

  16. Distinct speed dependence of entorhinal island and ocean cells, including respective grid cells

    PubMed Central

    Sun, Chen; Kitamura, Takashi; Yamamoto, Jun; Martin, Jared; Pignatelli, Michele; Kitch, Lacey J.; Schnitzer, Mark J.; Tonegawa, Susumu

    2015-01-01

    Entorhinal–hippocampal circuits in the mammalian brain are crucial for an animal’s spatial and episodic experience, but the neural basis for different spatial computations remain unknown. Medial entorhinal cortex layer II contains pyramidal island and stellate ocean cells. Here, we performed cell type-specific Ca2+ imaging in freely exploring mice using cellular markers and a miniature head-mounted fluorescence microscope. We found that both oceans and islands contain grid cells in similar proportions, but island cell activity, including activity in a proportion of grid cells, is significantly more speed modulated than ocean cell activity. We speculate that this differential property reflects island cells’ and ocean cells’ contribution to different downstream functions: island cells may contribute more to spatial path integration, whereas ocean cells may facilitate contextual representation in downstream circuits. PMID:26170279

  17. OLM interneurons differentially modulate CA3 and entorhinal inputs to hippocampal CA1 neurons

    PubMed Central

    Leão, Richardson N; Mikulovic, Sanja; Leão, Katarina E; Munguba, Hermany; Gezelius, Henrik; Enjin, Anders; Patra, Kalicharan; Eriksson, Anders; Loew, Leslie M.; Tort, Adriano BL; Kullander, Klas

    2012-01-01

    The vast diversity of GABAergic interneurons is believed to endow hippocampal microcircuits with the required flexibility for memory encoding and retrieval. However, dissection of the functional roles of defined interneuron types have been hampered by the lack of cell specific tools. Here we report a precise molecular marker for a population of hippocampal GABAergic interneurons known as oriens lacunosum-moleculare (OLM) cells. By combining novel transgenic mice and optogenetic tools, we demonstrate that OLM cells have a key role in gating the information flow in CA1, facilitating the transmission of intrahippocampal information (from CA3) while reducing the influence of extrahippocampal inputs (from the entorhinal cortex). We further demonstrate that OLM cells are interconnected by gap junctions, receive direct cholinergic inputs from subcortical afferents, and account for the effect of nicotine on synaptic plasticity of the Schaffer collateral pathway. Our results suggest that acetylcholine acting through OLM cells can control the mnemonic processes executed by the hippocampus. PMID:23042082

  18. OLM interneurons differentially modulate CA3 and entorhinal inputs to hippocampal CA1 neurons.

    PubMed

    Leão, Richardson N; Mikulovic, Sanja; Leão, Katarina E; Munguba, Hermany; Gezelius, Henrik; Enjin, Anders; Patra, Kalicharan; Eriksson, Anders; Loew, Leslie M; Tort, Adriano B L; Kullander, Klas

    2012-11-01

    The vast diversity of GABAergic interneurons is believed to endow hippocampal microcircuits with the required flexibility for memory encoding and retrieval. However, dissection of the functional roles of defined interneuron types has been hampered by the lack of cell-specific tools. We identified a precise molecular marker for a population of hippocampal GABAergic interneurons known as oriens lacunosum-moleculare (OLM) cells. By combining transgenic mice and optogenetic tools, we found that OLM cells are important for gating the information flow in CA1, facilitating the transmission of intrahippocampal information (from CA3) while reducing the influence of extrahippocampal inputs (from the entorhinal cortex). Furthermore, we found that OLM cells were interconnected by gap junctions, received direct cholinergic inputs from subcortical afferents and accounted for the effect of nicotine on synaptic plasticity of the Schaffer collateral pathway. Our results suggest that acetylcholine acting through OLM cells can control the mnemonic processes executed by the hippocampus.

  19. Channel noise is essential for perithreshold oscillations in entorhinal stellate neurons.

    PubMed

    Dorval, Alan D; White, John A

    2005-10-26

    Previous experimental and computational work (for review, see White et al., 2000) has suggested that channel noise, generated by the stochastic flicker of voltage-gated ion channels, can be a major contributor to electrical membrane noise in neurons. In spiny stellate neurons of the entorhinal cortex, we remove the primary source of channel noise by pharmacologically blocking the native persistent Na+ conductance. Via the dynamic-clamp technique (Robinson and Kawai, 1993; Sharp et al., 1993), we then introduce virtual persistent Na+ channels into the membranes of the stellate neurons. By altering the mathematical properties of these virtual "knock-ins," we demonstrate that stochastic flicker of persistent Na+ channels is necessary for the existence of slow perithreshold oscillations that characterize stellate neurons. Channel noise also alters the ability of stellate neurons to phase lock to weak sinusoidal stimuli. These results provide the first direct demonstration that physiological levels of channel noise can produce qualitative changes in the integrative properties of neurons.

  20. Relationships between hippocampal sharp waves, ripples and fast gamma oscillation: influence of dentate and entorhinal cortical activity

    PubMed Central

    Sullivan, David; Csicsvari, Jozsef; Mizuseki, Kenji; Montgomery, Sean; Diba, Kamran; Buzsáki, György

    2011-01-01

    Summary Hippocampal sharp waves (SPW) and associated fast (‘ripple’) oscillations in the CA1 region are among the most synchronous physiological patterns in the mammalian brain. Using two-dimensional arrays of electrodes for recording local field potentials and unit discharges in freely moving rats, we studied the emergence of ripple oscillations (140–220 Hz) and compared their origin and cellular-synaptic mechanisms with fast gamma oscillations (90–140 Hz). We show that (a) hippocampal SPW-Rs and fast gamma oscillations are quantitatively distinct patterns but involve the same networks and share similar mechanisms, (b) both the frequency and magnitude of fast oscillations is positively correlated with the magnitude of SPWs, (c) during both ripples and fast gamma oscillations the frequency of network oscillation is higher in CA1 than in CA3, (d) SPWs and associated firing of neurons are synchronous in the dorsal hippocampus and dorso-medial entorhinal cortex but ripples are confined to the CA1 pyramidal layer and its downstream targets and (e) the emergence of CA3 population bursts, a prerequisite for SPW-ripples, is biased by activity patterns in the dentate gyrus and entorhinal cortex, with highest probability of ripples associated with an ‘optimum’ level of dentate gamma power. We hypothesize that each hippocampal subnetwork possesses distinct resonant properties, tuned by the magnitude of the excitatory drive. PMID:21653864

  1. Transsynaptic progression of amyloid-β-induced neuronal dysfunction within the entorhinal-hippocampal network

    PubMed Central

    Harris, Julie A.; Devidze, Nino; Verret, Laure; Ho, Kaitlyn; Halabisky, Brian; Thwin, Myo T.; Kim, Daniel; Hamto, Patricia; Lo, Iris; Yu, Gui-Qiu; Palop, Jorge J.; Masliah, Eliezer; Mucke, Lennart

    2011-01-01

    SUMMARY The entorhinal cortex (EC) is one of the earliest affected and most vulnerable brain regions in Alzheimer’s disease (AD), which is associated with amyloid-β (Aβ) accumulation in many brain areas. We show selective overexpression of mutant amyloid precursor protein (APP) predominantly in layer II/III neurons of the EC causes cognitive and behavioral abnormalities characteristic of mouse models with widespread neuronal APP overexpression, including hyperactivity, disinhibition, and spatial learning and memory deficits. Overexpression of APP/Aβ in the EC elicited abnormalities in synaptic functions and activity-related molecules in the dentate gyrus and CA1, as well as epileptiform activity in parietal cortex. Soluble Aβ was observed in the dentate gyrus and Aβ deposits in the hippocampus were localized to perforant pathway terminal fields. Thus, APP/Aβ expression in EC neurons can cause transsynaptic deficits, which could initiate the cortical-hippocampal network dysfunction observed in mouse models and human patients with AD. PMID:21040845

  2. Entorhinal tau pathology disrupts hippocampal-prefrontal oscillatory coupling during associative learning.

    PubMed

    Tanninen, Stephanie E; Nouriziabari, Bardia; Morrissey, Mark D; Bakir, Rami; Dayton, Robert D; Klein, Ronald L; Takehara-Nishiuchi, Kaori

    2017-10-01

    A neural signature of asymptomatic preclinical Alzheimer's disease (AD) is disrupted connectivity between brain regions; however, its underlying mechanisms remain unknown. Here, we tested whether a preclinical pathologic feature, tau aggregation in the entorhinal cortex (EC) is sufficient to disrupt the coordination of local field potentials (LFPs) between its efferent regions. P301L-mutant human tau or green fluorescent protein (GFP) was virally overexpressed in the EC of adult rats. LFPs were recorded from the dorsal hippocampus and prelimbic medial prefrontal cortex while the rats underwent trace eyeblink conditioning where they learned to associate 2 stimuli separated by a short time interval. In GFP-expressing rats, the 2 regions strengthened phase-phase and amplitude-amplitude couplings of theta and gamma oscillations during the interval separating the paired stimuli. Despite normal memory acquisition, this learning-related, inter-region oscillatory coupling was attenuated in the tau-expressing rats while prefrontal phase-amplitude theta-gamma cross-frequency coupling was elevated. Thus, EC tau aggregation caused aberrant long-range circuit activity during associative learning, identifying a culprit for the neural signature of preclinical AD stages. Copyright © 2017 Elsevier Inc. All rights reserved.

  3. Joint Aspiration (Arthrocentesis)

    MedlinePlus

    ... Old Feeding Your 1- to 2-Year-Old Joint Aspiration (Arthrocentesis) KidsHealth > For Parents > Joint Aspiration (Arthrocentesis) Print A A A What's in ... español Aspiración articular (artrocentesis) What It Is A joint aspiration (arthrocentesis) is a test that involves withdrawing ( ...

  4. Gateways of ventral and dorsal streams in mouse visual cortex

    PubMed Central

    Wang, Quanxin; Gao, Enquan; Burkhalter, Andreas

    2011-01-01

    It is widely held that the spatial processing functions underlying rodent navigation are similar to those encoding human episodic memory (Doeller et al, 2010). Spatial and nonspatial information are provided by all senses including vision. It has been suggested that visual inputs are fed to the navigational network in cortex and hippocampus through dorsal and ventral intracortical streams (Whitlock et al, 2008), but this has not been shown directly in rodents. We have used cyto- and chemoarchitectonic markers, topographic mapping of receptive fields and pathway tracing to determine in mouse visual cortex whether the lateromedial (LM) and the anterolateral fields (AL), which are the principal targets of primary visual cortex (V1) (Wang and Burkhalter, 2007) specialized for processing nonspatial and spatial visual information (Gao et al, 2006), are distinct areas with diverse connections. We have found that the LM/AL border coincides with a change in type 2 muscarinic acetylcholine receptor (m2AChR) expression in layer 4 and with the representation of the lower visual field periphery. Our quantitative analyses further show that LM strongly projects to temporal cortex as well as the lateral entorhinal cortex, which has weak spatial selectivity (Hargreaves et al, 2005). In contrast, AL has stronger connections with posterior parietal cortex, motor cortex and the spatially selective medial entorhinal cortex (Haftig et al, 2005). These results support the notion that LM and AL are architecturally, topographically and connectionally distinct areas of extrastriate visual cortex and that they are gateways for ventral and dorsal streams. PMID:21289200

  5. Role of the hippocampal-entorhinal loop in temporal lobe epilepsy: extra- and intracellular study in the isolated guinea pig brain in vitro.

    PubMed

    Paré, D; deCurtis, M; Llinás, R

    1992-05-01

    This article introduces a new experimental paradigm for the study of temporal lobe epilepsy. This approach utilizes the isolated guinea pig brain in vitro preparation, which generates a pattern of hypersynchronous neuronal activity similar to the peculiar 8-30 Hz rhythm characterizing stereoelectroencephalographic hippocampal recordings in human temporal lobe epilepsy. The present report describes an attempt to identify the functional events underlying the epileptiform activities observed in this preparation. Rhythmic epileptiform discharges (EDs), here defined as population spikes (PSs) recorded from somata or dendritic layers, were induced in the hippocampal formation of the isolated guinea pig brain maintained in vitro by tetanic stimulation of the entorhinal cortex (EC). Two patterns of EDs were distinguished by performing simultaneous field potential recordings along the dentate gyrus (DG), EC, CA1, and CA3. During stage 1, the first self-sustained EDs were isolated PSs occurring at a frequency of 2-3 Hz at all levels of the entorhinal-hippocampal loop, the only exception being the DG, where no signs of synchronized neuronal discharge could be found. Over the next 30-50 sec, the temporal organization of these EDs changed dramatically. During stage 2, at all levels of the entorhinal-hippocampal loop, EDs occurred in 0.3-0.5 sec trains of 16-25 Hz population spikes interrupted by 0.7-1.3 sec silent periods. The transition between stages 1 and 2 coincided with the occurrence of population spikes in the DG. Laminar analyses and multiple simultaneous field potential recordings revealed that the trains of EDs observed in stage 2 resulted from the repetitive, sequential activation of the hippocampal-entorhinal loop. In the transverse axis, the earliest event usually occurred in the CA3 region. Thereafter, population spikes occurred sequentially in the CA1 region, EC, DG, and back to the CA3 region. Intracellular recordings confirmed that the EDs recorded

  6. An efficient coding theory for a dynamic trajectory predicts non-uniform allocation of entorhinal grid cells to modules.

    PubMed

    Mosheiff, Noga; Agmon, Haggai; Moriel, Avraham; Burak, Yoram

    2017-06-01

    Grid cells in the entorhinal cortex encode the position of an animal in its environment with spatially periodic tuning curves with different periodicities. Recent experiments established that these cells are functionally organized in discrete modules with uniform grid spacing. Here we develop a theory for efficient coding of position, which takes into account the temporal statistics of the animal's motion. The theory predicts a sharp decrease of module population sizes with grid spacing, in agreement with the trend seen in the experimental data. We identify a simple scheme for readout of the grid cell code by neural circuitry, that can match in accuracy the optimal Bayesian decoder. This readout scheme requires persistence over different timescales, depending on the grid cell module. Thus, we propose that the brain may employ an efficient representation of position which takes advantage of the spatiotemporal statistics of the encoded variable, in similarity to the principles that govern early sensory processing.

  7. Disruption of amygdala-entorhinal-hippocampal network in late-life depression.

    PubMed

    Leal, Stephanie L; Noche, Jessica A; Murray, Elizabeth A; Yassa, Michael A

    2017-04-01

    Episodic memory deficits are evident in late-life depression (LLD) and are associated with subtle synaptic and neurochemical changes in the medial temporal lobes (MTL). However, the particular mechanisms by which memory impairment occurs in LLD are currently unknown. We tested older adults with (DS+) and without (DS-) depressive symptoms using high-resolution fMRI that is capable of discerning signals in hippocampal subfields and amygdala nuclei. Scanning was conducted during performance of an emotional discrimination task used previously to examine the relationship between depressive symptoms and amygdala-mediated emotional modulation of hippocampal pattern separation in young adults. We found that hippocampal dentate gyrus (DG)/CA3 activity was reduced during correct discrimination of negative stimuli and increased during correct discrimination of neutral items in DS+ compared to DS- adults. The extent of the latter increase was correlated with symptom severity. Furthermore, DG/CA3 and basolateral amygdala (BLA) activity predicted discrimination performance on negative trials, a relationship that depended on symptom severity. The impact of the BLA on depressive symptom severity was mediated by the DG/CA3 during discrimination of neutral items, and by the lateral entorhinal cortex (LEC) during false recognition of positive items. These results shed light on a novel mechanistic account for amygdala-hippocampal network changes and concurrent alterations in emotional episodic memory in LLD. The BLA-LEC-DG/CA3 network, which comprises a key pathway by which emotion modulates memory, is specifically implicated in LLD. © 2017 Wiley Periodicals, Inc.

  8. Seizure-induced plasticity of h channels in entorhinal cortical layer III pyramidal neurons.

    PubMed

    Shah, Mala M; Anderson, Anne E; Leung, Victor; Lin, Xiaodi; Johnston, Daniel

    2004-10-28

    The entorhinal cortex (EC) provides the predominant excitatory drive to the hippocampal CA1 and subicular neurons in chronic epilepsy. Discerning the mechanisms underlying signal integration within EC neurons is essential for understanding network excitability alterations involving the hippocampus during epilepsy. Twenty-four hours following a single seizure episode when there were no behavioral or electrographic seizures, we found enhanced spontaneous activity still present in the rat EC in vivo and in vitro. The increased excitability was accompanied by a profound reduction in I(h) in EC layer III neurons and a significant decline in HCN1 and HCN2 subunits that encode for h channels. Consequently, dendritic excitability was enhanced, resulting in increased neuronal firing despite hyperpolarized membrane potentials. The loss of I(h) and the increased neuronal excitability persisted for 1 week following seizures. Our results suggest that dendritic I(h) plays an important role in determining the excitability of EC layer III neurons and their associated neural networks.

  9. Acute Intraoperative Pulmonary Aspiration.

    PubMed

    Nason, Katie S

    2015-08-01

    Acute intraoperative aspiration is a potentially fatal complication with significant associated morbidity. Patients undergoing thoracic surgery are at increased risk for anesthesia-related aspiration, largely due to the predisposing conditions associated with this complication. Awareness of the risk factors, predisposing conditions, maneuvers to decrease risk, and immediate management options by the thoracic surgeon and the anesthesia team is imperative to reducing risk and optimizing patient outcomes associated with acute intraoperative pulmonary aspiration. Based on the root-cause analyses that many of the aspiration events can be traced back to provider factors, having an experienced anesthesiologist present for high-risk cases is also critical.

  10. How Entorhinal Grid Cells May Learn Multiple Spatial Scales from a Dorsoventral Gradient of Cell Response Rates in a Self-organizing Map

    PubMed Central

    Grossberg, Stephen; Pilly, Praveen K.

    2012-01-01

    Place cells in the hippocampus of higher mammals are critical for spatial navigation. Recent modeling clarifies how this may be achieved by how grid cells in the medial entorhinal cortex (MEC) input to place cells. Grid cells exhibit hexagonal grid firing patterns across space in multiple spatial scales along the MEC dorsoventral axis. Signals from grid cells of multiple scales combine adaptively to activate place cells that represent much larger spaces than grid cells. But how do grid cells learn to fire at multiple positions that form a hexagonal grid, and with spatial scales that increase along the dorsoventral axis? In vitro recordings of medial entorhinal layer II stellate cells have revealed subthreshold membrane potential oscillations (MPOs) whose temporal periods, and time constants of excitatory postsynaptic potentials (EPSPs), both increase along this axis. Slower (faster) subthreshold MPOs and slower (faster) EPSPs correlate with larger (smaller) grid spacings and field widths. A self-organizing map neural model explains how the anatomical gradient of grid spatial scales can be learned by cells that respond more slowly along the gradient to their inputs from stripe cells of multiple scales, which perform linear velocity path integration. The model cells also exhibit MPO frequencies that covary with their response rates. The gradient in intrinsic rhythmicity is thus not compelling evidence for oscillatory interference as a mechanism of grid cell firing. A response rate gradient combined with input stripe cells that have normalized receptive fields can reproduce all known spatial and temporal properties of grid cells along the MEC dorsoventral axis. This spatial gradient mechanism is homologous to a gradient mechanism for temporal learning in the lateral entorhinal cortex and its hippocampal projections. Spatial and temporal representations may hereby arise from homologous mechanisms, thereby embodying a mechanistic “neural relativity” that may clarify

  11. Overactivation of NR2B-containing NMDA receptors through entorhinal-hippocampal connection initiates accumulation of hyperphosphorylated tau in rat hippocampus after transient middle cerebral artery occlusion.

    PubMed

    Xu, Cheng-Shi; Liu, An-Chun; Chen, Juan; Pan, Zhi-Yong; Wan, Qi; Li, Zhi-Qiang; Wang, Ze-Fen

    2015-08-01

    Middle cerebral artery occlusion (MCAO) induces secondary damages in the hippocampus that is remote from primary ischemic regions. Tau hyperphosphorylation is an important risk for neurodegenerative diseases. Increased tau phosphorylation has been identified in ischemic cortex, but little is known regarding the changes in the hippocampus. We showed that unilateral transient MCAO induced accumulation of hyperphosphorylated tau and concurrent dephosphorylation of glycogen synthase kinase-3β at Ser 9 in the ipsilateral hippocampus. These MCAO-induced changes were not reproduced when glutamatergic inputs from the entorhinal cortex to the hippocampus were transected; however, the changes were mimicked by intrahippocampal N-methyl-d-aspartate (NMDA) administration. Inhibition of NMDA receptor (NMDAR) subunit NR2B, but not NR2A activity in the hippocampus attenuated the accumulation of hyperphosphorylated tau and spatial cognitive impairment in MCAO rats. Together, our data suggest that overactivation of NR2B-containing NMDARs through entorhinal-hippocampal connection plays an important role in the accumulation of hyperphosphorylated tau in the hippocampus following MCAO. Glycogen synthase kinase-3β is an important protein kinase involved in NMDARs-mediated tau hyperphosphorylation. This study indicates that early inhibition of NR2B-containing NMDARs may represent a potential strategy to prevent or delay the occurrence of post-stroke dementia. Middle cerebral artery occlusion induces secondary damage in the hippocampus that is remote from primary ischemic regions. We propose that excessive activation of NR2B-containing NMDA receptors through entorhinal-hippocampal connection initiated the accumulation of hyperphosphorylated tau in the hippocampus, which subsequently induced cognitive deficit. This study provides new insights into the prospects of NR2B inhibition in stoke therapy.

  12. Aspiration in Jaffna Tamil

    ERIC Educational Resources Information Center

    Thananjayarajasingham, S.

    1975-01-01

    The article accounts for the phenomenon of aspiration in Jaffna Tamil, a dialect distinct form South Indian dialects of Tamil. Not being distinctive orphonologically determined, aspiration is dealt with as a prosodic feature affecting voiceless stops in various positions. Distribution and symbolic representation are handled; kymographic evidence…

  13. Aspirations of Rural Youth.

    ERIC Educational Resources Information Center

    Bajema, Duane H.; Miller, W. Wade; Williams, David L.

    2002-01-01

    Of 883 Iowa high school seniors, 60% lived in towns, 40% on farms. Both groups had a high level of congruence between educational and occupational aspirations and perceived minimal barriers to goal achievement. Farm and town students had equally diverse aspirations. (Contains 23 references.) (SK)

  14. Dorsal-ventral organization of theta-like activity intrinsic to entorhinal stellate neurons is mediated by differences in stochastic current fluctuations.

    PubMed

    Dodson, Paul D; Pastoll, Hugh; Nolan, Matthew F

    2011-06-15

    The membrane potential dynamics of stellate neurons in layer II of the medial entorhinal cortex are important for neural encoding of location. Previous studies suggest that these neurons generate intrinsic theta-frequency membrane potential oscillations, with a period that depends on neuronal location on the dorsal–ventral axis of themedial entorhinal cortex, and which in behaving animals could support generation of grid-like spatial firing fields. To address the nature and organization of this theta-like activity, we adopt the Lombmethod of least-squares spectral analysis. We demonstrate that peaks in frequency spectra that differ significantly from Gaussian noise do not necessarily imply the existence of a periodic oscillator, but can instead arise from filtered stochastic noise or a stochastic random walk. We show that theta-like membrane potential activity recorded fromstellate neurons in mature brain slices is consistentwith stochastic mechanisms, but not with generation by a periodic oscillator. The dorsal–ventral organization of intrinsic theta-likemembrane potential activity, and themodification of this activity during block of HCN channels, both reflect altered frequency distributions of stochastic spectral peaks, rather than tuning of a periodic oscillator. Our results demonstrate the importance of distinguishing periodic oscillations from stochastic processes.We suggest that dorsal–ventral tuning of theta-like membrane potential activity is due to differences in stochastic current fluctuations resulting from organization of ion channels that also control synaptic integration.

  15. Dorsal–ventral organization of theta-like activity intrinsic to entorhinal stellate neurons is mediated by differences in stochastic current fluctuations

    PubMed Central

    Dodson, Paul D; Pastoll, Hugh; Nolan, Matthew F

    2011-01-01

    Abstract The membrane potential dynamics of stellate neurons in layer II of the medial entorhinal cortex are important for neural encoding of location. Previous studies suggest that these neurons generate intrinsic theta-frequency membrane potential oscillations, with a period that depends on neuronal location on the dorsal–ventral axis of the medial entorhinal cortex, and which in behaving animals could support generation of grid-like spatial firing fields. To address the nature and organization of this theta-like activity, we adopt the Lomb method of least-squares spectral analysis. We demonstrate that peaks in frequency spectra that differ significantly from Gaussian noise do not necessarily imply the existence of a periodic oscillator, but can instead arise from filtered stochastic noise or a stochastic random walk. We show that theta-like membrane potential activity recorded from stellate neurons in mature brain slices is consistent with stochastic mechanisms, but not with generation by a periodic oscillator. The dorsal–ventral organization of intrinsic theta-like membrane potential activity, and the modification of this activity during block of HCN channels, both reflect altered frequency distributions of stochastic spectral peaks, rather than tuning of a periodic oscillator. Our results demonstrate the importance of distinguishing periodic oscillations from stochastic processes. We suggest that dorsal–ventral tuning of theta-like membrane potential activity is due to differences in stochastic current fluctuations resulting from organization of ion channels that also control synaptic integration. PMID:21502290

  16. Medial perirhinal cortex disambiguates confusable objects.

    PubMed

    Kivisaari, Sasa L; Tyler, Lorraine K; Monsch, Andreas U; Taylor, Kirsten I

    2012-12-01

    Our brain disambiguates the objects in our cluttered visual world seemingly effortlessly, enabling us to understand their significance and to act appropriately. The role of anteromedial temporal structures in this process, particularly the perirhinal cortex, is highly controversial. In some accounts, the perirhinal cortex is necessary for differentiating between perceptually and semantically confusable objects. Other models claim that the perirhinal cortex neither disambiguates perceptually confusable objects nor plays a unique role in semantic processing. One major hurdle to resolving this central debate is the fact that brain damage in human patients typically encompasses large portions of the anteromedial temporal lobe, such that the identification of individual substructures and precise neuroanatomical locus of the functional impairments has been difficult. We tested these competing accounts in patients with Alzheimer's disease with varying degrees of atrophy in anteromedial structures, including the perirhinal cortex. To assess the functional contribution of each anteromedial temporal region separately, we used a detailed region of interest approach. From each participant, we obtained magnetic resonance imaging scans and behavioural data from a picture naming task that contrasted naming performance with living and non-living things as a way of manipulating perceptual and semantic confusability; living things are more similar to one another than non-living things, which have more distinctive features. We manually traced neuroanatomical regions of interest on native-space cortical surface reconstructions to obtain mean thickness estimates for the lateral and medial perirhinal cortex and entorhinal cortex. Mean cortical thickness in each region of interest, and hippocampal volume, were submitted to regression analyses predicting naming performance. Importantly, atrophy of the medial perirhinal cortex, but not lateral perirhinal cortex, entorhinal cortex or

  17. Joint Aspiration (Arthrocentesis)

    MedlinePlus

    ... arthritis, or JRA), systemic lupus erythematosus (SLE), and Lyme disease. Joint aspiration is diagnostic but it also can ... Parents MORE ON THIS TOPIC Evaluate Your Child's Lyme Disease Risk Living With Lupus Bones, Muscles, and Joints ...

  18. Bone marrow aspiration (image)

    MedlinePlus

    ... amount of bone marrow is removed during a bone marrow aspiration. The procedure is uncomfortable, but can be tolerated by both children and adults. The marrow can be studied to determine ... metabolic products are stored in certain bone marrow cells.

  19. Movement Dependence and Layer Specificity of Entorhinal Phase Precession in Two-Dimensional Environments

    PubMed Central

    Reifenstein, Eric; Stemmler, Martin; Herz, Andreas V. M.; Kempter, Richard; Schreiber, Susanne

    2014-01-01

    As a rat moves, grid cells in its entorhinal cortex (EC) discharge at multiple locations of the external world, and the firing fields of each grid cell span a hexagonal lattice. For movements on linear tracks, spikes tend to occur at successively earlier phases of the theta-band filtered local field potential during the traversal of a firing field – a phenomenon termed phase precession. The complex movement patterns observed in two-dimensional (2D) open-field environments may fundamentally alter phase precession. To study this question at the behaviorally relevant single-run level, we analyzed EC spike patterns as a function of the distance traveled by the rat along each trajectory. This analysis revealed that cells across all EC layers fire spikes that phase-precess; indeed, the rate and extent of phase precession were the same, only the correlation between spike phase and path length was weaker in EC layer III. Both slope and correlation of phase precession were surprisingly similar on linear tracks and in 2D open-field environments despite strong differences in the movement statistics, including running speed. While the phase-precession slope did not correlate with the average running speed, it did depend on specific properties of the animal's path. The longer a curving path through a grid-field in a 2D environment, the shallower was the rate of phase precession, while runs that grazed a grid field tangentially led to a steeper phase-precession slope than runs through the field center. Oscillatory interference models for grid cells do not reproduce the observed phenomena. PMID:24959748

  20. Layer III neurons control synchronized waves in the immature cerebral cortex.

    PubMed

    Namiki, Shigehiro; Norimoto, Hiroaki; Kobayashi, Chiaki; Nakatani, Kei; Matsuki, Norio; Ikegaya, Yuji

    2013-01-16

    Correlated spiking activity prevails in immature cortical networks and is believed to contribute to neuronal circuit maturation; however, its spatiotemporal organization is not fully understood. Using wide-field calcium imaging from acute whole-brain slices of rat pups on postnatal days 1-6, we found that correlated spikes were initiated in the anterior part of the lateral entorhinal cortex and propagated anteriorly to the frontal cortex and posteriorly to the medial entorhinal cortex, forming traveling waves that engaged almost the entire cortex. The waves were blocked by ionotropic glutamatergic receptor antagonists but not by GABAergic receptor antagonists. During wave events, glutamatergic and GABAergic synaptic inputs were balanced and induced UP state-like depolarization. Magnified monitoring with cellular resolution revealed that the layer III neurons were first activated when the waves were initiated. Consistent with this finding, layer III contained a larger number of neurons that were autonomously active, even under a blockade of synaptic transmission. During wave propagation, the layer III neurons constituted a leading front of the wave. The waves did not enter the parasubiculum; however, in some cases, they were reflected at the parasubicular border and propagated back in the opposite direction. During this reflection process, the layer III neurons in the medial entorhinal cortex maintained persistent activity. Thus, our data emphasize the role of layer III in early network behaviors and provide insight into the circuit mechanisms through which cerebral cortical networks maturate.

  1. Dopaminergic enhancement of excitatory synaptic transmission in layer II entorhinal neurons is dependent on D₁-like receptor-mediated signaling.

    PubMed

    Glovaci, I; Caruana, D A; Chapman, C A

    2014-01-31

    The modulatory neurotransmitter dopamine induces concentration-dependent changes in synaptic transmission in the entorhinal cortex, in which high concentrations of dopamine suppress evoked excitatory postsynaptic potentials (EPSPs) and lower concentrations induce an acute synaptic facilitation. Whole-cell current-clamp recordings were used to investigate the dopaminergic facilitation of synaptic responses in layer II neurons of the rat lateral entorhinal cortex. A constant bath application of 1 μM dopamine resulted in a consistent facilitation of EPSPs evoked in layer II fan cells by layer I stimulation; the size of the facilitation was more variable in pyramidal neurons, and synaptic responses in a small group of multiform neurons were not modulated by dopamine. Isolated inhibitory synaptic responses were not affected by dopamine, and the facilitation of EPSPs was not associated with a change in paired-pulse facilitation ratio. Voltage-clamp recordings of α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) glutamate receptor-mediated excitatory postsynaptic currents (EPSCs) were facilitated by dopamine, but N-methyl-D-aspartate receptor-mediated currents were not. Bath application of the dopamine D₁-like receptor blocker SCH23390 (50 μM), but not the D₂-like receptor blocker sulpiride (50 μM), prevented the facilitation, indicating that it is dependent upon D₁-like receptor activation. Dopamine D₁ receptors lead to activation of protein kinase A (PKA), and including the PKA inhibitor H-89 or KT 5720 in the recording pipette solution prevented the facilitation of EPSCs. PKA-dependent phosphorylation of inhibitor 1 or the dopamine- and cAMP-regulated protein phosphatase (DARPP-32) can lead to a facilitation of AMPA receptor responses by inhibiting the activity of protein phosphatase 1 (PP1) that reduces dephosphorylation of AMPA receptors, and we found here that inhibition of PP1 occluded the facilitatory effect of dopamine. The dopamine

  2. [Oropharyngeal dysphagia and aspiration].

    PubMed

    Barroso, Julia

    2009-11-01

    Oropharyngeal dysphagia, or inability to swallow liquids and/or solids, is one of the less well known geriatric syndromes, despite its enormous impact on functional ability, quality of life and health in affected individuals. The origin of oropharyngeal dysphagia can be structural or functional. Patients with neurodegenerative or cerebrovascular diseases and the frail elderly are the most vulnerable. The complications of oropharyngeal dysphagia are malnutrition, dehydration and aspiration, all of which are serious and provoke high morbidity and mortality. Oropharyngeal aspiration causes frequent respiratory infections and aspiration pneumonias. Antibiotic therapy must cover the usual microorganisms of the oropharyngeal flora. Oropharyngeal dysphagia should be identified early in risk groups through the use of screening methods involving clinical examination of swallowing and diagnostic confirmation methods. The simplest and most effective therapeutic intervention is adaptation of the texture of the solid and the viscosity of the liquid.

  3. Small intestine aspirate and culture

    MedlinePlus

    ... page: //medlineplus.gov/ency/article/003731.htm Small intestine aspirate and culture To use the sharing features on this page, please enable JavaScript. Small intestine aspirate and culture is a lab test to ...

  4. Hydrodynamics of micropipette aspiration.

    PubMed Central

    Drury, J L; Dembo, M

    1999-01-01

    The dynamics of human neutrophils during micropipette aspiration are frequently analyzed by approximating these cells as simple slippery droplets of viscous fluid. Here, we present computations that reveal the detailed predictions of the simplest and most idealized case of such a scheme; namely, the case where the fluid of the droplet is homogeneous and Newtonian, and the surface tension of the droplet is constant. We have investigated the behavior of this model as a function of surface tension, droplet radius, viscosity, aspiration pressure, and pipette radius. In addition, we have tabulated a dimensionless factor, M, which can be utilized to calculate the apparent viscosity of the slippery droplet. Computations were carried out using a low Reynolds number hydrodynamics transport code based on the finite-element method. Although idealized and simplistic, we find that the slippery droplet model predicts many observed features of neutrophil aspiration. However, there are certain features that are not observed in neutrophils. In particular, the model predicts dilation of the membrane past the point of being continuous, as well as a reentrant jet at high aspiration pressures. PMID:9876128

  5. Assessing Children's Career Aspirations

    ERIC Educational Resources Information Center

    Plummer, Donna M.

    2008-01-01

    In the past several years, "Science and Children" has invited preservice and inservice teachers to participate in national studies of students' ideas about scientists (Barman 1997), animals (Barman et al. 2000), and plants (Barman et al. 2003). You are invited to participate in an additional study that will examine children's career aspirations.…

  6. Rising Aspirations Dampen Satisfaction

    ERIC Educational Resources Information Center

    Clark, Andrew E.; Kamesaka, Akiko; Tamura, Teruyuki

    2015-01-01

    It is commonly believed that education is a good thing for individuals. Yet, its correlation with subjective well-being is most often only weakly positive, or even negative, despite the many associated better individual-level outcomes. We here square the circle using novel Japanese data on happiness aspirations. If reported happiness comes from a…

  7. Rising Aspirations Dampen Satisfaction

    ERIC Educational Resources Information Center

    Clark, Andrew E.; Kamesaka, Akiko; Tamura, Teruyuki

    2015-01-01

    It is commonly believed that education is a good thing for individuals. Yet, its correlation with subjective well-being is most often only weakly positive, or even negative, despite the many associated better individual-level outcomes. We here square the circle using novel Japanese data on happiness aspirations. If reported happiness comes from a…

  8. Definition of the orbital cortex in relation to specific connections with limbic and visceral structures and other cortical regions.

    PubMed

    Price, Joseph L

    2007-12-01

    The orbitofrontal cortex is often defined topographically as the cortex on the ventral surface of the frontal lobe. Unfortunately, this definition is not consistently used, and it obscures distinct connectional and functional systems within the orbital cortex. It is difficult to interpret data on the orbital cortex that do not take these different systems into account. Analysis of cortico-cortical connections between areas in the orbital and medial prefrontal cortex indicate two distinct networks in this region. One system, called the orbital network, involves most of the areas in the central orbital cortex. The other system, has been called the medial prefrontal network, though it is actually more complex, since it includes areas on the medial wall, in the medial orbital cortex, and in the posterolateral orbital cortex. Some areas in the medial orbital cortex are involved in both networks. Connections to other brain areas support the distinction between the networks. The orbital network receives several sensory inputs, from olfactory cortex, taste cortex, somatic sensory association cortex, and visual association cortex, and is connected with multisensory areas in the ventrolateral prefrontal cortex and perirhinal cortex. The medial network has outputs to the hypothalamus and brain stem and connects to a cortical circuit that includes the rostral part of the superior temporal gyrus and dorsal bank of the superior temporal sulcus, the cingulate and retrosplenial cortex, the entorhinal and posterior parahippocampal cortex, and the dorsomedial prefrontal cortex.

  9. Direct Electrical Stimulation of the Human Entorhinal Region and Hippocampus Impairs Memory.

    PubMed

    Jacobs, Joshua; Miller, Jonathan; Lee, Sang Ah; Coffey, Tom; Watrous, Andrew J; Sperling, Michael R; Sharan, Ashwini; Worrell, Gregory; Berry, Brent; Lega, Bradley; Jobst, Barbara C; Davis, Kathryn; Gross, Robert E; Sheth, Sameer A; Ezzyat, Youssef; Das, Sandhitsu R; Stein, Joel; Gorniak, Richard; Kahana, Michael J; Rizzuto, Daniel S

    2016-12-07

    Deep brain stimulation (DBS) has shown promise for treating a range of brain disorders and neurological conditions. One recent study showed that DBS in the entorhinal region improved the accuracy of human spatial memory. Based on this line of work, we performed a series of experiments to more fully characterize the effects of DBS in the medial temporal lobe on human memory. Neurosurgical patients with implanted electrodes performed spatial and verbal-episodic memory tasks. During the encoding periods of both tasks, subjects received electrical stimulation at 50 Hz. In contrast to earlier work, electrical stimulation impaired memory performance significantly in both spatial and verbal tasks. Stimulation in both the entorhinal region and hippocampus caused decreased memory performance. These findings indicate that the entorhinal region and hippocampus are causally involved in human memory and suggest that refined methods are needed to use DBS in these regions to improve memory. Copyright © 2016 Elsevier Inc. All rights reserved.

  10. Aspiration and Biopsy: Bone Marrow

    MedlinePlus

    ... 1- to 2-Year-Old Aspiration and Biopsy: Bone Marrow KidsHealth > For Parents > Aspiration and Biopsy: Bone Marrow Print A A A What's in this article? ... Aspiraciones y biopsias: médula ósea What It Is Bone marrow aspirations and biopsies are performed to examine bone ...

  11. Aspiration and Biopsy: Bone Marrow

    MedlinePlus

    ... Your 1- to 2-Year-Old Aspiration and Biopsy: Bone Marrow KidsHealth > For Parents > Aspiration and Biopsy: Bone Marrow A A A What's in this ... ósea What It Is Bone marrow aspirations and biopsies are performed to examine bone marrow, the spongy ...

  12. Aspiration and Biopsy: Bone Marrow

    MedlinePlus

    ... A Week of Healthy Breakfasts Shyness Aspiration and Biopsy: Bone Marrow KidsHealth > For Teens > Aspiration and Biopsy: Bone Marrow A A A What's in this ... Questions What It Is Bone marrow aspirations and biopsies are performed to examine bone marrow, the spongy ...

  13. Declarative association in the perirhinal cortex.

    PubMed

    Naya, Yuji

    2016-12-01

    Declarative memories are our so-called daily language memories, which we are able to describe or explicitly experience through the act of remembering. This conscious recollection makes it possible for us to think about the future based on our previous experience (episodic memory) and knowledge (semantic memory). This cognitive function is substantiated by the medial temporal lobe (MTL), a hierarchically organized complex in which the perirhinal cortex and parahippocampal cortex provide item and context information to the hippocampus via the entorhinal cortex, and the hippocampus plays the main role in association and recollection. This conventional view provides an easily understood structure to the declarative memory system. However, neurophysiological studies reporting the activities of single neurons bring a more complicated view. In this article, I review single-unit studies, particularly those focused on the perirhinal cortex and hippocampus, and suggest that association processes for declarative memory are more distributed over the MTL areas. The perirhinal cortex represents both between-domain associations (e.g., item-reward, item-place and item-time) and within-domain associations (e.g., item-item) and contributes to both subcategories of declarative memory (i.e., episodic and semantic memory) in a way that is complementary with the hippocampus. Copyright © 2016 Elsevier Ireland Ltd and Japan Neuroscience Society. All rights reserved.

  14. Reduced plasticity and mild cognitive impairment-like deficits after entorhinal lesions in hAPP/APOE4 mice.

    PubMed

    Bott, Jean-Bastien; Cosquer, Brigitte; Héraud, Céline; Zerbinatti, Celina; Kelche, Christian; Cassel, Jean-Christophe; Mathis, Chantal

    2013-11-01

    Mild cognitive impairment (MCI) is a clinical condition that often precedes Alzheimer disease (AD). Compared with apolipoprotein E-ε3 (APOE3), the apolipoprotein E-ε4 (APOE4) allele is associated with an increased risk of developing MCI and spatial navigation impairments. In MCI, the entorhinal cortex (EC), which is the main innervation source of the dentate gyrus, displays partial neuronal loss. We show that bilateral partial EC lesions lead to marked spatial memory deficits and reduced synaptic density in the dentate gyrus of APOE4 mice compared with APOE3 mice. Genotype and lesion status did not affect the performance in non-navigational tasks. Thus, partial EC lesions in APOE4 mice were sufficient to induce severe spatial memory impairments and synaptic loss in the dentate gyrus. In addition, lesioned APOE4 mice showed no evidence of reactional increase in cholinergic terminals density as opposed to APOE3 mice, suggesting that APOE4 interferes with the ability of the cholinergic system to respond to EC input loss. These findings provide a possible mechanism underlying the aggravating effect of APOE4 on the cognitive outcome of MCI patients. Copyright © 2013 Elsevier Inc. All rights reserved.

  15. Interhemispheric connections between the infralimbic and entorhinal cortices: The endopiriform nucleus has limbic connections that parallel the sensory and motor connections of the claustrum.

    PubMed

    Watson, Glenn D R; Smith, Jared B; Alloway, Kevin D

    2017-04-15

    We have previously shown that the claustrum is part of an interhemispheric circuit that interconnects somesthetic-motor and visual-motor cortical regions. The role of the claustrum in processing limbic information, however, is poorly understood. Some evidence suggests that the dorsal endopiriform nucleus (DEn), which lies immediately ventral to the claustrum, has connections with limbic cortical areas and should be considered part of a claustrum-DEn complex. To determine whether DEn has similar patterns of cortical connections as the claustrum, we used anterograde and retrograde tracing techniques to elucidate the connectivity of DEn. Following injections of retrograde tracers into DEn, labeled neurons appeared bilaterally in the infralimbic (IL) cortex and ipsilaterally in the entorhinal and piriform cortices. Anterograde tracer injections in DEn revealed labeled terminals in the same cortical regions, but only in the ipsilateral hemisphere. These tracer injections also revealed extensive longitudinal projections throughout the rostrocaudal extent of the nucleus. Dual retrograde tracer injections into IL and lateral entorhinal cortex (LEnt) revealed intermingling of labeled neurons in ipsilateral DEn, including many double-labeled neurons. In other experiments, anterograde and retrograde tracers were separately injected into IL of each hemisphere of the same animal. This revealed an interhemispheric circuit in which IL projects bilaterally to DEn, with the densest terminal labeling appearing in the contralateral hemisphere around retrogradely labeled neurons that project to IL in that hemisphere. By showing that DEn and claustrum have parallel sets of connections, these results suggest that DEn and claustrum perform similar functions in processing limbic and sensorimotor information, respectively. J. Comp. Neurol. 525:1363-1380, 2017. © 2016 Wiley Periodicals, Inc.

  16. Pulmonary aspiration in hospitalized adults.

    PubMed

    Elpern, E H

    1997-02-01

    Until recent years, pulmonary aspiration attracted remarkably little clinical investigation. Although aspiration was considered a common occurrence in hospitalized individuals, with serious and even fatal consequences, clinicians had limited scientific data to guide practice. Consequently, approaches to this problem were based largely on unsystematic observations, intuition, and tradition. Recent investigations on the subjects of aspiration have increased our understanding of patients at risk for aspiration, the value of diagnostic methods, and the efficacy of interventions to prevent or limit aspirations. Results of these studies call to question many time-honored adages and practices. Considerable uncertainty remains and more investigation is necessary before management decisions can be characterized clearly and clinical strategies defined. This review focuses on pulmonary aspiration and enteral feeding in the critically ill adult. Factors implicated in aspiration in this population are highlighted and evidence to support the application of interventions prescribed commonly is presented.

  17. Distinct Spatiotemporal Activation Patterns of the Perirhinal-Entorhinal Network in Response to Cortical and Amygdala Input

    PubMed Central

    Willems, Janske G. P.; Wadman, Wytse J.; Cappaert, Natalie L. M.

    2016-01-01

    The perirhinal (PER) and entorhinal cortex (EC) receive input from the agranular insular cortex (AiP) and the subcortical lateral amygdala (LA) and the main output area is the hippocampus. Information transfer through the PER/EC network however, is not always guaranteed. It is hypothesized that this network actively regulates the (sub)cortical activity transfer to the hippocampal network and that the inhibitory system is involved in this function. This study determined the recruitment by the AiP and LA afferents in PER/EC network with the use of voltage sensitive dye (VSD) imaging in horizontal mouse brain slices. Electrical stimulation (500 μA) of the AiP induced activity that gradually propagated predominantly in the rostro-caudal direction: from the PER to the lateral EC (LEC). In the presence of 1 μM of the competitive γ-aminobutyric acid (GABAA) receptor antagonist bicuculline, AiP stimulation recruited the medial EC (MEC) as well. In contrast, LA stimulation (500 μA) only induced activity in the deep layers of the PER. In the presence of bicuculline, the initial population activity in the PER propagated further towards the superficial layers and the EC after a delay. The latency of evoked responses decreased with increasing stimulus intensities (50–500 μA) for both the AiP and LA stimuli. The stimulation threshold for evoking responses in the PER/EC network was higher for the LA than for the AiP. This study showed that the extent of the PER/EC network activation depends on release of inhibition. When GABAA dependent inhibition is reduced, both the AiP and the LA activate spatially overlapping regions, although in a distinct spatiotemporal fashion. It is therefore hypothesized that the inhibitory network regulates excitatory activity from both cortical and subcortical areas that has to be transmitted through the PER/EC network. PMID:27378860

  18. Accounting for the Confound of Meninges in Segmenting Entorhinal and Perirhinal Cortices in T1-Weighted MRI

    PubMed Central

    Wisse, Laura E.M.; Das, Sandhitsu R.; Wang, Hongzhi; Wolk, David A.; Manjón, Jose V.; Yushkevich, Paul A.

    2017-01-01

    Quantification of medial temporal lobe (MTL) cortices, including entorhinal cortex (ERC) and perirhinal cortex (PRC), from in vivo MRI is desirable for studying the human memory system as well as in early diagnosis and monitoring of Alzheimer’s disease. However, ERC and PRC are commonly over-segmented in T1-weighted (T1w) MRI because of the adjacent meninges that have similar intensity to gray matter in T1 contrast. This introduces errors in the quantification and could potentially confound imaging studies of ERC/PRC. In this paper, we propose to segment MTL cortices along with the adjacent meninges in T1w MRI using an established multi-atlas segmentation framework together with super-resolution technique. Experimental results comparing the proposed pipeline with existing pipelines support the notion that a large portion of meninges is segmented as gray matter by existing algorithms but not by our algorithm. Cross-validation experiments demonstrate promising segmentation accuracy. Further, agreement between the volume and thickness measures from the proposed pipeline and those from the manual segmentations increase dramatically as a result of accounting for the confound of meninges. Evaluated in the context of group discrimination between patients with amnestic mild cognitive impairment and normal controls, the proposed pipeline generates more biologically plausible results and improves the statistical power in discriminating groups in absolute terms comparing to other techniques using T1w MRI. Although the performance of the proposed pipeline is inferior to that using T2-weighted MRI, which is optimized to image MTL sub-structures, the proposed pipeline could still provide important utilities in analyzing many existing large datasets that only have T1w MRI available. PMID:28752156

  19. Accounting for the Confound of Meninges in Segmenting Entorhinal and Perirhinal Cortices in T1-Weighted MRI.

    PubMed

    Xie, Long; Wisse, Laura E M; Das, Sandhitsu R; Wang, Hongzhi; Wolk, David A; Manjón, Jose V; Yushkevich, Paul A

    2016-10-01

    Quantification of medial temporal lobe (MTL) cortices, including entorhinal cortex (ERC) and perirhinal cortex (PRC), from in vivo MRI is desirable for studying the human memory system as well as in early diagnosis and monitoring of Alzheimer's disease. However, ERC and PRC are commonly over-segmented in T1-weighted (T1w) MRI because of the adjacent meninges that have similar intensity to gray matter in T1 contrast. This introduces errors in the quantification and could potentially confound imaging studies of ERC/PRC. In this paper, we propose to segment MTL cortices along with the adjacent meninges in T1w MRI using an established multi-atlas segmentation framework together with super-resolution technique. Experimental results comparing the proposed pipeline with existing pipelines support the notion that a large portion of meninges is segmented as gray matter by existing algorithms but not by our algorithm. Cross-validation experiments demonstrate promising segmentation accuracy. Further, agreement between the volume and thickness measures from the proposed pipeline and those from the manual segmentations increase dramatically as a result of accounting for the confound of meninges. Evaluated in the context of group discrimination between patients with amnestic mild cognitive impairment and normal controls, the proposed pipeline generates more biologically plausible results and improves the statistical power in discriminating groups in absolute terms comparing to other techniques using T1w MRI. Although the performance of the proposed pipeline is inferior to that using T2-weighted MRI, which is optimized to image MTL sub-structures, the proposed pipeline could still provide important utilities in analyzing many existing large datasets that only have T1w MRI available.

  20. Influence of secondary aspiration on human aspiration efficiency.

    PubMed

    Anderson, K R; Anthony, T Renee

    2014-09-01

    Computational fluid dynamics (CFD) was used to evaluate the contribution of secondary aspiration to human aspiration efficiency estimates using a humanoid model with realistic facial features. This study applied coefficient of restitution (CoR) values for working-aged human facial skin to the facial regions on the humanoid CFD model. Aspiration efficiencies for particles ranging from 7 to 116 μm were estimated for bounce (allowing for secondary aspiration) and no-bounce (CoR=0) simulations. Fluid simulations used the standard k-epsilon turbulence model over a range of test conditions: three freestream velocities, two breathing modes (mouth and nose breathing, using constant inhalation), three breathing velocities, and five orientations relative to the oncoming wind. Laminar particle trajectory simulations were used to examine inhaled particle transport and estimate aspiration efficiencies. Aspiration efficiency for the realistic CoR simulations, for both mouth- and nose-breathing, decreased with increasing particle size, with aspiration around 50% for 116 μm particles. For the CoR=0 simulations, aspiration decreased more rapidly with increasing particle size and approached zero for 116 μm compared to realistic CoR models (differences ranged from 0% to 80% over the particle sizes and velocity conditions). Differences in aspiration efficiency were larger with increasing particle size (>52 μm) and increased with decreasing freestream velocity and decreasing breathing rate. Secondary aspiration was more important when the humanoid faced the wind, but these contributions to overall aspiration estimates decreased as the humanoid rotated through 90°. There were minimal differences in aspiration between uniform CoR values of 0.5, 0.8, 1.0 and realistic regionally-applied CoR values, indicating differences between mannequin surfaces and between mannequin and human skin will have negligible effect on aspiration for facing-the-wind orientation.

  1. Influence of secondary aspiration on human aspiration efficiency

    PubMed Central

    Anderson, K.R.; Anthony, T. Renee

    2016-01-01

    Computational fluid dynamics (CFD) was used to evaluate the contribution of secondary aspiration to human aspiration efficiency estimates using a humanoid model with realistic facial features. This study applied coefficient of restitution (CoR) values for working-aged human facial skin to the facial regions on the humanoid CFD model. Aspiration efficiencies for particles ranging from 7 to 116 μm were estimated for bounce (allowing for secondary aspiration) and no-bounce (CoR=0) simulations. Fluid simulations used the standard k–epsilon turbulence model over a range of test conditions: three freestream velocities, two breathing modes (mouth and nose breathing, using constant inhalation), three breathing velocities, and five orientations relative to the oncoming wind. Laminar particle trajectory simulations were used to examine inhaled particle transport and estimate aspiration efficiencies. Aspiration efficiency for the realistic CoR simulations, for both mouth- and nose-breathing, decreased with increasing particle size, with aspiration around 50% for 116 μm particles. For the CoR=0 simulations, aspiration decreased more rapidly with increasing particle size and approached zero for 116 μm compared to realistic CoR models (differences ranged from 0% to 80% over the particle sizes and velocity conditions). Differences in aspiration efficiency were larger with increasing particle size (>52 μm) and increased with decreasing freestream velocity and decreasing breathing rate. Secondary aspiration was more important when the humanoid faced the wind, but these contributions to overall aspiration estimates decreased as the humanoid rotated through 90°. There were minimal differences in aspiration between uniform CoR values of 0.5, 0.8, 1.0 and realistic regionally-applied CoR values, indicating differences between mannequin surfaces and between mannequin and human skin will have negligible effect on aspiration for facing-the-wind orientation. PMID:26778849

  2. Aspirated High Pressure Compressor

    DTIC Science & Technology

    2006-08-01

    Std. Z39.18 A proved for Public Release Distribution Unlimited ABSTRACT (continued from Blockl4) within 0.5 percentage points . High response static...attention was given to the design of the instrumentation to obtain efficiency measurements within 0.5 percentage points . High response static pressure...prior empirical knowledge [3]. 0.5 percentage points . High response static pressure The new proposition addressed here is that aspiration offers

  3. Musculoskeletal Aspiration Procedures

    PubMed Central

    Hansford, Barry Glenn; Stacy, Gregory Scott

    2012-01-01

    With advances in imaging technology, there has been a significant increase in the number and range of interventional musculoskeletal image-guided procedures. One of the most commonly performed image-guided musculoskeletal interventions is the diagnostic and therapeutic percutaneous aspiration and drainage of multiple types of intra-articular, juxta-articular, and intramuscular pathologic fluid collections. These procedures may be performed under fluoroscopic, ultrasound, computed tomography, or even magnetic resonance guidance depending on the location to be accessed, type of pathology, patient characteristics, and operator preference. Musculoskeletal image-guided aspiration and drainage procedures are minimally invasive and generally very safe while offering valuable diagnostic information as well as therapeutic benefit. This article focuses on the appropriate indications, contraindications, and general technique for accessing the major joints via imaging guidance. For each joint, we discuss pertinent anatomy, appropriate imaging modalities, and preferred approaches to gaining intra-articular access. Additionally, the article discusses some of the more frequently encountered juxta-articular and intramuscular fluid collections that can be accessed and aspirated via percutaneous intervention, with mention of the importance of recognizing extremity sarcomas that can mimic these benign collections. PMID:24293800

  4. Lateralized Spatial and Object Memory Encoding in Entorhinal and Perirhinal Cortices

    ERIC Educational Resources Information Center

    Bellgowan, Patrick S. F.; Buffalo, Elizabeth A.; Bodurka, Jerzy; Martin, Alex

    2009-01-01

    The perirhinal and entorhinal cortices are critical components of the medial temporal lobe (MTL) declarative memory system. Study of their specific functions using blood oxygenation level-dependent (BOLD) functional magnetic resonance imaging (fMRI), however, has suffered from severe magnetic susceptibility signal dropout resulting in poor…

  5. Perirhinal and Postrhinal, but Not Lateral Entorhinal, Cortices Are Essential for Acquisition of Trace Eyeblink Conditioning

    ERIC Educational Resources Information Center

    Suter, Eugenie E.; Weiss, Craig; Disterhoft, John F.

    2013-01-01

    The acquisition of temporal associative tasks such as trace eyeblink conditioning is hippocampus-dependent, while consolidated performance is not. The parahippocampal region mediates much of the input and output of the hippocampus, and perirhinal (PER) and entorhinal (EC) cortices support persistent spiking, a possible mediator of temporal…

  6. Lateralized Spatial and Object Memory Encoding in Entorhinal and Perirhinal Cortices

    ERIC Educational Resources Information Center

    Bellgowan, Patrick S. F.; Buffalo, Elizabeth A.; Bodurka, Jerzy; Martin, Alex

    2009-01-01

    The perirhinal and entorhinal cortices are critical components of the medial temporal lobe (MTL) declarative memory system. Study of their specific functions using blood oxygenation level-dependent (BOLD) functional magnetic resonance imaging (fMRI), however, has suffered from severe magnetic susceptibility signal dropout resulting in poor…

  7. Perirhinal and Postrhinal, but Not Lateral Entorhinal, Cortices Are Essential for Acquisition of Trace Eyeblink Conditioning

    ERIC Educational Resources Information Center

    Suter, Eugenie E.; Weiss, Craig; Disterhoft, John F.

    2013-01-01

    The acquisition of temporal associative tasks such as trace eyeblink conditioning is hippocampus-dependent, while consolidated performance is not. The parahippocampal region mediates much of the input and output of the hippocampus, and perirhinal (PER) and entorhinal (EC) cortices support persistent spiking, a possible mediator of temporal…

  8. Perirhinal cortex and temporal lobe epilepsy.

    PubMed

    Biagini, Giuseppe; D'Antuono, Margherita; Benini, Ruba; de Guzman, Philip; Longo, Daniela; Avoli, Massimo

    2013-08-29

    The perirhinal cortex-which is interconnected with several limbic structures and is intimately involved in learning and memory-plays major roles in pathological processes such as the kindling phenomenon of epileptogenesis and the spread of limbic seizures. Both features may be relevant to the pathophysiology of mesial temporal lobe epilepsy that represents the most refractory adult form of epilepsy with up to 30% of patients not achieving adequate seizure control. Compared to other limbic structures such as the hippocampus or the entorhinal cortex, the perirhinal area remains understudied and, in particular, detailed information on its dysfunctional characteristics remains scarce; this lack of information may be due to the fact that the perirhinal cortex is not grossly damaged in mesial temporal lobe epilepsy and in models mimicking this epileptic disorder. However, we have recently identified in pilocarpine-treated epileptic rats the presence of selective losses of interneuron subtypes along with increased synaptic excitability. In this review we: (i) highlight the fundamental electrophysiological properties of perirhinal cortex neurons; (ii) briefly stress the mechanisms underlying epileptiform synchronization in perirhinal cortex networks following epileptogenic pharmacological manipulations; and (iii) focus on the changes in neuronal excitability and cytoarchitecture of the perirhinal cortex occurring in the pilocarpine model of mesial temporal lobe epilepsy. Overall, these data indicate that perirhinal cortex networks are hyperexcitable in an animal model of temporal lobe epilepsy, and that this condition is associated with a selective cellular damage that is characterized by an age-dependent sensitivity of interneurons to precipitating injuries, such as status epilepticus.

  9. Fine needle aspiration cytology.

    PubMed Central

    Lever, J V; Trott, P A; Webb, A J

    1985-01-01

    Fine needle aspiration cytology is an inexpensive, atraumatic technique for the diagnosis of disease sites. This paper describes the technique and illustrates how it may be applied to the management of tumours throughout the body. The limitations of the method, the dangers of false positive reports, and the inevitability of false negative diagnoses are emphasised. In a clinical context the method has much to offer by saving patients from inappropriate operations and investigations and allowing surgeons to plan quickly and more rationally. It is an economically valuable technique and deserves greater recognition. Images PMID:2578481

  10. Specific Metabolomics Adaptations Define a Differential Regional Vulnerability in the Adult Human Cerebral Cortex.

    PubMed

    Cabré, Rosanna; Jové, Mariona; Naudí, Alba; Ayala, Victoria; Piñol-Ripoll, Gerard; Gil-Villar, Maria P; Dominguez-Gonzalez, Mayelin; Obis, Èlia; Berdun, Rebeca; Mota-Martorell, Natalia; Portero-Otin, Manuel; Ferrer, Isidre; Pamplona, Reinald

    2016-01-01

    Brain neurons offer diverse responses to stresses and detrimental factors during development and aging, and as a result of both neurodegenerative and neuropsychiatric disorders. This multiplicity of responses can be ascribed to the great diversity among neuronal populations. Here we have determined the metabolomic profile of three healthy adult human brain regions-entorhinal cortex, hippocampus, and frontal cortex-using mass spectrometry-based technologies. Our results show the existence of a lessened energy demand, mitochondrial stress, and lower one-carbon metabolism (particularly restricted to the methionine cycle) specifically in frontal cortex. These findings, along with the better antioxidant capacity and lower mTOR signaling also seen in frontal cortex, suggest that this brain region is especially resistant to stress compared to the entorhinal cortex and hippocampus, which are more vulnerable regions. Globally, our results show the presence of specific metabolomics adaptations in three mature, healthy human brain regions, confirming the existence of cross-regional differences in cell vulnerability in the human cerebral cortex.

  11. Cytoarchitecture, neuronal composition, and entorhinal afferents of the flying fox hippocampus.

    PubMed

    Buhl, E H; Dann, J F

    1991-04-01

    In a comparative approach, the anatomical organization of the hippocampus was investigated in two species of megachiropteran bats, the grey-headed flying fox, Pteropus poliocephalus, and the little red flying fox, Pteropus scapulatus. In general, the cytoarchitectonic appearance of the flying fox hippocampus corresponded well with that of other mammals, revealing all major subdivisions. While the dentate fascia was trilaminated with a molecular layer, a granule cell layer, and a distinct polymorphic layer, the ammonic subfields were subdivided into stratum lacunosum molecular, stratum radiatum, stratum lucidum or mossy fiber layer (restricted to the CA3 region), pyramidal cell layer, and stratum oriens. In Ammon's horn, only subfields CA1, CA3, and CA3c were clearly discernible, whereas the CA2 region remained indistinct. In some cytoarchitectonic features, such as the dispersion of the pyramidal layer in CA1, the megachiropteran hippocampus resembled the corresponding region in primates. Five characteristic neuronal cell types of the megachiropteran hippocampus were studied in fixed slice preparations after intracellular injection with Lucifer Yellow. While the morphological appearance of CA3 pyramidal cells, horizontal stratum oriens cells, aspiny stellate cells, and mossy cells strongly resembled their counterparts in rodents, primates, and carnivores, granule cells showed an interesting variation from the nonprimate pattern. Like a subset of granule cells in the primate dentate gyrus, 75% of flying fox granule cells revealed 1-2 basal dendrites that ramified in the polymorphic layer. These processes are presumed to form the morphological substrate for recurrent excitation. Entorhinal afferents to Ammon's horn and the dentate fascia were revealed by employing the method of tract tracing in fixed tissue with the carbocyanine dye DiI. Similar to the rat and cat, but unlike the monkey, the entorhino-dentate projection in the flying fox is bilaminate, with medial

  12. How reduction of theta rhythm by medial septum inactivation may covary with disruption of entorhinal grid cell responses due to reduced cholinergic transmission.

    PubMed

    Pilly, Praveen K; Grossberg, Stephen

    2013-01-01

    Oscillations in the coordinated firing of brain neurons have been proposed to play important roles in perception, cognition, attention, learning, navigation, and sensory-motor control. The network theta rhythm has been associated with properties of spatial navigation, as has the firing of entorhinal grid cells and hippocampal place cells. Two recent studies reduced the theta rhythm by inactivating the medial septum (MS) and demonstrated a correlated reduction in the characteristic hexagonal spatial firing patterns of grid cells. These results, along with properties of intrinsic membrane potential oscillations (MPOs) in slice preparations of medial entorhinal cortex (MEC), have been interpreted to support oscillatory interference models of grid cell firing. The current article shows that an alternative self-organizing map (SOM) model of grid cells can explain these data about intrinsic and network oscillations without invoking oscillatory interference. In particular, the adverse effects of MS inactivation on grid cells can be understood in terms of how the concomitant reduction in cholinergic inputs may increase the conductances of leak potassium (K(+)) and slow and medium after-hyperpolarization (sAHP and mAHP) channels. This alternative model can also explain data that are problematic for oscillatory interference models, including how knockout of the HCN1 gene in mice, which flattens the dorsoventral gradient in MPO frequency and resonance frequency, does not affect the development of the grid cell dorsoventral gradient of spatial scales, and how hexagonal grid firing fields in bats can occur even in the absence of theta band modulation. These results demonstrate how models of grid cell self-organization can provide new insights into the relationship between brain learning and oscillatory dynamics.

  13. GEAR UP Aspirations Project Evaluation

    ERIC Educational Resources Information Center

    Trimble, Brad A.

    2013-01-01

    The purpose of this study was to conduct a formative evaluation of the first two years of the Gaining Early Awareness and Readiness for Undergraduate Programs (GEAR UP) Aspirations Project (Aspirations) using a Context, Input, Process, and Product (CIPP) model so as to gain an in-depth understanding of the project during the middle school…

  14. Death following crude oil aspiration.

    PubMed

    Rodriguez, M A; Martinez, M C; Martinez-Ruiz, D; Paz Giménez, M; Menéndez, M; Repetto, M

    1991-07-01

    This is a report on three deaths following oil aspiration by workers in petrol tankers. Lung aspiration was demonstrated by the presence of a yellowish-brown material in the alveolar spaces, which was difficult to identify by optic microscopy. Volatile hydrocarbons from petroleum were identified in lung samples by gas chromatography/mass spectrometry.

  15. GEAR UP Aspirations Project Evaluation

    ERIC Educational Resources Information Center

    Trimble, Brad A.

    2013-01-01

    The purpose of this study was to conduct a formative evaluation of the first two years of the Gaining Early Awareness and Readiness for Undergraduate Programs (GEAR UP) Aspirations Project (Aspirations) using a Context, Input, Process, and Product (CIPP) model so as to gain an in-depth understanding of the project during the middle school…

  16. Educational Aspirations Trajectories in England

    ERIC Educational Resources Information Center

    McCulloch, Andrew

    2017-01-01

    This study used latent class analysis to examine the trajectories followed by young people's educational aspirations in England over the age range from 13 to 16 years and their relationship to educational achievement. The results suggested that young people's aspirations followed six trajectories. Four trajectories showed overall patterns of…

  17. Perirhinal cortex and temporal lobe epilepsy

    PubMed Central

    Biagini, Giuseppe; D'Antuono, Margherita; Benini, Ruba; de Guzman, Philip; Longo, Daniela; Avoli, Massimo

    2013-01-01

    The perirhinal cortex—which is interconnected with several limbic structures and is intimately involved in learning and memory—plays major roles in pathological processes such as the kindling phenomenon of epileptogenesis and the spread of limbic seizures. Both features may be relevant to the pathophysiology of mesial temporal lobe epilepsy that represents the most refractory adult form of epilepsy with up to 30% of patients not achieving adequate seizure control. Compared to other limbic structures such as the hippocampus or the entorhinal cortex, the perirhinal area remains understudied and, in particular, detailed information on its dysfunctional characteristics remains scarce; this lack of information may be due to the fact that the perirhinal cortex is not grossly damaged in mesial temporal lobe epilepsy and in models mimicking this epileptic disorder. However, we have recently identified in pilocarpine-treated epileptic rats the presence of selective losses of interneuron subtypes along with increased synaptic excitability. In this review we: (i) highlight the fundamental electrophysiological properties of perirhinal cortex neurons; (ii) briefly stress the mechanisms underlying epileptiform synchronization in perirhinal cortex networks following epileptogenic pharmacological manipulations; and (iii) focus on the changes in neuronal excitability and cytoarchitecture of the perirhinal cortex occurring in the pilocarpine model of mesial temporal lobe epilepsy. Overall, these data indicate that perirhinal cortex networks are hyperexcitable in an animal model of temporal lobe epilepsy, and that this condition is associated with a selective cellular damage that is characterized by an age-dependent sensitivity of interneurons to precipitating injuries, such as status epilepticus. PMID:24009554

  18. Abdominal intrauterine vacuum aspiration.

    PubMed

    Tjalma, W A A

    2014-01-01

    Evaluating and "cleaning" of the uterine cavity is probably the most performed operation in women. It is done for several reasons: abortion, evaluation of irregular bleeding in premenopausal period, and postmenopausal bleeding. Abortion is undoubtedly the number one procedure with more than 44 million pregnancies terminated every year. This procedure should not be underestimated and a careful preoperative evaluation is needed. Ideally a sensitive pregnancy test should be done together with an ultrasound in order to confirm a uterine pregnancy, excluding extra-uterine pregnancy, and to detect genital and/or uterine malformations. Three out of four abortions are performed by surgical methods. Surgical methods include a sharp, blunt, and suction curettage. Suction curettage or vacuum aspiration is the preferred method. Despite the fact that it is a relative safe procedure with major complications in less than one percent of cases, it is still responsible for 13% of all maternal deaths. All the figures have not declined in the last decade. Trauma, perforation, and bleeding are a danger triage. When there is a perforation, a laparoscopy should be performed immediately, in order to detect intra-abdominal lacerations and bleeding. The bleeding should be stopped as soon as possible in order to not destabilize the patient. When there is a perforation in the uterus, this "entrance" can be used to perform the curettage. This is particularly useful if there is trauma of the isthmus and uterine wall, and it is difficult to identify the uterine canal. A curettage is a frequent performed procedure, which should not be underestimated. If there is a perforation in the uterus, then this opening can safely be used for vacuum aspiration.

  19. Specific Metabolomics Adaptations Define a Differential Regional Vulnerability in the Adult Human Cerebral Cortex

    PubMed Central

    Cabré, Rosanna; Jové, Mariona; Naudí, Alba; Ayala, Victoria; Piñol-Ripoll, Gerard; Gil-Villar, Maria P.; Dominguez-Gonzalez, Mayelin; Obis, Èlia; Berdun, Rebeca; Mota-Martorell, Natalia; Portero-Otin, Manuel; Ferrer, Isidre; Pamplona, Reinald

    2016-01-01

    Brain neurons offer diverse responses to stresses and detrimental factors during development and aging, and as a result of both neurodegenerative and neuropsychiatric disorders. This multiplicity of responses can be ascribed to the great diversity among neuronal populations. Here we have determined the metabolomic profile of three healthy adult human brain regions—entorhinal cortex, hippocampus, and frontal cortex—using mass spectrometry-based technologies. Our results show the existence of a lessened energy demand, mitochondrial stress, and lower one-carbon metabolism (particularly restricted to the methionine cycle) specifically in frontal cortex. These findings, along with the better antioxidant capacity and lower mTOR signaling also seen in frontal cortex, suggest that this brain region is especially resistant to stress compared to the entorhinal cortex and hippocampus, which are more vulnerable regions. Globally, our results show the presence of specific metabolomics adaptations in three mature, healthy human brain regions, confirming the existence of cross-regional differences in cell vulnerability in the human cerebral cortex. PMID:28008307

  20. Aspiration of the retrocalcaneal bursa.

    PubMed Central

    Canoso, J J; Wohlgethan, J R; Newberg, A H; Goldsmith, M R

    1984-01-01

    We aspirated the retrocalcaneal bursa in cadavers to determine the characteristics of bursal fluid. A small amount of clear, viscous fluid was constantly present in the bursa. Leucocyte count was low, and the mucin clot test was good. With the same technique we aspirated the retrocalcaneal bursae of 4 patients. Three had Reiter's syndrome; the bursal fluid was inflammatory, and symptoms promptly resolved after local corticosteroid injection. The fourth patient presented with heel pain; intracellular, positively birefringent crystals were present in the aspirate, consistent with the diagnosis of pseudogout. Images PMID:6712303

  1. The Embryonic Septum and Ventral Pallium, New Sources of Olfactory Cortex Cells

    PubMed Central

    de Carlos, Juan A.

    2012-01-01

    The mammalian olfactory cortex is a complex structure located along the rostro-caudal extension of the ventrolateral prosencephalon, which is divided into several anatomically and functionally distinct areas: the anterior olfactory nucleus, piriform cortex, olfactory tubercle, amygdaloid olfactory nuclei, and the more caudal entorhinal cortex. Multiple forebrain progenitor domains contribute to the cellular diversity of the olfactory cortex, which is invaded simultaneously by cells originating in distinct germinal areas in the dorsal and ventral forebrain. Using a combination of dye labeling techniques, we identified two novel areas that contribute cells to the developing olfactory cortices, the septum and the ventral pallium, from which cells migrate along a radial and then a tangential path. We characterized these cell populations by comparing their expression of calretinin, calbindin, reelin and Tbr1 with that of other olfactory cell populations. PMID:22984546

  2. Supersymmetry: aspirations and prospects

    NASA Astrophysics Data System (ADS)

    Tata, Xerxes

    2015-10-01

    The realization in the early 1980s that weak scale supersymmetry stabilizes the Higgs sector of the spectacularly successful Standard Model (SM) led several authors to explore whether low energy supersymmetry could play a role in particle physics. Among these were Richard Arnowitt, Ali Chamseddine and Pran Nath who constructed a viable locally supersymmetric grand unified theory (GUT), laying down the foundation for supergravity GUT models of particle physics. Supergravity models continue to be explored as one of the most promising extensions of the SM. After a quick overview of some of the issues and aspirations of early researchers working to bring supersymmetry into the mainstream of particle physics, we re-examine early arguments that seemed to imply that superpartners would be revealed in experiments at LEP2 or at the Tevatron. Our purpose is to assess whether the absence of any superpartners in searches at LHC8 presents a crisis for supersymmetry. Toward this end, we re-evaluate fine-tuning arguments that lead to upper bounds on (some) superpartner masses. We conclude that phenomenologically viable superpartner spectra that could arise within a high scale model tuned no worse than a few percent are perfectly possible. While no viable underlying model of particle physics that leads to such spectra has yet emerged, we show that the (supergravity-based) radiatively driven natural supersymmetry framework serves as a surrogate for a phenomenological analysis of an underlying theory with modest fine-tuning. We outline the phenomenological implications of this framework, with emphasis on those LHC and electron-positron collider signatures that might point to the underlying natural origin of gauge and Higgs boson masses. We conclude that the supergravity GUT paradigm laid down in 1982 by Arnowitt, Chamseddine and Nath, and others, remains a vibrant possibility.

  3. The orbitofrontal cortex: novelty, deviation from expectation, and memory.

    PubMed

    Petrides, Michael

    2007-12-01

    The orbitofrontal cortex is strongly connected with limbic areas of the medial temporal lobe that are critically involved in the establishment of declarative memories (entorhinal and perirhinal cortex and the hippocampal region) as well as the amygdala and the hypothalamus that are involved in emotional and motivational states. The present article reviews evidence regarding the role of the orbitofrontal cortex in the processing of novel information, breaches of expectation, and memory. Functional neuroimaging evidence is provided that there is a difference between the anterior and posterior orbitofrontal cortex in such processing. Exposure to novel information gives rise to a selective increase of activity in the granular anterior part of the orbitofrontal cortex (area 11) and this activity increases when subjects attempt to encode this information in memory. If the stimuli violate expectations (e.g., inspection of graffiti-like stimuli in the context of other regular stimuli) or are unpleasant (i.e., exposure to the sounds of car crashes), there is increased response in the posteromedial agranular/dysgranular area 13 of the orbitofrontal region. The anatomic data provide a framework within which to understand these functional neuroimaging findings.

  4. [Perioperative Pulmonary Aspiration: Preface and Comments].

    PubMed

    Asai, Takashi

    2016-01-01

    Since the risk of pulmonary aspiration was recognized in obstetric anesthesia in 1930's, numerous efforts have been made to reduce the incidence and severity of perioperative pulmonary aspiration: preoperative fasting, preoperative assessment of risk factors in perioperative pulmonary aspiration, emptying the stomach, rapid-sequence induction of anesthesia with cricoid pressure, and the use of a cuffed tracheal tube. With these efforts, the incidence of pulmonary aspiration has been reduced drastically, and aspiration is now rare. Nevertheless, recent large studies have shown that perioperative pulmonary aspiration is the main cause of anesthesia-related death or irreversible brain damage. In this special issue, experts summarize the current state of perioperative pulmonary aspiration, its diagnosis and treatment, risk factors of pulmonary aspiration, preoperative preventative methods, and appropriate anesthesia methods and airway management in patients at increased risk of pulmonary aspiration.

  5. Pulmonary aspiration of gastric contents.

    PubMed

    Bynum, L J; Pierce, A K

    1976-12-01

    A retrospective analysis of 50 patients who had been observed to aspirate gastric contents was performed to define better the course of patients with this syndrome. The patients invariably had a disturbance of consciousness, most commonly due to sedative drug overdose or general anesthesia. The onset of clinical signs occurred prompty after aspiration and tended to be similar in all patients, irrespective of their subsequent course or outcome. These findings usually included fever, tachypnea, diffuse rales, and serious hypoxemia. Cough, cyanosis, wheezing, and apnea were each seen in approximately one third of the cases. Apena, shock, and early severe hypoxemia were particularly ominous events. Initial roentgenograms revealed diffuse or localized alveolar infiltrates, which progressed during the next 24 to 36 hours. Subsequent clinical courses followed 3 patterns: 12 per cent of the patients died shortly after aspiration; 62 per cent had rapid clinical and radiologic improvement, with clearing, on average, within 4.5 days; 26 per cent demonstrated rapid improvement, but then had clinical and radiographic progression associated with recovery of bacterial pathogens from the sputum and a fatal outcome in more than 60 per cent. Treatment from the outset by adrenocortical steroids or antimicrobial agents had no demonstrable effect on the outcome. The clinical features of aspiration of gastric contents are characteristic and distinguish it from other forms of aspiration-related lung disease.

  6. Entorhinal-CA3 Dual-Input Control of Spike Timing in the Hippocampus by Theta-Gamma Coupling.

    PubMed

    Fernández-Ruiz, Antonio; Oliva, Azahara; Nagy, Gergő A; Maurer, Andrew P; Berényi, Antal; Buzsáki, György

    2017-03-08

    Theta-gamma phase coupling and spike timing within theta oscillations are prominent features of the hippocampus and are often related to navigation and memory. However, the mechanisms that give rise to these relationships are not well understood. Using high spatial resolution electrophysiology, we investigated the influence of CA3 and entorhinal inputs on the timing of CA1 neurons. The theta-phase preference and excitatory strength of the afferent CA3 and entorhinal inputs effectively timed the principal neuron activity, as well as regulated distinct CA1 interneuron populations in multiple tasks and behavioral states. Feedback potentiation of distal dendritic inhibition by CA1 place cells attenuated the excitatory entorhinal input at place field entry, coupled with feedback depression of proximal dendritic and perisomatic inhibition, allowing the CA3 input to gain control toward the exit. Thus, upstream inputs interact with local mechanisms to determine theta-phase timing of hippocampal neurons to support memory and spatial navigation.

  7. [Aspiration biopsy of the pancreas].

    PubMed

    Pérez Catzín, F; Gutiérrez Samperio, C; Valenzuela Tamariz, J

    1979-01-01

    Biopsy of the pancreas frequently is followed by complications, this is why the transoperative aspiration biopsy has been recomended. During the last 2 years we used this procedure in 46 patients; in each case, one or several aspirations were done in the more-representative area of the pancreatic pathology. With the aspirated material a smear was fixed and treated with H-E stain. Biopsy was negative for carcinoma in 30 patients (65.2%), positive in 12 (26.0%), insuficient material results in other 4 (8.6%) we consider that the procedure was useful in the 82.6% of the cases and help to elect more adecuate surgical tecnic. There were no complications and we concluded that this is not a harmful procedure. The correct interpretation of the citology depends on the experience of the pathologyst with this method, to increase the percentage of correct diagnosis.

  8. [Prevention of Perioperative Aspiration Pneumonitis].

    PubMed

    Fukuda, Kazuhiko

    2016-01-01

    To prevent perioperative aspiration pneumonitis, it is necessary to reduce the volume and acidity of gastric content. The guideline for preoperative fasting published by Japanese Society of Anesthesiologists recommends fasting from intake of clear fluids, breast milk and nonhuman milk at least 2h, 4h and 6h, respectively, before elective procedures requiring general anesthesia, regional anesthesia or sedation/analgesia. Gastrointestinal stimulants, histamine-2 receptor antagonists, proton pump inhibitors, antacids, antiemetics, anticholinergics are effective for reduction of the volume or acidity of gastric content. However, the routine preoperative use of these drugs to reduce the risk of pulmonary aspiration in patients who have no apparent increased risk for pulmonary aspiration is not recommended.

  9. Preventing Effect of L-Type Calcium Channel Blockade on Electrophysiological Alterations in Dentate Gyrus Granule Cells Induced by Entorhinal Amyloid Pathology

    PubMed Central

    Pourbadie, Hamid Gholami; Naderi, Nima; Mehranfard, Nasrin; Janahmadi, Mahyar; Khodagholi, Fariba; Motamedi, Fereshteh

    2015-01-01

    The entorhinal cortex (EC) is one of the earliest affected brain regions in Alzheimer’s disease (AD). EC-amyloid pathology induces synaptic failure in the dentate gyrus (DG) with resultant behavioral impairment, but there is little known about its impact on neuronal properties in the DG. It is believed that calcium dyshomeostasis plays a pivotal role in the etiology of AD. Here, the effect of the EC amyloid pathogenesis on cellular properties of DG granule cells and also possible neuroprotective role of L-type calcium channel blockers (CCBs), nimodipine and isradipine, were investigated. The amyloid beta (Aβ) 1–42 was injected bilaterally into the EC of male rats and one week later, electrophysiological properties of DG granule cells were assessed. Voltage clamp recording revealed appearance of giant sIPSC in combination with a decrease in sEPSC frequency which was partially reversed by CCBs in granule cells from Aβ treated rats. EC amyloid pathogenesis induced a significant reduction of input resistance (Rin) accompanied by a profound decreased excitability in the DG granule cells. However, daily administration of CCBs, isradipine or nimodipine (i.c.v. for 6 days), almost preserved the normal excitability against Aβ. In conclusion, lower tendency to fire AP along with reduced Rin suggest that DG granule cells might undergo an alteration in the membrane ion channel activities which finally lead to the behavioral deficits observed in animal models and patients with early-stage Alzheimer’s disease. PMID:25689857

  10. Human P301L-Mutant Tau Expression in Mouse Entorhinal-Hippocampal Network Causes Tau Aggregation and Presynaptic Pathology but No Cognitive Deficits

    PubMed Central

    Harris, Julie A.; Koyama, Akihiko; Maeda, Sumihiro; Ho, Kaitlyn; Devidze, Nino; Dubal, Dena B.; Yu, Gui-Qiu; Masliah, Eliezer; Mucke, Lennart

    2012-01-01

    Accumulation of hyperphosphorylated tau in the entorhinal cortex (EC) is one of the earliest pathological hallmarks in patients with Alzheimer’s disease (AD). It can occur before significant Aβ deposition and appears to “spread” into anatomically connected brain regions. To determine whether this early-stage pathology is sufficient to cause disease progression and cognitive decline in experimental models, we overexpressed mutant human tau (hTauP301L) predominantly in layer II/III neurons of the mouse EC. Cognitive functions remained normal in mice at 4, 8, 12 and 16 months of age, despite early and extensive tau accumulation in the EC. Perforant path (PP) axon terminals within the dentate gyrus (DG) contained abnormal conformations of tau even in young EC-hTau mice, and phosphorylated tau increased with age in both the EC and PP. In old mice, ultrastructural alterations in presynaptic terminals were observed at PP-to-granule cell synapses. Phosphorylated tau was more abundant in presynaptic than postsynaptic elements. Human and pathological tau was also detected within hippocampal neurons of this mouse model. Thus, hTauP301L accumulation predominantly in the EC and related presynaptic pathology in hippocampal circuits was not sufficient to cause robust cognitive deficits within the age range analyzed here. PMID:23029293

  11. Convergence of entorhinal and CA3 inputs onto pyramidal neurons and interneurons in hippocampal area CA1--an anatomical study in the rat.

    PubMed

    Kajiwara, Riichi; Wouterlood, Floris G; Sah, Anupam; Boekel, Amber J; Baks-te Bulte, Luciënne T G; Witter, Menno P

    2008-01-01

    The entorhinal cortex (EC) conveys information to hippocampal field CA1 either directly by way of projections from principal neurons in layer III, or indirectly by axons from layer II via the dentate gyrus, CA3, and Schaffer collaterals. These two pathways differentially influence activity in CA1, yet conclusive evidence is lacking whether and to what extent they converge onto single CA1 neurons. Presently we studied such convergence. Different neuroanatomical tracers injected into layer III of EC and into CA3, respectively, tagged simultaneously the direct entorhino-hippocampal fibers and the indirect innervation of CA1 neurons by Schaffer collaterals. In slices of fixed brains we intracellularly filled CA1 pyramidal cells and interneurons in stratum lacunosum-moleculare (LM) and stratum radiatum (SR). Sections of these slices were scanned in a confocal laser scanning microscope. 3D-reconstruction was used to determine whether boutons of the labeled input fibers were in contact with the intracellularly filled neurons. We analyzed 12 pyramidal neurons and 21 interneurons. Perforant path innervation to pyramidal neurons in our material was observed to be denser than that from CA3. All pyramidal neurons and 17 of the interneurons received contacts of both perforant pathway and Schaffer input on their dendrites and cell bodies. Four interneurons, which were completely embedded in LM, received only labeled perforant pathway input. Thus, we found convergence of both projection systems on single CA1 pyramidal and interneurons with dendrites that access the layers where perforant pathway fibers and Schaffer collaterals end.

  12. Aspiration of Nasopore nasal packing.

    PubMed

    Smith, Jonathan; Reddy, Ekambar

    2017-10-04

    We present a case of postoperative Nasopore aspiration in an otherwise fit and well 11-year-old. An endoscopic adenoidectomy had been performed without incident and Nasopore packing placed into each nasal cavity. Immediately after extubation, there was marked hypoxia, tachypnoea and high clinical suspicion of pack aspiration. The patient returned to theatre for emergency rigid bronchoscopy and retrieval of nasal packing. © BMJ Publishing Group Ltd (unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  13. Electrophysiological and morphological properties of neurons in layer 5 of the rat postrhinal cortex.

    PubMed

    Sills, Joseph B; Connors, Barry W; Burwell, Rebecca D

    2012-09-01

    The postrhinal (POR) cortex of the rat is homologous to the parahippocampal cortex of the primate based on connections and other criteria. POR provides the major visual and visuospatial input to the hippocampal formation, both directly to CA1 and indirectly through connections with the medial entorhinal cortex. Although the cortical and hippocampal connections of the POR cortex are well described, the physiology of POR neurons has not been studied. Here, we examined the electrical and morphological characteristics of layer 5 neurons from POR cortex of 14- to 16-day-old rats using an in vitro slice preparation. Neurons were subjectively classified as regular-spiking (RS), fast-spiking (FS), or low-threshold spiking (LTS) based on their electrophysiological properties and similarities with neurons in other regions of neocortex. Cells stained with biocytin included pyramidal cells and interneurons with bitufted or multipolar dendritic patterns. Similarity analysis using only physiological data yielded three clusters that corresponded to FS, LTS, and RS classes. The cluster corresponding to the FS class was composed entirely of multipolar nonpyramidal cells, and the cluster corresponding to the RS class was composed entirely of pyramidal cells. The third cluster, corresponding to the LTS class, was heterogeneous and included both multipolar and bitufted dendritic arbors as well as one pyramidal cell. We did not observe any intrinsically bursting pyramidal cells, which is similar to entorhinal cortex but unlike perirhinal cortex. We conclude that POR includes at least two major classes of neocortical inhibitory interneurons, but has a functionally restricted cohort of pyramidal cells.

  14. Age-related Changes in Lateral Entorhinal and CA3 Neuron Allocation Predict Poor Performance on Object Discrimination

    PubMed Central

    Maurer, Andrew P.; Johnson, Sarah A.; Hernandez, Abbi R.; Reasor, Jordan; Cossio, Daniela M.; Fertal, Kaeli E.; Mizell, Jack M.; Lubke, Katelyn N.; Clark, Benjamin J.; Burke, Sara N.

    2017-01-01

    Age-related memory deficits correlate with dysfunction in the CA3 subregion of the hippocampus, which includes both hyperactivity and overly rigid activity patterns. While changes in intrinsic membrane currents and interneuron alterations are involved in this process, it is not known whether alterations in afferent input to CA3 also contribute. Neurons in layer II of the lateral entorhinal cortex (LEC) project directly to CA3 through the perforant path, but no data are available regarding the effects of advanced age on LEC activity and whether these activity patterns update in response to environmental change. Furthermore, it is not known the extent to which age-related deficits in sensory discrimination relate to the inability of aged CA3 neurons to update in response to new environments. Young and aged rats were pre-characterized on a LEGO© object discrimination task, comparable to behavioral tests in humans in which CA3 hyperactivity has been linked to impairments. The cellular compartment analysis of temporal activity with fluorescence in situ hybridization for the immediate-early gene Arc was then used to identify the principal cell populations that were active during two distinct epochs of random foraging in different environments. This approach enabled the extent to which rats could discriminate two similar objects to be related to the ability of CA3 neurons to update across different environments. In both young and aged rats, there were animals that performed poorly on the LEGO object discrimination task. In the aged rats only, however, the poor performers had a higher percent of CA3 neurons that were active during random foraging in a novel environment, but this is not related to the ability of CA3 neurons to remap when the environment changed. Afferent neurons to CA3 in LEC, as identified with the retrograde tracer choleratoxin B (CTB), also showed a higher percentage of cells that were positive for Arc mRNA in aged poor performing rats. This suggests

  15. Selective Degeneration of Entorhinal-CA1 Synapses in Alzheimer's Disease via Activation of DAPK1

    PubMed Central

    Shu, Shu; Zhu, Houze; Tang, Na; Chen, Wenting; Li, Xinyan; Li, Hao; Pei, Lei; Liu, Dan; Mu, Yangling; Tian, Qing

    2016-01-01

    Excitatory pyramidal neurons in the entorhinal cortical layer II region (ECIIPN) form functional excitatory synapses with CA1 parvalbumin inhibitory neurons (CA1PV) and undergo selective degeneration in the early stages of Alzheimer's disease (AD). Here, we show that death-associated protein kinase 1 (DAPK1) is selectively activated in ECIIPN of AD mice. Inhibition of DAPK1 by deleting a catalytic domain or a death domain of DAPK1 rescues the ECIIPN-CA1PV synaptic loss and improves spatial learning and memory in AD mice. This study demonstrates that activation of DAPK1 in ECIIPN contributes to a memory loss in AD and hence warrants a promising target for the treatment of AD. SIGNIFICANCE STATEMENT Our recent study reported that excitatory pyramidal neurons in the entorhinal cortical layer II region (ECIIPN) target to CA1 parvalbumin-type inhibitory neurons (CA1PV) at a direct pathway and are one of the most vulnerable brain cells that are selectively degenerated in the early stage of Alzheimer's disease (AD). Our present study shows that death-associated protein kinase 1 (DAPK1) is selectively activated in ECIIPN of AD mice. Inhibition of DAPK1 by deleting a catalytic domain or a death domain of DAPK1 rescues the ECIIPN-CA1PV synaptic loss and improves spatial learning and memory in the early stage of AD. These data not only demonstrate a crucial molecular event for synaptic degeneration but also provide a therapeutic target for the treatment of AD. PMID:27798139

  16. A Goal Direction Signal in the Human Entorhinal/Subicular Region

    PubMed Central

    Chadwick, Martin J.; Jolly, Amy E.J.; Amos, Doran P.; Hassabis, Demis; Spiers, Hugo J.

    2015-01-01

    Summary Navigating to a safe place, such as a home or nest, is a fundamental behavior for all complex animals. Determining the direction to such goals is a crucial first step in navigation. Surprisingly, little is known about how or where in the brain this “goal direction signal” is represented. In mammals, “head-direction cells” are thought to support this process, but despite 30 years of research, no evidence for a goal direction representation has been reported [1, 2]. Here, we used fMRI to record neural activity while participants made goal direction judgments based on a previously learned virtual environment. We applied multivoxel pattern analysis [3–5] to these data and found that the human entorhinal/subicular region contains a neural representation of intended goal direction. Furthermore, the neural pattern expressed for a given goal direction matched the pattern expressed when simply facing that same direction. This suggests the existence of a shared neural representation of both goal and facing direction. We argue that this reflects a mechanism based on head-direction populations that simulate future goal directions during route planning [6]. Our data further revealed that the strength of direction information predicts performance. Finally, we found a dissociation between this geocentric information in the entorhinal/subicular region and egocentric direction information in the precuneus. PMID:25532898

  17. A Vacuum-Aspirator for Counting Termites

    Treesearch

    Susan C. Jones; Joe K. Mauldin

    1983-01-01

    An aspirator-system powered by a vacuum cleaner is described for manually counting termites. It is significantly faster and termite survival is at least as high as when using a mouth-aspirator for counting large numbers of termites.

  18. Lifelong Learning: Capabilities and Aspirations

    ERIC Educational Resources Information Center

    Ilieva-Trichkova, Petya

    2016-01-01

    The present paper discusses the potential of the capability approach in conceptualizing and understanding lifelong learning as an agency process, and explores its capacity to guide empirical studies on lifelong learning. It uses data for 20 countries from the Adult Education Survey (2007; 2011) and focuses on aspirations for lifelong learning. The…

  19. Liposuction: more curettage than aspiration.

    PubMed

    Mottura, A A

    1991-01-01

    After infiltration with epinephrine solution in each adipose area, an 8- or 10-mm cannula, without the suction tube connected, was introduced. With a curettage maneuver and by directing the cannula upward, the fat began to come out spontaneously. After obtaining a considerable amount of fat, the suction tube was connected and the remaining fat tissue aspirated at low suction power (250 mm Hg). With this curettage maneuver adiposity of the abdomen, knees, and trochanteric areas can be reduced. However, in the back, buttocks, or thighs, where adiposity is more fibrous, aspiration is needed from the start in almost every case, but always at low-power suction. This procedure is indicated in particular for the face and neck and for secondary liposuction. The fact that fat comes out easily through the cannula (without suction) demonstrates that the curettage maneuver is more important than the aspiration. Only with curettage can a considerable amount of fat be removed. No fat is removed when aspiration of 1 atm without a curettage maneuver is used. Suction only helps to remove fat already mobilized and free in the cannula. Our experience includes 34 patients.

  20. Dermabrasion using an ultrasonic surgical aspirator.

    PubMed

    Ito, Y; Kondo, S; Sumiya, N; Yoshii, M; Otani, K; Wako, M

    1996-04-01

    We used an ultrasonic surgical aspirator on the epidermal surface to perform dermabrasion instead of the conventional motor-driven grinder. It was determined on histologic examination that it is possible to fragment the epidermis with greater selectively using the ultrasonic surgical aspirator. Abrasion also can be performed safely on spotty lesions and intricate, problematic regions with the ultrasonic surgical aspirator. We feel that the ultrasonic surgical aspirator is a promising device for use in dermabrasion.

  1. Aspirations of Latina Adolescent Suicide Attempters

    ERIC Educational Resources Information Center

    Hausmann-Stabile, Carolina; Gulbas, Lauren; Zayas, Luis H.

    2013-01-01

    Parents' aspirations and expectations are communicated to their offspring. Children internalize their parents' aspirations and accept some of the expectations while rejecting others, all part of the developmental process and identity-consolidation. When the aspirations and expectations of youth and parents are incongruent, the outcomes…

  2. Applying a Typology to Vocational Aspirations.

    ERIC Educational Resources Information Center

    Holland, John L.; Gottfredson, Gary D.

    The psychological meaning and predictive value of a person's vocational aspirations were examined by applying Holland's typology to the vocational aspirations of high school juniors (N=1,005), college juniors (N=692), employed adults (N=140), and a second sample of college students studied over a 1 year interval (N=624). The aspirational data were…

  3. Crowning achievement: a case of dental aspiration.

    PubMed

    Mark, Nicholas M; Lessing, Juan N; Çoruh, Başak

    2015-12-01

    Aspiration of foreign bodies during dental procedures is a rare but potentially serious complication. We present a case of a 75-year-old man who aspirated a dental crown requiring flexible bronchoscopic retrieval. We discuss the risk factors for aspiration, the radiographic features of diagnosis, and the techniques for management and retrieval.

  4. Crowning achievement: a case of dental aspiration

    PubMed Central

    Mark, Nicholas M.; Lessing, Juan N.; Çoruh, Başak

    2015-01-01

    Aspiration of foreign bodies during dental procedures is a rare but potentially serious complication. We present a case of a 75-year-old man who aspirated a dental crown requiring flexible bronchoscopic retrieval. We discuss the risk factors for aspiration, the radiographic features of diagnosis, and the techniques for management and retrieval. PMID:26649115

  5. Aspirations of Latina Adolescent Suicide Attempters

    ERIC Educational Resources Information Center

    Hausmann-Stabile, Carolina; Gulbas, Lauren; Zayas, Luis H.

    2013-01-01

    Parents' aspirations and expectations are communicated to their offspring. Children internalize their parents' aspirations and accept some of the expectations while rejecting others, all part of the developmental process and identity-consolidation. When the aspirations and expectations of youth and parents are incongruent, the outcomes…

  6. Raising the Career Aspirations of Gifted Girls.

    ERIC Educational Resources Information Center

    Kerr, Barbara A.

    1983-01-01

    Tested the effectiveness of a one-day career guidance laboratory on the career aspirations of 48 gifted male and female high school students. Results showed the program was effective for the girls, who raised their career aspirations significantly while the boys, who began with higher aspirations, did not change. (JAC)

  7. Silent aspiration: what do we know?

    PubMed

    Ramsey, Deborah; Smithard, David; Kalra, Lalit

    2005-01-01

    Although clinically evident aspiration is common in subjects with dysphagia, a significant proportion may aspirate silently, i.e., without any outward signs of swallowing difficulty. This article reviews the literature on the prevalence, etiology, and prognostic significance of silent aspiration. An electronic database search was performed using silent aspiration, aspiration, dysphagia, and stroke as search terms, together with hand-searching of articles. Silent aspiration has been described in many conditions and subgroups of patients (including normal individuals), using a number of detection methods, making comparisons a challenge. The best data are for acute stroke, in which 2%-25% of patients may aspirate silently. Mechanisms associated with silent aspiration may include central or local weakness/incoordination of the pharyngeal musculature, reduced laryngopharyngeal sensation, impaired ability to produce a reflexive cough, and low substance P or dopamine levels. In terms of prognosis, silent aspiration has been associated with increased morbidity and mortality in many but not all studies. However, some degree of silent aspiration at night may be normal in healthy individuals. The phenomenon of silent aspiration is poorly understood and further research is needed to improve methods of detection and thereby better define its prevalence and prognostic significance.

  8. Aspirations of Latina adolescent suicide attempters

    PubMed Central

    Hausmann-Stabile, Carolina; Gulbas, Lauren; Zayas, Luis H.

    2013-01-01

    Parents’ aspirations and expectations are communicated to their offspring. Children internalize their parents’ aspirations and accept some of the expectations while rejecting others, all part of the developmental process and identity-consolidation. When the aspirations and expectations of youth and parents are incongruent, the outcomes in youths’ behavior can be deleterious, such as when adolescents manifest suicidal behaviors. We examined aspirations expressed by 12 Latina adolescent suicide attempters and their parents and compared them to 12 non-suicidal Latinas and parents. Qualitative analyses revealed that incongruence of aspirations between girls and their parents were greater among suicidal teens. Suicidal and non-suicidal Latinas presented contrasting aspirations: the former on gaining independence and the latter on completing their education and pursuing careers. Findings may inform developmental research and ways in which clinicians and policymakers can help Latinas achieve their own and their parents’ aspirations. PMID:24013464

  9. [Pathophysiology and Therapeutic Approach of Pulmonary Aspiration].

    PubMed

    Uchida, Kanji

    2016-01-01

    Pulmonary aspiration is one of the serious adverse events in general anesthesia. Aspiration induced lung injury varies according to the nature of the contents of aspirates (acid or small particles in gastrointestinal tract, bile acid), amount of aspirates, and host-defense status. Early inflammatory responses to acid and small particles from gastrointestinal contents are categorized as aspiration pneumonitis causing rapid respiratory deterioration with early restoration of lung injury within a couple of days. Late phase lung injury is usually "aspiration pneumonia" caused by bacteria colonized in the aspirates. Treatment mainstream is to support respiratory function until the lung resolves from injury. Extracorporeal membrane oxygenation is another promising therapeutic option for cases with severe lung damage to keep the "lung rest" during fulminant lung injury, avoiding further lung damage by injurious ventilation. Empirical administration of antibiotics covering wide spectrum followed by meticulous bacteriological studies to either de-escalate or discontinue antibiotics is crucial.

  10. Aspiration of a speaking valve

    PubMed Central

    Schembri, John; Cortis, Kelvin; Mallia Azzopardi, Charles; Montefort, Stephen

    2013-01-01

    Foreign body aspiration (FBA) is a relatively common and serious condition that can result in a spectrum of presentations ranging from incidental to acutely life-threatening. Described here is a case of aspiration of a tracheo-oesophageal speaking valve through a permanent tracheostomy that went unnoticed for a number of years, and an overview of the technique used for its removal. A 70-year-old ex-heavy smoker with a permanent tracheo-oesophageal fistula presented with a relatively recent history of increasing shortness of breath, sputum purulence and haemoptysis. Further investigation with a CT scan and bronchoscopy revealed the presence of a foreign body within his right lower lobe bronchus which was later removed by advancing a flexible bronchoscope over a rigid one. PMID:23861275

  11. SUBCORTICAL CONNECTIONS OF THE PERIRHINAL, POSTRHINAL, AND ENTORHINAL CORTICES OF THE RAT. I. AFFERENTS

    PubMed Central

    Pereira, Inês Tomás; Agster, Kara L.; Burwell, Rebecca D.

    2016-01-01

    In this study we characterized the subcortical afferents for the rat PER areas 35 and 36, POR, and the lateral and medial entorhinal areas (LEA and MEA). We analyzed 33 retrograde tract-tracing experiments distributed across the five regions. For each experiment, we estimated the total numbers, percentages, and densities of labeled cells in 36 subcortical structures and nuclei distributed across septum, basal ganglia, claustrum, amygdala, olfactory structures, thalamus, and hypothalamus. We found that the complement of subcortical inputs differs across the five regions, especially the PER and POR. The PER receives input from the reuniens, suprageniculate, and medial geniculate thalamic nuclei as well as the amygdala. Overall, the subcortical inputs to the PER are consistent with a role in perception, multimodal processing, and the formation of associations that include the motivational significance of individual items and objects. Subcortical inputs to the POR were dominated by the dorsal thalamus, particularly the lateral posterior nucleus, a region implicated in visuospatial attention. The complement of subcortical inputs to the POR is consistent with a role in representing and monitoring the local spatial context. We also report that, in addition to the PER, the LEA and the medial band of the MEA also receive strong amygdala input. In contrast, subcortical input to the POR and the MEA lateral band includes much less amygdala input and is dominated by dorsal thalamic nuclei, particularly nuclei involved in spatial information processing. Like the cortical inputs, the patterns of subcortical inputs to these regions are consistent both with the view that the dorsal hippocampus is important for spatial cognition and the ventral hippocampus is important for affective cognition, and the view that they provide considerable functional integration. We conclude that the patterns of subcortical inputs to the PER, POR, and the entorhinal LEA and MEA provide further evidence

  12. Temporal Cortex Morphology in Mesial Temporal Lobe Epilepsy Patients and Their Asymptomatic Siblings.

    PubMed

    Alhusaini, Saud; Whelan, Christopher D; Doherty, Colin P; Delanty, Norman; Fitzsimons, Mary; Cavalleri, Gianpiero L

    2016-03-01

    Temporal cortex abnormalities are common in patients with mesial temporal lobe epilepsy due to hippocampal sclerosis (MTLE+HS) and believed to be relevant to the underlying mechanisms. In the present study, we set out to determine the familiarity of temporal cortex morphologic alterations in a cohort of MTLE+HS patients and their asymptomatic siblings. A surface-based morphometry (SBM) method was applied to process MRI data acquired from 140 individuals (50 patients with unilateral MTLE+HS, 50 asymptomatic siblings of patients, and 40 healthy controls). Using a region-of-interest approach, alterations in temporal cortex morphology were determined in patients and their asymptomatic siblings by comparing with the controls. Alterations in temporal cortex morphology were identified in MTLE+HS patients ipsilaterally within the anterio-medial regions, including the entorhinal cortex, parahippocampal gyrus, and temporal pole. Subtle but similar pattern of morphology changes with a medium effect size were also noted in the asymptomatic siblings. These localized alterations were related to volume loss that appeared driven by shared contractions in cerebral cortex surface area. These findings indicate that temporal cortex morphologic alterations are common to patients and their asymptomatic siblings and suggest that such localized traits are possibly heritable. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  13. Ingested and Aspirated Foreign Bodies.

    PubMed

    Green, S Sarah

    2015-10-01

    Esophageal and aspirated foreign bodies have important clinical significance, and both should be considered carefully when the history or physical examination findings raise sufficient suspicion. The published evidence regarding the diagnosis and management of foreign body ingestion or aspiration is weighted disproportionately with observational studies, case controls, expert opinion, and systematic reviews. Most of the publications would receive a categorization of C (observational studies including case-control and cohort design) and D (expert opinion, case reports, and clinical reasoning). One of the few prospective studies examining the diagnostic evaluation of foreign body aspiration in children could be considered level B evidence (randomized clinical trials, systematic reviews, or diagnostic studies with minor limitations). This study found that the medical history is the most important predictive part of the evaluation. There is evidence for considering bronchoscopy if there is significant history suggestive of foreign body aspiration, even in the setting of normal physical examination findings. (28). Most ingested foreign bodies spontaneously pass without incident. However, special attention should be paid to objects in the esophagus as well as to batteries and magnets. Based on a systematic review of the literature (level B evidence) and the potential for rapid and life-threatening damage, batteries in the esophagus should be removed immediately. (10) Other objects, such as coins, may be observed for passage in an asymptomatic patient. In addition, given the high risk of significant complications, ingestion of high-powered magnets should be quickly and carefully evaluated. Although single magnets are likely to pass without complication, multiple magnets or magnets ingested with other metal objects can cause significant damage and should be removed if there is any concern for mural entrapment, bowel perforation, or failure to progress. (10

  14. Lack of effect of entorhinal kindling on L-(/sup 3/H)glutamic acid presynaptic uptake and postsynaptic binding in hippocampus

    SciTech Connect

    Slevin, J.T.; Ferrara, L.P.

    1985-07-01

    Sodium-independent L-(/sup 3/H)glutamic acid binding and sodium-dependent L-(/sup 3/H)glutamic acid high affinity uptake were measured in hippocampal membranes of rats administered electroshock seizures or kindled to class 5 seizures by entorhinal cortical stimulation. There were no differences in these glutamatergic synaptic markers among electroshocked, kindled, or surgical control animals. Entorhinal kindling is not a reflection of activity-regulated facilitation of perforant path glutamatergic neurotransmission.

  15. Tracheobronchial Foreign Body Aspiration: Dental Prosthesis

    PubMed Central

    Köse, Ataman; Kostak, Dilek; Aramagan, Erol; Durak, Aslıhan; Seçkin, Nur Sezin; Dönmez, Serdar Süha; Melek, Hüseyin

    2014-01-01

    It is important to extract foreign bodies for avoiding life-threatening complications. They can lead to death if they are not treated. Different signs and symptoms could occur according to the complete or partial airway obstruction. Foreign body aspiration is a rare incident in adults. The organic foreign materials such as foods are found to be aspirated more commonly and are usually settled in the right bronchial system. However, dental prosthesis and teeth aspirations are rare in literature. In our study, a 52-year-old male patient who had aspirated the front part of his lower dental prosthesis accidentally is presented and the foreign body is extracted by using rigid bronchoscopy. There are many causes of aspiration but dental prosthetic aspirations should be kept in mind during sleep. For this reason, dental apparatus must be taken out while asleep. PMID:25165606

  16. Strategies for prophylaxis and treatment for aspiration.

    PubMed

    Kalinowski, Christopher Peter Henry; Kirsch, Jeffery Robert

    2004-12-01

    The absolute incidence of aspiration is difficult to define because of its relatively low occurrence and difficulty in diagnosis. The gastric volume predisposing to aspiration is larger than 30 ml. Fasting times for fluids have reduced; however, a large meal may require 9 hours of preoperative fasting. Preoperative carbohydrate-enriched beverages may attenuate postoperative catabolism. Aspiration occurs most frequently during induction and laryngoscopy. Awake fibre-optic intubation may be a suitable alternative in high-risk cases for aspiration. The role of cricoid pressure in anaesthesia needs re-evaluation as radiological and clinical evidence suggest that it may be ineffective and may impede intubation and ventilation. Chemoprophylaxis does not reduce the severity of aspiration pneumonitis as gastric bile is unaffected by these agents and induces a worse pneumonitis than gastric acid. Patients may be discharged home 2 hours after aspirating provided they are clinically unaffected and have postoperative surveillance.

  17. Aspiration thrombectomy in concert with stent thrombectomy.

    PubMed

    Dumont, Travis M; Mokin, Maxim; Sorkin, Grant C; Levy, Elad I; Siddiqui, Adnan H

    2013-07-12

    In the SWIFT and TREVO 2 trials, aspiration thrombectomy was not able to be performed. Outside these studies, in post-market application, the interventionist can use aspiration thrombectomy in addition to stent device thrombectomy. This technique is described in detail in the present report. Combined aspiration/stentriever thrombectomy may improve recanalization efforts, simplify a second thrombectomy attempt if necessary and may limit distal embolization.

  18. Aspiration

    MedlinePlus

    ... diagnosis of benign lesions. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine . 24th ed. Philadelphia, PA: ... patient with liver disease. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine . 24th ed. Philadelphia, PA: ...

  19. Effect of aging on cough and swallowing reflexes: implications for preventing aspiration pneumonia.

    PubMed

    Ebihara, Satoru; Ebihara, Takae; Kohzuki, Masahiro

    2012-02-01

    The impairment of airway protective reflexes, i.e., swallowing and cough reflexes, is thought to be one of the major causes for aspiration pneumonia in older people. Restoration of cough and swallowing reflexes in the elderly is key to preventing aspiration pneumonia in the elderly. Although, the medical literature has asserted that cough and swallowing are controlled primarily by the brainstem, recent advances in human brain imaging has provided evidence that cortical and subcortical structures play critical roles in cough and swallowing control. Because of their nature, reflexive cough and swallowing activate both sensory and motor areas in the cortex. In both protective reflexes, the sensory component, including sensory cortex in reflexive circuits, seems to be more vulnerable to aging than the motor component, including the motor cortex. Therefore, the strategy to restore cough and swallowing reflexes should be focused on compensations of sensory components in these reflexive circuits. Remedies to enhance sensory nerve terminals and sensory cortical areas related to these reflexes might be useful to prevent aspiration pneumonia in the elderly.

  20. ASPIRE - the first British student rocket programme

    NASA Astrophysics Data System (ADS)

    Baker, Adam M.; Murray, J.; Osborne, R.; Macfarlane, J.

    ASPIRE is the first British programme aiming to create and develop a small scale, hybrid engine powered launch vehicle. The project is also unique because it is a wholly amateur effort, volunteer team members having little or no professional experience in launch vehicle design, manufacture and operations; and being a mix of students and young professionals. Participants have the opportunity to develop their experience in the engineering/scientific, operational and management areas which ASPIRE encompasses. This experience will then be validated through the launching of a series of test vehicles, culminating in a demonstration of the orbital insertion of a payload by the year 2000. ASPIRE aims to eventually return an independent orbital launch capability to Britain, for the first time since 1971. This paper outlines the technical details of the ASPIRE rockets, including: airframe design and manufacture, hybrid motor design and testing, avionics development, guidance and recovery techniques, range safety practise and marketing and fund-raising. It will also cover the organisation and ethos of the programme in general. A timeline for the ASPIRE programme will be detailed, from the original ASPIRE 1 construction and launch in 1991/1992, evolving through the current series of ASPIRE Development Vehicles (ADVs), to ASPIRE 2 and 3, where the hybrid motor and other engineering subsystems are to be integrated on an increasing scale. The proposed union of an ASPIRE 3 vehicle with an Australian AUSROC launcher to achieve the 2000 orbital goal will also be covered.

  1. Thrombus aspiration catheter is a Dottering balloon.

    PubMed

    Sheshagiri Rao, D; Barik, Ramachandra; Prasad, Akula Siva

    2016-01-01

    Coronary angiogram in a young man with history of STEMI with delayed presentation revealed subtotal occlusion of left anterior descending artery (LAD) with large thrombotic filling defect distal to the critical lesion. PCI was preferred without delay because of ongoing chest pain. Several runs of thrombus aspiration failed to detect any visible thrombus. However, the immediate angiogram after thrombus aspiration showed complete distal embolization of the thrombus which could have been achieved by Dottering or balloon dilatation. In contrary to the general perception, does thrombus aspiration push more thrombus than it can aspirate?

  2. High Aspirations but Low Progression: The Science Aspirations-Careers Paradox amongst Minority Ethnic Students

    ERIC Educational Resources Information Center

    DeWitt, Jennifer; Archer, Louise; Osborne, Jonathan; Dillon, Justin; Willis, Beatrice; Wong, Billy

    2011-01-01

    Students' interest in studying science and their aspirations to pursue science-related careers is a topic of global concern. In this paper, a set of data gathered for the initial phase of the 5-year study of Science Aspirations and Careers: Age 10-14 (the ASPIRES project) is presented. In the initial phase of this project, a questionnaire…

  3. Entorhinal denervation induces homeostatic synaptic scaling of excitatory postsynapses of dentate granule cells in mouse organotypic slice cultures.

    PubMed

    Vlachos, Andreas; Becker, Denise; Jedlicka, Peter; Winkels, Raphael; Roeper, Jochen; Deller, Thomas

    2012-01-01

    Denervation-induced changes in excitatory synaptic strength were studied following entorhinal deafferentation of hippocampal granule cells in mature (≥ 3 weeks old) mouse organotypic entorhino-hippocampal slice cultures. Whole-cell patch-clamp recordings revealed an increase in excitatory synaptic strength in response to denervation during the first week after denervation. By the end of the second week synaptic strength had returned to baseline. Because these adaptations occurred in response to the loss of excitatory afferents, they appeared to be in line with a homeostatic adjustment of excitatory synaptic strength. To test whether denervation-induced changes in synaptic strength exploit similar mechanisms as homeostatic synaptic scaling following pharmacological activity blockade, we treated denervated cultures at 2 days post lesion for 2 days with tetrodotoxin. In these cultures, the effects of denervation and activity blockade were not additive, suggesting that similar mechanisms are involved. Finally, we investigated whether entorhinal denervation, which removes afferents from the distal dendrites of granule cells while leaving the associational afferents to the proximal dendrites of granule cells intact, results in a global or a local up-scaling of granule cell synapses. By using computational modeling and local electrical stimulations in Strontium (Sr(2+))-containing bath solution, we found evidence for a lamina-specific increase in excitatory synaptic strength in the denervated outer molecular layer at 3-4 days post lesion. Taken together, our data show that entorhinal denervation results in homeostatic functional changes of excitatory postsynapses of denervated dentate granule cells in vitro.

  4. Properties of doublecortin-(DCX)-expressing cells in the piriform cortex compared to the neurogenic dentate gyrus of adult mice.

    PubMed

    Klempin, Friederike; Kronenberg, Golo; Cheung, Giselle; Kettenmann, Helmut; Kempermann, Gerd

    2011-01-01

    The piriform cortex receives input from the olfactory bulb and (via the entorhinal cortex) sends efferents to the hippocampus, thereby connecting the two canonical neurogenic regions of the adult rodent brain. Doublecortin (DCX) is a cytoskeleton-associated protein that is expressed transiently in the course of adult neurogenesis. Interestingly, the adult piriform cortex, which is usually considered non-neurogenic (even though some reports exist that state otherwise), also contains an abundant population of DCX-positive cells. We asked how similar these cells would be to DCX-positive cells in the course of adult hippocampal neurogenesis. Using BAC-generated transgenic mice that express GFP under the DCX promoter, we studied DCX-expression and electrophysiological properties of DCX-positive cells in the mouse piriform cortex in comparison with the dentate gyrus. While one class of cells in the piriform cortex indeed showed features similar to newly generated immature granule neurons, the majority of DCX cells in the piriform cortex was mature and revealed large Na+ currents and multiple action potentials. Furthermore, when proliferative activity was assessed, we found that all DCX-expressing cells in the piriform cortex were strictly postmitotic, suggesting that no DCX-positive "neuroblasts" exist here as they do in the dentate gyrus. We conclude that DCX in the piriform cortex marks a unique population of postmitotic neurons with a subpopulation that retains immature characteristics associated with synaptic plasticity. DCX is thus, per se, no marker of neurogenesis but might be associated more broadly with plasticity.

  5. Assessment of an Aspiring Leaders Development Program.

    ERIC Educational Resources Information Center

    Alao, Solomon; Wright, Henrietta; Newton, Vera

    This paper describes a program designed to support aspiring educational leaders' leadership competence, autonomy, relatedness, and leadership motivation. It also discusses the New Interstate School Leaders Licensure Consortium (ISLLC) standards. To assess the extent to which the program achieved its goals, 27 aspiring leaders, all of whom are…

  6. Endometrial aspiration cytology in gynecological disorders

    PubMed Central

    Jadhav, Meenal V.; Phatke, Anjali S.; Kadgi, Nalini Vinayak; Rane, Sharda R.; Kulkarni, Kalpana K.

    2016-01-01

    Context: Endometrial aspiration is not a popular modality for the study of the endometrium despite its simplicity and potential utility. Aim: The present study was aimed at evaluating the utility of endometrial aspiration in various gynecological disorders. Materials and Methods: In this diagnostic accuracy study, 55 prospectively registered women with various gynecological disorders were evaluated clinically and subjected to endometrial aspiration cytology and study of endometrial histology. Endometrial aspiration was performed by infant feeding tube in 10 cases and intra cath cannula in 45 cases. The slides were stained with rapid Papanicolaou (PAP) stain and Leishman stain. Results: Endometrial aspiration cytology showed 90% and 94.6% sampling adequacy with infant feeding tube and intra cath cannula, respectively. Intra cath cannula was very convenient to handle and superior to infant feeding tube in aspirating the endometrium. Of the two stains used, rapid PAP stain was less time-consuming and superior to Leishman stain in studying the nuclear details. Leishman stain was helpful in detecting cytoplasmic vacuoles of secretory endometrium. Overall diagnostic accuracy of endometrial cytology was 90.4% while that for morphological hormonal evaluation was 97.6%. It enjoyed a sensitivity of 91.66%, a specificity of 88.23%, positive predictive value of 94.28%, and negative predictive value of 83.33%. Conclusion: Intra cath cannula emerged as an inexpensive, effective, and convenient device for endometrial aspiration. Endometrial aspiration proved to be a fairly effective, simple, and informative diagnostic modality. PMID:27011435

  7. Grades, Aspirations, and Postsecondary Education Outcomes

    ERIC Educational Resources Information Center

    Christofides, Louis N.; Hoy, Michael; Milla, Joniada; Stengos, Thanasis

    2015-01-01

    In this paper, we exploit a rich longitudinal data set to explore the forces that, during high school, shape the development of aspirations to attend university and achieve academic success. We then investigate how these aspirations, along with grades and other variables, impact educational outcomes such as going to university and graduating. It…

  8. Undergraduate Women's Gender Awareness and Status Aspirations.

    ERIC Educational Resources Information Center

    Inoue, Yukiko

    A study was conducted to determine women's realization toward the quality of life, identifying their status aspirations. The study's primary purpose was to achieve a better understanding of how undergraduate women of Guam and Japan would aspire to their academic and social goals and how they would become aware of their gender equality. The…

  9. Aspirator increases relief valve poppet stroke

    NASA Technical Reports Server (NTRS)

    Biddle, M. E.

    1967-01-01

    Addition of an aspirator to a relief valve increases the valve poppet stroke under dynamic flow conditions. The aspirator allows poppet inlet dynamic forces to overcome relief valve spring force. It reduces the fluid pressure in the skirt cavity by providing a low pressure sense probe.

  10. Educational Aspirations in Inner City Schools

    ERIC Educational Resources Information Center

    Strand, Steve; Winston, Joe

    2008-01-01

    This research aimed to assess the nature and level of pupils' educational aspirations and to elucidate the factors that influence these aspirations. A sample of five inner city comprehensive secondary schools were selected by their local authority because of poor pupil attendance, below-average examination results and low rates of continuing in…

  11. Gendered Trends in Student Teachers' Professional Aspirations

    ERIC Educational Resources Information Center

    Smith, Joan

    2015-01-01

    The paper reports on a small-scale, exploratory study investigating the professional aspirations of a cohort of student teachers at a UK university. Questionnaires and interviews sought insights into the students' perceptions of leadership, future aspirations and self-perceptions as potential leaders. Whilst there was commonality in male and…

  12. Ultrasound-Guided Fine Needle Aspiration Biopsy of the Thyroid

    MedlinePlus

    ... Index A-Z Ultrasound-Guided Fine Needle Aspiration Biopsy of the Thyroid An ultrasound-guided thyroid biopsy ... Thyroid? What is Ultrasound-Guided Fine Needle Aspiration Biopsy of the Thyroid? During a fine needle aspiration ...

  13. Efferent connections of the rostral portion of medial agranular cortex in rats.

    PubMed

    Reep, R L; Corwin, J V; Hashimoto, A; Watson, R T

    1987-08-01

    This study of the rostral part of medial agranular cortex (AGm) was undertaken with two principal aims in mind. First, to delineate the efferent connections of AGm and compare these with the pattern of afferents defined by us in a previous study. Second, to provide a firmer basis for anatomical and functional comparisons with cortical regions in monkeys. Autoradiographic, horseradish peroxidase, and fiber degeneration techniques were used. Rostral AGm has a variety of corticocortical connections--with lateral agranular motor cortex (AGl); visual, auditory, and somatic sensory regions; and limbic/paralimbic areas including orbital, insular, perirhinal, entorhinal, retrosplenial and presubicular fields. The projections to orbital, perirhinal and entorhinal cortices are bilateral. Thalamic projections of rostral AGm are concentrated in the ventral lateral, central lateral, paracentral, mediodorsal and ventromedial nuclei. Moderate terminal fields are consistently seen in the reticular, anteromedial, central medial, gelatinosus, parafascicular, and posterior nuclei. More caudal projections reach the central gray, superior colliculus and pontine gray. The efferents of the adjacent AGl were also examined. Although many of these overlapped those of rostral AGm, there were no efferents to visual or auditory cortex and limbic/paralimbic projections were reduced. Thalamic projections were more focused in the ventral lateral and posterior nuclei and there were no terminal fields in the central gray or superior colliculus. Based on its afferent and efferent connections, role in contralateral neglect, and the results of microstimulation studies, rostral AGm can be viewed as a multimodal association area with strong ties to the motor system. On these structural and functional grounds, rostral AGm bears certain striking resemblances to the frontal eye field, supplementary motor, and arcuate premotor areas of monkey cortex.

  14. Aspiration pneumonia in dogs: pathophysiology, prevention, and diagnosis.

    PubMed

    Schulze, Heidi M; Rahilly, Louisa J

    2012-12-01

    Aspiration pneumonia and aspiration pneumonitis are associated with significant morbidity in veterinary and human medicine. A variety of medical conditions and medications can predispose patients to aspiration, and every precaution should be taken to prevent aspiration from occurring. For dogs that aspirate oral or gastric contents and subsequently develop pneumonia, monitoring and supportive care are imperative. This article discusses the pathophysiology, prevention, and diagnosis of aspiration pneumonia.

  15. Low distribution of synaptic vesicle protein 2A and synaptotagimin-1 in the cerebral cortex and hippocampus of spontaneously epileptic rats exhibiting both tonic convulsion and absence seizure.

    PubMed

    Hanaya, R; Hosoyama, H; Sugata, S; Tokudome, M; Hirano, H; Tokimura, H; Kurisu, K; Serikawa, T; Sasa, M; Arita, K

    2012-09-27

    The spontaneously epileptic rat (SER) is a double mutant (zi/zi, tm/tm) which begins to exhibit tonic convulsions and absence seizures after 6 weeks of age, and repetitive tonic seizures over time induce sclerosis-like changes in SER hippocampus with high brain-derived neurotrophic factor (BDNF) expression. Levetiracetam, which binds to synaptic vesicle protein 2A (SV2A), inhibited both tonic convulsions and absence seizures in SERs. We studied SER brains histologically and immunohistochemically after verification by electroencephalography (EEG), as SERs exhibit seizure-related alterations in the cerebral cortex and hippocampus. SERs did not show interictal abnormal spikes and slow waves typical of focal epilepsy or symptomatic generalized epilepsy. The difference in neuronal density of the cerebral cortex was insignificant between SER and Wistar rats, and apoptotic neurons did not appear in SERs. BDNF distributions portrayed higher values in the entorhinal and piriform cortices which would relate with hippocampal sclerosis-like changes. Similar synaptophysin expression in the cerebral cortex and hippocampus was found in both animals. Low and diffuse SV2A distribution portrayed in the cerebral cortex and hippocampus of SERs was significantly less than that of all cerebral lobes and inner molecular layer (IML) of the dentate gyrus (DG) of Wistar rats. The extent of low SV2A expression/distribution in SERs was particularly remarkable in the frontal (51% of control) and entorhinal cortices (47%). Lower synaptotagmin-1 expression (vs Wistar rats) was located in the frontal (31%), piriform (13%) and entorhinal (39%) cortices, and IML of the DG (38%) in SER. Focal low distribution of synaptotagmin-1 accompanying low SV2A expression may contribute to epileptogenesis and seizure propagation in SER.

  16. Surgical jejunostomy in aspiration risk patients.

    PubMed Central

    Weltz, C R; Morris, J B; Mullen, J L

    1992-01-01

    One hundred patients underwent laparotomy for independent jejunal feeding tube placement. Neurologic disease was present in 50%, and obtundation (28) and oropharyngeal dysmotility (25) were the most common indications for enteral feeding. The post-pyloric route was chosen because of aspiration risk in almost all (94%) patients. Postoperative (30-day) mortality rate was 21%, because of cardiopulmonary failure in most (18). One death resulted directly from aspiration of tube feeds. Two surgical complications required reoperation: one wound dehiscence and one small bowel obstruction. Four wound infections occurred. Two patients underwent reoperation after tube removal, and four tubes required fluoroscopically guided reinsertion for peritubular drainage (2), removal (1), and occlusion (1). Aspiration pneumonia was present in 18 patients preoperatively and in eight postoperatively. None of the patients with feeding-related preoperative aspiration pneumonia (13) had a recurrence while fed by jejunostomy. Three patients developed postoperative aspiration pneumonia before initiation of jejunostomy feedings. Jejunostomy may be performed with low morbidity rate and substantial reduction of feeding-related aspiration pneumonia, and is the feeding route of choice in aspiration risk patients. PMID:1546899

  17. Clinical profile of children with kerosene aspiration.

    PubMed

    Venkatesh, C; Sriram, P; Adhisivam, B; Mahadevan, S

    2011-07-01

    Accidental aspiration of kerosene is a common problem among children in developing countries. This descriptive study involved the retrospective analysis of children admitted with kerosene aspiration in a tertiary care hospital in South India for a year. Kerosene aspiration contributed to 60.4% of poisoning cases. Boys aged less than three years and from a rural background formed a significant proportion. Tachypnoea, cough and crepitations were the predominant clinical findings. Male gender and malnutrition (weight for age <80%) were significantly associated with prolonged hospital stay.

  18. Coronary air embolism treated with aspiration catheter

    PubMed Central

    Patterson, M S; Kiemeneij, F

    2005-01-01

    Coronary air embolism remains a recognised complication of coronary catheterisation despite a strong emphasis on prevention. Current treatment consists of supportive measures with 100% oxygen and analgesia. Recent case reports describe the use of mechanical treatments aimed at dispersing or removing the air embolus with variable success. A case of coronary air embolism causing an acute coronary syndrome is described that was definitively treated with an aspiration system. The effectiveness of the aspiration system in the distal section of an obtuse marginal artery indicates that such dedicated aspiration systems may prove useful in the standard treatment of air embolism. PMID:15831621

  19. Coronary air embolism treated with aspiration catheter.

    PubMed

    Patterson, M S; Kiemeneij, F

    2005-05-01

    Coronary air embolism remains a recognised complication of coronary catheterisation despite a strong emphasis on prevention. Current treatment consists of supportive measures with 100% oxygen and analgesia. Recent case reports describe the use of mechanical treatments aimed at dispersing or removing the air embolus with variable success. A case of coronary air embolism causing an acute coronary syndrome is described that was definitively treated with an aspiration system. The effectiveness of the aspiration system in the distal section of an obtuse marginal artery indicates that such dedicated aspiration systems may prove useful in the standard treatment of air embolism.

  20. A modified-simple technique of removing the lens cortex during cataract surgery

    PubMed Central

    Han, Kyung Eun; Han, Se Hoon; Lim, Dongkwon; Shin, Min Chul

    2017-01-01

    We describe here a surgical technique of removing the remaining cortex after phacoemulsification without performing the conventional irrigation/aspiration (I/A) procedure. In this technique, the remaining cortex attached to the posterior capsule was separated and dissected into several pieces by continuous irrigation with balanced salt solution, which was supplied through a syringe attached to a bent, blunt-tip needle. Approximately, 10 s of manual irrigation separated most of the remaining cortex from the posterior capsule. Then, the capsular bag was inflated with an ophthalmic viscoelastic device (OVD), and this pushed the separated cortex toward the capsular fornix mechanically. An intraocular lens was inserted into the capsular bag, following which the remaining cortex and OVD were removed concomitantly using an automated I/A handpiece. This technique is a simple and easy maneuver to remove the cortex from all areas, including the subincisional area, and reduce the possibility of a posterior capsule tear. PMID:28300744

  1. Entorhinal theta-frequency input to the dentate gyrus trisynaptically evokes hippocampal CA1 LTP

    PubMed Central

    Stepan, Jens; Dine, Julien; Fenzl, Thomas; Polta, Stephanie A.; von Wolff, Gregor; Wotjak, Carsten T.; Eder, Matthias

    2012-01-01

    There exists substantial evidence that some forms of explicit learning in mammals require long-term potentiation (LTP) at hippocampal CA3-CA1 synapses. While CA1 LTP has been well characterized at the monosynaptic level, it still remains unclear how the afferent systems to the hippocampus can initiate formation of this neuroplastic phenomenon. Using voltage-sensitive dye imaging (VSDI) in a mouse brain slice preparation, we show that evoked entorhinal cortical (EC) theta-frequency input to the dentate gyrus highly effectively generates waves of neuronal activity which propagate through the entire trisynaptic circuit of the hippocampus (“HTC-Waves”). This flow of activity, which we also demonstrate in vivo, critically depends on frequency facilitation of mossy fiber to CA3 synaptic transmission. The HTC-Waves are rapidly boosted by the cognitive enhancer caffeine (5 μM) and the stress hormone corticosterone (100 nM). They precisely follow the rhythm of the EC input, involve high-frequency firing (>100 Hz) of CA3 pyramidal neurons, and induce NMDA receptor-dependent CA1 LTP within a few seconds. Our study provides the first experimental evidence that synchronous theta-rhythmical spiking of EC stellate cells, as occurring during EC theta oscillations, has the capacity to drive induction of CA1 LTP via the hippocampal trisynaptic pathway. Moreover, we present data pointing to a basic filter mechanism of the hippocampus regarding EC inputs and describe a methodology to reveal alterations in the “input–output relationship” of the hippocampal trisynaptic circuit. PMID:22988432

  2. Healthcare-associated Pneumonia and Aspiration Pneumonia

    PubMed Central

    Komiya, Kosaku; Ishii, Hiroshi; Kadota, Jun-ichi

    2015-01-01

    Healthcare-associated pneumonia (HCAP) is a new concept of pneumonia proposed by the American Thoracic Society/Infectious Diseases Society of America in 2005. This category is located between community-acquired pneumonia and hospital-acquired pneumonia with respect to the characteristics of the causative pathogens and mortality, and primarily targets elderly patients in healthcare facilities. Aspiration among such patients is recognized to be a primary mechanism for the development of pneumonia, particularly since the HCAP guidelines were published. However, it is difficult to manage patients with aspiration pneumonia because the definition of the condition is unclear, and the treatment is associated with ethical aspects. This review focused on the definition, prevalence and role of aspiration pneumonia as a prognostic factor in published studies of HCAP and attempted to identify problems associated with the concept of aspiration pneumonia. PMID:25657850

  3. Aspiration pneumonia in children: an iconographic essay.

    PubMed

    de Oliveira, Gabriel Antonio; Pessanha, Laís Bastos; Guerra, Luiz Felipe Alves; Martins, Diego Lima Nava; Rondina, Ronaldo Garcia; Silva, Jamine Ronacher Passos

    2015-01-01

    In most cases of aspiration pneumonia in children, the disease is specific to this age group. Clinical and radiological correlation is essential for the diagnosis. The present pictorial essay is aimed at showing typical images of the most common etiologies.

  4. Modulation of the storage of social recognition memory by neurotransmitter systems in the insular cortex.

    PubMed

    Cavalcante, Lorena E S; Zinn, Carolina G; Schmidt, Scheila D; Saenger, Bruna F; Ferreira, Flávia F; Furini, Cristiane R G; Myskiw, Jociane C; Izquierdo, Ivan

    2017-09-15

    The insular cortex (IC) receives projections from prefrontal, entorhinal and cingulate cortex, olfactory bulb and basal nuclei and has reciprocal connections with the amygdala and entorhinal cortex. These connections suggest a possible involvement in memory processes; this has been borne out by data on several behaviors. Social recognition memory (SRM) is essential to form social groups and to establish hierarchies and social and affective ties. Despite its importance, knowledge about the brain structures and the neurotransmitter mechanisms involved in its processing is still scarce. Here we study the participation of NMDA-glutamatergic, D1/D5-dopaminergic, H2-histaminergic, β-adrenergic and 5-HT1A-serotoninergic receptors of the IC in the consolidation of SRM. Male Wistar rats received intra-IC infusions of substances acting on these receptors immediately after the sample phase of a social discrimination task and 24h later were exposed to a 5-min retention test. The intra-IC infusion of antagonists of D1/D5, β-adrenergic or 5-HT1A receptors immediately after the sample phase impaired the consolidation of SRM. These effects were blocked by the concomitant intra-IC infusion of agonists of these receptors. Antagonists and agonists of NMDA and H2 receptors had no effect on SRM. The results suggest that the dopaminergic D1/D5, β-adrenergic and serotonergic 5-HT1A receptors in the IC, but not glutamatergic NMDA and the histaminergic H2 receptors, participate in the consolidation of SRM in the IC. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. A novel function for Wnt signaling modulating neuronal firing activity and the temporal structure of spontaneous oscillation in the entorhinal-hippocampal circuit.

    PubMed

    Oliva, Carolina A; Inestrosa, Nibaldo C

    2015-07-01

    During early and late postnatal developments, the establishment of functional neuronal connectivity depends on molecules like Wnt that help the recently formed synapses to establish and consolidate their new cellular interactions. However, unlike other molecules, whether Wnt can modulate the firing properties of cells is unknown. Here, for the first time we explore the physiological effect of the canonical and non-canonical Wnt pathways on a circuit that is currently generating oscillatory activity, the entorhinal cortex-hippocampal circuit. Our results indicate that Wnt pathways have strong influence in the circuital and cellular properties depending on the Wnt protein isoforms, concentration, and type of neuronal circuit. Antibodies against canonical and non-canonical ligands, as well as WASP-1 and sFRP-2, demonstrate that constitutive release of Wnts contributes to the maintenance of the network and intrinsic properties of the circuit. Furthermore, we found that the excess of Wnt3a or the permanent intracellular activation of the pathway with BIO-6 accelerates the period of the oscillation by disrupting the oscillatory units (Up states) in short units, presumably by affecting the synaptic mechanisms that couples neurons into the oscillatory cycle, but without affecting the spike generation. Instead, low doses of Wnt5a increase the period of the oscillation in EC by incorporating new cells into the network activity, probably modifying firing activity in other places of the circuit. Moreover, we found that Wnt signaling operates under different principles in the hippocampus. Using pyrvinium pamoate, a Wnt/β-catenin dependent pathway inhibitor, we demonstrated that this pathway is essential to keep the firing activity in the circuit CA3, and in less degree of CA1 circuit. However, CA1 circuit possesses homeostatic mechanisms to up-regulate the firing activity when it has been suppressed in CA3, and to down-modulate the cellular excitability when exacerbated

  6. Lithium/pilocarpine status epilepticus-induced neuropathology of piriform cortex and adjoining structures in rats is age-dependent.

    PubMed

    Druga, R; Kubová, H; Suchomelová, L; Haugvicová, R

    2003-01-01

    Distribution of LiCl/pilocarpine status epilepticus-induced neuronal damage was studied in the piriform cortex and in adjoining structures in 12-day-old, 25-day-old and adult rats. No distinct structural and neuronal alterations were detected in the basal telencephalon in 12-day-old rats surviving status epilepticus (SE) for one week or two months. In 25-day-old rats a decrease in Nissl staining was evident. There was also cell loss and gliosis in the caudal 2/3 of the piriform cortex, in the superficial amygdaloid nuclei, in the dorsal and ventral endopiriform nucleus and in the rostrolateral part of the entorhinal cortical area. In adult animals, the topography of neuropathological changes in the basal telencephalon was comparable to those in 25-day-old rats. The damage in the caudal 2/3 or caudal half of the piriform cortex in adult rats with survival times one week or two months was characterized by a marked loss of neurons and striking glial infiltration. The thickness of the piriform cortex and superficial amygdaloid nuclei was significantly reduced. In 25-day-old and in adult animals the sublayer IIb and layer III of the piriform cortex was more affected, while sublayer IIa was less damaged. Parvalbumin (PV) immunocytochemistry revealed a significant decrease in the number of PV-immunoreactive neurons in the rostral piriform cortex and in the dorsal claustrum in animals surviving for two months.

  7. Detecting and discriminating novel objects: The impact of perirhinal cortex disconnection on hippocampal activity patterns

    PubMed Central

    Amin, Eman; Olarte‐Sánchez, Cristian M.; Aggleton, John P.

    2016-01-01

    ABSTRACT Perirhinal cortex provides object‐based information and novelty/familiarity information for the hippocampus. The necessity of these inputs was tested by comparing hippocampal c‐fos expression in rats with or without perirhinal lesions. These rats either discriminated novel from familiar objects (Novel‐Familiar) or explored pairs of novel objects (Novel‐Novel). Despite impairing Novel‐Familiar discriminations, the perirhinal lesions did not affect novelty detection, as measured by overall object exploration levels (Novel‐Novel condition). The perirhinal lesions also largely spared a characteristic network of linked c‐fos expression associated with novel stimuli (entorhinal cortex→CA3→distal CA1→proximal subiculum). The findings show: I) that perirhinal lesions preserve behavioral sensitivity to novelty, whilst still impairing the spontaneous ability to discriminate novel from familiar objects, II) that the distinctive patterns of hippocampal c‐fos activity promoted by novel stimuli do not require perirhinal inputs, III) that entorhinal Fos counts (layers II and III) increase for novelty discriminations, IV) that hippocampal c‐fos networks reflect proximal‐distal connectivity differences, and V) that discriminating novelty creates different pathway interactions from merely detecting novelty, pointing to top‐down effects that help guide object selection. © 2016 The Authors Hippocampus Published by Wiley Periodicals, Inc. PMID:27398938

  8. Evaluating the Small-World-Ness of a Sampled Network: Functional Connectivity of Entorhinal-Hippocampal Circuitry

    NASA Astrophysics Data System (ADS)

    She, Qi; Chen, Guanrong; Chan, Rosa H. M.

    2016-02-01

    The amount of publicly accessible experimental data has gradually increased in recent years, which makes it possible to reconsider many longstanding questions in neuroscience. In this paper, an efficient framework is presented for reconstructing functional connectivity using experimental spike-train data. A modified generalized linear model (GLM) with L1-norm penalty was used to investigate 10 datasets. These datasets contain spike-train data collected from the entorhinal-hippocampal region in the brains of rats performing different tasks. The analysis shows that entorhinal-hippocampal network of well-trained rats demonstrated significant small-world features. It is found that the connectivity structure generated by distance-dependent models is responsible for the observed small-world features of the reconstructed networks. The models are utilized to simulate a subset of units recorded from a large biological neural network using multiple electrodes. Two metrics for quantifying the small-world-ness both suggest that the reconstructed network from the sampled nodes estimates a more prominent small-world-ness feature than that of the original unknown network when the number of recorded neurons is small. Finally, this study shows that it is feasible to adjust the estimated small-world-ness results based on the number of neurons recorded to provide a more accurate reference of the network property.

  9. Evaluating the Small-World-Ness of a Sampled Network: Functional Connectivity of Entorhinal-Hippocampal Circuitry

    PubMed Central

    She, Qi; Chen, Guanrong; Chan, Rosa H. M.

    2016-01-01

    The amount of publicly accessible experimental data has gradually increased in recent years, which makes it possible to reconsider many longstanding questions in neuroscience. In this paper, an efficient framework is presented for reconstructing functional connectivity using experimental spike-train data. A modified generalized linear model (GLM) with L1-norm penalty was used to investigate 10 datasets. These datasets contain spike-train data collected from the entorhinal-hippocampal region in the brains of rats performing different tasks. The analysis shows that entorhinal-hippocampal network of well-trained rats demonstrated significant small-world features. It is found that the connectivity structure generated by distance-dependent models is responsible for the observed small-world features of the reconstructed networks. The models are utilized to simulate a subset of units recorded from a large biological neural network using multiple electrodes. Two metrics for quantifying the small-world-ness both suggest that the reconstructed network from the sampled nodes estimates a more prominent small-world-ness feature than that of the original unknown network when the number of recorded neurons is small. Finally, this study shows that it is feasible to adjust the estimated small-world-ness results based on the number of neurons recorded to provide a more accurate reference of the network property. PMID:26902707

  10. Astrobiology explorer mission concepts (ABE/ASPIRE)

    NASA Astrophysics Data System (ADS)

    Ennico, K. A.; Sandford, S. A.; ABE/ASPIRE Science Teams

    The AstroBiology Explorer (ABE) and the Astrobiology SPace InfraRed Explorer (ASPIRE) Mission Concepts are two missions designed to address the questions (1) "Where do we come from?" and (2) "Are we alone?" as outlined in NASA's Origins Program. Both concepts use infrared spectroscopy to explore the identity, abundance, and distribution of molecules of astrobiological importance throughout the Universe. The ABE mission's observational program is focused on investigating the evolution of ice and organics in all phases of the lifecycle of carbon in the universe, from stellar birth through stellar death and exogenous delivery of these compounds to planetary systems. The ASPIRE mission's observational program expands upon ABE's core mission and also addresses the role of silicates and gas-phase materials in interstellar organic chemistry. ABE (ASPIRE) achieves these goals using a highly sensitive, cryogenically-cooled telescope in an Earth drift-away heliocentric orbit, armed with a suite of infrared spectrometers that cover the 2.5-20 (40) micron spectral region at moderate spectral resolution ( R > 2000). ASPIRE's spectrometer complement also includes a high-resolution ( R > 25,000) module over the 4-8 micron spectral region. Both missions' target lists are chosen to observe a statistically significant sample of a large number of objects of varied types in support of the tasks outlined above. The ABE and ASPIRE mission lifetimes are designed to be 14 months and 3 years, respectively, both with significant cryogen and propellant lifetime margins to support an extended observing campaign. The ABE/ASPIRE Science Operations will be carried out at NASA's Ames Research Center, and the ABE/ASPIRE database will be archived at Caltech/IPAC.

  11. To Aspire: A Systematic Reflection on Understanding Aspirations in Higher Education

    ERIC Educational Resources Information Center

    Gale, Trevor; Parker, Stephen

    2015-01-01

    Aspirations for higher education by people from low socioeconomic status backgrounds are now a focus of government policy in many OECD nations. This is part of a global trend emphasizing the perceived benefits of "raising" aspirations among under-represented groups as a social inclusion strategy to widen university participation, but…

  12. To Aspire: A Systematic Reflection on Understanding Aspirations in Higher Education

    ERIC Educational Resources Information Center

    Gale, Trevor; Parker, Stephen

    2015-01-01

    Aspirations for higher education by people from low socioeconomic status backgrounds are now a focus of government policy in many OECD nations. This is part of a global trend emphasizing the perceived benefits of "raising" aspirations among under-represented groups as a social inclusion strategy to widen university participation, but…

  13. Contributions of diverse excitatory and inhibitory neurons to recurrent network activity in cerebral cortex.

    PubMed

    Neske, Garrett T; Patrick, Saundra L; Connors, Barry W

    2015-01-21

    The recurrent synaptic architecture of neocortex allows for self-generated network activity. One form of such activity is the Up state, in which neurons transiently receive barrages of excitatory and inhibitory synaptic inputs that depolarize many neurons to spike threshold before returning to a relatively quiescent Down state. The extent to which different cell types participate in Up states is still unclear. Inhibitory interneurons have particularly diverse intrinsic properties and synaptic connections with the local network, suggesting that different interneurons might play different roles in activated network states. We have studied the firing, subthreshold behavior, and synaptic conductances of identified cell types during Up and Down states in layers 5 and 2/3 in mouse barrel cortex in vitro. We recorded from pyramidal cells and interneurons expressing parvalbumin (PV), somatostatin (SOM), vasoactive intestinal peptide (VIP), or neuropeptide Y. PV cells were the most active interneuron subtype during the Up state, yet the other subtypes also received substantial synaptic conductances and often generated spikes. In all cell types except PV cells, the beginning of the Up state was dominated by synaptic inhibition, which decreased thereafter; excitation was more persistent, suggesting that inhibition is not the dominant force in terminating Up states. Compared with barrel cortex, SOM and VIP cells were much less active in entorhinal cortex during Up states. Our results provide a measure of functional connectivity of various neuron types in barrel cortex and suggest differential roles for interneuron types in the generation and control of persistent network activity.

  14. Cerebral Cortex Regions Selectively Vulnerable to Radiation Dose-Dependent Atrophy.

    PubMed

    Seibert, Tyler M; Karunamuni, Roshan; Kaifi, Samar; Burkeen, Jeffrey; Connor, Michael; Krishnan, Anitha Priya; White, Nathan S; Farid, Nikdokht; Bartsch, Hauke; Murzin, Vyacheslav; Nguyen, Tanya T; Moiseenko, Vitali; Brewer, James B; McDonald, Carrie R; Dale, Anders M; Hattangadi-Gluth, Jona A

    2017-04-01

    Neurologic deficits after brain radiation therapy (RT) typically involve decline in higher-order cognitive functions such as attention and memory rather than sensory defects or paralysis. We sought to determine whether areas of the cortex critical to cognition are selectively vulnerable to radiation dose-dependent atrophy. We measured change in cortical thickness in 54 primary brain tumor patients who underwent fractionated, partial brain RT. The study patients underwent high-resolution, volumetric magnetic resonance imaging (T1-weighted; T2 fluid-attenuated inversion recovery, FLAIR) before RT and 1 year afterward. Semiautomated software was used to segment anatomic regions of the cerebral cortex for each patient. Cortical thickness was measured for each region before RT and 1 year afterward. Two higher-order cortical regions of interest (ROIs) were tested for association between radiation dose and cortical thinning: entorhinal (memory) and inferior parietal (attention/memory). For comparison, 2 primary cortex ROIs were also tested: pericalcarine (vision) and paracentral lobule (somatosensory/motor). Linear mixed-effects analyses were used to test all other cortical regions for significant radiation dose-dependent thickness change. Statistical significance was set at α = 0.05 using 2-tailed tests. Cortical atrophy was significantly associated with radiation dose in the entorhinal (P=.01) and inferior parietal ROIs (P=.02). By contrast, no significant radiation dose-dependent effect was found in the primary cortex ROIs (pericalcarine and paracentral lobule). In the whole-cortex analysis, 9 regions showed significant radiation dose-dependent atrophy, including areas responsible for memory, attention, and executive function (P≤.002). Areas of cerebral cortex important for higher-order cognition may be most vulnerable to radiation-related atrophy. This is consistent with clinical observations that brain radiation patients experience deficits in domains of

  15. Stability analysis of micropipette aspiration of neutrophils.

    PubMed Central

    Derganc, J; Bozic, B; Svetina, S; Zeks, B

    2000-01-01

    During micropipette aspiration, neutrophil leukocytes exhibit a liquid-drop behavior, i.e., if a neutrophil is aspirated by a pressure larger than a certain threshold pressure, it flows continuously into the pipette. The point of the largest aspiration pressure at which the neutrophil can still be held in a stable equilibrium is called the critical point of aspiration. Here, we present a theoretical analysis of the equilibrium behavior and stability of a neutrophil during micropipette aspiration with the aim to rigorously characterize the critical point. We take the energy minimization approach, in which the critical point is well defined as the point of the stability breakdown. We use the basic liquid-drop model of neutrophil rheology extended by considering also the neutrophil elastic area expansivity. Our analysis predicts that the behavior at large pipette radii or small elastic area expansivity is close to the one predicted by the basic liquid-drop model, where the critical point is attained slightly before the projection length reaches the pipette radius. The effect of elastic area expansivity is qualitatively different at smaller pipette radii, where our analysis predicts that the critical point is attained at the projection lengths that may significantly exceed the pipette radius. PMID:10866944

  16. [What is the contribution of aspiration cytology?].

    PubMed

    Pluot, M

    1999-01-01

    Aspiration cytology of thyroid nodules is essentially designed to determine the benign nature of the nodule in order to avoid purely diagnosis surgery. It is reliable in the diagnosis of anaplastic papillary and medullary carcinomas and most lymphomas, but is more problematical for the diagnosis of the benign or malignant nature of Hürthle cell tumours and certain vesicular tumours, in which cytology reveals a suspicious, doubtful or undetermined appearance. However, whether they are unambiguous or doubtful, fine needle aspiration cytology results help the surgeon to define the therapeutic strategy under the best possible conditions. A therapeutic approach is proposed, based on the formulation of aspiration cytology results into benign, malignant, suspicious and inadequate.

  17. [Patient's Risk Factors for Perioperative Aspiration Pneumonia].

    PubMed

    Ishikawa, Teruhiko; Isono, Shiroh

    2016-01-01

    This article reviews patient's own risk factors for perioperative aspiration pneumonia. Maintaining the function of the lower esophageal sphincter (LES), the airway protective reflex, and the oral hygiene are the most important to prevent the pneumonia. The LES is adversely affected by excessive stomach distention, some medication given in perioperative periods, and habitual smoking, as well as pathological status such as esophageal hiatus hernia and achalasia. Postapoplectic patients may have insufficient airway protective reflex including swallowing and laryngeal reflex. It is emphasized that the perioperative oral care is increasing in its importance for the prevention of aspiration pneumonia.

  18. Age-Group Differences in Medial Cortex Activity Associated with Thinking About Self-Relevant Agendas

    PubMed Central

    Mitchell, Karen J.; Raye, Carol L.; Ebner, Natalie C.; Tubridy, Shannon M.; Frankel, Hillary; Johnson, Marcia K.

    2009-01-01

    This functional magnetic resonance imaging (fMRI) study compared young and older adults’ brain activity as they thought about motivationally self-relevant agendas (hopes and aspirations, duties and obligations) and concrete control items (e.g., shape of USA). Young adults’ activity replicated a double dissociation (Johnson et al., 2006): an area of medial frontal gyrus/anterior cingulate cortex was most active during hopes and aspirations trials and an area of medial posterior cortex, primarily posterior cingulate, was most active during duties and obligations trials. Compared to young adults, older adults showed attenuated responses in medial cortex, especially in medial prefrontal cortex, with both less activity during self-relevant trials and less deactivation during control trials. The fMRI data, together with post-scan reports and the behavioral literature on age-group differences in motivational orientation, suggest that the differences in medial cortex seen in this study reflect young and older adults’ focus on different information during motivationally self-relevant thought. Differences also may be related to an age-associated deficit in controlled cognitive processes that are engaged by complex self-reflection and mediated by prefrontal cortex. PMID:19485660

  19. Predictors of radiolucent foreign body aspiration.

    PubMed

    Mortellaro, Vincent E; Iqbal, Corey; Fu, Roxanna; Curtis, Heather; Fike, Frankie B; St Peter, Shawn D

    2013-09-01

    Children frequently present for suspected foreign body aspiration, many have mild symptoms and/or negative radiographs raising the question of a radiolucent foreign body aspiration. Retrospective review of patients having bronchoscopy for suspected radiolucent foreign body aspiration from 2000 to 2010 collecting demographics, history, hospital presentation, radiographic, and operative details. Pearson's correlation was used between event history, presentation, radiographic details and bronchoscopically identified foreign body with P value <0.01. 138 patients, mean age 2.6 years, mean weight 15.6 kg, 68% male. Event symptoms: 81% witnessed events, 64% wheezing, 43% coughing, 39% choking, 6% stridor, and 0.7% lethargy. Hospital presentation: 70% persistent symptoms, wheezing 56%, coughing 15%, desaturations 11%, stridor 7%, choking 4%, and lethargy 1%. 92% of patients had a chest x-ray; air trapping found in 38%, and lung collapse in 21%. 2 patients received CT scans; 1 had lung collapse. Bronchoscopy identified foreign bodies in 93% of patients: food 68%, plastic 18%, non-descript 11%, rocks 3%. No correlations between event symptoms, hospital presentation, radiographs and foreign body presence. Event history, hospital presentation, and radiographs are insufficient in proving the absence of a radiolucent foreign body. Patients with suspected radiolucent foreign body aspiration should undergo diagnostic bronchoscopy prior to discharge. Copyright © 2013 Elsevier Inc. All rights reserved.

  20. The Gap between Aspiration and Practice

    ERIC Educational Resources Information Center

    Tuckett, Alan

    2013-01-01

    At the time of the fifth UNESCO international conference on adult education (CONFINTEA V) in Hamburg in 1997, it seemed that a resilient alliance of governments and civil society organizations had been created. This alliance would have the commitment and cooperation needed to pursue the ambitious aspirations captured in the 10 themes of the…

  1. Female Aspirants to the Roman Catholic Priesthood.

    ERIC Educational Resources Information Center

    Celmer, Virginia; Winer, Jane L.

    1990-01-01

    Investigated Holland vocational-personality types, job satisfaction, and psychological dysfunction among 85 parish priests, 55 nonparish priests, and 235 women who aspire to, but are barred from, ordination in the Roman Catholic Church. Found women's Holland-type code was most similar to code of clergy member as assigned by Dictionary of Holland…

  2. The Gap between Aspiration and Practice

    ERIC Educational Resources Information Center

    Tuckett, Alan

    2013-01-01

    At the time of the fifth UNESCO international conference on adult education (CONFINTEA V) in Hamburg in 1997, it seemed that a resilient alliance of governments and civil society organizations had been created. This alliance would have the commitment and cooperation needed to pursue the ambitious aspirations captured in the 10 themes of the…

  3. Turban pin aspiration: new fashion, new syndrome.

    PubMed

    Ilan, Ophir; Eliashar, Ron; Hirshoren, Nir; Hamdan, Kasem; Gross, Menachem

    2012-04-01

    Turban pin aspiration syndrome is a new clinical entity afflicting young Islamic girls wearing a turban.The goal of this study was to present our experience in diagnosis and treatment of this new entity, define its clinical and epidemiologic features, and shed a new light on the role of fashion in the increased incidence. A retrospective study in a tertiary university hospital. Review of clinical parameters and epidemiologic features of 26 patients diagnosed with turban pin aspiration syndrome admitted to the Hadassah-Hebrew University Hospitals in Jerusalem from 1990 to 2010. All patients were Muslim females with an average age of 16 years. In all cases, the history was positive for accidental aspiration. Most of the pins were located in the trachea (42%). In 20 cases, the pins were extracted by rigid bronchoscopy without major complications. Fluoroscopy-assisted rigid bronchoscopy was used successfully in three cases. In one case, the object was self-ejected by coughing before the bronchoscopy, and two patients were referred to the chest unit for thoracotomy. Clinicians should be aware of this distinct form of foreign body aspiration, its method of diagnosis, and extraction techniques. A cultural investigation showed a difference in the turban-fastening technique of young girls as compared with their mothers. Removal by rigid bronchoscopy is a safe method with a high success rate and should be considered as the preferred extraction method of choice. Copyright © 2012 The American Laryngological, Rhinological, and Otological Society, Inc.

  4. Aspiring Girls: Great Expectations or Impossible Dreams?

    ERIC Educational Resources Information Center

    Richards, Gill; Posnett, Carol

    2012-01-01

    This study explores girls' aspirations for their future. The context was an ex-coalmining area where concerns had been raised by the local authority about the levels of girls' achievement. The focus of the research was the views of Year 6 girls as they prepared for their transition to secondary school and Year 11 girls as they prepared for their…

  5. Aspiration pneumonia in children: an iconographic essay*

    PubMed Central

    de Oliveira, Gabriel Antonio; Pessanha, Laís Bastos; Guerra, Luiz Felipe Alves; Martins, Diego Lima Nava; Rondina, Ronaldo Garcia; Silva, Jamine Ronacher Passos

    2015-01-01

    In most cases of aspiration pneumonia in children, the disease is specific to this age group. Clinical and radiological correlation is essential for the diagnosis. The present pictorial essay is aimed at showing typical images of the most common etiologies. PMID:26811557

  6. Transthoracic needle aspiration in solitary pulmonary nodule

    PubMed Central

    Yang, Wen; Jiang, Hongli; Khan, Ali Nawaz; Allen, Carolyn; Bertolaccini, Luca

    2017-01-01

    With improved awareness of public health and the recent advances in various imaging technologies, the detection rate of solitary pulmonary nodules (SPN) is continuously increasing. Transthoracic needle aspiration (TTNA) has represented a major approach for the diagnosis and differential diagnosis of pulmonary masses, owing to its simplicity and minimal invasiveness. This paper demonstrates the role of TTNA in SPN. PMID:28331827

  7. Factors Influencing High School Students' Career Aspirations

    ERIC Educational Resources Information Center

    Tang, Mei; Pan, Wei; Newmeyer, Mark D.

    2008-01-01

    This article explores the factors influencing high school students' career aspirations with a study analyzing 141 high school students. The Social Cognitive Career Development Model was utilized to examine the interactive relationships among learning experiences, career self-efficacy, outcome expectations, career interests, and career choices. The…

  8. Occupational Aspirations and Expectations of Australian Adolescents

    ERIC Educational Resources Information Center

    Patton, Wendy; Creed, Peter

    2007-01-01

    Adolescents across the five years of high school (169 females and 164 males) completed a survey that identified occupational status aspirations and expectations coded into six types-- realistic, investigative, artistic, social, enterprising, or conventional--according to the RIASEC model (Holland, 1997). As the focus of the study was to explore…

  9. Another Opinion No Inspiration, No Aspirations

    ERIC Educational Resources Information Center

    Brown, Donna W.

    2004-01-01

    School library media specialists are the first to witness the malaise that permeates American schools threatening the future of our society. Believing that personal lack of aspirations, our failure to encourage reading for pure enjoyment, and society's disrespect toward education has left a void in our children that is filled with apathy.

  10. Occupational Aspirations and Expectations of Australian Adolescents

    ERIC Educational Resources Information Center

    Patton, Wendy; Creed, Peter

    2007-01-01

    Adolescents across the five years of high school (169 females and 164 males) completed a survey that identified occupational status aspirations and expectations coded into six types-- realistic, investigative, artistic, social, enterprising, or conventional--according to the RIASEC model (Holland, 1997). As the focus of the study was to explore…

  11. The Astrobiology Space Infrared Explorer (ASPIRE) Mission

    NASA Astrophysics Data System (ADS)

    Cruikshank, Dale P.; Sandford, S. A.; Roellig, T. L.; ASPIRE Team

    2009-01-01

    The Astrobiology Space Infrared Explorer (ASPIRE) Mission is one of the Origins Probe Mission Concepts that is currently being studied in preparation for inputs to the upcoming Decadal Survey. The mission is a cooled 1-m class telescope optimized to efficiently obtain high quality infrared spectra in the 2.5-36 micron wavelength region. The principal goal of the mission is to detect, identify, and determine the abundance of molecular species, particularly organics, throughout the universe. This will be done by obtaining spectra for a comprehensive range of Solar System, galactic, and extra-galactic environments and the interfaces between them. ASPIRE will be capable of obtaining continuous moderate resolution spectra from 2.5-36 microns at spectral resolutions of about 2500 (2.5-20 microns) and 900 (20-36 microns). ASPIRE will also be able to obtain high resolution spectra (resolutions of 25,000) over selected windows in the 3.1-18 micron region. The ASPIRE suite of instruments provides the ability to study both gas-phase and solid-state materials in space. The PI for the mission is Scott Sandford and major mission partners include NASA-Ames, JPL, and Ball Aerospace.

  12. Employment, Academic and Extracurricular Contributors to College Aspirations

    ERIC Educational Resources Information Center

    McGaha, Valerie; Fitzpatrick, Jacki

    2010-01-01

    Although there have been many studies on college entrance and aspirations, little attention has been paid to post-high school adults (who enter the workworld rather than college). it is possible that post-high school adults still have college aspirations, and it would be valuable to identify the factors that foster such aspirations. This study…

  13. [Spatial Cognition and Episodic Memory Formation in the Limbic Cortex].

    PubMed

    Kobayashi, Yasushi

    2017-04-01

    The limbic lobe defined by Broca is a cortical region with highly diverse structure and functions, and comprises the paleo-, archi-, and neocortices as well as their transitional zones. In the limbic lobe, Brodmann designated areas 27, 28, 34, 35, and 36 adjacent to the hippocampus, and areas 23, 24, 25, 26, 29, 30, 31, 32, and 33 around the corpus callosum. In the current literature, areas 27 and 28 correspond to the presubiculum and entorhinal cortex, respectively. Area 34 represents the cortico-medial part of the amygdaloid complex. Areas 35 and 36 roughly cover the perirhinal and parahippocampal cortices. Areas 24, 25, 32, and 33 belong to the anterior cingulate gyrus, while areas 23, 26, 29, 30, and 31 to the posterior cingulate gyrus. Areas 25, 32, and the anteroinferior portion of area 24 are deeply involved in emotional responses, particularly in their autonomic functions, through reciprocal connections with the amygdaloid complex, anterior thalamus and projections to the brainstem and spinal visceral centers. Areas 29 and 30 have dense reciprocal connections with areas 23 and 31, the dorsolateral prefrontal areas, and the regions related to the hippocampus. They play pivotal roles in mediating spatial cognition, working memory processing, and episodic memory formation.

  14. Respective Role of the Dorsal Hippocampus and the Entorhinal Cortex during the Recombination of Previously Learned Olfactory-Tactile Associations in the Rat

    ERIC Educational Resources Information Center

    Boisselier, Lise; Ferry, Barbara; Gervais, Rémi

    2017-01-01

    The hippocampal formation has been extensively described as a key component for object recognition in conjunction with place and context. The present study aimed at describing neural mechanisms in the hippocampal formation that support olfactory-tactile (OT) object discrimination in a task where space and context were not taken into account. The…

  15. Young APOE[subscript 4] Targeted Replacement Mice Exhibit Poor Spatial Learning and Memory, with Reduced Dendritic Spine Density in the Medial Entorhinal Cortex

    ERIC Educational Resources Information Center

    Rodriguez, Gustavo A.; Burns, Mark P.; Weeber, Edwin J.; Rebeck, G. William

    2013-01-01

    The apolipoprotein E4 ("APOE-[epsilon]4") allele is the strongest genetic risk factor for developing late-onset Alzheimer's disease, and may predispose individuals to Alzheimer's-related cognitive decline by affecting normal brain function early in life. To investigate the impact of human APOE alleles on cognitive performance in mice, we trained…

  16. Differences in Visual-Spatial Input May Underlie Different Compression Properties of Firing Fields for Grid Cell Modules in Medial Entorhinal Cortex

    DTIC Science & Technology

    2015-11-19

    differentials to link the result to the angular velocities. The two resulting equations are relate to each other through the common Visual-Spatial Input...cell firing fields. This indicates that different grid cell modules might have differential properties for computing location based on visual cues, or...fields. These differences could correspond to different posi- tions within the visual field of the animal . This model puts forth a testable hypothesis

  17. Respective Role of the Dorsal Hippocampus and the Entorhinal Cortex during the Recombination of Previously Learned Olfactory-Tactile Associations in the Rat

    ERIC Educational Resources Information Center

    Boisselier, Lise; Ferry, Barbara; Gervais, Rémi

    2017-01-01

    The hippocampal formation has been extensively described as a key component for object recognition in conjunction with place and context. The present study aimed at describing neural mechanisms in the hippocampal formation that support olfactory-tactile (OT) object discrimination in a task where space and context were not taken into account. The…

  18. Young APOE[subscript 4] Targeted Replacement Mice Exhibit Poor Spatial Learning and Memory, with Reduced Dendritic Spine Density in the Medial Entorhinal Cortex

    ERIC Educational Resources Information Center

    Rodriguez, Gustavo A.; Burns, Mark P.; Weeber, Edwin J.; Rebeck, G. William

    2013-01-01

    The apolipoprotein E4 ("APOE-[epsilon]4") allele is the strongest genetic risk factor for developing late-onset Alzheimer's disease, and may predispose individuals to Alzheimer's-related cognitive decline by affecting normal brain function early in life. To investigate the impact of human APOE alleles on cognitive performance in mice, we trained…

  19. Medial reward and lateral non-reward orbitofrontal cortex circuits change in opposite directions in depression.

    PubMed

    Cheng, Wei; Rolls, Edmund T; Qiu, Jiang; Liu, Wei; Tang, Yanqing; Huang, Chu-Chung; Wang, XinFa; Zhang, Jie; Lin, Wei; Zheng, Lirong; Pu, JunCai; Tsai, Shih-Jen; Yang, Albert C; Lin, Ching-Po; Wang, Fei; Xie, Peng; Feng, Jianfeng

    2016-12-01

    The first brain-wide voxel-level resting state functional connectivity neuroimaging analysis of depression is reported, with 421 patients with major depressive disorder and 488 control subjects. Resting state functional connectivity between different voxels reflects correlations of activity between those voxels and is a fundamental tool in helping to understand the brain regions with altered connectivity and function in depression. One major circuit with altered functional connectivity involved the medial orbitofrontal cortex Brodmann area 13, which is implicated in reward, and which had reduced functional connectivity in depression with memory systems in the parahippocampal gyrus and medial temporal lobe, especially involving the perirhinal cortex Brodmann area 36 and entorhinal cortex Brodmann area 28. The Hamilton Depression Rating Scale scores were correlated with weakened functional connectivity of the medial orbitofrontal cortex Brodmann area 13. Thus in depression there is decreased reward-related and memory system functional connectivity, and this is related to the depressed symptoms. The lateral orbitofrontal cortex Brodmann area 47/12, involved in non-reward and punishing events, did not have this reduced functional connectivity with memory systems. Second, the lateral orbitofrontal cortex Brodmann area 47/12 had increased functional connectivity with the precuneus, the angular gyrus, and the temporal visual cortex Brodmann area 21. This enhanced functional connectivity of the non-reward/punishment system (Brodmann area 47/12) with the precuneus (involved in the sense of self and agency), and the angular gyrus (involved in language) is thus related to the explicit affectively negative sense of the self, and of self-esteem, in depression. A comparison of the functional connectivity in 185 depressed patients not receiving medication and 182 patients receiving medication showed that the functional connectivity of the lateral orbitofrontal cortex Brodmann

  20. Efferent connections of the orbitofrontal cortex in the marmoset (Saguinus oedipus).

    PubMed

    Leichnetz, G R; Astruc, J

    1975-02-07

    Unilateral partial ablations were made in the orbitofrontal cortex of 4 adult marmosets (Saguinus oedipus) and fiber degeneration was traced using the Nauta-Gygax and Fink-Heimer selective silver impregnation techniques. Corticocortical projections were found to the ipsilateral convexity and medial aspect of the frontal lobe and to the homologous orbitofrontal areas of the contralateral hemisphere. Fiber degeneration was followed through the uncinate fascicle to the temporal and insular cortices, and caudally into the rostrolateral entorhinal cortex. Other fibers joined the cingulum bundle and terminated throughout the cingulate cortex. Subcortical projections were observed to the lateral and basal amygdaloid nuclei, caudate head, ventrolateral putamen and ventral claustrum. The lateral preoptic and hypothalamic areas received a small number of fibers, as did the intralaminar and reticular thalamic nuclei. The dorsomedial nucleus of the thalamus was recipient of a large group of fibers which followed the ventral internal capsule and joined the inferior thalamic peduncle to terminate there. Preterminal debris appeared heaviest in the dorsomedial thalamic nucleus, pars magnocellularis (MDmc) in more caudal orbital lesions. A subthalamic projection to field H of Forel was observed. A small number of fibers terminated in the lateral midbrain tegmentum, but no appreciable fiber degeneration was observed more caudally than the midbrain. These results are compared in some areas to findings in the rhesus monkey. The possibility of a topical organization in the orbital cortical and thalamic projections is discussed.

  1. Ultrasonic gas alloy atomization under near-zero aspiration pressure

    NASA Astrophysics Data System (ADS)

    Yan, Pengfei; Wang, Deping; Yan, Biao

    2015-04-01

    In this paper, ultrasonic gas atomization (USGA) of Zn-Al under near-zero aspiration pressure was discussed. The protrusion length of delivery tube was modified to adjust the aspiration pressure. Under near-zero aspiration pressure, melt filming was observed by camera and more fine powders were produced. While under larger subambient aspiration pressure, melt filming was unavailable, corresponding to less fine powders. The results suggest that the position of the wake near the delivery tube can be optimized under near-zero aspiration. Less protrusion of delivery tube reduces the energy loss in gas flow deflection. Both facilitate to produce finer powders.

  2. Risk and outcome of aspiration pneumonia in a city hospital.

    PubMed Central

    Jones, J.

    1993-01-01

    Because aspiration pneumonia contributes significantly to morbidity and mortality in hospitalized patients, this study was undertaken to identify risk factors for morbidity and mortality associated with aspiration pneumonia. Patients with a discharge diagnosis of aspiration pneumonia in 1985 and 1990 were studied. Factors associated with death from aspiration pneumonia were: altered mental status, cerebrovascular accident, endotracheal intubation, tachycardia, and hypoxemia. Fever, cough, and unilateral infiltrates on chest radiograph were associated with survival. Attention to proper positioning of comatose patients, aggressive treatment of gastroesophageal reflux, and strict attention to endotracheal tubes and tracheostomies should decrease the morbidity and mortality associated with aspiration pneumonia. PMID:8350375

  3. Perirhinal Cortex Hyperexcitability in Pilocarpine-Treated Epileptic Rats

    PubMed Central

    Benini, Ruba; Longo, Daniela; Biagini, Giuseppe; Avoli, Massimo

    2016-01-01

    The perirhinal cortex (PC), which is heavily connected with several epileptogenic regions of the limbic system such as the entorhinal cortex and amygdala, is involved in the generation and spread of seizures. However, the functional alterations occurring within an epileptic PC network are unknown. Here, we analyzed this issue by using in vitro electrophysiology and immunohistochemistry in brain tissue obtained from pilocarpine-treated epileptic rats and age-matched, nonepileptic controls (NECs). Neurons recorded intracellularly from the PC deep layers in the two experimental groups had similar intrinsic and firing properties and generated spontaneous depolarizing and hyperpolarizing postsynaptic potentials with comparable duration and amplitude. However, spontaneous and stimulus-induced epileptiform discharges were seen with field potential recordings in over one-fifth of pilocarpine-treated slices but never in NEC tissue. These network events were reduced in duration by antagonizing NMDA receptors and abolished by NMDA + non-NMDA glutamatergic receptor antagonists. Pharmacologically isolated isolated inhibitory postsynaptic potentials had reversal potentials for the early GABAA receptor-mediated component that were significantly more depolarized in pilocarpine-treated cells. Experiments with a potassium-chloride cotransporter 2 antibody identified, in pilocarpine-treated PC, a significant immunostaining decrease that could not be explained by neuronal loss. However, interneurons expressing parvalbumin and neuropeptide Y were found to be decreased throughout the PC, whereas cholecystokinin-positive cells were diminished in superficial layers. These findings demonstrate synaptic hyper-excitability that is contributed by attenuated inhibition in the PC of pilocarpine-treated epileptic rats and underscore the role of PC networks in temporal lobe epilepsy. PMID:20865722

  4. Dysphagia, dystussia, and aspiration pneumonia in elderly people.

    PubMed

    Ebihara, Satoru; Sekiya, Hideki; Miyagi, Midori; Ebihara, Takae; Okazaki, Tatsuma

    2016-03-01

    Despite the development and wide distribution of guidelines for pneumonia, death from pneumonia is increasing due to population aging. Conventionally, aspiration pneumonia was mainly thought to be one of the infectious diseases. However, we have proven that chronic repeated aspiration of a small amount of sterile material can cause the usual type of aspiration pneumonia in mouse lung. Moreover, chronic repeated aspiration of small amounts induced chronic inflammation in both frail elderly people and mouse lung. These observations suggest the need for a paradigm shift of the treatment for pneumonia in the elderly. Since aspiration pneumonia is fundamentally based on dysphagia, we should shift the therapy for aspiration pneumonia from pathogen-oriented therapy to function-oriented therapy. Function-oriented therapy in aspiration pneumonia means therapy focusing on slowing or reversing the functional decline that occurs as part of the aging process, such as "dementia → dysphagia → dystussia → atussia → silent aspiration". Atussia is ultimate dysfunction of cough physiology, and aspiration with atussia is called silent aspiration, which leads to the development of life-threatening aspiration pneumonia. Research pursuing effective strategies to restore function in the elderly is warranted in order to decrease pneumonia deaths in elderly people.

  5. Multi-dimension aspiration control mode in phacoemulsification.

    PubMed

    Wang, Xiangqun; He, Mingguang; Zeng, Junwen

    2005-09-01

    Multi-dimension aspiration control mode was put forward in this study. Accuracy of multi-dimension aspiration control model was compared to simple traditional pedal control model. Induced by high aspiration pressure (200-250 mmHg), hard nucleus (> OR = Grade III ) of senile cataract was chopped before phacoemulsification in 170 patients (174 eyes). Ninety-one patients (94 eyes) accepted multi-dimension aspiration control model in which aspiration direction, distance and targets prevention were adjusted by phaco-tip besides traditional pedal control. Another 79 patients (80 eyes) were compared as reviewed group, aspiration of which was controlled simply by traditional pedal control. Postcapsular rupture rates (PCRR) were compared between two groups. Multi-dimension control model could make the terminal effects cooperate with phacoemulsification more precisely and protect post capsular from damage (chi(2) =5.41, P < 0.02). Multi-dimension control model could improve the accuracy of aspiration effects and protect postcapsular from damage.

  6. Amebic liver abscess: fine needle aspiration diagnosis.

    PubMed

    Mokhtari, Maral; Kumar, Perikala Vijayananda

    2014-01-01

    To describe the findings in fine needle aspiration (FNA) of an amebic liver abscess (ALA). Seven patients (6 men and 1 woman between 52 and 60 years of age) treated for amebic dysentery with multiple liver lesions were selected for ultrasound (US)-guided FNA. The clinical differential diagnosis was malignancy. Abdominal US of the patients revealed multiple, variably sized, well-defined, hypoechoic, cystic liver lesions. FNA of these lesions was performed. Smears of the aspirated material showed necrotic material with mixed inflammatory cells and Entamoeba histolytica trophozoites consisting of round blue bodies with well-defined borders containing a single, eccentrically located nucleus with central karyosome and engulfed red blood cells in the cytoplasm. There were also Charcot-Leyden crystals. ALA was diagnosed. FNA can yield the correct diagnosis of ALA and allows early initiation of treatment. ALA should be considered in the differential diagnosis of space-occupying lesions of the liver. © 2014 S. Karger AG, Basel.

  7. Fine needle aspiration biopsy of ophthalmic tumors☆

    PubMed Central

    Singh, Arun D.; Biscotti, Charles V.

    2012-01-01

    A majority of intraocular tumors can be diagnosed based on clinical examination and ocular imaging studies, which obviate the need for diagnostic ophthalmic fine needle aspiration biopsy (FNAB). Overall, diagnostic accuracy of ophthalmic FNAB is high but limited cellularity can compromise the diagnostic potential of ophthalmic aspirate samples. The role of ophthalmic FNAB is limited in retinal tumors. Orbital FNAB should be considered in the evaluation of lacrimal gland tumors, orbital metastasis, and lymphoproliferative lesions. Negative cytologic diagnosis of malignancy should not be considered unequivocal proof that an intraocular malignancy does not exist. With improved understanding of genetic prognostic factors of uveal melanoma, ophthalmic FNAB is gaining popularity for prognostic purposes in combination with eye conserving treatment of the primary tumor. In special clinical indications, ancillary studies such as immunohistochemistry and FISH can be performed on ophthalmic FNAB samples. Assistance of an experienced cytopathologist cannot be overemphasized. PMID:23960981

  8. The sweet lung: Chewing gummi bear aspiration

    PubMed Central

    Tavladaki, Theonimfi; Fitrolaki, Michaela-Diana; Spanaki, Anna-Maria; Ilia, Staurula; Geromarkaki, Elissabet; Briassoulis, George

    2012-01-01

    Inhalation of foreign bodies, a leading cause of accidental death, is most common in preschool children. In this article we report our experience with a 5-year-old Greek girl who presented with a 24-hour history of sore throat, chest pain, and shortness of breath. Emergency bronchoscopy was performed and multiple small chewing gummi bear (HARIBO) particles impacted in the orifices of the right main bronchus and right lobar and segmentalinic bronchi were successfully removed and aspirated. Aspiration of gummi bears, which is for the first time reported, may cause a silent choking episode leading to life-threatening bronchi obstruction at multiple sites, even in children older than 4 years. PMID:22919167

  9. Neuropsychology of prefrontal cortex

    PubMed Central

    Siddiqui, Shazia Veqar; Chatterjee, Ushri; Kumar, Devvarta; Siddiqui, Aleem; Goyal, Nishant

    2008-01-01

    The history of clinical frontal lobe study is long and rich which provides valuable insights into neuropsychologic determinants of functions of prefrontal cortex (PFC). PFC is often classified as multimodal association cortex as extremely processed information from various sensory modalities is integrated here in a precise fashion to form the physiologic constructs of memory, perception, and diverse cognitive processes. Human neuropsychologic studies also support the notion of different functional operations within the PFC. The specification of the component ‘executive’ processes and their localization to particular regions of PFC have been implicated in a wide variety of psychiatric disorders. PMID:19742233

  10. Aspiration catheter for percutaneous thrombectomy: clinical results.

    PubMed

    Guenther, R W; Vorwerk, D

    1990-04-01

    The clinical application of an aspiration thrombectomy system is presented. The system consists of a 7-F Teflon catheter with a rotating coaxial propeller-tipped wire. Thrombectomy was successful in treating occlusion of two femoropopliteal arteries and one hemodialysis implant but was not completely successful in a draining shunt vein. Preliminary results are encouraging; mechanical thrombectomy may offer an alternative to local lysis therapy.

  11. Facial Blast Injury Resulting in Sand Aspiration

    DTIC Science & Technology

    2009-01-01

    recent case of a blast-injury survivor in Iraq with findings consistent with sand aspiration on computed tomography (CT) and review presentation...which may contain material such as calcium carbonate or aluminum silicate, produces characteristic findings on both computed tomography (CT) and...extubated. On hospital day 2, copious thick fluid described as “muddy” was suctioned from the respiratory tract, at which time a well tolerated

  12. Interneurons, tau and amyloid-β in the piriform cortex in Alzheimer's disease.

    PubMed

    Saiz-Sanchez, Daniel; De la Rosa-Prieto, Carlos; Ubeda-Banon, Isabel; Martinez-Marcos, Alino

    2015-07-01

    Impaired olfaction has been described as an early symptom of Alzheimer's disease. Neuroanatomical changes underlying this deficit in the olfactory system are largely unknown. Interestingly, neuropathology begins in the transentorhinal cortex and extends to the neighboring limbic system and basal telencephalic structures that mediate olfactory processing, including the anterior olfactory nucleus and olfactory bulb. The human piriform cortex has been described as a crucial area in odor quality coding; disruption of this region mediates early olfactory deficits in Alzheimer's disease. Most neuropathological investigations have focused on the entorhinal cortex and hippocampus, whereas the piriform cortex has largely been neglected. This work aims to characterize the expression of the neuropathological amyloid-β peptide, tau protein and interneuron population markers (calretinin, parvalbumin and somatostatin) in the piriform cortex of ten Alzheimer-diagnosed (80.4 ± 8.3 years old) and five control (69.6 ± 11.1) cases. Here, we examined the distribution of different interneuronal markers as well as co-localization of interneurons and pathological markers. Results indicated preferential vulnerability of somatostatin- (p = 0.0001 < α = 0.05) and calretinin-positive (p = 0.013 < α = 0.05) cells that colocalized with amyloid-β peptide, while the prevalence of parvalbumin-positive cells was increased (p = 0.045 < α = 0.05) in the Alzheimer's cases. These data may help to reveal the neural basis of olfactory deficits linked to Alzheimer's disease as well as to characterize neuronal populations preferentially vulnerable to neuropathology in regions critically involved in early stages of the disease.

  13. Pepsin as a Marker for Pulmonary Aspiration

    PubMed Central

    Metheny, Norma A.; Chang, Yie-Hwa; Ye, Jing Song; Edwards, Sharon J.; Defer, Julie; Dahms, Thomas E.; Stewart, Barbara J.; Stone, Kathleen S.; Clouse, Ray E.

    2008-01-01

    BACKGROUND Although assessment for aspiration of small volumes of gastric contents in tube-fed patients receiving mechanical ventilation is important, available methods for this purpose are not wholly satisfactory. A potential method is immunoassay of tracheal secretions for the gastric enzyme pepsin. OBJECTIVES To determine the frequency with which pepsin in suctioned tracheal secretions from acutely ill, tube-fed patients receiving mechanical ventilation could be detected via an immunoassay. METHODS A convenience sample of 136 specimens of suctioned tracheal secretions was collected from 30 acutely ill, tube-fed adults receiving mechanical ventilation. Multiple samples were obtained from 26 of the 30 patients (range, 2−11 per subject). An immunoassay with rooster polyclonal antibodies to purified human pepsin was used to detect pepsin in the secretions. RESULTS Fourteen specimens tested positive for pepsin. Secretions from 5 patients accounted for the 14 pepsin-positive results. A significant relationship was found between the position of the head of the bed and the presence of pepsin in tracheal secretions (P< .001). Of the 14 pepsin-positive specimens, 13 (92.9%) were obtained from subjects in a flat position. CONCLUSIONS A pepsin immunoassay can be used to detect pepsin in human tracheal secretions. If pepsin in tracheal secretions is considered an indicator of aspiration of gastric contents, aspiration occurred in 5 of the 30 subjects. A flat position is strongly associated with the presence of pepsin in tracheal secretions. PMID:11888127

  14. Percutaneous gallbladder aspiration for acute cholecystitis

    PubMed Central

    Rassameehiran, Supannee; Nugent, Kenneth

    2016-01-01

    Early cholecystectomy for patients with acute cholecystitis may not be possible in some clinical settings. Percutaneous gallbladder aspiration (PGBA) offers an alternative approach, but the benefits and risks of this procedure are unclear. We synthesized data on the outcomes of PGBA in acute cholecystitis patients using data sources from online databases, including MEDLINE and EMBASE, and bibliographies of included studies from January 2000 through December 2015. Two reviewers independently reviewed and critiqued the quality of each study. Seven eligible studies met our criteria. The success rates in single PGBA and repetitive PGBA (2–4 times) were 50% to 93% and 76% to 96%, respectively. Complication rates were 0% to 8% and were unrelated to the size of needle gauge used for aspiration and the number of aspirations. Salvage percutaneous cholecystostomy (PC) and urgent surgery were required in 0% to 43% of patients and 0% to 4% of patients, respectively. Two studies with antibiotic instillation had clinical success rates of 95% and 96%. In conclusion, repetitive PGBA combined with antibiotic instillation and salvage PC are useful alternatives to early cholecystectomy in patients with acute cholecystitis. PMID:27695167

  15. Optogenetic Stimulation of Lateral Amygdala Input to Posterior Piriform Cortex Modulates Single-Unit and Ensemble Odor Processing.

    PubMed

    Sadrian, Benjamin; Wilson, Donald A

    2015-01-01

    Olfactory information is synthesized within the olfactory cortex to provide not only an odor percept, but also a contextual significance that supports appropriate behavioral response to specific odor cues. The piriform cortex serves as a communication hub within this circuit by sharing reciprocal connectivity with higher processing regions, such as the lateral entorhinal cortex and amygdala. The functional significance of these descending inputs on piriform cortical processing of odorants is currently not well understood. We have employed optogenetic methods to selectively stimulate lateral and basolateral amygdala (BLA) afferent fibers innervating the posterior piriform cortex (pPCX) to quantify BLA modulation of pPCX odor-evoked activity. Single unit odor-evoked activity of anesthetized BLA-infected animals was significantly modulated compared with control animal recordings, with individual cells displaying either enhancement or suppression of odor-driven spiking. In addition, BLA activation induced a decorrelation of odor-evoked pPCX ensemble activity relative to odor alone. Together these results indicate a modulatory role in pPCX odor processing for the BLA complex. This interaction could contribute to learned changes in PCX activity following associative conditioning, as well as support alternate patterns of odor processing that are state-dependent.

  16. Molecular signalling pathways in the cerebral cortex are required for retrieval of one-trial avoidance learning in rats.

    PubMed

    Barros, D M; Izquierdo, L A; Mello e Souza, T; Ardenghi, P G; Pereira, P; Medina, J H; Izquierdo, I

    2000-09-01

    Rats were implanted bilaterally with cannulae in the CA1 region of the dorsal hippocampus, the entorhinal cortex, anterior cingulate cortex, posterior parietal cortex, or the basolateral complex of the amygdala. The animals were trained in one-trial step-down inhibitory avoidance and tested 24 h later. Prior (10 min) to the retention test, through the cannulae, they received 0.5 microl infusions of a vehicle (2% dimethylsulfoxide in saline), or of the following drugs dissolved in the vehicle: the glutamate NMDA receptor blocker, aminophosphonopentanoic acid (AP5, 2.0 or 5.0 microg), the AMPA receptor blocker, 6,7-dinitroquinoxaline-2,3 (1H,4H)dione (DNQX, 0.4 or 1.0 microg), the metabotropic receptor antagonist, methylcarboxyphenylglycine (MCPG, 0.5 or 2.5 microg), the inhibitor of cAMP-dependent protein kinase (PKA), Rp-cAMPs (0.1 or 0.5 microg), the PKA stimulant, Sp-cAMPs (0.5 microg), or the inhibitor of the mitogen-activated protein kinase (MAPK), PD098059 (10 or 50 microM). All these drugs, at the same doses, had been previously found to alter long-term memory formation of this task. Here, retrieval test performance was blocked by DNQX, MCPG, Rp-cAMPs and PD098059 and enhanced by Sp-cAMPs infused into CA1 or the entorhinal cortex. The drugs had similar effects when infused into the parietal or anterior cingulate cortex, except that in these two areas AP5 also blocked retrieval, and in the cingulate cortex DNQX had no effect. Infusions into the basolateral amygdala were ineffective except for DNQX, which hindered retrieval. None of the treatments that affected retrieval had any influence on performance in an open field or in a plus maze; therefore, their effect on retention testing can not be attributed to an influence on locomotion, exploration or anxiety. The results indicate that the four cortical regions studied participate actively in, and are necessary for, retrieval of the one-trial avoidance task. They require metabotropic and/or NMDA glutamate

  17. Aspirations, Expectations and Delinquency: The Moderating Effect of Impulse Control.

    PubMed

    Mahler, Alissa; Simmons, Cortney; Frick, Paul J; Steinberg, Laurence; Cauffman, Elizabeth

    2017-07-01

    Although prior research finds a robust link between delinquent behavior and expectations, or an adolescent's perceived likelihood of obtaining one's future goals, fewer studies have evaluated aspirations, or the perceived importance of achieving one's goals. In addition, few studies consider how individual traits such as impulsivity affect the degree to which expectations and aspirations motivate or deter delinquent behavior. We contribute to this body of research by evaluating the independent effects of expectations and aspirations, and the aspiration-expectation gap (i.e., strain) on delinquent behavior during the year following an adolescent's first arrest using a large (N = 1117), racially/ethnically diverse sample of male adolescents (46.55% Latino, 35.81% Black, 14.95% White, and 2.69% Other race). In addition, we considered how impulse control interacts with expectations, aspirations, and strain to motivate behavior. Our results indicated that both aspirations, expectations and strain uniquely influence criminal behavior. Importantly, aspirations interacted with impulse control, such that aspirations affected delinquency only among youth with higher impulse control. Our findings suggest that aspirations may only influence behavior if youth also have the psychosocial capabilities to consider their future aspirations when behaving in the present.

  18. Dysphagia, dystussia, and aspiration pneumonia in elderly people

    PubMed Central

    Sekiya, Hideki; Miyagi, Midori; Ebihara, Takae; Okazaki, Tatsuma

    2016-01-01

    Despite the development and wide distribution of guidelines for pneumonia, death from pneumonia is increasing due to population aging. Conventionally, aspiration pneumonia was mainly thought to be one of the infectious diseases. However, we have proven that chronic repeated aspiration of a small amount of sterile material can cause the usual type of aspiration pneumonia in mouse lung. Moreover, chronic repeated aspiration of small amounts induced chronic inflammation in both frail elderly people and mouse lung. These observations suggest the need for a paradigm shift of the treatment for pneumonia in the elderly. Since aspiration pneumonia is fundamentally based on dysphagia, we should shift the therapy for aspiration pneumonia from pathogen-oriented therapy to function-oriented therapy. Function-oriented therapy in aspiration pneumonia means therapy focusing on slowing or reversing the functional decline that occurs as part of the aging process, such as “dementia → dysphagia → dystussia → atussia → silent aspiration”. Atussia is ultimate dysfunction of cough physiology, and aspiration with atussia is called silent aspiration, which leads to the development of life-threatening aspiration pneumonia. Research pursuing effective strategies to restore function in the elderly is warranted in order to decrease pneumonia deaths in elderly people. PMID:27076964

  19. Importance of diffuse aspiration bronchiolitis caused by chronic occult aspiration in the elderly.

    PubMed

    Matsuse, T; Oka, T; Kida, K; Fukuchi, Y

    1996-11-01

    Diffuse aspiration bronchiolitis (DAB) is a new term that we proposed to define a clinical entity that is characterized by a chronic inflammation of bronchioles caused by recurrent aspiration of foreign particles. In the present study, a total of 4,880 consecutive autopsies were reviewed and we found 31 patients with DAB (0.64%). To investigate the clinicopathologic features of DAB, the 23 patients with DAB (age, 81.2 +/- 6.2 years [mean +/- SD]), from whom clinical information was available, had their features compared to those of 40 randomly selected patients with aspiration pneumonia (age, 81.9 +/- 8.3 years [mean +/- SD]). Oropharyngeal dysphagia was observed in half of the patients with DAB, and two thirds of patients with DAB were bedridden. The onset of DAB was more insidious than aspiration pneumonia, and in half of the patients with DAB episodes of aspiration were unrecognized. Neurologic disorders (52.2%) and dementia (47.8%) were common associated diseases. Most patients with DAB showed signs of bronchorrhea, bronchospasm, and dyspnea. The macroscopic appearance of the cut surface of DAB lung showed diffusely scattered miliary yellowish nodules that resembled those of diffuse panbronchiolitis (DPB). Histologic findings of DAB were characterized by localization of chronic mural inflammation with foreign body reaction in bronchioles. Recurrence of small amounts of aspiration might play a role in the pathogenesis of DAB. In view of possible therapeutic intervention, we emphasized the importance of recognizing this entity and differentiating DAB from pulmonary diseases associated with bronchospasm in the elderly, in particular, late-onset asthma and DPB.

  20. Hurricane cortical aspiration technique: one-step continuous circular aspiration maneuver.

    PubMed

    Nakano, Celso Takashi; Motta, Antonio Francisco Pimenta; Hida, Wilson Takashi; Nakamura, Cristiane Mitie; Tzelikis, Patrick Frensel; Ruiz Alves, Milton; Werner, Liliana

    2014-04-01

    We describe a modification of the original standard radial aspiration technique. The modified technique--hurricane 1-step continuous circular cortical aspiration--has the potential to improve this part of phacoemulsification surgery with benefits in surgical time and possible decreases in fluid, corneal edema, and traction on the zonular fibers through better distribution of tractional forces. The first results were encouraging and without complications. No author has a financial or proprietary interest in any material or method mentioned. Copyright © 2014 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  1. [Neuroanatomy of Frontal Association Cortex].

    PubMed

    Takada, Masahiko

    2016-11-01

    The frontal association cortex is composed of the prefrontal cortex and the motor-related areas except the primary motor cortex (i.e., the so-called higher motor areas), and is well-developed in primates, including humans. The prefrontal cortex receives and integrates large bits of diverse information from the parietal, temporal, and occipital association cortical areas (termed the posterior association cortex), and paralimbic association cortical areas. This information is then transmitted to the primary motor cortex via multiple motor-related areas. Given these facts, it is likely that the prefrontal cortex exerts executive functions for behavioral control. The functional input pathways from the posterior and paralimbic association cortical areas to the prefrontal cortex are classified primarily into six groups. Cognitive signals derived from the prefrontal cortex are conveyed to the rostral motor-related areas to transform them into motor signals, which finally enter the primary motor cortex via the caudal motor-related areas. Furthermore, it has been shown that, similar to the primary motor cortex, areas of the frontal association cortex form individual networks (known as "loop circuits") with the basal ganglia and cerebellum via the thalamus, and hence are extensively involved in the expression and control of behavioral actions.

  2. When Aspirations Exceed Expectations: Quixotic Hope Increases Depression among Students

    PubMed Central

    Cruwys, Tegan

    2015-01-01

    A paradox exists in modern schooling: students are simultaneously more positive about the future and more depressed than ever. We suggest that these two phenomena may be linked. Two studies demonstrated that students are more likely to be depressed when educational aspirations exceed expectations. In Study 1 (N = 85) aspiring to a thesis grade higher than one expected predicted greater depression at the beginning and end of the academic year. In Study 2 (N = 2820) aspiring to a level of education (e.g., attending college) higher than one expected to achieve predicted greater depression cross-sectionally and five years later. In both cases the negative effects of aspiring high while expecting low persisted even after controlling for whether or not students achieved their educational aspirations. These findings highlight the danger of teaching students to aspire higher without also investing time and money to ensure that students can reasonably expect to achieve their educational goals. PMID:26352151

  3. When Aspirations Exceed Expectations: Quixotic Hope Increases Depression among Students.

    PubMed

    Greenaway, Katharine H; Frye, Margaret; Cruwys, Tegan

    2015-01-01

    A paradox exists in modern schooling: students are simultaneously more positive about the future and more depressed than ever. We suggest that these two phenomena may be linked. Two studies demonstrated that students are more likely to be depressed when educational aspirations exceed expectations. In Study 1 (N = 85) aspiring to a thesis grade higher than one expected predicted greater depression at the beginning and end of the academic year. In Study 2 (N = 2820) aspiring to a level of education (e.g., attending college) higher than one expected to achieve predicted greater depression cross-sectionally and five years later. In both cases the negative effects of aspiring high while expecting low persisted even after controlling for whether or not students achieved their educational aspirations. These findings highlight the danger of teaching students to aspire higher without also investing time and money to ensure that students can reasonably expect to achieve their educational goals.

  4. The use of oxytocin in nipple fluid aspiration.

    PubMed

    Zhang, Liping; Shao, Zhi-Ming; Beatty, Perrin; Sartippour, Maryam; Wang, He-Jing; Elashoff, Robert; Chang, Helena; Brooks, Mai N

    2003-01-01

    It has been shown that early detection of breast cancer saves lives. Recently there has been increasing interest in nipple aspirate fluid as a potential avenue for breast cancer diagnosis. One major challenge regarding studies of nipple aspirate fluid is the ability to obtain adequate samples. Here we describe the use of nasal oxytocin in a group of volunteer women in order to increase the yield of nipple aspirate fluid.

  5. Aspirating and Nonaspirating Swallow Sounds in Children: A Pilot Study.

    PubMed

    Frakking, Thuy; Chang, Anne; O'Grady, Kerry; David, Michael; Weir, Kelly

    2016-12-01

    Cervical auscultation (CA) may be used to complement feeding/swallowing evaluations when assessing for aspiration. There are no published pediatric studies that compare the properties of sounds between aspirating and nonaspirating swallows. To establish acoustic and perceptual profiles of aspirating and nonaspirating swallow sounds and determine if a difference exists between these 2 swallowing types. Aspiration sound clips were obtained from recordings using CA simultaneously undertaken with videofluoroscopic swallow study. Aspiration was determined using the Penetration-Aspiration Scale. The presence of perceptual swallow/breath parameters was rated by 2 speech pathologists who were blinded to the type of swallow. Acoustic data between groups were compared using Mann Whitney U-tests, while perceptual differences were determined by a test of 2 proportions. Combinations of perceptual parameters of 50 swallows (27 aspiration, 23 no aspiration) from 47 children (57% male) were statistically analyzed using area under a receiver operating characteristic (aROC), sensitivity, specificity, and positive and negative predictive values to determine predictors of aspirating swallows. The combination of post-swallow presence of wet breathing and wheeze and absence of GRS and normal breathing was the best predictor of aspiration (aROC = 0.82, 95% CI, 0.70-0.94). There were no significant differences between these 2 swallow types for peak frequency, duration, and peak amplitude. Our pilot study has shown that certain characteristics of swallow obtained using CA may be useful in the prediction of aspiration. However, further research comparing the acoustic swallowing sound profiles of normal children to children with dysphagia (who are aspirating) on a larger scale is required. © The Author(s) 2016.

  6. Cocaine balloon aspiration: successful removal with bronchoscopy.

    PubMed

    Cobaugh, D J; Schneider, S M; Benitez, J G; Donahoe, M P

    1997-09-01

    Ingestion of balloons containing illicit substances along with the potential toxic sequelae associated with these ingestions have been described in the literature. This report describes the successful bronchoscopic retrieval of a cocaine balloon after aspiration. A 39-year-old man was witnessed swallowing several balloons that were thought to contain heroin. Shortly after ingestion, the patient became unconscious and required nasotracheal intubation. Before intubation, several balloons were removed from the oropharynx. Naloxone 4 mg was administered en route to the emergency department (ED). Following naloxone, the patient awoke and became agitated and combative. On arrival in the ED, midazolam, succinylcholine, and vecuronium were required to manage his combativeness. Vital signs were: heart rate, 130 beats/min; blood pressure, 128/86 mm Hg; respirations, 12 breaths/min; temperature, 96.5 degrees F. A balloon and balloon tip were removed during lavage. Whole bowel irrigation with a polyethylene glycol electrolyte solution was initiated. A right upper lobe infiltrate was identified on chest X-ray and aspiration of a balloon was suspected. At bronchoscopy, a small yellow, intact balloon visualized in the basilar segment of the right lower lobe was removed. Toxicologic analysis of the balloon contents found cocaine. The rest of the patient's hospital course was unremarkable and he was discharged 5 days after admission. This case brings to light the potential concerns, such as respiratory compromise, associated with aspiration of small balloons in the body stuffer. Additionally, the potential for the development of toxicity if the balloon ruptures and toxin absorption occurs through through the lungs should be considered. Emergency physicians and toxicologists should be aware of this significant complication of packet ingestion in the body packer or stuffer and be prepared to intervene early during the course of the patient's treatment.

  7. Respiratory complications following hydrocarbon aspiration in children.

    PubMed

    Makrygianni, Evanthia A; Palamidou, Fani; Kaditis, Athanasios G

    2016-06-01

    Accidental hydrocarbon ingestion may lead to aspiration and chemical pneumonitis in children. In this review article, the clinical course of hydrocarbon pneumonitis, chest radiographic abnormalities, complications, and treatment interventions are summarized. Most children remain asymptomatic and without complications following ingestion of a hydrocarbon. In approximately 15% of ingestions, aspiration pneumonitis occurs and evolves over the first 6-8 hr presenting with fever, tachypnea, hypoxemia, and tachycardia. A symptom zenith is reached within 48 hr followed by progressive improvement. Up to 5% of pneumonitis cases progress rapidly to acute respiratory failure. Chest radiographic abnormalities develop by 4-8 hr after ingestion, but they are not always predictive of clinical pneumonitis. Patients with history of hydrocarbon ingestion should be monitored for 6-8 hr in the emergency department and a chest radiogram should be obtained at the end of the observation period. Spontaneous or induced emesis and gastric lavage have been related to aspiration pneumonitis. Children who are symptomatic are admitted to the hospital for cardiorespiratory status monitoring and supportive care. Approximately 90% of hospitalized patients have a benign clinical course. Increased work of breathing with or without altered sensorium and seizures are indications for admission to the intensive care unit. Hypoxemia unresponsive to supplemental oxygen and/or severe central nervous system involvement require mechanical ventilation. Corticosteroids do not seem to offer any benefit and antibiotics are administered in cases of bacterial superinfection. Pneumatoceles may become evident after the first 6-10 days of symptoms on follow-up chest radiograms and they resolve up to 6 months later. Pediatr Pulmonol. 2016;51:560-569. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  8. Performing a Better Bone Marrow Aspiration.

    PubMed

    Friedlis, Mayo F; Centeno, Christopher J

    2016-11-01

    Bone marrow aspiration (BMA) is increasingly being used to harvest stem cells for use in regenerative medicine. The focus of BMA in interventional orthopedics is to maximize the yield of mesenchymal stem cells. The authors present an improved method for BMA that involves fluoroscope or ultrasound guidance combined with anesthesia; in the authors' experience, it produces the highest possible stem cell yield and is well tolerated by patients. The authors provide a step-by-step guide to the process, along with a discussion of technical and other considerations and quick reference guides for ultrasound- and fluoroscope-guided BMA. Copyright © 2016 Elsevier Inc. All rights reserved.

  9. Aspiration Cytology Characterization of Inflammatory Masses

    PubMed Central

    Bottles, Kent; Miller, Theodore R.; Jeffrey, R. Brooke; Cohen, Michael B.; Stoloff, Amy; Hales, Martha; Ljung, Britt-Marie; Donegan, Elizabeth

    1986-01-01

    Fine-needle aspiration biopsy smears are useful in the workup of patients with abscesses and inflammatory masses. We report 37 cases classified into three groups: group I, in which a causative organism was seen on the smear; group II, in which a causative organism was cultured from a smear where organisms were not seen microscopically, and group III, in which the organism was not seen or cultured, but the smear findings were useful in determining further workup. ImagesFigure 1.Figure 2.Figure 3.Figure 4.Figure 5.Figure 6. PMID:2425496

  10. Effects of aspiration on fundamental frequency in Taiwanese syllables

    NASA Astrophysics Data System (ADS)

    Lai, Yuwen; Jongman, Allard

    2005-04-01

    The perturbation effect on vowel fundamental frequency (F0) by voiceless aspirated and unaspirated prevocalic obstruents is investigated in Taiwanese. It is well known that F0 is significantly higher after voiceless than voiced stops. However, the perturbation effect caused by aspiration has received much less attention. Twenty-eight minimal pairs contrasting in prevocalic aspiration across three different places of articulation from seven tonal categories in Taiwanese were recorded from two male and two female speakers. An acoustic study was conducted on a total of 1120 syllables. Onset, offset, and mean F0 as well as contours of the tones after the aspirated and unaspirated obstruents were compared. Results indicate that the onset and mean F0 are significantly higher when following aspirated obstruents but no difference was found in offset F0. Tonal contour comparison shows that the F0 raising effect triggered by aspirated obstruents disappears at 50-60% of the tone. Higher larynx and faster airflow rate are posited as the major factors for the higher F0 after voiceless aspirated obstruents. The present results warrant a reconsideration of the traditional theory of aspiration-induced tonal split according to which a tonal split resulted from the lowering of F0 due to aspiration.

  11. Role of aspiration-induced migration in cooperation

    NASA Astrophysics Data System (ADS)

    Yang, Han-Xin; Wu, Zhi-Xi; Wang, Bing-Hong

    2010-06-01

    Both cooperation and migration are ubiquitous in human society and animal world. In this Rapid Communication, we propose an aspiration-induced migration in which individuals will migrate to new sites provided that their payoffs are below some aspiration level. It is found that moderate aspiration level can best favor cooperative behavior. In particular, moderate aspiration level enables cooperator clusters to maintain and expand whereas induces defector clusters to disintegrate, thus promoting the diffusion of cooperation among population. Our results provide insights into understanding the role played by migration in the emergence of cooperative behavior.

  12. Silent aspiration detection by breath and swallowing sound analysis.

    PubMed

    Sarraf Shirazi, Samaneh; Moussavi, Zahra

    2012-01-01

    Detecting aspiration after swallows (the entry of bolus into trachea) is often a difficult task particularly when the patient does not cough; those are called silent aspiration. In this study, the application of acoustical analysis in detecting silent aspiration is investigated. We recorded the swallowing and the breath sounds of 10 individuals with swallowing disorders, who demonstrated silent aspiration during the fiberoptic endoscopic evaluation of swallowing (FEES) assessment. We analyzed the power spectral density (PSD) of the breath sound signals following each swallow; the PSD showed higher magnitude at low frequencies for the breath sounds following an aspiration. Therefore, we divided the frequency range below 300 Hz into 3 sub-bands, over which we calculated the average power as the characteristic features for the classification purpose. Then, the fuzzy k-means unsupervised classification method was deployed to find the two clusters in the data set: the aspirated and non-aspirated groups. The results were evaluated using the FEES assessments provided by the speech language pathologists. The results show 82.3% accuracy in detecting swallows with silent aspiration. Although the proposed method should be verified on a larger dataset, the results are promising for the use of acoustical analysis as a clinical tool to detect silent aspiration.

  13. Role of aspiration-induced migration in cooperation.

    PubMed

    Yang, Han-Xin; Wu, Zhi-Xi; Wang, Bing-Hong

    2010-06-01

    Both cooperation and migration are ubiquitous in human society and animal world. In this Rapid Communication, we propose an aspiration-induced migration in which individuals will migrate to new sites provided that their payoffs are below some aspiration level. It is found that moderate aspiration level can best favor cooperative behavior. In particular, moderate aspiration level enables cooperator clusters to maintain and expand whereas induces defector clusters to disintegrate, thus promoting the diffusion of cooperation among population. Our results provide insights into understanding the role played by migration in the emergence of cooperative behavior.

  14. Oropharyngeal dysphagia and aspiration in patients with ataxia-telangiectasia.

    PubMed

    Lefton-Greif, M A; Crawford, T O; Winkelstein, J A; Loughlin, G M; Koerner, C B; Zahurak, M; Lederman, H M

    2000-02-01

    To determine whether patients with ataxia-telangiectasia exhibit oropharyngeal dysphagia with concomitant aspiration and to examine the relationships among swallowing function, age, and nutritional status. Seventy patients (mean age, 10.7 years; range, 1.8 to 30 years) had feeding/swallowing and nutritional evaluations. Fifty-one patients, in whom there were concerns about swallowing safety, were examined with a standardized videofluoroscopic swallow study. Fourteen of the 51 patients (27%) with histories suggestive of dysphagia demonstrated aspiration. Of these, silent aspiration (aspiration without a cough) occurred in 10 (71%) patients. Aspirators were significantly older than non-aspirators (mean age, 16.9 vs 10.8 years; P =.002). Advancing age was the strongest factor associated with aspiration during continuous drinking (P =.01). In patients with ataxia-telangiectasia, weight and weight/height were abnormally low at all ages and most compromised in older patients. Patients who aspirated had significantly lower mean weight (P <.002) and weight/height z scores (P <.001) than did patients who did not aspirate. Oropharyngeal dysphagia is common and appears to be progressive in patients with ataxia-telangiectasia. Older patients also have a higher incidence of poorer nutritional status. The relationship between dysphagia and nutritional status deserves further investigation.

  15. Silent aspiration: results of 2,000 video fluoroscopic evaluations.

    PubMed

    Garon, Bernard R; Sierzant, Tess; Ormiston, Charles

    2009-08-01

    The purpose of this retrospective study of aspiration and the lack of a protective cough reflex at the vocal folds (silent aspiration) was to increase the awareness of nursing staffs of the diagnostic pathology groups associated with silent aspiration. Of the 2,000 patients evaluated in this study, 51% aspirated on the video fluoroscopic evaluation. Of the patients who aspirated, 55% had no protective cough reflex (silent aspiration). The diagnostic pathology groups with the highest rates of silent aspiration were brain cancer, brainstem stroke, head-neck cancer, pneumonia, dementia/Alzheimer, chronic obstructive lung disease, seizures, myocardial infarcts, neurodegenerative pathologies, right hemisphere stroke, closed head injury, and left hemisphere stroke. It is of high concern that the diagnostic groups identified in this research as having the highest risk of silent aspiration be viewed as "red-flag" patients by the nursing staff caring for them. Early nursing dysphagia screens, with close attention to the clinical symptoms associated with silent aspiration, and early referral for formal dysphagia evaluation are stressed.

  16. [An Overview of Incidence and Outcome of Perioperative Pulmonary Aspiration].

    PubMed

    Nakazawa, Koichi; Shinoda, Ken

    2016-01-01

    Examination of the literature suggests that the incidence of aspiration pneumonia in the perioperative period is relatively infrequent. Since Mendelson's report of aspiration pneumonitis in 1946, the factors that contribute to the likelihood of aspiration have been identified, and numerous attempts for preventions for regurgitation or pulmonary aspiration have been made. The low incidence of major morbidity of anesthesia-related pulmonary aspiration may be due to adopting quality measures, applying practice guidelines for preoperative fasting, and the use of pharmacologic agents to reduce the risk of pulmonary aspiration. More systematic preoperative checking and more careful selection of patients are necessary when a supraglottic airway is used in preference to a tracheal tube. Second generation supraglottic airways may not reduce the risk of regurgitation, but may reduce the chance of aspiration if the mask position is correct and drain tube works well. Because the mortality and morbidity of aspiration pneumonia remain relatively high, the preoperative risk evaluation is very important to avoid regurgitation or aspiration.

  17. Organization of the connections between claustrum and cortex in the mouse

    PubMed Central

    Wang, Quanxin; Ng, Lydia; Harris, Julie A.; Feng, David; Li, Yang; Royall, Josh J.; Oh, Seung Wook; Bernard, Amy; Sunkin, Susan M.; Koch, Christof

    2016-01-01

    ABSTRACT The connections between the claustrum and the cortex in mouse are systematically investigated with adeno‐associated virus (AAV), an anterograde viral tracer. We first define the boundary and the three‐dimensional structure of the claustrum based on a variety of molecular and anatomical data. From AAV injections into 42 neocortical and allocortical areas, we conclude that most cortical areas send bilateral projections to the claustrum, the majority being denser on the ipsilateral side. This includes prelimbic, infralimbic, medial, ventrolateral and lateral orbital, ventral retrosplenial, dorsal and posterior agranular insular, visceral, temporal association, dorsal and ventral auditory, ectorhinal, perirhinal, lateral entorhinal, and anteromedial, posteromedial, lateroposterior, laterointermediate, and postrhinal visual areas. In contrast, the cingulate and the secondary motor areas send denser projections to the contralateral claustrum than to the ipsilateral one. The gustatory, primary auditory, primary visual, rostrolateral visual, and medial entorhinal cortices send projections only to the ipsilateral claustrum. Primary motor, primary somatosensory and subicular areas barely send projections to either ipsi‐ or contralateral claustrum. Corticoclaustral projections are organized in a rough topographic manner, with variable projection strengths. We find that the claustrum, in turn, sends widespread projections preferentially to ipsilateral cortical areas with different projection strengths and laminar distribution patterns and to certain contralateral cortical areas. Our quantitative results show that the claustrum has strong reciprocal and bilateral connections with prefrontal and cingulate areas as well as strong reciprocal connections with the ipsilateral temporal and retrohippocampal areas, suggesting that it may play a crucial role in a variety of cognitive processes. J. Comp. Neurol. 525:1317–1346, 2017. © 2016 Wiley Periodicals, Inc. PMID

  18. Aspirations langagieres: Negociation et apprentissage du francais (Language Aspirations: Negotiation and Learning French).

    ERIC Educational Resources Information Center

    Lepetit, Daniel; Cichocki, Wladyslaw

    1990-01-01

    A survey of 130 beginning French students at the University of Windsor (Canada) focused on their second language aspirations, expectations, and anticipated needs. Interpersonal relations appear to be the primary motivator, with travel and instrumental motivation secondary. (20 references) (Author/MSE)

  19. Osteogenic potential of reamer irrigator aspirator (RIA) aspirate collected from patients undergoing hip arthroplasty.

    PubMed

    Porter, Ryan M; Liu, Fangjun; Pilapil, Carmencita; Betz, Oliver B; Vrahas, Mark S; Harris, Mitchel B; Evans, Christopher H

    2009-01-01

    Intramedullary nailing preceded by canal reaming is the current standard of treatment for long-bone fractures requiring stabilization. However, conventional reaming methods can elevate intramedullary temperature and pressure, potentially resulting in necrotic bone, systemic embolism, and pulmonary complications. To address this problem, a reamer irrigator aspirator (RIA) has been developed that combines irrigation and suction for reduced-pressure reaming with temperature modulation. Osseous particles aspirated by the RIA can be recovered by filtration for use as an autograft, but the flow-through is typically discarded. The purpose of this study was to assess whether this discarded filtrate has osteogenic properties that could be used to enhance the total repair potential of aspirate. RIA aspirate was collected from five patients (ages 71-78) undergoing hip hemiarthroplasty. Osseous particles were removed using an open-pore filter, and the resulting filtrate (230 +/- 200 mL) was processed by Ficoll-gradient centrifugation to isolate mononuclear cells (6.2 +/- 5.2 x 10(6) cells/mL). The aqueous supernatant contained FGF-2, IGF-I, and latent TGF-beta1, but BMP-2 was below the limit of detection. The cell fraction included culture plastic-adherent, fibroblastic cells that displayed a surface marker profile indicative of mesenchymal stem cells and that could be induced along the osteogenic, adipogenic, and chondrogenic lineages in vitro. When compared to outgrowth cells from the culture of osseous particles, filtrate cells were more sensitive to seeding density during osteogenic culture but had similar capacity for chondrogenesis. These results suggest using RIA aspirate to develop improved, clinically expeditious, cost-effective technologies for accelerating the healing of bone and other musculoskeletal tissues.

  20. Osteogenic Potential of Reamer Irrigator Aspirator (RIA) Aspirate Collected from Patients Undergoing Hip Arthroplasty

    PubMed Central

    Porter, Ryan M.; Liu, Fangjun; Pilapil, Carmencita; Betz, Oliver B.; Vrahas, Mark S.; Harris, Mitchel B.; Evans, Christopher H.

    2009-01-01

    Intramedullary nailing preceded by canal reaming is the current standard of treatment for long-bone fractures requiring stabilization. However, conventional reaming methods can elevate intramedullary temperature and pressure, potentially resulting in necrotic bone, systemic embolism, and pulmonary complications. To address this problem, a reamer irrigator aspirator (RIA) has been developed that combines irrigation and suction for reduced-pressure reaming with temperature modulation. Osseous particles aspirated by the RIA can be recovered by filtration for use as an autograft, but the flow-through is typically discarded. The purpose of this study was to assess whether this discarded filtrate has osteogenic properties that could be used to enhance the total repair potential of aspirate. RIA aspirate was collected from five patients (ages 71–78) undergoing hip hemiarthroplasty. Osseous particles were removed using an open-pore filter, and the resulting filtrate (230 ± 200 mL) was processed by Ficoll-gradient centrifugation to isolate mononuclear cells (6.2 ± 5.2 × 106 cells/mL). The aqueous supernatant contained FGF-2, IGF-I, and latent TGF-β1, but BMP-2 was below the limit of detection. The cell fraction included culture plastic-adherent, fibroblastic cells that displayed a surface marker profile indicative of mesenchymal stem cells and that could be induced along the osteogenic, adipogenic, and chondrogenic lineages in vitro. When compared to outgrowth cells from the culture of osseous particles, filtrate cells were more sensitive to seeding density during osteogenic culture but had similar capacity for chondrogenesis. These results suggest using RIA aspirate to develop improved, clinically expeditious, cost-effective technologies for accelerating the healing of bone and other musculoskeletal tissues. PMID:18655129

  1. CX-516 Cortex pharmaceuticals.

    PubMed

    Danysz, Wojciech

    2002-07-01

    CX-516 is one of a series of AMPA modulators under development by Cortex, in collaboration with Shire and Servier, for the potential treatment of Alzheimer's disease (AD), schizophrenia and mild cognitive impairment (MCI) [234221]. By June 2001, CX-516 was in phase II trials for both schizophrenia and attention deficit hyperactivity disorder (ADHD) [412513]. A phase II trial in fragile X syndrome and autism was expected to start in May 2002 [449861]. In October 2001, Cortex was awarded a Phase II SBIR grant of $769,818 from the National Institutes of Mental Health to investigate the therapeutic potential of AMPAkines in schizophrenia. This award was to support a phase IIb study of CX-516 as a combination therapy in schizophrenia patients concomitantly treated with olanzapine. The trial was to enroll 80 patients and employ a randomized, double-blind, placebo-controlled design in which the placebo group was to receive olanzapine plus placebo and the active group was to receive olanzapine plus CX-516 [425982]. In April 2000, Shire and Cortex signed an option agreement in which Shire was to evaluate CX-516for the treatment of ADHD. Under the terms of the agreement, Shire would undertake a double-blind, placebo-controlled evaluation of CX-516 involving ADHD patients. If the study proved effective, Shire would have the right to convert its option into an exclusive worldwide license for the AMPAkines for ADHD under a development and licensing agreement. Should Shire elect to execute this agreement, Shire would bear all future developmental costs [363618]. By February 2002, Cortex and Servier had revealed their intention to begin enrolment for an international study of an AMPAkine compound as a potential treatment for MCI in the near future. Assuming enrollment proceeded as anticipated, results were expected during the second quarter of 2003 [439301]. By May 2002, phase II trials were underway [450134]. In March 2002, Cortex was awarded extended funding under the

  2. Neuropeptide S facilitates mice olfactory function through activation of cognate receptor-expressing neurons in the olfactory cortex.

    PubMed

    Shao, Yu-Feng; Zhao, Peng; Dong, Chao-Yu; Li, Jing; Kong, Xiang-Pan; Wang, Hai-Liang; Dai, Li-Rong; Hou, Yi-Ping

    2013-01-01

    Neuropeptide S (NPS) is a newly identified neuromodulator located in the brainstem and regulates various biological functions by selectively activating the NPS receptors (NPSR). High level expression of NPSR mRNA in the olfactory cortex suggests that NPS-NPSR system might be involved in the regulation of olfactory function. The present study was undertaken to investigate the effects of intracerebroventricular (i.c.v.) injection of NPS or co-injection of NPSR antagonist on the olfactory behaviors, food intake, and c-Fos expression in olfactory cortex in mice. In addition, dual-immunofluorescence was employed to identify NPS-induced Fos immunereactive (-ir) neurons that also bear NPSR. NPS (0.1-1 nmol) i.c.v. injection significantly reduced the latency to find the buried food, and increased olfactory differentiation of different odors and the total sniffing time spent in olfactory habituation/dishabituation tasks. NPS facilitated olfactory ability most at the dose of 0.5 nmol, which could be blocked by co-injection of 40 nmol NPSR antagonist [D-Val(5)]NPS. NPS administration dose-dependently inhibited food intake in fasted mice. Ex-vivo c-Fos and NPSR immunohistochemistry in the olfactory cortex revealed that, as compared with vehicle-treated mice, NPS markedly enhanced c-Fos expression in the anterior olfactory nucleus (AON), piriform cortex (Pir), ventral tenia tecta (VTT), the anterior cortical amygdaloid nucleus (ACo) and lateral entorhinal cortex (LEnt). The percentage of Fos-ir neurons that also express NPSR were 88.5% and 98.1% in the AON and Pir, respectively. The present findings demonstrated that NPS, via selective activation of the neurons bearing NPSR in the olfactory cortex, facilitates olfactory function in mice.

  3. Emergent intrathecal baclofen withdrawal after pseudomeningocele aspiration.

    PubMed

    Smith, Timothy R; Mithal, Divakar S; Park, Anne; Bohnen, Angela; Adel, Joseph; Rosenow, Joshua M

    2013-01-01

    Intrathecal baclofen (ITB) infusion has become a common treatment for severe spasticity. Many complications of these drug delivery systems have been reported such as those related to improper dosing, mechanical failure of the implanted pump or catheter, or post-operative wound issues. We report a case of ITB withdrawal after pseudomeningocele aspiration. A 21 year-old male with spastic quadriparesis due to traumatic brian injury (TBI) presented with a pseudomeningocele surrounding an ITB pump (215 mcg/day, continuous) implanted in the abdomen. The pseudomeningocele was percutaneously aspirated and approximately 15 hours later the patient developed signs and symptoms of acute baclofen withdrawal. As a result, the patient underwent an exploration of the ITB infusion system with an intraoperative epidural blood patch. The symptoms of ITB withdrawal improved over the next 18 hours. The subcutaneous cerebrospinal fluid (CSF) collection partially recurred 48 hours later, but this resolved after a second epidural blood patch. The case illustrates a unique presentation of a serious complication of ITB infusion. This underscores that timely diagnosis and treatment of acute baclofen withdrawal is key to optimal outcomes.

  4. Femoral bone marrow aspiration in live mice.

    PubMed

    Chung, Young Rock; Kim, Eunhee; Abdel-Wahab, Omar

    2014-07-05

    Serial sampling of the cellular composition of bone marrow (BM) is a routine procedure critical to clinical hematology. This protocol describes a detailed step-by-step technical procedure for an analogous procedure in live mice which allows for serial characterization of cells present in the BM. This procedure facilitates studies aimed to detect the presence of exogenously administered cells within the BM of mice as would be done in xenograft studies for instance. Moreover, this procedure allows for the retrieval and characterization of cells enriched in the BM such as hematopoietic stem and progenitor cells (HSPCs) without sacrifice of mice. Given that the cellular composition of peripheral blood is not necessarily reflective of proportions and types of stem and progenitor cells present in the marrow, procedures which provide access to this compartment without requiring termination of the mice are very helpful. The use of femoral bone marrow aspiration is illustrated here for cytological analysis of marrow cells, flow cytometric characterization of the hematopoietic stem/progenitor compartment, and culture of sorted HSPCs obtained by femoral BM aspiration compared with conventional marrow harvest.

  5. Semi-Supervised Learning of Cartesian Factors: A Top-Down Model of the Entorhinal Hippocampal Complex

    PubMed Central

    Lőrincz, András; Sárkány, András

    2017-01-01

    The existence of place cells (PCs), grid cells (GCs), border cells (BCs), and head direction cells (HCs) as well as the dependencies between them have been enigmatic. We make an effort to explain their nature by introducing the concept of Cartesian Factors. These factors have specific properties: (i) they assume and complement each other, like direction and position and (ii) they have localized discrete representations with predictive attractors enabling implicit metric-like computations. In our model, HCs make the distributed and local representation of direction. Predictive attractor dynamics on that network forms the Cartesian Factor “direction.” We embed these HCs and idiothetic visual information into a semi-supervised sparse autoencoding comparator structure that compresses its inputs and learns PCs, the distributed local and direction independent (allothetic) representation of the Cartesian Factor of global space. We use a supervised, information compressing predictive algorithm and form direction sensitive (oriented) GCs from the learned PCs by means of an attractor-like algorithm. Since the algorithm can continue the grid structure beyond the region of the PCs, i.e., beyond its learning domain, thus the GCs and the PCs together form our metric-like Cartesian Factors of space. We also stipulate that the same algorithm can produce BCs. Our algorithm applies (a) a bag representation that models the “what system” and (b) magnitude ordered place cell activities that model either the integrate-and-fire mechanism, or theta phase precession, or both. We relate the components of the algorithm to the entorhinal-hippocampal complex and to its working. The algorithm requires both spatial and lifetime sparsification that may gain support from the two-stage memory formation of this complex. PMID:28270783

  6. Semi-Supervised Learning of Cartesian Factors: A Top-Down Model of the Entorhinal Hippocampal Complex.

    PubMed

    Lőrincz, András; Sárkány, András

    2017-01-01

    The existence of place cells (PCs), grid cells (GCs), border cells (BCs), and head direction cells (HCs) as well as the dependencies between them have been enigmatic. We make an effort to explain their nature by introducing the concept of Cartesian Factors. These factors have specific properties: (i) they assume and complement each other, like direction and position and (ii) they have localized discrete representations with predictive attractors enabling implicit metric-like computations. In our model, HCs make the distributed and local representation of direction. Predictive attractor dynamics on that network forms the Cartesian Factor "direction." We embed these HCs and idiothetic visual information into a semi-supervised sparse autoencoding comparator structure that compresses its inputs and learns PCs, the distributed local and direction independent (allothetic) representation of the Cartesian Factor of global space. We use a supervised, information compressing predictive algorithm and form direction sensitive (oriented) GCs from the learned PCs by means of an attractor-like algorithm. Since the algorithm can continue the grid structure beyond the region of the PCs, i.e., beyond its learning domain, thus the GCs and the PCs together form our metric-like Cartesian Factors of space. We also stipulate that the same algorithm can produce BCs. Our algorithm applies (a) a bag representation that models the "what system" and (b) magnitude ordered place cell activities that model either the integrate-and-fire mechanism, or theta phase precession, or both. We relate the components of the algorithm to the entorhinal-hippocampal complex and to its working. The algorithm requires both spatial and lifetime sparsification that may gain support from the two-stage memory formation of this complex.

  7. Videofluoroscopic Predictors of Penetration-Aspiration in Parkinson's Disease Patients.

    PubMed

    Argolo, Natalie; Sampaio, Marília; Pinho, Patrícia; Melo, Ailton; Nóbrega, Ana Caline

    2015-12-01

    Parkinson's disease (PD) patients show a high prevalence of swallowing disorders and tracheal aspiration of food. The videofluoroscopic study of swallowing (VFSS) allows clinicians to visualize the visuoperceptual and temporal parameters associated with swallowing disorders in an attempt to predict aspiration risk. However, this subject remains understudied in PD populations. Our aim was to identify the predictors of penetration-aspiration in PD patients using the VFSS. Consecutive patients were evaluated using VFSS with different consistencies and volumes of food. A speech-language pathologist measured the type of intra-oral bolus organization, loss of bolus control, bolus location at the initiation of the pharyngeal swallow, the presence of multiple swallows, piecemeal deglutition, bolus residue in the pharyngeal recesses and temporal measures. Scores ≥3 on the penetration-aspiration scale (PAS) indicated the occurrence of penetration-aspiration. Using logistic marginal regression, we found that residue in the vallecula, residue in the upper esophageal sphincter and piecemeal deglutition were associated with penetration-aspiration (odds ratio (OR) = 4.09, 2.87 and 3.83; P = 0.0040, 0.0071 and 0.0009, respectively). Penetration/aspiration occurred only with fluids (both of thin and thick consistency), and no significant differences were observed between fluid types or food volumes. The mechanisms underlying dysphagia and penetration/aspiration in PD patients and indications for further studies are discussed.

  8. Students' Aspirations, Expectations and School Achievement: What Really Matters?

    ERIC Educational Resources Information Center

    Khattab, Nabil

    2015-01-01

    Using the Longitudinal Study of Young People in England (LSYPE), this study examines how different combinations of aspirations, expectations and school achievement can influence students' future educational behaviour (applying to university at the age of 17-18). The study shows that students with either high aspirations or high expectations have…

  9. Predictive Value and Psychological Meaning of Vocational Aspirations

    ERIC Educational Resources Information Center

    Holland, John L.; Gottfredson, Gary D.

    1975-01-01

    The psychological meaning and predictive value of a person's vocational aspirations were examined by applying Holland's typology to the vocational aspirations of high school juniors (N=140), and a second sample of college students studied over a one-year interval (N-624). (Author)

  10. Rural Aspirations, Rural Futures: From "Problem" to Possibility

    ERIC Educational Resources Information Center

    Tieken, Mara Casey; San Antonio, Donna M.

    2016-01-01

    Young people aspire, make choices, and develop within a particular place and historical context. Recently, federal and state governments, policy and research institutes, and advocacy organizations have shown a growing interest in the aspirations and transitions of rural youth--and, in particular, the role that schools play in shaping and…

  11. The Aspiration-Attainment Gap: Black Students and Education

    ERIC Educational Resources Information Center

    Buttaro, Anthony, Jr.; Battle, Juan; Pastrana, Antonio, Jr.

    2010-01-01

    Using a nationally representative sample from two waves of the National Educational Longitudinal Study (NELS), this research examines the aspiration-attainment gap that exists for Black students (N = 823). This gap is a measure of the difference between the educational level students said they aspired to reach reported in 1988 when attending 8th…

  12. Stability of Career Aspirations: A Longitudinal Test of Gottfredson's Theory

    ERIC Educational Resources Information Center

    Junk, Kate E.; Armstrong, Patrick Ian

    2010-01-01

    Gottfredson's theory of the career compromise process was evaluated using a longitudinal data set of 2,353 female and 321 male students recruited for Zuckerman's "Seven College Study," who reported their career aspirations twice over a 1-year period. Expressed career aspirations were coded on the dimensions of sex type, prestige, and the…

  13. Cold Antimatter Plasmas, and Aspirations for Cold Antihydrogen

    DTIC Science & Technology

    2002-06-24

    UNCLASSIFIED Defense Technical Information Center Compilation Part Notice ADP012494 TITLE: Cold Antimatter Plasmas, and Aspirations for Cold...part numbers comprise the compilation report: ADP012489 thru ADP012577 UNCLASSIFIED Cold Antimatter Plasmas, and Aspirations for Cold Antihydrogen G...and positrons. The antiprotons come initially from the new Antiproton Decel- erator facility at CERN. Good control of such cold antimatter plasmas is

  14. Life Aspirations, Values and Moral Foundations in Mongolian Youth

    ERIC Educational Resources Information Center

    Bespalov, Alexander; Prudnikova, Marina; Nyamdorj, Bavuu; Vlasov, Mikhail

    2017-01-01

    Life aspirations have aroused much interest in youth studies. Yet, their psychological correlates remain unclear, especially in countries outside the US. The aim of this study was to explore associations among aspirations, values and moral foundations in 157 Mongolian youth, through questionnaires used widely around the world. Correlational and…

  15. An Analysis of Taiwanese Aboriginal Students' Educational Aspirations

    ERIC Educational Resources Information Center

    Hou, Hsiao-I; Huang, Chia-Kai

    2012-01-01

    By analysing the national data from the Junior Survey of the Taiwan Higher Education Dataset, this study identified significant variables influencing the educational aspirations of aboriginal students at technical and vocational institutions. The study shows that several variables are predictive of the educational aspirations of aboriginal…

  16. Students' Aspirations, Expectations and School Achievement: What Really Matters?

    ERIC Educational Resources Information Center

    Khattab, Nabil

    2015-01-01

    Using the Longitudinal Study of Young People in England (LSYPE), this study examines how different combinations of aspirations, expectations and school achievement can influence students' future educational behaviour (applying to university at the age of 17-18). The study shows that students with either high aspirations or high expectations have…

  17. Mortality, morbidity, and disease severity of patients with aspiration pneumonia

    PubMed Central

    Lanspa, Michael J.; Jones, Barbara E.; Brown, Samuel M.; Dean, Nathan C.

    2013-01-01

    Background Aspiration pneumonia is a common syndrome, although less well characterized than other pneumonia syndromes. We describe a large population of patients with aspiration pneumonia. Methods In this retrospective population study, we queried the electronic medical record at a tertiary-care, university-affiliated hospital from 1996–2006. Patients were initially identified by ICD-9 code 507.x; subsequent physician chart review excluded patients with aspiration pneumonitis and those without a confirmatory radiograph. Patients with community-acquired aspiration pneumonia were compared to a contemporaneous population of community-acquired pneumonia (CAP) patients. We compared CURB-65 predicted mortality with actual 30-day mortality. Results We identified 628 patients with aspiration pneumonia, of which 510 were community-acquired. Median age was 77, with 30-day mortality of 21%. Compared to CAP patients, patients with community-acquired aspiration pneumonia had more frequent inpatient admission (99% vs. 58%) and ICU admission (38% vs. 14%), higher Charlson comorbidity index (3 vs. 1), and higher prevalence of “do not resuscitate/intubate” orders (24% vs. 11%). CURB-65 predicted mortality poorly in aspiration pneumonia patients (AUC 0.66). Conclusions Patients with community-acquired aspiration pneumonia are older, have more comorbidities, and demonstrate higher mortality than CAP patients, even after adjustment for age and comorbidities. CURB-65 poorly predicts mortality in this population. PMID:23184866

  18. Educational and Occupational Aspirations of High School Students.

    ERIC Educational Resources Information Center

    McNerney, Kristine A.; Coleman, Christy L.

    Shifts in the number of women in the workplace and a greater diversity and prestige level in their work may have an impact on the educational and occupational level to which students aspire. To examine the consequences of this shift, a comparison of the educational and occupational aspirations of high school students with the educational and…

  19. 21 CFR 886.4150 - Vitreous aspiration and cutting instrument.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Vitreous aspiration and cutting instrument. 886.4150 Section 886.4150 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... cutting instrument. (a) Identification. A vitreous aspiration and cutting instrument is an electrically...

  20. 21 CFR 886.4150 - Vitreous aspiration and cutting instrument.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Vitreous aspiration and cutting instrument. 886.4150 Section 886.4150 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... cutting instrument. (a) Identification. A vitreous aspiration and cutting instrument is an electrically...

  1. 21 CFR 886.4150 - Vitreous aspiration and cutting instrument.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Vitreous aspiration and cutting instrument. 886.4150 Section 886.4150 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... cutting instrument. (a) Identification. A vitreous aspiration and cutting instrument is an electrically...

  2. 21 CFR 886.4150 - Vitreous aspiration and cutting instrument.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Vitreous aspiration and cutting instrument. 886.4150 Section 886.4150 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... cutting instrument. (a) Identification. A vitreous aspiration and cutting instrument is an electrically...

  3. 21 CFR 886.4150 - Vitreous aspiration and cutting instrument.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Vitreous aspiration and cutting instrument. 886.4150 Section 886.4150 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... cutting instrument. (a) Identification. A vitreous aspiration and cutting instrument is an electrically...

  4. Factors Influencing the Vocational Aspirations of Victorian Year 9 Students.

    ERIC Educational Resources Information Center

    Schrom, Linda K.

    A study was conducted to determine the influence of family background and attitudinal factors on occupational aspirations of Year 9 students in Victoria, Australia. A survey was made of all Victorian Year 9 students and comparisons were made between groups of students who aspired to different occupations. Discriminant function analyses were…

  5. Factors Related to Postgraduate Educational Aspirations of Women College Graduates.

    ERIC Educational Resources Information Center

    de Wolf, Virginia A.

    This study compared 105 women university baccalaureates intending graduate study the year following graduation with women graduates matched by age and major who did not intend such study. Aspirers had significantly higher GPAs than non-aspirers, were more satisfied with their undergraduate major, had more often selected their major as preparation…

  6. Occupational Aspirations of State FFA Contest and Award Winners.

    ERIC Educational Resources Information Center

    Bowen, Blannie E.; Doerfert, David L.

    1989-01-01

    A study explored the occupational aspirations of 300 (of 503) students with high levels of participation in Future Farmers of America's (FFA) Computers in Agriculture (CIA), Proficiency Award (PA), and Prepared and Extemporaneous Speaking (PES) contests. CIA and PES winners aspired to professional occupations more than PA winners. PES winners…

  7. Career Aspirations of Women in the 20th Century

    ERIC Educational Resources Information Center

    Domenico, Desirae M.; Jones, Karen H.

    2006-01-01

    Women have increasingly become more involved in the workforce following World War II. Paid employment of women has shifted from primarily traditional female-oriented jobs to more non-traditional, and previously male-oriented careers. Women's participation in the workforce has lead to the study of career aspirations of women. Career aspirations are…

  8. Performing Desires: The Dilemma of Aspirations and Educational Attainment

    ERIC Educational Resources Information Center

    St. Clair, Ralf; Benjamin, Amanda

    2011-01-01

    The authors critique the mechanistic notion of aspirations running through much research and policy-making on educational and vocational outcomes. They present a performative model, with individuals drawing on limited social resources to express aspirations within constrained contexts. This argument is illustrated by discussion of the findings of…

  9. Rural Aspirations, Rural Futures: From "Problem" to Possibility

    ERIC Educational Resources Information Center

    Tieken, Mara Casey; San Antonio, Donna M.

    2016-01-01

    Young people aspire, make choices, and develop within a particular place and historical context. Recently, federal and state governments, policy and research institutes, and advocacy organizations have shown a growing interest in the aspirations and transitions of rural youth--and, in particular, the role that schools play in shaping and…

  10. The Relationship between Gender and Aspirations to Senior Management

    ERIC Educational Resources Information Center

    Litzky, Barrie; Greenhaus, Jeffrey

    2007-01-01

    Purpose: The purpose of this paper is to examine the relationship of gender, work factors, and non-work factors with aspirations to positions in senior management. A process model of senior management aspirations was developed and tested. Design/methodology/approach: Data were collected via an online survey that resulted in a sample of 368 working…

  11. Aspiration pneumonia. Pathophysiological aspects, prevention and management. A review.

    PubMed

    Petroianni, A; Ceccarelli, D; Conti, V; Terzano, C

    2006-12-01

    Aspiration pneumonias occur more frequently than reported and, in many cases, the disease is not recognised. In hospitalised and institutionalised patients with predisposing diseases prompt diagnosis of this complication and correct preventive measures can drastically reduce the worsening of clinical conditions and the deaths due to aspiration pneumonia. Normal airway structure, effective defence mechanisms, and preventive measures are decisive in reducing aspiration episodes. An increased aspiration risk for food, fluids, medications, or secretions may lead to the development of pneumonia. Pneumonia is the most common respiratory complication in all stroke deaths and in mechanical ventilation patients. In addition, the increased incidence of aspiration pneumonia with aging may be a consequence of impairment of swallowing and the cough reflex. Dysphagia, compromised consciousness, invasive procedures, anaesthesia, insufficient oral care, sleep disorders, and vomiting are all risk factors. Aspiration pneumonia includes different characteristic syndromes based on the amount (massive, acute, chronic) and physical character of the aspirated material (acid, infected, lipoid), needing a different therapeutic approach. Chronic patients education and correct health care practices are the keys for preventing the events of aspiration. In patients at risk a clinical and instrumental assessment of dysphagia should be evaluated. Management includes the removal of etiologic factors (drugs, tubes, mobilisation, oral hygiene), supportive care, and in bacterial pneumonias a specific antibiotic therapy for community-acquired or nosocomial events.

  12. A new portable aspirator for culicidae and other winged insects.

    PubMed

    Governatori, M; Bulgarini, C; Rivasi, F; Pampiglione, S

    1993-12-01

    A new type of portable aspirator is described. The aspirator uses as a suction device a fan that normally cools computers, in conjunction with other structural elements especially designed to cope with the greater suction power available. The device proved to be efficient, strong, light, easy to use, and silent.

  13. Sociological Theory and Youth Aspiration Research: A Critical Overview.

    ERIC Educational Resources Information Center

    Picou, J. Steven; Wells, Richard H.

    Reviewing sociological theories relative to youth aspiration research, the following thesis was presented: "pre-path analysis aspiration research was characterized by a person-centered, middle-range functionalist approach which eventually shifted to a person-centered, functionalist-system approach with the introduction of the path model…

  14. Study of Educational Aspirations of Preparatory School Students in Yemen.

    ERIC Educational Resources Information Center

    Edington, Everett D.

    To identify causes for low enrollment in secondary agricultural schools in Yemen, the United States Agency for International Development and the Yemen Ministry of Education surveyed 990 preparatory (junior high) students, examining their educational aspirations, differences between rural and urban youth, major influences on student aspirations,…

  15. A tale of three aspirations: foreign bodies in the airway.

    PubMed

    Pritt, B; Harmon, M; Schwartz, M; Cooper, K

    2003-10-01

    Tracheobronchial foreign body aspiration is a serious medical problem, with clinical manifestations ranging from acute asphyxiation to insidious lung damage, as demonstrated by the three presented cases. Patient 1 aspirated during dinner, emergency bronchoscopy retrieved pieces of food, and she fully recovered the following day. Patient 2 presented with recurrent pneumonia and a right lower lobe lung abscess. After right lower lobectomy, pathology revealed a foreign object in the right main stem bronchus, a peanut aspirated one year earlier. Patient 3 became unresponsive several days after spinal surgery. The differential diagnosis included myocardial infarction, stroke, and foreign body aspiration. The patient died and necropsy revealed a foreign body in the right main stem bronchus (cooked meat). Thus, foreign body aspiration is not always suspected clinically, and the pathologist may play an important role in making the diagnosis. Histological identification of the aspirated material may be necessary for definitive diagnosis. Therefore, sections of commonly aspirated foods are presented, together with a 10 year history of aspirated objects received by this institution's surgical pathology department.

  16. Study of Educational Aspirations of Preparatory School Students in Yemen.

    ERIC Educational Resources Information Center

    Edington, Everett D.

    To identify causes for low enrollment in secondary agricultural schools in Yemen, the United States Agency for International Development and the Yemen Ministry of Education surveyed 990 preparatory (junior high) students, examining their educational aspirations, differences between rural and urban youth, major influences on student aspirations,…

  17. Calculating Student Aspiration: Bourdieu, Spatiality and the Politics of Recognition

    ERIC Educational Resources Information Center

    Gale, Trevor; Parker, Stephen

    2015-01-01

    This paper reports on a recent study of aspirations for higher education by secondary school students from disadvantaged backgrounds in regional Australia. At the same time, it goes in search of explanations that transcend a Bourdieuian account of aspirations as produced by and reproductive of cultural histories and dominance, given the apparent…

  18. Students' School Motivation and Aspiration over High School Years

    ERIC Educational Resources Information Center

    Yeung, Alexander Seeshing; McInerney, Dennis M.

    2005-01-01

    Students from a school in Hong Kong (n = 199) responded to 22 items asking about their school motivation and aspirations in a survey. Structural equation models found four school motivation factors consistent with the task, effort, competition, and praise scales of the Inventory of School Motivation, one education aspiration factor, one career…

  19. Connectivity Reveals Sources of Predictive Coding Signals in Early Visual Cortex During Processing of Visual Optic Flow.

    PubMed

    Schindler, Andreas; Bartels, Andreas

    2017-05-01

    Superimposed on the visual feed-forward pathway, feedback connections convey higher level information to cortical areas lower in the hierarchy. A prominent framework for these connections is the theory of predictive coding where high-level areas send stimulus interpretations to lower level areas that compare them with sensory input. Along these lines, a growing body of neuroimaging studies shows that predictable stimuli lead to reduced blood oxygen level-dependent (BOLD) responses compared with matched nonpredictable counterparts, especially in early visual cortex (EVC) including areas V1-V3. The sources of these modulatory feedback signals are largely unknown. Here, we re-examined the robust finding of relative BOLD suppression in EVC evident during processing of coherent compared with random motion. Using functional connectivity analysis, we show an optic flow-dependent increase of functional connectivity between BOLD suppressed EVC and a network of visual motion areas including MST, V3A, V6, the cingulate sulcus visual area (CSv), and precuneus (Pc). Connectivity decreased between EVC and 2 areas known to encode heading direction: entorhinal cortex (EC) and retrosplenial cortex (RSC). Our results provide first evidence that BOLD suppression in EVC for predictable stimuli is indeed mediated by specific high-level areas, in accord with the theory of predictive coding. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  20. Associative-memory representations emerge as shared spatial patterns of theta activity spanning the primate temporal cortex

    PubMed Central

    Nakahara, Kiyoshi; Adachi, Ken; Kawasaki, Keisuke; Matsuo, Takeshi; Sawahata, Hirohito; Majima, Kei; Takeda, Masaki; Sugiyama, Sayaka; Nakata, Ryota; Iijima, Atsuhiko; Tanigawa, Hisashi; Suzuki, Takafumi; Kamitani, Yukiyasu; Hasegawa, Isao

    2016-01-01

    Highly localized neuronal spikes in primate temporal cortex can encode associative memory; however, whether memory formation involves area-wide reorganization of ensemble activity, which often accompanies rhythmicity, or just local microcircuit-level plasticity, remains elusive. Using high-density electrocorticography, we capture local-field potentials spanning the monkey temporal lobes, and show that the visual pair-association (PA) memory is encoded in spatial patterns of theta activity in areas TE, 36, and, partially, in the parahippocampal cortex, but not in the entorhinal cortex. The theta patterns elicited by learned paired associates are distinct between pairs, but similar within pairs. This pattern similarity, emerging through novel PA learning, allows a machine-learning decoder trained on theta patterns elicited by a particular visual item to correctly predict the identity of those elicited by its paired associate. Our results suggest that the formation and sharing of widespread cortical theta patterns via learning-induced reorganization are involved in the mechanisms of associative memory representation. PMID:27282247

  1. Adrenal histoplasmosis: a diagnosis on fine needle aspiration cytology.

    PubMed

    Rana, Chanchal; Kumari, Niraj; Krishnani, Narendra

    2011-06-01

    Histoplasmosis is a fungal disease endemic in central and eastern states of United States, South America, Africa, and Asia. It may present as chronic pulmonary infection or in disseminated form of infection. The disseminated form of histoplasmosis frequently affects the adrenal gland and is more likely to affect immunocompromised patients as compared to immunocompetent individuals. There are very few cases of adrenal histoplasmosis diagnosed on fine needle aspiration cytology. In the present era when fine needle aspiration has become popular modality for diagnosis, adrenal fine needle aspiration is still a less commonly practiced technique. We report eight cases of adrenal histoplasmosis diagnosed on fine needle aspiration cytology in patients with bilateral adrenal masses. The present case series supports the role of fine needle aspiration cytology of adrenal gland infections where surgery can be prevented and a definitive diagnosis can be made on which treatment can be offered. Copyright © 2010 Wiley-Liss, Inc.

  2. Transrectal fine needle aspiration cytology of granulomatous prostatitis.

    PubMed

    Mondal, A; Mukherjee, B; Ghosh, E

    1994-07-01

    Transrectal fine needle aspiration cytology by Franzen technique was carried out from January, 1985 till January, 1992 on 567 patients having prostatomegaly which were suspicious of malignancy by clinical per rectal examination. Granulomatous prostatitis was diagnosed in 56 cases. Analysis showed 34 cases were tuberculous prostatitis and 22 cases were nonspecific granulomatous prostatitis. Comparison of aspiration cytology with bacteriological study of the aspirated material and histopathology showed correct diagnosis of granulomatous prostatitis by fine needle aspiration. The findings indicate that transrectal fine needle aspiration cytology is a reliable procedure for diagnosis of granulomatous prostatitis which can clinically mimic prostatic malignancy when it presents as a diffuse or nodular enlargement with firm to hard consistency.

  3. Aspiration lung disorders in bovines: a case report and review.

    PubMed

    Shakespeare, Anthony S

    2012-11-01

    Lung aspiration disorders in bovines are invariably diagnosed as infectious aspiration pneumonias. There is a distinct differentiation between aspiration pneumonia and aspiration pneumonitis in humans that can be applied to bovines. The nature and quantity of the aspirate can result in differing pathogeneses which can require differing therapeutic approaches. Whilst blood gases were important in detecting and prognosticating lung problems, changes in barometric pressure with altitude have to be considered when interpreting partial pressures of oxygen. Anatomical differences in the lungs of bovines can explain why this species is more prone to certain pneumonic problems. Pulmonary physiotherapy is important in treating lung disorders in humans and should be considered as an adjunct therapy in bovine respiratory conditions. A case work-up was used to highlight some of the points discussed in this article.

  4. The extremely low-frequency magnetic field exposure differently affects the AMPAR and NMDAR subunit expressions in the hippocampus, entorhinal cortex and prefrontal cortex without effects on the rat spatial learning and memory.

    PubMed

    Li, Chao; Xie, Meilan; Luo, Fenlan; He, Chao; Wang, Jiali; Tan, Gang; Hu, Zhian

    2014-10-01

    In the present study, we investigated the effects of chronic exposure (14 and 28 days) to a 50 Hz, 0.5 mT extremely low-frequency magnetic field (ELF-MF) on the NMDAR and AMPAR subunit expressions and rat spatial learning and memory. Using the Western blotting method, we found ELF-MF exposure specifically decreased the expressions of GluA2 in the EC post 28 day exposure and GluA3 of AMPAR subunits in the PFC after 14 day exposure, while it did not affect the AMPAR subunit expression in the hippocampus at both time points. As for NMDAR subunits, 14 day ELF-MF exposure significantly increased the levels of GluN2A and GluN2B in the hippocampus. Moreover, the levels of GluN1 and GluN2A were enhanced in the EC and PFC after two weeks of ELF-MF exposure. Interestingly, 28 day ELF-MF exposure induced a different expression pattern for NMDAR subunits. The increased GluN2A expression observed at 14 day post ELF-MF exposure was recovered after prolonged exposure in the hippocampus and PFC. In the EC, the increased expression of GluN1 achieved to control level and, specifically, a decrease in GluN2A level was observed. Surprisingly, neither 14 nor 28 day ELF-MF did affect the rat spatial reference memory as assessed by water maze. These results indicate that the dynamic and brain-region specific changes in ionotropic glutamate receptor expression induced by ELF-MF are insufficient to influence the rat spatial learning ability.

  5. CT Pulmonary Findings in Healthy Older Adult Aspirators versus Nonaspirators

    PubMed Central

    Butler, Susan G.; Clark, Hollins; Baginski, Scott G.; Todd, J. Tee; Lintzenich, Catherine; Leng, Xiaoyan

    2013-01-01

    Objectives/Hypothesis In previous studies, we consistently found that approximately 30% of asymptomatic healthy older adults silently aspirated liquids during a flexible endoscopic evaluation of swallowing (FEES), and that their aspiration status was stable for the following year. However, no studies have systematically evaluated effects of silent aspiration on lung parenchyma and airways. We used computed tomography (CT) to compare lungs of healthy older adult aspirators versus nonaspirators. We hypothesized that CT images would show pulmonary differences in healthy older adult aspirators versus nonaspirators. Study Design Prospective study. Methods Fifty healthy older adults (25 aspirators and 25 nonaspirators) who participated in a previous FEES were randomly selected. CT scans were performed; on inspiration, lung views were taken at 1.25 mm and 2.5 mm windows; on expiration, lung views were taken at 2.5 mm. CT scans were reviewed by radiologists blinded to group assignment. Outcomes included bronchiectasis, bronchiolectasis, bronchial wall thickening, parenchymal band, fibrosis, air trapping, intraluminal airway debris, and tree-in-bud pattern. Results Chi-square analyses between aspirators and nonaspirators found no statistically significant differences between aspirators and nonaspirators for any outcomes (p > 0.05). Logistic regression analyses adjusted for smoking did not change the results. Conclusion(s) There were no differences in pulmonary CT findings between healthy older adult aspirators and nonaspirators. This study adds to the evidence that some aspiration may be within the range of normal for older adults, or at least does not contribute to a change in pulmonary appearance on CT images. PMID:23832617

  6. Acid aspiration-induced airways hyperresponsiveness in mice

    PubMed Central

    Leclair, Timothy R.; von Reyn, Jessica; Larrabee, Yuna C.; Cloutier, Mary E.; Irvin, Charles G.; Bates, Jason H. T.

    2009-01-01

    The role of gastroesophageal reflux and micro-aspiration as a trigger of airways hyperresponsiveness (AHR) in patients with asthma is controversial. The role of acid reflux and aspiration as a direct cause of AHR in normal subjects is also unclear. We speculated that aspiration of a weak acid with a pH (1.8) equivalent to the upper range of typical gastric contents would lead to AHR in naive mice. We further speculated that modest reductions in aspirate acidity to a level expected during gastric acid suppression therapy (pH 4.0) would impede aspiration-induced AHR. BALB/c female mice were briefly anesthetized with isoflurane and allowed to aspirate 75 μl of saline with HCl (pH 1.8, 4.0, or 7.4) or underwent sham aspiration. Mice were re-anesthetized 2 or 24 h later, underwent tracheostomy, and were coupled to a mechanical ventilator. Forced oscillations were used to periodically measure respiratory impedance (Zrs) following aerosol delivery of saline and increasing doses of methacholine to measure for AHR. Values for elastance (H), airways resistance (RN), and tissue damping (G) were derived from Zrs. Aspirate pH of 1.8 led to a significant overall increase in peak RN, G, and H compared with pH 4.0 and 7.4 at 2 and 24 h. Differences between pH 7.4 and 4.0 were not significant. In mice aspirating pH 1.8 compared with controls, airway lavage fluid contained more neutrophils, higher protein, and demonstrated higher permeability. We conclude that acid aspiration triggers an acute AHR, driven principally by breakdown of epithelial barrier integrity within the airways. PMID:19797689

  7. Religiosity and Migration Aspirations among Mexican Youth.

    PubMed

    Hoffman, Steven; Marsiglia, Flavio Francisco; Ayers, Stephanie L

    2015-02-01

    International migration has become an important topic of discussion from a policy and humanitarian perspective. Part of the debate includes a renewed interest in understanding the factors that influence decisions about migration to the US among Mexican youth still residing in their country of origin. The purpose of this study was to advance knowledge specifically about internal and external religiosity and their influence on youths' migration aspirations. The data for this study were collected in 2007 from students enrolled in an alternative high school program located in the state of Guanajuato, Mexico. The findings indicated that as external religiosity increases, the desire to work or live in the USA decreases. Furthermore, as internal religiosity increases, the desire to work or live in the USA and plans to migrate increase. The results are interpreted and discussed in light of previous research on religious and cultural norm adherence.

  8. [Our experiences with early vacuum aspiration (miniinterruption)].

    PubMed

    Poradovský, K; Ondás, P; Posluch, J

    1982-07-01

    The authors report their experiences with 80 early vacuum aspirations (mini-interruptions) performed at the 1st Dept. of Gynecology and Obstetrics of the University Hospital in Kosice during 1980-81. The procedure was performed between days 36-42 in 15% of the women, between days 43-49 in 52.7% of the women, between days 50-56 in 27.5%, and between days 57-60 in 5% of the women. Interruption of pregnancy did not require general anesthesia or hospitalization of the patients. Complications occurred in 10% of the women, 6.25% due to residua and 2.5% to inflammation. Further experience should reduce the occurrence of complications. The authors consider the method to be advantageous and prospective. (author's modified)

  9. Complications of oropharyngeal dysphagia: aspiration pneumonia.

    PubMed

    Almirall, Jordi; Cabré, Mateu; Clavé, Pere

    2012-01-01

    The incidence and prevalence of aspiration pneumonia (AP) are poorly defined. They increase in direct relation with age and underlying diseases. The pathogenesis of AP presumes the contribution of risk factors that alter swallowing function and predispose to the oropharyngeal bacterial colonization. The microbial etiology of AP involves Staphylococcus aureus, Haemophilus influenzae and Streptococcus pneumoniae for community-acquired AP and Gram-negative aerobic bacilli in nosocomial pneumonia. It is worth bearing in mind the relative unimportance of anaerobic bacteria in AP. When we choose the empirical antibiotic treatment, we have to consider some pathogens identified in oropharyngeal flora. Empirical treatment with antianaerobics should only be used in certain patients. According to some known risks factors, the prevention of AP should include measures in order to avoid it.

  10. Fine needle aspiration cytology in fibromatosis

    PubMed Central

    Tanwar, Pranay; Gupta, Nalini; Vasishta, Rakesh Kumar; Singh, Gurpreet

    2012-01-01

    Fibromatosis form a spectrum of clinicopathologic entities characterized by the infiltrative proliferation of fibroblasts that lack malignant cytologic features. The fibromatosis can be localized or infiltrative and multicentric and can involve internal tissues and organs as the mesentery, retroperitoneum, breast, and almost every organ and region of the body, including the bones, the meninges and the central nervous system. We report a case of 37-year-old male who presented with a right supraclavicular mass with superficial infiltrative type of fibromatosis and fine needle aspiration cytology (FNAC) was performed. We report this case because of limited literature of FNAC in fibromatosis and quick role of FNAC in the diagnosis of fibromatosis. PMID:22438623

  11. Religiosity and Migration Aspirations among Mexican Youth

    PubMed Central

    Marsiglia, Flavio Francisco; Ayers, Stephanie L.

    2014-01-01

    International migration has become an important topic of discussion from a policy and humanitarian perspective. Part of the debate includes a renewed interest in understanding the factors that influence decisions about migration to the US among Mexican youth still residing in their country of origin. The purpose of this study was to advance knowledge specifically about internal and external religiosity and their influence on youths' migration aspirations. The data for this study were collected in 2007 from students enrolled in an alternative high school program located in the state of Guanajuato, Mexico. The findings indicated that as external religiosity increases, the desire to work or live in the USA decreases. Furthermore, as internal religiosity increases, the desire to work or live in the USA and plans to migrate increase. The results are interpreted and discussed in light of previous research on religious and cultural norm adherence. PMID:25663825

  12. Neurocontrol in sensory cortex

    NASA Astrophysics Data System (ADS)

    Ritt, Jason; Nandi, Anirban; Schroeder, Joseph; Ching, Shinung

    Technology to control neural ensembles is rapidly advancing, but many important challenges remain in applications, such as design of controls (e.g. stimulation patterns) with specificity comparable to natural sensory encoding. We use the rodent whisker tactile system as a model for active touch, in which sensory information is acquired in a closed loop between feedforward encoding of sensory information and feedback guidance of sensing motions. Motivated by this system, we present optimal control strategies that are tailored for underactuation (a large ratio of neurons or degrees of freedom to stimulation channels) and limited observability (absence of direct measurement of the system state), common in available stimulation technologies for freely behaving animals. Using a control framework, we have begun to elucidate the feedback effect of sensory cortex activity on sensing in behaving animals. For example, by optogenetically perturbing primary sensory cortex (SI) activity at varied timing relative to individual whisker motions, we find that SI modulates future sensing behavior within 15 msec, on a whisk by whisk basis, changing the flow of incoming sensory information based on past experience. J.T.R. and S.C. hold Career Awards at the Scientific Interface from the Burroughs Wellcome Fund.

  13. Sialorrhea and aspiration pneumonia: a case study.

    PubMed

    Trigoboff, Eileen; Grace, Jeffery; Szymanski, Herman; Bhullar, Jaspinder; Lee, Claudia; Watson, Thomas

    2013-05-01

    This case study compares two different clinical outcomes for a patient with a long-standing psychotic disorder prescribed clozapine on two occasions. During the first trial, clozapine was used at a higher dose for this patient (350-450mg/day) and included clinically significant sialorrhea, pneumonia, and pneumonia-like illnesses requiring immediate medical intervention including hospitalization. There were also patient complaints of fatigue, cough, choking, and constipation leading to poor adherence. Clozapine was discontinued when the patient withdrew his consent due to side effects, despite his awareness of its benefits, including reduction of command hallucinations and irritability. The second clozapine trial was associated with lower daily doses and therapeutic serum blood levels. The patient was actively participating in and adhering to the medication plan. A very narrow window of clozapine dose was exceeded for two days and the patient complained of hypersalivation, cough, and lethargy. He was subsequently hospitalized for a two week period to treat aspiration pneumonia. This hospitalization helped establish the ideal daily dose of clozapine for this patient and also brought the relationship between aspiration pneumonia and clozapine to the attention of the psychiatrist and medical specialist. Once the appropriate dosage for this patient was established, his psychotic and affective symptoms were controlled, he was not hampered by adverse side effects, and he started to actively participate in social and recreational activities and plans that culminated in discharge from a state psychiatric facility to a supportive community residence. It is our hope that the lessons we have learned from our shared experience with this patient will be of benefit to other clinicians and patients.

  14. Sialorrhea and Aspiration Pneumonia: A Case Study

    PubMed Central

    Grace, Jeffery; Szymanski, Herman; Bhullar, Jaspinder; Lee, Claudia; Watson, Thomas

    2013-01-01

    This case study compares two different clinical outcomes for a patient with a long-standing psychotic disorder prescribed clozapine on two occasions. During the first trial, clozapine was used at a higher dose for this patient (350-450mg/day) and included clinically significant sialorrhea, pneumonia, and pneumonia-like illnesses requiring immediate medical intervention including hospitalization. There were also patient complaints of fatigue, cough, choking, and constipation leading to poor adherence. Clozapine was discontinued when the patient withdrew his consent due to side effects, despite his awareness of its benefits, including reduction of command hallucinations and irritability. The second clozapine trial was associated with lower daily doses and therapeutic serum blood levels. The patient was actively participating in and adhering to the medication plan. A very narrow window of clozapine dose was exceeded for two days and the patient complained of hypersalivation, cough, and lethargy. He was subsequently hospitalized for a two week period to treat aspiration pneumonia. This hospitalization helped establish the ideal daily dose of clozapine for this patient and also brought the relationship between aspiration pneumonia and clozapine to the attention of the psychiatrist and medical specialist. Once the appropriate dosage for this patient was established, his psychotic and affective symptoms were controlled, he was not hampered by adverse side effects, and he started to actively participate in social and recreational activities and plans that culminated in discharge from a state psychiatric facility to a supportive community residence. It is our hope that the lessons we have learned from our shared experience with this patient will be of benefit to other clinicians and patients. PMID:23882437

  15. Preventing aspiration in the nursing home: the role of biofilm and data from the ICU.

    PubMed

    Drinka, Paul

    2010-01-01

    Two aspiration syndromes have been identified: Aspiration pneumonia is infectious caused by micro-aspiration of oral bacteria secondary to neurogenic dysphagia or sedation. Infectious bacteria may also be aspirated from the stomach. Aspiration pneumonitis classically follows large bolus aspiration of food, acid, or digestive enzymes and is initially noninfectious. Large bolus gastric aspiration events may have an acute/dramatic onset. This article discusses (1) prevention of recurrent aspiration events caused by 2 common motility disorders: neurogenic dysphagia and gastro esophageal reflux; (2) mechanical source control (debridement/drainage) of sites that may harbor large collections of bacteria protected from antibiotics in biofilm including dental plaque, coated tongue, and chronic sinusitis.

  16. The vomeronasal cortex - afferent and efferent projections of the posteromedial cortical nucleus of the amygdala in mice.

    PubMed

    Gutiérrez-Castellanos, Nicolás; Pardo-Bellver, Cecília; Martínez-García, Fernando; Lanuza, Enrique

    2014-01-01

    Most mammals possess a vomeronasal system that detects predominantly chemical signals of biological relevance. Vomeronasal information is relayed to the accessory olfactory bulb (AOB), whose unique cortical target is the posteromedial cortical nucleus of the amygdala. This cortical structure should therefore be considered the primary vomeronasal cortex. In the present work, we describe the afferent and efferent connections of the posteromedial cortical nucleus of the amygdala in female mice, using anterograde (biotinylated dextranamines) and retrograde (Fluorogold) tracers, and zinc selenite as a tracer specific for zinc-enriched (putative glutamatergic) projections. The results show that the posteromedial cortical nucleus of the amygdala is strongly interconnected not only with the rest of the vomeronasal system (AOB and its target structures in the amygdala), but also with the olfactory system (piriform cortex, olfactory-recipient nuclei of the amygdala and entorhinal cortex). Therefore, the posteromedial cortical nucleus of the amygdala probably integrates olfactory and vomeronasal information. In addition, the posteromedial cortical nucleus of the amygdala shows moderate interconnections with the associative (basomedial) amygdala and with the ventral hippocampus, which may be involved in emotional and spatial learning (respectively) induced by chemical signals. Finally, the posteromedial cortical nucleus of the amygdala gives rise to zinc-enriched projections to the ventrolateral septum and the ventromedial striatum (including the medial islands of Calleja). This pattern of intracortical connections (with the olfactory cortex and hippocampus, mainly) and cortico-striatal excitatory projections (with the olfactory tubercle and septum) is consistent with its proposed nature as the primary vomeronasal cortex. © 2013 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

  17. A new posterior iliac puncture/aspiration needle.

    PubMed

    Islam, Anwarul

    2016-03-25

    The needles that are currently used for obtaining bone marrow aspirate samples from the posterior ilium are typically those of 1930s vintage (eg, Klima, Salah or similar needles), which were specifically designed for sternal aspiration. These needles are not designed to obtain bone marrow aspirate samples from the posterior ilium and as a result they are unsatisfactory particularly if the patient is large or obese. A new posterior iliac puncture/aspiration needle has therefore been designed, which is particularly suited for bone marrow aspiration from the posterior ilium. The needle was tested on five cadavers and on five patients. The design and construction of the needle was found to be satisfactory and a marked improvement over the conventional sternal puncture needles particularly when large or obese patients were concerned. The new posterior iliac bone marrow aspiration needle has advantages that overcome the limitations of using a conventional sternal puncture needle to obtain marrow aspirates from the posterior ilium. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

  18. Word Recognition in Auditory Cortex

    ERIC Educational Resources Information Center

    DeWitt, Iain D. J.

    2013-01-01

    Although spoken word recognition is more fundamental to human communication than text recognition, knowledge of word-processing in auditory cortex is comparatively impoverished. This dissertation synthesizes current models of auditory cortex, models of cortical pattern recognition, models of single-word reading, results in phonetics and results in…

  19. Word Recognition in Auditory Cortex

    ERIC Educational Resources Information Center

    DeWitt, Iain D. J.

    2013-01-01

    Although spoken word recognition is more fundamental to human communication than text recognition, knowledge of word-processing in auditory cortex is comparatively impoverished. This dissertation synthesizes current models of auditory cortex, models of cortical pattern recognition, models of single-word reading, results in phonetics and results in…

  20. Novel Bedside Phonetic Evaluation to Identify Dysphagia and Aspiration Risk.

    PubMed

    Festic, Emir; Soto, Jose Soto; Pitre, Lisa A; Leveton, Marilu; Ramsey, Danielle M; Freeman, William D; Heckman, Michael G; Lee, Augustine S

    2016-03-01

    There is a need for improved clinical identification of hospitalized patients at risk of aspiration. We evaluated our novel phonetic test in a broad spectrum of patients at risk of aspiration in the ICU or intermediate care unit. We prospectively enrolled 60 hospitalized patients with aspiration risk, between December 2009 and September 2011, who subsequently underwent audio-recorded three-component phonetic bedside evaluation. The recordings were scored by two blinded speech-language pathologists. The institutional dysphagia admission screening test was performed by a bedside nurse. The primary outcomes, dysphagia and aspiration, were assessed by a videofluoroscopic swallowing study, fiber-optic endoscopic evaluation of swallowing, or both. We assessed the short- and long-term clinical outcomes (length of stay, subsequent aspiration pneumonia and respiratory failure, survival) and how these were associated with the phonetic and swallow assessments. Statistically significant linear associations with dysphagia were noted for all three individual phonetic components. Also, there were statistically significant linear associations with aspiration for diadochokinesis (P = .050) and consensus auditory-perceptual evaluation of voice (P = .025). Diadochokinesis alone predicted dysphagia (area under the curve [AUC], 0.74; P = .001) and aspiration (AUC, 0.67; P = .012). Its predictive ability improved when combined with normalized dysphagia admission screening test results (AUC, 0.79; P = .001). The short- and long-term clinical outcomes were adversely affected by the worse phonetic/swallowing scores, although they were not statistically different. Abnormal phonation among ICU and intermediate care unit patients is associated with dysphagia and aspiration. Future investigative efforts should uncover the most effective combination of evaluations for accurate bedside detection of dysphagia and aspiration risk in a broad spectrum of patients. Copyright © 2016 American College

  1. Adrenal cortex ontogenesis.

    PubMed

    Lalli, Enzo

    2010-12-01

    During the early phases of development, adrenal glands share a common origin with kidneys and gonads. The action of diverse transcription factors, signalling pathways and endocrine signals is required for the individualization of the adrenal primordium and its subsequent differentiation into an adult adrenal gland, with massive remodelling taking place around the time of birth in humans. Here I summarize the most important steps by which the adrenal cortex is shaped and present an overview of the current understanding of the genes and molecular pathways implicated in adrenal development and involved in the pathogenesis of its congenital diseases. Evidence is accumulating that some pivotal factors acting during adrenocortical development also play an important role to regulate the growth of adrenocortical tumors, representing promising therapeutical targets for a biology-oriented therapy. 2010 Elsevier Ltd. All rights reserved.

  2. Characterization and distribution of (125I)epidepride binding to dopamine D2 receptors in basal ganglia and cortex of human brain

    SciTech Connect

    Joyce, J.N.; Janowsky, A.; Neve, K.A. )

    1991-06-01

    The distribution and pharmacology of the binding of {sup 125}I-epidepride, a substituted benzamide with high affinity and selectivity for dopamine (DA) D2 receptors in rat brain is described in human brain. Saturation analysis of the binding of {sup 125}I-epidepride to membranes derived from striatum and regions of cortex demonstrated similar Kd values (34 and 28-33 pM, respectively) but differing maximum density of binding site values (152 and 3-8 fmol/mg of protein, respectively). The pharmacological profile of binding in cortex was also similar to striatum (epidepride greater than spiperone greater than butaclamol = flupenthixol greater than clozapine) except that an additional low-affinity site, blocked by the alpha-2 adrenergic antagonist idazoxan, was present in cortex. Quantification by autoradiography also demonstrated the greatest binding in the basal ganglia, with the striatum exhibiting greater binding than the pallidal complex or midbrain regions. For the pallidum, binding in the external segment was higher than the internal segment. Within the midbrain the binding of {sup 125}I-epidepride correlated well with the known distribution of DA-containing cell bodies, with the substantia nigra (pars compacta and pars lateralis) and ventral tegmental area (A10) higher than area A8 and central gray. Binding in frontal and parietal cortex was highest in the internal layers (layers V and VI). Temporal cortex showed a 2-fold higher density of binding than other cortical regions and a trilaminar pattern; binding was greater in the external (layers I and II) and internal layers than in the middle layers (III and IV). This pattern changed in the parahippocampal complex. Within the lateral occipitotemporal cortex, binding was densest in layers I to III and very low in layers IV to VI, but binding was almost nonexistent in the adjacent entorhinal cortex.

  3. Triple-layer laryngeal closure for intractable aspiration.

    PubMed

    Mehmet, Guven; Ibrahim, Aladag; Ahmet, Eyibilen; Yuksel, Kaplan

    2005-07-01

    Impaired laryngeal protective function can result in intractable aspiration, which causes recurrent life-threatening pneumonia. Several surgical operations have been developed to treat intractable aspiration. In this case, we report a successful case of triple-layer laryngeal closure, which was performed in a patient with type II diabetes mellitus and nutritional failure due to intractable aspiration that had been caused by several stroke attacks. Triple-layer laryngeal closure is a unique modified technique that combines laryngotracheal separation and glottic closure operations. The method that we performed can be done more safely in patients who have higher post-operative and general anaesthesia risks.

  4. Electroconvulsive therapy and structural neuroplasticity in neocortical, limbic and paralimbic cortex

    PubMed Central

    Pirnia, T; Joshi, S H; Leaver, A M; Vasavada, M; Njau, S; Woods, R P; Espinoza, R; Narr, K L

    2016-01-01

    Electroconvulsive therapy (ECT) is a highly effective and rapidly acting treatment for severe depression. To understand the biological bases of therapeutic response, we examined variations in cortical thickness from magnetic resonance imaging (MRI) data in 29 patients scanned at three time points during an ECT treatment index series and in 29 controls at two time points. Changes in thickness across time and with symptom improvement were evaluated at high spatial resolution across the cortex and within discrete cortical regions of interest. Patients showed increased thickness over the course of ECT in the bilateral anterior cingulate cortex (ACC), inferior and superior temporal, parahippocampal, entorhinal and fusiform cortex and in distributed prefrontal areas. No changes across time occurred in controls. In temporal and fusiform regions showing significant ECT effects, thickness differed between patients and controls at baseline and change in thickness related to therapeutic response in patients. In the ACC, these relationships occurred in treatment responders only, and thickness measured soon after treatment initiation predicted the overall ECT response. ECT leads to widespread neuroplasticity in neocortical, limbic and paralimbic regions and changes relate to the extent of antidepressant response. Variations in ACC thickness, which discriminate treatment responders and predict response early in the course of ECT, may represent a biomarker of overall clinical outcome. Because post-mortem studies show focal reductions in glial density and neuronal size in patients with severe depression, ECT-related increases in thickness may be attributable to neuroplastic processes affecting the size and/or density of neurons and glia and their connections. PMID:27271858

  5. Electroconvulsive therapy and structural neuroplasticity in neocortical, limbic and paralimbic cortex.

    PubMed

    Pirnia, T; Joshi, S H; Leaver, A M; Vasavada, M; Njau, S; Woods, R P; Espinoza, R; Narr, K L

    2016-06-07

    Electroconvulsive therapy (ECT) is a highly effective and rapidly acting treatment for severe depression. To understand the biological bases of therapeutic response, we examined variations in cortical thickness from magnetic resonance imaging (MRI) data in 29 patients scanned at three time points during an ECT treatment index series and in 29 controls at two time points. Changes in thickness across time and with symptom improvement were evaluated at high spatial resolution across the cortex and within discrete cortical regions of interest. Patients showed increased thickness over the course of ECT in the bilateral anterior cingulate cortex (ACC), inferior and superior temporal, parahippocampal, entorhinal and fusiform cortex and in distributed prefrontal areas. No changes across time occurred in controls. In temporal and fusiform regions showing significant ECT effects, thickness differed between patients and controls at baseline and change in thickness related to therapeutic response in patients. In the ACC, these relationships occurred in treatment responders only, and thickness measured soon after treatment initiation predicted the overall ECT response. ECT leads to widespread neuroplasticity in neocortical, limbic and paralimbic regions and changes relate to the extent of antidepressant response. Variations in ACC thickness, which discriminate treatment responders and predict response early in the course of ECT, may represent a biomarker of overall clinical outcome. Because post-mortem studies show focal reductions in glial density and neuronal size in patients with severe depression, ECT-related increases in thickness may be attributable to neuroplastic processes affecting the size and/or density of neurons and glia and their connections.

  6. Aspiring to physical health: The role of aspirations for physical health in facilitating long-term tobacco abstinence

    PubMed Central

    Niemiec, Christopher P.; Ryan, Richard M.; Deci, Edward L.; Williams, Geoffrey C.

    2009-01-01

    Objective To assess aspirations for physical health over 18 months. To examine whether maintained importance of aspirations for physical health mediated and/or moderated the effect of an intensive intervention on long-term tobacco abstinence. Methods Participants were randomly assigned to an intervention based on self-determination theory or to community care, and provided data at baseline and at 18 and 30 months post-randomization. Results Aspirations for physical health were better maintained over 18 months among participants in the intervention (mean change = .05), relative to community care (mean change = -.13), t = 2.66, p < .01. Maintained importance of aspirations for physical health partially mediated the treatment condition effects on seven-day point prevalence tobacco abstinence (z′ = 1.68, p < .01) and the longest number of days not smoking (z′ = 2.16, p < .01), and interacted with treatment condition to facilitate the longest number of days not smoking (β = .08, p < .05). Conclusion Maintained importance of aspirations for physical health facilitated tobacco abstinence. Practice implications Smokers may benefit from discussing aspirations for physical health within autonomy-supportive interventions. Patients may benefit from discussing aspirations during counseling about therapeutic lifestyle change and medication use. PMID:18838243

  7. Lung ultrasound findings in meconium aspiration syndrome.

    PubMed

    Piastra, Marco; Yousef, Nadya; Brat, Roselyne; Manzoni, Paolo; Mokhtari, Mostafa; De Luca, Daniele

    2014-09-01

    Meconium aspiration syndrome (MAS) is a rare and life-threatening neonatal lung injury induced by meconium in the lung and airways. Lung ultrasound (LUS) is a quick, easy and cheap imaging technique that is increasingly being used in critical care settings, also for newborns. In this paper we describe ultrasound findings in MAS. Six patients with MAS of variable severity were examined by LUS during the first hours of life. Chest X-rays were used as reference. The following dynamic LUS signs were seen in all patients: (1) B-pattern (interstitial) coalescent or sparse; (2) consolidations; (3) atelectasis; (4) bronchograms. No pattern was observed for the distribution of signs in lung areas, although the signs varied with time, probably due to the changing localisation of meconium in the lungs. LUS images corresponded well with X-ray findings. In conclusion, we provide the first formal description of LUS findings in neonates with MAS. LUS is a useful and promising tool in the diagnosis and management of MAS, providing real-time bedside imaging, with the additional potential benefit of limiting radiation exposure in sick neonates.

  8. Percutaneous aspiration thromboembolectomy: a preliminary experience.

    PubMed

    Murray, J G; Brown, A L; Wilkins, R A

    1994-08-01

    Percutaneous aspiration thromboembolectomy (PAT) is a radiological alternative to surgical embolectomy or thrombolysis in the treatment of acute arterial thromboembolic disease. We report our experience in eight patients aged 63-83 years (mean 71 years). Indications were graft thrombosis (1) or emboli from atrial fibrillation (3), abdominal aneurysm (2) or proximal angioplasty (2). PAT was performed at 10 arterial sites; common iliac (1), profunda femoris (1), superficial femoral (2), femoro-popliteal graft (1), popliteal (2) and arteries of the trifurcation (3). PAT was used as an adjunct to thrombolysis or angioplasty in five patients and as the sole procedure in three patients. It was successful in six patients (seven sites) with mean ABI rising from 0.4 pre- to 0.8 post-procedure. Two of the failures required amputations. One of these was a completely thrombosed dacron femoro-popliteal graft with poor run-off, and the second case had a failed surgical embolectomy prior to amputation. There were no major complications, and no mortality on follow-up at 1 month. PAT is a useful adjunct to thrombolysis and balloon angioplasty in the radiological treatment of acute thromboembolic disease. In patients in whom thrombolysis is contraindicated, it offers an alternative to surgical embolectomy.

  9. Amniotic fluid aspiration in cases of SIDS.

    PubMed

    Fracasso, Tony; Karger, Bernd; Vennemann, Mechtild; Bajanowski, Thomas; Golla-Schindler, Ute Maria; Pfeiffer, Heidi

    2010-03-01

    The scope of this study was to evaluate the incidence and the eventual consequences of amniotic fluid aspiration (AFA) in cases of sudden infant death. Cases of sudden infant death syndrome (SIDS; n = 113: 39 females, 74 males; mean age 4.6 months) were compared to a control group of 39 cases of explained death (14 females, 25 males; mean age 5.6 months). In each case, sections of the lung stained with hematoxylin and eosin and with the immunohistochemical reaction 34BE12 specific for cytokeratins were available. The microscope slides were observed at x200 magnification and semi-quantitatively classified into four categories(-, +, ++, and +++). In both groups, rests of amniotic fluid could be observed up to the fourth month of life. The comparison between the two groups did not show any significant difference. In the SIDS group, immunohistochemical reactions with the antibodies CD68, MRP8, MRP14, 27E10, 25F9, CD3, CD20Cy, and CD45R0 were available for the lungs. Twelve cases with AFA were compared to a group of SIDS cases without AFA with similar age and pathological distribution to evaluate whether the presence of amniotic remnants induced inflammatory changes in the lungs. No differences emerged. This study shows that AFA is not a rare event. Even moderate to severe AFA does not necessary cause death. A correlation between AFA and SIDS could not be shown.

  10. Conventional transbronchial needle aspiration in community practice

    PubMed Central

    2015-01-01

    Conventional transbronchial needle aspiration (C-TBNA) provides an opportunity to diagnose mediastinal lesions and stage bronchogenic carcinoma in a minimally invasive fashion. The procedure is easy to learn and requires zero upfront cost. Any community pulmonologist can acquire and maintain the skills of C-TBNA without undergoing formal interventional pulmonary fellowship training. Besides being used for the diagnosis and staging of lung cancer, C-TBNA can be used in patients suspected to have benign conditions such as sarcoidosis and tuberculosis. It also contributes in improving the diagnostic yield of flexible bronchoscopy while dealing with endobronchial, submucosal, peribronchial, or peripheral lesions. C-TBNA may be the only diagnostic modality that can be performed in patients in whom mediastinoscopy is contraindicated due to a bleeding diathesis. The procedure is safe and has great potential to augment the welfare of patients with pulmonary ailments. The learning curve of the procedure is short and steep. Every community pulmonologist should be able to perform C-TBNA. PMID:26807272

  11. Dermal mass aspirate from a Persian cat.

    PubMed

    Zimmerman, Kurt; Feldman, Bernard; Robertson, John; Herring, Erin S; Manning, Thomas

    2003-01-01

    A 1-year-old spayed female Persian cat with alopecia and weight loss had numerous variably ulcerated dermal nodules. Cytologic examination of an aspirate of one of the nodules revealed pyogranulomatous inflammation along with septate hyphae and basophilic round bodies, 0.5-1.0 microm in diameter, surrounded by a thin clear halo (arthrospores). The cytologic diagnosis was dermatophytic pseudomycetoma. Histologically, there were dermal granulomas containing poorly staining, septate hyphae with bulbous spores embedded within abundant amorphous eosinophilic material (Splendore-Hoeppli reaction), and the histologic diagnosis was pseudomycetoma-associated chronic multifocal severe granulomatous dermatitis with lymphocytic perifolliculitis and furunculosis. Microsporum canis was cultured from the lesion. Pseudomycetomas are distinguished from fungal mycetomas, or eumycotic mycetomas, by the findings of multiple lesions, lack of a history of skin trauma, an association with dermatophytes, most commonly Microsporum canis, and, histologically, lack of true cement material and a more abundant Splendore-Hoeppli reaction in pseudomycetomas. Additionally, pseudomycetomas differ from dermatophytosis, in which lesions are restricted to epidermal structures. Persian cats have a high incidence of pseudomycetoma formation, suggesting a heritable predisposition. The prognosis is fair with systemic antifungal therapy. When examining cytologic specimens from Persian cats with single or multiple dermal nodules, especially if pyogranulomatous inflammation is present, a diagnosis of pseudomycetoma should be suspected and is warranted if arthrospores and refractile septate hyphae are present.

  12. Hollow needle cataract aspiration in antiquity.

    PubMed

    Pérez-Cambrodí, Rafael J; Ascaso, Francisco J; Diab, Fathi; Alzamora-Rodríguez, Antonio; Grzybowski, Andrzej

    2015-12-01

    The dislocation of the crystalline lens or couching technique was the predominant procedure to surgically remove cataracts until the 18th century A.D. However, in the Middle Ages, some Arab physicians tried to aspirate the opaque lens by means of a glass tube following a paracentesis. Some literary sources attributed the origins of this technique to Antyllus of Alexandria, a Greek surgeon who lived in the 2nd century A.D. in the Roman Empire. Nevertheless, this statement remains unclear and is probably the consequence of posterior interpretations or incorrect translations of the manuscripts. In recent years, the discovery of the hollow needles from Montbellet (France) and Viladamat (Spain), in archaeological settlements dated between the 1st century and 3rd century A.D., has reopened the possibility of cataract extraction as an option in the surgical management of soft cataracts in the antiquity. In any case, these findings are exceptional, and thus, probably this technique was not widely practised and very likely disparaged by the medical community.

  13. Prevention of suicide: aspirations and evidence.

    PubMed Central

    Gunnell, D.; Frankel, S.

    1994-01-01

    The Health of the Nation white paper set a target for 15% reduction in overall suicide rates by the year 2000. If the targets are to be achieved interventions must be identified which are of proved effectiveness. This paper examines the evidence on the available interventions and points of access to the population at risk. No single intervention has been shown in a well conducted randomised controlled trial to reduce suicide. The greatest potential seems to arise from limiting the availability of methods. In particular it is likely that the introduction of the catalytic convertor will lead to reduced lethality of care exhausts and reductions in suicide using this method. General practitioner education programmes, the effectiveness of lithium and maintenance antidepressants, and limits on the quantity of medicines available over the counter or on prescription should all be evaluated. Particular high risk groups include people recently discharged from psychiatric hospitals and those with a history of parasuicide. Many social processes affect suicide rates and these rather than specific interventions may help or hinder the ability to realise the Health of the Nation targets. Well conducted trials are essential to distinguish complex social processes from the effects of specific interventions for suicide prevention. This review of the available evidence offers little support for the aspiration that the posited targets can be achieved on the basis of current knowledge and current policy. Images p1229-a p1233-a PMID:8080520

  14. Ultrasound-guided prostate biopsy. Biopty gun superior to aspiration.

    PubMed

    Ragde, H; Aldape, H C; Bagley, C M

    1988-12-01

    We used a 7 MHz transrectal ultrasound scanner to perform guided core biopsy and aspiration cytologies on 292 patients with findings suspicious for prostate cancer. One hundred two cancers were identified, 35 of which were not palpable and were detected only by ultrasound. Aspiration needles were guided by ultrasound through the center of the suspicious lesion. Core biopsies were performed using an 18-gauge Tru-Cut type of needle with an automatic, spring-powered needle biopsy device (Biopty). All patients received only local anesthetic and biopsies were done as an outpatient office procedure. The core biopsies gave excellent specimens which detected 89 percent of the cancers, whereas the aspiration method detected 51 percent (P less than 0.001). Aspiration cytology was significantly less sensitive among well-differentiated compared with moderately differentiated cancers. High-resolution transrectal ultrasound and the Biopty device are detecting and documenting prostate cancer with much greater sensitivity than preceding techniques have achieved.

  15. Ultrasound-Guided Fine Needle Aspiration Biopsy of the Thyroid

    MedlinePlus

    ... nodule and aspirate samples of tissue. After the sampling, the needle will be removed. New needles will ... for adequate biopsies. Needle biopsy is a reliable method of obtaining tissue samples that can help diagnose ...

  16. Ultrasound-guided needle aspiration of amoebic liver abscess.

    PubMed Central

    Ramani, A.; Ramani, R.; Kumar, M. S.; Lakhkar, B. N.; Kundaje, G. N.

    1993-01-01

    This prospective study was carried out on 200 patients with clinically, ultrasonographically and serologically confirmed amoebic liver abscess. The role of ultrasound-guided needle aspiration in addition to medications was evaluated compared to drug treatment alone. Both the groups were monitored clinically and sonographically for up to 6 months after diagnosis. The initial response (after 15 days) was better in the aspirated group (P < 0.05) but resolution of abscess after 6 months were similar. There was a more rapid clinical response in the aspirated group, particularly in those with larger (> 6 cm) abscesses and there were no complications. Percutaneous ultrasound-guided needle aspiration is a safe diagnostic and therapeutic approach which enhances clinical recovery, accelerates resolution, especially in large abscesses, and prevents complications. PMID:8346134

  17. The role of incentives in nurses' aspirations to management roles.

    PubMed

    Wong, Carol A; Spence Laschinger, Heather K; Cziraki, Karen

    2014-06-01

    The objective of this study was to describe findings from a study examining nurses' perceptions of incentives for pursuing management roles. Upcoming retirements of nurse managers and a reported lack of interest in manager roles signal concerns about a leadership shortage. However, there is limited research on nurses' career aspirations and specifically the effect of perceived incentives for pursuing manager roles. Data from a national, cross-sectional survey of Canadian nurses were analyzed (n = 1241) using multiple regression to measure the effect of incentives on nurses' career aspirations. Twenty-four percent of nurses expressed interest in pursuing management roles. Age, education, and incentives explained 43% of the variance in career aspirations. Intrinsically oriented incentives such as new challenges, autonomy, and the opportunity to influence others were the strongest predictors of aspirations to management roles. Ensuring an adequate supply of nurse managers will require proactive investment in the identification, recruitment, and development of nurses with leadership potential.

  18. Current Concepts in the Management of Meconium Aspiration Syndrome.

    PubMed

    Chettri, Subhash; Bhat, B Vishnu; Adhisivam, B

    2016-10-01

    In developing countries, meconium aspiration syndrome (MAS) is an important cause of morbidity and mortality among neonates. The concepts of pathophysiology and management of meconium stained amniotic fluid (MSAF) and meconium aspiration syndrome have undergone tremendous change in recent years. Routine intranatal and postnatal endotracheal suctioning of meconium in vigorous infants is no longer recommended. Recent studies have challenged its role even in non-vigorous infants. Supportive therapy like oxygen supplementation, mechanical ventilation and intravenous fluids are the cornerstone in the management of meconium aspiration syndrome. Availability of surfactant, inhaled nitric oxide, high frequency ventilators and extracorporeal membrane oxygenation has made it possible to salvage more infants with meconium aspiration syndrome. In this review the authors have discussed the current concepts in the pathophysiology and management of MAS. Drugs in trials and future therapeutic targets are also discussed briefly.

  19. Cognitive correlates of adolescents' aspirations to leadership: a developmental study.

    PubMed

    Singer, M

    1990-06-01

    The study examined age and gender differences in leadership aspirations among teenage adolescents. It was hypothesized that adolescents' valence, self-efficacy and attribution perceptions about leadership would be predictive of their aspirations to leadership. Altogether 52 fourth form and 78 seventh form high school students completed a questionnaire measuring (a) overall leadership aspirations, (b) 13 valence-instrumentality expectancies for 13 leadership outcomes, (c) self-efficacy perceptions, and (d) attributions of effective leadership. The results revealed significant gender differences in valence scores and significant age differences in self-efficacy and attribution measures. Regression analyses indicated that fourth formers' leadership aspirations were significantly predicted from their "ease-of-success" self-efficacy expectation; whereas seventh formers from either valence perceptions (males) or self-efficacy and attribution scores (females). These results were discussed in the context of the valence and self-efficacy models of career decision-making processes and attribution theory.

  20. Cross-Lagged Relationships between Career Aspirations and Goal Orientation in Early Adolescents

    ERIC Educational Resources Information Center

    Creed, Peter; Tilbury, Clare; Buys, Nick; Crawford, Meegan

    2011-01-01

    We surveyed 217 students (145 girls; average age = 14.6 years) on two occasions, twelve months apart, on measures of career aspirations (job aspirations, job expectations, educational aspirations) and goal orientation (learning, performance-prove, performance-avoid), and tested the causal relationship between goal orientation and aspirations. We…