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Sample records for fronto-occipital fasciculus ifof

  1. The left inferior fronto-occipital fasciculus subserves language semantics: a multilevel lesion study.

    PubMed

    Almairac, Fabien; Herbet, Guillaume; Moritz-Gasser, Sylvie; de Champfleur, Nicolas Menjot; Duffau, Hugues

    2015-07-01

    Consequential works in cognitive neuroscience have led to the formulation of an interactive dual-stream model of language processing: the dorsal stream may process the phonological aspects of language, whereas the ventral stream may process the semantic aspects of language. While it is well-accepted that the dorsal route is subserved by the arcuate fasciculus, the structural connectivity of the semantic ventral stream is a matter of dispute. Here we designed a longitudinal study to gain new insights into this central but controversial question. Thirty-one patients harboring a left diffuse low-grade glioma—a rare neurological condition that infiltrates preferentially white matter associative pathways—were assessed with a prototypical task of language (i.e. verbal fluency) before and after surgery. All were operated under local anesthesia with a cortical and subcortical brain mapping—enabling to identify and preserve eloquent structures for language. We performed voxel-based lesion-symptom (VLSM) analyses on pre- and postoperative behavioral data. Preoperatively, we found a significant relationship between semantic fluency scores and the white matter fibers shaping the ventro-lateral connectivity (P < 0.05 corrected). The statistical map was found to substantially overlap with the spatial position of the inferior fronto-occipital fasciculus (IFOF) (37.7%). Furthermore, a negative correlation was observed between semantic fluency scores and the infiltration volumes in this fasciculus (r = -0.4, P = 0.029). Postoperatively, VLSM analyses were inconclusive. Taken as a whole and when combined with the literature data, our findings strengthen the view that the IFOF plays an essential role in semantic processing and may subserve the direct ventral pathway of language. PMID:24744151

  2. The controversial existence of the human superior fronto-occipital fasciculus: Connectome-based tractographic study with microdissection validation.

    PubMed

    Meola, Antonio; Comert, Ayhan; Yeh, Fang-Cheng; Stefaneanu, Lucia; Fernandez-Miranda, Juan C

    2015-12-01

    The superior fronto-occipital fasciculus (SFOF), a long association bundle that connects frontal and occipital lobes, is well-documented in monkeys but is controversial in human brain. Its assumed role is in visual processing and spatial awareness. To date, anatomical and neuroimaging studies on human and animal brains are not in agreement about the existence, course, and terminations of SFOF. To clarify the existence of the SFOF in human brains, we applied deterministic fiber tractography to a template of 488 healthy subjects and to 80 individual subjects from the Human Connectome Project (HCP) and validated the results with white matter microdissection of post-mortem human brains. The imaging results showed that previous reconstructions of the SFOF were generated by two false continuations, namely between superior thalamic peduncle (STP) and stria terminalis (ST), and ST and posterior thalamic peduncle. The anatomical microdissection confirmed this finding. No other fiber tracts in the previously described location of the SFOF were identified. Hence, our data suggest that the SFOF does not exist in the human brain. Hum Brain Mapp 36:4964-4971, 2015. © 2015 Wiley Periodicals, Inc. PMID:26435158

  3. Altered hemispheric lateralization of white matter pathways in developmental dyslexia: Evidence from spherical deconvolution tractography.

    PubMed

    Zhao, Jingjing; Thiebaut de Schotten, Michel; Altarelli, Irene; Dubois, Jessica; Ramus, Franck

    2016-03-01

    This study examines the structural integrity and the hemispheric lateralization patterns of four major association fiber pathways in a group of French dyslexic children and age-matched controls (from 9 to 14 years), using high angular diffusion imaging combined with spherical deconvolution tractography. Compared with age-matched controls, dyslexic children show increased hindrance-modulated oriented anisotropy (HMOA) in the right superior longitudinal fasciculus (SLF). They also show a reduced leftward asymmetry of the inferior fronto-occipital fasciculus (IFOF) and an increased rightward asymmetry of the second branch of the SLF (SLF II). The lateralization pattern of IFOF and SLF II also accounts for individual differences in dyslexic children's reading abilities. These data provide evidence for an abnormal lateralization of occipito-frontal and parieto-frontal pathways in developmental dyslexia. PMID:26859852

  4. Damage to association fiber tracts impairs recognition of the facial expression of emotion.

    PubMed

    Philippi, Carissa L; Mehta, Sonya; Grabowski, Thomas; Adolphs, Ralph; Rudrauf, David

    2009-12-01

    An array of cortical and subcortical structures have been implicated in the recognition of emotion from facial expressions. It remains unknown how these regions communicate as parts of a system to achieve recognition, but white matter tracts are likely critical to this process. We hypothesized that (1) damage to white matter tracts would be associated with recognition impairment and (2) the degree of disconnection of association fiber tracts [inferior longitudinal fasciculus (ILF) and/or inferior fronto-occipital fasciculus (IFOF)] connecting the visual cortex with emotion-related regions would negatively correlate with recognition performance. One hundred three patients with focal, stable brain lesions mapped onto a reference brain were tested on their recognition of six basic emotional facial expressions. Association fiber tracts from a probabilistic atlas were coregistered to the reference brain. Parameters estimating disconnection were entered in a general linear model to predict emotion recognition impairments, accounting for lesion size and cortical damage. Damage associated with the right IFOF significantly predicted an overall facial emotion recognition impairment and specific impairments for sadness, anger, and fear. One subject had a pure white matter lesion in the location of the right IFOF and ILF. He presented specific, unequivocal emotion recognition impairments. Additional analysis suggested that impairment in fear recognition can result from damage to the IFOF and not the amygdala. Our findings demonstrate the key role of white matter association tracts in the recognition of the facial expression of emotion and identify specific tracts that may be most critical. PMID:19955360

  5. Testing the connections within face processing circuitry in Capgras delusion with diffusion imaging tractography

    PubMed Central

    Bobes, Maria A.; Góngora, Daylin; Valdes, Annette; Santos, Yusniel; Acosta, Yanely; Fernandez Garcia, Yuriem; Lage, Agustin; Valdés-Sosa, Mitchell

    2016-01-01

    Although Capgras delusion (CD) patients are capable of recognizing familiar faces, they present a delusional belief that some relatives have been replaced by impostors. CD has been explained as a selective disruption of a pathway processing affective values of familiar faces. To test the integrity of connections within face processing circuitry, diffusion tensor imaging was performed in a CD patient and 10 age-matched controls. Voxel-based morphometry indicated gray matter damage in right frontal areas. Tractography was used to examine two important tracts of the face processing circuitry: the inferior fronto-occipital fasciculus (IFOF) and the inferior longitudinal (ILF). The superior longitudinal fasciculus (SLF) and commissural tracts were also assessed. CD patient did not differ from controls in the commissural fibers, or the SLF. Right and left ILF, and right IFOF were also equivalent to those of controls. However, the left IFOF was significantly reduced respect to controls, also showing a significant dissociation with the ILF, which represents a selective impairment in the fiber-tract connecting occipital and frontal areas. This suggests a possible involvement of the IFOF in affective processing of faces in typical observers and in covert recognition in some cases with prosopagnosia. PMID:26909325

  6. Higher integrity of the motor and visual pathways in long-term video game players

    PubMed Central

    Du, Guijin; Yang, Yongxin; Qin, Wen; Li, Xiaodong; Zhang, Quan

    2015-01-01

    Long term video game players (VGPs) exhibit superior visual and motor skills compared with non-video game control subjects (NVGCs). However, the neural basis underlying the enhanced behavioral performance remains largely unknown. To clarify this issue, the present study compared the whiter matter integrity within the corticospinal tracts (CST), the superior longitudinal fasciculus (SLF), the inferior longitudinal fasciculus (ILF), and the inferior fronto-occipital fasciculus (IFOF) between the VGPs and the NVGCs using diffusion tensor imaging. Compared with the NVGCs, voxel-wise comparisons revealed significantly higher fractional anisotropy (FA) values in some regions within the left CST, left SLF, bilateral ILF, and IFOF in VGPs. Furthermore, higher FA values in the left CST at the level of cerebral peduncle predicted a faster response in visual attention tasks. These results suggest that higher white matter integrity in the motor and higher-tier visual pathways is associated with long-term video game playing, which may contribute to the understanding on how video game play influences motor and visual performance. PMID:25805981

  7. Role of Frontotemporal Fiber Tract Integrity in Task-Switching Performance of Healthy Controls and Patients with Temporal Lobe Epilepsy

    PubMed Central

    Kucukboyaci, N. Erkut; Girard, H.M.; Hagler, D.J.; Kuperman, J.; Tecoma, E.S.; Iragui, V.J.; Halgren, E.; McDonald, C.R.

    2012-01-01

    The objective of this study is to investigate the relationships among frontotemporal fiber tract compromise and task-switching performance in healthy controls and patients with temporal lobe epilepsy (TLE). We performed diffusion tensor imaging (DTI) on 30 controls and 32 patients with TLE (15 left TLE). Fractional anisotropy (FA) was calculated for four fiber tracts [uncinate fasciculus (UncF), arcuate fasciculus (ArcF), dorsal cingulum (CING), and inferior fronto-occipital fasciculus (IFOF)]. Participants completed the Trail Making Test-B (TMT-B) and Verbal Fluency Category Switching (VFCS) test. Multivariate analyses of variances (MANOVAs) were performed to investigate group differences in fiber FA and set-shifting performances. Canonical correlations were used to examine the overall patterns of structural-cognitive relationships and were followed by within-group bivariate correlations. We found a significant canonical correlation between fiber FA and task-switching performance. In controls, TMT-B correlated with left IFOF, whereas VFCS correlated with FA of left ArcF and left UncF. These correlations were not significant in patients with TLE. We report significant correlations between frontotemporal fiber tract integrity and set-shifting performance in healthy controls that appear to be absent or attenuated in patients with TLE. These findings suggest a breakdown of typical structure-function relationships in TLE that may reflect aberrant developmental or degenerative processes. PMID:22014246

  8. Altered Microstructure Within Social-Cognitive Brain Networks During Childhood in Williams Syndrome

    PubMed Central

    Haas, Brian W.; Barnea-Goraly, Naama; Sheau, Kristen E.; Yamagata, Bun; Ullas, Shruti; Reiss, Allan L.

    2014-01-01

    Williams syndrome (WS) is a neurodevelopmental condition caused by a hemizygous deletion of ∼26–28 genes on chromosome 7q11.23. WS is associated with a distinctive pattern of social cognition. Accordingly, neuroimaging studies show that WS is associated with structural alterations of key brain regions involved in social cognition during adulthood. However, very little is currently known regarding the neuroanatomical structure of social cognitive brain networks during childhood in WS. This study used diffusion tensor imaging to investigate the structural integrity of a specific set of white matter pathways (inferior fronto-occipital fasciculus [IFOF] and uncinate fasciculus [UF]) and associated brain regions [fusiform gyrus (FG), amygdala, hippocampus, medial orbitofrontal gyrus (MOG)] known to be involved in social cognition in children with WS and a typically developing (TD) control group. Children with WS exhibited higher fractional anisotropy (FA) and axial diffusivity values and lower radial diffusivity and apparent diffusion coefficient (ADC) values within the IFOF and UF, higher FA values within the FG, amygdala, and hippocampus and lower ADC values within the FG and MOG compared to controls. These findings provide evidence that the WS genetic deletion affects the development of key white matter pathways and brain regions important for social cognition. PMID:23709644

  9. Evaluation of Diffusion-Tensor Imaging-Based Global Search and Tractography for Tumor Surgery Close to the Language System

    PubMed Central

    Richter, Mirco; Zolal, Amir; Ganslandt, Oliver; Buchfelder, Michael; Nimsky, Christopher; Merhof, Dorit

    2013-01-01

    Pre-operative planning and intra-operative guidance in neurosurgery require detailed information about the location of functional areas and their anatomo-functional connectivity. In particular, regarding the language system, post-operative deficits such as aphasia can be avoided. By combining functional magnetic resonance imaging and diffusion tensor imaging, the connectivity between functional areas can be reconstructed by tractography techniques that need to cope with limitations such as limited resolution and low anisotropic diffusion close to functional areas. Tumors pose particular challenges because of edema, displacement effects on brain tissue and infiltration of white matter. Under these conditions, standard fiber tracking methods reconstruct pathways of insufficient quality. Therefore, robust global or probabilistic approaches are required. In this study, two commonly used standard fiber tracking algorithms, streamline propagation and tensor deflection, were compared with a previously published global search, Gibbs tracking and a connection-oriented probabilistic tractography approach. All methods were applied to reconstruct neuronal pathways of the language system of patients undergoing brain tumor surgery, and control subjects. Connections between Broca and Wernicke areas via the arcuate fasciculus (AF) and the inferior fronto-occipital fasciculus (IFOF) were validated by a clinical expert to ensure anatomical feasibility, and compared using distance- and diffusion-based similarity metrics to evaluate their agreement on pathway locations. For both patients and controls, a strong agreement between all methods was observed regarding the location of the AF. In case of the IFOF however, standard fiber tracking and Gibbs tracking predominantly identified the inferior longitudinal fasciculus that plays a secondary role in semantic language processing. In contrast, global search resolved connections in almost every case via the IFOF which could be confirmed by probabilistic fiber tracking. The results show that regarding the language system, our global search is superior to clinically applied conventional fiber tracking strategies with results similar to time-consuming global or probabilistic approaches. PMID:23308093

  10. White matter fractional anisotropy over two time points in early onset schizophrenia and adolescent cannabis use disorder: A naturalistic diffusion tensor imaging study.

    PubMed

    Epstein, Katherine A; Kumra, Sanjiv

    2015-04-30

    Recurrent exposure to cannabis in adolescence increases the risk for later development of psychosis, but there are sparse data regarding the impact of cannabis use on brain structure during adolescence. This pilot study investigated the effect of cannabis use disorder (CUD) upon white matter fractional anisotropy (WM FA) values in non-psychotic treatment-seeking adolescents relative to adolescents with early onset schizophrenia-spectrum disorders (EOSS) and to healthy control (HC) participants. Diffusion tensor imaging (DTI) and tractography methods were used to examine fractional anisotropy (FA) of the cingulum bundle, superior longitudinal fasciculus (SLF), corticospinal tract (CST), inferior longitudinal fasciculus (ILF), inferior fronto-occipital fasciculus (IFOF) and uncinate fasciculus in adolescents with EOSS (n=34), CUD (n=19) and HC (n=29). Participants received DTI and substance use assessments at baseline and at 18-month follow-up. Using multivariate analysis of variance, a significant main effect of diagnostic group was observed. Post-hoc testing revealed that adolescents with CUD showed an altered change in FA values in the left ILF and in the left IFOF (trend level) compared with HC adolescents. Greater consumption of cannabis during the inter-scan interval predicted a greater decrease in left ILF FA in CUD. These preliminary longitudinal data suggest that heavy cannabis use during adolescence, or some factor associated with cannabis use, is associated with an altered change in WM FA values in a fiber bundle that has been implicated in the pathophysiology of EOSS (i.e., the left ILF). Additional studies are needed to clarify the clinical significance of these findings. PMID:25779033

  11. Involuntary switching into the native language induced by electrocortical stimulation of the superior temporal gyrus: a multimodal mapping study.

    PubMed

    Tomasino, Barbara; Marin, Dario; Canderan, Cinzia; Maieron, Marta; Budai, Riccardo; Fabbro, Franco; Skrap, Miran

    2014-09-01

    We describe involuntary language switching from L2 to L1 evoked by electro-stimulation in the superior temporal gyrus in a 30-year-old right-handed Serbian (L1) speaker who was also a late Italian learner (L2). The patient underwent awake brain surgery. Stimulation of other portions of the exposed cortex did not cause language switching as did not stimulation of the left inferior frontal gyrus, where we evoked a speech arrest. Stimulation effects on language switching were selective, namely, interfered with counting behaviour but not with object naming. The coordinates of the positive site were combined with functional and fibre tracking (DTI) data. Results showed that the language switching site belonged to a significant fMRI cluster in the left superior temporal gyrus/supramarginal gyrus found activated for both L1 and L2, and for both the patient and controls, and did not overlap with the inferior fronto-occipital fasciculus (IFOF), the inferior longitudinal fasciculus (ILF) and the superior longitudinal fasciculus (SLF). This area, also known as Stp, has a role in phonological processing. Language switching phenomenon we observed can be partly explained by transient dysfunction of the feed-forward control mechanism hypothesized by the DIVA (Directions Into Velocities of Articulators) model (Golfinopoulos, E., Tourville, J. A., & Guenther, F. H. (2010). The integration of large-scale neural network modeling and functional brain imaging in speech motor control. PMID:25058058

  12. Structural Variability within Frontoparietal Networks and Individual Differences in Attentional Functions: An Approach Using the Theory of Visual Attention

    PubMed Central

    Gillebert, Celine R.; Vangkilde, Signe A.; Petersen, Anders; Humphreys, Glyn W.

    2015-01-01

    Visuospatial attention allows us to select and act upon a subset of behaviorally relevant visual stimuli while ignoring distraction. Bundesen's theory of visual attention (TVA) (Bundesen, 1990) offers a quantitative analysis of the different facets of attention within a unitary model and provides a powerful analytic framework for understanding individual differences in attentional functions. Visuospatial attention is contingent upon large networks, distributed across both hemispheres, consisting of several cortical areas interconnected by long-association frontoparietal pathways, including three branches of the superior longitudinal fasciculus (SLF I-III) and the inferior fronto-occipital fasciculus (IFOF). Here we examine whether structural variability within human frontoparietal networks mediates differences in attention abilities as assessed by the TVA. Structural measures were based on spherical deconvolution and tractography-derived indices of tract volume and hindrance-modulated orientational anisotropy (HMOA). Individual differences in visual short-term memory (VSTM) were linked to variability in the microstructure (HMOA) of SLF II, SLF III, and IFOF within the right hemisphere. Moreover, VSTM and speed of information processing were linked to hemispheric lateralization within the IFOF. Differences in spatial bias were mediated by both variability in microstructure and volume of the right SLF II. Our data indicate that the microstructural and macrostrucutral organization of white matter pathways differentially contributes to both the anatomical lateralization of frontoparietal attentional networks and to individual differences in attentional functions. We conclude that individual differences in VSTM capacity, processing speed, and spatial bias, as assessed by TVA, link to variability in structural organization within frontoparietal pathways. PMID:26224851

  13. Structural Variability within Frontoparietal Networks and Individual Differences in Attentional Functions: An Approach Using the Theory of Visual Attention.

    PubMed

    Chechlacz, Magdalena; Gillebert, Celine R; Vangkilde, Signe A; Petersen, Anders; Humphreys, Glyn W

    2015-07-29

    Visuospatial attention allows us to select and act upon a subset of behaviorally relevant visual stimuli while ignoring distraction. Bundesen's theory of visual attention (TVA) (Bundesen, 1990) offers a quantitative analysis of the different facets of attention within a unitary model and provides a powerful analytic framework for understanding individual differences in attentional functions. Visuospatial attention is contingent upon large networks, distributed across both hemispheres, consisting of several cortical areas interconnected by long-association frontoparietal pathways, including three branches of the superior longitudinal fasciculus (SLF I-III) and the inferior fronto-occipital fasciculus (IFOF). Here we examine whether structural variability within human frontoparietal networks mediates differences in attention abilities as assessed by the TVA. Structural measures were based on spherical deconvolution and tractography-derived indices of tract volume and hindrance-modulated orientational anisotropy (HMOA). Individual differences in visual short-term memory (VSTM) were linked to variability in the microstructure (HMOA) of SLF II, SLF III, and IFOF within the right hemisphere. Moreover, VSTM and speed of information processing were linked to hemispheric lateralization within the IFOF. Differences in spatial bias were mediated by both variability in microstructure and volume of the right SLF II. Our data indicate that the microstructural and macrostrucutral organization of white matter pathways differentially contributes to both the anatomical lateralization of frontoparietal attentional networks and to individual differences in attentional functions. We conclude that individual differences in VSTM capacity, processing speed, and spatial bias, as assessed by TVA, link to variability in structural organization within frontoparietal pathways. PMID:26224851

  14. Applying a free-water correction to diffusion imaging data uncovers stress-related neural pathology in depression

    PubMed Central

    Bergamino, Maurizio; Pasternak, Ofer; Farmer, Madison; Shenton, Martha E.; Paul Hamilton, J.

    2015-01-01

    Diffusion tensor imaging (DTI) holds promise for developing our understanding of white-matter pathology in major depressive disorder (MDD). Variable findings in DTI-based investigations of MDD, however, have thwarted development of this literature. Effects of extra-cellular free-water on the sensitivity of DTI metrics could account for some of this inconsistency. Here we investigated whether applying a free-water correction algorithm to DTI data could improve the sensitivity to detect clinical effects using DTI metrics. Only after applying this correction, we found: a) significantly decreased fractional anisotropy and axial diffusivity (AD) in the left inferior fronto-occipital fasciculus (IFOF) in MDD; and b) increased self-reported stress that significantly correlated with decreased IFOF AD in depression. We estimated and confirmed the robustness of differences observed between free-water corrected and uncorrected approaches using bootstrapping. We conclude that applying a free-water correction to DTI data increases the sensitivity of DTI-based metrics to detect clinical effects in MDD. PMID:27006903

  15. Dissecting the uncinate fasciculus: disorders, controversies and a hypothesis

    PubMed Central

    Von Der Heide, Rebecca J.; Skipper, Laura M.; Klobusicky, Elizabeth

    2013-01-01

    The uncinate fasciculus is a bidirectional, long-range white matter tract that connects lateral orbitofrontal cortex and Brodmann area 10 with the anterior temporal lobes. Although abnormalities in the uncinate fasciculus have been associated with several psychiatric disorders and previous studies suggest it plays a putative role in episodic memory, language and social emotional processing, its exact function is not well understood. In this review we summarize what is currently known about the anatomy of the uncinate, we review its role in psychiatric and neurological illnesses, and we evaluate evidence related to its putative functions. We propose that an overarching role of the uncinate fasciculus is to allow temporal lobe-based mnemonic associations (e.g. an individual’s name + face + voice) to modify behaviour through interactions with the lateral orbitofrontal cortex, which provides valence-based biasing of decisions. The bidirectionality of the uncinate fasciculus information flow allows orbital frontal cortex-based reward and punishment history to rapidly modulate temporal lobe-based mnemonic representations. According to this view, disruption of the uncinate may cause problems in the expression of memory to guide decisions and in the acquisition of certain types of learning and memory. Moreover, uncinate perturbation should cause problems that extend beyond memory to include social–emotional problems owing to people and objects being stripped of personal value and emotional history and lacking in higher-level motivational value. PMID:23649697

  16. The Role of the Arcuate Fasciculus in Conduction Aphasia

    ERIC Educational Resources Information Center

    Bernal, Byron; Ardila, Alfredo

    2009-01-01

    In aphasia literature, it has been considered that a speech repetition defect represents the main constituent of conduction aphasia. Conduction aphasia has frequently been interpreted as a language impairment due to lesions of the arcuate fasciculus (AF) that disconnect receptive language areas from expressive ones. Modern neuroradiological…

  17. The Role of the Arcuate Fasciculus in Conduction Aphasia

    ERIC Educational Resources Information Center

    Bernal, Byron; Ardila, Alfredo

    2009-01-01

    In aphasia literature, it has been considered that a speech repetition defect represents the main constituent of conduction aphasia. Conduction aphasia has frequently been interpreted as a language impairment due to lesions of the arcuate fasciculus (AF) that disconnect receptive language areas from expressive ones. Modern neuroradiological…

  18. Analysis of the volumetric relationship among human ocular, orbital and fronto-occipital cortical morphology.

    PubMed

    Masters, Michael; Bruner, Emiliano; Queer, Sarah; Traynor, Sarah; Senjem, Jess

    2015-10-01

    Recent research on the visual system has focused on investigating the relationship among eye (ocular), orbital, and visual cortical anatomy in humans. This issue is relevant in evolutionary and medical fields. In terms of evolution, only in modern humans and Neandertals are the orbits positioned beneath the frontal lobes, with consequent structural constraints. In terms of medicine, such constraints can be associated with minor deformation of the eye, vision defects, and patterns of integration among these features, and in association with the frontal lobes, are important to consider in reconstructive surgery. Further study is therefore necessary to establish how these variables are related, and to what extent ocular size is associated with orbital and cerebral cortical volumes. Relationships among these anatomical components were investigated using magnetic resonance images from a large sample of 83 individuals, which also included each subject's body height, age, sex, and uncorrected visual acuity score. Occipital and frontal gyri volumes were calculated using two different cortical parcellation tools in order to provide a better understanding of how the eye and orbit vary in relation to visual cortical gyri, and frontal cortical gyri which are not directly related to visual processing. Results indicated that ocular and orbital volumes were weakly correlated, and that eye volume explains only a small proportion of the variance in orbital volume. Ocular and orbital volumes were also found to be equally and, in most cases, more highly correlated with five frontal lobe gyri than with occipital lobe gyri associated with V1, V2, and V3 of the visual cortex. Additionally, after accounting for age and sex variation, the relationship between ocular and total visual cortical volume was no longer statistically significant, but remained significantly related to total frontal lobe volume. The relationship between orbital and visual cortical volumes remained significant for a number of occipital lobe gyri even after accounting for these cofactors, but was again found to be more highly correlated with the frontal cortex than with the occipital cortex. These results indicate that eye volume explains only a small amount of variation in orbital and visual cortical volume, and that the eye and orbit are generally more structurally associated with the frontal lobes than they are functionally associated with the visual cortex of the occipital lobes. Results also demonstrate that these components of the visual system are highly complex and influenced by a multitude of factors in humans. PMID:26250048

  19. Individual structural differences in left inferior parietal area are associated with schoolchildrens' arithmetic scores

    PubMed Central

    Li, Yongxin; Hu, Yuzheng; Wang, Yunqi; Weng, Jian; Chen, Feiyan

    2013-01-01

    Arithmetic skill is of critical importance for academic achievement, professional success and everyday life, and childhood is the key period to acquire this skill. Neuroimaging studies have identified that left parietal regions are a key neural substrate for representing arithmetic skill. Although the relationship between functional brain activity in left parietal regions and arithmetic skill has been studied in detail, it remains unclear about the relationship between arithmetic achievement and structural properties in left inferior parietal area in schoolchildren. The current study employed a combination of voxel-based morphometry (VBM) for high-resolution T1-weighted images and fiber tracking on diffusion tensor imaging (DTI) to examine the relationship between structural properties in the inferior parietal area and arithmetic achievement in 10-year-old schoolchildren. VBM of the T1-weighted images revealed that individual differences in arithmetic scores were significantly and positively correlated with the gray matter (GM) volume in the left intraparietal sulcus (IPS). Fiber tracking analysis revealed that the forceps major, left superior longitudinal fasciculus (SLF), bilateral inferior longitudinal fasciculus (ILF) and inferior fronto-occipital fasciculus (IFOF) were the primary pathways connecting the left IPS with other brain areas. Furthermore, the regression analysis of the probabilistic pathways revealed a significant and positive correlation between the fractional anisotropy (FA) values in the left SLF, ILF and bilateral IFOF and arithmetic scores. The brain structure-behavior correlation analyses indicated that the GM volumes in the left IPS and the FA values in the tract pathways connecting left IPS were both related to children's arithmetic achievement. The present findings provide evidence that individual structural differences in the left IPS are associated with arithmetic scores in schoolchildren. PMID:24367320

  20. The Superior Longitudinal Fasciculus in Typically Developing Children and Adolescents: Diffusion Tensor Imaging and Neuropsychological Correlates

    PubMed Central

    Urger, Sacide E.; De Bellis, Michael D.; Hooper, Stephen R.; Woolley, Donald P.; Chen, Steven D.; Provenzale, James

    2014-01-01

    The relationship between superior longitudinal fasciculus microstructural integrity and neuropsychological functions were examined in 49 healthy children (range: 5–17 years) using diffusion tensor imaging. Seven major cognitive domains (intellegience, fine-motor, attention, language, visual-spatial, memory, executive function) were assessed. Data analyses utilized correlational methods. After adjusting for age and gender, fractional anisotropy and axial diffusivity values in the superior longitudinal fasciculus were positively correlated with executive functions of set-shifting; while left superior longitudinal fasciculus fractional anisotropy values correlated with attention and language. Apparent diffusion coefficient values in the left superior longitudinal fasciculus negatively correlated with inhibitory control. In the left arcuate fasciculus, fractional anisotropy correlated with IQ and attention; while radial diffusivity values negatively correlated with IQ, fine-motor skills, and expressive language. Findings from this study provide an examination of the relationship between superior longitudinal fasciculus integrity and children’s neuropsychological abilities that can be useful in monitoring pediatric neurological diseases. PMID:24556549

  1. Double-letter processing in surface dyslexia and dysgraphia following a left temporal lesion: A multimodal neuroimaging study.

    PubMed

    Tomasino, Barbara; Marin, Dario; Maieron, Marta; D'Agostini, Serena; Fabbro, Franco; Skrap, Miran; Luzzatti, Claudio

    2015-12-01

    Neuropsychological data about acquired impairments in reading and writing provide a strong basis for the theoretical framework of the dual-route models. The present study explored the functional neuroanatomy of the reading and spelling processing system. We describe the reading and writing performance of patient CF, an Italian native speaker who developed an extremely selective reading and spelling deficit (his spontaneous speech, oral comprehension, repetition and oral picture naming were almost unimpaired) in processing double letters associated with surface dyslexia and dysgraphia, following a tumor in the left temporal lobe. In particular, the majority of CF's errors in spelling were phonologically plausible substitutions, errors concerning letter numerosity of consonants, and syllabic phoneme-to-grapheme conversion (PGC) errors. A similar pattern of impairment also emerged in his reading behavior, with a majority of lexical stress errors (the only possible type of surface reading errors in the Italian language, due the extreme regularity of print-to-sound correspondence). CF's neuropsychological profile was combined with structural neuroimaging data, fiber tracking, and functional maps and compared to that of healthy control participants. We related CF's deficit to a dissociation between impaired ventral/lexical route (as evidenced by a fractional anisotropy - FA decrease along the inferior fronto-occipital fasciculus - IFOF) and relatively preserved dorsal/phonological route (as evidenced by a rather full integrity of the superior longitudinal fasciculus - SLF). In terms of functional processing, the lexical-semantic ventral route network was more activated in controls than in CF, while the network supporting the dorsal route was shared by CF and the control participants. Our results are discussed within the theoretical framework of dual-route models of reading and spelling, emphasize the importance of the IFOF both in lexical reading and spelling, and offer a better comprehension of the neurological and functional substrates involved in written language and, in particular, in surface dyslexia and dysgraphia and in doubling/de-doubling consonant sounds and letters. PMID:26407482

  2. Does the Left Inferior Longitudinal Fasciculus Play a Role in Language? A Brain Stimulation Study

    ERIC Educational Resources Information Center

    Mandonnet, Emmanuel; Nouet, Aurelien; Gatignol, Peggy; Capelle, Laurent; Duffau, Hugues

    2007-01-01

    Although advances in diffusion tensor imaging have enabled us to better study the anatomy of the inferior longitudinal fasciculus (ILF), its function remains poorly understood. Recently, it was suggested that the subcortical network subserving the language semantics could be constituted, in parallel with the inferior occipitofrontal fasciculus, by…

  3. Does the Left Inferior Longitudinal Fasciculus Play a Role in Language? A Brain Stimulation Study

    ERIC Educational Resources Information Center

    Mandonnet, Emmanuel; Nouet, Aurelien; Gatignol, Peggy; Capelle, Laurent; Duffau, Hugues

    2007-01-01

    Although advances in diffusion tensor imaging have enabled us to better study the anatomy of the inferior longitudinal fasciculus (ILF), its function remains poorly understood. Recently, it was suggested that the subcortical network subserving the language semantics could be constituted, in parallel with the inferior occipitofrontal fasciculus, by…

  4. Reading impairment in a patient with missing arcuate fasciculus

    PubMed Central

    Rauschecker, Andreas M.; Deutsch, Gayle K.; Ben-Shachar, Michal; Schwartzman, Armin; Perry, Lee M.; Dougherty, Robert F.

    2009-01-01

    We describe the case of a child (“S”) who was treated with radiation therapy at age 5 for a recurrent malignant brain tumor. Radiation successfully abolished the tumor but caused radiation-induced tissue necrosis, primarily affecting cerebral white matter. S was introduced to us at age 15 because of her profound dyslexia. We assessed cognitive abilities and performed diffusion tensor imaging (DTI) to measure cerebral white matter pathways. Diffuse white matter differences were evident in T1-weighted, T2-weighted, diffusion anisotropy, and mean diffusivity measures in S compared to a group of 28 normal female controls. In addition, we found specific white matter pathway deficits by comparing tensor orientation directions in S’s brain with those of the control brains. While her principal diffusion direction maps appeared consistent with those of controls over most of the brain, there were tensor orientation abnormalities in the fiber tracts that form the superior longitudinal fasciculus (SLF) in both hemispheres. Tractography analysis indicated that the left and right arcuate fasciculus (AF), as well as other tracts within the SLF, were missing in S. Other major white matter tracts, such as the corticospinal and inferior occipitofrontal pathways, were intact. Functional MRI measurements indicated left-hemisphere dominanance for language with a normal activation pattern. Despite the left AF abnormality, S had preserved oral language with average sentence repetition skills. In addition to profound dyslexia, S exhibited visuospatial, calculation, and rapid naming deficits and was impaired in both auditory and spatial working memory. We propose that the reading and visuospatial deficits were due to the abnormal left and right SLF pathways, respectively. These results advance our understanding of the functional significance of the SLF and are the first to link radiation necrosis with selective damage to a specific set of fiber tracts. PMID:18775735

  5. Superior longitudinal fasciculus and language functioning in healthy aging.

    PubMed

    Madhavan, Kiely M; McQueeny, Tim; Howe, Steven R; Shear, Paula; Szaflarski, Jerzy

    2014-05-01

    Structural deterioration of brain tissue in older adults is thought to be responsible for the majority of age-related cognitive decline. Disruption of widespread cortical networks due to a loss of axonal integrity may also play an important role. Research examining correlations between structural change and functional decline has focused heavily on working memory, processing speed, and executive processes while other aspects of cognition, such as language functioning, have received less attention. The current study aimed to determine whether age-related changes in the superior longitudinal fasciculus (SLF), are responsible for the deterioration in language functioning associated with age. Subjects included 112 right-handed volunteers (ages 19-76). For each subject, the SLF of the left hemisphere was reconstructed from diffusion tensor images (DTI). Mean fractional anisotropy (FA) values were extracted from parietal (SLFp) and temporal (SLFt) bundles. Language functioning was measured using the Peabody Picture Vocabulary Test (PPVT), Boston Naming Test (BNT), Controlled Oral Word Association Test (COWAT), and Semantic Fluency Test (SFT). Regression analyses revealed that males and females showed a different pattern of decline in FA across adulthood. For males, greater SLFt FA was significantly associated with increased COWAT performance, and there was a positive relationship between both age and SLFp FA with BNT scores. In females, greater SLFp FA was related to lower COWAT performance. Taken together, the results suggest that white matter integrity of the SLF follows a different pattern of decline in adulthood for males and females, and this decline differentially affects language functioning. PMID:24680744

  6. Correlating Function and Imaging Measures of the Medial Longitudinal Fasciculus

    PubMed Central

    Sakaie, Ken; Takahashi, Masaya; Remington, Gina; Wang, Xiaofeng; Conger, Amy; Conger, Darrel; Dimitrov, Ivan; Jones, Stephen; Frohman, Ashley; Frohman, Teresa; Sagiyama, Koji; Togao, Osamu

    2016-01-01

    Objective To test the validity of diffusion tensor imaging (DTI) measures of tissue injury by examining such measures in a white matter structure with well-defined function, the medial longitudinal fasciculus (MLF). Injury to the MLF underlies internuclear ophthalmoparesis (INO). Methods 40 MS patients with chronic INO and 15 healthy controls were examined under an IRB-approved protocol. Tissue integrity of the MLF was characterized by DTI parameters: longitudinal diffusivity (LD), transverse diffusivity (TD), mean diffusivity (MD) and fractional anisotropy (FA). Severity of INO was quantified by infrared oculography to measure versional disconjugacy index (VDI). Results LD was significantly lower in patients than in controls in the medulla-pons region of the MLF (p < 0.03). FA was also lower in patients in the same region (p < 0.0004). LD of the medulla-pons region correlated with VDI (R = -0.28, p < 0.05) as did FA in the midbrain section (R = 0.31, p < 0.02). Conclusions This study demonstrates that DTI measures of brain tissue injury can detect injury to a functionally relevant white matter pathway, and that such measures correlate with clinically accepted evaluation indices for INO. The results validate DTI as a useful imaging measure of tissue integrity. PMID:26800522

  7. [A case of post-traumatic medial longitudinal fasciculus syndrome].

    PubMed

    Takano, S; Endoh, M; Miyasaka, Y; Ohwada, T; Mukuno, K; Takagi, H

    1991-10-01

    Medial longitudinal fasciculus (MLF) syndrome recognized 2 days after a head injury is described. The patient was a 48-year-old man who had fallen from a ladder about 3m high. On his admission, scalp contusion on the left occipital area was noticed. Neurological examination revealed no neurological abnormalities except slightly disturbed consciousness. Plain skull X-ray films demonstrated a lineal skull fracture of the left occipital bone. Computed tomographic (CT) scans showed a slight subarachnoid hemorrhage within the bilateral sylvian fissures, but no parenchymal contusion in the brain stem was observed. On the 2nd day, when the patient regained full consciousness, impairment of adduction of the right eye and a fine nystagmus of the left eye on left lateral gaze were recognized. Convergence was intact. Right side MLF syndrome was diagnosed. This syndrome gradually disappeared followed by the initial improvement of adduction of the right eye, and the patient had completely recovered about 20 days after the head injury. Three major mechanisms leading to MLF syndrome caused by head injury are reported in the literature. They are: (1) primary brain stem injury, (2) secondary brainstem injury by trans-tentorial herniation, and (3) circulatory disturbance of perforating branches of the vertebro-basilar artery due to shearing force. In our case, the slightly disturbed consciousness at the time of the head injury indicates that this syndrome was not brought on by primary or secondary brain stem injury.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1944782

  8. Structural white-matter connections mediating distinct behavioral components of spatial neglect in right brain-damaged patients.

    PubMed

    Vaessen, Maarten J; Saj, Arnaud; Lovblad, Karl-Olof; Gschwind, Markus; Vuilleumier, Patrik

    2016-04-01

    Spatial neglect is a neuropsychological syndrome in which patients fail to perceive and orient to stimuli located in the space contralateral to the lesioned hemisphere. It is characterized by a wide heterogeneity in clinical symptoms which can be grouped into distinct behavioral components correlating with different lesion sites. Moreover, damage to white-matter (WM) fiber tracts has been suggested to disconnect brain networks that mediate different functions associated with spatial cognition and attention. However, it remains unclear what WM pathways are associated with functionally dissociable neglect components. In this study we examined nine patients with a focal right hemisphere stroke using a series of neuropsychological tests and diffusion tensor imaging (DTI) in order to disentangle the role of specific WM pathways in neglect symptoms. First, following previous work, the behavioral test scores of patients were factorized into three independent components reflecting perceptual, exploratory, and object-centered deficits in spatial awareness. We then examined the structural neural substrates of these components by correlating indices of WM integrity (fractional anisotropy) with the severity of deficits along each profile. Several locations in the right parietal and frontal WM correlated with neuropsychological scores. Fiber tracts projecting from these locations indicated that posterior parts of the superior longitudinal fasciculus (SLF), as well as nearby callosal fibers connecting ipsilateral and contralateral parietal areas, were associated with perceptual spatial deficits, whereas more anterior parts of SLF and inferior fronto-occipital fasciculus (IFOF) were predominantly associated with object-centered deficits. In addition, connections between frontal areas and superior colliculus were found to be associated with the exploratory deficits. Our results provide novel support to the view that neglect may result from disconnection lesions in distributed brain networks, but also extend these notions by highlighting the role of dissociable circuits in different functional components of the neglect syndrome. However these preliminary findings require replication with larger samples of patients. PMID:26922504

  9. Asymmetrical white matter networks for attending to global versus local features

    PubMed Central

    Chechlacz, Magdalena; Mantini, Dante; Gillebert, Celine R.; Humphreys, Glyn W.

    2015-01-01

    The ability to draw objects is a complex process depending on an array of cognitive mechanisms including routines for spatial coding, attention and the processing of both local and global features. Previous studies using both neuropsychological and neuroimaging data have reported hemispheric asymmetries in attending to local versus global features linked to a variety of cortical loci. However, it has not been examined to date whether such asymmetries exist at the level of white matter pathways sub-serving global/local attention. The current study provides a comprehensive analysis of brain-behaviour relationships in the processing of local versus global features based on data from a large cohort of sub-acute stroke patients (n = 248) and behavioural measures from a complex figure copy task. The data analysis used newly developed methods for automated delineation of stroke lesions combined with track-wise lesion deficits procedures. We found (i) that reproduction of local features in figure copying was supported by a neural network confined to the left hemisphere, consisting of cortical loci within parietal, occipital and insular lobes and interconnected by the inferior-fronto-occipital fasciculus (IFOF), and (ii) that global feature processing was associated with a right hemisphere network interconnected by the third branch of the superior longitudinal fasciculus and the long segment of the perisylvian network. The data support the argument that asymmetrical white matter disconnections within long–range association pathways predict poor complex figure drawing resulting from deficits in hierarchical representation. We conclude that hemispheric asymmetries in attending to local versus global features exist on the level of both cortical loci and the supporting white matter pathways. PMID:25727548

  10. Anatomical Properties of the Arcuate Fasciculus Predict Phonological and Reading Skills in Children

    ERIC Educational Resources Information Center

    Yeatman, Jason D.; Dougherty, Robert F.; Rykhlevskaia, Elena; Sherbondy, Anthony J.; Deutsch, Gayle K.; Wandell, Brian A.; Ben-Shachar, Michal

    2011-01-01

    For more than a century, neurologists have hypothesized that the arcuate fasciculus carries signals that are essential for language function; however, the relevance of the pathway for particular behaviors is highly controversial. The primary objective of this study was to use diffusion tensor imaging to examine the relationship between individual…

  11. Anatomical Properties of the Arcuate Fasciculus Predict Phonological and Reading Skills in Children

    ERIC Educational Resources Information Center

    Yeatman, Jason D.; Dougherty, Robert F.; Rykhlevskaia, Elena; Sherbondy, Anthony J.; Deutsch, Gayle K.; Wandell, Brian A.; Ben-Shachar, Michal

    2011-01-01

    For more than a century, neurologists have hypothesized that the arcuate fasciculus carries signals that are essential for language function; however, the relevance of the pathway for particular behaviors is highly controversial. The primary objective of this study was to use diffusion tensor imaging to examine the relationship between individual…

  12. Microstructural connectivity of the arcuate fasciculus in adolescents with high-functioning autism

    PubMed Central

    Fletcher, P. Thomas; Whitaker, Ross T.; Tao, Ran; DuBray, Molly B.; Froehlich, Alyson; Ravichandran, Caitlin; Alexander, Andrew L.; Bigler, Erin D.; Lange, Nicholas; Lainhart, Janet E.

    2010-01-01

    The arcuate fasciculus is a white matter fiber bundle of great importance in language. In this study, diffusion tensor imaging (DTI) was used to infer white matter integrity in the arcuate fasciculi of a group of subjects with high-functioning autism and a control group matched for age, handedness, IQ, and head size. The arcuate fasciculus for each subject was automatically extracted from the imaging data using a new volumetric DTI segmentation algorithm. The results showed a significant increase in mean diffusivity (MD) in the autism group, due mostly to an increase in the radial diffusivity (RD). A test of the lateralization of DTI measurements showed that both MD and fractional anisotropy (FA) were less lateralized in the autism group. These results suggest that white matter microstructure in the arcuate fasciculus is affected in autism and that the language specialization apparent in the left arcuate of healthy subjects is not as evident in autism, which may be related to poorer language functioning. PMID:20132894

  13. 'For the benefit of the people': the Dutch translation of the Fasciculus medicinae, Antwerp 1512.

    PubMed

    Coppens, Christian

    2009-01-01

    The article deals with the Dutch translation of the Fasciculus medicinae based on the Latin edition, Venice 1495, with the famous woodcuts created in 1494 for the Italian translation of the original Latin edition of 1491. The woodcuts are compared with the Venetian model. New features in the Antwerp edition include the Skeleton and the Zodiac Man, bot originally based on German models. The text also deals with other woodcuts in the Low Countries based on these Venetian illustrations. The Appendices provide a short title catalog of all the editions and translations based on the Venetian edition and a stemma. PMID:19642255

  14. Damage to the anterior arcuate fasciculus predicts non-fluent speech production in aphasia.

    PubMed

    Fridriksson, Julius; Guo, Dazhou; Fillmore, Paul; Holland, Audrey; Rorden, Chris

    2013-11-01

    Non-fluent aphasia implies a relatively straightforward neurological condition characterized by limited speech output. However, it is an umbrella term for different underlying impairments affecting speech production. Several studies have sought the critical lesion location that gives rise to non-fluent aphasia. The results have been mixed but typically implicate anterior cortical regions such as Broca's area, the left anterior insula, and deep white matter regions. To provide a clearer picture of cortical damage in non-fluent aphasia, the current study examined brain damage that negatively influences speech fluency in patients with aphasia. It controlled for some basic speech and language comprehension factors in order to better isolate the contribution of different mechanisms to fluency, or its lack. Cortical damage was related to overall speech fluency, as estimated by clinical judgements using the Western Aphasia Battery speech fluency scale, diadochokinetic rate, rudimentary auditory language comprehension, and executive functioning (scores on a matrix reasoning test) in 64 patients with chronic left hemisphere stroke. A region of interest analysis that included brain regions typically implicated in speech and language processing revealed that non-fluency in aphasia is primarily predicted by damage to the anterior segment of the left arcuate fasciculus. An improved prediction model also included the left uncinate fasciculus, a white matter tract connecting the middle and anterior temporal lobe with frontal lobe regions, including the pars triangularis. Models that controlled for diadochokinetic rate, picture-word recognition, or executive functioning also revealed a strong relationship between anterior segment involvement and speech fluency. Whole brain analyses corroborated the findings from the region of interest analyses. An additional exploratory analysis revealed that involvement of the uncinate fasciculus adjudicated between Broca's and global aphasia, the two most common kinds of non-fluent aphasia. In summary, the current results suggest that the anterior segment of the left arcuate fasciculus, a white matter tract that lies deep to posterior portions of Broca's area and the sensory-motor cortex, is a robust predictor of impaired speech fluency in aphasic patients, even when motor speech, lexical processing, and executive functioning are included as co-factors. Simply put, damage to those regions results in non-fluent aphasic speech; when they are undamaged, fluent aphasias result. PMID:24131592

  15. A Combined fMRI and DTI Examination of Functional Language Lateralization and Arcuate Fasciculus Structure: Effects of Degree versus Direction of Hand Preference

    ERIC Educational Resources Information Center

    Propper, Ruthe E.; O'Donnell, Lauren J.; Whalen, Stephen; Tie, Yanmei; Norton, Isaiah H.; Suarez, Ralph O.; Zollei, Lilla; Radmanesh, Alireza; Golby, Alexandra J.

    2010-01-01

    The present study examined the relationship between hand preference degree and direction, functional language lateralization in Broca's and Wernicke's areas, and structural measures of the arcuate fasciculus. Results revealed an effect of degree of hand preference on arcuate fasciculus structure, such that consistently-handed individuals,…

  16. Long-term proper name anomia after removal of the uncinate fasciculus.

    PubMed

    Papagno, Costanza; Casarotti, Alessandra; Comi, Alessandro; Pisoni, Alberto; Lucchelli, Federica; Bizzi, Alberto; Riva, Marco; Bello, Lorenzo

    2016-01-01

    A previous study reporting on 44 patients who underwent awake surgery for a left frontal or temporal glioma resection demonstrated the removal of the uncinate fasciculus to have consequences on language 3 months post-surgery. At this time-point, patients with a temporal glioma who had undergone uncinate removal showed the worst overall performance with a significant impairment in naming of famous faces and objects compared to patients without removal. Also, verbal fluency was mildly impaired. We report a longer-term follow-up (9-12 months) in a selected group of 17 patients (six female, age range 27-64) who did not suffer any tumour recurrence in this timeframe. MRI and DTI were performed before and after surgery. While verbal fluency on categorical cue and object naming recovered to the same level as before surgery, proper naming remained significantly impaired even after 12 months (P = 0.032) in patients with uncinate removal, demonstrating this structure to be crucial for that function and supporting the hypothesis that subcortical connectivity is relevant to allow plasticity. We thus argued that the left frontal and temporal poles connected by means of the uncinate fasciculus constitute a dedicated circuit for naming of unique entities. PMID:25348267

  17. Virtual dissection and comparative connectivity of the superior longitudinal fasciculus in chimpanzees and humans.

    PubMed

    Hecht, Erin E; Gutman, David A; Bradley, Bruce A; Preuss, Todd M; Stout, Dietrich

    2015-03-01

    Many of the behavioral capacities that distinguish humans from other primates rely on fronto-parietal circuits. The superior longitudinal fasciculus (SLF) is the primary white matter tract connecting lateral frontal with lateral parietal regions; it is distinct from the arcuate fasciculus, which interconnects the frontal and temporal lobes. Here we report a direct, quantitative comparison of SLF connectivity using virtual in vivo dissection of the SLF in chimpanzees and humans. SLF I, the superior-most branch of the SLF, showed similar patterns of connectivity between humans and chimpanzees, and was proportionally volumetrically larger in chimpanzees. SLF II, the middle branch, and SLF III, the inferior-most branch, showed species differences in frontal connectivity. In humans, SLF II showed greater connectivity with dorsolateral prefrontal cortex, whereas in chimps SLF II showed greater connectivity with the inferior frontal gyrus. SLF III was right-lateralized and proportionally volumetrically larger in humans, and human SLF III showed relatively reduced connectivity with dorsal premotor cortex and greater extension into the anterior inferior frontal gyrus, especially in the right hemisphere. These results have implications for the evolution of fronto-parietal functions including spatial attention to observed actions, social learning, and tool use, and are in line with previous research suggesting a unique role for the right anterior inferior frontal gyrus in the evolution of human fronto-parietal network architecture. PMID:25534109

  18. Pediatric traumatic brain injury: Language outcomes and their relationship to the arcuate fasciculus

    PubMed Central

    Liégeois, Frédérique J.; Mahony, Kate; Connelly, Alan; Pigdon, Lauren; Tournier, Jacques-Donald; Morgan, Angela T.

    2013-01-01

    Pediatric traumatic brain injury (TBI) may result in long-lasting language impairments alongside dysarthria, a motor-speech disorder. Whether this co-morbidity is due to the functional links between speech and language networks, or to widespread damage affecting both motor and language tracts, remains unknown. Here we investigated language function and diffusion metrics (using diffusion-weighted tractography) within the arcuate fasciculus, the uncinate fasciculus, and the corpus callosum in 32 young people after TBI (approximately half with dysarthria) and age-matched healthy controls (n = 17). Only participants with dysarthria showed impairments in language, affecting sentence formulation and semantic association. In the whole TBI group, sentence formulation was best predicted by combined corpus callosum and left arcuate volumes, suggesting this “dual blow” seriously reduces the potential for functional reorganisation. Word comprehension was predicted by fractional anisotropy in the right arcuate. The co-morbidity between dysarthria and language deficits therefore seems to be the consequence of multiple tract damage. PMID:23756046

  19. Bidirectional iterative parcellation of diffusion weighted imaging data: separating cortical regions connected by the arcuate fasciculus and extreme capsule.

    PubMed

    Patterson, Dianne K; Van Petten, Cyma; Beeson, Pélagie M; Rapcsak, Steven Z; Plante, Elena

    2014-11-15

    This paper introduces a Bidirectional Iterative Parcellation (BIP) procedure designed to identify the location and size of connected cortical regions (parcellations) at both ends of a white matter tract in diffusion weighted images. The procedure applies the FSL option "probabilistic tracking with classification targets" in a bidirectional and iterative manner. To assess the utility of BIP, we applied the procedure to the problem of parcellating a limited set of well-established gray matter seed regions associated with the dorsal (arcuate fasciculus/superior longitudinal fasciculus) and ventral (extreme capsule fiber system) white matter tracts in the language networks of 97 participants. These left hemisphere seed regions and the two white matter tracts, along with their right hemisphere homologues, provided an excellent test case for BIP because the resulting parcellations overlap and their connectivity via the arcuate fasciculi and extreme capsule fiber systems are well studied. The procedure yielded both confirmatory and novel findings. Specifically, BIP confirmed that each tract connects within the seed regions in unique, but expected ways. Novel findings included increasingly left-lateralized parcellations associated with the arcuate fasciculus/superior longitudinal fasciculus as a function of age and education. These results demonstrate that BIP is an easily implemented technique that successfully confirmed cortical connectivity patterns predicted in the literature, and has the potential to provide new insights regarding the architecture of the brain. PMID:25173414

  20. Psychopathic traits modulate microstructural integrity of right uncinate fasciculus in a community population

    PubMed Central

    Sobhani, Mona; Baker, Laura; Martins, Bradford; Tuvblad, Catherine; Aziz-Zadeh, Lisa

    2015-01-01

    Individuals with psychopathy possess emotional and behavioral abnormalities. Two neural regions, involved in behavioral control and emotion regulation, are often implicated: amygdala and ventromedial prefrontal cortex (VMPFC). Recently, in studies using adult criminal populations, reductions in microstructural integrity of the white matter connections (i.e., uncinate fasciculus (UF)) between these two neural regions have been discovered in criminals with psychopathy, supporting the notion of neural dysfunction in the amygdala–VMPFC circuit. Here, a young adult, community sample is used to assess whether psychopathic traits modulate microstructural integrity of UF, and whether this relationship is dependent upon levels of trait anxiety, which is sometimes used to distinguish subtypes of psychopathy. Results reveal a negative association between psychopathic traits and microstructural integrity of UF, supporting previous findings. However, no moderation of the relationship by trait anxiety was discovered. Findings provide further support for the notion of altered amygdala–VMPFC connectivity in association with higher psychopathic traits. PMID:26106525

  1. Interpersonal traits of psychopathy linked to reduced integrity of the uncinate fasciculus.

    PubMed

    Wolf, Richard C; Pujara, Maia S; Motzkin, Julian C; Newman, Joseph P; Kiehl, Kent A; Decety, Jean; Kosson, David S; Koenigs, Michael

    2015-10-01

    Psychopathy is a personality disorder characterized by callous lack of empathy, impulsive antisocial behavior, and criminal recidivism. Here, we performed the largest diffusion tensor imaging (DTI) study of incarcerated criminal offenders to date (N = 147) to determine whether psychopathy severity is linked to the microstructural integrity of major white matter tracts in the brain. Consistent with the results of previous studies in smaller samples, we found that psychopathy was associated with reduced fractional anisotropy in the right uncinate fasciculus (UF; the major white matter tract connecting ventral frontal and anterior temporal cortices). We found no such association in the left UF or in adjacent frontal or temporal white matter tracts. Moreover, the right UF finding was specifically related to the interpersonal features of psychopathy (glib superficial charm, grandiose sense of self-worth, pathological lying, manipulativeness), rather than the affective, antisocial, or lifestyle features. These results indicate a neural marker for this key dimension of psychopathic symptomatology. PMID:26219745

  2. Diffusion Tensor Imaging Studies on Arcuate Fasciculus in Stroke Patients: A Review

    PubMed Central

    Jang, Sung Ho

    2013-01-01

    Aphasia is one of the most common and devastating sequelae of stroke. The arcuate fasciculus (AF), an important neural tract for language function, connects Broca’s and Wernicke’s areas. In this review article, previous diffusion tensor imaging (DTI) studies on the AF in stroke patients were reviewed with regard to the usefulness for diagnosis (seven studies), prediction of prognosis (two studies), and recovery of aphasia (three studies). Although scant studies on this topic have been conducted in stroke patients, DTI for the AF appears to provide useful information on the presence or severity of injury of the AF, prognosis prediction of aphasia, and recovery mechanisms of aphasia in stroke patients. Therefore, further DTI studies on these topics should be encouraged, especially studies on prognosis prediction and recovery mechanisms of aphasia. In addition, research on other neural tracts known to be involved in aphasia as well as the AF in both hemispheres should be encouraged. PMID:24198780

  3. Evidence of slow maturation of the superior longitudinal fasciculus in early childhood by diffusion tensor imaging.

    PubMed

    Zhang, Jiangyang; Evans, Alan; Hermoye, Laurent; Lee, Seung-Koo; Wakana, Setsu; Zhang, Weihong; Donohue, Pamela; Miller, Michael I; Huang, Hao; Wang, Xiaoqing; van Zijl, Peter C M; Mori, Susumu

    2007-11-01

    While the majority of axonal organization is established by birth in mammalian brains, axonal wiring and pruning processes, as well as myelination, are known to extend to the postnatal periods, where environmental stimuli often play a major role. Normal axonal and myelin development of individual white matter tracts of human in this period is poorly understood and may have a major role in cognitive development of human. In this study, we applied diffusion tensor imaging and normalization-based population analyses to 44 preteen children and 30 adult images. We observed highly significant changes of fiber orientations at regions that correspond to the superior longitudinal fasciculus during the first 5 years. The result is attributed to slow axonal and/or myelin maturation of this tract, which is believed to be involved in language functions. PMID:17826183

  4. Is the term "fasciculus opticus cerebralis" more justifiable than the term "optic nerve"?

    PubMed

    Vojnikovi?, Bojo; Bajek, Snjezana; Bajek, Goran; Strenja-Lini?, Ines; Grubesi?, Aron

    2013-04-01

    The terminology of the optic nerve had already been changed three times, since 1895 until 1955 when the term "nervus opticus" was introduced in the "Terminologia Anatomica". Following our study we claim that, from the aspect of phylogenetic evolution of binocular vision development as well as optical embryogenesis where opticus is evidently presented as a product of diencephalic structures, the addition of the term "nervus" to opticus is not adequate and justified. From the clinical aspect the term "nervus opticus" is also inadequate, both as a "nerve" that has no functional regenerative properties, unlike other cranial nerves, as well as from a pedagogical and didactical aspect of educating future physicians. We suggest that the term "Fasciculus Opticus Cerebralis" should be used as it much better explains the origin as well as its affiliation to the central nervous system. PMID:23837214

  5. Psychopathic traits modulate microstructural integrity of right uncinate fasciculus in a community population.

    PubMed

    Sobhani, Mona; Baker, Laura; Martins, Bradford; Tuvblad, Catherine; Aziz-Zadeh, Lisa

    2015-01-01

    Individuals with psychopathy possess emotional and behavioral abnormalities. Two neural regions, involved in behavioral control and emotion regulation, are often implicated: amygdala and ventromedial prefrontal cortex (VMPFC). Recently, in studies using adult criminal populations, reductions in microstructural integrity of the white matter connections (i.e., uncinate fasciculus (UF)) between these two neural regions have been discovered in criminals with psychopathy, supporting the notion of neural dysfunction in the amygdala-VMPFC circuit. Here, a young adult, community sample is used to assess whether psychopathic traits modulate microstructural integrity of UF, and whether this relationship is dependent upon levels of trait anxiety, which is sometimes used to distinguish subtypes of psychopathy. Results reveal a negative association between psychopathic traits and microstructural integrity of UF, supporting previous findings. However, no moderation of the relationship by trait anxiety was discovered. Findings provide further support for the notion of altered amygdala-VMPFC connectivity in association with higher psychopathic traits. PMID:26106525

  6. Increased Brain White Matter Axial Diffusivity Associated with Fatigue, Pain and Hyperalgesia in Gulf War Illness

    PubMed Central

    Rayhan, Rakib U.; Stevens, Benson W.; Timbol, Christian R.; Adewuyi, Oluwatoyin; Walitt, Brian; VanMeter, John W.; Baraniuk, James N.

    2013-01-01

    Background Gulf War exposures in 1990 and 1991 have caused 25% to 30% of deployed personnel to develop a syndrome of chronic fatigue, pain, hyperalgesia, cognitive and affective dysfunction. Methods Gulf War veterans (n?=?31) and sedentary veteran and civilian controls (n?=?20) completed fMRI scans for diffusion tensor imaging. A combination of dolorimetry, subjective reports of pain and fatigue were correlated to white matter diffusivity properties to identify tracts associated with symptom constructs. Results Gulf War Illness subjects had significantly correlated fatigue, pain, hyperalgesia, and increased axial diffusivity in the right inferior fronto-occipital fasciculus. ROC generated thresholds and subsequent binary regression analysis predicted CMI classification based upon axial diffusivity in the right inferior fronto-occipital fasciculus. These correlates were absent for controls in dichotomous regression analysis. Conclusion The right inferior fronto-occipital fasciculus may be a potential biomarker for Gulf War Illness. This tract links cortical regions involved in fatigue, pain, emotional and reward processing, and the right ventral attention network in cognition. The axonal neuropathological mechanism(s) explaining increased axial diffusivity may account for the most prominent symptoms of Gulf War Illness. PMID:23526988

  7. The White Matter Microintegrity Alterations of Neocortical and Limbic Association Fibers in Major Depressive Disorder and Panic Disorder: The Comparison.

    PubMed

    Lai, Chien-Han; Wu, Yu-Te

    2016-03-01

    The studies regarding to the comparisons between major depressive disorder (MDD) and panic disorder (PD) in the microintegrity of white matter (WM) are uncommon. Therefore, we tried to a way to classify the MDD and PD.Fifty-three patients with 1st-episode medication-naive PD, 54 healthy controls, and 53 patients with 1st-episode medication-naive MDD were enrolled in this study. The controls and patients were matched for age, gender, education, and handedness. The diffusion tensor imaging scanning was also performed. The WM microintegrity was analyzed and compared between 3 groups of participants (ANOVA analysis) with age and gender as covariates.The MDD group had lower WM microintegrity than the PD group in the left anterior thalamic radiation, left uncinate fasciculus, left inferior fronto-occipital fasciculus, and bilateral corpus callosum. The MDD group had reductions in the microintegrity when compared to controls in the bilateral superior longitudinal fasciculi, inferior longitudinal fasciculi, inferior fronto-occipital fasciculi, and corpus callosum. The PD group had lower microintegrity in bilateral superior longitudinal fasciculi and left inferior fronto-occipital fasciculus when compared to controls.The widespread pattern of microintegrity alterations in fronto-limbic WM circuit for MDD was different from restrictive pattern of alterations for PD. PMID:26945417

  8. The White Matter Microintegrity Alterations of Neocortical and Limbic Association Fibers in Major Depressive Disorder and Panic Disorder

    PubMed Central

    Lai, Chien-Han; Wu, Yu-Te

    2016-01-01

    Abstract The studies regarding to the comparisons between major depressive disorder (MDD) and panic disorder (PD) in the microintegrity of white matter (WM) are uncommon. Therefore, we tried to a way to classify the MDD and PD. Fifty-three patients with 1st-episode medication-naive PD, 54 healthy controls, and 53 patients with 1st-episode medication-naive MDD were enrolled in this study. The controls and patients were matched for age, gender, education, and handedness. The diffusion tensor imaging scanning was also performed. The WM microintegrity was analyzed and compared between 3 groups of participants (ANOVA analysis) with age and gender as covariates. The MDD group had lower WM microintegrity than the PD group in the left anterior thalamic radiation, left uncinate fasciculus, left inferior fronto-occipital fasciculus, and bilateral corpus callosum. The MDD group had reductions in the microintegrity when compared to controls in the bilateral superior longitudinal fasciculi, inferior longitudinal fasciculi, inferior fronto-occipital fasciculi, and corpus callosum. The PD group had lower microintegrity in bilateral superior longitudinal fasciculi and left inferior fronto-occipital fasciculus when compared to controls. The widespread pattern of microintegrity alterations in fronto-limbic WM circuit for MDD was different from restrictive pattern of alterations for PD. PMID:26945417

  9. White matter and reading deficits after pediatric traumatic brain injury: A diffusion tensor imaging study

    PubMed Central

    Johnson, Chad Parker; Juranek, Jenifer; Swank, Paul R.; Kramer, Larry; Cox, Charles S.; Ewing-Cobbs, Linda

    2015-01-01

    Pediatric traumatic brain injury often results in significant long-term deficits in mastery of reading ability. This study aimed to identify white matter pathways that, when damaged, predicted reading deficits in children. Based on the dual-route model of word reading, we predicted that integrity of the inferior fronto-occipital fasciculus would be related to performance in sight word identification while integrity of the superior longitudinal fasciculus would be related to performance in phonemic decoding. Reading fluency and comprehension were hypothesized to relate to the superior longitudinal fasciculus, inferior fronto-occipital fasciculus, and cingulum bundle. The connectivity of white matter pathways was used to predict reading deficits in children aged 6 to 16 years with traumatic brain injury (n = 29) and those with orthopedic injury (n = 27) using tract-based spatial statistics. Results showed that children with traumatic brain injury and reduced microstructural integrity of the superior longitudinal fasciculus demonstrated reduced word-reading ability on sight word and phonemic decoding tasks. Additionally, children with traumatic brain injury and microstructural changes involving the cingulum bundle demonstrated reduced reading fluency. Results support the association of a dorsal pathway via the superior longitudinal fasciculus with both sight word reading and phonemic decoding. No association was identified between the inferior fronto-occipital fasciculus and sight word reading or phonemic decoding. Reading fluency was associated with the integrity of the cingulum bundle. These findings support dissociable pathways predicting word reading and fluency using Diffusion Tensor Imaging and provide additional information for developing models of acquired reading deficits by specifying areas of brain damage which may predict reading deficits following recovery from the acute phase of TBI. PMID:26740920

  10. Detection of the arcuate fasciculus in congenital amusia depends on the tractography algorithm

    PubMed Central

    Chen, Joyce L.; Kumar, Sukhbinder; Williamson, Victoria J.; Scholz, Jan; Griffiths, Timothy D.; Stewart, Lauren

    2015-01-01

    The advent of diffusion magnetic resonance imaging (MRI) allows researchers to virtually dissect white matter fiber pathways in the brain in vivo. This, for example, allows us to characterize and quantify how fiber tracts differ across populations in health and disease, and change as a function of training. Based on diffusion MRI, prior literature reports the absence of the arcuate fasciculus (AF) in some control individuals and as well in those with congenital amusia. The complete absence of such a major anatomical tract is surprising given the subtle impairments that characterize amusia. Thus, we hypothesize that failure to detect the AF in this population may relate to the tracking algorithm used, and is not necessarily reflective of their phenotype. Diffusion data in control and amusic individuals were analyzed using three different tracking algorithms: deterministic and probabilistic, the latter either modeling two or one fiber populations. Across the three algorithms, we replicate prior findings of a left greater than right AF volume, but do not find group differences or an interaction. We detect the AF in all individuals using the probabilistic 2-fiber model, however, tracking failed in some control and amusic individuals when deterministic tractography was applied. These findings show that the ability to detect the AF in our sample is dependent on the type of tractography algorithm. This raises the question of whether failure to detect the AF in prior studies may be unrelated to the underlying anatomy or phenotype. PMID:25653637

  11. Diffusivity of the uncinate fasciculus in heroin users relates to their levels of anxiety

    PubMed Central

    Wong, N M L; Cheung, S-H; Chan, C C H; Zeng, H; Liu, Y-P; So, K-F; Lee, T M C

    2015-01-01

    Heroin use is closely associated with emotional dysregulation, which may explain its high comorbidity with disorders such as anxiety and depression. However, the understanding of the neurobiological etiology of the association between heroin use and emotional dysregulation is limited. Previous studies have suggested an impact of heroin on diffusivity in white matter involving the emotional regulatory system, but the specificity of this finding remains to be determined. Therefore, this study investigated the association between heroin use and diffusivity of white matter tracts in heroin users and examined whether the tracts were associated with their elevated anxiety and depression levels. A sample of 26 right-handed male abstinent heroin users (25 to 42 years of age) and 32 matched healthy controls (19 to 55 years of age) was recruited for this study. Diffusion tensor imaging data were collected, and their levels of anxiety and depression were assessed using the Hospital Anxiety and Depression Scale. Our findings indicated that heroin users exhibited higher levels of anxiety and depression, but the heroin use-associated left uncinate fasciculus was only related to their anxiety level, suggesting that association between heroin and anxiety has an incremental organic basis but that for depression could be a threshold issue. This finding improves our understanding of heroin addiction and its comorbid affective disorder and facilitates future therapeutic development. PMID:25918991

  12. The vertical occipital fasciculus: A century of controversy resolved by in vivo measurements

    PubMed Central

    Yeatman, Jason D.; Weiner, Kevin S.; Pestilli, Franco; Rokem, Ariel; Mezer, Aviv; Wandell, Brian A.

    2014-01-01

    The vertical occipital fasciculus (VOF) is the only major fiber bundle connecting dorsolateral and ventrolateral visual cortex. Only a handful of studies have examined the anatomy of the VOF or its role in cognition in the living human brain. Here, we trace the contentious history of the VOF, beginning with its original discovery in monkey by Wernicke (1881) and in human by Obersteiner (1888), to its disappearance from the literature, and recent reemergence a century later. We introduce an algorithm to identify the VOF in vivo using diffusion-weighted imaging and tractography, and show that the VOF can be found in every hemisphere (n = 74). Quantitative T1 measurements demonstrate that tissue properties, such as myelination, in the VOF differ from neighboring white-matter tracts. The terminations of the VOF are in consistent positions relative to cortical folding patterns in the dorsal and ventral visual streams. Recent findings demonstrate that these same anatomical locations also mark cytoarchitectonic and functional transitions in dorsal and ventral visual cortex. We conclude that the VOF is likely to serve a unique role in the communication of signals between regions on the ventral surface that are important for the perception of visual categories (e.g., words, faces, bodies, etc.) and regions on the dorsal surface involved in the control of eye movements, attention, and motion perception. PMID:25404310

  13. Axons from the medial habenular nucleus are topographically sorted in the fasciculus retroflexus.

    PubMed

    Ichijo, Hiroyuki; Toyama, Tomoko

    2015-09-01

    We generated transgenic mice lines with a construct consisting of the zif268/egr1 promoter and the gene for the normal long-life yellow fluorescent protein (Venus) with a membrane localization sequence. One of the lines exhibited topographic labeling in the medial habenular nucleus (MHb) during postnatal development, which confirmed the previous findings that the medial, lateral, and dorsal areas of MHb project to the ventral, dorsal, and lateral parts of the interpeduncular nucleus, respectively. In addition, the membranous localization of the labeling allowed us to observe spacial arrangement of the labeled axons in the fasciculus retroflexus (FR) in the transgenic mice. Here, we report topographic sorting of the MHb axons in the FR. At postnatal day (P) 5 and P10, the labeled axons from the medial MHb were fasciculated and ran through the narrow path in the core of the FR. At P24, the labeled axons from the medial and dorsal MHb were fasciculated and ran through the broad path in the FR core. No labeling occurred in the lateral MHb throughout development; correspondingly, parts of the FR core remained unlabeled. The results indicated that the axons from the medial and dorsal areas of the MHb are grouped together in the FR of this transgenic line and are sorted out from the axons from the lateral MHb. PMID:25145706

  14. Detection of the arcuate fasciculus in congenital amusia depends on the tractography algorithm.

    PubMed

    Chen, Joyce L; Kumar, Sukhbinder; Williamson, Victoria J; Scholz, Jan; Griffiths, Timothy D; Stewart, Lauren

    2015-01-01

    The advent of diffusion magnetic resonance imaging (MRI) allows researchers to virtually dissect white matter fiber pathways in the brain in vivo. This, for example, allows us to characterize and quantify how fiber tracts differ across populations in health and disease, and change as a function of training. Based on diffusion MRI, prior literature reports the absence of the arcuate fasciculus (AF) in some control individuals and as well in those with congenital amusia. The complete absence of such a major anatomical tract is surprising given the subtle impairments that characterize amusia. Thus, we hypothesize that failure to detect the AF in this population may relate to the tracking algorithm used, and is not necessarily reflective of their phenotype. Diffusion data in control and amusic individuals were analyzed using three different tracking algorithms: deterministic and probabilistic, the latter either modeling two or one fiber populations. Across the three algorithms, we replicate prior findings of a left greater than right AF volume, but do not find group differences or an interaction. We detect the AF in all individuals using the probabilistic 2-fiber model, however, tracking failed in some control and amusic individuals when deterministic tractography was applied. These findings show that the ability to detect the AF in our sample is dependent on the type of tractography algorithm. This raises the question of whether failure to detect the AF in prior studies may be unrelated to the underlying anatomy or phenotype. PMID:25653637

  15. Sex Differences of Uncinate Fasciculus Structural Connectivity in Individuals with Conduct Disorder

    PubMed Central

    Zhang, Jibiao; Gao, Junling; Shi, Huqing; Huang, Bingsheng; Wang, Xiang; Situ, Weijun; Cai, Weixiong; Yi, Jinyao; Zhu, Xiongzhao; Yao, Shuqiao

    2014-01-01

    Conduct disorder (CD) is one of the most common behavior disorders in adolescents, such as impulsivity, aggression, and running from school. Males are more likely to develop CD than females, and two previous diffusion tensor imaging (DTI) studies have demonstrated abnormal microstructural integrity in the uncinate fasciculus (UF) in boys with CD compared to a healthy control group. However, little is known about changes in the UF in females with CD. In this study, the UF was illustrated by tractography; then, the fractional anisotropy (FA), axial diffusivity, mean diffusion, radial diffusivity (RD), and the length and number of the UF fiber bundles were compared between male and female patients with CD and between female patients with CD and female healthy controls, as well as between males with CD and healthy males. We found that males with CD showed significantly higher FA of the bilateral UF and significantly lower RD of the left UF when comparing with females with CD. Meanwhile, significantly higher FA and lower RD of the bilateral UF were also found in boys with CD relative to the male healthy controls. Our results replicated previous reports that the microstructural integrity of the UF was abnormal in boys with CD. Additionally, our results demonstrated significant gender effects on the UF of patients with CD, which may indicate why boys have higher rates of conduct problems than girls. PMID:24829912

  16. Dissociable roles of the inferior longitudinal fasciculus and fornix in face and place perception.

    PubMed

    Hodgetts, Carl J; Postans, Mark; Shine, Jonathan P; Jones, Derek K; Lawrence, Andrew D; Graham, Kim S

    2015-01-01

    We tested a novel hypothesis, generated from representational accounts of medial temporal lobe (MTL) function, that the major white matter tracts converging on perirhinal cortex (PrC) and hippocampus (HC) would be differentially involved in face and scene perception, respectively. Diffusion tensor imaging was applied in healthy participants alongside an odd-one-out paradigm sensitive to PrC and HC lesions in animals and humans. Microstructure of inferior longitudinal fasciculus (ILF, connecting occipital and ventro-anterior temporal lobe, including PrC) and fornix (the main HC input/output pathway) correlated with accuracy on odd-one-out judgements involving faces and scenes, respectively. Similarly, blood oxygen level-dependent (BOLD) response in PrC and HC, elicited during oddity judgements, was correlated with face and scene oddity performance, respectively. We also observed associations between ILF and fornix microstructure and category-selective BOLD response in PrC and HC, respectively. These striking three-way associations highlight functionally dissociable, structurally instantiated MTL neurocognitive networks for complex face and scene perception. PMID:26319355

  17. Injury of the Arcuate Fasciculus in the Dominant Hemisphere in Patients With Mild Traumatic Brain Injury

    PubMed Central

    Jang, Sung Ho; Lee, Ah Young; Shin, So Min

    2016-01-01

    Abstract Little is known about injury of the arcuate fasciculus (AF) in patients with mild traumatic brain injury (TBI). We investigated injury of the AF in the dominant hemisphere in patients with mild TBI, using diffusion tensor tractography (DTT). We recruited 25 patients with injury of the left AF among 64 right-handed consecutive patients with mild TBI and 20 normal control subjects. DTTs of the left AF were reconstructed, and fractional anisotropy (FA), apparent diffusion coefficient (ADC), and fiber number of the AF were measured. Among 64 consecutive patients, 25 (39%) patients showed injury of the left AF. The patient group showed lower FA value and fiber number with higher ADC value than the control group (P < 0.05). On K-WAB evaluation, aphasia quotient and language quotient were 95.9 ± 4.1 (range 85–100) and 95.0 ± 5.4 (range 80–100), respectively. However, 23 (92.0%) of 25 patients complained of language-related symptoms after TBI; paraphasia in 12 (48.0%) patients, deficits of comprehension in 4 (16.0%) patients, deficits of speech production in 1 (4.0%) patient, and >2 language symptoms in 6 (24.0%) patients. We found that a significant number (39%) of patients with mild TBI had injury of the AF in the dominant hemisphere and these patients had mild language deficit. These results suggest that DTT could provide useful information in detecting injury of the AF and evaluation of the AF using DTT would be necessary even in the case of a patient with mild TBI who complains of mild language deficit. PMID:26945425

  18. Object Working Memory Performance Depends on Microstructure of the Frontal-Occipital Fasciculus

    PubMed Central

    Walsh, Megan; Montojo, Caroline A.; Sheu, Yi-Shin; Marchette, Steven A.; Harrison, Daniel M.; Newsome, Scott D.; Zhou, Feng; Shelton, Amy L.

    2011-01-01

    Abstract Re-entrant circuits involving communication between the frontal cortex and other brain areas have been hypothesized to be necessary for maintaining the sustained patterns of neural activity that represent information in working memory, but evidence has so far been indirect. If working memory maintenance indeed depends on such temporally precise and robust long-distance communication, then performance on a delayed recognition task should be highly dependent on the microstructural integrity of white-matter tracts connecting sensory areas with prefrontal cortex. This study explored the effect of variations in white-matter microstructure on working memory performance in two separate groups of participants: patients with multiple sclerosis and age- and sex-matched healthy adults. Functional magnetic resonance imaging was performed to reveal cortical regions involved in spatial and object working memory, which, in turn, were used to define specific frontal to extrastriate white-matter tracts of interest via diffusion tensor tractography. After factoring out variance due to age and the microstructure of a control tract (the corticospinal tract), the number of errors produced in the object working memory task was specifically related to the microstructure of the inferior frontal-occipital fasciculus. This result held for both groups, independently, providing a within-study replication with two different types of white-matter structural variability: multiple sclerosis–related damage and normal variation. The results demonstrate the importance of interactions between specific regions of the prefrontal cortex and sensory cortices for a nonspatial working memory task that preferentially activates those regions. PMID:22432421

  19. White matter alterations in temporal lobe epilepsy

    NASA Astrophysics Data System (ADS)

    Diniz, P. B.; Salmon, C. E.; Velasco, T. R.; Sakamoto, A. C.; Leite, J. P.; Santos, A. C.

    2011-03-01

    In This study, we used Fractional anisotropy (FA), mean diffusivity (D), parallel diffusivity (D//) and perpendicular diffusivity (D), to localize the regions where occur axonal lesion and demyelization. TBSS was applied to analyze the FA data. After, the regions with alteration were studied with D, D// and D maps. Patients exhibited widespread degradation of FA. With D, D// and D maps analysis we found alterations in corpus callosum, corticospinal tract, fornix, internal capsule, corona radiate, Sagittal stratum, cingulum, fronto-occipital fasciculus and uncinate fasciculus. Our results are consistent with the hypothesis that exist demyelization and axonal damage in patients with TLE.

  20. Structural alterations of the language connectome in children with specific language impairment.

    PubMed

    Vydrova, Rosa; Komarek, Vladimir; Sanda, Jan; Sterbova, Katalin; Jahodova, Alena; Maulisova, Alice; Zackova, Jitka; Reissigova, Jindra; Krsek, Pavel; Kyncl, Martin

    2015-12-01

    We evaluated brain white matter pathways associated with language processing in 37 children with specific language impairment aged 6-12years and 34 controls, matched for age, sex and handedness. Arcuate fascicle (AF), inferior fronto-occipital fascicle (IFOF), inferior longitudinal fascicle (ILF) and uncinate fascicle (UF) were identified using magnetic resonance diffusion tensor imaging (DTI). Diffusivity parameters and volume of the tracts were compared between the SLI and control group. Children with SLI showed decreased fractional anisotropy in all investigated tracts, increased mean diffusivity and radial diffusivity component in arcuate fascicle bilaterally, left IFOF and left ILF. Further, bilaterally increased volume of the ILF in children with SLI was found. We confirmed previous findings indicating deficient connectivity of the arcuate fascicle and as a novel finding, demonstrate abnormal development of the ventral language stream in patients with SLI. PMID:26609941

  1. Tract-based diffusion tensor imaging in patients with schizophrenia and their non-psychotic siblings.

    PubMed

    Boos, Heleen B M; Mandl, René C W; van Haren, Neeltje E M; Cahn, Wiepke; van Baal, G Caroline M; Kahn, René S; Hulshoff Pol, Hilleke E

    2013-04-01

    Structural brain abnormalities have consistently been found in patients with schizophrenia. Diffusion tensor imaging (DTI) has been shown to be a useful method to measure white matter (WM) integrity in this illness, but findings in the earlier disease stages are inconclusive. Moreover, the relationship between WM microstructure and the familial risk for developing schizophrenia remains unresolved. From 126 patients with schizophrenia, 123 of their non-psychotic siblings and 109 healthy control subjects, DTI images were acquired on a 1.5 T MRI scanner. Mean fractional anisotropy (FA) was compared along averaged WM tracts, computed for the genu, splenium, left and right uncinate fasciculus, cingulum, inferior fronto-occipital fasciculus, fornix, arcuate fasciculus, and inferior longitudinal fasciculus. Fractional anisotropy (FA) was assessed for its unique environmental and familial (possibly heritable) aspects associated with schizophrenia, using structural equation modeling for these white matter tracts. The results of this study show that young adult (mean age 26.7 years) patients with schizophrenia did not differ in mean FA from healthy controls along WM fibers; siblings of patients showed higher mean FA in the left and right arcuate fasciculus as compared to patients and controls. With increasing age, an excessive decline in mean FA was found in patients as compared to siblings and healthy controls in the genu, left uncinate fasciculus, left inferior fronto-occipital fasciculus, and left inferior longitudinal fasciculus. Moreover, symptom severity was negatively correlated to mean FA in the arcuate fasciculus bilaterally in patients with schizophrenia. In young adult patients with schizophrenia integrity of individual tract-based (corticocortical) fibers can (still) be within normal limits. However, changes in the arcuate fasciculus may be relevant to (the risk to develop) psychosis, while a general and widespread loss of fiber integrity may be related to illness progression. PMID:22841128

  2. Tract specific analysis in patients with sickle cell disease

    NASA Astrophysics Data System (ADS)

    Chai, Yaqiong; Coloigner, Julie; Qu, Xiaoping; Choi, Soyoung; Bush, Adam; Borzage, Matt; Vu, Chau; Lepore, Natasha; Wood, John

    2015-12-01

    Sickle cell disease (SCD) is a hereditary blood disorder in which the oxygen-carrying hemoglobin molecule in red blood cells is abnormal. It affects numerous people in the world and leads to a shorter life span, pain, anemia, serious infections and neurocognitive decline. Tract-Specific Analysis (TSA) is a statistical method to evaluate white matter alterations due to neurocognitive diseases, using diffusion tensor magnetic resonance images. Here, for the first time, TSA is used to compare 11 major brain white matter (WM) tracts between SCD patients and age-matched healthy subjects. Alterations are found in the corpus callosum (CC), the cortico-spinal tract (CST), inferior fronto-occipital fasciculus (IFO), inferior longitudinal fasciculus (ILF), superior longitudinal fasciculus (SLF), and uncinated fasciculus (UNC). Based on previous studies on the neurocognitive functions of these tracts, the significant areas found in this paper might be related to several cognitive impairments and depression, both of which are observed in SCD patients.

  3. Lower structural integrity of the uncinate fasciculus is associated with a history of child maltreatment and future psychological vulnerability to stress.

    PubMed

    Hanson, Jamie L; Knodt, Annchen R; Brigidi, Bartholomew D; Hariri, Ahmad R

    2015-11-01

    The experience of child maltreatment is a significant risk factor for the development of later internalizing disorders such as depression and anxiety. This risk is particularly heightened after exposure to additional, more contemporaneous stress. While behavioral evidence exists for such "stress sensitization," little is known about the mechanisms mediating such relationships, particularly within the brain. Here we report that the experience of child maltreatment independent of recent life stress, gender, and age is associated with reduced structural integrity of the uncinate fasciculus, a major white matter pathway between the amygdala and ventromedial prefrontal cortex, in young adults. We further demonstrate that individuals with lower uncinate fasciculus integrity at baseline who subsequently experience stressful life events report higher levels of internalizing symptomatology at follow-up. Our findings suggest a novel neurobiological mechanism linking child maltreatment with later internalizing symptoms, specifically altered structural connectivity within the brain's threat-detection and emotion-regulation circuitry. PMID:26535947

  4. Lower structural integrity of the uncinate fasciculus is associated with a history of child maltreatment and future psychological vulnerability to stress

    PubMed Central

    Hanson, Jamie L; Knodt, Annchen R; Brigidi, Bartholomew D.; Hariri, Ahmad R.

    2015-01-01

    The experience of child maltreatment is a significant risk factor for the development of later internalizing disorders such as depression and anxiety. This risk is particularly heightened after exposure to additional, more contemporaneous stress. While behavioral evidence exists for such “stress sensitization,” little is known about the mechanisms mediating such relationships, particularly within the brain. Here we report that the experience of child maltreatment independent of recent life stress, gender, and age is associated with reduced structural integrity of the uncinate fasciculus, a major white matter pathway between the amygdala and ventromedial prefrontal cortex, in young adults. We further demonstrate that individuals with lower uncinate fasciculus integrity at baseline who subsequently experience stressful life events report higher levels of internalizing symptomatology at follow-up. Our findings suggest a novel neurobiological mechanism linking child maltreatment with later internalizing symptoms, specifically altered structural connectivity within the brain’s threat-detection and emotion regulation circuitry. PMID:26535947

  5. Microstructure of the superior longitudinal fasciculus predicts stimulation-induced interference with on-line motor control.

    PubMed

    Rodríguez-Herreros, Borja; Amengual, Julià L; Gurtubay-Antolín, Ane; Richter, Lars; Jauer, Philipp; Erdmann, Christian; Schweikard, Achim; López-Moliner, Joan; Rodríguez-Fornells, Antoni; Münte, Thomas F

    2015-10-15

    A cortical visuomotor network, comprising the medial intraparietal sulcus (mIPS) and the dorsal premotor area (PMd), encodes the sensorimotor transformations required for the on-line control of reaching movements. How information is transmitted between these two regions and which pathways are involved, are less clear. Here, we use a multimodal approach combining repetitive transcranial magnetic stimulation (rTMS) and diffusion tensor imaging (DTI) to investigate whether structural connectivity in the 'reaching' circuit is associated to variations in the ability to control and update a movement. We induced a transient disruption of the neural processes underlying on-line motor adjustments by applying 1Hz rTMS over the mIPS. After the stimulation protocol, participants globally showed a reduction of the number of corrective trajectories during a reaching task that included unexpected visual perturbations. A voxel-based analysis revealed that participants exhibiting higher fractional anisotropy (FA) in the second branch of the superior longitudinal fasciculus (SLF II) suffered less rTMS-induced behavioral impact. These results indicate that the microstructural features of the white matter bundles within the parieto-frontal 'reaching' circuit play a prominent role when action reprogramming is interfered. Moreover, our study suggests that the structural alignment and cohesion of the white matter tracts might be used as a predictor to characterize the extent of motor impairments. PMID:26143205

  6. Differences in white matter reflect atypical developmental trajectory in autism: A Tract-based Spatial Statistics study?

    PubMed Central

    Bakhtiari, Reyhaneh; Zürcher, Nicole R.; Rogier, Ophélie; Russo, Britt; Hippolyte, Loyse; Granziera, Cristina; Araabi, Babak Nadjar; Nili Ahmadabadi, Majid; Hadjikhani, Nouchine

    2012-01-01

    Autism is a neurodevelopmental disorder in which white matter (WM) maturation is affected. We assessed WM integrity in 16 adolescents and 14 adults with high-functioning autism spectrum disorder (ASD) and in matched neurotypical controls (NT) using diffusion weighted imaging and Tract-based Spatial Statistics. Decreased fractional anisotropy (FA) was observed in adolescents with ASD in tracts involved in emotional face processing, language, and executive functioning, including the inferior fronto-occipital fasciculus and the inferior and superior longitudinal fasciculi. Remarkably, no differences in FA were observed between ASD and NT adults. We evaluated the effect of age on WM development across the entire age range. Positive correlations between FA values and age were observed in the right inferior fronto-occipital fasciculus, the left superior longitudinal fasciculus, the corpus callosum, and the cortical spinal tract of ASD participants, but not in NT participants. Our data underscore the dynamic nature of brain development in ASD, showing the presence of an atypical process of WM maturation, that appears to normalize over time and could be at the basis of behavioral improvements often observed in high-functioning autism. PMID:24179736

  7. Relations between white matter maturation and reaction time in childhood.

    PubMed

    Scantlebury, Nadia; Cunningham, Todd; Dockstader, Colleen; Laughlin, Suzanne; Gaetz, William; Rockel, Conrad; Dickson, Jolynn; Mabbott, Donald

    2014-01-01

    White matter matures with age and is important for the efficient transmission of neuronal signals. Consequently, white matter growth may underlie the development of cognitive processes important for learning, including the speed of information processing. To dissect the relationship between white matter structure and information processing speed, we administered a reaction time task (finger abduction in response to visual cue) to 27 typically developing, right-handed children aged 4 to 13. Magnetoencephalography and Diffusion Tensor Imaging were used to delineate white matter connections implicated in visual-motor information processing. Fractional anisotropy (FA) and radial diffusivity (RD) of the optic radiation in the left hemisphere, and FA and mean diffusivity (MD) of the optic radiation in the right hemisphere changed significantly with age. MD and RD decreased with age in the right inferior fronto-occipital fasciculus, and bilaterally in the cortico-spinal tracts. No age-related changes were evident in the inferior longitudinal fasciculus. FA of the cortico-spinal tract in the left hemisphere and MD of the inferior fronto-occipital fasciculus of the right hemisphere contributed uniquely beyond the effect of age in accounting for reaction time performance of the right hand. Our findings support the role of white matter maturation in the development of information processing speed. PMID:24168858

  8. Sustained attention is associated with right superior longitudinal fasciculus and superior parietal white matter microstructure in children.

    PubMed

    Klarborg, Brith; Skak Madsen, Kathrine; Vestergaard, Martin; Skimminge, Arnold; Jernigan, Terry L; Baaré, William F C

    2013-12-01

    Sustained attention develops during childhood and has been linked to the right fronto-parietal cortices in functional imaging studies; however, less is known about its relation to white matter (WM) characteristics. Here we investigated whether the microstructure of the WM underlying and connecting the right fronto-parietal cortices was associated with sustained attention performance in a group of 76 typically developing children aged 7-13 years. Sustained attention was assessed using a rapid visual information processing paradigm. The two behavioral measures of interest were the sensitivity index d' and the coefficient of variation in reaction times (RTCV ). Diffusion-weighted imaging was performed. Mean fractional anisotropy (FA) was extracted from the WM underlying right dorsolateral prefrontal (DLPFC) and parietal cortex (PC), and the right superior longitudinal fasciculus (SLF), as well as equivalent anatomical regions-of-interest (ROIs) in the left hemisphere and mean global WM FA. When analyzed collectively, right hemisphere ROIs FA was significantly associated with d' independently of age. Follow-up analyses revealed that only FA of right SLF and the superior part of the right PC contributed significantly to this association. RTCV was significantly associated with right superior PC FA, but not with right SLF FA. Observed associations remained significant after controlling for FA of equivalent left hemisphere ROIs or global mean FA. In conclusion, better sustained attention performance was associated with higher FA of WM in regions connecting right frontal and parietal cortices. Further studies are needed to clarify to which extent these associations are driven by maturational processes, stable characteristics and/or experience. PMID:22806938

  9. Secure attachment status is associated with white matter integrity in healthy young adults.

    PubMed

    Serra, Mauro; De Pisapia, Nicola; Rigo, Paola; Papinutto, Nico; Jager, Justin; Bornstein, Marc H; Venuti, Paola

    2015-12-16

    The present study investigates associations between security of attachment in the mother-child relationship and patterns of brain connectivity in young adults. We hypothesized that secure attachment would relate to more efficient connectivity in white matter association fibers due to increased myelination. Attachment security was measured in 53 young adults using the Kerns Security Scale; anatomical information was acquired using diffusion tensor imaging. Higher fractional anisotropy, an index of directionality of diffusion, related to security of attachment in four left-hemisphere white matter association fibers (uncinate fasciculus, cingulum, superior longitudinal fasciculus, and inferior fronto-occipital fasciculus). As expected, this result was mainly ascribable to increased myelination, which has been independently associated with attachment security. Security of attachment may have an identifiable biological basis. Our research demonstrates the feasibility of coupling neuroimaging tools with clinical investigation. PMID:26559724

  10. Cerebral white matter deficiencies in pedophilic men.

    PubMed

    Cantor, James M; Kabani, Noor; Christensen, Bruce K; Zipursky, Robert B; Barbaree, Howard E; Dickey, Robert; Klassen, Philip E; Mikulis, David J; Kuban, Michael E; Blak, Thomas; Richards, Blake A; Hanratty, M Katherine; Blanchard, Ray

    2008-02-01

    The present investigation sought to identify which brain regions distinguish pedophilic from nonpedophilic men, using unbiased, automated analyses of the whole brain. T1-weighted magnetic resonance images (MRIs) were acquired from men who demonstrated illegal or clinically significant sexual behaviors or interests (n = 65) and from men who had histories of nonsexual offenses but no sexual offenses (n = 62). Sexual interest in children was assessed by participants' admissions of pedophilic interest, histories of committing sexual offenses against children, and psychophysiological responses in the laboratory to erotic stimuli depicting children or adults. Automated parcellation of the MRIs revealed significant negative associations between pedophilia and white matter volumes of the temporal and parietal lobes bilaterally. Voxel-based morphometry corroborated the associations and indicated that the regions of lower white matter volumes followed, and were limited to, two major fiber bundles: the superior fronto-occipital fasciculus and the right arcuate fasciculus. No significant differences were found in grey matter or in cerebrospinal fluid (CSF). Because the superior fronto-occipital and arcuate fasciculi connect the cortical regions that respond to sexual cues, these results suggest (1) that those cortical regions operate as a network for recognizing sexually relevant stimuli and (2) that pedophilia results from a partial disconnection within that network. PMID:18039544

  11. Lower white matter microstructure in the superior longitudinal fasciculus is associated with increased response time variability in adults with attention-deficit/hyperactivity disorder

    PubMed Central

    Wolfers, Thomas; Onnink, A. Marten H.; Zwiers, Marcel P.; Arias-Vasquez, Alejandro; Hoogman, Martine; Mostert, Jeanette C.; Kan, Cornelis C.; Slaats-Willemse, Dorine; Buitelaar, Jan K.; Franke, Barbara

    2015-01-01

    Background Response time variability (RTV) is consistently increased in patients with attention-deficit/hyperactivity disorder (ADHD). A right-hemispheric frontoparietal attention network model has been implicated in these patients. The 3 main connecting fibre tracts in this network, the superior longitudinal fasciculus (SLF), inferior longitudinal fasciculus (ILF) and the cingulum bundle (CB), show microstructural abnormalities in patients with ADHD. We hypothesized that the microstructural integrity of the 3 white matter tracts of this network are associated with ADHD and RTV. Methods We examined RTV in adults with ADHD by modelling the reaction time distribution as an exponentially modified Gaussian (ex-Gaussian) function with the parameters ?, ? and ?, the latter of which has been attributed to lapses of attention. We assessed adults with ADHD and healthy controls using a sustained attention task. Diffusion tensor imaging–derived fractional anisotropy (FA) values were determined to quantify bilateral microstructural integrity of the tracts of interest. Results We included 100 adults with ADHD and 96 controls in our study. Increased ? was associated with ADHD diagnosis and was linked to symptoms of inattention. An inverse correlation of ? with mean FA was seen in the right SLF of patients with ADHD, but no direct association between the mean FA of the 6 regions of interest with ADHD could be observed. Limitations Regions of interest were defined a priori based on the attentional network model for ADHD and thus we might have missed effects in other networks. Conclusion This study suggests that reduced microstructural integrity of the right SLF is associated with elevated ? in patients with ADHD. PMID:26079698

  12. Horizontal portion of arcuate fasciculus fibers track to pars opercularis, not pars triangularis, in right and left hemispheres: A DTI study

    PubMed Central

    Kaplan, Elina; Naeser, Margaret A.; Martin, Paula I.; Ho, Michael; Wang, Yunyan; Baker, Errol; Pascual-Leone, Alvaro

    2010-01-01

    The arcuate fasciculus (AF) is a white matter pathway traditionally considered to connect left Broca’s area with posterior language zones. We utilized diffusion tensor imaging (DTI) in eight healthy subjects (5M) to track pathways in the horizontal mid-portion of the AF (hAF) to subregions of Broca’s area - pars triangularis (PTr) and pars opercularis (POp); and to ventral premotor cortex (vPMC) in the right and left hemispheres (RH, LH). These pathways have previously been studied in the LH, but not in the RH. Only 1/8 subjects showed fiber tracts between PTr and hAF in the RH (also, only 1/8 in the LH). In contrast to PTr, 5/8 subjects showed fiber tracts between POp and hAF in the RH (8/8 in the LH). Fiber tracts for vPMC were similar to those of POp, where 7/8 subjects showed fiber tracts between vPMC and hAF in the RH (8/8 in the LH). Our designated hAF could have included some of the superior longitudinal fasciculus (SLF) III, because it is difficult to separate the two fiber bundles. The SLF III has been previously reported to connect supramarginal gyrus with POp and vPMC in the LH. Thus, although the present DTI study showed almost no pathways between PTr and hAF in the RH (and in the LH), robust pathways were observed between POp and/or vPMC with hAF in the RH (and in LH). These results replicate previous studies for the LH, but are new, for the RH. They could contribute to better understanding of recovery in aphasia. PMID:20438853

  13. Independent contribution of individual white matter pathways to language function in pediatric epilepsy patients

    PubMed Central

    Paldino, Michael J.; Hedges, Kara; Zhang, Wei

    2014-01-01

    Background and purpose Patients with epilepsy and malformations of cortical development (MCDs) are at high risk for language and other cognitive impairment. Specific impairments, however, are not well correlated with the extent and locale of dysplastic cortex; such findings highlight the relevance of aberrant cortico-cortical interactions, or connectivity, to the clinical phenotype. The goal of this study was to determine the independent contribution of well-described white matter pathways to language function in a cohort of pediatric patients with epilepsy. Materials and methods Patients were retrospectively identified from an existing database of pediatric epilepsy patients with the following inclusion criteria: 1. diagnosis of MCDs, 2. DTI performed at 3 T, and 3. language characterized by a pediatric neurologist. Diffusion Toolkit and Trackvis (http://www.trackvis.org) were used for segmentation and analysis of the following tracts: corpus callosum, corticospinal tracts, inferior longitudinal fasciculi (ILFs), inferior fronto-occipital fasciculi (IFOFs), uncinate fasciculi (UFs), and arcuate fasciculi (AFs). Mean diffusivity (MD) and fractional anisotropy (FA) were calculated for each tract. Wilcoxon rank sum test (corrected for multiple comparisons) was used to assess potential differences in tract parameters between language-impaired and language-intact patients. In a separate analysis, a machine learning algorithm (random forest approach) was applied to measure the independent contribution of the measured diffusion parameters for each tract to the clinical phenotype (language impairment). In other words, the importance of each tract parameter was measured after adjusting for the contribution of all other tracts. Results Thirty-three MCD patients were included (age range: 3–18 years). Twenty-one patients had intact language, twelve had language impairment. All tracts were identified bilaterally in all patients except for the AF, which was not identified on the right in 10 subjects and not identified on the left in 11 subjects. MD and/or FA within the left AF, UF, ILF, and IFOF differed between language-intact and language-impaired groups. However, only parameters related to the left uncinate, inferior fronto-occipital, and arcuate fasciculi were independently associated with the clinical phenotype. Conclusions Scalar metrics derived from the left uncinate, inferior fronto-occipital, and arcuate fasciculi were independently associated with language function. These results support the importance of these pathways in human language function in patients with MCDs. PMID:25379446

  14. Decreased and Increased Anisotropy along Major Cerebral White Matter Tracts in Preterm Children and Adolescents

    PubMed Central

    Ben-Shachar, Michal; Feldman, Heidi M.

    2015-01-01

    Premature birth is highly prevalent and associated with neurodevelopmental delays and disorders. Adverse outcomes, particularly in children born before 32 weeks of gestation, have been attributed in large part to white matter injuries, often found in periventricular regions using conventional imaging. To date, tractography studies of white matter pathways in children and adolescents born preterm have evaluated only a limited number of tracts simultaneously. The current study compares diffusion properties along 18 major cerebral white matter pathways in children and adolescents born preterm (n = 27) and full term (n = 19), using diffusion magnetic resonance imaging and tractography. We found that compared to the full term group, the preterm group had significantly decreased FA in segments of the bilateral uncinate fasciculus and anterior segments of the right inferior fronto-occipital fasciculus. Additionally, the preterm group had significantly increased FA in segments of the right and left anterior thalamic radiations, posterior segments of the right inferior fronto-occipital fasciculus, and the right and left inferior longitudinal fasciculus. Increased FA in the preterm group was generally associated with decreased radial diffusivity. These findings indicate that prematurity-related white matter differences in later childhood and adolescence do not affect all tracts in the periventricular zone and can involve both decreased and increased FA. Differences in the patterns of radial diffusivity and axial diffusivity suggest that the tissue properties underlying group FA differences may vary within and across white matter tracts. Distinctive diffusion properties may relate to variations in the timing of injury in the neonatal period, extent of white matter dysmaturity and/or compensatory processes in childhood. PMID:26560745

  15. Failure to Identify the Left Arcuate Fasciculus at Diffusion Tractography Is a Specific Marker of Language Dysfunction in Pediatric Patients with Polymicrogyria

    PubMed Central

    Paldino, Michael J.; Hedges, Kara; Gaab, Nadine; Galaburda, Albert M.; Grant, P. Ellen

    2015-01-01

    Background. Polymicrogyric cortex demonstrates interindividual variation with regard to both extent of dyslamination and functional capacity. Given the relationship between laminar structure and white matter fibers, we sought to define the relationship between polymicrogyria (PMG), intrahemispheric association pathways, and network function. Methods. Each arcuate fasciculus (AF) was categorized as present or absent. Language was characterized by a pediatric neurologist. The presence of dysplastic cortex in the expected anatomic locations of Broca's (BA) and Wernicke's areas (WA) was evaluated by two pediatric neuroradiologists blinded to DTI and language data. Results. 16 PMG patients and 16 age/gender-matched controls were included. All normative controls had an identifiable left AF. 6/7 PMG patients with dysplastic cortex within BA and/or WA had no left AF; PMG patients without involvement of these regions had a lower frequency of absence of the left AF (p < 0.006). All patients without a left AF had some degree of language impairment. PMG patients without a left AF had a significantly greater frequency of language impairment compared to those PMG patients with a left AF (p < 0.003). Conclusion. In patients with PMG (1) the presence of dysplastic cortex within WA and/or BA is associated with absence of the left AF and (2) absence of the left AF is associated with language impairment. PMID:26180373

  16. Downbeat nystagmus associated with damage to the medial longitudinal fasciculus of the pons: a vestibular balance control mechanism via the lower brainstem paramedian tract neurons.

    PubMed

    Nakamagoe, Kiyotaka; Fujizuka, Natsu; Koganezawa, Tadachika; Yamaguchi, Tetsuto; Tamaoka, Akira

    2013-05-15

    The paramedian tract (PMT) neurons, a group of neurons associated with eye movement that project into the cerebellar flocculus, are present in or near the medial longitudinal fasciculus (MLF) in the paramedian region of the lower brainstem. A 66-year-old man with multiple sclerosis in whom downbeat nystagmus appeared along with right MLF syndrome due to a unilateral pontomedullary lesion is described. In light of these findings, a possible schema for the vestibular balance control mechanism circuit of the PMT neurons via the flocculus is presented. Damage to the PMT neurons impaired the elective inhibitory control mechanism of the anterior semicircular canal neural pathway by the flocculus. This resulted in the appearance of anterior semicircular canal-dominant vestibular imbalance and the formation of downbeat nystagmus. From the pathogenesis of this vertical vestibular nystagmus, the action of the PMT neurons in the vestibular eye movement neuronal pathway to maintain vestibular balance was conjectured to be as follows. PMT neurons transmit vestibular information from the anterior semicircular canals to the cerebellum, forming a cerebellum/brainstem feedback loop. Vestibular information from that loop is integrated in the cerebellum, inhibiting only the anterior semicircular canal neuronal pathway via the flocculus and controlling vestibular balance. PMID:23510567

  17. Adding insult to injury: childhood and adolescent risk factors for psychosis predict lower fractional anisotropy in the superior longitudinal fasciculus in healthy adults

    PubMed Central

    DeRosse, Pamela; Ikuta, Toshikazu; Peters, Bart D.; Karlsgodt, Katherine H.; Szeszko, Philip R.; Malhotra, Anil K.

    2014-01-01

    Although epidemiological studies provide strong support for demographic and environmental risk factors in psychotic disorders, few data examine how these risk factors relate to the putative aberrant neurodevelopment associated with illness. The present study examined how the accumulation of risk factors including low IQ, low parental socioeconomic status, history of adolescent cannabis use and childhood trauma, and high levels of subclinical psychotic-like experiences contributed to aberrant neurodevelopmental outcomes in 112 otherwise healthy adults recruited from the community. Participants were studied with diffusion tensor imaging, and voxel-wise statistical analysis of fractional anisotropy (FA) using tract-based spatial statistics was used to examine the relation between cumulative risk (CR) for psychosis and white matter (WM) integrity across the whole brain. Analyses revealed that higher CR was significantly associated with lower FA in a cluster in the left superior longitudinal fasciculus. These results suggest that risk factors previously associated with psychotic disorders are associated with WM integrity even in otherwise healthy adults and may provide insight into how previously identified risk factors contribute to the structural brain abnormalities associated with psychotic illness. Prospective longitudinal studies examining the effect of risk factors on the developmental trajectory of brain WM are warranted. PMID:25277095

  18. Virtual in vivo interactive dissection of white matter fasciculi in the human brain.

    PubMed

    Catani, Marco; Howard, Robert J; Pajevic, Sinisa; Jones, Derek K

    2002-09-01

    This work reports the use of diffusion tensor magnetic resonance tractography to visualize the three-dimensional (3D) structure of the major white matter fasciculi within living human brain. Specifically, we applied this technique to visualize in vivo (i) the superior longitudinal (arcuate) fasciculus, (ii) the inferior longitudinal fasciculus, (iii) the superior fronto-occipital (subcallosal) fasciculus, (iv) the inferior frontooccipital fasciculus, (v) the uncinate fasciculus, (vi) the cingulum, (vii) the anterior commissure, (viii) the corpus callosum, (ix) the internal capsule, and (x) the fornix. These fasciculi were first isolated and were then interactively displayed as a 3D-rendered object. The virtual tract maps obtained in vivo using this approach were faithful to the classical descriptions of white matter anatomy that have previously been documented in postmortem studies. Since we have been able to interactively delineate and visualize white matter fasciculi over their entire length in vivo, in a manner that has only previously been possible by histological means, "virtual in vivo interactive dissection" (VIVID) adds a new dimension to anatomical descriptions of the living human brain. PMID:12482069

  19. White Matter Microstructure in Attention-Deficit/Hyperactivity Disorder Subjects and Their Siblings

    PubMed Central

    Lawrence, Katherine E.; Levitt, Jennifer G.; Loo, Sandra K.; Ly, Ronald; Yee, Victor; O’Neill, Joseph; Alger, Jeffry; Narr, Katherine L.

    2013-01-01

    Objective Previous voxel-based and regions-of-interest (ROI)-based diffusion tensor imaging (DTI) studies have found above-normal mean diffusivity (MD) and below-normal fractional anisotropy (FA) in subjects with attention-deficit/hyperactivity disorder (ADHD). However, findings remain mixed and few studies have examined the contribution of ADHD familial liability to white matter microstructure. Method We used refined DTI tractography methods to examine MD, FA, axial diffusivity (AD) and radial diffusivity (RD) of the anterior thalamic radiation, cingulum, corticospinal tract, inferior fronto-occipital fasciculus, inferior longitudinal fasciculus, forceps major, forceps minor, superior longitudinal fasciculus and uncinate fasciculus in children and adolescents with ADHD (n = 56), unaffected siblings of ADHD probands (n = 31) and healthy controls (n = 17). Results Subjects with ADHD showed significantly higher MD than controls in the anterior thalamic radiation, forceps minor, and superior longitudinal fasciculus. Unaffected siblings of subjects with ADHD displayed similar differences in MD as subjects with ADHD. While none of the tested tracts showed a significant effect of FA, the tracts with elevated MD likewise displayed elevated AD in both subjects with ADHD and unaffected siblings. Differences in RD between subjects with ADHD, unaffected siblings and controls were not as widespread as differences in MD and AD. Conclusion Our findings suggest that disruptions in white matter microstructure occur in several large white matter pathways in association with ADHD and indicate a familial liability for the disorder. Furthermore, MD may reflect these abnormalities more sensitively than FA. PMID:23582873

  20. Language-general and -specific white matter microstructural bases for reading

    PubMed Central

    Zhang, Mingxia; Chen, Chuansheng; Xue, Gui; Lu, Zhong-lin; Mei, Leilei; Xue, Hongli; Wei, Miao; He, Qinghua; Li, Jin; Dong, Qi

    2014-01-01

    In the past decade, several studies have investigated language-general and -specific brain regions for reading. However, very limited research has examined the white matter that connects these cortical regions. By using diffusion tensor imaging (DTI), the current study investigated the common and divergent relationship between white matter integrity indexed by fractional anisotropy (FA) and native language reading abilities in 89 Chinese and 93 English speakers. Conjunction analysis revealed that for both groups, reading ability was associated with the FA of seven white matter fiber bundles in two main anatomical locations in the left hemisphere: the dorsal corona radiate/corpus callosum/superior longitudinal fasciculus which might be for phonological access, and the ventral uncinate fasciculus/external capsule/inferior fronto-occipital fasciculus which might be for semantic processing. Contrast analysis showed that the FA of the left temporal part of superior longitudinal fasciculus contributed more to reading in English than in Chinese, which is consistent with the notion that this tract is involved in grapheme-to-phoneme conversion for alphabetic language reading. These results are the first evidence of language-general and –specific white matter microstructural bases for reading. PMID:24814214

  1. Delayed early developmental trajectories of white matter tracts of functional pathways in preterm-born infants: Longitudinal diffusion tensor imaging data.

    PubMed

    Chang, Linda; Akazawa, Kentaro; Yamakawa, Robyn; Hayama, Sara; Buchthal, Steven; Alicata, Daniel; Andres, Tamara; Castillo, Deborrah; Oishi, Kumiko; Skranes, Jon; Ernst, Thomas; Oishi, Kenichi

    2016-03-01

    Probabilistic maps of white matter pathways related to motor, somatosensory, auditory, visual, and limbic functions, and major white matter tracts (the corpus callosum, the inferior fronto-occipital fasciculus, and the middle cerebellar peduncle) were applied to evaluate the developmental trajectories of these tracts, using longitudinal diffusion tensor imaging (DTI) obtained in term-born and preterm-born healthy infants. Nineteen term-born and 30 preterm-born infants completed MR scans at three time points: Time-point 1, 41.6±2.7 postmenstrual weeks; Time-point 2, 46.0±2.9 postmenstrual weeks; and Time-point 3, 50.8±3.7 postmenstrual weeks. The DTI-derived scalar values (fractional anisotropy, eigenvalues, and radial diffusivity) of the three time points are available in this Data article. PMID:26958632

  2. Delayed early developmental trajectories of white matter tracts of functional pathways in preterm-born infants: Longitudinal diffusion tensor imaging data

    PubMed Central

    Chang, Linda; Akazawa, Kentaro; Yamakawa, Robyn; Hayama, Sara; Buchthal, Steven; Alicata, Daniel; Andres, Tamara; Castillo, Deborrah; Oishi, Kumiko; Skranes, Jon; Ernst, Thomas; Oishi, Kenichi

    2016-01-01

    Probabilistic maps of white matter pathways related to motor, somatosensory, auditory, visual, and limbic functions, and major white matter tracts (the corpus callosum, the inferior fronto-occipital fasciculus, and the middle cerebellar peduncle) were applied to evaluate the developmental trajectories of these tracts, using longitudinal diffusion tensor imaging (DTI) obtained in term-born and preterm-born healthy infants. Nineteen term-born and 30 preterm-born infants completed MR scans at three time points: Time-point 1, 41.6±2.7 postmenstrual weeks; Time-point 2, 46.0±2.9 postmenstrual weeks; and Time-point 3, 50.8±3.7 postmenstrual weeks. The DTI-derived scalar values (fractional anisotropy, eigenvalues, and radial diffusivity) of the three time points are available in this Data article.

  3. White Matter Microstructure and the Variable Adult Outcome of Childhood Attention Deficit Hyperactivity Disorder

    PubMed Central

    Shaw, Philip; Sudre, Gustavo; Wharton, Amy; Weingart, Daniel; Sharp, Wendy; Sarlls, Joelle

    2015-01-01

    Changes in cerebral cortical anatomy have been tied to the clinical course of attention deficit hyperactivity disorder (ADHD). We now ask if alterations in white matter tract microstructure are likewise linked with the adult outcome of childhood ADHD. Seventy-five young adults, 32 with ADHD persisting from childhood and 43 with symptom remission were contrasted against 74 never-affected comparison subjects. Using diffusion tensor imaging, we defined fractional anisotropy, a metric related to white matter microstructure, along with measures of diffusion perpendicular (radial) and parallel (axial) to the axon. Analyses were adjusted for head motion, age and sex, and controlled for multiple comparisons and medication history. Tract-based analyses showed that greater adult inattention, but not hyperactivity–impulsivity, was associated with significantly lower fractional anisotropy in the left uncinate (standardized β=−0.37, t=3.28, p=0.002) and inferior fronto-occipital fasciculi (standardized β=−0.37, t=3.29, p=0.002). The ADHD group with symptoms persisting into adulthood had significantly lower fractional anisotropy than the never-affected controls in these tracts, differences associated with medium to large effect sizes. By contrast, the ADHD group that remitted by adulthood did not differ significantly from controls. The anomalies were found in tracts that connect components of neural systems pertinent to ADHD, such as attention control (inferior fronto-occipital fasciculus) and emotion regulation and the processing of reward (the uncinate fasciculus). Change in radial rather than axial diffusivity was the primary driver of this effect, suggesting pathophysiological processes including altered myelination as future targets for pharmacological and behavioral interventions. PMID:25241803

  4. White matter microstructure and the variable adult outcome of childhood attention deficit hyperactivity disorder.

    PubMed

    Shaw, Philip; Sudre, Gustavo; Wharton, Amy; Weingart, Daniel; Sharp, Wendy; Sarlls, Joelle

    2015-02-01

    Changes in cerebral cortical anatomy have been tied to the clinical course of attention deficit hyperactivity disorder (ADHD). We now ask if alterations in white matter tract microstructure are likewise linked with the adult outcome of childhood ADHD. Seventy-five young adults, 32 with ADHD persisting from childhood and 43 with symptom remission were contrasted against 74 never-affected comparison subjects. Using diffusion tensor imaging, we defined fractional anisotropy, a metric related to white matter microstructure, along with measures of diffusion perpendicular (radial) and parallel (axial) to the axon. Analyses were adjusted for head motion, age and sex, and controlled for multiple comparisons and medication history. Tract-based analyses showed that greater adult inattention, but not hyperactivity-impulsivity, was associated with significantly lower fractional anisotropy in the left uncinate (standardized β=-0.37, t=3.28, p=0.002) and inferior fronto-occipital fasciculi (standardized β=-0.37, t=3.29, p=0.002). The ADHD group with symptoms persisting into adulthood had significantly lower fractional anisotropy than the never-affected controls in these tracts, differences associated with medium to large effect sizes. By contrast, the ADHD group that remitted by adulthood did not differ significantly from controls. The anomalies were found in tracts that connect components of neural systems pertinent to ADHD, such as attention control (inferior fronto-occipital fasciculus) and emotion regulation and the processing of reward (the uncinate fasciculus). Change in radial rather than axial diffusivity was the primary driver of this effect, suggesting pathophysiological processes including altered myelination as future targets for pharmacological and behavioral interventions. PMID:25241803

  5. Delineation of Early and Later Adult Onset Depression by Diffusion Tensor Imaging

    PubMed Central

    Yu, Hongjun; Nie, Binbin; Li, Na; Luo, Chunrong; Li, Haijun; Liu, Fang; Bai, Yan; Shan, Baoci; Xu, Lin; Xu, Xiufeng

    2014-01-01

    Background Due to a lack of evidence, there is no consistent age of onset to define early onset (EO) versus later onset (LO) major depressive disorder (MDD). Fractional anisotropy (FA), derived from diffusion tensor imaging (DTI), has been widely used to study neuropsychiatric disorders by providing information about the brain circuitry, abnormalities of which might facilitate the delineation of EO versus LO MDD. Method In this study, 61 pairs of untreated, non-elderly, first-episode MDD patients and healthy controls (HCs) aged 18–45 years old received DTI scans. The voxel-based analysis method (VBM), classification analysis, using the Statistical Package for the Social Sciences (SPSS), and regression analyses were used to determine abnormal FA clusters and their correlations with age of onset and clinical symptoms. Results Classification analysis suggested in the best model that there were two subgroups of MDD patients, delineated by an age of onset of 30 years old, by which MDD patients could be divided into EO (18–29 years old) and LO (30–45 years old) groups. LO MDD was characterized by decreased FA, especially in the white matter (WM) of the fronto-occipital fasciculus and posterior limb of internal capsule, with a negative correlation with the severity of depressive symptoms; in marked contrast, EO MDD showed increased FA, especially in the WM of the corpus callosum, corticospinal midbrain and inferior fronto-occipital fasciculus, while FA of the WM near the midbrain had a positive correlation with the severity of depressive symptoms. Conclusion Specific abnormalities of the brain circuitry in EO vs. LO MDD were delineated by an age of onset of 30 years old, as demonstrated by distinct abnormal FA clusters with opposite correlations with clinical symptoms. This DTI study supported the evidence of an exact age for the delineation of MDD, which could have broad multidisciplinary importance. Trial Registration ClinicalTrials.gov NCT00703742 PMID:25393297

  6. Lithium and GSK3-β Promoter Gene Variants Influence White Matter Microstructure in Bipolar Disorder

    PubMed Central

    Benedetti, Francesco; Bollettini, Irene; Barberi, Ignazio; Radaelli, Daniele; Poletti, Sara; Locatelli, Clara; Pirovano, Adele; Lorenzi, Cristina; Falini, Andrea; Colombo, Cristina; Smeraldi, Enrico

    2013-01-01

    Lithium is the mainstay for the treatment of bipolar disorder (BD) and inhibits glycogen synthase kinase 3-β (GSK3-β). The less active GSK3-β promoter gene variants have been associated with less detrimental clinical features of BD. GSK3-β gene variants and lithium can influence brain gray matter structure in psychiatric conditions. Diffusion tensor imaging (DTI) measures of white matter (WM) integrity showed widespred disruption of WM structure in BD. In a sample of 70 patients affected by a major depressive episode in course of BD, we investigated the effect of ongoing long-term lithium treatment and GSK3-β promoter rs334558 polymorphism on WM microstructure, using DTI and tract-based spatial statistics with threshold-free cluster enhancement. We report that the less active GSK3-β rs334558*C gene-promoter variants, and the long-term administration of the GSK3-β inhibitor lithium, were associated with increases of DTI measures of axial diffusivity (AD) in several WM fiber tracts, including corpus callosum, forceps major, anterior and posterior cingulum bundle (bilaterally including its hippocampal part), left superior and inferior longitudinal fasciculus, left inferior fronto-occipital fasciculus, left posterior thalamic radiation, bilateral superior and posterior corona radiata, and bilateral corticospinal tract. AD reflects the integrity of axons and myelin sheaths. We suggest that GSK3-β inhibition and lithium could counteract the detrimental influences of BD on WM structure, with specific benefits resulting from effects on specific WM tracts contributing to the functional integrity of the brain and involving interhemispheric, limbic, and large frontal, parietal, and fronto-occipital connections. PMID:22990942

  7. Localization of Brain White Matter Hyperintensities and Urinary Incontinence in Community-Dwelling Older Adults

    PubMed Central

    Moscufo, Nicola; Guttmann, Charles R.; Zeevi, Neer; Wakefield, Dorothy; Schmidt, Julia; DuBeau, Catherine E.; Wolfson, Leslie

    2009-01-01

    Background Because white matter hyperintensities (WMHs) on magnetic resonance imaging (MRI) may be linked to geriatric syndromes involving mobility, cognition, and affect, we postulated that involvement of areas critical to bladder control could influence urinary incontinence (UI). Methods One hundred community-dwelling individuals (75–89 years) were recruited into three groups stratified by age and gender reflecting normal and mildly and moderately impaired mobility. Baseline incontinence status and related symptoms were evaluated in 97 individuals using validated instruments (3IQ, Urinary Incontinence Severity Index, Urogenital Distress Inventory, Incontinence Impact Questionnaire). Regional WMH was measured using an MRI brain imaging segmentation pipeline and WM tract–based parcellation atlas. Results Sixty-two (64%) of the participants were incontinent, mostly with urgency (37; 60%) and moderate–severe symptoms (36; 58%). Incontinent individuals were more likely to be women with worse scores for depression and mobility. WMH located in right inferior frontal regions predicted UI severity, with no significant relationship with incontinence, incontinence type, bother, or functional impact. As regards WM tracts, WMH within regions normally occupied by the anterior corona radiata predicted severity and degree of bother, cingulate gyrus predicted incontinence and severity, whereas cingulate (hippocampal portion) and superior fronto-occipital fasciculus predicted severity. Conclusions Presence of WMH in right inferior frontal regions and selected WM tracts predicts incontinence, incontinence severity, and degree of bother. Our observations support the findings of recent functional MRI studies indicating a critical role for the cingulum in bladder control, while also suggesting potential involvement of other nearby WM tracts such as anterior corona radiata and superior fronto-occipital fasciculus. PMID:19386575

  8. Investigating the ventral-lexical, dorsal-sublexical model of basic reading processes using diffusion tensor imaging.

    PubMed

    Cummine, Jacqueline; Dai, Wenjun; Borowsky, Ron; Gould, Layla; Rollans, Claire; Boliek, Carol

    2015-01-01

    Recent results from diffusion tensor imaging (DTI) studies provide evidence of a ventral-lexical stream and a dorsal-sublexical stream associated with reading processing. We investigated the relationship between behavioural reading speed for stimuli thought to rely on either the ventral-lexical, dorsal-sublexical, or both streams and white matter via fractional anisotropy (FA) and mean diffusivity (MD) using DTI tractography. Participants (N = 32) overtly named exception words (e.g., 'one', ventral-lexical), regular words (e.g., 'won', both streams), nonwords ('wum', dorsal-sublexical) and pseudohomophones ('wun', dorsal-sublexical) in a behavioural lab. Each participant then underwent a brain scan that included a 30-directional DTI sequence. Tractography was used to extract FA and MD values from four tracts of interest: inferior longitudinal fasciculus, uncinate fasciculus, arcuate fasciculus, and inferior fronto-occipital fasciculus. Median reaction times (RTs) for reading exception words and regular words both showed a significant correlation with the FA of the uncinate fasciculus thought to underlie the ventral processing stream, such that response time decreased as FA increased. In addition, RT for exception and regular words showed a relationship with MD of the uncinate fasciculus, such that response time increased as MD increased. Multiple regression analyses revealed that exception word RT accounted for unique variability in FA of the uncinate over and above regular words. There were no robust relationships found between pseudohomophones, or nonwords, and tracts thought to underlie the dorsal processing stream. These results support the notion that word recognition, in general, and exception word reading in particular, rely on ventral-lexical brain regions. PMID:24189777

  9. Asymmetry of White Matter Pathways in Developing Human Brains.

    PubMed

    Song, Jae W; Mitchell, Paul D; Kolasinski, James; Ellen Grant, P; Galaburda, Albert M; Takahashi, Emi

    2015-09-01

    Little is known about the emergence of structural asymmetry of white matter tracts during early brain development. We examined whether and when asymmetry in diffusion parameters of limbic and association white matter pathways emerged in humans in 23 brains ranging from 15 gestational weeks (GW) up to 3 years of age (11 ex vivo and 12 in vivo cases) using high-angular resolution diffusion imaging tractography. Age-related development of laterality was not observed in a limbic connectional pathway (cingulum bundle or fornix). Among the studied cortico-cortical association pathways (inferior longitudinal fasciculus [ILF], inferior fronto-occipital fasciculus, and arcuate fasciculus), only the ILF showed development of age-related laterality emerging as early as the second trimester. Comparisons of ages older and younger than 40 GW revealed a leftward asymmetry in the cingulum bundle volume and a rightward asymmetry in apparent diffusion coefficient and leftward asymmetry in fractional anisotropy in the ILF in ages older than 40 GW. These results suggest that morphometric asymmetry in cortical areas precedes the emergence of white matter pathway asymmetry. Future correlative studies will investigate whether such asymmetry is anatomically/genetically driven or associated with functional stimulation. PMID:24812082

  10. In Vivo Tractography of Fetal Association Fibers

    PubMed Central

    Mitter, Christian; Prayer, Daniela; Brugger, Peter C.; Weber, Michael; Kasprian, Gregor

    2015-01-01

    Association fibers connect different cortical areas within the same hemisphere and constitute an essential anatomical substrate for a diverse range of higher cognitive functions. So far a comprehensive description of the prenatal in vivo morphology of these functionally important pathways is lacking. In the present study, diffusion tensor imaging (DTI) and tractography were used to visualize major association fiber tracts and the fornix in utero in preselected non-motion degraded DTI datasets of 24 living unsedated fetuses between 20 and 34 gestational weeks (GW). The uncinate fasciculus and inferior fronto-occipital fasciculus were depicted as early as 20 GW, while in vivo 3D visualization of the inferior longitudinal fasciculus, cingulum and fornix was successful in older fetuses during the third trimester. Provided optimal scanning conditions, in utero DTI and tractography have the potential to provide a more accurate anatomical definition of developing neuronal networks in the human fetal brain. Knowledge about the normal prenatal 3D association tract morphology may serve as reference for their assessment in common developmental diseases. PMID:25742520

  11. Gray- and white-matter anatomy of absolute pitch possessors.

    PubMed

    Dohn, Anders; Garza-Villarreal, Eduardo A; Chakravarty, M Mallar; Hansen, Mads; Lerch, Jason P; Vuust, Peter

    2015-05-01

    Absolute pitch (AP), the ability to identify a musical pitch without a reference, has been examined behaviorally in numerous studies for more than a century, yet only a few studies have examined the neuroanatomical correlates of AP. Here, we used MRI and diffusion tensor imaging to investigate structural differences in brains of musicians with and without AP, by means of whole-brain vertex-wise cortical thickness (CT) analysis and tract-based spatial statistics (TBSS) analysis. APs displayed increased CT in a number of areas including the bilateral superior temporal gyrus (STG), the left inferior frontal gyrus, and the right supramarginal gyrus. Furthermore, we found higher fractional anisotropy in APs within the path of the inferior fronto-occipital fasciculus, the uncinate fasciculus, and the inferior longitudinal fasciculus. The findings in gray matter support previous studies indicating an increased left lateralized posterior STG in APs, yet they differ from previous findings of thinner cortex for a number of areas in APs. Finally, we found a relation between the white-matter results and the CT in the right parahippocampal gyrus. In this study, we present novel findings in AP research that may have implications for the understanding of the neuroanatomical underpinnings of AP ability. PMID:24304583

  12. White matter integrity is associated with CSF markers of AD in normal adults

    PubMed Central

    Gold, Brian T.; Zhu, Zude; Brown, Christopher A.; Andersen, Anders H.; LaDu, Mary Jo; Tai, Leon; Jicha, Greg A.; Kryscio, Richard J.; Estus, Steven; Nelson, Peter T.; Scheff, Steve W.; Abner, Erin; Schmitt, Fred A.; Van Eldik, Linda J.; Smith, Charles D.

    2014-01-01

    We explored whether white matter (WM) integrity in cognitively normal (CN) older adults is associated with cerebrospinal fluid (CSF) markers of Alzheimer’s disease (AD) pathology. Twenty CN older adults underwent lumbar puncture and magnetic resonance imaging within a few days of each other. Analysis of diffusion tensor imaging data involved a priori region of interest (ROI) and voxelwise approaches. The ROI results revealed a positive correlation between CSF measures of amyloid-beta (A?42 and A?42/p-Tau181) and WM integrity in the fornix, a relationship which persisted after controlling for hippocampal volume and fornix volume. Lower WM integrity in the same portion of the fornix was also associated with reduced performance on the Digit Symbol test. Subsequent exploratory voxelwise analyses indicated a positive correlation between CSF A?42/p-Tau181 and WM integrity in bilateral portions of the fornix, superior longitudinal fasciculus, inferior fronto-occipital fasciculus, and in the corpus callosum and left inferior longitudinal fasciculus. Our results link lower WM microstructural integrity in CN older adults with CSF biomarkers of AD and suggest that this association in the fornix may be independent of volumetric measures. PMID:24866404

  13. Microstructure and Cerebral Blood Flow within White Matter of the Human Brain: A TBSS Analysis

    PubMed Central

    Giezendanner, Stéphanie; Fisler, Melanie Sarah; Soravia, Leila Maria; Andreotti, Jennifer; Walther, Sebastian; Wiest, Roland; Dierks, Thomas; Federspiel, Andrea

    2016-01-01

    Background White matter (WM) fibers connect different brain regions and are critical for proper brain function. However, little is known about the cerebral blood flow in WM and its relation to WM microstructure. Recent improvements in measuring cerebral blood flow (CBF) by means of arterial spin labeling (ASL) suggest that the signal in white matter may be detected. Its implications for physiology needs to be extensively explored. For this purpose, CBF and its relation to anisotropic diffusion was analyzed across subjects on a voxel-wise basis with tract-based spatial statistics (TBSS) and also across white matter tracts within subjects. Methods Diffusion tensor imaging and ASL were acquired in 43 healthy subjects (mean age = 26.3 years). Results CBF in WM was observed to correlate positively with fractional anisotropy across subjects in parts of the splenium of corpus callosum, the right posterior thalamic radiation (including the optic radiation), the forceps major, the right inferior fronto-occipital fasciculus, the right inferior longitudinal fasciculus and the right superior longitudinal fasciculus. Furthermore, radial diffusivity correlated negatively with CBF across subjects in similar regions. Moreover, CBF and FA correlated positively across white matter tracts within subjects. Conclusion The currently observed findings on a macroscopic level might reflect the metabolic demand of white matter on a microscopic level involving myelination processes or axonal function. However, the exact underlying physiological mechanism of this relationship needs further evaluation. PMID:26942763

  14. Brodmann’s Area Template Based Region of Interest Setting and Probabilistic Pathway Map Generation in Diffusion Tensor Tractography: Application to the Arcuate Fasciculus Fiber Tract in the Human Brain

    PubMed Central

    Lee, Dong-Hoon; Lee, Do-Wan; Han, Bong-Soo

    2016-01-01

    The purpose of this study is to acquire accurate diffusion tensor tractography (DTT) results for arcuate fasciculus (AF) fiber tract using Brodmann’s area (BA) template for region of interest (ROI) setting. Thirteen healthy subjects were participated in this study. Fractional anisotropy (FA) map of each subject was calculated using diffusion tensor data, and T1w template was co-registered to FA map. The BA template was also co-registered using the transformation matrix. The ROIs were drawn in the co-registered BA template, and AF fiber tract was extracted. To generate the probabilistic pathway map, a binary mask image was generated based on the fiber tract image and co-registered to T1w template image. We also measured relative location of the AF fiber tract. The location of the probabilistic pathway map of each subject’s AF fiber tract was well defined in the brain. By using this probabilistic map, the mediolateral position ratio of AF was measured 18%, and the anteroposterior position ratio of AF was measured 35%, respectively. This study demonstrated that the AF fiber tract can be extracted using BA template for ROI setting and probabilistic pathway of fiber tract. Our results and analytical approaches can helpful for accurate fiber tracking and application of perspective clinical researches. PMID:26834574

  15. Combined DTI Tractography and Functional MRI Study of the Language Connectome in Healthy Volunteers: Extensive Mapping of White Matter Fascicles and Cortical Activations.

    PubMed

    Vassal, François; Schneider, Fabien; Boutet, Claire; Jean, Betty; Sontheimer, Anna; Lemaire, Jean-Jacques

    2016-01-01

    Despite a better understanding of brain language organization into large-scale cortical networks, the underlying white matter (WM) connectivity is still not mastered. Here we combined diffusion tensor imaging (DTI) fiber tracking (FT) and language functional magnetic resonance imaging (fMRI) in twenty healthy subjects to gain new insights into the macroscopic structural connectivity of language. Eight putative WM fascicles for language were probed using a deterministic DTI-FT technique: the arcuate fascicle (AF), superior longitudinal fascicle (SLF), uncinate fascicle (UF), temporo-occipital fascicle, inferior fronto-occipital fascicle (IFOF), middle longitudinal fascicle (MdLF), frontal aslant fascicle and operculopremotor fascicle. Specific measurements (i.e. volume, length, fractional anisotropy) and precise cortical terminations were derived for each WM fascicle within both hemispheres. Connections between these WM fascicles and fMRI activations were studied to determine which WM fascicles are related to language. WM fascicle volumes showed asymmetries: leftward for the AF, temporoparietal segment of SLF and UF, and rightward for the frontoparietal segment of the SLF. The lateralization of the AF, IFOF and MdLF extended to differences in patterns of anatomical connections, which may relate to specific hemispheric abilities. The leftward asymmetry of the AF was correlated to the leftward asymmetry of fMRI activations, suggesting that the lateralization of the AF is a structural substrate of hemispheric language dominance. We found consistent connections between fMRI activations and terminations of the eight WM fascicles, providing a detailed description of the language connectome. WM fascicle terminations were also observed beyond fMRI-confirmed language areas and reached numerous cortical areas involved in different functional brain networks. These findings suggest that the reported WM fascicles are not exclusively involved in language and might be related to other cognitive functions such as visual recognition, spatial attention, executive functions, memory, and processing of emotional and behavioral aspects. PMID:27029050

  16. The ins and outs of meaning: Behavioral and neuroanatomical dissociation of semantically-driven word retrieval and multimodal semantic recognition in aphasia.

    PubMed

    Mirman, Daniel; Zhang, Yongsheng; Wang, Ze; Coslett, H Branch; Schwartz, Myrna F

    2015-09-01

    Theories about the architecture of language processing differ with regard to whether verbal and nonverbal comprehension share a functional and neural substrate and how meaning extraction in comprehension relates to the ability to use meaning to drive verbal production. We (re-)evaluate data from 17 cognitive-linguistic performance measures of 99 participants with chronic aphasia using factor analysis to establish functional components and support vector regression-based lesion-symptom mapping to determine the neural correlates of deficits on these functional components. The results are highly consistent with our previous findings: production of semantic errors is behaviorally and neuroanatomically distinct from verbal and nonverbal comprehension. Semantic errors were most strongly associated with left ATL damage whereas deficits on tests of verbal and non-verbal semantic recognition were most strongly associated with damage to deep white matter underlying the frontal lobe at the confluence of multiple tracts, including the inferior fronto-occipital fasciculus, the uncinate fasciculus, and the anterior thalamic radiations. These results suggest that traditional views based on grey matter hub(s) for semantic processing are incomplete and that the role of white matter in semantic cognition has been underappreciated. PMID:25681739

  17. Evidence From Structural and Diffusion Tensor Imaging for Frontotemporal Deficits in Psychometric Schizotypy

    PubMed Central

    DeRosse, Pamela; Nitzburg, George C.; Ikuta, Toshikazu; Peters, Bart D.; Malhotra, Anil K.; Szeszko, Philip R.

    2015-01-01

    Background: Previous studies of nonclinical samples exhibiting schizotypal traits have provided support for the existence of a continuous distribution of psychotic symptoms in the general population. Few studies, however, have examined the neural correlates of psychometric schizotypy using structural and diffusion tensor imaging (DTI). Methods: Healthy volunteers between the ages of 18 and 68 were recruited from the community and assessed using the Schizotypal Personality Questionnaire and received structural and DTI exams. Participants with high (N = 67) and low (N = 71) psychometric schizotypy were compared on gray and white matter volume, and cortical thickness in frontal and temporal lobe regions and on fractional anisotropy (FA) within 5 association tracts traversing the frontal and temporal lobes. Results: Higher levels of schizotypy were associated with lower overall volumes of gray matter in both the frontal and temporal lobes and lower gray matter thickness in the temporal lobe. Regionally specific effects were evident in both white matter and gray matter volume of the rostral middle frontal cortex and gray matter volume in the pars orbitalis. Moreover, relative to individuals who scored low, those who scored high in schizotypy had lower FA in the inferior fronto-occipital fasciculus as well as greater asymmetry (right > left) in the uncinate fasciculus. Conclusions: These findings are broadly consistent with recent data on the neurobiological correlates of psychometric schizotypy as well as findings in schizotypal personality disorder and schizophrenia and suggest that frontotemporal lobe dysfunction may represent a core component of the psychosis phenotype. PMID:25392520

  18. White matter microstructure in ultra-high risk and first episode schizophrenia: A prospective study.

    PubMed

    Rigucci, Silvia; Santi, Giulia; Corigliano, Valentina; Imola, Annamaria; Rossi-Espagnet, Camilla; Mancinelli, Iginia; De Pisa, Eleonora; Manfredi, Giovanni; Bozzao, Alessandro; Carducci, Filippo; Girardi, Paolo; Comparelli, Anna

    2016-01-30

    There is increasing evidence of white matter (WM) pathology in schizophrenia, but its role at the very early stage of the disorder remains unclear. In an exploration of WM microstructure in ultra-high risk (UHR) subjects and first episode schizophrenia (FES), 34 FES, 27 UHR and 26 healthy control (HC) subjects underwent a magnetic resonance imaging (MRI) tract based spatial statistics (TBSS) investigation. Whole brain fractional anisotropy (FA), mean diffusivity (MD), radial (RD) and axial diffusivity (AD) values were extracted. UHR subjects who later developed psychosis showed lower FA compared with HC in the corpus callosum (CC), the left superior and inferior longitudinal fasciculus, the left inferior fronto-occipital fasciculs (IFO), and the forceps; RD was significantly higher in the CC, the forceps, the anterior thalamic radiation bilaterally, and the cingulum bundle. FES, compared to HC, showed a significant FA reduction of the CC, the superior and inferior longitudinal fasciculi bilaterally, the IFO bilaterally, the corona radiate bilaterally, and the forceps; while RD was found to be significantly increased in the left superior longitudinal fasciculus. UHR who later developed psychosis had WM abnormalities affecting brain pathways that are crucial for intra- and inter-hemispheric connections. PMID:26651180

  19. Early cerebral volume reductions and their associations with reduced lupus disease activity in patients with newly-diagnosed systemic lupus erythematosus.

    PubMed

    Mak, Anselm; Ho, Roger Chun-Man; Tng, Han-Ying; Koh, Hui Li; Chong, Joanna Su Xian; Zhou, Juan

    2016-01-01

    We examined if cerebral volume reduction occurs very early during the course of systemic lupus erythematosus (SLE), and observed prospectively whether gray (GMV) and white matter volumes (WMV) of the brain would improve with lowered SLE disease activity. T1-weighted MRI brain images were obtained from 14 healthy controls (HC) and 14 newly-diagnosed SLE patients within 5 months of diagnosis (S1) and after achieving low disease activity (S2). Whole brain voxel-based morphometry was used to detect differences in the GMV and WMV between SLE patients and HC and those between SLE patients at S1 and S2. SLE patients were found to have lower GMV than HC in the middle cingulate cortex, middle frontal gyrus and right supplementary motor area, and lower WMV in the superior longitudinal fasciculus, cingulum cingulate gyrus and inferior fronto-occipital fasciculus at both S1 and S2. Whole-brain voxel-wise analysis revealed increased GMV chiefly in the prefrontal regions at S2 compared to S1 in SLE patients. The GMV increase in the left superior frontal gyrus was significantly associated with lowered SLE disease activity. In conclusion, GMV and WMV reduced very early in SLE patients. Reduction of SLE disease activity was accompanied by region-specific GMV improvement in the prefrontal regions. PMID:26928214

  20. Early cerebral volume reductions and their associations with reduced lupus disease activity in patients with newly-diagnosed systemic lupus erythematosus

    PubMed Central

    Mak, Anselm; Ho, Roger Chun-Man; Tng, Han-Ying; Koh, Hui Li; Chong, Joanna Su Xian; Zhou, Juan

    2016-01-01

    We examined if cerebral volume reduction occurs very early during the course of systemic lupus erythematosus (SLE), and observed prospectively whether gray (GMV) and white matter volumes (WMV) of the brain would improve with lowered SLE disease activity. T1-weighted MRI brain images were obtained from 14 healthy controls (HC) and 14 newly-diagnosed SLE patients within 5 months of diagnosis (S1) and after achieving low disease activity (S2). Whole brain voxel-based morphometry was used to detect differences in the GMV and WMV between SLE patients and HC and those between SLE patients at S1 and S2. SLE patients were found to have lower GMV than HC in the middle cingulate cortex, middle frontal gyrus and right supplementary motor area, and lower WMV in the superior longitudinal fasciculus, cingulum cingulate gyrus and inferior fronto-occipital fasciculus at both S1 and S2. Whole-brain voxel-wise analysis revealed increased GMV chiefly in the prefrontal regions at S2 compared to S1 in SLE patients. The GMV increase in the left superior frontal gyrus was significantly associated with lowered SLE disease activity. In conclusion, GMV and WMV reduced very early in SLE patients. Reduction of SLE disease activity was accompanied by region-specific GMV improvement in the prefrontal regions. PMID:26928214

  1. Emerging Structure–Function Relations in the Developing Face Processing System

    PubMed Central

    Suzanne Scherf, K.; Thomas, Cibu; Doyle, Jaime; Behrmann, Marlene

    2014-01-01

    To evaluate emerging structure–function relations in a neural circuit that mediates complex behavior, we investigated age-related differences among cortical regions that support face recognition behavior and the fiber tracts through which they transmit and receive signals using functional neuroimaging and diffusion tensor imaging. In a large sample of human participants (aged 6–23 years), we derived the microstructural and volumetric properties of the inferior longitudinal fasciculus (ILF), the inferior fronto-occipital fasciculus, and control tracts, using independently defined anatomical markers. We also determined the functional characteristics of core face- and place-selective regions that are distributed along the trajectory of the pathways of interest. We observed disproportionately large age-related differences in the volume, fractional anisotropy, and mean and radial, but not axial, diffusivities of the ILF. Critically, these differences in the structural properties of the ILF were tightly and specifically linked with an age-related increase in the size of a key face-selective functional region, the fusiform face area. This dynamic association between emerging structural and functional architecture in the developing brain may provide important clues about the mechanisms by which neural circuits become organized and optimized in the human cortex. PMID:23765156

  2. Altered white matter microstructure is associated with social cognition and psychotic symptoms in 22q11.2 microdeletion syndrome

    PubMed Central

    Jalbrzikowski, Maria; Villalon-Reina, Julio E.; Karlsgodt, Katherine H.; Senturk, Damla; Chow, Carolyn; Thompson, Paul M.; Bearden, Carrie E.

    2014-01-01

    22q11.2 Microdeletion Syndrome (22q11DS) is a highly penetrant genetic mutation associated with a significantly increased risk for psychosis. Aberrant neurodevelopment may lead to inappropriate neural circuit formation and cerebral dysconnectivity in 22q11DS, which may contribute to symptom development. Here we examined: (1) differences between 22q11DS participants and typically developing controls in diffusion tensor imaging (DTI) measures within white matter tracts; (2) whether there is an altered age-related trajectory of white matter pathways in 22q11DS; and (3) relationships between DTI measures, social cognition task performance, and positive symptoms of psychosis in 22q11DS and typically developing controls. Sixty-four direction diffusion weighted imaging data were acquired on 65 participants (36 22q11DS, 29 controls). We examined differences between 22q11DS vs. controls in measures of fractional anisotropy (FA), axial diffusivity (AD), and radial diffusivity (RD), using both a voxel-based and region of interest approach. Social cognition domains assessed were: Theory of Mind and emotion recognition. Positive symptoms were assessed using the Structured Interview for Prodromal Syndromes. Compared to typically developing controls, 22q11DS participants showed significantly lower AD and RD in multiple white matter tracts, with effects of greatest magnitude for AD in the superior longitudinal fasciculus. Additionally, 22q11DS participants failed to show typical age-associated changes in FA and RD in the left inferior longitudinal fasciculus. Higher AD in the left inferior fronto-occipital fasciculus (IFO) and left uncinate fasciculus was associated with better social cognition in 22q11DS and controls. In contrast, greater severity of positive symptoms was associated with lower AD in bilateral regions of the IFO in 22q11DS. White matter microstructure in tracts relevant to social cognition is disrupted in 22q11DS, and may contribute to psychosis risk. PMID:25426042

  3. White-Matter Development is Different in Bilingual and Monolingual Children: A Longitudinal DTI Study

    PubMed Central

    Mohades, Seyede Ghazal; Van Schuerbeek, Peter; Rosseel, Yves; Van De Craen, Piet; Luypaert, Robert; Baeken, Chris

    2015-01-01

    Although numerous people grow up speaking more than one language, the impact of bilingualism on brain developing neuroanatomy is still poorly understood. This study aimed to determine whether the changes in the mean fractional-anisotropy (MFA) of language pathways are different between bilingual and monolingual children. Simultaneous-bilinguals, sequential-bilinguals and monolingual, male and female 10–13 years old children participated in this longitudinal study over a period of two years. We used diffusion tensor tractography to obtain mean fractional-anisotropy values of four language related pathways and one control bundle: 1-left-inferior-occipitofrontal fasciculus/lIFOF, 2-left-arcuate fasciculus/lAF/lSLF, 3-bundle arising from the anterior part of corpus-callosum and projecting to orbital lobe/AC-OL, 4-fibres emerging from anterior-midbody of corpus-callosum (CC) to motor cortices/AMB-PMC, 5- right-inferior-occipitofrontal fasciculus rIFOF as the control pathway unrelated to language. These values and their rate of change were compared between 3 groups. FA-values did not change significantly over two years for lAF/lSLF and AC-OL. Sequential-bilinguals had the highest degree of change in the MFA value of lIFOF, and AMB-PMC did not present significant group differences. The comparison of MFA of lIFOF yielded a significantly higher FA-value in simultaneous bilinguals compared to monolinguals. These findings acknowledge the existing difference of the development of the semantic processing specific pathway between children with different semantic processing procedure. These also support the hypothesis that age of second language acquisition affects the maturation and myelination of some language specific white-matter pathways. PMID:25706865

  4. Neuroimaging changes in the brain in Contact vs. Non-contact sport athletes using Diffusion Tensor Imaging

    PubMed Central

    Lao, Yi; Apuzzo, Michael L.J.; Romano, Russ; Liu, Charles; Tsao, Sinchai; Hwang, Darryl; Wilkins, Bryce; Lepore, Natasha; Law, Meng

    2014-01-01

    Objective Traumatic brain injury in contact sports has significant impact on short term neurological and neurosurgical function as well as longer term cognitive disability. In this study, we aim to demonstrate that contact sport participants exhibit differences in Diffusion Tensor Imaging (DTI) caused by repeated physical impact on the brain. We also aim to determine that impact incurred by the contact sports athletes during the season may result in differences between the pre- and post-season DTI scans. Methods DTI data was collected from 10 contact (mean age 20.4 +- 1.36) and 13 age-matched non-contact (mean age 19.5 +- 1.03) sport male athletes, on a 3T MRI scanner. A single shot echo-planar imaging sequence with b-value of 1000s/mm2 and 25 gradient directions was used. Eight of the athletes were again scanned post-season. The b0 non-diffusion weighted image was averaged 5 times. Voxel-wise 2-sample t-tests were run for all group comparisons, and in each case, the positive false discovery rate (pFDR) was computed to assess the whole map, multiple comparison corrected significance. Results There were significant differences in the FA values in the inferior fronto-occipital fasciculus, parts of the superior and posterior coronal radiate and the splenium of the corpus callosum (CC) as well as smaller clusters in the genu and parts of the body of the CC. In addition, the external capsule also shows some difference between the contact and non-contact athlete brains. Additionally, the pre-season and postseason show differences in these regions, however, the post-season p-values show significance in more areas of the CC. Conclusions There are significant DTI changes in the corpus callosum, the external capsule, the inferior fronto-occipital fasciculus as well as regions such as the superior/posterior corona radiata when comparing the pre-season contact versus the non-contact controls and also comparing the post-season contact athletes with the controls. There are also difference in the DTI between the post- vs. pre-season scans. PMID:24120614

  5. White Matter Integrity in Physically Fit Older Adults

    PubMed Central

    Tseng, B.Y.; Gundapuneedi, T.; Khan, M.A.; Diaz-Arrastia, R.; Levine, B.D.; Lu, H.; Huang, H.; Zhang, R.

    2013-01-01

    Background White matter (WM) integrity declines with normal aging. Physical activity may attenuate age-related WM integrity changes and improve cognitive function. This study examined brain WM integrity in Masters athletes who have engaged in life-long aerobic exercise training. We tested the hypothesis that life-long aerobic training is associated with improved brain WM integrity in older adults. Methods Ten Masters athletes (3 females, age=72.2±5.3yrs, endurance training>15yrs) and 10 sedentary older adults similar in age and educational level (2 females, age=74.5±4.3yrs) participated. MRI fluid-attenuated-inversion-recovery (FLAIR) images were acquired to assess white matter hyper intensities (WMH) volume. Diffusion tensor imaging (DTI) was performed to evaluate the WM microstructural integrity with a DTI-derived metric, fractional anisotropy (FA) and mean diffusivity (MD). Results After normalization to whole-brain volume, Masters athletes showed an 83% reduction in deep WMH volume relative to their sedentary counterparts (0.05 ± 0.05% vs. 0.29 ± 0.29%, p<0.05). In addition, we found an inverse relationship between aerobic fitness (VO2max) and deep WMH volume (r=?0.78, p<0.001). Using TBSS, Masters athletes showed higher FA values in the right superior corona radiata (SCR), both sides of superior longitudinal fasciculus (SLF), right inferior fronto-occipital fasciculus (IFO), and left inferior longitudinal fasciculus (ILF). In addition, Masters athletes also showed lower MD values in the left posterior thalamic radiation (PTR) and left cingulum hippocampus. Conclusions These findings suggest that life-long exercise is associated with reduced WMH and may preserve WM fiber microstructural integrity related to motor control and coordination in older adults. PMID:23769914

  6. Multi-modal MRI of mild traumatic brain injury

    PubMed Central

    Narayana, Ponnada A.; Yu, Xintian; Hasan, Khader M.; Wilde, Elisabeth A.; Levin, Harvey S.; Hunter, Jill V.; Miller, Emmy R.; Patel, Vipul Kumar S.; Robertson, Claudia S.; McCarthy, James J.

    2014-01-01

    Multi-modal magnetic resonance imaging (MRI) that included high resolution structural imaging, diffusion tensor imaging (DTI), magnetization transfer ratio (MTR) imaging, and magnetic resonance spectroscopic imaging (MRSI) were performed in mild traumatic brain injury (mTBI) patients with negative computed tomographic scans and in an orthopedic-injured (OI) group without concomitant injury to the brain. The OI group served as a comparison group for mTBI. MRI scans were performed both in the acute phase of injury (~24 h) and at follow-up (~90 days). DTI data was analyzed using tract based spatial statistics (TBSS). Global and regional atrophies were calculated using tensor-based morphometry (TBM). MTR values were calculated using the standard method. MRSI was analyzed using LC Model. At the initial scan, the mean diffusivity (MD) was significantly higher in the mTBI cohort relative to the comparison group in several white matter (WM) regions that included internal capsule, external capsule, superior corona radiata, anterior corona radiata, posterior corona radiata, inferior fronto-occipital fasciculus, inferior longitudinal fasciculus, forceps major and forceps minor of the corpus callosum, superior longitudinal fasciculus, and corticospinal tract in the right hemisphere. TBSS analysis failed to detect significant differences in any DTI measures between the initial and follow-up scans either in the mTBI or OI group. No significant differences were found in MRSI, MTR or morphometry between the mTBI and OI cohorts either at the initial or follow-up scans with or without family wise error (FWE) correction. Our study suggests that a number of WM tracts are affected in mTBI in the acute phase of injury and that these changes disappear by 90 days. This study also suggests that none of the MRI-modalities used in this study, with the exception of DTI, is sensitive in detecting changes in the acute phase of mTBI. PMID:25610770

  7. Multi-modal MRI of mild traumatic brain injury.

    PubMed

    Narayana, Ponnada A; Yu, Xintian; Hasan, Khader M; Wilde, Elisabeth A; Levin, Harvey S; Hunter, Jill V; Miller, Emmy R; Patel, Vipul Kumar S; Robertson, Claudia S; McCarthy, James J

    2015-01-01

    Multi-modal magnetic resonance imaging (MRI) that included high resolution structural imaging, diffusion tensor imaging (DTI), magnetization transfer ratio (MTR) imaging, and magnetic resonance spectroscopic imaging (MRSI) were performed in mild traumatic brain injury (mTBI) patients with negative computed tomographic scans and in an orthopedic-injured (OI) group without concomitant injury to the brain. The OI group served as a comparison group for mTBI. MRI scans were performed both in the acute phase of injury (~24 h) and at follow-up (~90 days). DTI data was analyzed using tract based spatial statistics (TBSS). Global and regional atrophies were calculated using tensor-based morphometry (TBM). MTR values were calculated using the standard method. MRSI was analyzed using LC Model. At the initial scan, the mean diffusivity (MD) was significantly higher in the mTBI cohort relative to the comparison group in several white matter (WM) regions that included internal capsule, external capsule, superior corona radiata, anterior corona radiata, posterior corona radiata, inferior fronto-occipital fasciculus, inferior longitudinal fasciculus, forceps major and forceps minor of the corpus callosum, superior longitudinal fasciculus, and corticospinal tract in the right hemisphere. TBSS analysis failed to detect significant differences in any DTI measures between the initial and follow-up scans either in the mTBI or OI group. No significant differences were found in MRSI, MTR or morphometry between the mTBI and OI cohorts either at the initial or follow-up scans with or without family wise error (FWE) correction. Our study suggests that a number of WM tracts are affected in mTBI in the acute phase of injury and that these changes disappear by 90 days. This study also suggests that none of the MRI-modalities used in this study, with the exception of DTI, is sensitive in detecting changes in the acute phase of mTBI. PMID:25610770

  8. The right hemisphere is dominant in organization of visual search-A study in stroke patients.

    PubMed

    Ten Brink, Antonia F; Matthijs Biesbroek, J; Kuijf, Hugo J; Van der Stigchel, Stefan; Oort, Quirien; Visser-Meily, Johanna M A; Nijboer, Tanja C W

    2016-05-01

    Cancellation tasks are widely used for diagnosis of lateralized attentional deficits in stroke patients. A disorganized fashion of target cancellation has been hypothesized to reflect disturbed spatial exploration. In the current study we aimed to examine which lesion locations result in disorganized visual search during cancellation tasks, in order to determine which brain areas are involved in search organization. A computerized shape cancellation task was administered in 78 stroke patients. As an index for search organization, the amount of intersections of paths between consecutive crossed targets was computed (i.e., intersections rate). This measure is known to accurately depict disorganized visual search in a stroke population. Ischemic lesions were delineated on CT or MRI images. Assumption-free voxel-based lesion-symptom mapping and region of interest-based analyses were used to determine the grey and white matter anatomical correlates of the intersections rate as a continuous measure. The right lateral occipital cortex, superior parietal lobule, postcentral gyrus, superior temporal gyrus, middle temporal gyrus, supramarginal gyrus, inferior longitudinal fasciculus, first branch of the superior longitudinal fasciculus (SLF I), and the inferior fronto-occipital fasciculus, were related to search organization. To conclude, a clear right hemispheric dominance for search organization was revealed. Further, the correlates of disorganized search overlap with regions that have previously been associated with conjunctive search and spatial working memory. This suggests that disorganized visual search is caused by disturbed spatial processes, rather than deficits in high level executive function or planning, which would be expected to be more related to frontal regions. PMID:26876010

  9. Covert face recognition without the fusiform-temporal pathways.

    PubMed

    Valdés-Sosa, Mitchell; Bobes, Maria A; Quiñones, Ileana; Garcia, Lorna; Valdes-Hernandez, Pedro A; Iturria, Yasser; Melie-Garcia, Lester; Lopera, Francisco; Asencio, José

    2011-08-01

    Patients with prosopagnosia are unable to recognize faces consciously, but when tested indirectly they can reveal residual identification abilities. The neural circuitry underlying this covert recognition is still unknown. One candidate for this function is the partial survival of a pathway linking the fusiform face area (FFA) and anterior-inferior temporal (AIT) cortex, which has been shown to be essential for conscious face identification. Here we performed functional magnetic, and diffusion tensor imaging in FE, a patient with severe prosopagnosia, with the goal of identifying the neural substrates of his robust covert face recognition. FE presented massive bilateral lesions in the fusiform gyri that eliminated both FFAs, and also disrupted the fibers within the inferior longitudinal fasciculi that link the visual areas with the AITs and medial temporal lobes. Therefore participation of the fusiform-temporal pathway in his covert recognition was precluded. However, face-selective activations were found bilaterally in his occipital gyri and in his extended face system (posterior cingulate and orbitofrontal areas), the latter with larger responses for previously-known faces than for faces of strangers. In the right hemisphere, these surviving face selective-areas were connected via a partially persevered inferior fronto-occipital fasciculus. This suggests an alternative occipito-frontal pathway, absent from current models of face processing, that could explain the patient's covert recognition while also playing a role in unconscious processing during normal cognition. PMID:21570471

  10. Cerebral white matter integrity in children with active versus remitted epilepsy 5 years after diagnosis

    PubMed Central

    Amarreh, Ishmael; Dabbs, Kevin; Jackson, Daren C.; Jones, Jana E.; Meyerand, Mary E.; Stafstrom, Carl E.; Hsu, David A; Seidenberg, Michael; Hermann, Bruce P.

    2014-01-01

    Introduction Diffusion Tensor Imaging (DTI) studies have reported white matter abnormalities in childhood-onset epilepsy, but the mechanisms and timing underlying these abnormalities, and their resolution, are not well understood. This study examined white matter integrity in children with active versus remitted epilepsy. Methods Tract-Based Spatial Statistics (TBSS) was used to examine whole-brain DTI indices of fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD) and radial diffusivity (RD) in 20 children with epilepsy 5–6 years after diagnosis, compared to 29 healthy controls. To determine the status of white matter following cessation of seizures, participants with epilepsy were classified as active versus remitted and comparisons included: (1) controls vs. all children with epilepsy, (2) controls vs. children with remitted seizures, (3) controls vs. children with active seizures, and (4) children with active vs. remitted epilepsy. Results In the active compared to remitted epilepsy group, significantly higher FA and lower MD, AD and RD values were dispersed in the internal capsule, cingulum, body of the corpus callosum, superior corona radiata and superior fronto-occipital fasciculus. Similar differences were found between the active epilepsy and the control group. There were no significant differences between the remitted epilepsy and control groups. Conclusion Children with active epilepsy differed in white matter integrity compared to children with remitted epilepsy and healthy controls. It remains to be determined whether these findings represent the outcomes of seizure remission versus an initial biomarker for those children who will ultimately have intractable epilepsy. PMID:24148888

  11. Structural correlates of facial emotion recognition deficits in Parkinson's disease patients.

    PubMed

    Baggio, H C; Segura, B; Ibarretxe-Bilbao, N; Valldeoriola, F; Marti, M J; Compta, Y; Tolosa, E; Junqué, C

    2012-07-01

    The ability to recognize facial emotion expressions, especially negative ones, is described to be impaired in Parkinson's disease (PD) patients. Previous neuroimaging work evaluating the neural substrate of facial emotion recognition (FER) in healthy and pathological subjects has mostly focused on functional changes. This study was designed to evaluate gray matter (GM) and white matter (WM) correlates of FER in a large sample of PD. Thirty-nine PD patients and 23 healthy controls (HC) were tested with the Ekman 60 test for FER and with magnetic resonance imaging. Effects of associated depressive symptoms were taken into account. In accordance with previous studies, PD patients performed significantly worse in recognizing sadness, anger and disgust. In PD patients, voxel-based morphometry analysis revealed areas of positive correlation between individual emotion recognition and GM volume: in the right orbitofrontal cortex, amygdala and postcentral gyrus and sadness identification; in the right occipital fusiform gyrus, ventral striatum and subgenual cortex and anger identification, and in the anterior cingulate cortex (ACC) and disgust identification. WM analysis through diffusion tensor imaging revealed significant positive correlations between fractional anisotropy levels in the frontal portion of the right inferior fronto-occipital fasciculus and the performance in the identification of sadness. These findings shed light on the structural neural bases of the deficits presented by PD patients in this skill. PMID:22640663

  12. White Matter Integrity is Reduced in Bulimia Nervosa

    PubMed Central

    Mettler, Lisa N.; Shott, Megan E.; Pryor, Tamara; Yang, Tony T.; Frank, Guido K.W.

    2013-01-01

    Objective To investigate brain white matter (WM) functionality in bulimia nervosa (BN) in relation to anxiety. Method Twenty-one control (CW, mean age 27±7 years) and 20 BN women (mean age 25±5 years) underwent brain diffusion tensor imaging (DTI) to measure fractional anisotropy (FA; an indication of WM axon integrity) and the apparent diffusion coefficient (ADC; reflecting WM cell damage). Results FA was decreased in BN in the bilateral corona radiata extending into the posterior limb of the internal capsule, the corpus callosum, the right sub-insular white matter and right fornix. In CW but not BN trait anxiety correlated negatively with fornix, corpus callosum and left corona radiata FA. ADC was increased in BN compared to CW in the bilateral corona radiata, corpus callosum, inferior fronto-occipital and uncinate fasciculus. Alterations in BN WM functionality were not due to structural brain alterations. Discussion WM integrity is disturbed in BN, especially in the corona radiate, which has been associated with taste and brain reward processing. Whether this is a premorbid condition or an effect from the illness is yet uncertain. The relationships between WM FA and trait anxiety in CW but not BN may suggest that altered WM functionality contributes to high anxious traits in BN. PMID:23354827

  13. Altered fimbria-fornix white matter integrity in anorexia nervosa predicts harm avoidance

    PubMed Central

    Kazlouski, Demitry; Rollin, Michael D.H.; Tregellas, Jason; Shott, Megan E.; Jappe, Leah M.; Hagman, Jennifer O.; Pryor, Tamara; Yang, Tony T.; Frank, Guido K.W.

    2011-01-01

    The eating disorder anorexia nervosa (AN) is associated with high anxiety. The brain mechanisms that drive those behaviors are unknown. In this study we wanted to test whether brain WM integrity is altered in AN, and related to heightened anxiety. Sixteen adult women with AN (mean age 24±7 years) and 17 healthy control women (CW, mean age 25±4 years) underwent diffusion tensor imaging (DTI) of the brain. The DTI brain images were used to calculate the fractional anisotropy (FA) of WM tracts, which is a measure for WM integrity. AN individuals compared to CW showed clusters of significantly reduced FA (p<0.05, corrected) in the bilateral fimbria-fornix, fronto-occipital fasciculus, as well as posterior cingulum WM. In the AN group, Harm Avoidance was predicted by left (F=5.8, Beta=?0.54, p<0.03) and right (F=6.0, Beta=?0.55, p<0.03) fimbria-fornix FA. Those findings were not due to WM volume deficits in AN. This study indicates that WM integrity is abnormal in AN in limbic and association pathways, which could contribute to disturbed feeding, emotion processing and body perception in AN. The prediction of Harm Avoidance in AN by fimbria-fornix WM integrity suggests that this pathway may be mechanistically involved in high anxiety in AN. PMID:21498054

  14. Sex-linked white matter microstructure of the social and analytic brain.

    PubMed

    Chou, Kun-Hsien; Cheng, Yawei; Chen, I-Yun; Lin, Ching-Po; Chu, Woei-Chyn

    2011-01-01

    Sexual dimorphism in the brain is known to underpin sex differences in neuropsychological behaviors. The white matter (WM) microstructure appears to be coupled with cognitive performances. However, the issues concerning sex differences in WM remains to be determined. This study used the tract-based spatial statistics on diffusion tensor imaging concurrently with the assessments of Empathizing Quotient (EQ) and Systemizing Quotient (SQ) in forty healthy female and forty male adults. Females exhibited greater fractional anisotropy (FA) in the fronto-occipital fasciculus, body of the corpus callosum, and WM underlying the parahippocampal gyrus. Males exhibited larger FA in the bilateral internal capsule, WM underlying the medial frontal gyrus, fusiform gyrus, hippocampus, insula, postcentral gyrus, frontal and temporal lobe. Interestingly, the interaction analysis of dispositional measures by sex showed that females had a positive correlation between FA of the WM underlying the inferior parietal lobule and superior temporal gyrus and EQ but a negative correlation between FA of the occipital and postcentral gyrus and SQ. Males displayed the opposite effect. The findings indicate a sexual dimorphism of WM microstructure. Divergent correlations of WM microstructure and neuropsychological behaviors between sexes may account for the higher prevalence of autism spectrum disorders in males. PMID:20633662

  15. Altered tract-specific white matter microstructure is related to poorer cognitive performance: The Rotterdam Study.

    PubMed

    Cremers, Lotte G M; de Groot, Marius; Hofman, Albert; Krestin, Gabriel P; van der Lugt, Aad; Niessen, Wiro J; Vernooij, Meike W; Ikram, M Arfan

    2016-03-01

    White matter microstructural integrity has been related to cognition. Yet, the potential role of specific white matter tracts on top of a global white matter effect remains unclear, especially when considering specific cognitive domains. Therefore, we determined the tract-specific effect of white matter microstructure on global cognition and specific cognitive domains. In 4400 nondemented and stroke-free participants (mean age 63.7 years, 55.5% women), we obtained diffusion magnetic resonance imaging parameters (fractional anisotropy and mean diffusivity) in 14 white matter tracts using probabilistic tractography and assessed cognitive performance with a cognitive test battery. Tract-specific white matter microstructure in all supratentorial tracts was associated with poorer global cognition. Lower fractional anisotropy in association tracts, primarily the inferior fronto-occipital fasciculus, and higher mean diffusivity in projection tracts, in particular the posterior thalamic radiation, most strongly related to poorer cognition. Altered white matter microstructure related to poorer information processing speed, executive functioning, and motor speed, but not to memory. Tract-specific microstructural changes may aid in better understanding the mechanism of cognitive impairment and neurodegenerative diseases. PMID:26923407

  16. Relationship of a variant in the NTRK1 gene to white matter microstructure in young adults

    PubMed Central

    Braskie, Meredith N; Jahanshad, Neda; Stein, Jason L; Barysheva, Marina; Johnson, Kori; McMahon, Katie L; de Zubicaray, Greig I; Martin, Nicholas G; Wright, Margaret J; Ringman, John M; Toga, Arthur W; Thompson, Paul M

    2012-01-01

    The NTRK1 gene (also known as TRKA) encodes a high affinity receptor for NGF, a neurotrophin involved in nervous system development and myelination. NTRK1 has been implicated in neurological function via links between the T allele at rs6336 (NTRK1-T) and schizophrenia risk. A variant in the neurotrophin gene, BDNF, was previously associated with white matter integrity in young adults, highlighting the importance of neurotrophins to white matter development. We hypothesized that NTRK1-T would relate to lower FA in healthy adults. We scanned 391 healthy adult human twins and their siblings (mean age: 23.6 ± 2.2 years; 31 NTRK1-T carriers, 360 non-carriers) using 105-gradient diffusion tensor imaging at 4 Tesla. We evaluated in brain white matter how NTRK1-T and NTRK1 rs4661063 allele A (rs4661063-A, which is in moderate linkage disequilibrium with rs6336) related to voxelwise fractional anisotropy – a common diffusion tensor imaging measure of white matter microstructure. We used mixed-model regression to control for family relatedness, age, and sex. The sample was split in half to test results reproducibility. The false discovery rate method corrected for voxelwise multiple comparisons. NTRK1-T and rs4661063-A correlated with lower white matter fractional anisotropy, independent of age and sex (multiple comparisons corrected: false discovery rate critical p = 0.038 for NTRK1-T and 0.013 for rs4661063-A). In each half-sample, the NTRK1-T effect was replicated in the cingulum, corpus callosum, superior and inferior longitudinal fasciculi, inferior fronto-occipital fasciculus, superior corona radiata, and uncinate fasciculus. Our results suggest that NTRK1-T is important for developing white matter microstructure. PMID:22539856

  17. Genetic influences on brain asymmetry: a DTI study of 374 twins and siblings.

    PubMed

    Jahanshad, Neda; Lee, Agatha D; Barysheva, Marina; McMahon, Katie L; de Zubicaray, Greig I; Martin, Nicholas G; Wright, Margaret J; Toga, Arthur W; Thompson, Paul M

    2010-08-15

    Brain asymmetry, or the structural and functional specialization of each brain hemisphere, has fascinated neuroscientists for over a century. Even so, genetic and environmental factors that influence brain asymmetry are largely unknown. Diffusion tensor imaging (DTI) now allows asymmetry to be studied at a microscopic scale by examining differences in fiber characteristics across hemispheres rather than differences in structure shapes and volumes. Here we analyzed 4Tesla DTI scans from 374 healthy adults, including 60 monozygotic twin pairs, 45 same-sex dizygotic pairs, and 164 mixed-sex DZ twins and their siblings; mean age: 24.4years+/-1.9 SD). All DTI scans were nonlinearly aligned to a geometrically-symmetric, population-based image template. We computed voxel-wise maps of significant asymmetries (left/right differences) for common diffusion measures that reflect fiber integrity (fractional and geodesic anisotropy; FA, GA and mean diffusivity, MD). In quantitative genetic models computed from all same-sex twin pairs (N=210 subjects), genetic factors accounted for 33% of the variance in asymmetry for the inferior fronto-occipital fasciculus, 37% for the anterior thalamic radiation, and 20% for the forceps major and uncinate fasciculus (all L>R). Shared environmental factors accounted for around 15% of the variance in asymmetry for the cortico-spinal tract (R>L) and about 10% for the forceps minor (L>R). Sex differences in asymmetry (men>women) were significant, and were greatest in regions with prominent FA asymmetries. These maps identify heritable DTI-derived features, and may empower genome-wide searches for genetic polymorphisms that influence brain asymmetry. PMID:20430102

  18. Distinct loci of lexical and semantic access deficits in aphasia: Evidence from voxel-based lesion-symptom mapping and diffusion tensor imaging.

    PubMed

    Harvey, Denise Y; Schnur, Tatiana T

    2015-06-01

    Naming pictures and matching words to pictures belonging to the same semantic category negatively affects language production and comprehension. By most accounts, semantic interference arises when accessing lexical representations in naming (e.g., Damian, Vigliocco, & Levelt, 2001) and semantic representations in comprehension (e.g., Forde & Humphreys, 1997). Further, damage to the left inferior frontal gyrus (LIFG), a region implicated in cognitive control, results in increasing semantic interference when items repeat across cycles in both language production and comprehension (Jefferies, Baker, Doran, & Lambon Ralph, 2007). This generates the prediction that the LIFG via white matter connections supports resolution of semantic interference arising from different loci (lexical vs semantic) in the temporal lobe. However, it remains unclear whether the cognitive and neural mechanisms that resolve semantic interference are the same across tasks. Thus, we examined which gray matter structures [using whole brain and region of interest (ROI) approaches] and white matter connections (using deterministic tractography) when damaged impact semantic interference and its increase across cycles when repeatedly producing and understanding words in 15 speakers with varying lexical-semantic deficits from left hemisphere stroke. We found that damage to distinct brain regions, the posterior versus anterior temporal lobe, was associated with semantic interference (collapsed across cycles) in naming and comprehension, respectively. Further, those with LIFG damage compared to those without exhibited marginally larger increases in semantic interference across cycles in naming but not comprehension. Lastly, the inferior fronto-occipital fasciculus, connecting the LIFG with posterior temporal lobe, related to semantic interference in naming, whereas the inferior longitudinal fasciculus (ILF), connecting posterior with anterior temporal regions related to semantic interference in comprehension. These neuroanatomical-behavioral findings have implications for models of the lexical-semantic language network by demonstrating that semantic interference in language production and comprehension involves different representations which differentially recruit a cognitive control mechanism for interference resolution. PMID:25880795

  19. A Longitudinal Diffusion Tensor Imaging Study Assessing White Matter Fiber Tracts after Sports-Related Concussion

    PubMed Central

    Murugavel, Murali; Cubon, Valerie; Putukian, Margot; Echemendia, Ruben; Cabrera, Javier; Osherson, Daniel

    2014-01-01

    Abstract The extent of structural injury in sports-related concussion (SRC) is central to the course of recovery, long-term effects, and the decision to return to play. In the present longitudinal study, we used diffusion tensor imaging (DTI) to assess white matter (WM) fiber tract integrity within 2 days, 2 weeks, and 2 months of concussive injury. Participants were right-handed male varsity contact-sport athletes (20.2±1.0 years of age) with a medically diagnosed SRC (no loss of consciousness). They were compared to right-handed male varsity non-contact-sport athletes serving as controls (19.9±1.7 years). We found significantly increased radial diffusivity (RD) in concussed athletes (n=12; paired t-test, tract-based spatial statistics; p<0.025) at 2 days, when compared to the 2-week postinjury time point. The increase was found in a cluster of right hemisphere voxels, spanning the posterior limb of the internal capsule (IC), the retrolenticular part of the IC, the inferior longitudinal fasciculus, the inferior fronto-occipital fasciculus (sagittal stratum), and the anterior thalamic radiation. Post-hoc, univariate, between-group (controls vs. concussed), mixed-effects analysis of the cluster showed significantly higher RD at 2 days (p=0.002), as compared to the controls, with a trend in the same direction at 2 months (p=0.11). Results for fractional anisotropy (FA) in the same cluster showed a similar, but inverted, pattern; FA was decreased at 2 days and at 2 months postinjury, when compared to healthy controls. At 2 weeks postinjury, no statistical differences between concussed and control athletes were found with regard to either RD or FA. These results support the hypothesis of increased RD and reduced FA within 72?h postinjury, followed by recovery that may extend beyond 2 weeks. RD appears to be a sensitive measure of concussive injury. PMID:24786666

  20. Novel DTI Methodology to Detect and Quantify Injured Regions and Affected Brain Pathways in Traumatic Brain Injury

    PubMed Central

    Singh, Manbir; Jeong, Jeongwon; Hwang, Darryl; Sungkarat, Witaya; Gruen, Peter

    2009-01-01

    Purpose To develop and apply DTI based normalization methodology for the detection and quantification of traumatic brain injury (TBI) and the impact of injury along specific brain pathways in: a) individual TBI subjects, and b) a TBI group. Materials and Methods Normalized DTI tractography was conducted in the native space of 12 TBI and 10 age-matched control subjects using the same number of seeds in each subject, distributed at anatomically equivalent locations. Whole-brain tracts from the control group were mapped onto the head of each TBI subject. Differences in the Fractional Anisotropy (FA) maps between each TBI subject and the control group were computed in a common space using a t-test, transformed back to the individual TBI subject's head-space, and thresholded to form Regions of Interest (ROIs) that were used to sort tracts from the control group and the individual TBI subject. Tract-counts for a given ROI in each TBI subject were compared to group mean for the same ROI to quantify impact of injury along affected pathways. Same procedure was used to compare TBI group to control group in a common space. Results Sites of injury within individual TBI subjects and affected pathways included hippocampal/fornix, inferior fronto-occipital, inferior longitudinal fasciculus, corpus callosum (genu and splenium), cortico-spinal tracts and the uncinate fasciculus. Most of these regions were also detected in the group study. Conclusions The DTI normalization methodology presented here enables automatic delineation of ROIs within the heads of individual subjects (or in a group). These ROIs not only localize and quantify the extent of injury, but also quantify the impact of injury on affected pathways in an individual or a group of TBI subjects. PMID:19608369

  1. Connectivity-based whole brain dual parcellation by group ICA reveals tract structures and decreased connectivity in schizophrenia.

    PubMed

    Wu, Lei; Calhoun, Vince D; Jung, Rex E; Caprihan, Arvind

    2015-11-01

    Mapping brain connectivity based on neuroimaging data is a promising new tool for understanding brain structure and function. In this methods paper, we demonstrate that group independent component analysis (GICA) can be used to perform a dual parcellation of the brain based on its connectivity matrix (cmICA). This dual parcellation consists of a set of spatially independent source maps, and a corresponding set of paired dual maps that define the connectivity of each source map to the brain. These dual maps are called the connectivity profiles of the source maps. Traditional analysis of connectivity matrices has been used previously for brain parcellation, but the present method provides additional information on the connectivity of these segmented regions. In this paper, the whole brain structural connectivity matrices were calculated on a 5 mm(3) voxel scale from diffusion imaging data based on the probabilistic tractography method. The effect of the choice of the number of components (30 and 100) and their stability were examined. This method generated a set of spatially independent components that are consistent with the canonical brain tracts provided by previous anatomic descriptions, with the high order model yielding finer segmentations. The corpus-callosum example shows how this method leads to a robust parcellation of a brain structure based on its connectivity properties. We applied cmICA to study structural connectivity differences between a group of schizophrenia subjects and healthy controls. The connectivity profiles at both model orders showed similar regions with reduced connectivity in schizophrenia patients. These regions included forceps major, right inferior fronto-occipital fasciculus, uncinate fasciculus, thalamic radiation, and corticospinal tract. This paper provides a novel unsupervised data-driven framework that summarizes the information in a large global connectivity matrix and tests for brain connectivity differences. It has the potential for capturing important brain changes related to disease in connectivity-based disorders. PMID:26291689

  2. A disconnection account of subjective empathy impairments in diffuse low-grade glioma patients.

    PubMed

    Herbet, Guillaume; Lafargue, Gilles; Moritz-Gasser, Sylvie; Menjot de Champfleur, Nicolas; Costi, Emanuele; Bonnetblanc, François; Duffau, Hugues

    2015-04-01

    Human empathic experience is a multifaceted psychological construct which arises from functional integration of multiple neural networks. Despite accumulating knowledge about the cortical circuitry of empathy, almost nothing is known about the connectivity that may be concerned in conveying empathy-related neural information. To bridge this gap in knowledge, we studied dispositional empathy in a large-sized cohort of 107 patients who had undergone surgery for a diffuse low-grade glioma. The self-report questionnaire used enabled us to obtain a global measure of subjective empathy but also, importantly, to assess the two main components of empathy (cognitive and emotional). Data were processed by combining voxelwise and tractwise lesion-symptom analyses. Several major findings emerged from our analyses. First of all, topological voxelwise analyses were inconclusive. Conversely, tractwise multiple regression analyses, including all major associative white matter pathways as potential predictors, yielded to significant models explaining substantial part of the behavioural variance. Among the main results, we found that disconnection of the left cingulum bundle was a strong predictor of a low cognitive empathy (p<0.0005 Bonferroni-corrected). Similarly, we found that disconnection of the right uncinate fasciculus and the right inferior fronto-occipital fasciculus predicted, respectively, a low (p<0.05 Bonferroni-corrected) and a high (p<0.05 Bonferroni-corrected) subjective empathy. Finally, although we failed to relate emotional empathy to disruption of a specific tract, correlation analyses indicated a positive association between this component of empathy and the volumes of residual lesion infiltration in the right hemisphere (p<0.01). Taken as a whole, these findings provide key fundamental insights into the anatomical connectivity of empathy. They may help to better understand the pathophysiology of empathy impairments in pathological conditions characterized by abnormalities of long-range anatomical connectivity, such as autism spectrum disorders, schizophrenia and fronto-temporal dementia. PMID:25687031

  3. Abnormalities of cortical thickness, subcortical shapes, and white matter integrity in subcortical vascular cognitive impairment.

    PubMed

    Thong, Jamie Yu Jin; Du, Jia; Ratnarajah, Nagulan; Dong, Yanhong; Soon, Hock Wei; Saini, Monica; Tan, Ming Zhen; Ta, Anh Tuan; Chen, Christopher; Qiu, Anqi

    2014-05-01

    Subcortical vascular cognitive impairment (sVCI) is caused by lacunar infarcts or extensive and/or diffuse lesions in the white matter that may disrupt the white matter circuitry connecting cortical and subcortical regions and result in the degeneration of neurons in these regions. This study used structural magnetic resonance imaging (MRI) and high angular resolution diffusion imaging (HARDI) techniques to examine cortical thickness, subcortical shapes, and white matter integrity in mild vascular cognitive impairment no dementia (VCIND Mild) and moderate-to-severe VCI (MSVCI). Our study found that compared to controls (n = 25), VCIND Mild (n = 25), and MSVCI (n = 30) showed thinner cortex predominantly in the frontal cortex. The cortex in MSVCI was thinner in the parietal and lateral temporal cortices than that in VCIND Mild. Moreover, compared to controls, VCIND Mild and MSVCI showed smaller shapes (i.e., volume reduction) in the thalamus, putamen, and globus pallidus and ventricular enlargement. Finally, compared to controls, VCIND Mild, and MSVCI showed an increased mean diffusivity in the white matter, while decreased generalized fractional anisotropy was only found in the MSVCI subjects. The major axonal bundles involved in the white matter abnormalities were mainly toward the frontal regions, including the internal capsule/corona radiata, uncinate fasciculus, and anterior section of the inferior fronto-occipital fasciculus, and were anatomically connected to the affected cortical and subcortical structures. Our findings suggest that abnormalities in cortical, subcortical, and white matter morphology in sVCI occur in anatomically connected structures, and that abnormalities progress along a similar trajectory from the mild to moderate and severe conditions. PMID:23861356

  4. The Microstructural Status of the Corpus Callosum Is Associated with the Degree of Motor Function and Neurological Deficit in Stroke Patients

    PubMed Central

    Liang, Fanrong; Huang, Wenhua

    2015-01-01

    Human neuroimaging studies and animal models have suggested that white matter damage from ischemic stroke leads to the functional and structural reorganization of perilesional and remote brain regions. However, the quantitative relationship between the transcallosal tract integrity and clinical motor performance score after stroke remains unexplored. The current study employed a tract-based spatial statistics (TBSS) analysis on diffusion tensor imaging (DTI) to investigate the relationship between white matter diffusivity changes and the clinical scores in stroke patients. Probabilistic fiber tracking was also used to identify structural connectivity patterns in the patients. Thirteen ischemic stroke patients and fifteen healthy control subjects participated in this study. TBSS analyses showed that the corpus callosum (CC) and bilateral corticospinal tracts (CST) in the stroke patients exhibited significantly decreased fractional anisotropy and increased axial and radial diffusivity compared with those of the controls. Correlation analyses revealed that the motor and neurological deficit scores in the stroke patients were associated with the value of diffusivity indices in the CC. Compared with the healthy control group, probabilistic fiber tracking analyses revealed that significant changes in the inter-hemispheric fiber connections between the left and right motor cortex in the stroke patients were primarily located in the genu and body of the CC, left anterior thalamic radiation and inferior fronto-occipital fasciculus, bilateral CST, anterior/superior corona radiate, cingulum and superior longitudinal fasciculus, strongly suggesting that ischemic induces inter-hemispheric network disturbances and disrupts the white matter fibers connecting motor regions. In conclusion, the results of the present study show that DTI-derived measures in the CC can be used to predict the severity of motor skill and neurological deficit in stroke patients. Changes in structural connectivity pattern tracking between the left and right motor areas, particularly in the body of the CC, might reflect functional reorganization and behavioral deficit. PMID:25875333

  5. Altered Structural and Functional Connectivity in Late Preterm Preadolescence: An Anatomic Seed-Based Study of Resting State Networks Related to the Posteromedial and Lateral Parietal Cortex

    PubMed Central

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

    2015-01-01

    Objective Late preterm birth confers increased risk of developmental delay, academic difficulties and social deficits. The late third trimester may represent a critical period of development of neural networks including the default mode network (DMN), which is essential to normal cognition. Our objective is to identify functional and structural connectivity differences in the posteromedial cortex related to late preterm birth. Methods Thirty-eight preadolescents (ages 9–13; 19 born in the late preterm period (≥32 weeks gestational age) and 19 at term) without access to advanced neonatal care were recruited from a low socioeconomic status community in Brazil. Participants underwent neurocognitive testing, 3-dimensional T1-weighted imaging, diffusion-weighted imaging and resting state functional MRI (RS-fMRI). Seed-based probabilistic diffusion tractography and RS-fMRI analyses were performed using unilateral seeds within the posterior DMN (posterior cingulate cortex, precuneus) and lateral parietal DMN (superior marginal and angular gyri). Results Late preterm children demonstrated increased functional connectivity within the posterior default mode networks and increased anti-correlation with the central-executive network when seeded from the posteromedial cortex (PMC). Key differences were demonstrated between PMC components with increased anti-correlation with the salience network seen only with posterior cingulate cortex seeding but not with precuneus seeding. Probabilistic tractography showed increased streamlines within the right inferior longitudinal fasciculus and inferior fronto-occipital fasciculus within late preterm children while decreased intrahemispheric streamlines were also observed. No significant differences in neurocognitive testing were demonstrated between groups. Conclusion Late preterm preadolescence is associated with altered functional connectivity from the PMC and lateral parietal cortex to known distributed functional cortical networks despite no significant executive neurocognitive differences. Selective increased structural connectivity was observed in the setting of decreased posterior interhemispheric connections. Future work is needed to determine if these findings represent a compensatory adaptation employing alternate neural circuitry or could reflect subtle pathology resulting in emotional processing deficits not seen with neurocognitive testing. PMID:26098888

  6. White matter microstructure in untreated first episode bipolar disorder with psychosis: comparison with schizophrenia

    PubMed Central

    Lu, Lisa H; Zhou, Xiaohong Joe; Keedy, Sarah K; Reilly, James L; Sweeney, John A

    2012-01-01

    Objectives White matter abnormalities have been reported in bipolar disorder. The present study aimed to investigate white matter integrity in untreated first episode patients with psychotic bipolar disorder using diffusion tensor imaging, and to compare observations with those from untreated first episode schizophrenia patients. Methods Fractional anisotropy and mean diffusivity were measured in first episode psychotic patients with bipolar disorder (n = 13) or schizophrenia (n = 21) and healthy individuals (n = 18). Group differences were evaluated using voxel based morphometry. Axial and radial diffusivity were examined in regions with altered fractional anisotropy in post-hoc analyses. Results Patients with bipolar disorder showed lower fractional anisotropy than healthy controls in several white matter tracts. Compared with schizophrenia patients, bipolar disorder patients showed lower fractional anisotropy in the cingulum, internal capsule, posterior corpus callosum, tapetum, and occipital white matter including posterior thalamic radiation and inferior longitudinal fasciculus/inferior fronto-occipital fasciculus. Lower fractional anisotropy in bipolar disorder was characterized by increased radial diffusion rather than axial diffusion along the orientation of fiber tracts. Across several white matter tracts, both patient groups showed greater mean diffusivity than healthy individuals. Conclusions Selectively increased radial diffusivity in bipolar disorder patients suggests structural disorganization in fiber tract coherence of neurodevelopmental origin or alterations in myelin sheaths along fiber tracts. In contrast, increased isotropic diffusion along white matter tracts in schizophrenia patients with alterations in both radial and axial diffusivity suggests increased water content outside of axonal space. Thus, the present results suggest that different pathophysiological mechanisms may underlie white matter microstructural abnormalities in bipolar disorder and schizophrenia. PMID:22085473

  7. Neuroanatomical Correlates of Developmental Dyscalculia: Combined Evidence from Morphometry and Tractography

    PubMed Central

    Rykhlevskaia, Elena; Uddin, Lucina Q.; Kondos, Leeza; Menon, Vinod

    2009-01-01

    Poor mathematical abilities adversely affect academic and career opportunities. The neuroanatomical basis of developmental dyscalculia (DD), a specific learning deficit with prevalence rates exceeding 5%, is poorly understood. We used structural MRI and diffusion tensor imaging (DTI) to examine macro- and micro-structural impairments in 7- to 9-year-old children with DD, compared to a group of typically developing (TD) children matched on age, gender, intelligence, reading abilities and working memory capacity. Voxel-based morphometry (VBM) revealed reduced grey matter (GM) bilaterally in superior parietal lobule, intra-parietal sulcus, fusiform gyrus, parahippocampal gyrus and right anterior temporal cortex in children with DD. VBM analysis also showed reduced white matter (WM) volume in right temporal-parietal cortex. DTI revealed reduced fractional anisotropy (FA) in this WM region, pointing to significant right hemisphere micro-structural impairments. Furthermore, FA in this region was correlated with numerical operations but not verbal mathematical reasoning or word reading. Atlas-based tract mapping identified the inferior longitudinal fasciculus, inferior fronto-occipital fasciculus and caudal forceps major as key pathways impaired in DD. DTI tractography suggests that long-range WM projection fibers linking the right fusiform gyrus with temporal-parietal WM are a specific source of vulnerability in DD. Network and classification analysis suggest that DD in children may be characterized by multiple dysfunctional circuits arising from a core WM deficit. Our findings link GM and WM abnormalities in children with DD and they point to macro- and micro-structural abnormalities in right hemisphere temporal-parietal WM, and pathways associated with it, as key neuroanatomical correlates of DD. PMID:20046827

  8. Disrupted white matter connectivity underlying developmental dyslexia: A machine learning approach.

    PubMed

    Cui, Zaixu; Xia, Zhichao; Su, Mengmeng; Shu, Hua; Gong, Gaolang

    2016-04-01

    Developmental dyslexia has been hypothesized to result from multiple causes and exhibit multiple manifestations, implying a distributed multidimensional effect on human brain. The disruption of specific white-matter (WM) tracts/regions has been observed in dyslexic children. However, it remains unknown if developmental dyslexia affects the human brain WM in a multidimensional manner. Being a natural tool for evaluating this hypothesis, the multivariate machine learning approach was applied in this study to compare 28 school-aged dyslexic children with 33 age-matched controls. Structural magnetic resonance imaging (MRI) and diffusion tensor imaging were acquired to extract five multitype WM features at a regional level: white matter volume, fractional anisotropy, mean diffusivity, axial diffusivity, and radial diffusivity. A linear support vector machine (LSVM) classifier achieved an accuracy of 83.61% using these MRI features to distinguish dyslexic children from controls. Notably, the most discriminative features that contributed to the classification were primarily associated with WM regions within the putative reading network/system (e.g., the superior longitudinal fasciculus, inferior fronto-occipital fasciculus, thalamocortical projections, and corpus callosum), the limbic system (e.g., the cingulum and fornix), and the motor system (e.g., the cerebellar peduncle, corona radiata, and corticospinal tract). These results were well replicated using a logistic regression classifier. These findings provided direct evidence supporting a multidimensional effect of developmental dyslexia on WM connectivity of human brain, and highlighted the involvement of WM tracts/regions beyond the well-recognized reading system in dyslexia. Finally, the discriminating results demonstrated a potential of WM neuroimaging features as imaging markers for identifying dyslexic individuals. Hum Brain Mapp 37:1443-1458, 2016. © 2016 Wiley Periodicals, Inc. PMID:26787263

  9. Repeating with the right hemisphere: reduced interactions between phonological and lexical-semantic systems in crossed aphasia?

    PubMed Central

    De-Torres, Irene; Dávila, Guadalupe; Berthier, Marcelo L.; Walsh, Seán Froudist; Moreno-Torres, Ignacio; Ruiz-Cruces, Rafael

    2013-01-01

    Knowledge on the patterns of repetition amongst individuals who develop language deficits in association with right hemisphere lesions (crossed aphasia) is very limited. Available data indicate that repetition in some crossed aphasics experiencing phonological processing deficits is not heavily influenced by lexical-semantic variables (lexicality, imageability, and frequency) as is regularly reported in phonologically-impaired cases with left hemisphere damage. Moreover, in view of the fact that crossed aphasia is rare, information on the role of right cortical areas and white matter tracts underpinning language repetition deficits is scarce. In this study, repetition performance was assessed in two patients with crossed conduction aphasia and striatal/capsular vascular lesions encompassing the right arcuate fasciculus (AF) and inferior frontal-occipital fasciculus (IFOF), the temporal stem and the white matter underneath the supramarginal gyrus. Both patients showed lexicality effects repeating better words than non-words, but manipulation of other lexical-semantic variables exerted less influence on repetition performance. Imageability and frequency effects, production of meaning-based paraphrases during sentence repetition, or better performance on repeating novel sentences than overlearned clichés were hardly ever observed in these two patients. In one patient, diffusion tensor imaging disclosed damage to the right long direct segment of the AF and IFOF with relative sparing of the anterior indirect and posterior segments of the AF, together with fully developed left perisylvian white matter pathways. These findings suggest that striatal/capsular lesions extending into the right AF and IFOF in some individuals with right hemisphere language dominance are associated with atypical repetition patterns which might reflect reduced interactions between phonological and lexical-semantic processes. PMID:24151460

  10. Reading Impairment in a Patient with Missing Arcuate Fasciculus

    ERIC Educational Resources Information Center

    Rauschecker, Andreas M.; Deutsch, Gayle K.; Ben-Shachar, Michal; Schwartzman, Armin; Perry, Lee M.; Dougherty, Robert F.

    2009-01-01

    We describe the case of a child ("S") who was treated with radiation therapy at age 5 for a recurrent malignant brain tumor. Radiation successfully abolished the tumor but caused radiation-induced tissue necrosis, primarily affecting cerebral white matter. "S" was introduced to us at age 15 because of her profound dyslexia. We assessed cognitive…

  11. Word learning is mediated by the left arcuate fasciculus

    PubMed Central

    López-Barroso, Diana; Catani, Marco; Ripollés, Pablo; Dell'Acqua, Flavio; Rodríguez-Fornells, Antoni; de Diego-Balaguer, Ruth

    2013-01-01

    Human language requires constant learning of new words, leading to the acquisition of an average vocabulary of more than 30,000 words in adult life. The ability to learn new words is highly variable and may rely on the integration between auditory and motor information. Here, we combined diffusion imaging tractography and functional MRI to study whether the strength of anatomical and functional connectivity between auditory and motor language networks is associated with word learning ability. Our results showed that performance in word learning correlates with microstructural properties and strength of functional connectivity of the direct connections between Broca’s and Wernicke’s territories in the left hemisphere. This study suggests that our ability to learn new words relies on an efficient and fast communication between temporal and frontal areas. The absence of these connections in other animals may explain the unique ability of learning words in humans. PMID:23884655

  12. Reading Impairment in a Patient with Missing Arcuate Fasciculus

    ERIC Educational Resources Information Center

    Rauschecker, Andreas M.; Deutsch, Gayle K.; Ben-Shachar, Michal; Schwartzman, Armin; Perry, Lee M.; Dougherty, Robert F.

    2009-01-01

    We describe the case of a child ("S") who was treated with radiation therapy at age 5 for a recurrent malignant brain tumor. Radiation successfully abolished the tumor but caused radiation-induced tissue necrosis, primarily affecting cerebral white matter. "S" was introduced to us at age 15 because of her profound dyslexia. We assessed cognitive…

  13. Regional vulnerability of longitudinal cortical association connectivity

    PubMed Central

    Ceschin, Rafael; Lee, Vince K.; Schmithorst, Vince; Panigrahy, Ashok

    2015-01-01

    Preterm born children with spastic diplegia type of cerebral palsy and white matter injury or periventricular leukomalacia (PVL), are known to have motor, visual and cognitive impairments. Most diffusion tensor imaging (DTI) studies performed in this group have demonstrated widespread abnormalities using averaged deterministic tractography and voxel-based DTI measurements. Little is known about structural network correlates of white matter topography and reorganization in preterm cerebral palsy, despite the availability of new therapies and the need for brain imaging biomarkers. Here, we combined novel post-processing methodology of probabilistic tractography data in this preterm cohort to improve spatial and regional delineation of longitudinal cortical association tract abnormalities using an along-tract approach, and compared these data to structural DTI cortical network topology analysis. DTI images were acquired on 16 preterm children with cerebral palsy (mean age 5.6 ± 4) and 75 healthy controls (mean age 5.7 ± 3.4). Despite mean tract analysis, Tract-Based Spatial Statistics (TBSS) and voxel-based morphometry (VBM) demonstrating diffusely reduced fractional anisotropy (FA) reduction in all white matter tracts, the along-tract analysis improved the detection of regional tract vulnerability. The along-tract map-structural network topology correlates revealed two associations: (1) reduced regional posterior–anterior gradient in FA of the longitudinal visual cortical association tracts (inferior fronto-occipital fasciculus, inferior longitudinal fasciculus, optic radiation, posterior thalamic radiation) correlated with reduced posterior–anterior gradient of intra-regional (nodal efficiency) metrics with relative sparing of frontal and temporal regions; and (2) reduced regional FA within frontal–thalamic–striatal white matter pathways (anterior limb/anterior thalamic radiation, superior longitudinal fasciculus and cortical spinal tract) correlated with alteration in eigenvector centrality, clustering coefficient (inter-regional) and participation co-efficient (inter-modular) alterations of frontal–striatal and fronto-limbic nodes suggesting re-organization of these pathways. Both along tract and structural topology network measurements correlated strongly with motor and visual clinical outcome scores. This study shows the value of combining along-tract analysis and structural network topology in depicting not only selective parietal occipital regional vulnerability but also reorganization of frontal–striatal and frontal–limbic pathways in preterm children with cerebral palsy. These finding also support the concept that widespread, but selective posterior–anterior neural network connectivity alterations in preterm children with cerebral palsy likely contribute to the pathogenesis of neurosensory and cognitive impairment in this group. PMID:26509119

  14. Brain networks in posterior cortical atrophy: A single case tractography study and literature review

    PubMed Central

    Migliaccio, Raffaella; Agosta, Federica; Toba, Monica N.; Samri, Dalila; Corlier, Fabian; de Souza, Leonardo C.; Chupin, Marie; Sharman, Michael; Gorno-Tempini, Maria L.; Dubois, Bruno; Filippi, Massimo; Bartolomeo, Paolo

    2016-01-01

    Posterior cortical atrophy (PCA) is rare neurodegenerative dementia, clinically characterized by a progressive decline in higher-visual object and space processing. After a brief review of the literature on the neuroimaging in PCA, here we present a study of the brain structural connectivity in a patient with PCA and progressive isolated visual and visuo-motor signs. Clinical and cognitive data were acquired in a 58-years-old patient (woman, right-handed, disease duration 18 months). Brain structural and diffusion tensor (DT) Magnetic Resonance Imaging (MRI) were obtained. A voxel-based morphometry (VBM) study was performed to explore the pattern of gray matter (GM) atrophy, and a fully automatic segmentation was assessed to obtain the hippocampal volumes. DT MRI-based tractography was used to assess the integrity of long-range white matter (WM) pathways in the patient and in six sex- and age-matched healthy subjects. This PCA patient had a clinical syndrome characterized by left visual neglect, optic ataxia, and left limb apraxia, as well as mild visuo-spatial episodic memory impairment. VBM study showed bilateral posterior GM atrophy with right predominance; DT MRI tractography demonstrated WM damage to the right hemisphere only, including the superior and inferior longitudinal fasciculi and the inferior fronto-occipital fasciculus, as compared to age-matched controls. The homologous left-hemisphere tracts were spared. No difference was found between left and right hippocampal volumes. These data suggest that selective visuo-spatial deficits typical of PCA might not result from cortical damage alone, but by a right-lateralized network-level dysfunction including WM damage along the major visual pathways. PMID:22099855

  15. Abnormal White Matter Integrity in Adolescents with Internet Addiction Disorder: A Tract-Based Spatial Statistics Study

    PubMed Central

    Qin, Lindi; Zhao, Zhimin; Xu, Jianrong; Lei, Hao

    2012-01-01

    Background Internet addiction disorder (IAD) is currently becoming a serious mental health issue around the globe. Previous studies regarding IAD were mainly focused on associated psychological examinations. However, there are few studies on brain structure and function about IAD. In this study, we used diffusion tensor imaging (DTI) to investigate white matter integrity in adolescents with IAD. Methodology/Principal Findings Seventeen IAD subjects and sixteen healthy controls without IAD participated in this study. Whole brain voxel-wise analysis of fractional anisotropy (FA) was performed by tract-based spatial statistics (TBSS) to localize abnormal white matter regions between groups. TBSS demonstrated that IAD had significantly lower FA than controls throughout the brain, including the orbito-frontal white matter, corpus callosum, cingulum, inferior fronto-occipital fasciculus, and corona radiation, internal and external capsules, while exhibiting no areas of higher FA. Volume-of-interest (VOI) analysis was used to detect changes of diffusivity indices in the regions showing FA abnormalities. In most VOIs, FA reductions were caused by an increase in radial diffusivity while no changes in axial diffusivity. Correlation analysis was performed to assess the relationship between FA and behavioral measures within the IAD group. Significantly negative correlations were found between FA values in the left genu of the corpus callosum and the Screen for Child Anxiety Related Emotional Disorders, and between FA values in the left external capsule and the Young's Internet addiction scale. Conclusions Our findings suggest that IAD demonstrated widespread reductions of FA in major white matter pathways and such abnormal white matter structure may be linked to some behavioral impairments. In addition, white matter integrity may serve as a potential new treatment target and FA may be as a qualified biomarker to understand the underlying neural mechanisms of injury or to assess the effectiveness of specific early interventions in IAD. PMID:22253926

  16. White Matter Abnormalities in Pediatric Obsessive-Compulsive Disorder

    PubMed Central

    Gruner, Patricia; Vo, An; Ikuta, Toshikazu; Mahon, Katie; Peters, Bart D; Malhotra, Anil K; Ulu?, Aziz M; Szeszko, Philip R

    2012-01-01

    Obsessive-compulsive disorder (OCD) is a prevalent and often severely disabling illness with onset generally in childhood or adolescence. Although white matter deficits have been implicated in the neurobiology of OCD, few studies have been conducted in pediatric patients when the brain is still developing and have examined their functional correlates. In this study, 23 pediatric OCD patients and 23 healthy volunteers, between the ages of 9 and 17 years, matched for sex, age, handedness, and IQ, received a diffusion tensor imaging exam on a 3T GE system and a brief neuropsychological battery tapping executive functions. Patient symptom severity was assessed using the Children's Yale-Brown Obsessive-Compulsive Scale (CY-BOCS). Patients with OCD exhibited significantly greater fractional anisotropy compared to matched controls in the left dorsal cingulum bundle, splenium of the corpus callosum, right corticospinal tract, and left inferior fronto-occipital fasciculus. There were no regions of significantly lower fractional anisotropy in patients compared to controls. Higher fractional anisotropy in the splenium was significantly correlated with greater obsession severity on the CY-BOCS in the subgroup of psychotropic drug-naïve patients. Among patients, there was a significant association between greater fractional anisotropy in the dorsal cingulum bundle and better performance on measures of response inhibition and cognitive control. The overall findings suggest a pattern of greater directional coherence of white matter tracts in OCD very early in the course of illness, which may serve a compensatory mechanism, at least for response inhibition functions typically subserved by the cingulum bundle. PMID:22871914

  17. Effects of a Balanced Translocation between Chromosomes 1 and 11 Disrupting the DISC1 Locus on White Matter Integrity

    PubMed Central

    Whalley, Heather C.; Dimitrova, Rali; Sprooten, Emma; Dauvermann, Maria R.; Romaniuk, Liana; Duff, Barbara; Watson, Andrew R.; Moorhead, Bill; Bastin, Mark; Semple, Scott I.; Giles, Stephen; Hall, Jeremy; Thomson, Pippa; Roberts, Neil; Hughes, Zoe A.; Brandon, Nick J.; Dunlop, John; Whitcher, Brandon; Blackwood, Douglas H. R.; McIntosh, Andrew M.; Lawrie, Stephen M.

    2015-01-01

    Objective Individuals carrying rare, but biologically informative genetic variants provide a unique opportunity to model major mental illness and inform understanding of disease mechanisms. The rarity of such variations means that their study involves small group numbers, however they are amongst the strongest known genetic risk factors for major mental illness and are likely to have large neural effects. DISC1 (Disrupted in Schizophrenia 1) is a gene containing one such risk variant, identified in a single Scottish family through its disruption by a balanced translocation of chromosomes 1 and 11; t(1;11) (q42.1;q14.3). Method Within the original pedigree, we examined the effects of the t(1;11) translocation on white matter integrity, measured by fractional anisotropy (FA). This included family members with (n = 7) and without (n = 13) the translocation, along with a clinical control sample of patients with psychosis (n = 34), and a group of healthy controls (n = 33). Results We report decreased white matter integrity in five clusters in the genu of the corpus callosum, the right inferior fronto-occipital fasciculus, acoustic radiation and fornix. Analysis of the mixed psychosis group also demonstrated decreased white matter integrity in the above regions. FA values within the corpus callosum correlated significantly with positive psychotic symptom severity. Conclusions We demonstrate that the t(1;11) translocation is associated with reduced white matter integrity in frontal commissural and association fibre tracts. These findings overlap with those shown in affected patients with psychosis and in DISC1 animal models and highlight the value of rare but biologically informative mutations in modeling psychosis. PMID:26102360

  18. In vivo study of cerebral white matter in the dog using diffusion tensor tractography.

    PubMed

    Anaya García, Mitzi Sarahí; Hernández Anaya, Jael Sarahí; Marrufo Meléndez, Oscar; Velázquez Ramírez, José Luis; Palacios Aguiar, Ricardo

    2015-01-01

    Conventional magnetic resonance imaging (MRI) allows investigators and clinicians to observe the anatomy and injuries of the cerebral white matter (CWM) in dogs. However, dynamic images based on the diffusion tensor (DT) technique are required to assess fiber tract integrity of the CWM. Diffusion tensor tractography (DTT) produces a three-dimensional representation in which data are displayed on a colored map obtained from the anisotropy of water molecules in the CWM tracts. Fractional anisotropy (FA) is a value that measures changes in water diffusion, which can occur if the CWM tracts are displaced, disrupted, or infiltrated. The goal of this study was to determine the feasibility of DTT for in vivo examination of the normal appearance of CWM in dogs through visual and quantitative analysis of the most representative CWM tracts. Nine tractographies were performed on healthy dogs using a 3T MRI scanner. T1- and T2-weighted images and DTI were acquired at different planes. Using DTT, three-dimensional reconstructions were obtained. Fractional ansisotropy and apparent diffusion coefficient (ADC) values of the right and left corticospinal tracts, corpus callosum, cingulum, and right and left fronto-occipital fasciculus were determined. Tract reconstructions were similar in 8/9 healthy dogs. Values for FA and ADC were similar in all the dogs. In one dog, tract reconstructions were inhomogeneous; these were displaced because it had larger lateral ventricles. Findings indicated that DTT is a feasible technique for in vivo study of CWM in dogs and that it complements information from conventional MRI. PMID:25288360

  19. IN VIVO STUDY OF CEREBRAL WHITE MATTER IN THE DOG USING DIFFUSION TENSOR TRACTOGRAPHY

    PubMed Central

    Anaya García, Mitzi Sarahí; Hernández Anaya, Jael Sarahí; Marrufo Meléndez, Oscar; Velázquez Ramírez, José Luis; Palacios Aguiar, Ricardo

    2015-01-01

    Conventional magnetic resonance imaging (MRI) allows investigators and clinicians to observe the anatomy and injuries of the cerebral white matter (CWM) in dogs. However, dynamic images based on the diffusion tensor (DT) technique are required to assess fiber tract integrity of the CWM. Diffusion tensor tractography (DTT) produces a three-dimensional representation in which data are displayed on a colored map obtained from the anisotropy of water molecules in the CWM tracts. Fractional anisotropy (FA) is a value that measures changes in water diffusion, which can occur if the CWM tracts are displaced, disrupted, or infiltrated. The goal of this study was to determine the feasibility of DTT for in vivo examination of the normal appearance of CWM in dogs through visual and quantitative analysis of the most representative CWM tracts. Nine tractographies were performed on healthy dogs using a 3T MRI scanner. T1- and T2-weighted images and DTI were acquired at different planes. Using DTT, three-dimensional reconstructions were obtained. Fractional ansisotropy and apparent diffusion coefficient (ADC) values of the right and left corticospinal tracts, corpus callosum, cingulum, and right and left fronto-occipital fasciculus were determined. Tract reconstructions were similar in 8/9 healthy dogs. Values for FA and ADC were similar in all the dogs. In one dog, tract reconstructions were inhomogeneous; these were displaced because it had larger lateral ventricles. Findings indicated that DTT is a feasible technique for in vivo study of CWM in dogs and that it complements information from conventional MRI. PMID:25288360

  20. Shared genetic variance between obesity and white matter integrity in Mexican Americans

    PubMed Central

    Spieker, Elena A.; Kochunov, Peter; Rowland, Laura M.; Sprooten, Emma; Winkler, Anderson M.; Olvera, Rene L.; Almasy, Laura; Duggirala, Ravi; Fox, Peter T.; Blangero, John; Glahn, David C.; Curran, Joanne E.

    2015-01-01

    Obesity is a chronic metabolic disorder that may also lead to reduced white matter integrity, potentially due to shared genetic risk factors. Genetic correlation analyses were conducted in a large cohort of Mexican American families in San Antonio (N = 761, 58% females, ages 18–81 years; 41.3 ± 14.5) from the Genetics of Brain Structure and Function Study. Shared genetic variance was calculated between measures of adiposity [(body mass index (BMI; kg/m2) and waist circumference (WC; in)] and whole-brain and regional measurements of cerebral white matter integrity (fractional anisotropy). Whole-brain average and regional fractional anisotropy values for 10 major white matter tracts were calculated from high angular resolution diffusion tensor imaging data (DTI; 1.7 × 1.7 × 3 mm; 55 directions). Additive genetic factors explained intersubject variance in BMI (heritability, h2 = 0.58), WC (h2 = 0.57), and FA (h2 = 0.49). FA shared significant portions of genetic variance with BMI in the genu (?G = ?0.25), body (?G = ?0.30), and splenium (?G = ?0.26) of the corpus callosum, internal capsule (?G = ?0.29), and thalamic radiation (?G = ?0.31) (all p's = 0.043). The strongest evidence of shared variance was between BMI/WC and FA in the superior fronto-occipital fasciculus (?G = ?0.39, p = 0.020; ?G = ?0.39, p = 0.030), which highlights region-specific variation in neural correlates of obesity. This may suggest that increase in obesity and reduced white matter integrity share common genetic risk factors. PMID:25763009

  1. Diffuse alterations in grey and white matter associated with cognitive impairment in Shwachman–Diamond syndrome: Evidence from a multimodal approach

    PubMed Central

    Perobelli, Sandra; Alessandrini, Franco; Zoccatelli, Giada; Nicolis, Elena; Beltramello, Alberto; Assael, Baroukh M.; Cipolli, Marco

    2015-01-01

    Shwachman–Diamond syndrome is a rare recessive genetic disease caused by mutations in SBDS gene, at chromosome 7q11. Phenotypically, the syndrome is characterized by exocrine pancreatic insufficiency, bone marrow dysfunction, skeletal dysplasia and variable cognitive impairments. Structural brain abnormalities (smaller head circumference and decreased brain volume) have also been reported. No correlation studies between brain abnormalities and neuropsychological features have yet been performed. In this study we investigate neuroanatomical findings, neurofunctional pathways and cognitive functioning of Shwachman–Diamond syndrome subjects compared with healthy controls. To be eligible for inclusion, participants were required to have known SBDS mutations on both alleles, no history of cranial trauma or any standard contraindication to magnetic resonance imaging. Appropriate tests were used to assess cognitive functions. The static images were acquired on a 3 × 0 T magnetic resonance scanner and blood oxygen level-dependent functional magnetic resonance imaging data were collected both during the execution of the Stroop task and at rest. Diffusion tensor imaging was used to assess brain white matter. The Tract-based Spatial Statistics package and probabilistic tractography were used to characterize white matter pathways. Nine participants (5 males), half of all the subjects aged 9–19 years included in the Italian Shwachman–Diamond Syndrome Registry, were evaluated and compared with nine healthy subjects, matched for sex and age. The patients performed less well than norms and controls on cognitive tasks (p = 0.0002). Overall, cortical thickness was greater in the patients, both in the left (+10%) and in the right (+15%) hemisphere, significantly differently increased in the temporal (left and right, p = 0.04), and right parietal (p = 0.03) lobes and in Brodmann area 44 (p = 0.04) of the right frontal lobe. The greatest increases were observed in the left limbic-anterior cingulate cortex (?43%, p < 0.0004). Only in Broca's area in the left hemisphere did the patients show a thinner cortical thickness than that of controls (p = 0.01). Diffusion tensor imaging showed large, significant difference increases in both fractional anisotropy (+37%, p < 0.0001) and mean diffusivity (+35%, p < 0.005); the Tract-based Spatial Statistics analysis identified six abnormal clusters of white matter fibres in the fronto-callosal, right fronto-external capsulae, left fronto-parietal, right pontine, temporo-mesial and left anterior–medial–temporal regions. Brain areas activated during the Stroop task and those active during the resting state, are different, fewer and smaller in patients and correlate with worse performance (p = 0.002). Cognitive impairment in Shwachman–Diamond syndrome subjects is associated with diffuse brain anomalies in the grey matter (verbal skills with BA44 and BA20 in the right hemisphere; perceptual skills with BA5, 37, 20, 21, 42 in the left hemisphere) and white matter connectivity (verbal skills with alterations in the fronto-occipital fasciculus and with the inferior-longitudinal fasciculus; perceptual skills with the arcuate fasciculus, limbic and ponto-cerebellar fasciculus; memory skills with the arcuate fasciculus; executive functions with the anterior cingulated and arcuate fasciculus). PMID:25844324

  2. Diffuse alterations in grey and white matter associated with cognitive impairment in Shwachman-Diamond syndrome: evidence from a multimodal approach.

    PubMed

    Perobelli, Sandra; Alessandrini, Franco; Zoccatelli, Giada; Nicolis, Elena; Beltramello, Alberto; Assael, Baroukh M; Cipolli, Marco

    2015-01-01

    Shwachman-Diamond syndrome is a rare recessive genetic disease caused by mutations in SBDS gene, at chromosome 7q11. Phenotypically, the syndrome is characterized by exocrine pancreatic insufficiency, bone marrow dysfunction, skeletal dysplasia and variable cognitive impairments. Structural brain abnormalities (smaller head circumference and decreased brain volume) have also been reported. No correlation studies between brain abnormalities and neuropsychological features have yet been performed. In this study we investigate neuroanatomical findings, neurofunctional pathways and cognitive functioning of Shwachman-Diamond syndrome subjects compared with healthy controls. To be eligible for inclusion, participants were required to have known SBDS mutations on both alleles, no history of cranial trauma or any standard contraindication to magnetic resonance imaging. Appropriate tests were used to assess cognitive functions. The static images were acquired on a 3 × 0 T magnetic resonance scanner and blood oxygen level-dependent functional magnetic resonance imaging data were collected both during the execution of the Stroop task and at rest. Diffusion tensor imaging was used to assess brain white matter. The Tract-based Spatial Statistics package and probabilistic tractography were used to characterize white matter pathways. Nine participants (5 males), half of all the subjects aged 9-19 years included in the Italian Shwachman-Diamond Syndrome Registry, were evaluated and compared with nine healthy subjects, matched for sex and age. The patients performed less well than norms and controls on cognitive tasks (p = 0.0002). Overall, cortical thickness was greater in the patients, both in the left (+10%) and in the right (+15%) hemisphere, significantly differently increased in the temporal (left and right, p = 0.04), and right parietal (p = 0.03) lobes and in Brodmann area 44 (p = 0.04) of the right frontal lobe. The greatest increases were observed in the left limbic-anterior cingulate cortex (≥43%, p < 0.0004). Only in Broca's area in the left hemisphere did the patients show a thinner cortical thickness than that of controls (p = 0.01). Diffusion tensor imaging showed large, significant difference increases in both fractional anisotropy (+37%, p < 0.0001) and mean diffusivity (+35%, p < 0.005); the Tract-based Spatial Statistics analysis identified six abnormal clusters of white matter fibres in the fronto-callosal, right fronto-external capsulae, left fronto-parietal, right pontine, temporo-mesial and left anterior-medial-temporal regions. Brain areas activated during the Stroop task and those active during the resting state, are different, fewer and smaller in patients and correlate with worse performance (p = 0.002). Cognitive impairment in Shwachman-Diamond syndrome subjects is associated with diffuse brain anomalies in the grey matter (verbal skills with BA44 and BA20 in the right hemisphere; perceptual skills with BA5, 37, 20, 21, 42 in the left hemisphere) and white matter connectivity (verbal skills with alterations in the fronto-occipital fasciculus and with the inferior-longitudinal fasciculus; perceptual skills with the arcuate fasciculus, limbic and ponto-cerebellar fasciculus; memory skills with the arcuate fasciculus; executive functions with the anterior cingulated and arcuate fasciculus). PMID:25844324

  3. Probabilistic maps of the white matter tracts with known associated functions on the neonatal brain atlas: Application to evaluate longitudinal developmental trajectories in term-born and preterm-born infants.

    PubMed

    Akazawa, Kentaro; Chang, Linda; Yamakawa, Robyn; Hayama, Sara; Buchthal, Steven; Alicata, Daniel; Andres, Tamara; Castillo, Deborrah; Oishi, Kumiko; Skranes, Jon; Ernst, Thomas; Oishi, Kenichi

    2016-03-01

    Diffusion tensor imaging (DTI) has been widely used to investigate the development of the neonatal and infant brain, and deviations related to various diseases or medical conditions like preterm birth. In this study, we created a probabilistic map of fiber pathways with known associated functions, on a published neonatal multimodal atlas. The pathways-of-interest include the superficial white matter (SWM) fibers just beneath the specific cytoarchitectonically defined cortical areas, which were difficult to evaluate with existing DTI analysis methods. The Jülich cytoarchitectonic atlas was applied to define cortical areas related to specific brain functions, and the Dynamic Programming (DP) method was applied to delineate the white matter pathways traversing through the SWM. Probabilistic maps were created for pathways related to motor, somatosensory, auditory, visual, and limbic functions, as well as major white matter tracts, such as the corpus callosum, the inferior fronto-occipital fasciculus, and the middle cerebellar peduncle, by delineating these structures in eleven healthy term-born neonates. In order to characterize maturation-related changes in diffusivity measures of these pathways, the probabilistic maps were then applied to DTIs of 49 healthy infants who were longitudinally scanned at three time-points, approximately five weeks apart. First, we investigated the normal developmental pattern based on 19 term-born infants. Next, we analyzed 30 preterm-born infants to identify developmental patterns related to preterm birth. Last, we investigated the difference in diffusion measures between these groups to evaluate the effects of preterm birth on the development of these functional pathways. Term-born and preterm-born infants both demonstrated a time-dependent decrease in diffusivity, indicating postnatal maturation in these pathways, with laterality seen in the corticospinal tract and the optic radiation. The comparison between term- and preterm-born infants indicated higher diffusivity in the preterm-born infants than in the term-born infants in three of these pathways: the body of the corpus callosum; the left inferior longitudinal fasciculus; and the pathway connecting the left primary/secondary visual cortices and the motion-sensitive area in the occipitotemporal visual cortex (V5/MT+). Probabilistic maps provided an opportunity to investigate developmental changes of each white matter pathway. Whether alterations in white matter pathways can predict functional outcomes will be further investigated in a follow-up study. PMID:26712341

  4. White Matter Microstructure in Superior Longitudinal Fasciculus Associated with Spatial Working Memory Performance in Children

    ERIC Educational Resources Information Center

    Vestergaard, Martin; Madsen, Kathrine Skak; Baare, William F. C.; Skimminge, Arnold; Ejersbo, Lisser Rye; Ramsoy, Thomas Z.; Gerlach, Christian; Akeson, Per; Paulson, Olaf B.; Jernigan, Terry L.

    2011-01-01

    During childhood and adolescence, ongoing white matter maturation in the fronto-parietal cortices and connecting fiber tracts is measurable with diffusion-weighted imaging. Important questions remain, however, about the links between these changes and developing cognitive functions. Spatial working memory (SWM) performance improves significantly…

  5. White Matter Microstructure in Superior Longitudinal Fasciculus Associated with Spatial Working Memory Performance in Children

    ERIC Educational Resources Information Center

    Vestergaard, Martin; Madsen, Kathrine Skak; Baare, William F. C.; Skimminge, Arnold; Ejersbo, Lisser Rye; Ramsoy, Thomas Z.; Gerlach, Christian; Akeson, Per; Paulson, Olaf B.; Jernigan, Terry L.

    2011-01-01

    During childhood and adolescence, ongoing white matter maturation in the fronto-parietal cortices and connecting fiber tracts is measurable with diffusion-weighted imaging. Important questions remain, however, about the links between these changes and developing cognitive functions. Spatial working memory (SWM) performance improves significantly…

  6. Beyond the Arcuate Fasciculus: Consensus and Controversy in the Connectional Anatomy of Language

    ERIC Educational Resources Information Center

    Dick, Anthony Steven; Tremblay, Pascale

    2012-01-01

    The growing consensus that language is distributed into large-scale cortical and subcortical networks has brought with it an increasing focus on the connectional anatomy of language, or how particular fibre pathways connect regions within the language network. Understanding connectivity of the language network could provide critical insights into…

  7. Long-Term Cognitive and Behavioral Therapies, Combined with Augmentative Communication, Are Related to Uncinate Fasciculus Integrity in Autism

    ERIC Educational Resources Information Center

    Pardini, Matteo; Elia, Maurizio; Garaci, Francesco G.; Guida, Silvia; Coniglione, Filadelfo; Krueger, Frank; Benassi, Francesca; Gialloreti, Leonardo Emberti

    2012-01-01

    Recent evidence points to white-matter abnormalities as a key factor in autism physiopathology. Using Diffusion Tensor Imaging, we studied white-matter structural properties in a convenience sample of twenty-two subjects with low-functioning autism exposed to long-term augmentative and alternative communication, combined with sessions of cognitive…

  8. Long-Term Cognitive and Behavioral Therapies, Combined with Augmentative Communication, Are Related to Uncinate Fasciculus Integrity in Autism

    ERIC Educational Resources Information Center

    Pardini, Matteo; Elia, Maurizio; Garaci, Francesco G.; Guida, Silvia; Coniglione, Filadelfo; Krueger, Frank; Benassi, Francesca; Gialloreti, Leonardo Emberti

    2012-01-01

    Recent evidence points to white-matter abnormalities as a key factor in autism physiopathology. Using Diffusion Tensor Imaging, we studied white-matter structural properties in a convenience sample of twenty-two subjects with low-functioning autism exposed to long-term augmentative and alternative communication, combined with sessions of cognitive…

  9. Multiple dermoid sinuses of type Vb and IIIb on the head of a Saint Bernard dog

    PubMed Central

    2013-01-01

    Dermoid sinus, a congenital malformation of neural tube development, has been reported in humans and several animal species including dogs. It is typically found in the dorsal midline and commonly occurs in the Rhodesian Ridgeback breed. A case of multiple dermoid sinuses in the fronto-occipital region is described. An 11-month-old, intact female Saint Bernard dog was presented with a 2 day history of discharge from a large irregular subcutaneous mass in the fronto-occipital region. The dog was otherwise healthy. The dog had two circular skin lesions (approximately 4 × 4 and 4 × 2 cm diameter) surrounded by multiple irregular elevated masses. The masses had multiple small openings on the skin surface with tufts of hair protruding from the apertures. The masses were surgically removed, and the diagnosis of multiple dermoid sinuses was confirmed by histological examination. Histopathological examination showed multiple, variably sized, spherical to tubular cysts expanding the dermis and subcutis. Cysts were filled with hair shafts and lamellar keratin and were lined by a stratified squamous epithelium. Sebaceous and apocrine gland adnexal structures were also observed. To the best of our knowledge, this is the first reported case of multiple dermoid sinuses of two different types in the head of a Saint Bernard dog. PMID:24006855

  10. The influence of spontaneous brain oscillations on apparent motion perception.

    PubMed

    Sanders, Lia Lira Olivier; Auksztulewicz, Ryszard; Hohlefeld, Friederike U; Busch, Niko A; Sterzer, Philipp

    2014-11-15

    A good example of inferential processes in perception is long-range apparent motion (AM), the illusory percept of visual motion that occurs when two spatially distinct stationary visual objects are presented in alternating sequence. The AM illusion is strongest at presentation frequencies around 3 Hz. At lower presentation frequencies, the percept varies from trial to trial between AM and sequential alternation, while at higher frequencies perception varies between AM and two simultaneously flickering objects. Previous studies have demonstrated that prestimulus alpha oscillations explain trial-to-trial variability in detection performance for visual stimuli presented at threshold. In the present study, we investigated whether fluctuations of prestimulus alpha oscillations can also account for variations in AM perception. Prestimulus alpha power was stronger when observers reported AM perception in subsequent trials with low presentation frequencies, while at high presentation frequencies there were no significant differences in alpha power preceding AM and veridical flicker perception. Moreover, when observers perceived AM the prestimulus functional connectivity between frontal and occipital channels was increased in the alpha band, as revealed by the imaginary part of coherency, which is insensitive to artefacts from volume conduction. Dynamic causal modelling of steady-state responses revealed that the most likely direction of this fronto-occipital connectivity was from frontal to occipital sources. These results point to a role of ongoing alpha oscillations in the inferential process that gives rise to the perception of AM and suggest that fronto-occipital interactions bias perception towards internally generated predictions. PMID:25109531

  11. Cephalometric Features of Moyamoya Disease: A case control study

    PubMed Central

    Qureshi, Adnan I; Gilani, Waqas I; Gilani, Sarwat I.; Adil, Malik M.

    2014-01-01

    Contribution of authors Adnan I Qureshi, Waqas I Gilani MD, Sarwat I. Gilani MD, Malik M. Adil MD . Equally assisted in the synthesis and discussion of ideas, and share equal responsibility for the information written in the manuscript above. Conflict Of Interest No conflict of interests. Running title Cephalometric Features of Moyamoya Disease Background Moyamoya disease is highly prevalent among patients with syndromes that have unique cephalometric characteristics such as Down syndrome. We performed a case control study to investigate the relationship between cephalometric parameters and Moyamoya disease. Methods Patients [aged 16-82 years] with angiographically confirmed Moyamoya disease who underwent cranial CT scan were analyzed. We identified three controls for each patient who were matched for age (±1 year), gender, and race (white or African American). The fronto-occipital diameter, bi-parietal diameter, and distance between bregma and occiput were measured from the head CT scans of cases and controls. The cephalic index was calculated by determining the ratio between bi-parietal diameter and fronto-occipital diameter and multiplying the value by 100. Results A total of 13 cases of Moyamoya disease and 39 controls were analyzed. The stage of Moyamoya disease in cases was as follows: stage 1 (n=0), stage 2 (n=1), stage 3 (n=4), stage 4 (n=2), stage 5 (n=5) and stage 6 (n=1). There was a significantly greater bi-parietal diameter in Moyamoya disease patients compared with controls (141.5±3.7 mm versus 136.9±5.4 mm, p=0.007). There was a significantly greater fronto-occipital diameter in Moyamoya disease patients compared with controls (186.5±6.5 mm versus 180.2±8.7mm, p=0.02). The distance between bregma and occiput was shorter among cases compared with controls (81.1±6.2 versus 87.5±7.0, p=0.01). Conclusions We observed an association between cephalometric parameters and Moyamoya disease. Further study of the unique cephalometric characteristics among Moyamoya disease patients may provide additional insight into disease occurrence in white and African American populations. PMID:25422708

  12. Heterozygosity and craniofacial dimensions of Zapotec school children from a subsistence community in the valley of Oaxaca, southern Mexico.

    PubMed

    Little, B B; Buschang, P H; Malina, R M

    1991-01-01

    Gene flow is associated with differences in craniofacial and postcranial dimensions among indigenous populations of southern Mexico. This study compares four craniofacial dimensions in 322 children from families which have an average inbreeding coefficient of 0.01 and 36 children from families which have an inbreeding coefficient of zero (more heterozygous) in a Zapotec speaking community. In addition, two indices were computed. With sex and chronological age constant, there is a statistically significant difference between more and less heterozygous children in bizygomatic diameter. Differences in biparietal diameter and fronto-occipital length reflect the same tendency. The differences probably reflect more an effect of heterozygosity on these dimensions than facial dissimilarity of the populations from which the new genetic materials were drawn because gene flow was from related groups of Indians (e.g., Mixtec) in southern Mexico. Hence, midface growth and overall normal size appear to be affected by fluctuation in level of heterozygosity. PMID:2061401

  13. White matter diffusion alterations in normal women at risk of Alzheimer's disease.

    PubMed

    Smith, Charles D; Chebrolu, Himachandra; Andersen, Anders H; Powell, David A; Lovell, Mark A; Xiong, Shuling; Gold, Brian T

    2010-07-01

    Increased white matter mean diffusivity and decreased fractional anisotropy (FA) has been observed in subjects diagnosed with mild cognitive impairment (MCI) and Alzheimer's disease (AD). We sought to determine whether similar alterations of white matter occur in normal individuals at risk of AD. Diffusion tensor images were acquired in 42 cognitively normal right-handed women with both a family history of dementia and at least one apolipoprotein E4 allele. These were compared with images from 23 normal women without either AD risk factor. Group analyses were performed using tract-based spatial statistics. Reduced FA was observed in the fronto-occipital and inferior temporal fasciculi (particularly posteriorly), the splenium of the corpus callosum, subcallosal white matter and the cingulum bundle. These findings demonstrate that specific white matter pathways are altered in normal women at increased risk of AD years before the expected onset of cognitive symptoms. PMID:18801597

  14. State-modulation of cortico-cortical connections underlying normal EEG alpha variants.

    PubMed

    Cantero, J L; Atienza, M; Salas, R M

    Normal electroencephalographic (EEG) alpha variants appear during relaxed wakefulness with closed eyes, drowsiness period at sleep onset, and rapid eye movement (REM) sleep in bursts without arousal signals. Previous results revealed that fronto-occipital and fronto-frontal alpha coherences became weaker from wakefulness to drowsiness, and finally to REM sleep. The present work was aimed at determining whether a generalized or a unidirectional deactivation of the long fronto-occipital fasciculi, previously proposed to be involved in the alpha rhythm generation, could explain the above-mentioned results. Polynomial regression analyses, applied to the change of alpha coherence with distance along the antero-posterior axis, suggested that the anterior and posterior local circuits show a similar level of activation in all brain states. Bivariate partial correlation analyses between local alpha coherences revealed that such local circuits maintain a reciprocal dependency during wakefulness, but unidirectional during drowsiness (anterior-to-posterior, A-P) and REM sleep (posterior-to-anterior, P-A). From these findings, both anterior and posterior cortical structures are suggested as being involved in the generation of the three alpha variants. If the implication of a double cortical generation source (anterior and posterior) of alpha variants is assumed, these two generators seem to maintain a mutual inter-dependency during wakefulness, whereas during the transition to human sleep, the anterior areas work quite independently of the posterior regions. Finally, the occipital structures may be the driving force for the REM-alpha bursts generation, since involvement of frontal regions demonstrated a high dependence on the posterior neural circuits in the genesis of this sleep event. PMID:11134692

  15. Origin of Emotion Effects on ERP Correlates of Emotional Word Processing: The Emotion Duality Approach

    PubMed Central

    Imbir, Kamil Konrad; Jarymowicz, Maria Teresa; Spustek, Tomasz; Kuś, Rafał; Żygierewicz, Jarosław

    2015-01-01

    We distinguish two evaluative systems which evoke automatic and reflective emotions. Automatic emotions are direct reactions to stimuli whereas reflective emotions are always based on verbalized (and often abstract) criteria of evaluation. We conducted an electroencephalography (EEG) study in which 25 women were required to read and respond to emotional words which engaged either the automatic or reflective system. Stimulus words were emotional (positive or negative) and neutral. We found an effect of valence on an early response with dipolar fronto-occipital topography; positive words evoked a higher amplitude response than negative words. We also found that topographically specific differences in the amplitude of the late positive complex were related to the system involved in processing. Emotional stimuli engaging the automatic system were associated with significantly higher amplitudes in the left-parietal region; the response to neutral words was similar regardless of the system engaged. A different pattern of effects was observed in the central region, neutral stimuli engaging the reflective system evoked a higher amplitudes response whereas there was no system effect for emotional stimuli. These differences could not be reduced to effects of differences between the arousing properties and concreteness of the words used as stimuli. PMID:25955719

  16. Structural and effective connectivity reveals potential network-based influences on category-sensitive visual areas

    PubMed Central

    Furl, Nicholas

    2015-01-01

    Visual category perception is thought to depend on brain areas that respond specifically when certain categories are viewed. These category-sensitive areas are often assumed to be “modules” (with some degree of processing autonomy) and to act predominantly on feedforward visual input. This modular view can be complemented by a view that treats brain areas as elements within more complex networks and as influenced by network properties. This network-oriented viewpoint is emerging from studies using either diffusion tensor imaging to map structural connections or effective connectivity analyses to measure how their functional responses influence each other. This literature motivates several hypotheses that predict category-sensitive activity based on network properties. Large, long-range fiber bundles such as inferior fronto-occipital, arcuate and inferior longitudinal fasciculi are associated with behavioral recognition and could play crucial roles in conveying backward influences on visual cortex from anterior temporal and frontal areas. Such backward influences could support top-down functions such as visual search and emotion-based visual modulation. Within visual cortex itself, areas sensitive to different categories appear well-connected (e.g., face areas connect to object- and motion sensitive areas) and their responses can be predicted by backward modulation. Evidence supporting these propositions remains incomplete and underscores the need for better integration of DTI and functional imaging. PMID:25999841

  17. Occipital cortex of blind individuals is functionally coupled with executive control areas of frontal cortex.

    PubMed

    Deen, Ben; Saxe, Rebecca; Bedny, Marina

    2015-08-01

    In congenital blindness, the occipital cortex responds to a range of nonvisual inputs, including tactile, auditory, and linguistic stimuli. Are these changes in functional responses to stimuli accompanied by altered interactions with nonvisual functional networks? To answer this question, we introduce a data-driven method that searches across cortex for functional connectivity differences across groups. Replicating prior work, we find increased fronto-occipital functional connectivity in congenitally blind relative to blindfolded sighted participants. We demonstrate that this heightened connectivity extends over most of occipital cortex but is specific to a subset of regions in the inferior, dorsal, and medial frontal lobe. To assess the functional profile of these frontal areas, we used an n-back working memory task and a sentence comprehension task. We find that, among prefrontal areas with overconnectivity to occipital cortex, one left inferior frontal region responds to language over music. By contrast, the majority of these regions responded to working memory load but not language. These results suggest that in blindness occipital cortex interacts more with working memory systems and raise new questions about the function and mechanism of occipital plasticity. PMID:25803598

  18. Origin of Emotion Effects on ERP Correlates of Emotional Word Processing: The Emotion Duality Approach.

    PubMed

    Imbir, Kamil Konrad; Jarymowicz, Maria Teresa; Spustek, Tomasz; Ku?, Rafa?; ?ygierewicz, Jaros?aw

    2015-01-01

    We distinguish two evaluative systems which evoke automatic and reflective emotions. Automatic emotions are direct reactions to stimuli whereas reflective emotions are always based on verbalized (and often abstract) criteria of evaluation. We conducted an electroencephalography (EEG) study in which 25 women were required to read and respond to emotional words which engaged either the automatic or reflective system. Stimulus words were emotional (positive or negative) and neutral. We found an effect of valence on an early response with dipolar fronto-occipital topography; positive words evoked a higher amplitude response than negative words. We also found that topographically specific differences in the amplitude of the late positive complex were related to the system involved in processing. Emotional stimuli engaging the automatic system were associated with significantly higher amplitudes in the left-parietal region; the response to neutral words was similar regardless of the system engaged. A different pattern of effects was observed in the central region, neutral stimuli engaging the reflective system evoked a higher amplitudes response whereas there was no system effect for emotional stimuli. These differences could not be reduced to effects of differences between the arousing properties and concreteness of the words used as stimuli. PMID:25955719

  19. Functional connectivity in obesity during reward processing.

    PubMed

    García-García, I; Jurado, M A; Garolera, M; Segura, B; Marqués-Iturria, I; Pueyo, R; Vernet-Vernet, M; Sender-Palacios, M J; Sala-Llonch, R; Ariza, M; Narberhaus, A; Junqué, C

    2013-02-01

    Obesity is a health problem that has become a major focus of attention in recent years. There is growing evidence of an association between obesity and differences in reward processing. However, it is not known at present whether these differences are linked exclusively to food, or whether they can be detected in other rewarding stimuli. We compared responses to food, rewarding non-food and neutral pictures in 18 young adults with obesity and 19 normal-weight subjects using independent component analysis. Both groups modulated task-related activity in a plausible way. However, in response to both food and non-food rewarding stimuli, participants with obesity showed weaker connectivity in a network involving activation of frontal and occipital areas and deactivation of the posterior part of the default mode network. In addition, obesity was related with weaker activation of the default mode network and deactivation of frontal and occipital areas while viewing neutral stimuli. Together, our findings suggest that obesity is related to a different allocation of cognitive resources in a fronto-occipital network and in the default mode network. PMID:23103690

  20. Changes in whole-brain functional networks and memory performance in aging.

    PubMed

    Sala-Llonch, Roser; Junqué, Carme; Arenaza-Urquijo, Eider M; Vidal-Piñeiro, Dídac; Valls-Pedret, Cinta; Palacios, Eva M; Domènech, Sara; Salvà, Antoni; Bargalló, Nuria; Bartrés-Faz, David

    2014-10-01

    We used resting-functional magnetic resonance imaging data from 98 healthy older adults to analyze how local and global measures of functional brain connectivity are affected by age, and whether they are related to differences in memory performance. Whole-brain networks were created individually by parcellating the brain into 90 cerebral regions and obtaining pairwise connectivity. First, we studied age-associations in interregional connectivity and their relationship with the length of the connections. Aging was associated with less connectivity in the long-range connections of fronto-parietal and fronto-occipital systems and with higher connectivity of the short-range connections within frontal, parietal, and occipital lobes. We also used the graph theory to measure functional integration and segregation. The pattern of the overall age-related correlations presented positive correlations of average minimum path length (r = 0.380, p = 0.008) and of global clustering coefficients (r = 0.454, p < 0.001), leading to less integrated and more segregated global networks. Main correlations in clustering coefficients were located in the frontal and parietal lobes. Higher clustering coefficients of some areas were related to lower performance in verbal and visual memory functions. In conclusion, we found that older participants showed lower connectivity of long-range connections together with higher functional segregation of these same connections, which appeared to indicate a more local clustering of information processing. Higher local clustering in older participants was negatively related to memory performance. PMID:24814675

  1. White matter alterations in anorexia nervosa: A systematic review of diffusion tensor imaging studies

    PubMed Central

    Martin Monzon, Beatriz; Hay, Phillipa; Foroughi, Nasim; Touyz, Stephen

    2016-01-01

    AIM: To identify findings concerning white matter (WM) fibre microstructural alterations in anorexia nervosa (AN). METHODS: A systematic electronic search was undertaken in several databases up to April 2015. The search strategy aimed to locate all studies published in English or Spanish that included participants with AN and which investigated WM using diffusion tensor imaging (DTI). Trials were assessed for quality assessment according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses checklist and a published quality index guideline. RESULTS: A total of 6 studies met the inclusion criteria, four of people in the acute state of the illness, one included both recovered and unwell participants, and one included people who had recovered. Participants were female with ages ranging from 14 to 29 years. All studies but one measured a range of psychopathological features. Fractional anisotropy and mean diffusivity were the main DTI correlates reported. Alterations were reported in a range of WM structures of the limbic system, most often of the fornix and cingulum as well as the fronto-occipital fibre tracts, i.e., regions associated with anxiety, body image and cognitive function. Subtle abnormalities also appeared to persist after recovery. CONCLUSION: This diversity likely reflects the symptom complexity of AN. However, there were few studies, they applied different methodologies, and all were cross-sectional. PMID:27014606

  2. Alterations in diffusion properties of white matter in Williams syndrome

    PubMed Central

    Arlinghaus, Lori R.; Thornton-Wells, Tricia A.; Dykens, Elisabeth M.; Anderson, Adam W.

    2011-01-01

    Diffusion tensor imaging (DTI) was used to investigate the involvement of brain white matter in Williams syndrome (WS), a genetic neurodevelopmental disorder. Whole-brain DTIs were obtained from 16 young adults with WS and 16 normal controls. A voxel-based analysis was performed to compare fractional anisotropy (FA) values between the two groups. A tract-based analysis was also performed to compare FA values between the two groups along two major white matter tracts that pass through the external capsule: the uncinate and inferior fronto-occipital fasciculi. Several regions of both increased and decreased FA were found within major white matter tracts that connect functional regions that have previously been implicated in the cognitive and neurological symptoms of the syndrome. The tract-based analysis provided additional insight into the involvement of specific white matter tracts implicated in the voxel-based analysis within the external capsule. The results from this study support previously reported changes in white matter diffusion properties in WS and demonstrate the potential usefulness for tract-based analysis in future studies of the disorder. PMID:21907520

  3. Early development of synchrony in cortical activations in the human.

    PubMed

    Koolen, N; Dereymaeker, A; Räsänen, O; Jansen, K; Vervisch, J; Matic, V; Naulaers, G; De Vos, M; Van Huffel, S; Vanhatalo, S

    2016-05-13

    Early intermittent cortical activity is thought to play a crucial role in the growth of neuronal network development, and large scale brain networks are known to provide the basis for higher brain functions. Yet, the early development of the large scale synchrony in cortical activations is unknown. Here, we tested the hypothesis that the early intermittent cortical activations seen in the human scalp EEG show a clear developmental course during the last trimester of pregnancy, the period of intensive growth of cortico-cortical connections. We recorded scalp EEG from altogether 22 premature infants at post-menstrual age between 30 and 44weeks, and the early cortical synchrony was quantified using recently introduced activation synchrony index (ASI). The developmental correlations of ASI were computed for individual EEG signals as well as anatomically and mathematically defined spatial subgroups. We report two main findings. First, we observed a robust and statistically significant increase in ASI in all cortical areas. Second, there were significant spatial gradients in the synchrony in fronto-occipital and left-to-right directions. These findings provide evidence that early cortical activity is increasingly synchronized across the neocortex. The ASI-based metrics introduced in our work allow direct translational comparison to in vivo animal models, as well as hold promise for implementation as a functional developmental biomarker in future research on human neonates. PMID:26876605

  4. Genetic Influences of Resting State fMRI Activity in Language-Related Brain Regions in Healthy Controls and Schizophrenia Patients: A Pilot Study

    PubMed Central

    Jamadar, Sharna; Powers, Natalie; Meda, Shashwath; Calhoun, Vince D.; Gelernter, Joel; Gruen, Jeffrey; Pearlson, Godfrey

    2015-01-01

    Individuals with schizophrenia show a broad range of language impairments, similar to those observed in reading disability (RD). Genetic linkage and association studies of RD have identified a number of candidate RD-genes that are associated with neuronal migration. Some individuals with schizophrenia also show evidence of impaired cortical neuronal migration. We have previously linked RD-related genes with gray matter distributions in healthy controls and schizophrenia. The aim of the current study was to extend these structural findings and to examine links between putative RD-genes and functional connectivity of language-related regions in healthy controls (n=27) and schizophrenia (n=28). Parallel independent component analysis (parallel-ICA) was used to examine the relationship between language-related regions extracted from resting-state fMRI and 16 single nucleotide polymorphisms (SNPs) spanning 5 RD-related genes. Parallel-ICA identified four significant fMRI-SNP relationships. A Left Broca-Superior/Inferior Parietal network was related to two KIAA0319 SNPs in controls but not in schizophrenia. For both diagnostic groups, a Broca-Medial Parietal network was related to two DCDC2 SNPs, while a Left Wernicke-Fronto-Occipital network was related to two KIAA0319 SNPs. A Bilateral Wernicke-Fronto-Parietal network was related to one KIAA0319 SNP only in controls. Thus, RD-genes influence functional connectivity in language-related regions, but no RD-gene uniquely affected network function in schizophrenia as compared to controls. This is in contrast with our previous study where RD-genes affected gray matter distribution in some structural networks in schizophrenia but not in controls. Thus these RD-genes may exert a more important influence on structure rather than function of language-related networks in schizophrenia. PMID:22669497

  5. A Diffusion Tensor Imaging Study on the White Matter Skeleton in Individuals with Sports-Related Concussion

    PubMed Central

    Cubon, Valerie A.; Putukian, Margot; Boyer, Cynthia

    2011-01-01

    Abstract Recognizing and managing the effects of cerebral concussion is very challenging, given the discrete symptomatology. Most individuals with sports-related concussion will not score below 15 on the Glasgow Coma Scale, but will present with rapid onset of short-lived neurological impairment, demonstrating no structural changes on traditional magnetic resonance imaging (MRI) and computed tomography (CT) scans. The return-to-play decision is one of the most difficult responsibilities facing the physician, and so far this decision has been primarily based on neurological examination, symptom checklists, and neuropsychological (NP) testing. Diffusion tensor imaging (DTI) may be a more objective tool to assess the severity and recovery of function after concussion. We assessed white matter (WM) fiber tract integrity in varsity level college athletes with sports-related concussion without loss of consciousness, who experienced protracted symptoms for at least 1 month after injury. Evaluation of fractional anisotropy (FA) and mean diffusivity (MD) of the WM skeleton using tract-based spatial statistics (TBSS) revealed a large cluster of significantly increased MD for concussed subjects in several WM fiber tracts in the left hemisphere, including parts of the inferior/superior longitudinal and fronto-occipital fasciculi, the retrolenticular part of the internal capsule, and posterior thalamic and acoustic radiations. Qualitative comparison of average FA and MD suggests that with increasing level of injury severity (ranging from sports-related concussion to severe traumatic brain injury), MD might be more sensitive at detecting mild injury, whereas FA captures more severe injuries. In conclusion, the TBSS analysis used to evaluate diffuse axonal injury of the WM skeleton seems sensitive enough to detect structural changes in sports-related concussion. PMID:21083414

  6. Multimodal Magnetic Resonance Imaging Study of Treatment-Naïve Adults with Attention-Deficit/Hyperactivity Disorder

    PubMed Central

    Chaim, Tiffany M.; Zhang, Tianhao; Zanetti, Marcus V.; da Silva, Maria Aparecida; Louzã, Mário R.; Doshi, Jimit; Serpa, Mauricio H.; Duran, Fabio L. S.; Caetano, Sheila C.; Davatzikos, Christos; Busatto, Geraldo F.

    2014-01-01

    Background Attention-Deficit/Hiperactivity Disorder (ADHD) is a prevalent disorder, but its neuroanatomical circuitry is still relatively understudied, especially in the adult population. The few morphometric magnetic resonance imaging (MRI) and diffusion tensor imaging (DTI) studies available to date have found heterogeneous results. This may be at least partly attributable to some well-known technical limitations of the conventional voxel-based methods usually employed to analyze such neuroimaging data. Moreover, there is a great paucity of imaging studies of adult ADHD to date that have excluded patients with history of use of stimulant medication. Methods A newly validated method named optimally-discriminative voxel-based analysis (ODVBA) was applied to multimodal (structural and DTI) MRI data acquired from 22 treatment-naïve ADHD adults and 19 age- and gender-matched healthy controls (HC). Results Regarding DTI data, we found higher fractional anisotropy in ADHD relative to HC encompassing the white matter (WM) of the bilateral superior frontal gyrus, right middle frontal left gyrus, left postcentral gyrus, bilateral cingulate gyrus, bilateral middle temporal gyrus and right superior temporal gyrus; reductions in trace (a measure of diffusivity) in ADHD relative to HC were also found in fronto-striatal-parieto-occipital circuits, including the right superior frontal gyrus and bilateral middle frontal gyrus, right precentral gyrus, left middle occipital gyrus and bilateral cingulate gyrus, as well as the left body and right splenium of the corpus callosum, right superior corona radiata, and right superior longitudinal and fronto-occipital fasciculi. Volumetric abnormalities in ADHD subjects were found only at a trend level of significance, including reduced gray matter (GM) in the right angular gyrus, and increased GM in the right supplementary motor area and superior frontal gyrus. Conclusions Our results suggest that adult ADHD is associated with neuroanatomical abnormalities mainly affecting the WM microstructure in fronto-parieto-temporal circuits that have been implicated in cognitive, emotional and visuomotor processes. PMID:25310815

  7. Neuroanatomical Dissections of Unilateral Visual Neglect Symptoms: ALE Meta-Analysis of Lesion-Symptom Mapping

    PubMed Central

    Chechlacz, Magdalena; Rotshtein, Pia; Humphreys, Glyn W.

    2012-01-01

    Unilateral visual neglect is commonly defined as impaired ability to attend to stimuli presented on the side of visual space contralateral to the brain lesion. However, behavioral analyses indicate that different neglect symptoms can dissociate. The neuroanatomy of the syndrome has been hotly debated. Some groups have argued that the syndrome is linked to posterior parietal cortex lesions, while others report damage within regions including the superior temporal gyrus, insula, and basal ganglia. Several recent neuroimaging studies provide evidence that heterogeneity in the behavioral symptoms of neglect can be matched by variations in the brain lesions, and that some of the discrepancies across earlier findings might have resulted from the use of different neuropsychological tests and/or varied measures within the same task for diagnosing neglect. In this paper, we review the evidence for dissociations between both the symptoms and the neural substrates of unilateral visual neglect, drawing on ALE (anatomic likelihood estimation) meta-analyses of lesion-symptom mapping studies. Specifically, we examine dissociations between neglect symptoms associated with impaired control of attention across space (in an egocentric frame of reference) and within objects (in an allocentric frame of reference). Results of ALE meta-analyses indicated that, while egocentric symptoms are associated with damage within perisylvian network (pre- and postcentral, supramarginal, and superior temporal gyri) and damage within sub-cortical structures, more posterior lesions including the angular, middle temporal, and middle occipital gyri are associated with allocentric symptoms. Furthermore, there was high concurrence in deficits associated with white matter lesions within long association (superior longitudinal, inferior fronto-occipital, and inferior longitudinal fasciculi) and projection (corona radiata and thalamic radiation) pathways, supporting a disconnection account of the syndrome. Using this evidence we argue that different forms of neglect link to both distinct and common patterns of gray and white matter lesions. The findings are discussed in terms of functional accounts of neglect and theoretical models based on computational studies of both normal and impaired attention functions. PMID:22907997

  8. Linked alterations in gray and white matter morphology in adults with high-functioning autism spectrum disorder: A multimodal brain imaging study

    PubMed Central

    Itahashi, Takashi; Yamada, Takashi; Nakamura, Motoaki; Watanabe, Hiromi; Yamagata, Bun; Jimbo, Daiki; Shioda, Seiji; Kuroda, Miho; Toriizuka, Kazuo; Kato, Nobumasa; Hashimoto, Ryuichiro

    2014-01-01

    Growing evidence suggests that a broad range of behavioral anomalies in people with autism spectrum disorder (ASD) can be linked with morphological and functional alterations in the brain. However, the neuroanatomical underpinnings of ASD have been investigated using either structural magnetic resonance imaging (MRI) or diffusion tensor imaging (DTI), and the relationships between abnormalities revealed by these two modalities remain unclear. This study applied a multimodal data-fusion method, known as linked independent component analysis (ICA), to a set of structural MRI and DTI data acquired from 46 adult males with ASD and 46 matched controls in order to elucidate associations between different aspects of atypical neuroanatomy of ASD. Linked ICA identified two composite components that showed significant between-group differences, one of which was significantly correlated with age. In the other component, participants with ASD showed decreased gray matter (GM) volumes in multiple regions, including the bilateral fusiform gyri, bilateral orbitofrontal cortices, and bilateral pre- and post-central gyri. These GM changes were linked with a pattern of decreased fractional anisotropy (FA) in several white matter tracts, such as the bilateral inferior longitudinal fasciculi, bilateral inferior fronto-occipital fasciculi, and bilateral corticospinal tracts. Furthermore, unimodal analysis for DTI data revealed significant reductions of FA along with increased mean diffusivity in those tracts for ASD, providing further evidence of disrupted anatomical connectivity. Taken together, our findings suggest that, in ASD, alterations in different aspects of brain morphology may co-occur in specific brain networks, providing a comprehensive view for understanding the neuroanatomy of this disorder. PMID:25610777

  9. Distributed abnormalities of brain white matter architecture in patients with dominant optic atrophy and OPA1 mutations.

    PubMed

    Rocca, Maria A; Bianchi-Marzoli, Stefania; Messina, Roberta; Cascavilla, Maria Lucia; Zeviani, Massimo; Lamperti, Costanza; Milesi, Jacopo; Carta, Arturo; Cammarata, Gabriella; Leocani, Letizia; Lamantea, Eleonora; Bandello, Francesco; Comi, Giancarlo; Falini, Andrea; Filippi, Massimo

    2015-05-01

    Using advanced MRI techniques, we investigated the presence and topographical distribution of brain grey matter (GM) and white matter (WM) alterations in dominant optic atrophy (DOA) patients with genetically proven OPA1 mutation as well as their correlation with clinical and neuro-ophthalmologic findings. Nineteen DOA patients underwent neurological, neuro-ophthalmologic and brainstem auditory evoked potentials (BAEP) evaluations. Voxel-wise methods were applied to assess regional GM and WM abnormalities in patients compared to 20 healthy controls. Visual acuity was reduced in 16 patients. Six DOA patients (4 with missense mutations) had an abnormal I peripheral component (auditory nerve) at BAEP. Compared to controls, DOA patients had significant atrophy of the optic nerves (p < 0.0001). Voxel-based morphometry (VBM) analysis showed that, compared to controls, DOA patients had significant WM atrophy of the chiasm and optic tracts; whereas no areas of GM atrophy were found. Tract-based spatial statistics (TBSS) analysis showed that compared to controls, DOA patients had significantly lower mean diffusivity, axial and radial diffusivity in the WM of the cerebellum, brainstem, thalamus, fronto-occipital-temporal lobes, including the cingulum, corpus callosum, corticospinal tract and optic radiation bilaterally. No abnormalities of fractional anisotropy were detected. No correlations were found between volumetric and diffusivity abnormalities quantified with MRI and clinical and neuro-ophthalmologic measures of disease severity. Consistently with pathological studies, tissue loss in DOA patients is limited to anterior optic pathways reflecting retinal ganglion cell degeneration. Distributed abnormalities of diffusivity indexes might reflect abnormal intracellular mitochondrial morphology as well as alteration of protein levels due to OPA1 mutations. PMID:25794858

  10. White Matter Fractional Anisotropy Correlates With Speed of Processing and Motor Speed in Young Childhood Cancer Survivors

    SciTech Connect

    Aukema, Eline J.; Oudhuis, Nienke; Vos, Frans M.; Reneman, Liesbeth; Last, Bob F.; Grootenhuis, Martha A.

    2009-07-01

    Purpose: To determine whether childhood medulloblastoma and acute lymphoblastic leukemia (ALL) survivors have decreased white matter fractional anisotropy (WMFA) and whether WMFA is related to the speed of processing and motor speed. Methods and Materials: For this study, 17 patients (6 medulloblastoma, 5 ALL treated with high-dose methotrexate (MTX) (4 x 5 g/m{sup 2}) and 6 with low-dose MTX (3 x 2 g/m{sup 2})) and 17 age-matched controls participated. On a 3.0-T magnetic resonance imaging (MRI) scanner, diffusion tensor imaging (DTI) was performed, and WMFA values were calculated, including specific regions of interest (ROIs), and correlated with the speed of processing and motor speed. Results: Mean WMFA in the patient group, mean age 14 years (range 8.9 - 16.9), was decreased compared with the control group (p = 0.01), as well as WMFA in the right inferior fronto-occipital fasciliculus (IFO) (p = 0.03) and in the genu of the corpus callosum (gCC) (p = 0.01). Based on neurocognitive results, significant positive correlations were present between processing speed and WMFA in the splenium (sCC) (r = 0.53, p = 0.03) and the body of the corpus callosum (bCC) (r = 0.52, p = 0.03), whereas the right IFO WMFA was related to motor speed (r = 0.49, p < 0.05). Conclusions: White matter tracts, using a 3.0-T MRI scanner, show impairment in childhood cancer survivors, medulloblastoma survivors, and also those treated with high doses of MTX. In particular, white matter tracts in the sCC, bCC and right IFO are positively correlated with speed of processing and motor speed.

  11. Axonal deficits in young adults with High Functioning Autism and their impact on processing speed

    PubMed Central

    Lazar, Mariana; Miles, Laura M.; Babb, James S.; Donaldson, Jeffrey B.

    2014-01-01

    Microstructural white matter deficits in Autism Spectrum Disorders (ASD) have been suggested by both histological findings and Diffusion Tensor Imaging (DTI) studies, which show reduced fractional anisotropy (FA) and increased mean diffusivity (MD). However, imaging reports are generally not consistent across studies and the underlying physiological causes of the reported differences in FA and MD remain poorly understood. In this study, we sought to further characterize white matter deficits in ASD by employing an advanced diffusion imaging method, the Diffusional Kurtosis Imaging (DKI), and a two-compartment diffusion model of white matter. This model differentially describes intra- and extra-axonal white matter compartments using Axonal Water Fraction (faxon) a measure reflecting axonal caliber and density, and compartment-specific diffusivity measures. Diagnostic utility of these measures and associations with processing speed performance were also examined. Comparative studies were conducted in 16 young male adults with High Functioning Autism (HFA) and 17 typically developing control participants (TDC). Significantly decreased faxon was observed in HFA compared to the control group in most of the major white matter tracts, including the corpus callosum, cortico-spinal tracts, and superior longitudinal, inferior longitudinal and inferior fronto-occipital fasciculi. Intra-axonal diffusivity (Daxon) was also found to be reduced in some of these regions. Decreased axial extra-axonal diffusivity (ADextra) was noted in the genu of the corpus callosum. Reduced processing speed significantly correlated with decreased faxon and Daxon in several tracts. faxon of the left cortico-spinal tract and superior longitudinal fasciculi showed good accuracy in discriminating the HFA and TDC groups. In conclusion, these findings suggest altered axonal microstructure in young adults with HFA which is associated with reduced processing speed. Compartment-specific diffusion metrics appear to improve specificity and sensitivity to white matter deficits in this population. PMID:24624327

  12. Is Aberrant Functional Connectivity A Psychosis Endophenotype? A Resting State Functional Magnetic Resonance Imaging Study

    PubMed Central

    Khadka, Sabin; Meda, Shashwath A.; Stevens, Michael C.; Glahn, David C.; Calhoun, Vince D.; Sweeney, John A.; Tamminga, Carol A.; Keshavan, Matcheri S.; O’Neil, Kasey; Schretlen, David; Pearlson, Godfrey D.

    2013-01-01

    Background Schizophrenia and bipolar disorder share overlapping symptoms and risk genes. Shared aberrant functional connectivity is hypothesized in both disorders and in relatives. Methods We investigated resting state functional MRI (fMRI) in 70 schizophrenia and 64 psychotic bipolar probands, their respective first-degree relatives (N = 70 and 52) and 118 healthy subjects. We used independent component analysis (ICA) to identify components representing various resting state networks and assessed spatial aspects of functional connectivity within all networks. We first investigated group differences using five-level, one-way analysis of covariance (ANCOVA), followed by post-hoc t-tests within regions displaying ANCOVA group differences and correlation of such functional connectivity measures with symptom ratings to examine clinical relationships. Results Seven different networks revealed abnormalities (five-level one-way ANCOVA, family-wise error correction p < 0.05): (A) fronto-occipital, (B) midbrain/cerebellum, (C) frontal/thalamic/basal ganglia, (D) meso/paralimbic, (E) posterior default mode network, (F) fronto-temporal/paralimbic and (G) sensorimotor networks. Abnormalities in networks B and F were unique to schizophrenia probands only. Furthermore, abnormalities in networks D and E were common to both patient groups. Finally, networks A, C and G showed abnormalities shared by probands and their relative groups. Negative correlation with Positive and Negative Syndrome Scale (PANSS) negative and positive scores were found in regions within network C and F respectively, and positive correlation with PANSS negative scores was found in regions in network D among schizophrenia probands only. Conclusion Schizophrenia, psychotic bipolar probands and their relatives share both unique and overlapping within-network brain connectivity abnormalities, revealing potential psychosis endophenotypes. PMID:23746539

  13. Differences in resting-state fMRI functional network connectivity between schizophrenia and psychotic bipolar probands and their unaffected first-degree relatives

    PubMed Central

    Meda, Shashwath A.; Gill, Adrienne; Stevens, Michael C.; Lorenzoni, Raymond P.; Glahn, David C.; Calhoun, Vince D.; Sweeney, John A.; Tamminga, Carol A.; Keshavan, Matcheri S.; Thaker, Gunvant; Pearlson, Godfrey D.

    2013-01-01

    Background Schizophrenia and bipolar disorder share overlapping symptoms and genetic etiology. Functional brain dysconnectivity is seen in both disorders. Methods We compared 70 schizophrenia and 64 psychotic bipolar probands, their respective unaffected first-degree relatives (N= 70 and 52) and 118 healthy subjects, all group age-, sex- and ethnicity-matched. We used functional network connectivity (FNC) analysis to measure differential connectivity among 16 fMRI RSNs. First, we examined connectivity differences between probands and controls. Next, we probed these dysfunctional connections in relatives for potential endophenotypes. Network connectivity was then correlated with PANSS scores to reveal clinical relationships. Results Three different network pairs were differentially connected in probands (FDR-corrected q<0.05) involving 5 individual resting-state networks: (A) Fronto/Occipital, (B) anterior Default Mode/Prefrontal, (C) Meso/Paralimbic, (D) Fronto-Temporal/Paralimbic & (E) Sensory-motor. One abnormal pair was unique to schizophrenia, (C-E), one unique to bipolar, (C-D) and one (A-B) shared. Two of these 3 combinations (A-B, C-E) were also abnormal in bipolar relatives, but none in schizophrenia relatives (non-significant trend for C-E). The Paralimbic circuit (C-D), that uniquely distinguished bipolar probands, contained multiple mood-relevant regions. Network relationship C-D correlated significantly with PANSS negative scores in bipolar probands and A-B was correlated to PANSS positive and general scores in schizophrenia. Conclusions Schizophrenia and psychotic bipolar probands share several abnormal RSN connections, but there are also unique neural network underpinnings between disorders. We identified specific connections and clinical relationships that may also be candidate psychosis endophenotypes, although these do not segregate straightforwardly with conventional diagnoses. PMID:22401986

  14. A big-world network in ASD: dynamical connectivity analysis reflects a deficit in long-range connections and an excess of short-range connections.

    PubMed

    Barttfeld, Pablo; Wicker, Bruno; Cukier, Sebastián; Navarta, Silvana; Lew, Sergio; Sigman, Mariano

    2011-01-01

    Over the last years, increasing evidence has fuelled the hypothesis that Autism Spectrum Disorder (ASD) is a condition of altered brain functional connectivity. The great majority of these empirical studies relies on functional magnetic resonance imaging (fMRI) which has a relatively poor temporal resolution. Only a handful of studies has examined networks emerging from dynamic coherence at the millisecond resolution and there are no investigations of coherence at the lowest frequencies in the power spectrum-which has recently been shown to reflect long-range cortico-cortical connections. Here we used electroencephalography (EEG) to assess dynamic brain connectivity in ASD focusing in the low-frequency (delta) range. We found that connectivity patterns were distinct in ASD and control populations and reflected a double dissociation: ASD subjects lacked long-range connections, with a most prominent deficit in fronto-occipital connections. Conversely, individuals with ASD showed increased short-range connections in lateral-frontal electrodes. This effect between categories showed a consistent parametric dependency: as ASD severity increased, short-range coherence was more pronounced and long-range coherence decreased. Theoretical arguments have been proposed arguing that distinct patterns of connectivity may result in networks with different efficiency in transmission of information. We show that the networks in ASD subjects have less Clustering coefficient, greater Characteristic Path Length than controls - indicating that the topology of the network departs from small-world behaviour - and greater modularity. Together these results show that delta-band coherence reveal qualitative and quantitative aspects associated with ASD pathology. PMID:21110988

  15. Role of diffusion tensor magnetic resonance tractography in predicting the extent of resection in glioma surgery.

    PubMed

    Castellano, Antonella; Bello, Lorenzo; Michelozzi, Caterina; Gallucci, Marcello; Fava, Enrica; Iadanza, Antonella; Riva, Marco; Casaceli, Giuseppe; Falini, Andrea

    2012-02-01

    Diffusion tensor imaging (DTI) tractography enables the in vivo visualization of the course of white matter tracts inside or around a tumor, and it provides the surgeon with important information in resection planning. This study is aimed at assessing the ability of preoperative DTI tractography in predicting the extent of the resection achievable in surgical removal of gliomas. Patients with low-grade gliomas (LGGs; 46) and high-grade gliomas (HGGs; 27) were studied using a 3T scanner according to a protocol including a morphological study (T2, fluid-attenuated inversion-recovery, T1 sequences) and DTI acquisitions (b = 1000 s/mm(2), 32 gradient directions). Preoperative tractography was performed off-line on the basis of a streamline algorithm, by reconstructing the inferior fronto-occipital (IFO), the superior longitudinal fascicle (SLF), and the corticospinal tract (CST). For each patient, the relationship between each bundle reconstructed and the lesion was analyzed. Initial and residual tumor volumes were measured on preoperative and postoperative 3D fluid-attenuated inversion-recovery images for LGGs and postcontrast T1-weighted scans for HGGs. The presence of intact fascicles was predictive of a better surgical outcome, because these cases showed a higher probability of total resection than did subtotal and partial resection. The presence of infiltrated or displaced CST or infiltrated IFO was predictive of a lower probability of total resection, especially for tumors with preoperative volume <100 cm(3). DTI tractography can thus be considered to be a promising tool for estimating preoperatively the degree of radicality to be reached by surgical resection. This information will aid clinicians in identifying patients who will mostly benefit from surgery. PMID:22015596

  16. Vitamin B12 deficiency: Characterization of psychometrics and MRI morphometrics.

    PubMed

    Hsu, Yen-Hsuan; Huang, Ching-Feng; Lo, Chung-Ping; Wang, Tzu-Lan; Tu, Min-Chien

    2016-02-01

    Objectives Vitamin B12 is essential for the integrity of the central nervous system. However, performances in different cognitive domains relevant to vitamin B12 deficiency remain to be detailed. To date, there have been limited studies that examined the relationships between cognitions and structural neuroimaging in a single cohort of low-vitamin B12 status. The present study aimed to depict psychometrics and magnetic resonance imaging (MRI) morphometrics among patients with vitamin B12 deficiency, and to examine their inter-relations. Methods We compared 34 consecutive patients with vitamin B12 deficiency (serum level ?250 pg/ml) to 34 demographically matched controls by their cognitive performances and morphometric indices of brain MRI. The correlations between psychometrics and morphometrics were analyzed. Results The vitamin B12 deficiency group had lower scores than the controls on total scores of Mini-Mental Status Examination (MMSE) and Cognitive Abilities Screening Instrument (CASI) (both P < 0.05), language (P < 0.01), orientation (P < 0.01), and mental manipulation (P < 0.05). The patients also showed a greater frontal horn ratio than the controls (P < 0.05). Bicaudate ratio, fronto-occipital ratio, uncotemporal index, and normalized interuncal distance all showed a strong correlation with the total score of MMSE and CASI (all P < 0.01). Among these psychometric and morphometric indices, pronounced correlations between bicaudate ratio and long-term memory, mental manipulation, orientation, language, and verbal fluency were noted (all P < 0.01). Discussion Vitamin B12 deficiency is associated with a global cognition decline with language, orientation, and mental manipulation selectively impaired. Preferential atrophy in frontal regions is the main neuroimaging feature. Although the frontal ratio highlights the relevant atrophy among patients, the bicaudate ratio might be the best index on the basis of its strong association with global cognition and related cognitive domains, implying dysfunction of fronto-subcortical circuits as the fundamental pathogenesis related to vitamin B12 deficiency. PMID:26339714

  17. Gravity Influences Top-Down Signals in Visual Processing

    PubMed Central

    Cheron, Guy; Leroy, Axelle; Palmero-Soler, Ernesto; De Saedeleer, Caty; Bengoetxea, Ana; Cebolla, Ana-Maria; Vidal, Manuel; Dan, Bernard; Berthoz, Alain; McIntyre, Joseph

    2014-01-01

    Visual perception is not only based on incoming visual signals but also on information about a multimodal reference frame that incorporates vestibulo-proprioceptive input and motor signals. In addition, top-down modulation of visual processing has previously been demonstrated during cognitive operations including selective attention and working memory tasks. In the absence of a stable gravitational reference, the updating of salient stimuli becomes crucial for successful visuo-spatial behavior by humans in weightlessness. Here we found that visually-evoked potentials triggered by the image of a tunnel just prior to an impending 3D movement in a virtual navigation task were altered in weightlessness aboard the International Space Station, while those evoked by a classical 2D-checkerboard were not. Specifically, the analysis of event-related spectral perturbations and inter-trial phase coherency of these EEG signals recorded in the frontal and occipital areas showed that phase-locking of theta-alpha oscillations was suppressed in weightlessness, but only for the 3D tunnel image. Moreover, analysis of the phase of the coherency demonstrated the existence on Earth of a directional flux in the EEG signals from the frontal to the occipital areas mediating a top-down modulation during the presentation of the image of the 3D tunnel. In weightlessness, this fronto-occipital, top-down control was transformed into a diverging flux from the central areas toward the frontal and occipital areas. These results demonstrate that gravity-related sensory inputs modulate primary visual areas depending on the affordances of the visual scene. PMID:24400069

  18. Prefrontal cortex white matter tracts in prodromal Huntington disease.

    PubMed

    Matsui, Joy T; Vaidya, Jatin G; Wassermann, Demian; Kim, Regina Eunyoung; Magnotta, Vincent A; Johnson, Hans J; Paulsen, Jane S

    2015-10-01

    Huntington disease (HD) is most widely known for its selective degeneration of striatal neurons but there is also growing evidence for white matter (WM) deterioration. The primary objective of this research was to conduct a large-scale analysis using multisite diffusion-weighted imaging (DWI) tractography data to quantify diffusivity properties along major prefrontal cortex WM tracts in prodromal HD. Fifteen international sites participating in the PREDICT-HD study collected imaging and neuropsychological data on gene-positive HD participants without a clinical diagnosis (i.e., prodromal) and gene-negative control participants. The anatomical prefrontal WM tracts of the corpus callosum (PFCC), anterior thalamic radiations (ATRs), inferior fronto-occipital fasciculi (IFO), and uncinate fasciculi (UNC) were identified using streamline tractography of DWI. Within each of these tracts, tensor scalars for fractional anisotropy, mean diffusivity, radial diffusivity, and axial diffusivity coefficients were calculated. We divided prodromal HD subjects into three CAG-age product (CAP) groups having Low, Medium, or High probabilities of onset indexed by genetic exposure. We observed significant differences in WM properties for each of the four anatomical tracts for the High CAP group in comparison to controls. Additionally, the Medium CAP group presented differences in the ATR and IFO in comparison to controls. Furthermore, WM alterations in the PFCC, ATR, and IFO showed robust associations with neuropsychological measures of executive functioning. These results suggest long-range tracts essential for cross-region information transfer show early vulnerability in HD and may explain cognitive problems often present in the prodromal stage. Hum Brain Mapp 36:3717-3732, 2015. © 2015 Wiley Periodicals, Inc. PMID:26179962

  19. Gravity influences top-down signals in visual processing.

    PubMed

    Cheron, Guy; Leroy, Axelle; Palmero-Soler, Ernesto; De Saedeleer, Caty; Bengoetxea, Ana; Cebolla, Ana-Maria; Vidal, Manuel; Dan, Bernard; Berthoz, Alain; McIntyre, Joseph

    2014-01-01

    Visual perception is not only based on incoming visual signals but also on information about a multimodal reference frame that incorporates vestibulo-proprioceptive input and motor signals. In addition, top-down modulation of visual processing has previously been demonstrated during cognitive operations including selective attention and working memory tasks. In the absence of a stable gravitational reference, the updating of salient stimuli becomes crucial for successful visuo-spatial behavior by humans in weightlessness. Here we found that visually-evoked potentials triggered by the image of a tunnel just prior to an impending 3D movement in a virtual navigation task were altered in weightlessness aboard the International Space Station, while those evoked by a classical 2D-checkerboard were not. Specifically, the analysis of event-related spectral perturbations and inter-trial phase coherency of these EEG signals recorded in the frontal and occipital areas showed that phase-locking of theta-alpha oscillations was suppressed in weightlessness, but only for the 3D tunnel image. Moreover, analysis of the phase of the coherency demonstrated the existence on Earth of a directional flux in the EEG signals from the frontal to the occipital areas mediating a top-down modulation during the presentation of the image of the 3D tunnel. In weightlessness, this fronto-occipital, top-down control was transformed into a diverging flux from the central areas toward the frontal and occipital areas. These results demonstrate that gravity-related sensory inputs modulate primary visual areas depending on the affordances of the visual scene. PMID:24400069

  20. White matter integrity and cognition in mild traumatic brain injury following motor vehicle accident.

    PubMed

    Xiong, Kunlin; Zhu, Yongshan; Zhang, Yulong; Yin, Zhiyong; Zhang, Jingna; Qiu, Mingguo; Zhang, Weiguo

    2014-12-01

    The aim of this study is to explore the white matter structure integrity in patients with mild traumatic brain injury (mTBI) using diffusion tensor imaging (DTI), and to analyze the relationship between the white matter structure integrity and cognitive impairment of patients with mTBI. Twenty-five patients with mTBI and 25 healthy control subjects were studied with conventional MR imaging and diffusion tensor imaging. Fractional anisotropy (FA) and mean diffusivity (MD) maps of patients with mTBI were calculated and compared, with these control maps using tract-based spatial statistics (TBSS). Significantly lower fractional anisotropy was found in patients in the uncinate fasciculus, superior longitudinal fasciculus, inferior longitudinal fasciculus, and internal capsule. Mean diffusivity was significantly elevated in the body of corpus callosum, uncinate fasciculus, superior longitudinal fasciculus, and internal capsule in the mTBI group compared with the control group (P<0.05). The mTBI group showed a significant negative correlation between the elevated mean diffusivity of the uncinate fasciculus and the working memory index (WMI) (R(2)=0.51, P<0.05), and the internal capsule of MD values was significantly negatively related to processing speed index (PSI) (R(2)=0.45, P<0.05). There was a positive correlation between the FA value of the uncinate fasciculus and Mini Mental State Examination (MMSE) in the mTBI patient group (R(2)=0.36, P<0.05). TBSS analysis of DTI suggests that patients with mTBI have focal axonal injury, and the pathophysiology is significantly related to the MMSE and IQ of mTBI patients. Diffusion tensor imaging can be a powerful technique for in vivo detection of mTBI, and can help in the diagnosis of patients with mTBI. PMID:25451093

  1. Tract-based Analysis of Magnetization Transfer Ratio and Diffusion Tensor Imaging of the Frontal and Frontotemporal Connections in Schizophrenia

    PubMed Central

    Mandl, René C. W.; Schnack, Hugo G.; Luigjes, Judy; van den Heuvel, Martijn P.; Cahn, Wiepke; Kahn, René S.; Hulshoff Pol, Hilleke E.

    2010-01-01

    Background: In the pathophysiology of schizophrenia, aberrant connectivity between brain regions may be a central feature. Diffusion tensor imaging (DTI) studies have shown altered fractional anisotropy (FA) in white brain matter in schizophrenia. Focal reductions in myelin have been suggested in patients using magnetization transfer ratio (MTR) imaging but to what extent schizophrenia may be related to changes in MTR measured along entire fiber bundles is still unknown. Methods: DTI and MTR images were acquired with a 1.5-T scanner in 40 schizophrenia patients and compared with those of 40 healthy participants. The mean FA and mean MTR were measured along the genu of the corpus callosum and the left and right uncinate fasciculus. Results: A higher mean MTR of 1% was found in the right uncinate fasciculus in patients compared with healthy participants. A significant negative correlation between age and mean FA in the left uncinate fasciculus was found in schizophrenia patients but not in healthy participants. Conclusions: Decreased FA in the left uncinate fasciculus may be more prominent in patients with longer illness duration. The increased mean MTR in the right uncinate fasciculus could reflect a compensatory role for myelin in these fibers or possibly represent aberrant frontotemporal connectivity. PMID:19042913

  2. Anatomical Study of Intrahemispheric Association Fibers in the Brains of Capuchin Monkeys (Sapajus sp.)

    PubMed Central

    Borges, Kellen Christina Malheiros; Nishijo, Hisao; Aversi-Ferreira, Tales Alexandre; Ferreira, Jussara Rocha; Caixeta, Leonardo Ferreira

    2015-01-01

    Previous studies suggest that the complexity of fiber connections in the brain plays a key role in the evolutionary process of the primate brain and behaviors. The patterns of brain fiber systems have been studied in detail in many nonhuman primates, but not in Sapajus sp. Behavioral studies indicated that Sapajus sp. (bearded capuchins) show highly cognitive behaviors such as tool use comparable to those in other nonhuman primates. To compare the brain fiber systems in capuchins with those in other nonhuman primates and humans, the intrahemispheric fibers systems in 24 cerebral hemispheres of Sapajus were dissected by a freezing-thawing procedure. Dissection of the hemispheres in lateral view indicated short arcuate fibers, uncinate fasciculus, and inferior longitudinal fasciculus, while that in a medial view indicated short arcuate fibers, the cingulum united with the superior longitudinal fasciculus, and inferior longitudinal fasciculus. The results showed that the fiber systems in Sapajus are comparable to those in rhesus and humans, except for a lack of independent superior longitudinal fasciculus and cingulum in Sapajus. PMID:26693488

  3. Reduced white matter integrity in attention-deficit hyperactivity disorder

    PubMed Central

    Hamilton, Liberty S.; Levitt, Jennifer G.; O’Neill, Joseph; Alger, Jeffry R.; Luders, Eileen; Phillips, Owen R.; Caplan, Rochelle; Toga, Arthur W.; McCracken, James; Narr, Katherine L.

    2010-01-01

    We used diffusion tensor imaging to investigate fractional anisotropy (FA), a measure of fiber tract integrity, in attention-deficit hyperactivity disorder (ADHD). Using a tract-based atlasing approach on six-direction diffusion tensor imaging data, we examined FA within the cingulum, corpus callosum, corticospinal tract, fornix, optic radiations, superior longitudinal fasciculus, uncinate fasciculus, and the superior and inferior occipitofrontal fasciculi in an all-male sample of17 children and adolescents with ADHD and 16 age-matched controls. ADHD patients had significantly lower FA in the corticospinal tract (P=0.02) and the superior longitudinal fasciculus (P=0.017) compared with controls. Results support that disruptions in motor and attentional networks may contribute toward ADHD pathophysiology. Future research may clarify how ADHD subtype and psychiatric comorbidities affect diffusion measures. PMID:18841089

  4. Microstructural Abnormalities in Language and Limbic Pathways in Orphanage-reared Children: A Diffusion Tensor Imaging Study

    PubMed Central

    Kumar, Ajay; Behen, Michael E.; Singsoonsud, Piti; Veenstra, Amy L.; Wolfe-Christensen, Cortney; Helder, Emily; Chugani, Harry T.

    2013-01-01

    This study utilized diffusion tensor imaging fiber tractography to examine the miscrostructural integrity of limbic and paralimbic white matter tracts in thirty-six children (Mean age=124 months) with histories of early deprivation, raised from birth in orphanages and subsequently adopted into the United States, compared to 16 age-matched typically developing children. We found increased mean diffusivity bilaterally in the arcuate fasciculus, and increased mean diffusivity and reduced fractional anisotropy bilaterally in the uncinate fasciculus and cingulum in children with early deprivation. Microstructural integrity of the left arcuate fasciculus and right cingulum was related to language and behavioral functioning, respectively. White matter abnormalities were also associated with length of deprivation and time in the adoptive home. Our findings suggest that white matter pathways, connecting limbic and paralimbic brain regions is abnormal in children with histories of early deprivation; with some pathways appearing more susceptible to early deprivation than others. PMID:23358628

  5. Microstructural abnormalities in language and limbic pathways in orphanage-reared children: a diffusion tensor imaging study.

    PubMed

    Kumar, Ajay; Behen, Michael E; Singsoonsud, Piti; Veenstra, Amy L; Wolfe-Christensen, Cortney; Helder, Emily; Chugani, Harry T

    2014-03-01

    This study utilized diffusion tensor imaging fiber tractography to examine the miscrostructural integrity of limbic and paralimbic white matter tracts in 36 children (age M = 124 months) with histories of early deprivation, raised from birth in orphanages and subsequently adopted into the United States, compared to 16 age-matched typically developing children. We found increased mean diffusivity bilaterally in the arcuate fasciculus and increased mean diffusivity and reduced fractional anisotropy bilaterally in the uncinate fasciculus and cingulum in children with early deprivation. Microstructural integrity of the left arcuate fasciculus and right cingulum was related to language and behavioral functioning, respectively. White matter abnormalities were also associated with length of deprivation and time in the adoptive home. Our findings suggest that white matter pathways, connecting limbic and paralimbic brain regions is abnormal in children with histories of early deprivation, with some pathways appearing more susceptible to early deprivation than others. PMID:23358628

  6. A multimodal mapping study of conduction aphasia with impaired repetition and spared reading aloud.

    PubMed

    Tomasino, Barbara; Marin, Dario; Maieron, Marta; D'Agostini, Serena; Medeossi, Irene; Fabbro, Franco; Skrap, Miran; Luzzatti, Claudio

    2015-04-01

    The present study explores the functional neuroanatomy of the phonological production system in an Italian aphasic patient (SP) who developed conduction aphasia of the reproduction type following brain surgery. SP presented with two peculiar features: (1) his lesion was localized in the superior temporal gyrus, just posterior to the primary auditory cortex and anterior/inferior to and neighboring the Sylvian parietal temporal (Spt) area, and (2) he presented with severely impaired repetition and spelling from dictation of words and pseudowords but spared reading-aloud of words and pseudowords. Structural, functional, fiber tracking and intraoperative findings were combined to analyze SP's pattern of performance within a widely used sensorimotor control scheme of speech production. We found a dissociation between an interrupted sector of the arcuate fasciculus terminating in STG, known to be involved in phonological processing, and a part of the arcuate fasciculus terminating in MTG, which is held to be involved in lexical-semantic processing. We argue that this phonological deficit should be interpreted as a disorder of the feedback system, in particular of the auditory and somatosensory target maps, which are assumed to be located along the Spt area. In patient SP, the spared part of the left arcuate fasciculus originating in MTG may support an unimpaired reading performance, while the damaged part of the left arcuate fasciculus originating in STG may be responsible for his impaired repetition and spelling from dictation. PMID:25701795

  7. Paraphasias in Multilingual Conduction Aphasia: A Single Case Study

    ERIC Educational Resources Information Center

    Hegde, Medha; Bhat, Sapna

    2007-01-01

    Conduction aphasia is a type of fluent aphasia, which is caused due to the damage to the supramarginal gyrus and arcuate fasciculus resulting in repetition disturbance. It has been speculated that linguistic system in bilingual aphasics can breakdown in different ways across languages. There is a lack of detailed linguistic studies in specific…

  8. Investigating the contribution of ventral-lexical and dorsal-sublexical pathways during reading in bilinguals

    PubMed Central

    Bakhtiari, Reyhaneh; Boliek, Carol; Cummine, Jacqueline

    2014-01-01

    Several studies suggest the existence of ventral-lexical and dorsal-sublexical systems for reading. The relative contribution of these pathways can be manipulated by stimulus type and task demands. However, little is known about how bilinguals use these systems to read in their second language. In this study diffusion tensor imaging (DTI) was used to investigate the relationship between white matter (WM) integrity and reaction time in a group of 12 Chinese–English bilingual and 11 age-matched English monolingual adults. Considering a dual-route model of reading, the following four tracts were isolated in both the left and right hemispheres using a tractography measurement approach. Ventral tracts included the uncinate fasciculus (UF) and the inferior longitudinal fasciculus (ILF). The dorsal tracts of interest were the arcuate fasciculus (AF) and the superior longitudinal fasciculus (SLF). A significant correlation between the reaction time in a reading task and the mean diffusivity (MD) value was observed in the right UF in both bilingual and monolingual groups. Moreover, in the bilingual group we observed significantly more positive relationships between reaction time and MD in the right AF, and bilaterally in the SLF. We concluded that the relative contribution of the dorsal system for reading is greater in bilinguals than monolinguals. Further, these findings implicate a role of the right hemisphere in reading. PMID:25071533

  9. A Tractography Study in Dyslexia: Neuroanatomic Correlates of Orthographic, Phonological and Speech Processing

    ERIC Educational Resources Information Center

    Vandermosten, Maaike; Boets, Bart; Poelmans, Hanne; Sunaert, Stefan; Wouters, Jan; Ghesquiere, Pol

    2012-01-01

    Diffusion tensor imaging tractography is a structural magnetic resonance imaging technique allowing reconstruction and assessment of the integrity of three dimensional white matter tracts, as indexed by their fractional anisotropy. It is assumed that the left arcuate fasciculus plays a crucial role for reading development, as it connects two…

  10. Progressive White Matter Microstructure Damage in Male Chronic Heroin Dependent Individuals: A DTI and TBSS Study

    PubMed Central

    Su, Huanhuan; Lv, Xiaofei; Zhang, Xuelin; Tian, Junzhang; Zhuo, Fuzhen

    2013-01-01

    Background To investigate the WM microstructure deficits in heroin dependent individuals (HDIs) with different length of heroin dependence, and to investigate whether these WM deficits can be related to the duration of heroin use and to decision-making deficits in HDIs. Methodology/Principal Findings Thirty-six HDIs [including eighteen sHDIs (duration of heroin dependent is less than 10 years) and eighteen lHDIs (duration of dependent is between 10?20 years)] and sixteen healthy controls participated in this study. Whole brain voxel-wise analysis of fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (Da) and radial diffusivity (Dr) were performed by tract-based spatial statistics (TBSS) to localize abnormal WM regions among groups. TBSS demonstrated that sHDIs had significantly lower FA than controls in right orbito-frontal WM, bilateral temporal WM and right parietal WM. The lHDIs had significantly lower FA throughout the brain compared with the controls and sHDIs. The lHDIs had significantly lower Da than controls in bilateral inferior frontaloccipital fasciculus, bilateral splenium of corpus callosum, left inferior longitudinal fasciculus, and had significantly higher Dr than controls in bilateral uncinatus fasciculus, bilateral inferior frontaloccipital fasciculus and bilateral cortical spinal fasciculus. Volume-of-interest (VOI) analyses detect the changes of diffusivity indices in the regions with FA abnormalities revealed by control vs sHDIs. In most VOIs, FA reductions were caused by the increase in Dr as well as the decrease in Da. Correlation analysis was used to assess the relationship between FA and behavioral measures in HDIs and controls available. Significantly positively correlations were found between the FA values in the right orbital-frontal WM, right parietal WM and IGT performance. Conclusions The extent and severity of WM integrity deficits in HDIs was associated with the length of heroin dependent. Furthermore, abnormal WM microstructure may correlate with decision-making impairments in HDIs. PMID:23650554

  11. Tracking the Roots of Reading Ability: White Matter Volume and Integrity Correlate with Phonological Awareness in Prereading and Early-Reading Kindergarten Children

    PubMed Central

    Osher, David E.; Beach, Sara D.; Cyr, Abigail B.; Ozernov-Palchik, Ola; Yendiki, Anastasia; Fischl, Bruce; Gaab, Nadine; Gabrieli, John D.E.

    2013-01-01

    Developmental dyslexia, an unexplained difficulty in learning to read, has been associated with alterations in white matter organization as measured by diffusion-weighted imaging. It is unknown, however, whether these differences in structural connectivity are related to the cause of dyslexia or if they are consequences of reading difficulty (e.g., less reading experience or compensatory brain organization). Here, in 40 kindergartners who had received little or no reading instruction, we examined the relation between behavioral predictors of dyslexia and white matter organization in left arcuate fasciculus, inferior longitudinal fasciculus, and the parietal portion of the superior longitudinal fasciculus using probabilistic tractography. Higher composite phonological awareness scores were significantly and positively correlated with the volume of the arcuate fasciculus, but not with other tracts. Two other behavioral predictors of dyslexia, rapid naming and letter knowledge, did not correlate with volumes or diffusion values in these tracts. The volume and fractional anisotropy of the left arcuate showed a particularly strong positive correlation with a phoneme blending test. Whole-brain regressions of behavioral scores with diffusion measures confirmed the unique relation between phonological awareness and the left arcuate. These findings indicate that the left arcuate fasciculus, which connects anterior and posterior language regions of the human brain and which has been previously associated with reading ability in older individuals, is already smaller and has less integrity in kindergartners who are at risk for dyslexia because of poor phonological awareness. These findings suggest a structural basis of behavioral risk for dyslexia that predates reading instruction. PMID:23946384

  12. Atomic-level characterization of transport cycle thermodynamics in the glycerol-3-phosphate:phosphate antiporter.

    PubMed

    Moradi, Mahmoud; Enkavi, Giray; Tajkhorshid, Emad

    2015-01-01

    Membrane transporters actively translocate their substrate by undergoing large-scale structural transitions between inward- (IF) and outward-facing (OF) states ('alternating-access' mechanism). Despite extensive structural studies, atomic-level mechanistic details of such structural transitions, and as importantly, their coupling to chemical events supplying the energy, remain amongst the most elusive aspects of the function of these proteins. Here we present a quantitative, atomic-level description of the functional thermodynamic cycle for the glycerol-3-phosphate:phosphate antiporter GlpT by using a novel approach in reconstructing the free energy landscape governing the IF?OF transition along a cyclic transition pathway involving both apo and substrate-bound states. Our results provide a fully atomic description of the complete transport process, offering a structural model for the alternating-access mechanism and substantiating the close coupling between global structural transitions and local chemical events. PMID:26417850

  13. Atomic-level characterization of transport cycle thermodynamics in the glycerol-3-phosphate:phosphate antiporter

    NASA Astrophysics Data System (ADS)

    Moradi, Mahmoud; Enkavi, Giray; Tajkhorshid, Emad

    2015-09-01

    Membrane transporters actively translocate their substrate by undergoing large-scale structural transitions between inward- (IF) and outward-facing (OF) states (`alternating-access' mechanism). Despite extensive structural studies, atomic-level mechanistic details of such structural transitions, and as importantly, their coupling to chemical events supplying the energy, remain amongst the most elusive aspects of the function of these proteins. Here we present a quantitative, atomic-level description of the functional thermodynamic cycle for the glycerol-3-phosphate:phosphate antiporter GlpT by using a novel approach in reconstructing the free energy landscape governing the IF<-->OF transition along a cyclic transition pathway involving both apo and substrate-bound states. Our results provide a fully atomic description of the complete transport process, offering a structural model for the alternating-access mechanism and substantiating the close coupling between global structural transitions and local chemical events.

  14. Evaluation of the Degradation of the Selected Projectile, Commissural and Association White Matter Tracts Within Normal Appearing White Matter in Patients with Multiple Sclerosis Using Diffusion Tensor MR Imaging – a Preliminary Study

    PubMed Central

    Banaszek, Anna; Bladowska, Joanna; Pokryszko-Dragan, Anna; Podemski, Ryszard; Sąsiadek, Marek J.

    2015-01-01

    Summary Backround The aim of the study was to assess the impairment of the selected white matter tracts within normal appearing white matter (NAWM) in multiple sclerosis (MS) patients using diffusion tensor imaging (DTI). Material/Methods Thirty-six patients (mean age 33.4 yrs) with clinically definite, relapsing-remitting MS and mild disability (EDSS – Expanded Disability Status Scale 1–3.5) and 16 control subjects (mean age 34.4 yrs) were enrolled in the study. DTI examinations were performed on a 1.5T MR scanner. Fractional anisotropy (FA) and apparent diffusion coefficient (ADC) values were obtained with a small ROI method in several white matter tracts within NAWM including: the middle cerebellar peduncles (MCP), the inferior longitudinal fasciculi (ILF), inferior frontooccipital fasciculi (IFOF), genu (GCC) and splenium of the corpus callosum (SCC), posterior limbs of the internal capsules (PLIC), superior longitudinal fasciculi (SLF) and posterior cingula (CG). There were no demyelinative lesions within the ROIs in any of the patients. Results A significant decrease in FA was found in MS patients in both the ILFs and IFOFs (p<0.001) and in the left MCP and right SLF (p<0.05), compared to the normal subjects. There were no significant differences in FA values in the remaining evaluated ROIs, between MS patients and the control group. A significant increase in ADC (p<0.05) was found only in the right PLIC and the right SLF in MS subjects, compared to the control group. Conclusions The FA values could be a noninvasive neuroimaging biomarker for assessing the microstructural changes within NAWM tracts in MS patients. PMID:26516389

  15. Structural changes in white matter are uniquely related to children’s reading development

    PubMed Central

    Myers, Chelsea A.; Vandermosten, Maaike; Farris, Emily A.; Hancock, Roeland; Gimenez, Paul; Black, Jessica M.; Casto, Brandi; Drahos, Miroslav; Tumber, Mandeep; Hendren, Robert L.; Hulme, Charles; Hoeft, Fumiko

    2014-01-01

    This study examined whether variations in brain development between kindergarten and Grade 3 predicted individual differences in reading ability at the latter time point. Structural MRI measurements indicated that increases in volume of two left temporo-parietal white matter clusters are unique predictors of reading outcome at Grade 3. Using diffusion MRI, the larger of these two clusters was identified as a location where fibers of the long segment of arcuate fasciculus and superior corona radiata intersect, and the smaller cluster as the posterior arcuate fasciculus. Bias-free regression analyses using regions-of-interest from prior literature revealed white matter volume changes in temporo-parietal white matter, together with preliteracy measures, predicted 56% of the variance in reading outcomes. Our findings demonstrate the important contribution of developmental differences in areas of left dorsal white matter, often implicated in phonological processing, as a sensitive early biomarker for later reading abilities, and by extension, reading difficulties. PMID:25212581

  16. Anatomy is strategy: Skilled reading differences associated with structural connectivity differences in the reading network

    PubMed Central

    Graves, William W.; Binder, Jeffrey R.; Desai, Rutvik H.; Humphries, Colin; Stengel, Benjamin C.; Seidenberg, Mark S.

    2014-01-01

    Are there multiple ways to be a skilled reader? To address this longstanding, unresolved question, we hypothesized that individual variability in using semantic information in reading aloud would be associated with neuroanatomical variation in pathways linking semantics and phonology. Left-hemisphere regions of interest for diffusion tensor imaging analysis were defined based on fMRI results, including two regions linked with semantic processing – angular gyrus (AG) and inferior temporal sulcus (ITS) – and two linked with phonological processing – posterior superior temporal gyrus (pSTG) and posterior middle temporal gyrus (pMTG). Effects of imageability (a semantic measure) on response times varied widely among individuals and covaried with the volume of pathways through the ITS and pMTG, and through AG and pSTG, partially overlapping the inferior longitudinal fasciculus and the posterior branch of the arcuate fasciculus. These results suggest strategy differences among skilled readers associated with structural variation in the neural reading network. PMID:24735993

  17. Continuity, Divergence, and the Evolution of Brain Language Pathways

    PubMed Central

    Rilling, James K.; Glasser, Matthew F.; Jbabdi, Saad; Andersson, Jesper; Preuss, Todd M.

    2011-01-01

    Recently, the assumption of evolutionary continuity between humans and non-human primates has been used to bolster the hypothesis that human language is mediated especially by the ventral extreme capsule pathway that mediates auditory object recognition in macaques. Here, we argue for the importance of evolutionary divergence in understanding brain language evolution. We present new comparative data reinforcing our previous conclusion that the dorsal arcuate fasciculus pathway was more significantly modified than the ventral extreme capsule pathway in human evolution. Twenty-six adult human and twenty-six adult chimpanzees were imaged with diffusion-weighted MRI and probabilistic tractography was used to track and compare the dorsal and ventral language pathways. Based on these and other data, we argue that the arcuate fasciculus is likely to be the pathway most essential for higher-order aspects of human language such as syntax and lexical–semantics. PMID:22319495

  18. [Tourette syndrome and reading disorder in a boy with left parietofrontal tract disruption].

    PubMed

    Martín Fernández-Mayoralas, D; Fernández-Jaén, A; Gómez Herrera, J J; Jiménez de la Peña, M

    2014-01-01

    We present the case of a nine-year-old boy with Tourette syndrome and reading disorder with a history of a severe infectious process in the late neonatal period. Brain MRI showed a left parietal malacotic cavity and diffusion tensor imaging and tractography showed a striking disruption of the white matter bundle that joins the left parietal region with the ipsilateral frontal region with involvement of the left superior longitudinal fasciculus and of the left arcuate fasciculus. Although Tourette syndrome and reading disorder are fundamentally hereditary neuropsychiatric disorders, they can also occur secondary to cerebral alterations like those existing in this boy. The introduction of modern neuroimaging techniques in patients with neuropsychiatric disorders (or the risk of developing them) can be very useful in the diagnosis and prognosis in the future. PMID:22019420

  19. An 8-month Exercise Intervention Alters Fronto-temporal White Matter Integrity in Overweight Children

    PubMed Central

    Schaeffer, David J.; Krafft, Cynthia E.; Schwarz, Nicolette F.; Chi, Lingxi; Rodrigue, Amanda L.; Pierce, Jordan E.; Allison, Jerry D.; Yanasak, Nathan E.; Liu, Tianming; Davis, Catherine L.; McDowell, Jennifer E.

    2014-01-01

    In childhood, excess adiposity and low fitness are linked to poor academic performance, lower cognitive function, and differences in brain structure. Identifying ways to mitigate obesity-related alterations is of current clinical importance. This study examined the effects of an 8-month exercise intervention on the uncinate fasciculus, a white matter fiber tract connecting frontal and temporal lobes. Participants consisted of 18 unfit, overweight 8–11 year-old children (94% Black) who were randomly assigned to either an aerobic exercise (n=10) or a sedentary control group (n=8). Before and after the intervention, all subjects participated in a diffusion tensor MRI scan. Tractography was conducted to isolate the uncinate fasciculus. The exercise group showed improved white matter integrity as compared to the control group. These findings are consistent with an emerging literature suggesting beneficial effects of exercise on white matter integrity. PMID:24797659

  20. Contributions of bilateral white matter to chronic aphasia symptoms as assessed by diffusion tensor MRI

    PubMed Central

    Geva, Sharon; Correia, Marta M.; Warburton, Elizabeth A.

    2015-01-01

    Language reorganisation following stroke has been studied widely. However, while studies of brain activation and grey matter examined both hemispheres, studies of white matter changes have mostly focused on the left hemisphere. Here we examined the relationship between bilateral hemispheric white matter and aphasia symptoms. 15 chronic stroke patients with aphasia and 18 healthy adults were studied using Diffusion Weighted Imaging data. By applying histogram analysis, Tract-Based Spatial Statistics, tractography and lesion-tract overlap methods, it was found that damage to the left hemisphere in general, and to the arcuate fasciculus in particular, correlated with impairments on word repetition, object naming, sentence comprehension and homophone and rhyme judgement. However, no such relationship was found in the right hemisphere. It is suggested that while some language function in aphasia can be explained by damage to the left arcuate fasciculus, it cannot be explained by looking at the contra-lesional tract. PMID:26401977

  1. A novel frontal pathway underlies verbal fluency in primary progressive aphasia.

    PubMed

    Catani, Marco; Mesulam, Marsel M; Jakobsen, Estrid; Malik, Farah; Martersteck, Adam; Wieneke, Christina; Thompson, Cynthia K; Thiebaut de Schotten, Michel; Dell'Acqua, Flavio; Weintraub, Sandra; Rogalski, Emily

    2013-08-01

    The frontal aslant tract is a direct pathway connecting Broca's region with the anterior cingulate and pre-supplementary motor area. This tract is left lateralized in right-handed subjects, suggesting a possible role in language. However, there are no previous studies that have reported an involvement of this tract in language disorders. In this study we used diffusion tractography to define the anatomy of the frontal aslant tract in relation to verbal fluency and grammar impairment in primary progressive aphasia. Thirty-five patients with primary progressive aphasia and 29 control subjects were recruited. Tractography was used to obtain indirect indices of microstructural organization of the frontal aslant tract. In addition, tractography analysis of the uncinate fasciculus, a tract associated with semantic processing deficits, was performed. Damage to the frontal aslant tract correlated with performance in verbal fluency as assessed by the Cinderella story test. Conversely, damage to the uncinate fasciculus correlated with deficits in semantic processing as assessed by the Peabody Picture Vocabulary Test. Neither tract correlated with grammatical or repetition deficits. Significant group differences were found in the frontal aslant tract of patients with the non-fluent/agrammatic variant and in the uncinate fasciculus of patients with the semantic variant. These findings indicate that degeneration of the frontal aslant tract underlies verbal fluency deficits in primary progressive aphasia and further confirm the role of the uncinate fasciculus in semantic processing. The lack of correlation between damage to the frontal aslant tract and grammar deficits suggests that verbal fluency and grammar processing rely on distinct anatomical networks. PMID:23820597

  2. A novel frontal pathway underlies verbal fluency in primary progressive aphasia

    PubMed Central

    Mesulam, Marsel M.; Jakobsen, Estrid; Malik, Farah; Martersteck, Adam; Wieneke, Christina; Thompson, Cynthia K.; Thiebaut de Schotten, Michel; Dell’Acqua, Flavio; Weintraub, Sandra; Rogalski, Emily

    2013-01-01

    The frontal aslant tract is a direct pathway connecting Broca’s region with the anterior cingulate and pre-supplementary motor area. This tract is left lateralized in right-handed subjects, suggesting a possible role in language. However, there are no previous studies that have reported an involvement of this tract in language disorders. In this study we used diffusion tractography to define the anatomy of the frontal aslant tract in relation to verbal fluency and grammar impairment in primary progressive aphasia. Thirty-five patients with primary progressive aphasia and 29 control subjects were recruited. Tractography was used to obtain indirect indices of microstructural organization of the frontal aslant tract. In addition, tractography analysis of the uncinate fasciculus, a tract associated with semantic processing deficits, was performed. Damage to the frontal aslant tract correlated with performance in verbal fluency as assessed by the Cinderella story test. Conversely, damage to the uncinate fasciculus correlated with deficits in semantic processing as assessed by the Peabody Picture Vocabulary Test. Neither tract correlated with grammatical or repetition deficits. Significant group differences were found in the frontal aslant tract of patients with the non-fluent/agrammatic variant and in the uncinate fasciculus of patients with the semantic variant. These findings indicate that degeneration of the frontal aslant tract underlies verbal fluency deficits in primary progressive aphasia and further confirm the role of the uncinate fasciculus in semantic processing. The lack of correlation between damage to the frontal aslant tract and grammar deficits suggests that verbal fluency and grammar processing rely on distinct anatomical networks. PMID:23820597

  3. Maturation Along White Matter Tracts in Human Brain Using a Diffusion Tensor Surface Model Tract-Specific Analysis

    PubMed Central

    Chen, Zhang; Zhang, Hui; Yushkevich, Paul A.; Liu, Min; Beaulieu, Christian

    2016-01-01

    Previous diffusion tensor imaging tractography studies have demonstrated exponential patterns of developmental changes for diffusion parameters such as fractional anisotropy (FA) and mean diffusivity (MD) averaged over all voxels in major white matter (WM) tracts of the human brain. However, this assumes that the entire tract is changing in unison, which may not be the case. In this study, a surface model based tract-specific analysis was applied to a cross-sectional cohort of 178 healthy subjects (83 males/95 females) aged from 6 to 30 years to spatially characterize the age-related changes of FA and MD along the trajectory of seven major WM tracts – corpus callosum (CC) and six bilateral tracts. There were unique patterns of regions that showed different exponential and linear rates of increasing FA or decreasing MD and age at which FA or MD levels off along each tract. Faster change rate of FA was observed in genu of CC and frontal-parietal part of superior longitudinal fasciculus (SLF). Inferior corticospinal tract (CST), posterior regions of association tracts such as inferior longitudinal fasciculus, inferior frontal occipital fasciculus and uncinate fasciculus also displayed earlier changing patterns for FA. MD decreases with age also exhibited this posterior-to-anterior WM maturation pattern for most tracts in females. Both males and females displayed similar FA/MD patterns of change with age along most large tracts; however, males had overall reached the FA maxima or MD minima later compared with females in most tracts with the greater differences occurring in the CST and frontal-parietal part of SLF for MD. Therefore, brain WM development has spatially varying trajectories along tracts that depend on sex and the tract. PMID:26909027

  4. [Language mapping with direct electrical stimulation].

    PubMed

    Suzuki, Kyoko

    2012-09-01

    Language mapping with electrical stimulation in patients with lesions close to the language area aids surgery by identifying the language area in each individual. This method is quite important in a clinical setting, and is the most reliable for preventing persistent language deficits after resection. Furthermore, language mapping with electrical stimulation has revealed that the functional organization of the language area is more complex than previously suggested by functional MRI and other methods. The language-related sites where electrical stimulation induced abnormality during language tasks were spatially distinct and surprisingly varied amona patients. In addition, electrical stimulation revealed a mosaic of language function, in which sites even 5-10 mm apart were functionally distinct. Cortical sites specifically related to a language function e.g., repetition, were surrounded by sites related to another language function but not to repetition. These findings suggested that the "language area" is not spatially homogeneous over centimeters of the cortex, but consists of functional sub-regions of the cortex. Findings obtained using intraoperative electrical stimulation of the subcortical white matter have supported the dual language pathways-the dorsal and ventral pathways. Electrical stimulation of the arcuate fasciculus induced phonological paraphasia and that of the inferior occipitofrontal fasciculus induced semantic paraphasia. However, no language deficits were induced by stimulation of the inferior longitudinal fasciculus, thereby indicating the indirect role of this bundle in language function. Our current models of human language organization can be modified on the basis of language mapping with electrical stimulation. PMID:22941837

  5. Abnormal auditory and language pathways in children with 16p11.2 deletion

    PubMed Central

    Berman, Jeffrey I.; Chudnovskaya, Darina; Blaskey, Lisa; Kuschner, Emily; Mukherjee, Pratik; Buckner, Randall; Nagarajan, Srikantan; Chung, Wendy K.; Spiro, John E.; Sherr, Elliott H.; Roberts, Timothy P.L.

    2015-01-01

    Copy number variations at chromosome 16p11.2 contribute to neurodevelopmental disorders, including autism spectrum disorder (ASD). This study seeks to improve our understanding of the biological basis of behavioral phenotypes common in ASD, in particular the prominent and prevalent disruption of spoken language seen in children with the 16p11.2 BP4–BP5 deletion. We examined the auditory and language white matter pathways with diffusion MRI in a cohort of 36 pediatric deletion carriers and 45 age-matched controls. Diffusion MR tractography of the auditory radiations and the arcuate fasciculus was performed to generate tract specific measures of white matter microstructure. In both tracts, deletion carriers exhibited significantly higher diffusivity than that of controls. Cross-sectional diffusion parameters in these tracts changed with age with no group difference in the rate of maturation. Within deletion carriers, the left-hemisphere arcuate fasciculus mean and radial diffusivities were significantly negatively correlated with clinical language ability, but not non-verbal cognitive ability. Diffusion metrics in the right-hemisphere arcuate fasciculus were not predictive of language ability. These results provide insight into the link between the 16p11.2 deletion, abnormal auditory and language pathway structures, and the specific behavioral deficits that may contribute to neurodevelopmental disorders such as ASD. PMID:26413471

  6. Tract-Specific Correlates of Neuropsychological Deficits in Patients with Subcortical Vascular Cognitive Impairment.

    PubMed

    Jung, Na-Yeon; Han, Cheol E; Kim, Hee Jin; Yoo, Sang Wook; Kim, Hee-Jong; Kim, Eun-Joo; Na, Duk L; Lockhart, Samuel N; Jagust, William J; Seong, Joon-Kyung; Seo, Sang Won

    2016-01-19

    The white matter tract-specific correlates of neuropsychological deficits are not fully established in patients with subcortical vascular cognitive impairment (SVCI), where white matter tract damage may be a critical factor in cognitive impairment. The purpose of this study is to investigate the tract-specific correlates of neuropsychological deficits in SVCI patients using tract-specific statistical analysis (TSSA). We prospectively recruited 114 SVCI patients, and 55 age-, gender-, and education-matched individuals with normal cognition (NC). All participants underwent diffusion weighted imaging and neuropsychological testing. We classified tractography results into fourteen major fiber tracts and analyzed group comparison and correlation with cognitive impairments. Relative to NC subjects, SVCI patients showed decreased fractional anisotropy values in bilateral anterior-thalamic radiation, cingulum, superior-longitudinal fasciculus, uncinate fasciculus, corticospinal tract, and left inferior-longitudinal fasciculus. Focal disruptions in specific tracts were associated with specific cognitive impairments. Our findings suggest that disconnection of specific white matter tracts, especially those neighboring and providing connections between gray matter regions important to certain cognitive functions, may contribute to specific cognitive impairments in SVCI. PMID:26836179

  7. Regional White Matter Damage Predicts Speech Fluency in Chronic Post-Stroke Aphasia

    PubMed Central

    Basilakos, Alexandra; Fillmore, Paul T.; Rorden, Chris; Guo, Dazhou; Bonilha, Leonardo; Fridriksson, Julius

    2014-01-01

    Recently, two different white matter regions that support speech fluency have been identified: the aslant tract and the anterior segment of the arcuate fasciculus (ASAF). The role of the ASAF was demonstrated in patients with post-stroke aphasia, while the role of the aslant tract shown in primary progressive aphasia. Regional white matter integrity appears to be crucial for speech production; however, the degree that each region exerts an independent influence on speech fluency is unclear. Furthermore, it is not yet defined if damage to both white matter regions influences speech in the context of the same neural mechanism (stroke-induced aphasia). This study assessed the relationship between speech fluency and quantitative integrity of the aslant region and the ASAF. It also explored the relationship between speech fluency and other white matter regions underlying classic cortical language areas such as the uncinate fasciculus and the inferior longitudinal fasciculus (ILF). Damage to these regions, except the ILF, was associated with speech fluency, suggesting synergistic association of these regions with speech fluency in post-stroke aphasia. These observations support the theory that speech fluency requires the complex, orchestrated activity between a network of pre-motor, secondary, and tertiary associative cortices, supported in turn by regional white matter integrity. PMID:25368572

  8. Distinguishing the effect of lesion load from tract disconnection in the arcuate and uncinate fasciculi.

    PubMed

    Hope, Thomas M H; Seghier, Mohamed L; Prejawa, Susan; Leff, Alex P; Price, Cathy J

    2016-01-15

    Brain imaging studies of functional outcomes after white matter damage have quantified the severity of white matter damage in different ways. Here we compared how the outcome of such studies depends on two different types of measurements: the proportion of the target tract that has been destroyed ('lesion load') and tract disconnection. We demonstrate that conclusions from analyses based on two examples of these measures diverge and that conclusions based solely on lesion load may be misleading. First, we reproduce a recent lesion-load-only analysis which suggests that damage to the arcuate fasciculus, and not to the uncinate fasciculus, is significantly associated with deficits in fluency and naming skills. Next, we repeat the analysis after replacing the measures of lesion load with measures of tract disconnection for both tracts, and observe significant associations between both tracts and both language skills: i.e. the change increases the apparent relevance of the uncinate fasciculus to fluency and naming skills. Finally we show that, in this dataset, disconnection data explains significant variance in both language skills that is not accounted for by lesion load or volume, but lesion load data explains no unique variance in those skills, once disconnection and lesion volume are taken into account. PMID:26388553

  9. Outcomes of Diffusion Tensor Tractography-Integrated Stereotactic Radiosurgery

    SciTech Connect

    Koga, Tomoyuki; Maruyama, Keisuke; Kamada, Kyousuke; Ota, Takahiro; Shin, Masahiro; Itoh, Daisuke; Kunii, Naoto; Ino, Kenji; Terahara, Atsuro; Aoki, Shigeki; Masutani, Yoshitaka; Saito, Nobuhito

    2012-02-01

    Purpose: To analyze the effect of use of tractography of the critical brain white matter fibers created from diffusion tensor magnetic resonance imaging on reduction of morbidity associated with radiosurgery. Methods and Materials: Tractography of the pyramidal tract has been integrated since February 2004 if lesions are adjacent to it, the optic radiation since May 2006, and the arcuate fasciculus since October 2007. By visually confirming the precise location of these fibers, the dose to these fiber tracts was optimized. One hundred forty-four consecutive patients with cerebral arteriovenous malformations who underwent radiosurgery with this technique between February 2004 and December 2009 were analyzed. Results: Tractography was prospectively integrated in 71 of 155 treatments for 144 patients. The pyramidal tract was visualized in 45, the optic radiation in 22, and the arcuate fasciculus in 13 (two tracts in 9). During the follow-up period of 3 to 72 months (median, 23 months) after the procedure, 1 patient showed permanent worsening of pre-existing dysesthesia, and another patient exhibited mild transient hemiparesis 12 months later but fully recovered after oral administration of corticosteroid agents. Two patients had transient speech disturbance before starting integration of the arcuate fasciculus tractography, but no patient thereafter. Conclusion: Integrating tractography helped prevent morbidity of radiosurgery in patients with brain arteriovenous malformations.

  10. White matter disruption at the prodromal stage of Alzheimer's disease: relationships with hippocampal atrophy and episodic memory performance.

    PubMed

    Rémy, Florence; Vayssière, Nathalie; Saint-Aubert, Laure; Barbeau, Emmanuel; Pariente, Jérémie

    2015-01-01

    White matter tract alterations have been consistently described in Alzheimer's disease (AD). In particular, limbic fronto-temporal connections, which are critical to episodic memory function, may degenerate early in the course of the disease. However the relation between white matter tract degeneration, hippocampal atrophy and episodic memory impairment at the earliest stages of AD is still unclear. In this magnetic resonance imaging study, white matter integrity and hippocampal volumes were evaluated in patients with amnestic mild cognitive impairment due to AD (Albert et al., 2011) (n = 22) and healthy controls (n = 15). Performance in various episodic memory tasks was also evaluated in each participant. Relative to controls, patients showed a significant reduction of white matter fractional anisotropy (FA) and increase of radial diffusivity (RD) in the bilateral uncinate fasciculus, parahippocampal cingulum and fornix. Within the patient group, significant intra-hemispheric correlations were notably found between hippocampal grey matter volume and FA in the uncinate fasciculus, suggesting a relationship between atrophy and disconnection of the hippocampus. Moreover, episodic recognition scores were related with uncinate fasciculus FA across patients. These results indicate that fronto-hippocampal connectivity is reduced from the earliest pre-demential stages of AD. Disruption of fronto-hippocampal connections may occur progressively, in parallel with hippocampal atrophy, and may specifically contribute to early initial impairment in episodic memory. PMID:25685715

  11. Changes to memory structures in children treated for posterior fossa tumors.

    PubMed

    Riggs, Lily; Bouffet, Eric; Laughlin, Suzanne; Laperriere, Normand; Liu, Fang; Skocic, Jovanka; Scantlebury, Nadia; Wang, Frank; Schoenhoff, Nicholas J; Strother, Douglas; Hukin, Juliette; Fryer, Christopher; McConnell, Dina; Mabbott, Donald J

    2014-02-01

    Children treated for medulloblastoma (MB) exhibit long-term impairments in declarative memory, but the pathophysiology underlying this is unclear. Previous studies report declines in global white matter volume, but have failed to link this to declines in memory performance. We examined the effects of treatment on measures of global brain structure (i.e., total white and gray matter volume) and specific memory structures (i.e., hippocampus and uncinate fasciculus). We used volumetric MRI and diffusion tensor imaging in pediatric survivors of MB and one survivor of astrocytoma treated with cranial-spinal radiation (n = 20), and healthy controls (n = 13). Compared to controls, the survivor group exhibited reduced white matter volume, damage to the uncinate fasciculus, and a smaller right hippocampus. Critically, reduced hippocampal volume was not related to differences in brain volume, suggesting that the hippocampus may be especially vulnerable to treatment effects. A subset of the survivors (n = 10) also underwent memory testing using the Children's Memory Scale (CMS). Performance on the general index of the CMS was significantly correlated with measures of hippocampal volume and uncinate fasciculus. The examination of treatment effects on specific brain regions provides a better understanding of long-term cognitive outcome in children with brain tumors, particularly medulloblastoma. PMID:24460980

  12. Distinguishing the effect of lesion load from tract disconnection in the arcuate and uncinate fasciculi

    PubMed Central

    Hope, Thomas M.H.; Seghier, Mohamed L.; Prejawa, Susan; Leff, Alex P.; Price, Cathy J.

    2016-01-01

    Brain imaging studies of functional outcomes after white matter damage have quantified the severity of white matter damage in different ways. Here we compared how the outcome of such studies depends on two different types of measurements: the proportion of the target tract that has been destroyed (‘lesion load’) and tract disconnection. We demonstrate that conclusions from analyses based on two examples of these measures diverge and that conclusions based solely on lesion load may be misleading. First, we reproduce a recent lesion-load-only analysis which suggests that damage to the arcuate fasciculus, and not to the uncinate fasciculus, is significantly associated with deficits in fluency and naming skills. Next, we repeat the analysis after replacing the measures of lesion load with measures of tract disconnection for both tracts, and observe significant associations between both tracts and both language skills: i.e. the change increases the apparent relevance of the uncinate fasciculus to fluency and naming skills. Finally we show that, in this dataset, disconnection data explains significant variance in both language skills that is not accounted for by lesion load or volume, but lesion load data explains no unique variance in those skills, once disconnection and lesion volume are taken into account. PMID:26388553

  13. The Effect of Acupuncture on the Motor Function and White Matter Microstructure in Ischemic Stroke Patients

    PubMed Central

    Li, Yongxin; Wang, Ya; Zhang, Heye; Wu, Ping; Huang, Wenhua

    2015-01-01

    Evidence shows that ischemic stroke can induce brain structural reorganization. Acupuncture is advised as an adjunct to mainstream rehabilitation after stroke. However, the effectiveness of acupuncture is inconsistent among previous studies. Fourteen ischemic patients were collected and divided into two groups: conventional treatment group (CG) and acupuncture treatment group (AG). The results of a Fugl-Meyer Assessment (FMA) and diffusion tensor imaging were collected before and after treatment. The AG exhibited a higher improvement in FMA than the CG. Repeated measures analysis of variance on diffusion data only found a significant main effect for scanning time point in all diffusion indices. In each group, a postpair t-test revealed that diffusion indices values were changed significantly after treatment intervention in the body of the corpus callosum and bilateral corticospinal tracts, the inferior longitudinal fasciculus, the inferior frontooccipital fasciculus, the superior longitudinal fasciculus, the forceps minor, the cingulum gyrus, and the thalamic radiation. However, there was no significant difference in the diffusion indices between the two groups. In conclusion, acupuncture had a better behavioral score than traditional medicine treatment. However, acupuncture did not significantly change WM in the AG compared to the CG as expected within one month after the intervention. PMID:26576189

  14. Neural plasticity after pre-linguistic injury to the arcuate and superior longitudinal fasciculi.

    PubMed

    Yeatman, Jason D; Feldman, Heidi M

    2013-01-01

    We describe the case of girl who was born prematurely and diagnosed periventricular leukomalacia, a condition characterized by severe injury to the white matter tracts primarily surrounding the ventricles. At 12 years of age, we obtained diffusion tensor imaging (DTI) data on this child as part of a research protocol. Multiple analyses of DTI data, including tractography, showed that the left and right arcuate and superior longitudinal fasciculi were missing in the child though all other major white matter tracts were present. Standardized psychometric tests at age 12 years revealed that despite early language delays, she had average scores on expressive language, sentence repetition, and reading, functions that have been hypothesized to depend on signals carried by the arcuate fasciculus. We identified intact ventral connections between the temporal and frontal lobes through the extreme capsule fiber system and uncinate fasciculus. Preserved language and reading function after serious injury to the arcuate fasciculus highlights the plasticity of the developing brain after severe white matter injury early in life. PMID:21937035

  15. Altered structural connectivity and trait anhedonia in patients with schizophrenia.

    PubMed

    Lee, Jung Suk; Han, Kiwan; Lee, Seung-Koo; Seok, Jeong-Ho; Kim, Jae-Jin

    2014-09-01

    This study tested association between anhedonia scores and white matter integrity in order to investigate the neural basis of trait anhedonia in schizophrenia. A total of 31 patients with schizophrenia and 33 healthy controls underwent diffusion weighted imaging and scoring of trait anhedonia using the Physical Anhedonia Scale. Using tract-based spatial statistics, we found that fractional anisotropy values of some white matter regions were differently correlated with Physical Anhedonia Scale scores between the two groups. The white matter regions that were more significantly correlated with trait anhedonia in patients than in controls included the left side of the cingulum, splenium of the corpus callosum, inferior longitudinal fasciculus, superior longitudinal fasciculus I and II, anterior thalamic radiation, and optic radiation. Of these regions, fractional anisotropy values in the cingulum and superior longitudinal fasciculus II were positively correlated with trait anhedonia in patients with schizophrenia. These findings suggest that alterations in structural connectivity within large-scale brain networks, including the default mode and central executive networks, may contribute to the development of trait anhedonia in patients with schizophrenia. PMID:25017826

  16. Profiles of aberrant white matter microstructure in fragile X syndrome

    PubMed Central

    Hall, Scott S.; Dougherty, Robert F.; Reiss, Allan L.

    2016-01-01

    Previous studies attempting to quantify white matter (WM) microstructure in individuals with fragile X syndrome (FXS) have produced inconsistent findings, most likely due to the various control groups employed, differing analysis methods, and failure to examine for potential motion artifact. In addition, analyses have heretofore lacked sufficient specificity to provide regional information. In this study, we used Automated Fiber-tract Quantification (AFQ) to identify specific regions of aberrant WM microstructure along WM tracts in patients with FXS that differed from controls who were matched on age, IQ and degree of autistic symptoms. Participants were 20 patients with FXS, aged 10 to 23 years, and 20 matched controls. Using Automated Fiber-tract Quantification (AFQ), we created Tract Profiles of fractional anisotropy and mean diffusivity along 18 major WM fascicles. We found that fractional anisotropy was significantly increased in the left and right inferior longitudinal fasciculus (ILF), right uncinate fasciculus, and left cingulum hippocampus in individuals with FXS compared to controls. Conversely, mean diffusivity was significantly decreased in the right ILF in patients with FXS compared to controls. Age was significantly negatively associated with MD values across both groups in 11 tracts. Taken together, these findings indicate that FXS results in abnormal WM microstructure in specific regions of the ILF and uncinate fasciculus, most likely caused by inefficient synaptic pruning as a result of decreased or absent Fragile X Mental Retardation Protein (FMRP). Longitudinal studies are needed to confirm these findings. PMID:26937381

  17. Clinical findings and white matter abnormalities seen on diffusion tensor imaging in adolescents with very low birth weight.

    PubMed

    Skranes, J; Vangberg, T R; Kulseng, S; Indredavik, M S; Evensen, K A I; Martinussen, M; Dale, A M; Haraldseth, O; Brubakk, A-M

    2007-03-01

    Very low birth weight (VLBW) children are at high risk of perinatal white matter injury, which, when subtle, may not be seen using conventional magnetic resonance imaging. The relationship between clinical findings and fractional anisotropy (FA) measurements in white matter of adolescents born prematurely with VLBW was studied in 34 subjects (age = 15 years, birth weight fasciculus. Within this group of children, visual motor and visual perceptual deficits were associated with low FA values in the external capsule, posterior part of the internal capsule and in the inferior fasciculus. Children with low IQ had low FA values in the external capsule and inferior and middle superior fasciculus. Fine motor impairment was related to low FA values in the internal and external capsule and superior fasciculus. Eight VLBW children with inattention symptoms or a diagnosis of ADHD had significantly lower FA values in several areas. Mild social deficits correlated with reduced FA values in the external capsule and superior fasciculus. We conclude that DTI was able to detect differences in FA between VLBW adolescents and controls in several white matter areas at risk of periventricular leucomalacia in VLBW newborns. Our results show that low FA values in these areas were associated with perceptual, cognitive, motor and mental health impairments. These conclusions indicate that perinatal injury of white matter tracts persist with clinical significance in adolescence. PMID:17347255

  18. Structural brain changes related to bilingualism: does immersion make a difference?

    PubMed Central

    Stein, Maria; Winkler, Carmen; Kaiser, Anelis; Dierks, Thomas

    2014-01-01

    Within the field of neuroscientific research on second language learning, considerable attention has been devoted to functional and recently also structural changes related to second language acquisition. The present literature review summarizes studies that investigated structural changes related to bilingualism. Furthermore, as recent evidence has suggested that native-like exposure to a second language (i.e., a naturalistic learning setting or immersion) considerably impacts second language learning, all findings are reflected with respect to the learning environment. Aggregating the existing evidence, we conclude that structural changes in left inferior frontal and inferior parietal regions have been observed in studies on cortical gray matter changes, while the anterior parts of the corpus callosum have been repeatedly found to reflect bilingualism in studies on white matter (WM) connectivity. Regarding the learning environment, no cortical alterations can be attributed specifically to naturalistic or classroom learning. With regard to WM changes, one might tentatively propose that changes in IFOF and SLF are possibly more prominently observed in studies investigating bilinguals with a naturalistic learning experience. However, future studies are needed to replicate and strengthen the existing evidence and to directly test the impact of naturalistic exposure on structural brain plasticity. PMID:25324816

  19. Improvement of the transmission performance in multi-IF-over-fiber mobile fronthaul by using tone-reservation technique.

    PubMed

    Sung, Minkyu; Han, Changyo; Cho, Seung-Hyun; Chung, Hwan Seok; Lee, Jong Hyun

    2015-11-16

    We demonstrate the improvement of the transmission performance based on tone-reservation technique in a multiple intermediate-frequency-over-fiber (IFoF) based mobile fronthaul. The tone-reservation technique can suppress nonlinear distortion by eliminating the high peak components of orthogonal frequency-division multiplexing (OFDM) signal. To prevent the regrowth of peak, we employ tone-reservation after multiplexing IF carriers. Furthermore, we use an out-of-band signal as the reserved tones to avoid any modification of a mobile signal. The impact of the number of IF carriers on peak-to-average power ratio (PAPR) characteristics is presented via numerical simulation. For the multi-IFoF based mobile fronthaul, we experimentally investigate the transmission performance of 36-IF carriers of the long term evolution-advanced (LTE-A) signals mapped with 64-quadrature amplitude modulation (QAM). It is clearly observed that the clipping-induced nonlinear distortion is dramatically suppressed by using tone-reservation. As a result, the transmission performance of 36-IF carriers of the LTE-A signal is improved by an error-vector-magnitude (EVM) of 4% (from 9.7% to 5.7%) after 20-km transmission. PMID:26698444

  20. Mild White Matter Changes in Un-medicated Obsessive-Compulsive Disorder Patients and Their Unaffected Siblings

    PubMed Central

    Fan, Siyan; van den Heuvel, Odile A.; Cath, Danielle C.; van der Werf, Ysbrand D.; de Wit, Stella J.; de Vries, Froukje E.; Veltman, Dick J.; Pouwels, Petra J. W.

    2016-01-01

    Objective: Obsessive-compulsive disorder (OCD) is a common neuropsychiatric disorder with moderate genetic influences and white matter abnormalities in frontal-striatal and limbic regions. Inconsistencies in reported white matter results from diffusion tensor imaging (DTI) studies can be explained, at least partly, by medication use and between-group differences in disease profile and stage. We used a family design aiming to establish whether white matter abnormalities, if present in un-medicated OCD patients, also exist in their unaffected siblings. Method: Forty-four OCD patients, un-medicated for at least the past 4 weeks, 15 of their unaffected siblings, and 37 healthy controls (HC) underwent DTI using a 3-Tesla MRI-scanner. Data analysis was done using tract-based spatial statistics (TBSS). Fractional anisotropy (FA), axial diffusivity (AD), radial diffusivity (RD), and mean diffusivity (MD) values were compared within seven skeletonised regions of interest (ROIs), i.e., corpus callosum, bilateral cingulum bundle, bilateral inferior longitudinal fasciculus/frontal-occipital fasciculus (ILF/FOF) and bilateral superior longitudinal fasciculus (SLF). Results: Un-medicated OCD patients, compared with HC, had significantly lower FA in the left cingulum bundle. FA was trend-significantly lower in all other ROIs, except for the corpus callosum. Significant three-group differences in FA (and in RD at trend-significant level) were observed in the left cingulum bundle, with the unaffected siblings representing an intermediate group between OCD patients and HC. Conclusions: OCD patients showed lower FA in the left cingulum bundle, partly driven by trend-significantly higher values in RD. Since the unaffected siblings were found to be an intermediate group between OCD patients and HC, this white matter alteration may be considered an endophenotype for OCD. PMID:26793045

  1. Interhemispheric temporal lobe connectivity predicts language impairment in adolescents born preterm

    PubMed Central

    Northam, Gemma B.; Liégeois, Frédérique; Tournier, Jacques-Donald; Croft, Louise J.; Johns, Paul N.; Chong, Wui K.; Wyatt, John S.

    2012-01-01

    Although language difficulties are common in children born prematurely, robust neuroanatomical correlates of these impairments remain to be established. This study investigated whether the greater prevalence of language problems in preterm (versus term-born) children might reflect injury to major intra- or interhemispheric white matter pathways connecting frontal and temporal language regions. To investigate this, we performed a comprehensive assessment of language and academic abilities in a group of adolescents born prematurely, some of whom had evidence of brain injury at birth (n = 50, mean age: 16 years, mean gestational age: 27 weeks) and compared them to a term-born control group (n = 30). Detailed structural magnetic resonance imaging and diffusion-tractography analyses of intrahemispheric and interhemispheric white matter bundles were performed. Analysis of intrahemispheric pathways included the arcuate fasciculus (dorsal language pathway) and uncinate fasciculus/extreme capsule (ventral language pathway). Analysis of interhemispheric pathways (in particular, connections between the temporal lobes) included the two major commissural bundles: the corpus callosum and anterior commissure. We found language impairment in 38% of adolescents born preterm. Language impairment was not related to abnormalities of the arcuate fasciculus (or its subsegments), but was associated with bilateral volume reductions in the ventral language pathway. However, the most significant volume reduction was detected in the posterior corpus callosum (splenium), which contains interhemispheric connections between the occipital, parietal and temporal lobes. Diffusion tractography showed that of the three groups of interhemispheric fibres within the splenium, only those connecting the temporal lobes were reduced. Crucially, we found that language impairment was only detectable if the anterior commissure (a second temporal lobe commissural pathway) was also small. Regression analyses showed that a combination of anatomical measures of temporal interhemispheric connectivity (through the splenium of the corpus callosum and anterior commissure) explained 57% of the variance in language abilities. This supports recent theories emphasizing the importance of interhemispheric connections for language, particularly in the developing brain. PMID:23144265

  2. White matter correlates of sensory processing in autism spectrum disorders

    PubMed Central

    Pryweller, Jennifer R.; Schauder, Kimberly B.; Anderson, Adam W.; Heacock, Jessica L.; Foss-Feig, Jennifer H.; Newsom, Cassandra R.; Loring, Whitney A.; Cascio, Carissa J.

    2014-01-01

    Autism spectrum disorder (ASD) has been characterized by atypical socio-communicative behavior, sensorimotor impairment and abnormal neurodevelopmental trajectories. DTI has been used to determine the presence and nature of abnormality in white matter integrity that may contribute to the behavioral phenomena that characterize ASD. Although atypical patterns of sensory responding in ASD are well documented in the behavioral literature, much less is known about the neural networks associated with aberrant sensory processing. To address the roles of basic sensory, sensory association and early attentional processes in sensory responsiveness in ASD, our investigation focused on five white matter fiber tracts known to be involved in these various stages of sensory processing: superior corona radiata, centrum semiovale, inferior longitudinal fasciculus, posterior limb of the internal capsule, and splenium. We acquired high angular resolution diffusion images from 32 children with ASD and 26 typically developing children between the ages of 5 and 8. We also administered sensory assessments to examine brain-behavior relationships between white matter integrity and sensory variables. Our findings suggest a modulatory role of the inferior longitudinal fasciculus and splenium in atypical sensorimotor and early attention processes in ASD. Increased tactile defensiveness was found to be related to reduced fractional anisotropy in the inferior longitudinal fasciculus, which may reflect an aberrant connection between limbic structures in the temporal lobe and the inferior parietal cortex. Our findings also corroborate the modulatory role of the splenium in attentional orienting, but suggest the possibility of a more diffuse or separable network for social orienting in ASD. Future investigation should consider the use of whole brain analyses for a more robust assessment of white matter microstructure. PMID:25379451

  3. Anatomical predictors of aphasia recovery: a tractography study of bilateral perisylvian language networks.

    PubMed

    Forkel, Stephanie J; Thiebaut de Schotten, Michel; Dell'Acqua, Flavio; Kalra, Lalit; Murphy, Declan G M; Williams, Steven C R; Catani, Marco

    2014-07-01

    Stroke-induced aphasia is associated with adverse effects on quality of life and the ability to return to work. For patients and clinicians the possibility of relying on valid predictors of recovery is an important asset in the clinical management of stroke-related impairment. Age, level of education, type and severity of initial symptoms are established predictors of recovery. However, anatomical predictors are still poorly understood. In this prospective longitudinal study, we intended to assess anatomical predictors of recovery derived from diffusion tractography of the perisylvian language networks. Our study focused on the arcuate fasciculus, a language pathway composed of three segments connecting Wernicke's to Broca's region (i.e. long segment), Wernicke's to Geschwind's region (i.e. posterior segment) and Broca's to Geschwind's region (i.e. anterior segment). In our study we were particularly interested in understanding how lateralization of the arcuate fasciculus impacts on severity of symptoms and their recovery. Sixteen patients (10 males; mean age 60 ± 17 years, range 28-87 years) underwent post stroke language assessment with the Revised Western Aphasia Battery and neuroimaging scanning within a fortnight from symptoms onset. Language assessment was repeated at 6 months. Backward elimination analysis identified a subset of predictor variables (age, sex, lesion size) to be introduced to further regression analyses. A hierarchical regression was conducted with the longitudinal aphasia severity as the dependent variable. The first model included the subset of variables as previously defined. The second model additionally introduced the left and right arcuate fasciculus (separate analysis for each segment). Lesion size was identified as the only independent predictor of longitudinal aphasia severity in the left hemisphere [beta = -0.630, t(-3.129), P = 0.011]. For the right hemisphere, age [beta = -0.678, t(-3.087), P = 0.010] and volume of the long segment of the arcuate fasciculus [beta = 0.730, t(2.732), P = 0.020] were predictors of longitudinal aphasia severity. Adding the volume of the right long segment to the first-level model increased the overall predictive power of the model from 28% to 57% [F(1,11) = 7.46, P = 0.02]. These findings suggest that different predictors of recovery are at play in the left and right hemisphere. The right hemisphere language network seems to be important in aphasia recovery after left hemispheric stroke. PMID:24951631

  4. Propylene oxide causes central-peripheral distal axonopathy in rats

    SciTech Connect

    Ohnishi, A.; Yamamoto, T.; Murai, Y.; Hayashida, Y.; Hori, H.; Tanaka, I.

    1988-09-01

    In Wistar rats subjected daily to a 6-hr exposure of propylene oxide (PO) at a concentration of 1,500 ppm (5 times a wk for 7 wk), ataxia developed in the hindlegs. Myelinated fibers in hindleg nerves and in the fasciculus gracilis showed axonal degeneration, sparing the nerve cell body of the first sacral dorsal root ganglion and myelinated fibers of the first sacral dorsal and ventral roots. These pathologic findings are compatible with central-peripheral distal axonopathy. This is apparently the first animal model of PO neuropathy to be verified histologically.

  5. Testing the white matter retrogenesis hypothesis of cognitive aging

    PubMed Central

    Brickman, Adam M.; Meier, Irene B.; Korgaonkar, Mayuresh S.; Provenzano, Frank A.; Grieve, Stuart M.; Siedlecki, Karen L.; Wasserman, Ben T.; Williams, Leanne M.; Zimmerman, Molly E.

    2011-01-01

    Background The retrogenesis hypothesis postulates that late-myelinated white matter fibers are most vulnerable to age- and disease-related degeneration, which in turn mediate cognitive decline. While recent evidence supports this hypothesis in the context of Alzheimer’s disease, it has not been tested systematically in normal cognitive aging. Methods In the current study, we examined the retrogenesis hypothesis in a group (n=282) of cognitively normal individuals ranging in age from 7 to 87 years from the Brain Resource International Database. Participants were evaluated with a comprehensive neuropsychological battery and were imaged with diffusion tensor imaging. Fractional anisotropy (FA), radial diffusivity (RD), and axial diffusivity (DA), measures of white matter coherence, were computed in two prototypical early-myelinated fiber tracts (posterior limb of the internal capsule, cerebral peduncles) and two prototypical late-myelinated fiber tracts (superior longitudinal fasciculus, inferior longitudinal fasciculus) chosen to parallel previous studies; mean summary values were also computed for other early- and late-myelinated fiber tracts. We examined age-associated differences in FA, RD, and DA in the developmental trajectory (ages 7 to 30 years) and degenerative trajectory (ages 31 to 87 years), and tested whether the measures of white matter coherence mediated age-related cognitive decline in the older group. Results FA and DA values were greater for early-myelinated fibers than for late-myelinated fibers, and RD values were lower for early-myelinated than late-myelinated fibers. There were age-associated differences in FA, RD, and DA across early- and late-myelinated fiber tracts in the younger group, but the magnitude of differences did not vary as a function of early or late myelinating status. FA and RD in most fiber tracts showed reliable age-associated differences in the older age group, but the magnitudes were greatest for the late-myelinated tract summary measure, inferior longitudinal fasciculus (late fiber tract), and cerebral peduncles (early fiber tract). Finally, FA in the inferior longitudinal fasciculus and cerebral peduncles and RD in the cerebral peduncles mediated age-associated differences in an executive functioning factor. Discussion Taken together, the findings highlight the importance of white matter coherence in cognitive aging and provide some, but not complete, support for the white matter retrogenesis hypothesis in normal cognitive aging. PMID:21783280

  6. Voxel-based assessment of gray and white matter volumes in Alzheimer's disease.

    PubMed

    Guo, Xiaojuan; Wang, Zhiqun; Li, Kuncheng; Li, Ziyi; Qi, Zhigang; Jin, Zhen; Yao, Li; Chen, Kewei

    2010-01-01

    Using the study-specific templates and optimized voxel-based morphometry (VBM), this study investigated abnormalities in gray and white matter to provide depiction of the concurrent structural changes in 13 patients with Alzheimer's disease (AD) compared with 14 age- and sex-matched normal controls. Consistent with previous studies, patients with AD exhibited significant gray matter volume reductions mainly in the hippocampus, parahippocampal gyrus, insula, superior/middle temporal gyrus, thalamus, cingulate gyrus, and superior/inferior parietal lobule. In addition, white matter volume reductions were found predominately in the temporal lobe, corpus callosum, and inferior longitudinal fasciculus. Furthermore, a number of additional white matter regions such as precentral gyrus, cingulate fasciculus, superior and inferior frontal gyrus, and sub-gyral in parietal lobe were also affected. The pattern of gray and white matter volume reductions helps us understand the underlying pathologic mechanisms in AD and potentially can be used as an imaging marker for the studies of AD in the future. PMID:19879920

  7. Cingulum Bundle Integrity Associated with Delusions of Control in Schizophrenia: Preliminary Evidence from Diffusion-Tensor Tractography

    PubMed Central

    Whitford, Thomas J.; Kubicki, Marek; Pelavin, Paula E.; Lucia, Diandra; Schneiderman, Jason S.; Pantelis, Christos; McCarley, Robert W.; Shenton, Martha E.

    2014-01-01

    Background Delusions of control are among the most distinctive and characteristic symptoms of schizophrenia. Several theories have been proposed that implicate aberrant communication between spatially disparate brain regions in the etiology of this symptom. Given that white matter fasciculi represent the anatomical infrastructure for long-distance communication in the brain, the present study investigated whether delusions of control were associated with structural abnormalities in four major white matter fasciculi. Methods Ten schizophrenia patients with current delusions of control, 13 patients with no clinical history of delusions of control, and 12 healthy controls underwent a Diffusion-Tensor Imaging (DTI) scan. Deterministic tractography was used to extract the corpus callosum, superior longitudinal fasciculus, arcuate fasciculus and cingulum bundle. The structural integrity of these four fasciculi were quantified with Fractional Anisotropy (FA), and compared between groups. Results The patients with delusions of control exhibited significantly lower FA in all four fasciculi, relative to the healthy controls. Furthermore, the patients with delusions of control also exhibited significantly lower FA in the cingulum bundle relative to patients without a history of this symptom, and this difference remained significant when controlling for between-group differences in global SAPS score and medication dosage. Conclusions The results suggest that structural damage to the cingulum bundle may be involved in the etiology of delusions of control, possibly because of its role in connecting the action initiation areas of the premotor cortex with the cingulate gyrus. PMID:25311780

  8. Analyses of Disruption of Cerebral White Matter Integrity in Schizophrenia with MR Diffusion Tensor Fiber Tracking Method

    NASA Astrophysics Data System (ADS)

    Yamamoto, Utako; Kobayashi, Tetsuo; Kito, Shinsuke; Koga, Yoshihiko

    We have analyzed cerebral white matter using magnetic resonance diffusion tensor imaging (MR-DTI) to measure the diffusion anisotropy of water molecules. The goal of this study is the quantitative evaluation of schizophrenia. Diffusion tensor images are acquired for patients with schizophrenia and healthy comparison subjects, group-matched for age, sex, and handedness. Fiber tracking is performed on the superior longitudinal fasciculus for the comparison between the patient and comparison groups. We have analysed and compared the cross-sectional area on the starting coronal plane and the mean and standard deviation of the fractional anisotropy and the apparent diffusion coefficient along fibers in the right and left hemispheres. In the right hemisphere, the cross-sectional areas in patient group are significantly smaller than those in the comparison group. Furthermore, in the comparison group, the cross-sectional areas in the right hemisphere are significantly larger than those in the left hemisphere, whereas there is no significant difference in the patient group. These results suggest that we may evaluate the disruption in white matter integrity in schizophrenic patients quantitatively by comparing the cross-sectional area of the superior longitudinal fasciculus in the right and left hemispheres.

  9. Taxonomic identity of a tetrodotoxin-accumulating ribbon-worm Cephalothrix simula (Nemertea: Palaeonemertea): a species artificially introduced from the Pacific to Europe.

    PubMed

    Kajihara, Hiroshi; Sun, Shi-Chun; Chernyshev, Alexei V; Chen, Hai-Xia; Ito, Katsutoshi; Asakawa, Manabu; Maslakova, Svetlana A; Norenburg, Jon L; Strand, Malin; Sundberg, Per; Iwata, Fumio

    2013-11-01

    We compared the anatomy of the holotype of the palaeonemertean Cephalothrix simula ( Iwata, 1952 ) with that of the holotypes of Cephalothrix hongkongiensis Sundberg, Gibson and Olsson, 2003 and Cephalothrix fasciculus ( Iwata, 1952 ), as well as additional specimens from Fukue (type locality of C. simula) and Hiroshima, Japan. While there was no major morphological discordance between these specimens, we found discrepancies between the actual morphology and some statements in the original description of C. simula with respect to supposedly species-specific characters. Our observation indicates that these three species cannot be discriminated by the anatomical characters so far used to distinguish congeners. For objectivity of scientific names, topogenetypes of the mitochondrial cytochrome c oxidase subunit I (COI) sequences are designated for C. simula, C. hongkongiensis, and C. fasciculus. Analysis of COI sequence showed that the Hiroshima population can be identified as C. simula, which has been found in previous studies from Trieste, Italy, and also from both the Mediterranean and Atlantic coasts of the Iberian Peninsula, indicating an artificial introduction via (1) ballast water, (2) ship-fouling communities, or (3) the commercially cultured oyster Crassostrea gigas ( Thunberg, 1793 ) brought from Japan to France in 1970s. Cephalothrix simula is known to be toxic, as it contains large amounts of tetrodotoxin (TTX). We report here that the grass puffer Takifugu niphobles ( Jordan and Snyder, 1901 )-also known to contain TTX- consumes C. simula. We suggest that the puffer may be able to accumulate TTX by eating C. simula. PMID:24199864

  10. Expression of Arginine Vasotocin Receptors in the Developing Zebrafish CNS

    PubMed Central

    Iwasaki, Kenichi; Taguchi, Meari; Bonkowsky, Joshua L.; Kuwada, John Y.

    2013-01-01

    Vasotocin/vasopressin is a neuropeptide that regulates social and reproductive behaviors in a variety of animals including fish. Arginine vasotocin (AVT) is expressed by cells in the ventral hypothalamic and preoptic areas in the diencephalon during embryogenesis in zebrafish suggesting that vasotocin might mediate other functions within the CNS prior to the development of social and reproductive behaviors. In order to examine potential early roles for vasotocin we cloned two zebrafish vasotocin receptors homologous to AVPR1a. The receptors are expressed primarily in the CNS in similar but generally non-overlapping patterns. Both receptors are expressed in the forebrain, midbrain and hindbrain by larval stage. Of note, AVTR1a-expressing neurons in the hindbrain appear to be contacted by the axons of preoptic neurons in the forebrain that include avt+ neurons and from sensory axons in the lateral longitudinal fasciculus (LLF). Furthermore, AVTR1a-expressing hindbrain neurons extend axons into the medial longitudinal fasciculus (MLF) that contains axons of many neurons thought to be involved in locomotor responses to sensory stimulation. One hypothesis consistent with this anatomy is that AVT signaling mediates or gates sensory input to motor circuits in the hindbrain and spinal cord. PMID:23830982

  11. Treatment Outcome-Related White Matter Differences in Veterans with Posttraumatic Stress Disorder.

    PubMed

    Kennis, Mitzy; van Rooij, Sanne J H; Tromp, Do P M; Fox, Andrew S; Rademaker, Arthur R; Kahn, René S; Kalin, Ned H; Geuze, Elbert

    2015-09-01

    Posttraumatic stress disorder (PTSD) is a debilitating disorder that has been associated with brain abnormalities, including white matter alterations. However, little is known about the effect of treatment on these brain alterations. To investigate the course of white matter alterations in PTSD, we used a longitudinal design investigating treatment effects on white matter integrity using diffusion tensor imaging (DTI). Diffusion tensor and magnetization transfer images were obtained pre- and posttreatment from veterans with (n=39) and without PTSD (n=22). After treatment, 16 PTSD patients were remitted, and 23 had persistent PTSD based on PTSD diagnosis. The dorsal and hippocampal cingulum bundle, stria terminalis, and fornix were investigated as regions of interest. Exploratory whole-brain analyses were also performed. Groups were compared with repeated-measures ANOVA for fractional anisotropy (FA), and magnetization transfer ratio. Persistently symptomatic PTSD patients had increasing FA of the dorsal cingulum over time, and at reassessment these FA values were higher than both combat controls and the remitted PTSD group. Group-by-time interactions for FA were found in the hippocampal cingulum, fornix, and stria terminalis, posterior corona radiata, and superior longitudinal fasciculus. Our results indicate that higher FA of the dorsal cingulum bundle may be an acquired feature of persistent PTSD that develops over time. Furthermore, treatment might have differential effects on the hippocampal cingulum, fornix, stria terminalis, posterior corona radiata, and superior longitudinal fasciculus in remitted vs persistent PTSD patients. This study contributes to a better understanding of the neural underpinnings of PTSD treatment outcome. PMID:25837284

  12. Sharp Curvature of Frontal Lobe White Matter Pathways in Children with Autism Spectrum Disorder: Tract-Based Morphometry Analysis

    PubMed Central

    Jeong, Jeong-Won; Kumar, Ajay; Sundaram, Senthil K.; Chugani, Harry T.; Chugani, Diane C.

    2013-01-01

    Background and Purpose As we had previously observed geometrical changes of frontal lobe association pathways in children with autism spectrum disorder (ASD), in the present study we analyzed the curvature of these white matter pathways using an objective tract based morphometry (TBM) analysis. Materials and Methods Diffusion tensor imaging (DTI) was performed in 32 children with ASD and 14 children with typical development. Curvature, fractional anisotropy (FA), axial diffusivity (AD), and radial diffusivity (RD) of bilateral arcuate fasciculus (AF), uncinate fasciculus (UF), and genu of corpus callosum (gCC) were investigated using the TBM group analysis assessed by False Discovery Rate p-value (PFDR) for multiple comparisons. Results Significantly higher curvatures were found in children with ASD especially at the parieto-temporal junction for AF (left: PFDR < 0.001; right: PFDR < 0.01), at the fronto-temporal junction for UF (left: PFDR < 0.005; right: PFDR < 0.03), and at the midline of the gCC (PFDR < 0.0001). RD was significantly higher in children with ASD at the same bending regions of AF (left: PFDR < 0.03, right: PFDR < 0.02), UF (left: PFDR < 0.04), and gCC (PFDR < 0.01). Conclusion Higher curvature and curvature dependent RD changes in children with ASD may be the result of higher density of thinner axons in these frontal lobe tracts. PMID:21757519

  13. Fronto-temporal white matter connectivity predicts reversal learning errors

    PubMed Central

    Alm, Kylie H.; Rolheiser, Tyler; Mohamed, Feroze B.; Olson, Ingrid R.

    2015-01-01

    Each day, we make hundreds of decisions. In some instances, these decisions are guided by our innate needs; in other instances they are guided by memory. Probabilistic reversal learning tasks exemplify the close relationship between decision making and memory, as subjects are exposed to repeated pairings of a stimulus choice with a reward or punishment outcome. After stimulus–outcome associations have been learned, the associated reward contingencies are reversed, and participants are not immediately aware of this reversal. Individual differences in the tendency to choose the previously rewarded stimulus reveal differences in the tendency to make poorly considered, inflexible choices. Lesion studies have strongly linked reversal learning performance to the functioning of the orbitofrontal cortex, the hippocampus, and in some instances, the amygdala. Here, we asked whether individual differences in the microstructure of the uncinate fasciculus, a white matter tract that connects anterior and medial temporal lobe regions to the orbitofrontal cortex, predict reversal learning performance. Diffusion tensor imaging and behavioral paradigms were used to examine this relationship in 33 healthy young adults. The results of tractography revealed a significant negative relationship between reversal learning performance and uncinate axial diffusivity, but no such relationship was demonstrated in a control tract, the inferior longitudinal fasciculus. Our findings suggest that the uncinate might serve to integrate associations stored in the anterior and medial temporal lobes with expectations about expected value based on feedback history, computed in the orbitofrontal cortex. PMID:26150776

  14. White matter alterations in early stages of schizophrenia: a systematic review of diffusion tensor imaging studies.

    PubMed

    Samartzis, Lampros; Dima, Danai; Fusar-Poli, Paolo; Kyriakopoulos, Marinos

    2014-01-01

    Several lines of evidence suggest that the normal integration of cerebral communication may be compromised in schizophrenia, with white matter (WM) abnormalities being integral to these functional deficits. Diffusion tensor imaging (DTI) is a neuroimaging technique which has increasingly been used to study WM through quantitative indices of its structural and orientational characteristics. Identifying the WM differences early in the course of schizophrenia may assist in prevention, early diagnosis and identification of treatment targets. In that respect, the aims of the present study were to (a) systematically review WM integrity in the early stages of schizophrenia as inferred by DTI and (b) specifically examine parameters that may affect WM: age, duration of illness and treatment. In summary, DTI studies in early schizophrenia suggest that structural dysconnectivity may be already present in recent-onset and drug-naïve patients, as well as in individuals clinically at high risk for developing schizophrenia. Although the pattern of WM differences is not totally consistent frontal, fronto-temporal and fronto-limbic connections, with tracts including the superior longitudinal fasciculus, cingulum bundle, uncinate fasciculus and corpus callosum seem to be affected. These differences may depend on the developmental stage of the subjects, the duration of illness and exposure to antipsychotic medication. PMID:23317110

  15. Frequency Mapping of Rat Spinal Cord at 7T

    NASA Astrophysics Data System (ADS)

    Chen, Evan; Rauscher, Alexander; Kozlowski, Piotr; Yung, Andrew

    2012-10-01

    The spinal cord is an integral part of the nervous system responsible for sensory, motor, and reflex control crucial to all bodily function. Due to its non-invasive nature, MRI is well matched for characterizing and imaging of spinal cord, and is used extensively for clinical applications. Recent developments in magnetic resonance imaging (MRI) at high field (7T) using phase represents a new approach of characterizing spinal cord myelin. Theory suggests that microstructure differences in myelinated white matter (WM) and non-myelinated gray matter (GM) affect MR phase, measurable frequency shifts. Data from pilot experiments using a multi-gradient echo (MGE) sequence to image rat spinal cords placed parallel to main magnetic field B0 has shown frequency shifts between not only between WM and GM, but also between specific WM tracts of the dorsal column, including the fasciculus gracilis, fasciculus cuneatus, and corticospinal tract. Using MGE, frequency maps at multiple echo times (TE) between 4ms and 22ms show a non-linear relationship between WM frequency, contrary to what was previously expected. These results demonstrate the effectiveness of MGE in revealing new information about spinal cord tissue microstructure, and lays important groundwork for in-vivo and human studies.

  16. Specific white matter tissue microstructure changes associated with obesity.

    PubMed

    Kullmann, Stephanie; Callaghan, Martina F; Heni, Martin; Weiskopf, Nikolaus; Scheffler, Klaus; Häring, Hans-Ulrich; Fritsche, Andreas; Veit, Ralf; Preissl, Hubert

    2016-01-15

    Obesity-related structural brain alterations point to a consistent reduction in gray matter with increasing body mass index (BMI) but changes in white matter have proven to be more complex and less conclusive. Hence, more recently diffusion tensor imaging (DTI) has been employed to investigate microstructural changes in white matter structure. Altogether, these studies have mostly shown a loss of white matter integrity with obesity-related factors in several brain regions. However, the variety of these obesity-related factors, including inflammation and dyslipidemia, resulted in competing influences on the DTI indices. To increase the specificity of DTI results, we explored specific brain tissue properties by combining DTI with quantitative multi-parameter mapping in lean, overweight and obese young adults. By means of multi-parameter mapping, white matter structures showed differences in MRI parameters consistent with reduced myelin, increased water and altered iron content with increasing BMI in the superior longitudinal fasciculus, anterior thalamic radiation, internal capsule and corpus callosum. BMI-related changes in DTI parameters revealed mainly alterations in mean and axial diffusivity with increasing BMI in the corticospinal tract, anterior thalamic radiation and superior longitudinal fasciculus. These alterations, including mainly fiber tracts linking limbic structures with prefrontal regions, could potentially promote accelerated aging in obese individuals leading to an increased risk for cognitive decline. PMID:26458514

  17. Gestures, Vocalizations, and Memory in Language Origins

    PubMed Central

    Aboitiz, Francisco

    2011-01-01

    This article discusses the possible homologies between the human language networks and comparable auditory projection systems in the macaque brain, in an attempt to reconcile two existing views on language evolution: one that emphasizes hand control and gestures, and the other that emphasizes auditory–vocal mechanisms. The capacity for language is based on relatively well defined neural substrates whose rudiments have been traced in the non-human primate brain. At its core, this circuit constitutes an auditory–vocal sensorimotor circuit with two main components, a “ventral pathway” connecting anterior auditory regions with anterior ventrolateral prefrontal areas, and a “dorsal pathway” connecting auditory areas with parietal areas and with posterior ventrolateral prefrontal areas via the arcuate fasciculus and the superior longitudinal fasciculus. In humans, the dorsal circuit is especially important for phonological processing and phonological working memory, capacities that are critical for language acquisition and for complex syntax processing. In the macaque, the homolog of the dorsal circuit overlaps with an inferior parietal–premotor network for hand and gesture selection that is under voluntary control, while vocalizations are largely fixed and involuntary. The recruitment of the dorsal component for vocalization behavior in the human lineage, together with a direct cortical control of the subcortical vocalizing system, are proposed to represent a fundamental innovation in human evolution, generating an inflection point that permitted the explosion of vocal language and human communication. In this context, vocal communication and gesturing have a common history in primate communication. PMID:22347184

  18. Altered white matter connectivity in never-medicated patients with schizophrenia.

    PubMed

    Mandl, René C W; Rais, Monica; van Baal, Gertrudis Caroline M; van Haren, Neeltje E M; Cahn, Wiepke; Kahn, René S; Hulshoff Pol, Hilleke E

    2013-09-01

    Numerous diffusion tensor imaging (DTI) studies have implicated white matter brain tissue abnormalities in schizophrenia. However, the vast majority of these studies included patient populations that use antipsychotic medication. Previous research showed that medication intake can affect brain morphology and the question therefore arises to what extent the reported white matter aberrations can be attributed to the disease rather than to the use of medication. In this study we included 16 medication-naïve patients with schizophrenia and compared them to 23 healthy controls to exclude antipsychotic medication use as a confounding factor. For each subject DTI scans and magnetization transfer imaging (MTI) scans were acquired. A new tract-based analysis was used that combines fractional anisoptropy (FA), mean diffusivity (MD) and magnetization transfer ratio (MTR) to examine group differences in 12 major white matter fiber bundles. Significant group differences in combined FA, MD, MTR values were found for the right uncinate fasciculus and the left arcuate fasciculus. Additional analysis revealed that the largest part of both tracts showed an increase in MTR in combination with an increase in MD for patients with schizophrenia. We interpret these group-related differences as disease-related axonal or glial aberrations that cannot be attributed to antipsychotic medication use. PMID:22461372

  19. Abnormal White Matter Integrity in Elderly Patients with Idiopathic Normal-Pressure Hydrocephalus: A Tract-Based Spatial Statistics Study.

    PubMed

    Kang, Kyunghun; Choi, Woohyuk; Yoon, Uicheul; Lee, Jong-Min; Lee, Ho-Won

    2016-01-01

    We investigated white matter integrity utilizing diffusion tensor imaging in patients with idiopathic normal-pressure hydrocephalus (INPH) who had a positive response to the cerebrospinal fluid tap test and in age- and gender-matched Alzheimer's disease (AD) patients. We enrolled 28 patients with INPH, 28 patients with AD and 20 healthy controls. Tract-based spatial statistics demonstrated that INPH patients had lower fractional anisotropy (FA) in the anterior corona radiate (bilateral), corpus callosum, superior longitudinal fasciculus (bilateral), posterior thalamic radiation (bilateral), external capsule (bilateral) and middle cerebellar peduncle in comparison with the AD and control groups. Volume-of-interest analysis revealed that INPH patients, when compared to the AD and control groups, showed higher mean diffusivity in the anterior corona radiate (bilateral), corpus callosum, superior longitudinal fasciculus (bilateral), posterior thalamic radiation (left), external capsule (bilateral) and middle cerebellar peduncle. And gait dysfunction was significantly correlated with decreased FA in the splenium of the corpus callosum and right external capsule in INPH patients. Our findings may suggest a possibility for considering microstructural changes in white matter integrity in elderly patients as potential imaging markers for differentiation between INPH and AD and may help us understand the potential pathophysiology of gait disturbances associated with INPH. PMID:26882495

  20. Voxel-based assessment of gray and white matter volumes in Alzheimer’s disease

    PubMed Central

    Guo, Xiaojuan; Wang, Zhiqun; Li, Kuncheng; Li, Ziyi; Qi, Zhigang; Jin, Zhen; Yao, Li; Chen, Kewei

    2010-01-01

    Using the study-specific templates and optimized voxel-based morphometry (VBM), this study investigated abnormalities in gray and white matter to provide depiction of the concurrent structural changes in 13 patients with Alzheimer’s disease (AD) compared with 14 age- and sex-matched normal controls. Consistent with previous studies, patients with AD exhibited significant gray matter volume reductions mainly in the hippocampus, parahippocampal gyrus, insula, superior/middle temporal gyrus, thalamus, cingulate gyrus, and superior/inferior parietal lobule. In addition, white matter volume reductions were found predominately in the temporal lobe, corpus callosum, and inferior longitudinal fasciculus. Furthermore, a number of additional white matter regions such as precentral gyrus, cingulate fasciculus, superior and inferior frontal gyrus, and sub-gyral in parietal lobe were also affected. The pattern of gray and white matter volume reductions helps us understand the underlying pathologic mechanisms in AD and potentially can be used as an imaging marker for the studies of AD in the future. PMID:19879920

  1. Structural Modifications of the Brain in Acclimatization to High-Altitude

    PubMed Central

    Zhang, Jiaxing; Yan, Xiaodan; Shi, Jinfu; Gong, Qiyong; Weng, Xuchu; Liu, Yijun

    2010-01-01

    Adaptive changes in respiratory and cardiovascular responses at high altitude (HA) have been well clarified. However, the central mechanisms underlying HA acclimatization remain unclear. Using voxel-based morphometry (VBM) and diffusion tensor imaging (DTI) with fractional anisotropy (FA) calculation, we investigated 28 Han immigrant residents (17–22 yr) born and raised at HA of 2616–4200 m in Qinghai-Tibetan Plateau for at least 17 years and who currently attended college at sea-level (SL). Their family migrated from SL to HA 2–3 generations ago and has resided at HA ever since. Control subjects were matched SL residents. HA residents (vs. SL) showed decreased grey matter volume in the bilateral anterior insula, right anterior cingulate cortex, bilateral prefrontal cortex, left precentral cortex, and right lingual cortex. HA residents (vs. SL) had significantly higher FA mainly in the bilateral anterior limb of internal capsule, bilateral superior and inferior longitudinal fasciculus, corpus callosum, bilateral superior corona radiata, bilateral anterior external capsule, right posterior cingulum, and right corticospinal tract. Higher FA values in those regions were associated with decreased or unchanged radial diffusivity coinciding with no change of longitudinal diffusivity in HA vs. SL group. Conversely, HA residents had lower FA in the left optic radiation and left superior longitudinal fasciculus. Our data demonstrates that HA acclimatization is associated with brain structural modifications, including the loss of regional cortical grey matter accompanied by changes in the white matter, which may underlie the physiological adaptation of residents at HA. PMID:20625426

  2. Longitudinal changes in white matter microstructure after heavy cannabis use.

    PubMed

    Becker, Mary P; Collins, Paul F; Lim, Kelvin O; Muetzel, R L; Luciana, M

    2015-12-01

    Diffusion tensor imaging (DTI) studies of cannabis users report alterations in brain white matter microstructure, primarily based on cross-sectional research, and etiology of the alterations remains unclear. We report findings from longitudinal voxelwise analyses of DTI data collected at baseline and at a 2-year follow-up on 23 young adult (18-20 years old at baseline) regular cannabis users and 23 age-, sex-, and IQ-matched non-using controls with limited substance use histories. Onset of cannabis use was prior to age 17. Cannabis users displayed reduced longitudinal growth in fractional anisotropy in the central and parietal regions of the right and left superior longitudinal fasciculus, in white matter adjacent to the left superior frontal gyrus, in the left corticospinal tract, and in the right anterior thalamic radiation lateral to the genu of the corpus callosum, along with less longitudinal reduction of radial diffusion in the right central/posterior superior longitudinal fasciculus, corticospinal tract, and posterior cingulum. Greater amounts of cannabis use were correlated with reduced longitudinal growth in FA as was relatively impaired performance on a measure of verbal learning. These findings suggest that continued heavy cannabis use during adolescence and young adulthood alters ongoing development of white matter microstructure, contributing to functional impairment. PMID:26602958

  3. White matter integrity is associated with alcohol cue reactivity in heavy drinkers

    PubMed Central

    Monnig, Mollie A; Thayer, Rachel E; Caprihan, Arvind; Claus, Eric D; Yeo, Ronald A; Calhoun, Vince D; Hutchison, Kent E

    2014-01-01

    Neuroimaging studies have shown that white matter damage accompanies excessive alcohol use, but the functional correlates of alcohol-related white matter disruption remain unknown. This study applied tract-based spatial statistics (TBSS) to diffusion tensor imaging (DTI) data from 332 heavy drinkers (mean age = 31.2 ± 9.4; 31% female) to obtain averaged fractional anisotropy (FA) values of 18 white matter tracts. Statistical analyses examined correlations of FA values with blood-oxygenation-level-dependent (BOLD) response to an alcohol taste cue, measured with functional magnetic resonance imaging (fMRI). FA values of nine white matter tracts (anterior corona radiata, body of corpus callosum, cingulate gyrus, external capsule, fornix, inferior frontooccipital fasciculus, posterior corona radiata, retrolenticular limb of internal capsule, and superior longitudinal fasciculus) were significantly, negatively correlated with BOLD activation in medial frontal gyrus, parahippocampal gyrus, fusiform gyrus, cingulum, thalamus, caudate, putamen, insula, and cerebellum. The inverse relation between white matter integrity and functional activation during the alcohol taste cue provides support for the hypothesis that lower white matter integrity in frontoparietal and corticolimbic networks is a factor in loss of control over alcohol consumption. PMID:24683509

  4. Determinants of Concurrent Motor and Language Recovery during Intensive Therapy in Chronic Stroke Patients: Four Single-Case Studies

    PubMed Central

    Primaßin, Annika; Scholtes, Nina; Heim, Stefan; Huber, Walter; Neuschäfer, Martina; Binkofski, Ferdinand; Werner, Cornelius J.

    2015-01-01

    Despite intensive research on mechanisms of recovery of function after stroke, surprisingly little is known about determinants of concurrent recovery of language and motor functions in single patients. The alternative hypotheses are that the two functions might either “fight for resources” or use the same mechanisms in the recovery process. Here, we present follow-up data of four exemplary patients with different base levels of motor and language abilities. We assessed functional scales and performed exact lesion analysis to examine the connection between lesion parameters and recovery potential in each domain. Results confirm that preservation of the corticospinal tracts (CSTs) is a neural predictor for good motor recovery while preservation of the arcuate fasciculus (AF) is important for a good language recovery. However, results further indicate that even patients with large lesions in CST, AF, and superior longitudinal fasciculus, respectively, are able to recover their motor/language abilities during intensive therapy. We further found some indicators of a facilitating interaction between motor and language recovery. Patients with positive improvement of motor skills after therapy also improved in language skills, while the patients with no motor improvements were not able to gain any language recovery. PMID:26500606

  5. Eel calcitonin binding site distribution and antinociceptive activity in rats

    SciTech Connect

    Guidobono, F.; Netti, C.; Sibilia, V.; Villa, I.; Zamboni, A.; Pecile, A.

    1986-03-01

    The distribution of binding site for (/sup 125/I)-eel-calcitonin (ECT) to rat central nervous system, studied by an autoradiographic technique, showed concentrations of binding in the diencephalon, the brain stem and the spinal cord. Large accumulations of grains were seen in the hypothalamus, the amygdala, in the fasciculus medialis prosencephali, in the fasciculus longitudinalis medialis, in the ventrolateral part of the periventricular gray matter, in the lemniscus medialis and in the raphe nuclei. The density of grains in the reticular formation and in the nucleus tractus spinalis nervi trigemini was more moderate. In the spinal cord, grains were scattered throughout the dorsal horns. Binding of the ligand was displaced equally by cold ECT and by salmon CT(sCT), indicating that both peptides bind to the same receptors. Human CT was much weaker than sCT in displacing (/sup 125/I)-ECT binding. The administration of ECT into the brain ventricles of rats dose-dependently induced a significant and long-lasting enhancement of hot-plate latencies comparable with that obtained with sCT. The antinociceptive activity induced by ECT is compatible with the topographical distribution of binding sites for the peptide and is a further indication that fish CTs are active in the mammalian brain.

  6. Long-Term Effects of Postearthquake Distress on Brain Microstructural Changes

    PubMed Central

    Sekiguchi, Atsushi; Kotozaki, Yuka; Nouchi, Rui; Takeuchi, Hikaru; Hanawa, Sugiko; Nakagawa, Seishu; Miyauchi, Carlos Makoto; Araki, Tsuyoshi; Sakuma, Atsushi; Taki, Yasuyuki; Kawashima, Ryuta

    2014-01-01

    Stressful events can have both short- and long-term effects on the brain. Our recent investigation identified short-term white matter integrity (WMI) changes in 30 subjects soon after the Japanese earthquake. Our findings suggested that lower WMI in the right anterior cingulum (Cg) was a pre-existing vulnerability factor and increased WMI in the left anterior Cg and uncinate fasciculus (Uf) after the earthquake was an acquired sign of postearthquake distress. However, the long-term effects on WMI remained unclear. Here, we examined the 1-year WMI changes in 25 subjects to clarify long-term effects on the WMI. We found differential FAs in the right anterior Cg, bilateral Uf, left superior longitudinal fasciculus (SLF), and left thalamus, suggesting that synaptic enhancement and shrinkage were long-term effects. Additionally, the correlation between psychological measures related to postearthquake distress and the degree of WMI alternation in the right anterior Cg and the left Uf led us to speculate that temporal WMI changes in some subjects with emotional distress occurred soon after the disaster. We hypothesized that dynamic WMI changes predict a better prognosis, whereas persistently lower WMI is a marker of cognitive dysfunction, implying the development of anxiety disorders. PMID:24551840

  7. Developmental synergy between thalamic structure and interhemispheric connectivity in the visual system of preterm infants

    PubMed Central

    Ceschin, Rafael; Wisnowski, Jessica L.; Paquette, Lisa B.; Nelson, Marvin D.; Blüml, Stefan; Panigrahy, Ashok

    2015-01-01

    Thalamic structural co-variation with cortical regions has been demonstrated in preterm infants, but its relationship to cortical function and severity of non-cystic white matter injury (non-cystic WMI) is unclear. The relationship between thalamic morphology and both cortical network synchronization and cortical structural connectivity has not been established. We tested the hypothesis that in preterm neonates, thalamic volume would correlate with primary cortical visual function and microstructural integrity of cortico-cortical visual association pathways. A total of 80 term-equivalent preterm and 44 term-born infants underwent high-resolution structural imaging coupled with visual functional magnetic resonance imaging or diffusion tensor imaging. There was a strong correlation between thalamic volume and primary visual cortical activation in preterms with non-cystic WMI (r = 0.81, p-value = 0.001). Thalamic volume also correlated strongly with interhemispheric cortico-cortical connectivity (splenium) in preterm neonates with a relatively higher severity of non-cystic WMI (p-value < 0.001). In contrast, there was lower correlation between thalamic volume and intrahemispheric cortico-cortical connectivity, including the inferior longitudinal fasciculus and inferior frontal orbital fasciculus. This study shows distinct temporal overlap in the disruption of thalamo-cortical and interhemispheric cortico-cortical connectivity in preterm infants suggesting developmental synergy between thalamic morphology and the emergence of cortical networks in the last trimester. PMID:26106571

  8. White Matter Tracts Connected to the Medial Temporal Lobe Support the Development of Mnemonic Control.

    PubMed

    Wendelken, Carter; Lee, Joshua K; Pospisil, Jacqueline; Sastre, Marcos; Ross, Julia M; Bunge, Silvia A; Ghetti, Simona

    2015-09-01

    One of the most important factors driving the development of memory during childhood is mnemonic control, or the capacity to initiate and maintain the processes that guide encoding and retrieval operations. The ability to selectively attend to and encode relevant stimuli is a particularly useful form of mnemonic control, and is one that undergoes marked improvement over childhood. We hypothesized that structural integrity of white matter tracts, in particular those connecting medial temporal lobe memory regions to other cortical areas, and/or those connecting frontal and parietal control regions, should contribute to successful mnemonic control. To test this hypothesis, we examined the relationship between structural integrity of selected white matter tracts and an experimental measure of mnemonic control, involving enhancement of memory by attention at encoding, in 116 children aged 7-11 and 25 young adults. We observed a positive relationship between integrity of uncinate fasciculus and mnemonic enhancement across age groups. In adults, but not in children, we also observed an association between mnemonic enhancement and integrity of ventral cingulum bundle and ventral fornix/fimbria. Integrity of fronto-parietal tracts, including dorsal cingulum and superior longitudinal fasciculus, was unrelated to mnemonic enhancement. PMID:24675870

  9. Developmental white matter microstructure in autism phenotype and corresponding endophenotype during adolescence

    PubMed Central

    Lisiecka, D M; Holt, R; Tait, R; Ford, M; Lai, M-C; Chura, L R; Baron-Cohen, S; Spencer, M D; Suckling, J

    2015-01-01

    During adolescence, white matter microstructure undergoes an important stage of development. It is hypothesized that the alterations of brain connectivity that have a key role in autism spectrum conditions (ASCs) may interact with the development of white matter microstructure. This interaction may be present beyond the phenotype of autism in siblings of individuals with ASC, who are 10 to 20 times more likely to develop certain forms of ASC. We use diffusion tensor imaging to examine how white matter microstructure measurements correlate with age in typically developing individuals, and how this correlation differs in n=43 adolescents with ASC and their n=38 siblings. Correlations observed in n=40 typically developing individuals match developmental changes noted in previous longitudinal studies. In comparison, individuals with ASC display weaker negative correlation between age and mean diffusivity in a broad area centred in the right superior longitudinal fasciculus. These differences may be caused either by increased heterogeneity in ASC or by temporal alterations in the group's developmental pattern. Siblings of individuals with ASC also show diminished negative correlation between age and one component of mean diffusivity—second diffusion eigenvalue—in the right superior longitudinal fasciculus. As the observed differences match for location and correlation directionality in our comparison of typically developing individuals to those with ASC and their siblings, we propose that these alterations constitute a part of the endophenotype of autism. PMID:25781228

  10. DTI Tractography and White Matter Fiber Tract Characteristics in Euthymic Bipolar I Patients and Healthy Control Subjects

    PubMed Central

    Irimia, Andrei; Leow, Alex D.; Bartzokis, George; Moody, Teena D.; Jennings, Robin G.; Alger, Jeffry R.; Van Horn, John Darrell; Altshuler, Lori L.

    2012-01-01

    With the introduction of diffusion tensor imaging (DTI), structural differences in white matter (WM) architecture between psychiatric populations and healthy controls can be systematically observed and measured. In particular, DTI-tractography can be used to assess WM characteristics over the entire extent of WM tracts and aggregated fiber bundles. Using 64-direction DTI scanning in 27 participants with bipolar disorder (BD) and 26 age-and-gender-matched healthy control subjects, we compared relative length, density, and fractional anisotrophy (FA) of WM tracts involved in emotion regulation or theorized to be important neural components in BD neuropathology. We interactively isolated 22 known white matter tracts using region-of-interest placement (TrackVis software program) and then computed relative tract length, density, and integrity. BD subjects demonstrated significantly shorter WM tracts in the genu, body and splenium of the corpus callosum compared to healthy controls. Additionally, bipolar subjects exhibited reduced fiber density in the genu and body of the corpus callosum, and in the inferior longitudinal fasciculus bilaterally. In the left uncinate fasciculus, however, BD subjects exhibited significantly greater fiber density than healthy controls. There were no significant differences between groups in WM tract FA for those tracts that began and ended in the brain. The significance of differences in tract length and fiber density in BD is discussed. PMID:23070746

  11. White matter alterations associated with suicide in patients with schizophrenia or schizophreniform disorder.

    PubMed

    Lee, Sung-Jae; Kim, Borah; Oh, Daeyoung; Kim, Min-Kyoung; Kim, Keun-Hyang; Bang, Seong Yun; Choi, Tai Kiu; Lee, Sang-Hyuk

    2016-02-28

    The risk of suicide is disproportionately high among people diagnosed with schizophrenia or schizophreniform disorder. Brain imaging studies have shown a few relationships between neuroanatomy and suicide. This study examines the relationship between alterations in brain white matter (WM) and suicidal behavior in people with schizophrenia or schizophreniform disorder. The study participants were 56 patients with schizophrenia or schizophreniform disorder, with (n=15) and without (n=41) a history of suicide attempts. Fractional anisotropy (FA) values were compared between suicide attempters and non-attempters using Tract-Based Spatial Statistics (TBSS). Attempters showed significantly higher FA values than non-attempters in the left corona radiata, the superior longitudinal fasciculus, the posterior limb and retrolenticular part of the internal capsule, the external capsule, the insula, the posterior thalamic radiation, the cerebral peduncle, the sagittal stratum, and temporal lobe WM. Scores of the picture arrangement test showed a significant positive correlation with FA values of the right corona radiata, the right superior longitudinal fasciculus, the body of the corpus callosum, and the left corona radiata in attempters but not in non-attempters. These findings suggest that fronto-temporo-limbic circuits can be associated mainly with suicidal behavior in people with schizophrenia or schizophreniform disorder. PMID:26774424

  12. Improved Fronto-Parietal White Matter Integrity in Overweight Children is Associated with Attendance in an After-School Exercise Program

    PubMed Central

    Krafft, Cynthia E.; Schaeffer, David J.; Schwarz, Nicolette F.; Chi, Lingxi; Weinberger, Abby L.; Pierce, Jordan E.; Rodrigue, Amanda L.; Allison, Jerry D.; Yanasak, Nathan E.; Liu, Tianming; Davis, Catherine L.; McDowell, Jennifer E.

    2014-01-01

    Aerobic fitness is associated with white matter integrity (WMI) in adults as measured by diffusion tensor imaging (DTI). This study examined the effect of an 8-month exercise intervention on WMI in children. Participants were 18 sedentary, overweight (body mass index ? 85th percentile) 8- to 11-year-old children (94% Black), randomly assigned to either an aerobic exercise (n=10) or sedentary attention control group (n=8). Each group was offered an instructor-led after-school program every school day for approximately 8 months. Before and after the program, all subjects participated in DTI scans. Tractography was conducted to isolate the superior longitudinal fasciculus and investigate whether the exercise intervention affected WMI in this region. There was no group by time interaction for WMI in the superior longitudinal fasciculus. There was a group by time by attendance interaction, however, such that higher attendance at the exercise intervention, but not the control intervention, was associated with increased WMI. Heart rate and the total dose of exercise correlated with WMI changes in the exercise group. In the overall sample, increased WMI was associated with improved scores on a measure of attention and improved teacher ratings of executive function. This study indicates that participating in an exercise intervention improves WMI in children as compared to a sedentary after-school program. PMID:24457421

  13. Specific white matter tissue microstructure changes associated with obesity

    PubMed Central

    Kullmann, Stephanie; Callaghan, Martina F.; Heni, Martin; Weiskopf, Nikolaus; Scheffler, Klaus; Häring, Hans-Ulrich; Fritsche, Andreas; Veit, Ralf; Preissl, Hubert

    2016-01-01

    Obesity-related structural brain alterations point to a consistent reduction in gray matter with increasing body mass index (BMI) but changes in white matter have proven to be more complex and less conclusive. Hence, more recently diffusion tensor imaging (DTI) has been employed to investigate microstructural changes in white matter structure. Altogether, these studies have mostly shown a loss of white matter integrity with obesity-related factors in several brain regions. However, the variety of these obesity-related factors, including inflammation and dyslipidemia, resulted in competing influences on the DTI indices. To increase the specificity of DTI results, we explored specific brain tissue properties by combining DTI with quantitative multi-parameter mapping in lean, overweight and obese young adults. By means of multi-parameter mapping, white matter structures showed differences in MRI parameters consistent with reduced myelin, increased water and altered iron content with increasing BMI in the superior longitudinal fasciculus, anterior thalamic radiation, internal capsule and corpus callosum. BMI-related changes in DTI parameters revealed mainly alterations in mean and axial diffusivity with increasing BMI in the corticospinal tract, anterior thalamic radiation and superior longitudinal fasciculus. These alterations, including mainly fiber tracts linking limbic structures with prefrontal regions, could potentially promote accelerated aging in obese individuals leading to an increased risk for cognitive decline. PMID:26458514

  14. Fronto-temporal white matter connectivity predicts reversal learning errors.

    PubMed

    Alm, Kylie H; Rolheiser, Tyler; Mohamed, Feroze B; Olson, Ingrid R

    2015-01-01

    Each day, we make hundreds of decisions. In some instances, these decisions are guided by our innate needs; in other instances they are guided by memory. Probabilistic reversal learning tasks exemplify the close relationship between decision making and memory, as subjects are exposed to repeated pairings of a stimulus choice with a reward or punishment outcome. After stimulus-outcome associations have been learned, the associated reward contingencies are reversed, and participants are not immediately aware of this reversal. Individual differences in the tendency to choose the previously rewarded stimulus reveal differences in the tendency to make poorly considered, inflexible choices. Lesion studies have strongly linked reversal learning performance to the functioning of the orbitofrontal cortex, the hippocampus, and in some instances, the amygdala. Here, we asked whether individual differences in the microstructure of the uncinate fasciculus, a white matter tract that connects anterior and medial temporal lobe regions to the orbitofrontal cortex, predict reversal learning performance. Diffusion tensor imaging and behavioral paradigms were used to examine this relationship in 33 healthy young adults. The results of tractography revealed a significant negative relationship between reversal learning performance and uncinate axial diffusivity, but no such relationship was demonstrated in a control tract, the inferior longitudinal fasciculus. Our findings suggest that the uncinate might serve to integrate associations stored in the anterior and medial temporal lobes with expectations about expected value based on feedback history, computed in the orbitofrontal cortex. PMID:26150776

  15. Involvement of the right hemisphere in reading comprehension: a DTI study.

    PubMed

    Horowitz-Kraus, Tzipi; Wang, Yingying; Plante, Elena; Holland, Scott K

    2014-09-25

    The Simple View of reading emphasizes the critical role of two factors in normal reading skills: word recognition and reading comprehension. The current study aims to identify the anatomical support for aspects of reading performance that fall within these two components. Fractional anisotropy (FA) values were obtained from diffusion tensor images in twenty-one typical adolescents and young adults using the tract based spatial statistics (TBSS) method. We focused on the arcuate fasciculus (AF) and inferior longitudinal fasciculus (ILF) as fiber tracts that connect regions already implicated in the distributed cortical network for reading. Our results demonstrate dissociation between word-level and narrative-level reading skills: the FA values for both left and right ILF were correlated with measures of word reading, while only the left ILF correlated with reading comprehension scores. FA in the AF, however, correlated only with reading comprehension scores, bilaterally. Correlations with the right AF were particularly robust, emphasizing the contribution of the right hemisphere, especially the frontal lobe, to reading comprehension performance on the particular passage comprehension test used in this study. The anatomical dissociation between these reading skills is supported by the Simple View theory and may shed light on why these two skills dissociate in those with reading disorders. PMID:24909792

  16. Right is not always wrong: DTI and fMRI evidence for the reliance of reading comprehension on language-comprehension networks in the right hemisphere.

    PubMed

    Horowitz-Kraus, Tzipi; Grainger, Molly; DiFrancesco, Mark; Vannest, Jennifer; Holland, Scott K

    2015-03-01

    The Simple View theory suggests that reading comprehension relies on automatic recognition of words combined with language comprehension. The goal of the current study was to examine the structural and functional connectivity in networks supporting reading comprehension and their relationship with language comprehension within 7-9 year old children using Diffusion Tensor Imaging (DTI) and fMRI during a Sentence Picture Matching task. Fractional Anisotropy (FA) values in the left and right Inferior Longitudinal Fasciculus (ILF) and Superior Longitudinal Fasciculus (SLF), known language-related tracts, were correlated from DTI data with scores from the Woodcock-Johnson III (WJ-III) Passage Comprehension sub-test. Brodmann areas most proximal to white-matter regions with significant correlation to Passage Comprehension scores were chosen as Regions-of-Interest (ROIs) and used as seeds in a functional connectivity analysis using the Sentence Picture Matching task. The correlation between percentile scores for the WJ-III Passage Comprehension subtest and the FA values in the right and left ILF and SLF indicated positive correlation in language-related ROIs, with greater distribution in the right hemisphere, which in turn showed strong connectivity in the fMRI data from the Sentence Picture Matching task. These results support the participation of the right hemisphere in reading comprehension and may provide physiologic support for a distinction between different types of reading comprehension deficits vs difficulties in technical reading. PMID:25515348

  17. Reduced white matter integrity and verbal fluency impairment in young adults with bipolar disorder: a diffusion tensor imaging study

    PubMed Central

    Bauer, Isabelle E.; Ouyang, Austin; Mwangi, Benson; Sanches, Marsal; Zunta-Soares, Giovana B.; Keefe, Richard S. E.; Huang, Hao; Soares, Jair C.

    2015-01-01

    Background Clinical evidence shows that bipolar disorder (BD) is characterized by white matter (WM) microstructural abnormalities. However, little is known about the biological mechanisms associated with these abnormalities and their relationship with cognitive functioning. Methods 49 adult BD patients ((M±SD): 29.27 ± 7.92 years; 17 males, 32 females; 34 BD-I, 10 BD-II, and 5 BD-NOS) and 28 age-matched normal subjects ((M±SD): 29.19 ± 7.35 years; 10 males and 18 females) underwent diffusion tensor imaging (DTI) imaging. DTI metrics were computed using whole-brain tract-based spatial statistics (TBSS) as part of the FMRIB Software Library. Measures of WM coherence (fractional anisotropy - FA) and axonal structure (mean, axial and radial diffusivity - MD, AD and RD) were employed to characterize the microstructural alterations in the limbic, commissural, association and projection fiber tracts. All participants performed the Brief Assessment of Cognition for Affective disorders (BAC-A). Results BD patients performed poorly on verbal fluency tasks and exhibited large clusters of altered FA, RD and MD values within the retrolenticular part of the internal capsule, the superior and anterior corona radiata, and the corpus callosum. Increased FA values in the left IFOF and the forceps minor correlated positively with verbal fluency scores. Altered RD parameters in the corticospinal tract and the forceps minor were associated with reduced visuomotor abilities. Conclusions The reported verbal fluency deficits and FA, RD and MD alterations in WM structures are potential cognitive and neural markers of BD. Abnormal RD values may be associated with progressive demyelination. PMID:25684152

  18. White Matter Structure in Youth with Behavioral and Emotional Dysregulation Disorders: a Probabilistic Tractographic Study

    PubMed Central

    Versace, Amelia; Acuff, Heather; Bertocci, Michele A.; Bebko, Genna; Almeida, Jorge R. C.; Perlman, Susan B.; Leemans, Alexander; Schirda, Claudiu; Aslam, Haris; Dwojak, Amanda; Bonar, Lisa; Travis, Michael; Gill, Mary Kay; Demeter, Christine; Diwadkar, Vaibhav A.; Sunshine, Jeffrey L.; Holland, Scott K; Kowatch, Robert. A.; Birmaher, Boris; Axelson, David; Horwitz, Sarah M.; Frazier, Thomas W.; Arnold, L. Eugene; Fristad, Mary. A; Youngstrom, Eric A.; Findling, Robert L.; Phillips, Mary L.

    2015-01-01

    Importance Psychiatric disorders in youth characterized by behavioral and emotional dysregulation are often comorbid and difficult to distinguish. An alternative approach to conceptualizing these disorders is to move toward a diagnostic system based on underlying pathophysiologic processes that may cut across conventionally defined diagnoses. Neuroimaging techniques have potentials for the identification of these processes. Objective To determine whether diffusion imaging can identify neural correlates of emotional dysregulation in a sample of youth with a variety of different psychiatric disorders characterized by behavioral and emotional dysregulation. Design, Setting, and Participants Start date = 07/01/10; End date = 02/28/15. We examined relationships between WM structure in key tracts in emotional regulation circuitry and: 1).Broader-diagnostic categories of behavioral and emotional dysregulation disorders (DDs); and 2).Symptom dimensions cutting across conventional diagnoses in 120 youth with behavioral and/or emotional DDs. Thirty typically developing youth (control participants) were included. Main Outcome Measure(s) Using global probabilistic tractography, key WM tracts in emotional regulation circuitry (ie, cingulum, uncinate fasciculus, and forceps minor) were reconstructed. Fractional anisotropy (and axial or radial diffusivity) was estimated, and values were imported into a well-established statistical package. We hypothesized that (1).Youth with emotional DDs, and those with both behavioral and emotional DDs, would show significantly lower fractional anisotropy compared with youth with behavioral DDs in these WM tracts, and (2) that there would be significant inverse relationships between dimensional measures of affective symptom severity and fractional anisotropy in these tracts across all participants. Results Multivariate multiple regression analyses revealed statistically significantly decreased fractional anisotropy and decreased axial, but not increased radial, diffusivity, within the uncinate fasciculus, in youth with emotional DDs vs. those with-behavioral DDs, vs those with both DDs, and vs controls (F P all pairwise comparisons, p<0.002). In the same model, greater severity of manic symptoms was positively associated with higher fractional anisotropy across all affected youth (F P p=0.043). Conclusions and Relevance The findings of the present study suggest that abnormal uncinate fasciculus and cingulum WM structure may underlie emotional, but not behavioral, dysregulation in pediatric psychiatric disorders, and that a different neural mechanism may exist for comorbid (emotional and behavioral) DDs. PMID:25715064

  19. Signalling properties of identified deep cerebellar nuclear neurons related to eye and head movements in the alert cat.

    PubMed Central

    Gruart, A; Delgado-García, J M

    1994-01-01

    1. The spike activity of deep cerebellar nuclear neurons was recorded in the alert cat during spontaneous and during vestibularly and visually induced eye movements. 2. Neurons were classified according to their location in the nuclei, their antidromic activation from projection sites, their sensitivity to eye position and velocity during spontaneous eye movements, and their responses to vestibular and optokinetic stimuli. 3. Type I EPV (eye position and velocity) neurons were located mainly in the posterior part of the fastigial nucleus and activated antidromically almost exclusively from the medial longitudinal fasciculus close to the oculomotor complex. These neurons, reported here for the first time, increased their firing rate during saccades and eye fixations towards the contralateral hemifield. Their position sensitivity to eye fixations in the horizontal plane was 5.3 +/- 2.6 spikes s-1 deg-1 (mean +/- S.D.). Eye velocity sensitivity during horizontal saccades was 0.71 +/- 0.52 spikes s-1 deg-1 s-1. Variability of their firing rate during a given eye fixation was higher than that shown by abducens motoneurons. 4. Type I EPV neurons increased their firing rate during ipsilateral head rotations at 0.5 Hz with a mean phase lead over eye position of 95.3 +/- 9.5 deg. They were also activated by contralateral optokinetic stimulation at 30 deg s-1. Their sensitivity to eye position and velocity in the horizontal plane during vestibular and optokinetic stimuli yielded values similar to those obtained for spontaneous eye movements. 5. Type II neurons were located in both fastigial and dentate nuclei and were activated antidromically from the restiform body, the medial longitudinal fasciculus close to the oculomotor complex, the red nucleus and the pontine nuclei. Type II neurons were not related to spontaneous eye movements. These neurons increased their firing rate in response to contralateral head rotation and during ipsilateral optokinetic stimulation, and decreased it with the oppositely directed movements. 6. Saccade-related neurons were located mostly in the fastigial and dentate nuclei. Fastigial neurons were activated antidromically from the medial longitudinal fasciculus, while dentate neurons were activated from the red nucleus. These neurons fired a burst of spikes whose duration was significantly related to saccade duration. Dentate neurons responded during the omni-directional saccades, while some fastigial neurons fired more actively during contralateral saccades. 7. These three types of neuron represent the output channel for oculomotor signals of the posterior vermis and paravermis. It is proposed that type I EPV neurons correspond to a group of premotor neurons directly involved in oculomotor control.(ABSTRACT TRUNCATED AT 400 WORDS) PMID:7965834

  20. Frontal fasciculi and psychotic symptoms in antipsychotic-naive patients with schizophrenia before and after 6 weeks of selective dopamine D2/3 receptor blockade

    PubMed Central

    Ebdrup, Bjørn H.; Raghava, Jayachandra M.; Nielsen, Mette Ø.; Rostrup, Egill; Glenthøj, Birte

    2016-01-01

    Background Psychotic symptoms are core clinical features of schizophrenia. We tested recent hypotheses proposing that psychotic, or positive, symptoms stem from irregularities in long-range white matter tracts projecting into the frontal cortex, and we predicted that selective dopamine D2/3 receptor blockade would restore white matter. Methods Between December 2008 and July 2011, antipsychoticnaive patients with first-episode schizophrenia and matched healthy controls underwent baseline examination with 3 T MRI diffusion tensor imaging and clinical assessments. We assessed group differences of fractional anisotropy (FA) using voxelwise tract-based spatial statistics (TBSS) and anatomic region of interest (ROI)–based analyses. Subsequently, patients underwent 6 weeks of antipsychotic monotherapy with amisulpride. We repeated the examinations after 6 weeks. Results We included 38 patients with first-episode schizophrenia and 38 controls in our analysis, and 28 individuals in each group completed the study. At baseline, whole brain TBSS analyses revealed lower FA in patients in the right anterior thalamic radiation (ATR), right cingulum, right inferior longitudinal fasciculus and right corticospinal tract (CT). Fractional anisotropy in the right ATR correlated with positive symptoms (z = 2.64, p = 0.008). The ROI analyses showed significant associations between positive symptoms and FA of the frontal fasciculi, specifically the right arcuate fasciculus (z = 2.83, p = 0.005) and right superior longitudinal fasciculus (z = −3.31, p = 0.001). At re-examination, all correlations between positive symptoms and frontal fasciculi had resolved. Fractional anisotropy in the ATR increased more in patients than in controls (z = −4.92, p < 0.001). The amisulpride dose correlated positively with FA changes in the right CT (t = 2.52, p = 0.019). Limitations Smoking and a previous diagnosis of substance abuse were potential confounders. Long-term effects of amisulpride on white matter were not evaluated. Conclusion Antipsychotic-naive patients with schizophrenia displayed subtle deficits in white matter, and psychotic symptoms appeared specifically associated with frontal fasciculi integrity. Six weeks of amisulpride treatment normalized white matter. Potential re-myelinating effects of dopamine D2/3 receptor antagonism warrant further clarification. PMID:26599135

  1. Age-Related Differences and Heritability of the Perisylvian Language Networks

    PubMed Central

    Dell'Acqua, Flavio; Rijsdijk, Frühling V.; Kane, Fergus; Picchioni, Marco; McGuire, Philip; Toulopoulou, Timothea; Georgiades, Anna; Kalidindi, Sridevi; Kravariti, Eugenia; Murray, Robin M.; Murphy, Declan G.; Craig, Michael C.

    2015-01-01

    Acquisition of language skills depends on the progressive maturation of specialized brain networks that are usually lateralized in adult population. However, how genetic and environmental factors relate to the age-related differences in lateralization of these language pathways is still not known. We recruited 101 healthy right-handed subjects aged 9–40 years to investigate age-related differences in the anatomy of perisylvian language pathways and 86 adult twins (52 monozygotic and 34 dizygotic) to understand how heritability factors influence language anatomy. Diffusion tractography was used to dissect and extract indirect volume measures from the three segments of the arcuate fasciculus connecting Wernicke's to Broca's region (i.e., long segment), Broca's to Geschwind's region (i.e., anterior segment), and Wernicke's to Geschwind's region (i.e., posterior segment). We found that the long and anterior arcuate segments are lateralized before adolescence and their lateralization remains stable throughout adolescence and early adulthood. Conversely, the posterior segment shows right lateralization in childhood but becomes progressively bilateral during adolescence, driven by a reduction in volume in the right hemisphere. Analysis of the twin sample showed that genetic and shared environmental factors influence the anatomy of those segments that lateralize earlier, whereas specific environmental effects drive the variability in the volume of the posterior segment that continues to change in adolescence and adulthood. Our results suggest that the age-related differences in the lateralization of the language perisylvian pathways are related to the relative contribution of genetic and environmental effects specific to each segment. SIGNIFICANCE STATEMENT Our study shows that, by early childhood, frontotemporal (long segment) and frontoparietal (anterior segment) connections of the arcuate fasciculus are left and right lateralized, respectively, and remain lateralized throughout adolescence and early adulthood. In contrast, temporoparietal (posterior segment) connections are right lateralized in childhood, but become progressively bilateral during adolescence. Preliminary twin analysis suggested that lateralization of the arcuate fasciculus is a heterogeneous process that depends on the interplay between genetic and environment factors specific to each segment. Tracts that exhibit higher age effects later in life (i.e., posterior segment) appear to be influenced more by specific environmental factors. PMID:26377454

  2. The impact of depression on Veterans with PTSD and traumatic brain injury: a diffusion tensor imaging study.

    PubMed

    Isaac, Linda; Main, Keith L; Soman, Salil; Gotlib, Ian H; Furst, Ansgar J; Kinoshita, Lisa M; Fairchild, J Kaci; Yesavage, Jerome A; Ashford, J Wesson; Bayley, Peter J; Adamson, Maheen M

    2015-02-01

    A significant proportion of military personnel deployed in support of Operation Enduring Freedom and Operation Iraqi Freedom were exposed to war-zone events associated with traumatic brain injury (TBI), depression (DEP) and posttraumatic stress disorder (PTSD). The co-occurrence of TBI, PTSD and DEP in returning Veterans has recently increased research and clinical interest. This study tested the hypothesis that white matter abnormalities are further impacted by depression. Of particular relevance is the uncinate fasciculus (UF), which is a key fronto-temporal tract involved in mood regulation, and the cingulum; a tract that connects to the hippocampus involved in memory integration. Diffusion tensor imaging (DTI) was performed on 25 patients with a combination of PTSD, TBI and DEP and 20 patients with PTSD and TBI (no DEP). Microstructural changes of white matter were found in the cingulum and UF. Fractional anisotropy (FA) was lower in Veterans with DEP compared to those without DEP. PMID:25559772

  3. Fiber Pathways of Attention Subnetworks Revealed with Tract-Based Spatial Statistics (TBSS) and Probabilistic Tractography

    PubMed Central

    Ge, Haitao; Yin, Xuntao; Xu, Junhai; Tang, Yuchun; Han, Yan; Xu, Wenjian; Pang, Zengchang; Meng, Haiwei; Liu, Shuwei

    2013-01-01

    It has been widely accepted that attention can be divided into three subnetworks - alerting, orienting and executive control (EC), and the subnetworks of attention are linked to distinct brain regions. However, the association between specific white matter fibers and the subnetworks of attention is not clear enough. Using diffusion tensor imaging (DTI), the white matter connectivity related to the performance of attention was assessed by attention network test (ANT) in 85 healthy adolescents. Tract-based spatial statistics (TBSS) and probabilistic diffusion tractography analysis demonstrated that cerebellothalamic tract was involved in alerting, while orienting depended upon the superior longitudinal fasciculus (SLF). In addition, EC was under the control of anterior corona radiata (ACR). Our findings suggest that different fiber pathways are involved in the three distinct subnetworks of attention. The current study will yield more precise information about the structural substrates of attention function and may aid the efforts to understand the neurophysiology of several attention disorders. PMID:24223852

  4. Patterns of dissociate torsional-vertical nystagmus in internuclear ophthalmoplegia.

    PubMed

    Jeong, Seong-Hae; Kim, Eung Kyu; Lee, Jun; Choi, Kwang-Dong; Kim, Ji Soo

    2011-09-01

    To explore the patterns and mechanisms of jerky seesaw nystagmus in internuclear ophthalmoplegia (INO), we analyzed the nystagmus patterns in 33 patients with dissociated torsional-vertical nystagmus and INO. In 11 (33%) patients, the nystagmus was ipsiversive torsional in both eyes with vertical components in the opposite directions. In contrast, 18 (55%) patients showed ipsiversive torsional nystagmus with a larger upbeat component in the contralesional eye. Four (12%) patients exhibited ipsiversive torsional nystagmus with a greater downbeat component in the ipsilesional eye. At least one component of contraversive ocular tilt reaction was associated in most patients (30/33, 91%). The patterns of jerky seesaw nystagmus in INO suggest a disruption of neural pathways from the contralateral vertical semicircular canals with or without concomitant damage to the fibers from the contralateral utricle in or near the medial longitudinal fasciculus. PMID:21951004

  5. A Preliminary Study of the Effects of an Arts Education Program on Executive Function, Behavior, and Brain Structure in a Sample of Nonclinical School-Aged Children.

    PubMed

    Park, Subin; Lee, Jong-Min; Baik, Young; Kim, Kihyun; Yun, Hyuk Jin; Kwon, Hunki; Jung, Yeon-Kyung; Kim, Bung-Nyun

    2015-11-01

    The authors examined the effects of arts education on cognition, behavior, and brain of children. Twenty-nine nonclinical children participated in a 15-week arts education program that was composed of either creative movement or musical arts. Children completed the Wisconsin Card Sorting Test, clinical scales, and brain magnetic resonance imaging before and after the intervention. Following program completion, performances on the Wisconsin Card Sorting Test, the Children's Depression Inventory scores, and conduct disorder scores were significantly improved. Furthermore, cortical thickness in the left postcentral gyrus and superior parietal lobule were increased, and the mean diffusivity values in the right posterior corona radiate and superior longitudinal fasciculus were decreased. Positive correlations between changes in cognitive measurements and changes in cortical thickness were observed. This preliminary study suggests a positive effect of arts education on executive functions in association with brain changes. However, these findings must be interpreted with caution due to the noncomparative study design. PMID:25862737

  6. Social cognition and the anterior temporal lobes: a review and theoretical framework

    PubMed Central

    McCoy, David; Klobusicky, Elizabeth; Ross, Lars A.

    2013-01-01

    Memory for people and their relationships, along with memory for social language and social behaviors, constitutes a specific type of semantic memory termed social knowledge. This review focuses on how and where social knowledge is represented in the brain. We propose that portions of the anterior temporal lobe (ATL) play a critical role in representing and retrieving social knowledge. This includes memory about people, their names and biographies and more abstract forms of social memory such as memory for traits and social concepts. This hypothesis is based on the convergence of several lines of research including anatomical findings, lesion evidence from both humans and non-human primates and neuroimaging evidence. Moreover, the ATL is closely interconnected with cortical nuclei of the amygdala and orbitofrontal cortex via the uncinate fasciculus. We propose that this pattern of connectivity underlies the function of the ATL in encoding and storing emotionally tagged knowledge that is used to guide orbitofrontal-based decision processes. PMID:23051902

  7. Projections from the rostral mesencephalic reticular formation to the spinal cord - An HRP and autoradiographical tracing study in the cat

    NASA Technical Reports Server (NTRS)

    Holstege, G.; Cowie, R. J.

    1989-01-01

    Horseradish peroxidase was injected, or implanted unilaterally, into various levels of the spinal cord of anesthetized cats, to trace the distribution of projections to the spinal cord, of neurons in Field H of Forel, including the rostral interstitial nucleus of the medial longitudinal fasciculus (riMLF), and the interstitial nucleus of Cajal with adjacent reticular formation (INC-RF). Results indicate that, unlike the neurons projecting to the extraocular muscle motoneurons, the major portion of the spinally projecting neurons are not located in the riMLF or INC proper, but in adjacent areas, i.e., the ventral and lateral parts of the caudal third of the Field H of Forel and in the INC-RF. Neurons in caudal Field H of Forel, project, via the ventral part of the ventral funicululs, to the lateral part of the upper cervical ventral horn.

  8. Autonomic and sensory ganglionopathy occurring in a patient with fulminant type 1 diabetes mellitus.

    PubMed

    Makino, Mutsuki; Hiwatashi, Dai; Minemura, Kesami; Kawaguchi, Kenji

    2016-02-01

    A 63-year-old male with a previous infection was admitted to our hospital because of acute pancreatitis. Although he had no history of diabetes mellitus, laboratory examinations revealed marked hyperglycemia on admission, and intensive insulin treatment was required. After 2 weeks, he developed severe pandysautonomia and sensory impairment, and eventually died from colonic perforation caused by paralytic ileus at 1 year after onset. Autopsy findings showed a complete loss of pancreatic islet beta cells with mild fibrosis of the exocrine pancreas. Neuropathological examination showed myelin loss of the dorsal fasciculus at all levels of the spinal cord and ganglionopathy of the dorsal root and sympathetic truncus, revealing degeneration of ganglion cells and a decrease in their number with the formation of Nageotte nodules. On the basis of this clinicopathological evidence, fulminant type 1 diabetes mellitus (T1DM) and idiopathic immune-mediated autonomic neuropathy were suspected. Here, we suggest a close etiological relationship between both diseases. PMID:26698638

  9. Existence of a GnRH immunoreactive nucleus in the dorsal midbrain tegmentum of the chameleon.

    PubMed

    Bennis, M; Dubourg, P; Gamrani, H; Calas, A; Kah, O

    1989-08-01

    The GnRH system of the chameleon brain was studied at light microscopic and ultrastructural levels by use of an immunohistochemical technique with antibodies directed against salmon gonadotrophin-releasing hormone. Immunoreactive (IR) perikarya were found in the anterior midbrain tegmentum. At this level numerous IR cell bodies were detected around the fasciculus longitudinalis medialis (FLM). The more rostral neurons were observed dorsal to the FLM and progressively tended to be lateral to it along the midline. More caudally, they were found ventral to the FLM. At the electron microscope level, these cells were seen to contain large granular vesicles and to receive numerous synaptic inputs. A prominent pathway was traced from these cell bodies along the medulla oblongata to the spinal cord. A second IR pathway ascended rostrally to the habenular complex. No IR perikarya were located in the anterior brain including the olfactory bulbs. PMID:2680752

  10. Eight and a half syndrome with hemiparesis and hemihypesthesia: the nine syndrome?

    PubMed

    Rosini, Francesca; Pretegiani, Elena; Guideri, Francesca; Cerase, Alfonso; Rufa, Alessandra

    2013-11-01

    "Eight-and-a-half" syndrome is "one-and-a-half" syndrome (conjugated horizontal gaze palsy and internuclear ophthalmoplegia) plus ipsilateral fascicular cranial nerve seventh palsy. This rare condition, particularly when isolated, is caused by circumscribed lesions of the pontine tegmentum involving the abducens nucleus, the ipsilateral medial longitudinal fasciculus, and the adjacent facial colliculus. Its recognition is therefore of considerable diagnostic value. We report a 71-year-old man who presented with eight and a half syndrome associated with contralateral hemiparesis and hemihypesthesia, in which brain magnetic resonance imaging scans revealed a lacunar pontine infarction also involving the corticospinal tract and medial lemniscus. These features could widen the spectrum of pontine infarctions, configuring a possible "nine" syndrome. PMID:23434442

  11. Vertical supranuclear gaze palsy in Niemann-Pick type C disease.

    PubMed

    Salsano, Ettore; Umeh, Chizoba; Rufa, Alessandra; Pareyson, Davide; Zee, David S

    2012-12-01

    Vertical supranuclear gaze palsy (VSGP) is a key clinical feature in patients with Niemann-Pick type C disease (NP-C), a rare, autosomal recessive, neuro-visceral disorder caused by mutations in either the NPC1 or NPC2 gene. VSGP is present in approximately 65 % of the cases and is, with gelastic cataplexy, an important risk indicator for NP-C. VSGP in NP-C is characterized by a paralysis of vertical saccades, especially downward, with the slow vertical eye movement systems (smooth pursuit and the vestibulo-ocular reflex) spared in the early phase of the disease. This dissociation is caused by a selective vulnerability of the neurons in the rostral interstitial nuclei of the medial longitudinal fasciculus (riMLF) in NP-C. Here we discuss VSGP in NP-C and how clinicians can best elicit this sign. PMID:22810120

  12. A model for Social Communication And Language Evolution and Development (SCALED).

    PubMed

    Catani, Marco; Bambini, Valentina

    2014-10-01

    In humans, brain connectivity implements a system for language and communication that spans from basic pre-linguistic social abilities shared with non-human primates to syntactic and pragmatic functions particular to our species. The arcuate fasciculus is a central connection in this architecture, linking regions devoted to formal aspects of language with regions involved in intentional and social communication. Here, we outline a new anatomical model of communication that incorporates previous neurofunctional accounts of language with recent advances in tractography and neuropragmatics. The model consists of five levels, from the representation of informative actions and communicative intentions, to lexical/semantic processing, syntactic analysis, and pragmatic integration. The structure of the model is hierarchical in relation to developmental and evolutionary trajectories and it may help interpreting clinico-anatomical correlation in communication disorders. PMID:25156623

  13. White matter morphometric changes uniquely predict children's reading acquisition.

    PubMed

    Myers, Chelsea A; Vandermosten, Maaike; Farris, Emily A; Hancock, Roeland; Gimenez, Paul; Black, Jessica M; Casto, Brandi; Drahos, Miroslav; Tumber, Mandeep; Hendren, Robert L; Hulme, Charles; Hoeft, Fumiko

    2014-10-01

    This study examined whether variations in brain development between kindergarten and Grade 3 predicted individual differences in reading ability at Grade 3. Structural MRI measurements indicated that increases in the volume of two left temporo-parietal white matter clusters are unique predictors of reading outcomes above and beyond family history, socioeconomic status, and cognitive and preliteracy measures at baseline. Using diffusion MRI, we identified the left arcuate fasciculus and superior corona radiata as key fibers within the two clusters. Bias-free regression analyses using regions of interest from prior literature revealed that volume changes in temporo-parietal white matter, together with preliteracy measures, predicted 56% of the variance in reading outcomes. Our findings demonstrate the important contribution of developmental differences in areas of left dorsal white matter, often implicated in phonological processing, as a sensitive early biomarker for later reading abilities, and by extension, reading difficulties. PMID:25212581

  14. Aerobic fitness is associated with greater white matter integrity in children

    PubMed Central

    Chaddock-Heyman, Laura; Erickson, Kirk I.; Holtrop, Joseph L.; Voss, Michelle W.; Pontifex, Matthew B.; Raine, Lauren B.; Hillman, Charles H.; Kramer, Arthur F.

    2014-01-01

    Aerobic fitness has been found to play a positive role in brain and cognitive health of children. Yet, many of the neural biomarkers related to aerobic fitness remain unknown. Here, using diffusion tensor imaging, we demonstrated that higher aerobic fitness was related to greater estimates of white matter microstructure in children. Higher fit 9- and 10-year-old children showed greater fractional anisotropy (FA) in sections of the corpus callosum, corona radiata, and superior longitudinal fasciculus, compared to lower fit children. The FA effects were primarily characterized by aerobic fitness differences in radial diffusivity, thereby raising the possibility that estimates of myelination may vary as a function of individual differences in fitness during childhood. White matter structure may be another potential neural mechanism of aerobic fitness that assists in efficient communication between gray matter regions as well as the integration of regions into networks. PMID:25191243

  15. [Internuclear ophthalmoplegia--causes, symptoms and management].

    PubMed

    Obuchowska, Iwona; Mariak, Zofia

    2009-01-01

    Internuclear ophthalmoplegia (INO) is a disorder of eye movements caused by a lesion in an area of the brain called the medial longitudinal fasciculus (MLF). The most common causes of INO are multiple sclerosis and brainstem infarction. Other causes include head trauma, brainstem and fourth ventricular tumors, Arnold-Chiari malformation, infection, hydrocephalus, and lupus erythematosus. Internuclear ophthalmoplegia is clinically characterized by total or partial failure to adduct one eye in lateral gaze and a monocular nystagmus of the abducting eye. It may be unilateral and bilateral. The method of choice for diagnostic imaging of MLF lesion in patients with INO is magnetic resonance. In this article authors present current opinion about pathogenesis, clinical symptoms, and management in patients with inter nuclear ophthalmoplegia. PMID:19673451

  16. Wall-eyed bilateral internuclear ophthalmoplegia in a patient with progressive supranuclear palsy.

    PubMed

    Ushio, Munetaka; Iwasaki, Shinichi; Chihara, Yasuhiro; Murofushi, Toshihisa

    2008-06-01

    Wall-eyed bilateral internuclear ophthalmoplegia (WEBINO) is a rare disorder consisting of a bilateral adduction deficit and primary gaze position exotropia. Associated with bilateral medial longitudinal fasciculus lesions, it has been mostly reported in patients with multiple sclerosis and brainstem stroke. A 72-year-old man with characteristic clinical features of progressive supranuclear palsy (PSP) later developed WEBINO. Brain MRI revealed atrophy of the midbrain tegmentum. Caloric irrigation revealed intact horizontal eye movements in both eyes. We believe this to be the first report of WEBINO in PSP. The preservation of vestibulo-ocular horizontal eye movements supports the notion that the WEBINO in this condition was caused by a supranuclear rather than a nuclear lesion and suggests the possibility that even in other causes of WEBINO, the lesion is supranuclear and not in the medial rectus subnucleus as is often suggested. PMID:18562838

  17. One-and-a-half syndrome--two cases.

    PubMed

    Ilniczky, Sándor; Kamondi, Anita; Várallyay, György; Gaal, Barbara; Palásti, Agnes; Gulyás, Szilvia; Szirmai, Imre

    2007-11-30

    One-and-a-half syndrome is characterized by combination of the clinical features of unilateral horizontal gaze palsy and internuclear ophthalmoplegia. The common symptoms are double vision and oscillopsia. The lesion is located in the paramedian pontine reticular formation, involving the centre of horizontal gaze and medial longitudinal fasciculus. More extensive brainstem damage may result in additional neurological signs. The most frequent underlying diseases are vascular insults, multiple sclerosis, and brainstem tumor. We present two cases of one-and-a-half syndrome. Both patients had lacunar infarction in the paramedian pontine tegmentum, revealed by MRI. The first patient had isolated eye movement disorder, while the second had additional nuclear-type facial paresis. In the first case brainstem evoked potentials indicated brainstem damage, in the second patient it was normal. Ocular symptoms improved within some days in both patients. PMID:18198796

  18. Brain changes within the visuo-spatial attentional network in posterior cortical atrophy.

    PubMed

    Cerami, Chiara; Crespi, Chiara; Della Rosa, Pasquale Anthony; Dodich, Alessandra; Marcone, Alessandra; Magnani, Giuseppe; Coppi, Elisabetta; Falini, Andrea; Cappa, Stefano F; Perani, Daniela

    2015-01-01

    Posterior cortical atrophy (PCA) is characterized by basic visual and high order visual-spatial dysfunctions. In this study, we investigated long-distance deafferentation processes within the frontal-parietal-occipital network in ten PCA patients using a MRI-PET combined approach. Objective voxel-based [18F]FDG-PET imaging measured metabolic changes in single patients. Comprehensive investigation of diffusion tensor imaging (DTI) metrics and grey-matter density with voxel-based morphometry were obtained in a subgroup of 6 patients. Fractional anisotropy in the superior longitudinal fasciculus correlated with the PET metabolic changes within the inferior parietal and frontal eye field regions. [18F]FDG-PET analysis showed in each PCA case the typical bilateral hypometabolic pattern, involving posterior temporal, parietal, and occipital cortex, with additional hypometabolic foci in the frontal eye fields. Voxel-based morphometry showed right-sided atrophy in the parieto-occipital cortex, as well as a limited temporal involvement. DTI revealed extensive degeneration of the major anterior-posterior connecting fiber bundles and of commissural frontal lobe tracts. Microstructural measures in the superior longitudinal fasciculus were correlated with the PET metabolic changes within the inferior parietal and frontal eye field regions. Our results confirmed the predominant occipital-temporal and occipital-parietal degeneration in PCA patients. [18F]FDG-PET and DTI-MRI combined approaches revealed neurodegeneration effects well beyond the classical posterior cortical involvement, most likely as a consequence of deafferentation processes within the occipital-parietal-frontal network that could be at the basis of visuo-perceptual, visuo-spatial integration and attention deficits in PCA. PMID:25114070

  19. Growth changes of the collagen content and architecture in the pectoralis and iliotibialis lateralis muscles of cockerels.

    PubMed

    Nakamura, Y N; Iwamoto, H; Shiba, N; Miyachi, H; Tabata, S; Nishimura, S

    2004-12-01

    1. Growth changes of the collagen content and architecture in the pectoralis (PT) and iliotibialis lateralis (ITL) muscles were examined using cockerels from 1 to 14 weeks of age. 2. Total collagen content in PT muscle showed little change, but in ITL muscle reached a maximum at 5 weeks and thereafter decreased slightly until 14 weeks. The collagen content was markedly larger in ITL muscle after 5 weeks. Pyridinoline content of collagen increased abruptly from 5 to 14 weeks in both muscles, but no difference between muscle types was detected. 3. The cell size of the endomysial honeycombs increased with the development of myofibres, and the mesh size of the perimysium around the honeycombs enlarged. 4. In both muscles endomysia were an incomplete network of collagen fibrils with many foramina at one week, became a very thin membrane of felt-like fabric in 2 to 5 weeks and thereafter increased in thickness until 11 to 14 weeks. 5. Perimysial width around the secondary fasciculus differed between the muscle types after 5 weeks. In the wider perimysium of ITL muscle, the collagen fibres increased in number and size to make a stack of collagen bands around the fasciculus. In the narrower perimysium of PT muscle, a few platelets of collagen fibres also developed. 6. The perimysial collagen fibre at 1 to 2 weeks had a smooth surface and appeared to be composed of fine collagen fibrils. The fibre at 11 to 14 weeks showed a rugged surface and was composed of coarser collagen bundles that combined with each other into a net-like configuration with very slim meshes. 7. Our results showed that the collagenous components of chicken intramuscular connective tissue changed markedly during the early period of muscle growth in distribution, architecture and quality but with little difference in quantity. PMID:15697014

  20. Sequential relationships between grey matter and white matter atrophy and brain metabolic abnormalities in early Alzheimer's disease

    PubMed Central

    Villain, Nicolas; Fouquet, Marine; Baron, Jean-Claude; Mézenge, Florence; Landeau, Brigitte; De La Sayette, Vincent; Viader, Fausto; Eustache, Francis; Desgranges, Béatrice; Chételat, Gaël

    2010-01-01

    Hippocampal atrophy, posterior cingulate and frontal glucose hypometabolism, and white-matter tract disruption are well-described early macroscopic events in Alzheimer’s disease. The relationships between these three types of alterations have been documented in previous studies, but their chronology still remains to be established. The present study used multi-modal Fluorodeoxyglucose - Positron Emission Tomography and Magnetic Resonance Imaging longitudinal data to address this question in patients with amnestic Mild Cognitive Impairment. We found unidirectional, specific sequential relationships between: i) baseline hippocampal atrophy and both cingulum bundle (r=0.70; p=3.10−3) and uncinate fasciculus (r=0.75; p=7.10−4) rate of atrophy; ii) baseline cingulum bundle atrophy and rate of decline of posterior (r=0.72; p=2.10−3) and anterior (r=0.74; p=1.10−3) cingulate metabolism; and iii) baseline uncinate white matter atrophy and subgenual metabolism rate of change (r=0.65; p=6.10−3). Baseline local grey matter atrophy was not found to contribute to hypometabolism progression within the posterior and anterior cingulate as well as subgenual cortices. These findings suggest that hippocampal atrophy progressively leads to disruption of the cingulum bundle and uncinate fasciculus, which in turn leads to glucose hypometabolism of the cingulate and subgenual cortices, respectively. This study reinforces the relevance of remote mechanisms above local interactions to account for the patterns of brain alteration observed in amnestic Mild Cognitive Impairment, and provides new avenues to assess the sequence of events in complex diseases characterized by multiple manifestations. PMID:20688814

  1. Influence of the fragile X mental retardation (FMR1) gene on the brain and working memory in men with normal FMR1 alleles

    PubMed Central

    Wang, Jun Yi; Hessl, David; Iwahashi, Christine; Cheung, Katherine; Schneider, Andrea; Hagerman, Randi J.; Hagerman, Paul J.; Rivera, Susan M.

    2012-01-01

    The fragile X mental retardation 1 (FMR1) gene plays an important role in the development and maintenance of neuronal circuits that are essential for cognitive functioning. We explored the functional linkage(s) among lymphocytic FMR1 gene expression, brain structure, and working memory in healthy adult males. We acquired T1-weighted and diffusion tensor imaging from 34 males (18–80 years, mean ± SD = 43.6 ± 18.4 years) with normal FMR1 alleles and performed genetic and working memory assessments. Brain measurements were obtained from fiber tracts important for working memory (i.e. the arcuate fasciculus, anterior cingulum bundle, inferior longitudinal fasciculus, and the genu and anterior body of the corpus callosum), individual voxels, and whole brain. Both FMR1 mRNA and protein (FMRP) levels exhibited significant associations with brain measurements, with FMRP correlating positively with gray matter volume and white matter structural organization, and FMR1 mRNA negatively with white matter structural organization. The correlation was widespread, impacting rostral white matter and 2 working-memory fiber tracts for FMRP, and all cerebral white matter areas except fornix and cerebellar peduncles and all 4 fiber tracts for FMR1 mRNA. In addition, the levels of FMR1 mRNA as well as the fiber tracts demonstrated significant correlation with working memory performance. While FMR1 mRNA exhibited negative correlation with working memory, fiber tract structural organization showed positive correlation. These findings suggest that the FMR1 gene is a genetic factor in common for both working memory and the brain structure, and has implications for our understanding of the transmission of intelligence and brain structure. PMID:23063447

  2. The architecture of the chess player's brain.

    PubMed

    Hänggi, Jürgen; Brütsch, Karin; Siegel, Adrian M; Jäncke, Lutz

    2014-09-01

    The game of chess can be seen as a typical example for an expertise task requiring domain-specific training and experience. Despite intensive behavioural studies the neural underpinnings of chess performance and expertise are not entirely understood. A few functional neuroimaging studies have shown that expert chess players recruit different psychological functions and activate different brain areas while they are engaged in chess-related activities. Based on this functional literature, we predicted to find morphological differences in a network comprised by parietal and frontal areas and especially the occipito-temporal junction (OTJ), fusiform gyrus, and caudate nucleus. Twenty expert chess players and 20 control subjects were investigated using voxel-based and surface-based morphometry as well as diffusion tensor imaging. Grey matter volume and cortical thickness were reduced in chess players compared with those of control men in the OTJ and precunei. The volumes of both caudate nuclei were not different between groups, but correlated inversely with the years of chess playing experience. Mean diffusivity was increased in chess players compared with that of controls in the left superior longitudinal fasciculus and the Elo score (a chess tournament ranking) was inversely related to mean diffusivity within the right superior longitudinal fasciculus. To the best of our knowledge we showed for the first time that there are specific differences in grey and white matter morphology between chess players and control subjects in brain regions associated with cognitive functions important for playing chess. Whether these anatomical alterations are the cause or consequence of the intensive and long-term chess training and practice remains to be shown in future studies. PMID:25065494

  3. Intraoperative mapping of the subcortical language pathways using direct stimulations. An anatomo-functional study.

    PubMed

    Duffau, Hugues; Capelle, Laurent; Sichez, Nicole; Denvil, Dominique; Lopes, Manuel; Sichez, Jean-Pierre; Bitar, Ahmad; Fohanno, Denis

    2002-01-01

    Functional neuroimaging has improved pre-planning of surgery in eloquent cortical areas, but remains unable to map white matter. Thus, tumour resection in functional subcortical regions still presents a high risk of sequelae. The authors successfully used intraoperative electrical stimulations to perform subcortical language pathway mapping in order to avoid postoperative definitive deficit, and correlated these functional findings with the anatomical location of the eloquent bundles detected using postoperative MRI. At the same time, this also improved knowledge of fibre connectivity. Thirty patients harbouring a cortico-subcortical low-grade glioma in the left dominant hemisphere were operated on whilst awake using intraoperative electrical functional mapping during surgical resection. Language cortical sites and subcortical pathways were clearly identified and preserved in the 30 cases. The anatomo-functional correlations between data obtained using intraoperative subcortical mapping and postoperative MRI revealed the existence in all patients of common pathways which seem essential to language. This was shown by inducing reproducible speech disturbances during stimulations as follows: the subcallosal fasciculus (initiation disorders), the periventricular white matter (dysarthria), the arcuate fasciculus and the insular connections (anomia). Clinically, all patients except three presented a transient postoperative dysphasia, which resolved within 3 months. On control MRI, 14 resections were total and 16 subtotal due to infiltration of functional bundles described above. It is recommended that the combination of the techniques as described could prove ideal for future non-invasive reliable subcortical mapping both in healthy volunteers and in patients harbouring a (cortico)subcortical lesion in order to optimize surgical pre-planning. PMID:11834604

  4. Sex differences in white matter integrity in youths with attention-deficit/hyperactivity disorder: a pilot study

    PubMed Central

    King, Jace B.; Yurgelun-Todd, Deborah; Stoeckel, Amanda; DiMuzio, Jennifer M.; Lopez-Larson, Melissa P.

    2015-01-01

    Widespread disparities in white matter (WM) microstructure and organization have been found in adolescents with attention-deficit/hyperactivity disorder (ADHD); however, little is known about the role sex plays in these differences. The present diffusion tensor imaging (DTI) study performed whole-brain, tract-based, voxel-wise, and region of interest (ROI) analyses to investigate WM microstructure differences between ADHD and healthy control (HC) adolescents to examine the impact of sex on measures of fractional anisotropy (FA). Eighteen adolescents with ADHD and 24 HC were included in this study. All participants received a 64-direction DTI scan on a 3 Tesla Siemens scanner. FSL's TBSS was used to perform whole-brain, tract-based, voxel-wise analyses. Tracts demonstrating significant sex-by-diagnosis interactions were further evaluated using univariate analyses performed on mean FA data that were extracted from ROIs using the Johns Hopkins University WM tractography atlas. TBSS analyses between diagnostic groups revealed significantly increased FA in HC relative to ADHD in the bilateral superior longitudinal fasciculus (SLF), forceps major, left cingulum, and bilateral callosal regions. In addition, both TBSS and separate ROI analyses revealed significant sex-by-diagnosis interactions for the corticospinal tract (CST), inferior longitudinal fasciculus (ILF) and SLF. In the HC group, FA was increased in males relative to females for all analyses. In WM regions demonstrating a significant sex-by-diagnosis, FA was increased in females relative to males in the ADHD group. Our findings suggest that WM microstructure in several major WM tracts differs between males and females with ADHD. These differences in WM microstructure may account for some of the differences in ADHD subtypes and comorbidities seen between the sexes. Additional studies in ADHD, examining sex differences in phenotypic expression, treatment response and brain network trajectories are warranted. PMID:26190967

  5. Changes in descending motor pathway connectivity after corticospinal tract lesion in macaque monkey

    PubMed Central

    Zaaimi, Boubker; Edgley, Steve A.; Soteropoulos, Demetris S.

    2012-01-01

    Damage to the corticospinal tract is a leading cause of motor disability, for example in stroke or spinal cord injury. Some function usually recovers, but whether plasticity of undamaged ipsilaterally descending corticospinal axons and/or brainstem pathways such as the reticulospinal tract contributes to recovery is unknown. Here, we examined the connectivity in these pathways to motor neurons after recovery from corticospinal lesions. Extensive unilateral lesions of the medullary corticospinal fibres in the pyramidal tract were made in three adult macaque monkeys. After an initial contralateral flaccid paralysis, motor function rapidly recovered, after which all animals were capable of climbing and supporting their weight by gripping the cage bars with the contralesional hand. In one animal where experimental testing was carried out, there was (as expected) no recovery of fine independent finger movements. Around 6 months post-lesion, intracellular recordings were made from 167 motor neurons innervating hand and forearm muscles. Synaptic responses evoked by stimulating the unlesioned ipsilateral pyramidal tract and the medial longitudinal fasciculus were recorded and compared with control responses in 207 motor neurons from six unlesioned animals. Input from the ipsilateral pyramidal tract was rare and weak in both lesioned and control animals, suggesting a limited role for this pathway in functional recovery. In contrast, mono- and disynaptic excitatory post-synaptic potentials elicited from the medial longitudinal fasciculus significantly increased in average size after recovery, but only in motor neurons innervating forearm flexor and intrinsic hand muscles, not in forearm extensor motor neurons. We conclude that reticulospinal systems sub-serve some of the functional recovery after corticospinal lesions. The imbalanced strengthening of connections to flexor, but not extensor, motor neurons mirrors the extensor weakness and flexor spasm which in neurological experience is a common limitation to recovery in stroke survivors. PMID:22581799

  6. Sensory-to-motor integration during auditory repetition: a combined fMRI and lesion study

    PubMed Central

    Parker Jones, ‘?iwi; Prejawa, Susan; Hope, Thomas M. H.; Oberhuber, Marion; Seghier, Mohamed L.; Leff, Alex P.; Green, David W.; Price, Cathy J.

    2014-01-01

    The aim of this paper was to investigate the neurological underpinnings of auditory-to-motor translation during auditory repetition of unfamiliar pseudowords. We tested two different hypotheses. First we used functional magnetic resonance imaging in 25 healthy subjects to determine whether a functionally defined area in the left temporo-parietal junction (TPJ), referred to as Sylvian-parietal-temporal region (Spt), reflected the demands on auditory-to-motor integration during the repetition of pseudowords relative to a semantically mediated nonverbal sound-naming task. The experiment also allowed us to test alternative accounts of Spt function, namely that Spt is involved in subvocal articulation or auditory processing that can be driven either bottom-up or top-down. The results did not provide convincing evidence that activation increased in either Spt or any other cortical area when non-semantic auditory inputs were being translated into motor outputs. Instead, the results were most consistent with Spt responding to bottom up or top down auditory processing, independent of the demands on auditory-to-motor integration. Second, we investigated the lesion sites in eight patients who had selective difficulties repeating heard words but with preserved word comprehension, picture naming and verbal fluency (i.e., conduction aphasia). All eight patients had white-matter tract damage in the vicinity of the arcuate fasciculus and only one of the eight patients had additional damage to the Spt region, defined functionally in our fMRI data. Our results are therefore most consistent with the neurological tradition that emphasizes the importance of the arcuate fasciculus in the non-semantic integration of auditory and motor speech processing. PMID:24550807

  7. White matter pathway supporting phonological encoding in speech production: a multi-modal imaging study of brain damage patients.

    PubMed

    Han, Zaizhu; Ma, Yujun; Gong, Gaolang; Huang, Ruiwang; Song, Luping; Bi, Yanchao

    2016-01-01

    In speech production, an important step before motor programming is the retrieval and encoding of the phonological elements of target words. It has been proposed that phonological encoding is supported by multiple regions in the left frontal, temporal and parietal regions and their underlying white matter, especially the left arcuate fasciculus (AF) or superior longitudinal fasciculus (SLF). It is unclear, however, whether the effects of AF/SLF are indeed related to phonological encoding for output and whether there are other white matter tracts that also contribute to this process. We comprehensively investigated the anatomical connectivity supporting phonological encoding in production by studying the relationship between the integrity of all major white matter tracts across the entire brain and phonological encoding deficits in a group of 69 patients with brain damage. The integrity of each white matter tract was measured both by the percentage of damaged voxels (structural imaging) and the mean fractional anisotropy value (diffusion tensor imaging). The phonological encoding deficits were assessed by various measures in two oral production tasks that involve phonological encoding: the percentage of nonword (phonological) errors in oral picture naming and the accuracy of word reading aloud with word comprehension ability regressed out. We found that the integrity of the left SLF in both the structural and diffusion tensor imaging measures consistently predicted the severity of phonological encoding impairment in the two phonological production tasks. Such effects of the left SLF on phonological production remained significant when a range of potential confounding factors were considered through partial correlation, including total lesion volume, demographic factors, lesions on phonological-relevant grey matter regions, or effects originating from the phonological perception or semantic processes. Our results therefore conclusively demonstrate the central role of the left SLF in phonological encoding in speech production. PMID:25359657

  8. Primary and secondary alterations of white matter connectivity in schizophrenia: A study on first-episode and chronic patients using whole-brain tractography-based analysis.

    PubMed

    Wu, Chen-Hao; Hwang, Tzung-Jeng; Chen, Yu-Jen; Hsu, Yung-Chin; Lo, Yu-Chun; Liu, Chih-Min; Hwu, Hai-Gwo; Liu, Chen-Chung; Hsieh, Ming H; Chien, Yi-Ling; Chen, Chung-Ming; Isaac Tseng, Wen-Yih

    2015-12-01

    Schizophrenia is a debilitating mental disorder that is associated with an impaired connection of cerebral white matter. Studies on patients with chronic and first-episode schizophrenia have found widespread white matter abnormalities. However, it is unclear whether the altered connections are inherent in or secondary to the disease. Here, we sought to identify white matter tracts with altered connections and to distinguish primary or secondary alterations among 74 fiber tracts across the whole brain using an automatic tractography-based analysis method. Thirty-one chronic, 25 first-episode patients with schizophrenia and 31 healthy controls were recruited to receive diffusion spectrum magnetic resonance imaging at 3T. Seven tracts were found to exhibit significant differences between the groups; they included the right arcuate fasciculus, bilateral fornices, left superior longitudinal fasciculus I, and fibers of the corpus callosum to the bilateral dorsolateral prefrontal cortices (DLPFC), bilateral temporal poles, and bilateral hippocampi. Post-hoc between-group analyses revealed that the connection of the callosal fibers to the bilateral DLPFC was significantly decreased in chronic patients but not in first-episode patients. In a stepwise regression analysis, the decline of the tract connection was significantly predicted by the duration of illness. In contrast, the remaining six tracts showed significant alterations in both first-episode and chronic patients and did not associate with clinical variables. In conclusion, reduced white matter connectivity of the callosal fibers to the bilateral DLPFC may be a secondary change that degrades progressively in the chronic stage, whereas alterations in the other six tracts may be inherent in the disease. PMID:26443482

  9. Segregation of anterior temporal regions critical for retrieving names of unique and non-unique entities reflects underlying long-range connectivity.

    PubMed

    Mehta, Sonya; Inoue, Kayo; Rudrauf, David; Damasio, Hanna; Tranel, Daniel; Grabowski, Thomas

    2016-02-01

    Lesion-deficit studies support the hypothesis that the left anterior temporal lobe (ATL) plays a critical role in retrieving names of concrete entities. They further suggest that different regions of the left ATL process different conceptual categories. Here we test the specificity of these relationships and whether the anatomical segregation is related to the underlying organization of white matter connections. We reanalyzed data from a previous lesion study of naming and recognition across five categories of concrete entities. In voxelwise logistic regressions of lesion-deficit associations, we formally incorporated measures of disconnection of long-range association fiber tracts (FTs) and covaried for recognition and non-category-specific naming deficits. We also performed fiber tractwise analyses to assess whether damage to specific FTs was preferentially associated with category-selective naming deficits. Damage to the basolateral ATL was associated with naming deficits for both unique (famous faces) and non-unique entities, whereas the damage to the temporal pole was associated with naming deficits for unique entities only. This segregation pattern remained after accounting for comorbid recognition deficits or naming deficits in other categories. The tractwise analyses showed that damage to the uncinate fasciculus (UNC) was associated with naming impairments for unique entities, while damage to the inferior longitudinal fasciculus (ILF) was associated with naming impairments for non-unique entities. Covarying for FT transection in voxelwise analyses rendered the cortical association for unique entities more focal. These results are consistent with the partial segregation of brain system support for name retrieval of unique and non-unique entities at both the level of cortical components and underlying white matter fiber bundles. Our study reconciles theoretic accounts of the functional organization of the left ATL by revealing both category-related processing and semantic hub sectors. PMID:26707082

  10. Distinct types of white matter changes are observed after anterior temporal lobectomy in epilepsy.

    PubMed

    Pustina, Dorian; Doucet, Gaelle; Evans, James; Sharan, Ashwini; Sperling, Michael; Skidmore, Christopher; Tracy, Joseph

    2014-01-01

    Anterior temporal lobectomy (ATL) is commonly adopted to control medically intractable temporal lobe epilepsy (TLE). Depending on the side of resection, the degree to which Wallerian degeneration and adaptive plasticity occur after ATL has important implications for understanding cognitive and clinical outcome. We obtained diffusion tensor imaging from 24 TLE patients (12 left) before and after surgery, and 12 matched controls at comparable time intervals. Voxel-based analyses were performed on fractional anisotropy (FA) before and after surgery. Areas with postoperative FA increase were further investigated to distinguish between genuine plasticity and processes related to the degeneration of crossing fibers. Before surgery, both patient groups showed bilateral reduced FA in numerous tracts, but left TLE patients showed more extensive effects, including language tracts in the contralateral hemisphere (superior longitudinal fasciculus and uncinate). After surgery, FA decreased ipsilaterally in both ATL groups, affecting the fornix, uncinate, stria terminalis, and corpus callosum. FA increased ipsilaterally along the superior corona radiata in both left and right ATL groups, exceeding normal FA values. In these clusters, the mode of anisotropy increased as well, confirming fiber degeneration in an area with crossing fibers. In left ATL patients, pre-existing low FA values in right superior longitudinal and uncinate fasciculi normalized after surgery, while MO values did not change. Preoperative verbal fluency correlated with FA values in all areas that later increased FA in left TLE patients, but postoperative verbal fluency correlated only with FA of the right superior longitudinal fasciculus. Our results demonstrate that genuine reorganization occurs in non-dominant language tracts after dominant hemisphere resection, a process that may help implement the inter-hemispheric shift of language activation found in fMRI studies. The results indicate that left TLE patients, despite showing more initial white matter damage, have the potential for greater adaptive changes postoperatively than right TLE patients. PMID:25089698

  11. White matter fiber compromise contributes differentially to attention and emotion processing impairment in alcoholism, HIV-infection, and their comorbidity

    PubMed Central

    Schulte, T.; Müller-Oehring, E.M.; Sullivan, E.V.; Pfefferbaum, A.

    2012-01-01

    Alcoholism (ALC) and HIV-1 infection (HIV) each affects emotional and attentional processes and integrity of brain white matter fibers likely contributing to functional compromise. The highly prevalent ALC+HIV comorbidity may exacerbate compromise. We used diffusion tensor imaging (DTI) and an emotional Stroop Match-to-Sample task in 19 ALC, 16 HIV, 15 ALC+HIV, and 15 control participants to investigate whether disruption of fiber system integrity accounts for compromised attentional and emotional processing. The task required matching a cue color to that of an emotional word with faces appearing between the color cue and the Stroop word in half of the trials. Nonmatched cue-word color pairs assessed selective attention, and face-word pairs assessed emotion. Relative to controls, DTI-based fiber tracking revealed lower inferior longitudinal fasciculus (ilf) integrity in HIV and ALC+HIV and lower uncinate fasciculus (uf) integrity in all three patient groups. Controls exhibited Stroop effects to positive face-word emotion, and greater interference was related to greater callosal, cingulum and ilf integrity. By contrast, HIV showed greater interference from negative Stroop words during color-nonmatch trials, correlating with greater uf compromise. For face trials, ALC and ALC+HIV showed greater Stroop-word interference, correlating with lower cingulate and callosal integrity. Thus, in HIV, conflict resolution was diminished when challenging conditions usurped resources needed to manage interference from negative emotion and to disengage attention from wrongly cued colors (nonmatch). In ALC and ALC+HIV, poorer callosal integrity was related to enhanced emotional interference suggesting curtailed interhemispheric exchange needed between preferentially right-hemispheric emotion and left-hemispheric Stroop-word functions. PMID:22960416

  12. Sensory-to-motor integration during auditory repetition: a combined fMRI and lesion study.

    PubMed

    Parker Jones, '?iwi; Prejawa, Susan; Hope, Thomas M H; Oberhuber, Marion; Seghier, Mohamed L; Leff, Alex P; Green, David W; Price, Cathy J

    2014-01-01

    The aim of this paper was to investigate the neurological underpinnings of auditory-to-motor translation during auditory repetition of unfamiliar pseudowords. We tested two different hypotheses. First we used functional magnetic resonance imaging in 25 healthy subjects to determine whether a functionally defined area in the left temporo-parietal junction (TPJ), referred to as Sylvian-parietal-temporal region (Spt), reflected the demands on auditory-to-motor integration during the repetition of pseudowords relative to a semantically mediated nonverbal sound-naming task. The experiment also allowed us to test alternative accounts of Spt function, namely that Spt is involved in subvocal articulation or auditory processing that can be driven either bottom-up or top-down. The results did not provide convincing evidence that activation increased in either Spt or any other cortical area when non-semantic auditory inputs were being translated into motor outputs. Instead, the results were most consistent with Spt responding to bottom up or top down auditory processing, independent of the demands on auditory-to-motor integration. Second, we investigated the lesion sites in eight patients who had selective difficulties repeating heard words but with preserved word comprehension, picture naming and verbal fluency (i.e., conduction aphasia). All eight patients had white-matter tract damage in the vicinity of the arcuate fasciculus and only one of the eight patients had additional damage to the Spt region, defined functionally in our fMRI data. Our results are therefore most consistent with the neurological tradition that emphasizes the importance of the arcuate fasciculus in the non-semantic integration of auditory and motor speech processing. PMID:24550807

  13. Frontotemporal neural systems supporting semantic processing in Alzheimer's disease.

    PubMed

    Peelle, Jonathan E; Powers, John; Cook, Philip A; Smith, Edward E; Grossman, Murray

    2014-03-01

    We hypothesized that semantic memory for object concepts involves both representations of visual feature knowledge in modality-specific association cortex and heteromodal regions that are important for integrating and organizing this semantic knowledge so that it can be used in a flexible, contextually appropriate manner. We examined this hypothesis in an fMRI study of mild Alzheimer's disease (AD). Participants were presented with pairs of printed words and asked whether the words matched on a given visual-perceptual feature (e.g., guitar, violin: SHAPE). The stimuli probed natural kinds and manufactured objects, and the judgments involved shape or color. We found activation of bilateral ventral temporal cortex and left dorsolateral prefrontal cortex during semantic judgments, with AD patients showing less activation of these regions than healthy seniors. Moreover, AD patients showed less ventral temporal activation than did healthy seniors for manufactured objects, but not for natural kinds. We also used diffusion-weighted MRI of white matter to examine fractional anisotropy (FA). Patients with AD showed significantly reduced FA in the superior longitudinal fasciculus and inferior frontal-occipital fasciculus, which carry projections linking temporal and frontal regions of this semantic network. Our results are consistent with the hypothesis that semantic memory is supported in part by a large-scale neural network involving modality-specific association cortex, heteromodal association cortex, and projections between these regions. The semantic deficit in AD thus arises from gray matter disease that affects the representation of feature knowledge and processing its content, as well as white matter disease that interrupts the integrated functioning of this large-scale network. PMID:24425352

  14. Structural and Diffusion Property Alterations in Unaffected Siblings of Patients with Obsessive-Compulsive Disorder

    PubMed Central

    Shi, Changzheng; Miao, Guodong; Yang, Qiong; Gao, Wei; Wolff, Jason J.; Chan, Raymond C. K.; Shen, Dinggang

    2014-01-01

    Disrupted white matter integrity and abnormal cortical thickness are widely reported in the pathophysiology of obsessive-compulsive disorder (OCD). However, the relationship between alterations in white matter connectivity and cortical thickness in OCD is unclear. In addition, the heritability of this relationship is poorly understood. To investigate the relationship of white matter microstructure with cortical thickness, we measure fractional anisotropy (FA) of white matter in 30 OCD patients, 19 unaffected siblings and 30 matched healthy controls. Then, we take those regions of significantly altered FA in OCD patients compared with healthy controls to perform fiber tracking. Next, we calculate the fiber quantity in the same tracts. Lastly, we compare cortical thickness in the target regions of those tracts. Patients with OCD exhibited decreased FA in cingulum, arcuate fibers near the superior parietal lobule, inferior longitudinal fasciculus near the right superior temporal gyrus and uncinate fasciculus. Siblings showed reduced FA in arcuate fibers near the superior parietal lobule and anterior limb of internal capsule. Significant reductions in both fiber quantities and cortical thickness in OCD patients and their unaffected siblings were also observed in the projected brain areas when using the arcuate fibers near the left superior parietal lobule as the starting points. Reduced FA in the left superior parietal lobule was observed not only in patients with OCD but also in their unaffected siblings. Originated from the superior parietal lobule, the number of fibers was also found to be decreased and the corresponding cortical regions were thinner relative to controls. The linkage between disrupted white matter integrity and the abnormal cortical thickness may be a vulnerability marker for OCD. PMID:24489665

  15. A multimodal neuroimaging study of a case of crossed nonfluent/agrammatic primary progressive aphasia.

    PubMed

    Spinelli, Edoardo G; Caso, Francesca; Agosta, Federica; Gambina, Giuseppe; Magnani, Giuseppe; Canu, Elisa; Blasi, Valeria; Perani, Daniela; Comi, Giancarlo; Falini, Andrea; Gorno-Tempini, Maria Luisa; Filippi, Massimo

    2015-10-01

    Crossed aphasia has been reported mainly as post-stroke aphasia resulting from brain damage ipsilateral to the dominant right hand. Here, we described a case of a crossed nonfluent/agrammatic primary progressive aphasia (nfvPPA), who developed a corticobasal syndrome (CBS). We collected clinical, cognitive, and neuroimaging data for four consecutive years from a 55-year-old right-handed lady (JV) presenting with speech disturbances. 18-fluorodeoxyglucose positron emission tomography ((18)F-FDG PET) and DaT-scan with (123)I-Ioflupane were obtained. Functional MRI (fMRI) during a verb naming task was acquired to characterize patterns of language lateralization. Diffusion tensor MRI was used to evaluate white matter damage within the language network. At onset, JV presented with prominent speech output impairment and right frontal atrophy. After 3 years, language deficits worsened, with the occurrence of a mild agrammatism. The patient also developed a left-sided mild extrapyramidal bradykinetic-rigid syndrome. The clinical picture was suggestive of nfvPPA with mild left-sided extrapyramidal syndrome. At this time, voxel-wise SPM analyses of (18)F-FDG PET and structural MRI showed right greater than left frontal hypometabolism and damage, which included the Broca's area. DaT-scan showed a reduced uptake in the right striatum. FMRI during naming task demonstrated bilateral language activations, and tractography showed right superior longitudinal fasciculus (SLF) involvement. Over the following year, JV became mute and developed frank left-sided motor signs and symptoms, evolving into a CBS clinical picture. Brain atrophy worsened in frontal areas bilaterally, and extended to temporo-parietal regions, still with a right-sided asymmetry. Tractography showed an extension of damage to the left SLF and right inferior longitudinal fasciculus. We report a case of crossed nfvPPA followed longitudinally and studied with advanced neuroimaging techniques. The results highlight a complex interaction between individual premorbid developmental differences and the clinical phenotype. PMID:26194195

  16. Triphenyl phosphite and diisopropylphosphorofluoridate produce separate and distinct axonal degeneration patterns in the central nervous system of the rat.

    PubMed

    Lehning, E J; Tanaka, D; Bursian, S J

    1996-01-01

    This study compared the neurotoxic effects of triphenyl phosphite (TPP) in the rat with those seen after exposure to diisopropylphosphorofluoridate (DFP), a compound known to produce organophosphorus-induced delayed neurotoxicity (OPIDN). Animals received either three subcutaneous injections of TPP (1184 mg/kg body wt each dose) administered at 3-day intervals or a single subcutaneous injection of DFP (4 mg/kg body wt). TPP-induced clinical signs were initially observed 2 to 18 days after the last injection and included ataxia, flaccid paresis, stereotyped alternating side-to-side movements, and circling behavior. Axonal and terminal degeneration were present in the cerebellum, vestibular nuclear complex, cochlear nuclei, and superior and inferior colliculi. The subthalamic nucleus, substantia nigra, septal region, hypothalamus, thalamus, hippocampus, and cerebral cortex also contained degenerating axons and terminals. Degeneration was particularly evident in the sensorimotor cerebral cortex, mediodorsal, ventromedial, and medial geniculate thalamic nuclei and in the magnocellular preoptic and medial mammillary nuclei of the hypothalamus. Very light degeneration was present in the gracile fasciculus and nucleus. In contrast, rats injected with DFP showed moderate degeneration in the gracile fasciculus and nucleus but did not display degeneration in any other brain region. Injections of DFP did not produce delayed onset clinical signs. The results indicate that in the rat, different central nervous system cell groups are affected by these two organophosphorus compounds and that TPP affects nuclei and tracts at all levels of the neuraxis, including those associated with higher-order processing and cognitive functions. In addition, the distinct degeneration patterns produced by these two compounds support the view that TPP-induced neurotoxicity should not be considered as a type of OPIDN, but rather as a separate category of organophosphorus-induced neurotoxicity. PMID:8838646

  17. Reduced Fractional Anisotropy in the Visual Limbic Pathway of Young Adults Witnessing Domestic Violence in Childhood

    PubMed Central

    Choi, Jeewook; Jeong, Bumseok; Polcari, Ann; Rohan, Michael L.; Teicher, Martin H.

    2011-01-01

    Witnessing domestic violence (WDV) is a traumatic childhood experience associated with increased risk for depression, posttraumatic stress disorder and reduced IQ scores. Specific affects of WDV on brain development have not been assessed. We sought to ascertain whether WDV was associated with abnormalities in white matter (WM) tract integrity using diffusion tensor imaging (DTI). Twenty subjects who witnessed domestic violence (16F/ 4M, mean age 22.4±2.48 yrs) but were not physically or sexually abused were compared to 27 healthy controls (19F/ 8M, 21.9±1.97 yrs) without exposure to trauma or Axis I and II disorders. DTI images were acquired with a 3T Siemens Trio scanner. Group differences in fractional anisotropy (FA), covaried by age, gender, parental education, perceived financial sufficiency, IQ and degree of exposure to parental verbal aggression were assessed using tract-based spatial statistics (TBSS), which projects FA values onto an alignment-invariant fiber tract representation. FA values in the inferior longitudinal fasciculus of left lateral occipital lobe were significantly lower (p<0.05 corrected for multiple comparison) in the WDV group. FA values correlated inversely with ratings of depression, anxiety, somatization, ‘limbic irritability’ and neuropsychological measures of processing speed. Measures of radial but not axial diffusivity were affected suggesting alterations in myelination. Degree of FA reduction was associated with duration of witnessing interparental verbal aggression and with exposure between ages 7 – 13 years. The inferior longitudinal fasciculus connects occipital and temporal cortex and is the main component of the visual–limbic pathway that subserves emotional, learning and memory functions that are modality specific to vision. This finding is consistent with the hypothesis that exposure to childhood maltreatment is associated with alterations in fiber pathways that convey the adverse experience to frontal, temporal or limbic regions. PMID:21985907

  18. White matter tractography in early psychosis: clinical and neurocognitive associations

    PubMed Central

    Hatton, Sean N.; Lagopoulos, Jim; Hermens, Daniel F.; Hickie, Ian B.; Scott, Elizabeth; Bennett, Maxwell R.

    2014-01-01

    Background While many diffusion tensor imaging (DTI) investigations have noted disruptions to white matter integrity in individuals with chronic psychotic disorders, fewer studies have been conducted in young people at the early stages of disease onset. Using whole tract reconstruction techniques, the aim of this study was to identify the white matter pathology associated with the common clinical symptoms and executive function impairments observed in young people with psychosis. Methods We obtained MRI scans from young people with psychosis and healthy controls. Eighteen major white matter tracts were reconstructed to determine group differences in fractional anisotropy (FA), axial diffusivity (AD) and radial diffusivity (RD) and then were subsequently correlated with symptomatology and neurocognitive performance. Results Our study included 42 young people with psychosis (mean age 23 yr) and 45 healthy controls (mean age 25 yr). Compared with the control group, the psychosis group had reduced FA and AD in the left inferior longitudinal fasciculus (ILF) and forceps major indicative of axonal disorganization, reduction and/or loss. These changes were associated with worse overall psychiatric symptom severity, increases in positive and negative symptoms, and worse current levels of depression. The psychosis group also showed FA reductions in the left superior longitudinal fasciculus that were associated with impaired neurocognitive performance in attention and semantic fluency. Limitations Our analysis grouped 4 subcategories of psychosis together, and a larger follow-up study comparing affective and nonaffective psychoses is warranted. Conclusion Our findings suggest that impaired axonal coherence in the left ILF and forceps major underpin psychiatric symptoms in young people in the early stages of psychosis. PMID:25111788

  19. The relation between structural and functional connectivity depends on age and on task goals

    PubMed Central

    Ford, Jaclyn H.; Kensinger, Elizabeth A.

    2014-01-01

    The last decade has seen an increase in neuroimaging studies examining structural (i.e., structural integrity of white matter tracts) and functional connectivity (e.g., correlations in neural activity throughout the brain). Although structural and functional connectivity changes have often been measured independently, examining the relation between these two measures is critical to understanding the specific function of neural networks and the ways they may differ across tasks and individuals. The current study addressed this question by examining the effect of age (treated as a continuous variable) and emotional valence on the relation between functional and structural connectivity. As prior studies have suggested that prefrontal regions may guide and regulate emotional memory search via functional connections with the amygdala, the current analysis focused on functional connectivity between the left amygdala and the left prefrontal cortex, and structural integrity of the uncinate fasciculus, a white matter tract connecting prefrontal and temporal regions. Participants took part in a scanned retrieval task in which they recalled positive, negative, and neutral images associated with neutral titles. Aging was associated with a significant increase in the relation between measures of structural integrity (specifically, fractional anisotropy, or FA) along the uncinate fasciculus and functional connectivity between the left ventral prefrontal cortex and amygdala during positive event retrieval, but not negative or neutral retrieval. Notably, during negative event retrieval, age was linked to stronger structure-function relations between the amygdala and the dorsal anterior cingulate cortex, such that increased structural integrity predicted stronger negative functional connectivity in older adults only. These findings suggest that young and older adults may utilize a structural pathway to engage different retrieval and regulatory strategies, even when structural integrity along that pathway does not differ. PMID:24904351

  20. Apathy in Frontotemporal Degeneration: Neuroanatomical Evidence of Impaired Goal-directed Behavior

    PubMed Central

    Massimo, Lauren; Powers, John P.; Evans, Lois K.; McMillan, Corey T.; Rascovsky, Katya; Eslinger, Paul; Ersek, Mary; Irwin, David J.; Grossman, Murray

    2015-01-01

    Background: Apathy, the major manifestation of impaired goal-directed behavior (GDB), is the most common neuropsychiatric syndrome associated with behavioral variant frontotemporal degeneration (bvFTD). The behavioral and biological mechanisms of apathy, however, are not well understood. We hypothesized that GDB has multiple components—including at least initiation, planning and motivation—and that GDB is supported by a network of multiple frontal brain regions. In this study, we examined this hypothesis by evaluating the selective breakdown of GDB in bvFTD, and relating these deficits to gray matter (GM) atrophy and white matter (WM) integrity. Methods: Eighteen apathetic bvFTD participants and 17 healthy controls completed the Philadelphia Apathy Computerized Test (PACT). This test quantifies each of three components of GDB hypothesized to contribute to apathy. We then used regression analyses to relate PACT scores to GM atrophy and reduced white matter (WM) fractional anisotropy (FA) in bvFTD. Results: Compared to controls, bvFTD participants demonstrated significant impairments in each of the three hypothesized components of GDB that contribute to apathy. Regression analyses related each component to disease in specific GM structures and associated WM tracts. Poor initiation thus was related to GM atrophy in anterior cingulate and reduced FA in the cingulum. Planning impairment was related to GM atrophy in dorsolateral prefrontal cortex and reduced FA in superior longitudinal fasciculus. Poor motivation was related to GM atrophy in orbitofrontal cortex (OFC) and reduced FA in uncinate fasciculus (UNC). Conclusions: bvFTD patients have difficulty with initiation, planning and motivation components of GDB. These findings are consistent with the hypotheses that GDB encompasses at least three processes, that these are supported by a large-scale neural network within specific portions of the frontal lobe, and that degradation of any one of these prefrontal regions in bvFTD may contribute to apathy. PMID:26617508

  1. Rules Ventral Prefrontal Cortical Axons Use to Reach Their Targets: Implications for Diffusion Tensor Imaging Tractography and Deep Brain Stimulation for Psychiatric Illness

    PubMed Central

    Lehman, Julia F.; Greenberg, Benjamin D.; McIntyre, Cameron C.; Rasmussen, Steve A.; Haber, Suzanne N.

    2011-01-01

    The ventral prefrontal cortex (vPFC) is involved in reinforcement-based learning and is associated with depression, obsessive-compulsive disorder, and addiction. Neuroimaging is increasingly used to develop models of vPFC connections, to examine white matter (WM) integrity, and to target surgical interventions, including deep brain stimulation. We used primate (Macaca nemestrina/Macaca fascicularis) tracing studies and 3D reconstructions of WM tracts to delineate the rules vPFC projections follow to reach their targets. vPFC efferent axons travel through the uncinate fasciculus, connecting different vPFC regions and linking different functional regions. The uncinate fasciculus also is a conduit for vPFC fibers to reach other cortical bundles. Fibers in the internal capsule are organized according to destination. Thalamic fibers from each vPFC region travel dorsal to their brainstem fibers. The results show regional differences in the trajectories of fibers from different vPFC areas. Overall, the medial/lateral vPFC position dictates the route that fibers take to enter major WM tracts, as well as the position within specific tracts: axons from medial vPFC regions travel ventral to those from more lateral areas. This arrangement, coupled with dorsal/ventral organization of thalamic/brainstem fibers through the internal capsule, results in a complex mingling of thalamic and brainstem axons from different vPFC areas. Together, these data provide the foundation for dividing vPFC WM bundles into functional components and for predicting what is likely to be carried at different points through each bundle. These results also help determine the specific connections that are likely to be captured at different neurosurgical targets. PMID:21753016

  2. Depressive symptoms and white matter dysfunction in retired NFL players with concussion history

    PubMed Central

    Strain, Jeremy; Didehbani, Nyaz; Cullum, C. Munro; Mansinghani, Sethesh; Conover, Heather; Kraut, Michael A.; Womack, Kyle B.

    2013-01-01

    Objective: To determine whether correlates of white matter integrity can provide general as well as specific insight into the chronic effects of head injury coupled with depression symptom expression in professional football players. Method: We studied 26 retired National Football League (NFL) athletes who underwent diffusion tensor imaging (DTI) scanning. Depressive symptom severity was measured using the Beck Depression Inventory II (BDI-II) including affective, cognitive, and somatic subfactor scores (Buckley 3-factor model). Fractional anisotropy (FA) maps were processed using tract-based spatial statistics from FSL. Correlations between FA and BDI-II scores were assessed using both voxel-wise and region of interest (ROI) techniques, with ROIs that corresponded to white matter tracts. Tracts demonstrating significant correlations were further evaluated using a receiver operating characteristic curve that utilized the mean FA to distinguish depressed from nondepressed subjects. Results: Voxel-wise analysis identified widely distributed voxels that negatively correlated with total BDI-II and cognitive and somatic subfactors, with voxels correlating with the affective component (p < 0.05 corrected) localized to frontal regions. Four tract ROIs negatively correlated (p < 0.01) with total BDI-II: forceps minor, right frontal aslant tract, right uncinate fasciculus, and left superior longitudinal fasciculus. FA of the forceps minor differentiated depressed from nondepressed athletes with 100% sensitivity and 95% specificity. Conclusion: Depressive symptoms in retired NFL athletes correlate negatively with FA using either an unbiased voxel-wise or an ROI-based, tract-wise approach. DTI is a promising biomarker for depression in this population. PMID:23709590

  3. A prospective diffusion tensor imaging study in mild traumatic brain injury

    PubMed Central

    Mayer, A. R.; Ling, J.; Mannell, M. V.; Gasparovic, C.; Phillips, J. P.; Doezema, D.; Reichard, R.; Yeo, R. A.

    2010-01-01

    Objectives: Only a handful of studies have investigated the nature, functional significance, and course of white matter abnormalities associated with mild traumatic brain injury (mTBI) during the semi-acute stage of injury. The present study used diffusion tensor imaging (DTI) to investigate white matter integrity and compared the accuracy of traditional anatomic scans, neuropsychological testing, and DTI for objectively classifying mTBI patients from controls. Methods: Twenty-two patients with semi-acute mTBI (mean = 12 days postinjury), 21 matched healthy controls, and a larger sample (n = 32) of healthy controls were studied with an extensive imaging and clinical battery. A subset of participants was examined longitudinally 3–5 months after their initial visit. Results: mTBI patients did not differ from controls on clinical imaging scans or neuropsychological performance, although effect sizes were consistent with literature values. In contrast, mTBI patients demonstrated significantly greater fractional anisotropy as a result of reduced radial diffusivity in the corpus callosum and several left hemisphere tracts. DTI measures were more accurate than traditional clinical measures in classifying patients from controls. Longitudinal data provided preliminary evidence of partial normalization of DTI values in several white matter tracts. Conclusions: Current findings of white matter abnormalities suggest that cytotoxic edema may be present during the semi-acute phase of mild traumatic brain injury (mTBI). Initial mechanical damage to axons disrupts ionic homeostasis and the ratio of intracellular and extracellular water, primarily affecting diffusion perpendicular to axons. Diffusion tensor imaging measurement may have utility for objectively classifying mTBI, and may serve as a potential biomarker of recovery. GLOSSARY ADC = apparent diffusion coefficient; CC = corpus callosum; CCI = cortical impact injury model; CR = corona radiata; DTI = diffusion tensor imaging; EC = external capsule; FA = fractional anisotropy; FPI = fluid percussion injury model; HC = healthy controls; IC = internal capsule; JHU = Johns Hopkins University; MANCOVA = multivariate analysis of covariance; mTBI = mild traumatic brain injury; RD = radial diffusivity; ROI = region of interest; SCR = superior corona radiata; SLF = superior longitudinal fasciculus; UF = uncinate fasciculus. PMID:20089939

  4. White matter lesional predictors of chronic visual neglect: a longitudinal study.

    PubMed

    Lunven, Marine; Thiebaut De Schotten, Michel; Bourlon, Clémence; Duret, Christophe; Migliaccio, Raffaella; Rode, Gilles; Bartolomeo, Paolo

    2015-03-01

    Chronic visual neglect prevents brain-damaged patients from returning to an independent and active life. Detecting predictors of persistent neglect as early as possible after the stroke is therefore crucial to plan the relevant interventions. Neglect signs do not only depend on focal brain lesions, but also on dysfunction of large-scale brain networks connected by white matter bundles. We explored the relationship between markers of axonal degeneration occurring after the stroke and visual neglect chronicity. A group of 45 patients with unilateral strokes in the right hemisphere underwent cognitive testing for neglect twice, first at the subacute phase (<3 months after onset) and then at the chronic phase (>1 year). For each patient, magnetic resonance imaging including diffusion sequences was performed at least 4 months after the stroke. After masking each patient's lesion, we used tract-based spatial statistics to obtain a voxel-wise statistical analysis of the fractional anisotropy data. Twenty-seven patients had signs of visual neglect at initial testing. Only 10 of these patients had recovered from neglect at follow-up. When compared with patients without neglect, the group including all subacute neglect patients had decreased fractional anisotropy in the second (II) and third (III) branches of the right superior longitudinal fasciculus, as well as in the splenium of the corpus callosum. The subgroup of chronic patients showed reduced fractional anisotropy in a portion the splenium, the forceps major, which provides interhemispheric communication between regions of the occipital lobe and of the superior parietal lobules. The severity of neglect correlated with fractional anisotropy values in superior longitudinal fasciculus II/III for subacute patients and in its caudal portion for chronic patients. Our results confirm a key role of fronto-parietal disconnection in the emergence and chronic persistence of neglect, and demonstrate an implication of caudal interhemispheric disconnection in chronic neglect. Splenial disconnection may prevent fronto-parietal networks in the left hemisphere from resolving the activity imbalance with their right hemisphere counterparts, thus leading to persistent neglect. PMID:25609686

  5. Alzheimer's disease susceptibility genes APOE and TOMM40, and brain white matter integrity in the Lothian Birth Cohort 1936☆

    PubMed Central

    Lyall, Donald M.; Harris, Sarah E.; Bastin, Mark E.; Muñoz Maniega, Susana; Murray, Catherine; Lutz, Michael W.; Saunders, Ann M.; Roses, Allen D.; Valdés Hernández, Maria del C.; Royle, Natalie A.; Starr, John M.; Porteous, David. J.; Wardlaw, Joanna M.; Deary, Ian J.

    2014-01-01

    Apolipoprotein E (APOE) ε genotype has previously been significantly associated with cognitive, brain imaging, and Alzheimer's disease-related phenotypes (e.g., age of onset). In the TOMM40 gene, the rs10524523 (“523”) variable length poly-T repeat polymorphism has more recently been associated with similar ph/enotypes, although the allelic directions of these associations have varied between initial reports. Using diffusion magnetic resonance imaging tractography, the present study aimed to investigate whether there are independent effects of apolipoprotein E (APOE) and TOMM40 genotypes on human brain white matter integrity in a community-dwelling sample of older adults, the Lothian Birth Cohort 1936 (mean age = 72.70 years, standard deviation = 0.74, N approximately = 640–650; for most analyses). Some nominally significant effects were observed (i.e., covariate-adjusted differences between genotype groups at p < 0.05). For APOE, deleterious effects of ε4 “risk” allele presence (vs. absence) were found in the right ventral cingulum and left inferior longitudinal fasciculus. To test for biologically independent effects of the TOMM40 523 repeat, participants were stratified into APOE genotype subgroups, so that any significant effects could not be attributed to APOE variation. In participants with the APOE ε3/ε4 genotype, effects of TOMM40 523 status were found in the left uncinate fasciculus, left rostral cingulum, left ventral cingulum, and a general factor of white matter integrity. In all 4 of these tractography measures, carriers of the TOMM40 523 “short” allele showed lower white matter integrity when compared with carriers of the “long” and “very-long” alleles. Most of these effects survived correction for childhood intelligence test scores and vascular disease history, though only the effect of TOMM40 523 on the left ventral cingulum integrity survived correction for false discovery rate. The effects of APOE in this older population are more specific and restricted compared with those reported in previous studies, and the effects of TOMM40 on white matter integrity appear to be novel, although replication is required in large independent samples. PMID:24508314

  6. Alzheimer's disease susceptibility genes APOE and TOMM40, and brain white matter integrity in the Lothian Birth Cohort 1936.

    PubMed

    Lyall, Donald M; Harris, Sarah E; Bastin, Mark E; Muñoz Maniega, Susana; Murray, Catherine; Lutz, Michael W; Saunders, Ann M; Roses, Allen D; Valdés Hernández, Maria del C; Royle, Natalie A; Starr, John M; Porteous, David J; Wardlaw, Joanna M; Deary, Ian J

    2014-06-01

    Apolipoprotein E (APOE) ε genotype has previously been significantly associated with cognitive, brain imaging, and Alzheimer's disease-related phenotypes (e.g., age of onset). In the TOMM40 gene, the rs10524523 ("523") variable length poly-T repeat polymorphism has more recently been associated with similar ph/enotypes, although the allelic directions of these associations have varied between initial reports. Using diffusion magnetic resonance imaging tractography, the present study aimed to investigate whether there are independent effects of apolipoprotein E (APOE) and TOMM40 genotypes on human brain white matter integrity in a community-dwelling sample of older adults, the Lothian Birth Cohort 1936 (mean age = 72.70 years, standard deviation = 0.74, N approximately = 640-650; for most analyses). Some nominally significant effects were observed (i.e., covariate-adjusted differences between genotype groups at p < 0.05). For APOE, deleterious effects of ε4 "risk" allele presence (vs. absence) were found in the right ventral cingulum and left inferior longitudinal fasciculus. To test for biologically independent effects of the TOMM40 523 repeat, participants were stratified into APOE genotype subgroups, so that any significant effects could not be attributed to APOE variation. In participants with the APOE ε3/ε4 genotype, effects of TOMM40 523 status were found in the left uncinate fasciculus, left rostral cingulum, left ventral cingulum, and a general factor of white matter integrity. In all 4 of these tractography measures, carriers of the TOMM40 523 "short" allele showed lower white matter integrity when compared with carriers of the "long" and "very-long" alleles. Most of these effects survived correction for childhood intelligence test scores and vascular disease history, though only the effect of TOMM40 523 on the left ventral cingulum integrity survived correction for false discovery rate. The effects of APOE in this older population are more specific and restricted compared with those reported in previous studies, and the effects of TOMM40 on white matter integrity appear to be novel, although replication is required in large independent samples. PMID:24508314

  7. Frontoparietal Structural Connectivity Mediates the Top-Down Control of Neuronal Synchronization Associated with Selective Attention

    PubMed Central

    Marshall, Tom Rhys; Bergmann, Til Ole; Jensen, Ole

    2015-01-01

    Neuronal synchronization reflected by oscillatory brain activity has been strongly implicated in the mechanisms supporting selective gating. We here aimed at identifying the anatomical pathways in humans supporting the top-down control of neuronal synchronization. We first collected diffusion imaging data using magnetic resonance imaging to identify the medial branch of the superior longitudinal fasciculus (SLF), a white-matter tract connecting frontal control areas to parietal regions. We then quantified the modulations in oscillatory activity using magnetoencephalography in the same subjects performing a spatial attention task. We found that subjects with a stronger SLF volume in the right compared to the left hemisphere (or vice versa) also were the subjects who had a better ability to modulate right compared to left hemisphere alpha and gamma band synchronization, with the latter also predicting biases in reaction time. Our findings implicate the medial branch of the SLF in mediating top-down control of neuronal synchronization in sensory regions that support selective attention. PMID:26441286

  8. Structural integrity of the limbic-prefrontal connection: Neuropathological correlates of anxiety in Williams syndrome.

    PubMed

    Ng, Rowena; Brown, Timothy T; Järvinen, Anna M; Erhart, Matthew; Korenberg, Julie R; Bellugi, Ursula; Halgren, Eric

    2016-04-01

    Williams syndrome (WS) is a genetic condition characterized by a hypersocial personality and desire to form close relationships, juxtaposed with significant anxieties of nonsocial events. The neural underpinnings of anxiety in individuals with WS are currently unknown. Aberrations in the anatomical and microstructural integrity of the uncinate fasciculus (UF) have been recently implicated in social and generalized anxiety disorders. Based on these findings, we tested the hypothesis that the reported anxieties in individuals with WS share similar neuropathological correlates. Toward this end, diffusion tensor imaging (DTI) methods were employed to examine the microstructural integrity (fractional anisotropy, mean diffusivity, longitudinal diffusivity) of the UF in 18 WS and 15 typically developing adults (TD). Anxiety and sociability questionnaires were administered to determine associations with DTI indices of UF across groups. Results revealed comparable white matter integrity of the UF across groups, yet elevated subjective experience of anxiety in those with WS. Additionally, sociability and UF microstructural properties were dissociated across both groups. Whereas no relationships were found between DTI indices and anxiety in TD participants, strong negative associations were observed between these constructs in individuals with WS. Findings indicated that increased anxiety manifested by individuals with WS was associated with DTI measures of the UF and may signal structural or possibly physiological aberration involving this tract within the prefrontal-temporal network. PMID:26214361

  9. Correlates of virtual navigation performance in older adults.

    PubMed

    Korthauer, Laura E; Nowak, Nicole T; Moffat, Scott D; An, Yang; Rowland, Laura M; Barker, Peter B; Resnick, Susan M; Driscoll, Ira

    2016-03-01

    Despite considerable evidence for deleterious effects of aging on place learning and memory, less is known about the trajectory and the putative neural mechanisms of these decrements. The virtual Morris water task (vMWT) is a human analog of a nonhuman spatial navigation task. The present study investigated longitudinal changes in place learning in 51 healthy, nondemented adults (age 30-83 years) who completed the vMWT and a neuropsychological battery at 2 time-points (interval = ∼8 years). We also assessed cross-sectional associations between vMWT and brain structure, biochemical integrity, and standardized neuropsychological measures in a subset of 22 individuals who underwent magnetic resonance imaging at follow-up. Despite no longitudinal decrement in vMWT performance, there were cross-sectional age differences on the vMWT favoring younger adults. Negative associations were observed between vMWT latency and gray matter volumes in the right hippocampus, bilateral thalamus, and right medial orbitofrontal cortex and between vMWT latency and white matter fractional anisotropy in the bilateral uncinate fasciculus. Collectively, these results suggest a pattern of differences in the structural integrity of regions supporting successful navigation even in the absence of longitudinal performance decrements. PMID:26923408

  10. Bilateral Fronto-Parietal Integrity in Young Chronic Cigarette Smokers: A Diffusion Tensor Imaging Study

    PubMed Central

    Liao, Yanhui; Tang, Jinsong; Deng, Qijian; Deng, Yongwen; Luo, Tao; Wang, Xuyi; Chen, Hongxian; Liu, Tieqiao; Chen, Xiaogang; Brody, Arthur L.; Hao, Wei

    2011-01-01

    Background Cigarette smoking continues to be the leading cause of preventable morbidity and mortality in China and other countries. Previous studies have demonstrated gray matter loss in chronic smokers. However, only a few studies assessed the changes of white matter integrity in this group. Based on those previous reports of alterations in white matter integrity in smokers, the aim of this study was to examine the alteration of white matter integrity in a large, well-matched sample of chronic smokers and non-smokers. Methodology/Principal Findings Using in vivo diffusion tensor imaging (DTI) to measure the differences of whole-brain white matter integrity between 44 chronic smoking subjects (mean age, 28.0±5.6 years) and 44 healthy age- and sex-matched comparison non-smoking volunteers (mean age, 26.3±5.8 years). DTI was performed on a 3-Tesla Siemens scanner (Allegra; Siemens Medical System). The data revealed that smokers had higher fractional anisotropy (FA) than healthy non-smokers in almost symmetrically bilateral fronto-parietal tracts consisting of a major white matter pathway, the superior longitudinal fasciculus (SLF). Conclusion/Significance We found the almost symmetrically bilateral fronto-parietal whiter matter changes in a relatively large sample of chronic smokers. These findings support the hypothesis that chronic cigarette smoking involves alterations of bilateral fronto-parietal connectivity. PMID:22069452

  11. Possible confounding factors on cerebral diffusion tensor imaging measurements

    PubMed Central

    Nenonen, Miina; Hakulinen, Ullamari; Brander, Antti; Ohman, Juha; Dastidar, Prasun

    2015-01-01

    Background Diffusion tensor imaging (DTI) is prone to numerous systemic confounding factors that should be acknowledged to avoid false conclusions. Purpose To investigate the possible effects of age, gender, smoking, alcohol consumption, and education on cerebral DTI parameters in a generally healthy homogenous sample with no neurological or psychiatric diseases. Material and Methods Forty (n?=?40) subjects (mean age, 40.3 years; SD, 12.3) underwent brain DTI with 3 T magnetic resonance imaging (MRI). At enrolment, all the subjects were interviewed with respect to general health, education, history of smoking, and alcohol consumption. Studied DTI parameters included: (i) fractional anisotropy (FA); and (ii) apparent diffusion coefficient (ADC). Region-of-interest (ROI)-based measurements were estimated at 13 anatomical locations bilaterally on the axial images, except for the corpus callosum in which the ROIs were placed on the sagittal images. Circular ROI measurements were mainly used. Freehand ROI method was used with the forceps minor, uncinate fasciculus, and thalamus. Intra-observer variability and repeatability were assessed. Results The most consistent finding was that aging decreased FA values in the frontal brain regions. Regarding the other confounding factors, the results were discontinuous and no concrete conclusions could be drawn from these findings. In general, intra-observer repeatability of the DTI measurement was considered relatively good. Conclusion Age should be noted as considerable confounding factors in ROI-based DTI analysis. More research on the effects of gender, smoking, alcohol consumption, and education is needed. PMID:25793107

  12. Inter-individual differences in audio-motor learning of piano melodies and white matter fiber tract architecture.

    PubMed

    Engel, Annerose; Hijmans, Brenda S; Cerliani, Leonardo; Bangert, Marc; Nanetti, Luca; Keller, Peter E; Keysers, Christian

    2014-05-01

    Humans vary substantially in their ability to learn new motor skills. Here, we examined inter-individual differences in learning to play the piano, with the goal of identifying relations to structural properties of white matter fiber tracts relevant to audio-motor learning. Non-musicians (n = 18) learned to perform three short melodies on a piano keyboard in a pure audio-motor training condition (vision of their own fingers was occluded). Initial learning times ranged from 17 to 120 min (mean ± SD: 62 ± 29 min). Diffusion-weighted magnetic resonance imaging was used to derive the fractional anisotropy (FA), an index of white matter microstructural arrangement. A correlation analysis revealed that higher FA values were associated with faster learning of piano melodies. These effects were observed in the bilateral corticospinal tracts, bundles of axons relevant for the execution of voluntary movements, and the right superior longitudinal fasciculus, a tract important for audio-motor transformations. These results suggest that the speed with which novel complex audio-motor skills can be acquired may be determined by variability in structural properties of white matter fiber tracts connecting brain areas functionally relevant for audio-motor learning. PMID:23904213

  13. Spinal cord neuron inputs to the cuneate nucleus that partially survive dorsal column lesions: A pathway that could contribute to recovery after spinal cord injury.

    PubMed

    Liao, Chia-Chi; DiCarlo, Gabriella E; Gharbawie, Omar A; Qi, Hui-Xin; Kaas, Jon H

    2015-10-01

    Dorsal column lesions at a high cervical level deprive the cuneate nucleus and much of the somatosensory system of its major cutaneous inputs. Over weeks of recovery, much of the hand representations in the contralateral cortex are reactivated. One possibility for such cortical reactivation by hand afferents is that preserved second-order spinal cord neurons reach the cuneate nucleus through pathways that circumvent the dorsal column lesions, contributing to cortical reactivation in an increasingly effective manner over time. To evaluate this possibility, we first injected anatomical tracers into the cuneate nucleus and plotted the distributions of labeled spinal cord neurons and fibers in control monkeys. Large numbers of neurons in the dorsal horn of the cervical spinal cord were labeled, especially ipsilaterally in lamina IV. Labeled fibers were distributed in the cuneate fasciculus and lateral funiculus. In three other squirrel monkeys, unilateral dorsal column lesions were placed at the cervical segment 4 level and tracers were injected into the ipsilateral cuneate nucleus. Two weeks later, a largely unresponsive hand representation in contralateral somatosensory cortex confirmed the effectiveness of the dorsal column lesion. However, tracer injections in the cuneate nucleus labeled only about 5% of the normal number of dorsal horn neurons, mainly in lamina IV, below the level of lesions. Our results revealed a small second-order pathway to the cuneate nucleus that survives high cervical dorsal column lesions by traveling in the lateral funiculus. This could be important for cortical reactivation by hand afferents, and recovery of hand use. PMID:25845707

  14. Predictors of Neurocognitive Syndromes in Combat Veterans

    PubMed Central

    Roy, Michael J; Gill, Jessica; Leaman, Suzanne; Law, Wendy; Ndiongue, Rochelle; Taylor, Patricia; Kim, Hyung-Suk; Bieler, Gayle S; Garge, Nikhil; Rapp, Paul E; Keyser, David; Nathan, Dominic; Xydakis, Michael; Pham, Dzung; Wassermann, Eric

    2015-01-01

    Traumatic brain injury, depression and posttraumatic stress disorder (PTSD) are neurocognitive syndromes often associated with impairment of physical and mental health, as well as functional status. These syndromes are also frequent in military service members (SMs) after combat, although their presentation is often delayed until months after their return. The objective of this prospective cohort study was the identification of independent predictors of neurocognitive syndromes upon return from deployment could facilitate early intervention to prevent disability. We completed a comprehensive baseline assessment, followed by serial evaluations at three, six, and 12 months, to assess for new-onset PTSD, depression, or postconcussive syndrome (PCS) in order to identify baseline factors most strongly associated with subsequent neurocognitive syndromes. On serial follow-up, seven participants developed at least one neurocognitive syndrome: five with PTSD, one with depression and PTSD, and one with PCS. On univariate analysis, 60 items were associated with syndrome development at p < 0.15. Decision trees and ensemble tree multivariate models yielded four common independent predictors of PTSD: right superior longitudinal fasciculus tract volume on MRI; resting state connectivity between the right amygdala and left superior temporal gyrus (BA41/42) on functional MRI; and single nucleotide polymorphisms in the genes coding for myelin basic protein as well as brain-derived neurotrophic factor. Our findings require follow-up studies with greater sample size and suggest that neuroimaging and molecular biomarkers may help distinguish those at high risk for post-deployment neurocognitive syndromes. PMID:26251769

  15. Musicians and music making as a model for the study of brain plasticity.

    PubMed

    Schlaug, Gottfried

    2015-01-01

    Playing a musical instrument is an intense, multisensory, and motor experience that usually commences at an early age and requires the acquisition and maintenance of a range of sensory and motor skills over the course of a musician's lifetime. Thus, musicians offer an excellent human model for studying behavioral-cognitive as well as brain effects of acquiring, practicing, and maintaining these specialized skills. Research has shown that repeatedly practicing the association of motor actions with specific sound and visual patterns (musical notation), while receiving continuous multisensory feedback will strengthen connections between auditory and motor regions (e.g., arcuate fasciculus) as well as multimodal integration regions. Plasticity in this network may explain some of the sensorimotor and cognitive enhancements that have been associated with music training. Furthermore, the plasticity of this system as a result of long term and intense interventions suggest the potential for music making activities (e.g., forms of singing) as an intervention for neurological and developmental disorders to learn and relearn associations between auditory and motor functions such as vocal motor functions. PMID:25725909

  16. White Matter Abnormalities in Schizophrenia and Schizotypal Personality Disorder

    PubMed Central

    Lener, Marc S.; Wong, Edmund; Tang, Cheuk Y.; Byne, William; Goldstein, Kim E.; Blair, Nicholas J.; Haznedar, M. Mehmet; New, Antonia S.; Chemerinski, Eran; Chu, King-Wai; Rimsky, Liza S.; Siever, Larry J.; Koenigsberg, Harold W.; Hazlett, Erin A.

    2015-01-01

    Prior diffusion tensor imaging (DTI) studies examining schizotypal personality disorder (SPD) and schizophrenia, separately have shown that compared with healthy controls (HCs), patients show frontotemporal white matter (WM) abnormalities. This is the first DTI study to directly compare WM tract coherence with tractography and fractional anisotropy (FA) across the schizophrenia spectrum in a large sample of demographically matched HCs (n = 55), medication-naive SPD patients (n = 49), and unmedicated/never-medicated schizophrenia patients (n = 22) to determine whether (a) frontal-striatal-temporal WM tract abnormalities in schizophrenia are similar to, or distinct from those observed in SPD; and (b) WM tract abnormalities are associated with clinical symptom severity indicating a common underlying pathology across the spectrum. Compared with both the HC and SPD groups, schizophrenia patients showed WM abnormalities, as indexed by lower FA in the temporal lobe (inferior longitudinal fasciculus) and cingulum regions. SPD patients showed lower FA in the corpus callosum genu compared with the HC group, but this regional abnormality was more widespread in schizophrenia patients. Across the schizophrenia spectrum, greater WM disruptions were associated with greater symptom severity. Overall, frontal-striatal-temporal WM dysconnectivity is attenuated in SPD compared with schizophrenia patients and may mitigate the emergence of psychosis. PMID:24962608

  17. The Plasticity of Brain Gray Matter and White Matter following Lower Limb Amputation

    PubMed Central

    Jiang, Guangyao; Yin, Xuntao; Li, Chuanming; Li, Lei; Zhao, Lu; Evans, Alan C.; Jiang, Tianzi; Wu, Jixiang; Wang, Jian

    2015-01-01

    Accumulating evidence has indicated that amputation induces functional reorganization in the sensory and motor cortices. However, the extent of structural changes after lower limb amputation in patients without phantom pain remains uncertain. We studied 17 adult patients with right lower limb amputation and 18 healthy control subjects using T1-weighted magnetic resonance imaging and diffusion tensor imaging. Cortical thickness and fractional anisotropy (FA) of white matter (WM) were investigated. In amputees, a thinning trend was seen in the left premotor cortex (PMC). Smaller clusters were also noted in the visual-to-motor regions. In addition, the amputees also exhibited a decreased FA in the right superior corona radiata and WM regions underlying the right temporal lobe and left PMC. Fiber tractography from these WM regions showed microstructural changes in the commissural fibers connecting the bilateral premotor cortices, compatible with the hypothesis that amputation can lead to a change in interhemispheric interactions. Finally, the lower limb amputees also displayed significant FA reduction in the right inferior frontooccipital fasciculus, which is negatively correlated with the time since amputation. In conclusion, our findings indicate that the amputation of lower limb could induce changes in the cortical representation of the missing limb and the underlying WM connections. PMID:26587289

  18. Neuromarkers of the common angiotensinogen polymorphism in healthy older adults: A comprehensive assessment of white matter integrity and cognition.

    PubMed

    Salminen, Lauren E; Schofield, Peter R; Pierce, Kerrie D; Zhao, Yi; Luo, Xi; Wang, Youdan; Laidlaw, David H; Cabeen, Ryan P; Conturo, Thomas E; Tate, David F; Akbudak, Erbil; Lane, Elizabeth M; Heaps, Jodi M; Bolzenius, Jacob D; Baker, Laurie M; Cagle, Lee M; Paul, Robert H

    2016-01-01

    The common angiotensinogen (AGT) M268T polymorphism (rs699; historically referred to as M235T) has been identified as a significant risk factor for cerebrovascular pathologies, yet it is unclear if healthy older adults carrying the threonine amino acid variant have a greater risk for white matter damage in specific fiber tracts. Further, the impact of the threonine variant on cognitive function remains unknown. The present study utilized multiple indices of diffusion tensor imaging (DTI) and neuropsychological assessment to examine the integrity of specific white matter tracts and cognition between individuals with homozygous genotypes of M268T (MetMet n=27, ThrThr n=27). Differences in subcortical hyperintensity (SH) volume were also examined between groups. Results indicated that the threonine variant was associated with significantly reduced integrity in the superior longitudinal fasciculus (SLF) and the cingulate gyrus segment of the cingulum bundle (cingulum CG) compared to those with the methionine variant, and poorer cognitive performance on tests of attention/processing speed and language. Despite these associations, integrity of these tracts did not significantly mediate relationships between cognition and genetic status, and SH did not differ significantly between groups. Collectively our results suggest that the threonine variant of M268T is a significant risk factor for abnormalities in specific white matter tracts and cognitive domains in healthy older adults, independent of SH burden. PMID:26318936

  19. F-spondin/spon1b expression patterns in developing and adult zebrafish.

    PubMed

    Akle, Veronica; Guelin, Emmanuel; Yu, Lili; Brassard-Giordano, Helena; Slack, Barbara E; Zhdanova, Irina V

    2012-01-01

    F-spondin, an extracellular matrix protein, is an important player in embryonic morphogenesis and CNS development, but its presence and role later in life remains largely unknown. We generated a transgenic zebrafish in which GFP is expressed under the control of the F-spondin (spon1b) promoter, and used it in combination with complementary techniques to undertake a detailed characterization of the expression patterns of F-spondin in developing and adult brain and periphery. We found that F-spondin is often associated with structures forming long neuronal tracts, including retinal ganglion cells, the olfactory bulb, the habenula, and the nucleus of the medial longitudinal fasciculus (nMLF). F-spondin expression coincides with zones of adult neurogenesis and is abundant in CSF-contacting secretory neurons, especially those in the hypothalamus. Use of this new transgenic model also revealed F-spondin expression patterns in the peripheral CNS, notably in enteric neurons, and in peripheral tissues involved in active patterning or proliferation in adults, including the endoskeleton of zebrafish fins and the continuously regenerating pharyngeal teeth. Moreover, patterning of the regenerating caudal fin following fin amputation in adult zebrafish was associated with F-spondin expression in the blastema, a proliferative region critical for tissue reconstitution. Together, these findings suggest major roles for F-spondin in the CNS and periphery of the developing and adult vertebrate. PMID:22768035

  20. Limited microstructural and connectivity deficits despite subcortical volume reductions in school-aged children born preterm with very low birth weight.

    PubMed

    Sølsnes, Anne Elisabeth; Sripada, Kam; Yendiki, Anastasia; Bjuland, Knut Jørgen; Østgård, Heidi Furre; Aanes, Synne; Grunewaldt, Kristine Hermansen; Løhaugen, Gro C; Eikenes, Live; Håberg, Asta K; Rimol, Lars M; Skranes, Jon

    2016-04-15

    Preterm birth and very low birth weight (VLBW, ≤1500g) are worldwide problems that burden survivors with lifelong cognitive, psychological, and physical challenges. In this multimodal structural magnetic resonance imaging (MRI) and diffusion MRI (dMRI) study, we investigated differences in subcortical brain volumes and white matter tract properties in children born preterm with VLBW compared to term-born controls (mean age=8years). Subcortical brain structure volumes and cortical thickness estimates were obtained, and fractional anisotropy (FA), mean diffusivity (MD), radial diffusivity (RD), and axial diffusivity (AD) were generated for 18 white matter tracts. We also assessed structural relationships between white matter tracts and cortical thickness of the tract endpoints. Compared to controls, the VLBW group had reduced volumes of thalamus, globus pallidus, corpus callosum, cerebral white matter, ventral diencephalon, and brain stem, while the ventricular system was larger in VLBW subjects, after controlling for age, sex, IQ, and estimated total intracranial volume. For the dMRI parameters, group differences were not significant at the whole-tract level, though pointwise analysis found shorter segments affected in forceps minor and left superior longitudinal fasciculus - temporal bundle. IQ did not correlate with subcortical volumes or dMRI measures in the VLBW group. While the deviations in subcortical volumes were substantial, there were few differences in dMRI measures between the two groups, which may reflect the influence of advances in perinatal care on white matter development. PMID:26712340

  1. Is meditation associated with altered brain structure? A systematic review and meta-analysis of morphometric neuroimaging in meditation practitioners.

    PubMed

    Fox, Kieran C R; Nijeboer, Savannah; Dixon, Matthew L; Floman, James L; Ellamil, Melissa; Rumak, Samuel P; Sedlmeier, Peter; Christoff, Kalina

    2014-06-01

    Numerous studies have begun to address how the brain's gray and white matter may be shaped by meditation. This research is yet to be integrated, however, and two fundamental questions remain: Is meditation associated with altered brain structure? If so, what is the magnitude of these differences? To address these questions, we reviewed and meta-analyzed 123 brain morphology differences from 21 neuroimaging studies examining ?300 meditation practitioners. Anatomical likelihood estimation (ALE) meta-analysis found eight brain regions consistently altered in meditators, including areas key to meta-awareness (frontopolar cortex/BA 10), exteroceptive and interoceptive body awareness (sensory cortices and insula), memory consolidation and reconsolidation (hippocampus), self and emotion regulation (anterior and mid cingulate; orbitofrontal cortex), and intra- and interhemispheric communication (superior longitudinal fasciculus; corpus callosum). Effect size meta-analysis (calculating 132 effect sizes from 16 studies) suggests a global 'medium' effect size (Cohen's d¯=0.46; r¯=.19). Publication bias and methodological limitations are strong concerns, however. Further research using rigorous methods is required to definitively link meditation practice to altered brain morphology. PMID:24705269

  2. The relationship of brain structure to age and executive functioning in adolescent disruptive behavior disorder.

    PubMed

    Hummer, Tom A; Wang, Yang; Kronenberger, William G; Dunn, David W; Mathews, Vincent P

    2015-03-30

    Characterizing brain maturation in adolescents with disruptive behavior disorders (DBDs) may provide insight into the progression of their behavioral deficits. Therefore, this study examined how age and executive functioning were related to structural neural characteristics in DBD. Thirty-three individuals (aged 13-17) with a DBD, along with a matched control sample, completed neuropsychological testing and underwent magnetic resonance imaging (MRI) to measure gray matter volume and microstructural white matter properties. Voxel-based morphometry quantified gray matter volume, and diffusion tensor imaging measured fractional anisotropy (FA) in white matter tracts. In the anterior cingulate, gray matter volume decreased with age in healthy controls but showed no such change in the DBD sample. In the corpus callosum and superior longitudinal fasciculus (SLF), FA increased with age in the control sample significantly more than in the DBD sample. Executive functioning, particularly working memory, was associated with SLF FA bilaterally. However, the relationship of SLF FA to working memory performance was weaker in the DBD sample. These data suggest that youth with DBD have altered brain development compared with typically developing youth. The abnormal maturation of the anterior cingulate and frontoparietal tracts during adolescence may contribute to the persistence of behavioral deficits in teens with a DBD. PMID:25533028

  3. The habenula governs the attribution of incentive salience to reward predictive cues

    PubMed Central

    Danna, Carey L.; Shepard, Paul D.; Elmer, Greg I.

    2013-01-01

    The attribution of incentive salience to reward associated cues is critical for motivation and the pursuit of rewards. Disruptions in the integrity of the neural systems controlling these processes can lead to avolition and anhedonia, symptoms that cross the diagnostic boundaries of many neuropsychiatric illnesses. Here, we consider whether the habenula (Hb), a region recently demonstrated to encode negatively valenced events, also modulates the attribution of incentive salience to a neutral cue predicting a food reward. The Pavlovian autoshaping paradigm was used in the rat as an investigative tool to dissociate Pavlovian learning processes imparting strictly predictive value from learning that attributes incentive motivational value. Electrolytic lesions of the fasciculus retroflexus (fr), the sole pathway through which descending Hb efferents are conveyed, significantly increased incentive salience as measured by conditioned approaches to a cue light predictive of reward. Conversely, generation of a fictive Hb signal via fr stimulation during CS+ presentation significantly decreased the incentive salience of the predictive cue. Neither manipulation altered the reward predictive value of the cue as measured by conditioned approach to the food. Our results provide new evidence supporting a significant role for the Hb in governing the attribution of incentive motivational salience to reward predictive cues and further imply that pathological changes in Hb activity could contribute to the aberrant pursuit of debilitating goals or avolition and depression-like symptoms. PMID:24368898

  4. White matter diffusion abnormalities in patients with psychogenic non-epileptic seizures.

    PubMed

    Lee, Seongtaek; Allendorfer, Jane B; Gaston, Tyler E; Griffis, Joseph C; Hernando, Kathleen A; Knowlton, Robert C; Szaflarski, Jerzy P; Ver Hoef, Lawrence W

    2015-09-16

    The purpose of this study was to conduct a preliminary investigation of the white matter characteristics in patients with psychogenic non-epileptic seizures (PNES). Diffusion Tensor Imaging (DTI) data were collected at 3T in 16 patients with PNES and 16 age- and sex-matched healthy controls (HC). All patients with PNES had their diagnosis confirmed via video/EEG monitoring; HCs had no comorbid neurological or psychiatric conditions. DTI indices including fractional anisotropy (FA), and mean diffusivity (MD) were calculated and compared between patients with PNES and HCs using Tract-Based Spatial Statistics (TBSS). Significantly higher FA values were observed in patients with PNES in the left corona radiata, left internal and external capsules, left superior temporal gyrus, as well as left uncinate fasciculus (UF) (P<0.05; corrected for multiple comparisons). There was no significant change in other indices between patients with PNES and HCs. These findings suggest that patients with PNES have significantly altered white matter structural connectivity when compared to age- and sex-matched HCs. These abnormalities are present in left hemispheric regions associated with emotion regulation and motor pathways. While the relationship between the pathophysiology of PNES and these abnormalities is not entirely clear, this work provides an initial basis to guide future prospective studies. PMID:25979311

  5. Genetic & Neuronanatomic Associations in Sporadic Frontotemporal Lobar Degeneration

    PubMed Central

    McMillan, Corey T.; Toledo, Jon B.; Avants, Brian B.; Cook, Philip A.; Wood, Elisabeth M.; Suh, Eunran; Irwin, David J.; Powers, John; Olm, Christopher; Elman, Lauren; McCluskey, Leo; Schellenberg, Gerard D.; Lee, Virginia M.-Y.; Trojanowski, John Q.; Van Deerlin, Vivianna M.; Grossman, Murray

    2014-01-01

    Genome-wide association studies have identified SNPs that are sensitive for tau or TDP-43 pathology in frontotemporal lobar degeneration (FTLD). Neuroimaging analyses have revealed distinct distributions of disease in FTLD patients with genetic mutations. However, genetic influences on neuroanatomical structure in sporadic FTLD have not been assessed. In this report we use novel multivariate tools, eigenanatomy and sparse canonical correlation analysis (SCCAN), to identify associations between SNPs and neuroanatomical structure in sporadic FTLD. MRI analyses revealed that rs8070723 (MAPT) was associated with grey matter variance in the temporal cortex. DTI analyses revealed that rs1768208 (MOBP), rs646776 (near SORT1) and rs5848 (PGRN) were associated with white matter variance in the midbrain and superior longitudinal fasciculus. In an independent autopsy series we observed that rs8070723 and rs1768208 conferred significant risk of tau pathology relative to TDP-43, and rs646776 conferred increased risk of TDP-43 pathology relative to tau. Identified brain regions and SNPs may help provide an in vivo screen for underlying pathology in FTLD and contribute to our understanding of sporadic FTLD. PMID:24373676

  6. Methadone-induced Damage to White Matter Integrity in Methadone Maintenance Patients: A Longitudinal Self-control DTI Study.

    PubMed

    Li, Wei; Li, Qiang; Wang, Yarong; Zhu, Jia; Ye, Jianjun; Yan, Xuejiao; Li, Yongbin; Chen, Jiajie; Liu, Jierong; Li, Zhe; Wang, Wei; Liu, Yijun

    2016-01-01

    Methadone maintenance treatment (MMT) can induce impairments in brain function and structure, despite its clinical effectiveness. However, the effect of chronic MMT on brain white matter (WM) is not fully known. Thirty-three MMT patients underwent diffusion tensor imaging (DTI) twice - at the start of the study (Scan1) and one year later (Scan2). Tract-based spatial statistics were used to investigate changes in fractional anisotropy (FA), axial diffusivity (AD) and radial diffusivity (RD) between the two scans. The correlations between DTI indices and methadone consumption and neuropsychological status were analysed. We found significantly decreased FA, decreased AD and increased RD in Scan2 in extensive WM regions; overlapping regions were found in the left posterior limb and the retrolenticular part of internal capsule, superior and posterior corona radiata, bilateral external capsule and the right superior longitudinal fasciculus. In addition, the change of FA in the overlapping regions was positively correlated with the accumulated dosage of methadone use, the RD value in Scan2 and non-planning impulsiveness (NPI) measured at follow-up. The results suggest that methadone has damaging effects on WM integrity. The dose-dependent pattern and characteristics of the impairment may suggest new strategies for MMT. PMID:26794650

  7. A possible mechanism for PTSD symptoms in patients with traumatic brain injury: central autonomic network disruption

    PubMed Central

    Williamson, John B.; Heilman, Kenneth M.; Porges, Eric C.; Lamb, Damon G.; Porges, Stephen W.

    2013-01-01

    Patients with traumatic brain injuries (TBI) often develop post traumatic stress disorder (PTSD). This syndrome, defined and diagnosed by psychological and behavioral features, is associated with symptoms such as anxiety and anger with an increase of arousal and vigilance, as well as flashbacks and nightmares. Many of these features and symptoms observed in PTSD may be in part the result of altered autonomic nervous system (ANS) activity in response to psychological and physical challenges. Brain imaging has documented that TBI often induces white matter damage to pathways associated with the anterior limb of the internal capsule and uncinate fasciculus. Since these white matter structures link neocortical networks with subcortical and limbic structures that regulate autonomic control centers, injury to these pathways may induce a loss of inhibitory control of the ANS. In this review, the autonomic features associated with PTSD are discussed in the context of traumatic brain injury. We posit that TBI induced damage to networks that regulate the ANS increase vulnerability to PTSD. The means by which the vulnerability can be measured and tested are also discussed. PMID:24391583

  8. BRAIN ACTIVITY DURING BLADDER FILLING IS RELATED TO WHITE MATTER STRUCTURAL CHANGES IN OLDER WOMEN WITH URINARY INCONTINENCE

    PubMed Central

    Tadic, Stasa D.; Griffiths, Derek; Murrin, Andrew; Schaefer, Werner; Aizenstein, Howard J.; Resnick, Neil M.

    2010-01-01

    Evidence from longitudinal studies in community-dwelling elderly links complaints of urgency and urinary incontinence with structural white matter changes known as white matter hyperintensities (WMH). How WMH might lead to incontinence remains unknown, since information about how they relate to neural circuits involved in continence control is lacking. The aim of this study was to investigate the role of WMH in altered brain activity in older women with urgency incontinence. In a cross-sectional study, we measured WMH, globally and in specific white matter tracts, and correlated them with regional brain activity measured by fMRI (combined with simultaneous urodynamic monitoring) during bladder filling and reported 'urgency'. We postulated that increase in global WMH burden would be associated with changes (either attenuation or reinforcement) in responses to bladder filling in brain regions involved in bladder control. Secondly, we proposed that such apparent effects of global WMH burden might be specifically related to the burden in a few critical white matter pathways. The results showed that regional activations (e.g. medial/superior frontal gyrus adjacent to dorsal ACG) and deactivations (e.g. perigenual ACG adjacent to ventromedial prefrontal cortex) became more prominent with increased global WMH burden, suggesting that activity aimed at suppressing urgency was augmented. Secondary analyses confirmed that the apparent effect of global WMH burden might reflect the presence of WMH in specific pathways (anterior thalamic radiation and superior longitudinal fasciculus), thus affecting connections between key regions and suggesting possible mechanisms involved in continence control. PMID:20302947

  9. Brain structure and cognitive correlates of body mass index in healthy older adults

    PubMed Central

    Bolzenius, Jacob D.; Laidlaw, David H.; Cabeen, Ryan P.; Conturo, Thomas E.; McMichael, Amanda R.; Lane, Elizabeth M.; Heaps, Jodi M.; Salminen, Lauren E.; Baker, Laurie M.; Scott, Staci E.; Cooley, Sarah A.; Gunstad, John; Paul, Robert H.

    2014-01-01

    Obesity, commonly measured with body mass index (BMI), is associated with numerous deleterious health conditions including alterations in brain integrity related to advanced age. Prior research has suggested that white matter integrity observed using diffusion tensor imaging (DTI) is altered in relation to high BMI, but the integrity of specific white matter tracts remains poorly understood. Additionally, no studies have examined white matter tract integrity in conjunction with neuropsychological evaluation associated with BMI among older adults. The present study examined white matter tract integrity using DTI and cognitive performance associated with BMI in 62 healthy older adults (20 males, 42 females) aged 51 to 81. Results revealed that elevated BMI was associated with lower fractional anisotropy (FA) in the uncinate fasciculus, though there was no evidence of an age by BMI interaction relating to FA in this tract. No relationships were observed between BMI and other white matter tracts or cognition after controlling for demographic variables. Findings suggest that elevated BMI is associated with lower structural integrity in a brain region connecting frontal and temporal lobes and this alteration precedes cognitive dysfunction. Future studies should examine biological mechanisms that mediate the relationships between BMI and white matter tract integrity, as well as the evolution of these abnormalities utilizing longitudinal designs. PMID:25448431

  10. White-matter connectivity related to paliperidone treatment response in patients with schizophrenia.

    PubMed

    Kim, Min-Kyoung; Kim, Borah; Lee, Kang Soo; Kim, Chan Mo; Bang, Seong Yun; Choi, Tai Kiu; Lee, Sang-Hyuk

    2016-03-01

    The objective of this study was to examine whether white-matter (WM) connectivity of patients with schizophrenia at early stage of treatment is related to treatment response after paliperidone extended-release (ER) treatment. Forty-one patients with schizophrenia and 17 age- and sex-matched healthy control subjects were included in this study. Brain magnetic resonance scans at 3 Tesla were conducted at early stage of treatment. Voxel-wise statistical analysis of the fractional anisotropy (FA) data was performed using Tract-Based Spatial Statistics. At baseline and eight weeks after paliperidone treatment, patients were assessed using the Positive and Negative Syndrome Scale, the Scale for the Assessment of Positive Symptoms and the Scale for the Assessment of Negative Symptoms. Among the patients with schizophrenia, the FA values of the corpus callosum, corona radiata, internal capsule, external capsule, superior longitudinal fasciculus and fronto-temporal WM regions showed significant negative correlations with scores of the treatment response. The current study suggests that the treatment response after paliperidone ER treatment may be associated with the fronto-temporo-limbic WM connectivity at early stage of treatment in patients with schizophrenia, and it could be used as a predictor of treatment response to paliperidone ER treatment after studies with large samples verify these results. PMID:26755544

  11. Social Subordination Stress and Serotonin Transporter Polymorphisms: Associations With Brain White Matter Tract Integrity and Behavior in Juvenile Female Macaques

    PubMed Central

    Howell, Brittany R.; Godfrey, Jodi; Gutman, David A.; Michopoulos, Vasiliki; Zhang, Xiaodong; Nair, Govind; Hu, Xiaoping; Wilson, Mark E.; Sanchez, Mar M.

    2014-01-01

    We examined the relationship between social rank and brain white matter (WM) microstructure, and socioemotional behavior, and its modulation by serotonin (5HT) transporter (5HTT) polymorphisms in prepubertal female macaques. Using diffusion tensor imaging and tract-based spatial statistics, social status differences were found in medial prefrontal cortex (mPFC) WM and cortico-thalamic tracts, with subordinates showing higher WM structural integrity (measured as fractional anisotropy, FA) than dominant animals. 5HTT genotype-related differences were detected in the posterior limb of the internal capsule, where s-variants had higher FA than l/l animals. Status by 5HTT interaction effects were found in (1) external capsule (middle longitudinal fasciculus), (2) parietal WM, and (3) short-range PFC tracts, with opposite effects in dominant and subordinate animals. In most regions showing FA differences, opposite differences were detected in radial diffusivity, but none in axial diffusivity, suggesting that differences in tract integrity likely involve differences in myelin. These findings highlight that differences in social rank are associated with differences in WM structural integrity in juveniles, particularly in tracts connecting prefrontal, sensory processing, motor and association regions, sometimes modulated by 5HTT genotype. Differences in these tracts were associated with increased emotional reactivity in subordinates, particularly with higher submissive and fear behaviors. PMID:23908263

  12. Abnormal White Matter Blood-Oxygen-Level-Dependent Signals in Chronic Mild Traumatic Brain Injury.

    PubMed

    Astafiev, Serguei V; Shulman, Gordon L; Metcalf, Nicholas V; Rengachary, Jennifer; MacDonald, Christine L; Harrington, Deborah L; Maruta, Jun; Shimony, Joshua S; Ghajar, Jamshid; Diwakar, Mithun; Huang, Ming-Xiong; Lee, Roland R; Corbetta, Maurizio

    2015-08-15

    Concussion, or mild traumatic brain injury (mTBI), can cause persistent behavioral symptoms and cognitive impairment, but it is unclear if this condition is associated with detectable structural or functional brain changes. At two sites, chronic mTBI human subjects with persistent post-concussive symptoms (three months to five years after injury) and age- and education-matched healthy human control subjects underwent extensive neuropsychological and visual tracking eye movement tests. At one site, patients and controls also performed the visual tracking tasks while blood-oxygen-level-dependent (BOLD) signals were measured with functional magnetic resonance imaging. Although neither neuropsychological nor visual tracking measures distinguished patients from controls at the level of individual subjects, abnormal BOLD signals were reliably detected in patients. The most consistent changes were localized in white matter regions: anterior internal capsule and superior longitudinal fasciculus. In contrast, BOLD signals were normal in cortical regions, such as the frontal eye field and intraparietal sulcus, that mediate oculomotor and attention functions necessary for visual tracking. The abnormal BOLD signals accurately differentiated chronic mTBI patients from healthy controls at the single-subject level, although they did not correlate with symptoms or neuropsychological performance. We conclude that subjects with persistent post-concussive symptoms can be identified years after their TBI using fMRI and an eye movement task despite showing normal structural MRI and DTI. PMID:25758167

  13. ADRB2, brain white matter integrity and cognitive ageing in the Lothian Birth Cohort 1936.

    PubMed

    Lyall, Donald M; Lopez, Lorna M; Bastin, Mark E; Maniega, Susana Muñoz; Penke, Lars; Valdés Hernández, Maria del C; Royle, Natalie A; Starr, John M; Porteous, David J; Wardlaw, Joanna M; Deary, Ian J

    2013-01-01

    The non-synonymous mutations arg16gly (rs1042713) and gln27glu (rs1042714) in the adrenergic ?-2 receptor gene (ADRB2) have been associated with cognitive function and brain white matter integrity. The current study aimed to replicate these findings and expand them to a broader range of cognitive and brain phenotypes. The sample used is a community-dwelling group of older people, the Lothian Birth Cohort 1936. They had been assessed cognitively at age 11 years, and undertook further cognitive assessments and brain diffusion MRI tractography in older age. The sample size range for cognitive function variables was N = 686-765, and for neuroimaging variables was N = 488-587. Previously-reported findings with these genetic variants did not replicate in this cohort. Novel, nominally significant associations were observed; notably, the integrity of the left arcuate fasciculus mediated the association between rs1042714 and the Digit Symbol Coding test of information processing speed. No significant associations of cognitive and brain phenotypes with ADRB2 variants survived correction for false discovery rate. Previous findings may therefore have been subject to type 1 error. Further study into links between ADRB2, cognitive function and brain white matter integrity is required. PMID:23229623

  14. The neural correlates of motor intentional disorders in patients with subcortical vascular cognitive impairment.

    PubMed

    Kim, Geon Ha; Seo, Sang Won; Jung, Kihyo; Kwon, Oh-Hun; Kwon, Hunki; Kim, Jong Hun; Roh, Jee Hoon; Kim, Min-Jeong; Lee, Byung Hwa; Yoon, Doo Sang; Hwang, Jung Won; Lee, Jong Min; Jeong, Jee Hyang; You, Heecheon; Heilman, Kenneth M; Na, Duk L

    2016-01-01

    Subcortical vascular cognitive impairment (SVCI) refers to cognitive impairment associated with small vessel disease. Motor intentional disorders (MID) have been reported in patients with SVCI. However, there are no studies exploring the neuroanatomical regions related to MID in SVCI patients. The aim of this study, therefore, was to investigate the neural correlates of MID in SVCI patients. Thirty-one patients with SVCI as well as 10 healthy match control participants were included. A "Pinch-Grip" apparatus was used to quantify the force control capabilities of the index finger in four different movement phases including initiation, development, maintenance, and termination. All participants underwent magnetic resonance imaging (MRI). Topographical cortical areas and white matter tracts correlated with the performances of the four different movement phases were assessed by the surface-based morphometry and tract-based spatial statistics analyses. Poorer performance in the maintenance task was related to cortical thinning in bilateral dorsolateral prefrontal, orbitofrontal and parietal cortices, while poorer performance in the termination task was associated with the disruption of fronto-parietal cortical areas as well as the white matter tracts including splenium and association fibers such as superior longitudinal fasciculus. Our study demonstrates that cortical areas and underlying white matter tracts associated with fronto-parietal attentional system play an important role in motor impersistence and perseveration in SVCI patients. PMID:26514838

  15. Right lateralized white matter abnormalities in first-episode, drug-naive paranoid schizophrenia.

    PubMed

    Guo, Wenbin; Liu, Feng; Liu, Zhening; Gao, Keming; Xiao, Changqing; Chen, Huafu; Zhao, Jingping

    2012-11-30

    Numerous studies in first-episode schizophrenia suggest the involvement of white matter (WM) abnormalities in multiple regions underlying the pathogenesis of this condition. However, there has never been a neuroimaging study in patients with first-episode, drug-naive paranoid schizophrenia by using tract-based spatial statistics (TBSS) method. Here, we used diffusion tensor imaging (DTI) with TBSS method to investigate the brain WM integrity in patients with first-episode, drug-naive paranoid schizophrenia. Twenty patients with first-episode, drug-naive paranoid schizophrenia and 26 healthy subjects matched with age, gender, and education level were scanned with DTI. An automated TBSS approach was employed to analyze the data. Voxel-wise statistics revealed that patients with paranoid schizophrenia had decreased fractional anisotropy (FA) values in the right superior longitudinal fasciculus (SLF) II, the right fornix, the right internal capsule, and the right external capsule compared to healthy subjects. Patients did not have increased FA values in any brain regions compared to healthy subjects. There was no correlation between the FA values in any brain regions and patient demographics and the severity of illness. Our findings suggest right-sided alterations of WM integrity in the WM tracts of cortical and subcortical regions may play an important role in the pathogenesis of paranoid schizophrenia. PMID:23022507

  16. Epidemiological and clinical aspects will guide the neuroimaging research in bipolar disorder.

    PubMed

    Houenou, J; Perlini, C; Brambilla, P

    2015-04-01

    Although neurobiological mechanisms of bipolar disorder (BD) are still unclear, neural models of the disease have recently been conceptualised thanks to neuroimaging. Indeed, magnetic resonance imaging (MRI) studies investigating structural and functional connectivity between different areas of the brain suggest an altered prefrontal-limbic coupling leading to disrupted emotional processing in BD, including uncinate fasciculus, amygdala, parahippocampal cortex, cingulate cortex as well corpus callosum. Specifically, these models assume an altered prefrontal control over a hyperactivity of the subcortical limbic structures implicated in automatic emotional processing. This impaired mechanism may finally trigger emotional hyper-reactivity and mood episodes. In this review, we first summarised some key neuroimaging studies on BD. In the second part of the work, we focused on the heterogeneity of the available studies. This variability is partly due to methodological factors (i.e., small sample size) and differences among studies (i.e., MRI acquisition and post-processing analyses) and partly to the clinical heterogeneity of BD. We finally outlined how epidemiological studies should indicate which risk factors and clinical dimensions of BD are relevant to be studied with neuroimaging in order to reduce heterogeneity and go beyond diagnostic categories. PMID:25592435

  17. Morphometry of Left Frontal and Temporal Poles Predicts Analogical Reasoning Abilities.

    PubMed

    Aichelburg, Clarisse; Urbanski, Marika; Thiebaut de Schotten, Michel; Humbert, Frederic; Levy, Richard; Volle, Emmanuelle

    2016-03-01

    Analogical reasoning is critical for making inferences and adapting to novelty. It can be studied experimentally using tasks that require creating similarities between situations or concepts, i.e., when their constituent elements share a similar organization or structure. Brain correlates of analogical reasoning have mostly been explored using functional imaging that has highlighted the involvement of the left rostrolateral prefrontal cortex (rlPFC) in healthy subjects. However, whether inter-individual variability in analogical reasoning ability in a healthy adult population is related to differences in brain architecture is unknown. We investigated this question by employing linear regression models of performance in analogy tasks and voxel-based morphometry in 54 healthy subjects. Our results revealed that the ability to reason by analogy was associated with structural variability in the left rlPFC and the anterior part of the inferolateral temporal cortex. Tractography of diffusion-weighted images suggested that these 2 regions have a different set of connections but may exchange information via the arcuate fasciculus. These results suggest that enhanced integrative and semantic abilities supported by structural variation in these areas (or their connectivity) may lead to more efficient analogical reasoning. PMID:25331605

  18. A combinatorial optogenetic approach to medial habenula function

    NASA Astrophysics Data System (ADS)

    Turner, Eric E.; Hsu, Yun-Wei; Wang, Si; Morton, Glenn; Zeng, Hongkui

    2013-03-01

    The habenula is a brain region found in all vertebrate species. It consists of medial and lateral subnuclei which make complex descending connections to the brainstem. Although the medial habenula (MHb) and its projection, the fasciculus retroflexus (FR), have been recognized for decades, their function remains obscure. The small size of the MHb in rodents, and the cellular and molecular complexity of this region, have made it difficult to study the function of this region with high specificity. Here we describe a Cre-mediated genetic system for expressing the microbial opsin channelrhodopsin (ChR2) specifically in the dorsal (dMHb) and ventral (vMHb) medial habenula. Genetically targeted expression of ChR2 allows MHb neurons to be selectively activated with light in acute brain slices with electrophysiological readouts, and in vivo by means of custom-built fiber optic cannulas. These tools will allow highly specific studies of MHb circuitry and the role of the MHb in behaviors related to addiction and mood regulation.

  19. A Comparison of Structural Brain Imaging Findings in Autism Spectrum Disorder and Attention-Deficit Hyperactivity Disorder.

    PubMed

    Dougherty, Chase C; Evans, David W; Myers, Scott M; Moore, Gregory J; Michael, Andrew M

    2016-03-01

    ASD and ADHD are regarded as distinct disorders in the current DSM-5. However, recent research and the RDoC initiative are recognizing considerable overlap in the clinical presentation of ASD, ADHD, and other neurodevelopmental disorders. In spite of numerous neuroimaging findings in ASD and ADHD, the extent to which either of the above views are supported remains equivocal. Here we compare structural MRI and DTI literature in ASD and ADHD. Our main findings reveal both distinct and shared neural features. Distinct expressions were in total brain volume (ASD: increased volume, ADHD: decreased volume), amygdala (ASD: overgrowth, ADHD: normal), and internal capsule (ASD: unclear, ADHD: reduced FA in DTI). Considerable overlap was noted in the corpus callosum and cerebellum (lower volume in structural MRI and decreased FA in DTI), and superior longitudinal fasciculus (reduced FA in DTI). In addition, we identify brain regions which have not been studied in depth and require more research. We discuss relationships between brain features and symptomatology. We conclude by addressing limitations of current neuroimaging research and offer approaches that account for clinical heterogeneity to better distinguish brain-behavior relationships. PMID:26482248

  20. Cryptic organisation within an apparently irregular rostrocaudal distribution of interneurons in the embryonic zebrafish spinal cord

    SciTech Connect

    Wells, Simon; The Special Research Centre for the Molecular Genetics of Development, University of Adelaide, Adelaide, South Australia 5005 ; Conran, John G.; Tamme, Richard; Gaudin, Arnaud; Webb, Jonathan; Lardelli, Michael; The Special Research Centre for the Molecular Genetics of Development, University of Adelaide, Adelaide, South Australia 5005

    2010-11-15

    The molecules and mechanisms involved in patterning the dorsoventral axis of the developing vertebrate spinal cord have been investigated extensively and many are well known. Conversely, knowledge of mechanisms patterning cellular distributions along the rostrocaudal axis is relatively more restricted. Much is known about the rostrocaudal distribution of motoneurons and spinal cord cells derived from neural crest but there is little known about the rostrocaudal patterning of most of the other spinal cord neurons. Here we report data from our analyses of the distribution of dorsal longitudinal ascending (DoLA) interneurons in the developing zebrafish spinal cord. We show that, although apparently distributed irregularly, these cells have cryptic organisation. We present a novel cell-labelling technique that reveals that DoLA interneurons migrate rostrally along the dorsal longitudinal fasciculus of the spinal cord during development. This cell-labelling strategy may be useful for in vivo analysis of factors controlling neuron migration in the central nervous system. Additionally, we show that DoLA interneurons persist in the developing spinal cord for longer than previously reported. These findings illustrate the need to investigate factors and mechanisms that determine 'irregular' patterns of cell distribution, particularly in the central nervous system but also in other tissues of developing embryos.

  1. Genetic dyslexia risk variant is related to neural connectivity patterns underlying phonological awareness in children.

    PubMed

    Skeide, Michael A; Kirsten, Holger; Kraft, Indra; Schaadt, Gesa; Müller, Bent; Neef, Nicole; Brauer, Jens; Wilcke, Arndt; Emmrich, Frank; Boltze, Johannes; Friederici, Angela D

    2015-09-01

    Phonological awareness is the best-validated predictor of reading and spelling skill and therefore highly relevant for developmental dyslexia. Prior imaging genetics studies link several dyslexia risk genes to either brain-functional or brain-structural factors of phonological deficits. However, coherent evidence for genetic associations with both functional and structural neural phenotypes underlying variation in phonological awareness has not yet been provided. Here we demonstrate that rs11100040, a reported modifier of SLC2A3, is related to the functional connectivity of left fronto-temporal phonological processing areas at resting state in a sample of 9- to 12-year-old children. Furthermore, we provide evidence that rs11100040 is related to the fractional anisotropy of the arcuate fasciculus, which forms the structural connection between these areas. This structural connectivity phenotype is associated with phonological awareness, which is in turn associated with the individual retrospective risk scores in an early dyslexia screening as well as to spelling. These results suggest a link between a dyslexia risk genotype and a functional as well as a structural neural phenotype, which is associated with a phonological awareness phenotype. The present study goes beyond previous work by integrating genetic, brain-functional and brain-structural aspects of phonological awareness within a single approach. These combined findings might be another step towards a multimodal biomarker for developmental dyslexia. PMID:26080313

  2. A review on functional and structural brain connectivity in numerical cognition.

    PubMed

    Moeller, Korbinian; Willmes, Klaus; Klein, Elise

    2015-01-01

    Only recently has the complex anatomo-functional system underlying numerical cognition become accessible to evaluation in the living brain. We identified 27 studies investigating brain connectivity in numerical cognition. Despite considerable heterogeneity regarding methodological approaches, populations investigated, and assessment procedures implemented, the results provided largely converging evidence regarding the underlying brain connectivity involved in numerical cognition. Analyses of both functional/effective as well as structural connectivity have consistently corroborated the assumption that numerical cognition is subserved by a fronto-parietal network including (intra)parietal as well as (pre)frontal cortex sites. Evaluation of structural connectivity has indicated the involvement of fronto-parietal association fibers encompassing the superior longitudinal fasciculus dorsally and the external capsule/extreme capsule system ventrally. Additionally, commissural fibers seem to connect the bilateral intraparietal sulci when number magnitude information is processed. Finally, the identification of projection fibers such as the superior corona radiata indicates connections between cortex and basal ganglia as well as the thalamus in numerical cognition. Studies on functional/effective connectivity further indicated a specific role of the hippocampus. These specifications of brain connectivity augment the triple-code model of number processing and calculation with respect to how gray matter areas associated with specific number-related representations may work together. PMID:26029075

  3. A Brain Network Processing the Age of Faces

    PubMed Central

    Homola, György A.; Jbabdi, Saad; Beckmann, Christian F.; Bartsch, Andreas J.

    2012-01-01

    Age is one of the most salient aspects in faces and of fundamental cognitive and social relevance. Although face processing has been studied extensively, brain regions responsive to age have yet to be localized. Using evocative face morphs and fMRI, we segregate two areas extending beyond the previously established face-sensitive core network, centered on the inferior temporal sulci and angular gyri bilaterally, both of which process changes of facial age. By means of probabilistic tractography, we compare their patterns of functional activation and structural connectivity. The ventral portion of Wernicke's understudied perpendicular association fasciculus is shown to interconnect the two areas, and activation within these clusters is related to the probability of fiber connectivity between them. In addition, post-hoc age-rating competence is found to be associated with high response magnitudes in the left angular gyrus. Our results provide the first evidence that facial age has a distinct representation pattern in the posterior human brain. We propose that particular face-sensitive nodes interact with additional object-unselective quantification modules to obtain individual estimates of facial age. This brain network processing the age of faces differs from the cortical areas that have previously been linked to less developmental but instantly changeable face aspects. Our probabilistic method of associating activations with connectivity patterns reveals an exemplary link that can be used to further study, assess and quantify structure-function relationships. PMID:23185334

  4. Patterns of gene expression associated with Pten deficiency in the developing inner ear.

    PubMed

    Kim, Hyung Jin; Ryu, Jihee; Woo, Hae-Mi; Cho, Samuel Sunghwan; Sung, Min Kyung; Kim, Sang Cheol; Park, Mi-Hyun; Park, Taesung; Koo, Soo Kyung

    2014-01-01

    In inner ear development, phosphatase and tensin homolog (PTEN) is necessary for neuronal maintenance, such as neuronal survival and accurate nerve innervations of hair cells. We previously reported that Pten conditional knockout (cKO) mice exhibited disorganized fasciculus with neuronal apoptosis in spiral ganglion neurons (SGNs). To better understand the genes and signaling networks related to auditory neuron maintenance, we compared the profiles of differentially expressed genes (DEGs) using microarray analysis of the inner ear in E14.5 Pten cKO and wild-type mice. We identified 46 statistically significant transcripts using significance analysis of microarrays, with the false-discovery rate set at 0%. Among the DEGs, expression levels of candidate genes and expression domains were validated by quantitative real-time RT-PCR and in situ hybridization, respectively. Ingenuity pathway analysis using DEGs identified significant signaling networks associated with apoptosis, cellular movement, and axon guidance (i.e., secreted phosphoprotein 1 (Spp1)-mediated cellular movement and regulator of G-protein signaling 4 (Rgs4)-mediated axon guidance). This result was consistent with the phenotypic defects of SGNs in Pten cKO mice (e.g., neuronal apoptosis, abnormal migration, and irregular nerve fiber patterns of SGNs). From this study, we suggest two key regulatory signaling networks mediated by Spp1 and Rgs4, which may play potential roles in neuronal differentiation of developing auditory neurons. PMID:24893171

  5. Structural correlates of subjective and objective memory performance in multiple sclerosis.

    PubMed

    Pardini, Matteo; Bergamino, Maurizio; Bommarito, Giulia; Bonzano, Laura; Luigi Mancardi, Gian; Roccatagliata, Luca

    2014-04-01

    Subjective and objective memory deficits represent a frequent and ill-understood aspect of multiple sclerosis (MS), and a significant cause of disability and quality of life reduction. The aim of the study is to verify the role of hippocampal and temporal associative fibers' damage in MS-related memory complaints. To reach this aim, 25 patients with low disability relapsing-remitting MS and 19 healthy controls were included in the study. All subjects underwent 3D T1 structural imaging and Diffusion Tensor Imaging. Additionally, MS patients underwent neuropsychological evaluation of objective (Selective Reminding Test and Spatial Recall Test) and of subjective (Perceived Deficit Questionnaire, Retrospective and Prospective Memory Subscales) memory deficits. Normalized hippocampal volume (NHV) and mean Fractional Anisotropy (FA) for the uncinate fasciculus (UF) and for the ventral division of the cingulum bundle (VCB) were calculated for all subjects. We showed that, compared to controls, MS subjects presented with reduced right NHV and with reduced mean FA bilaterally in the UF and the VCB. In the MS group, verbal memory scores correlated with left NHV, spatial memory scores correlated with right NHV, while perceived retrospective and prospective memory deficits correlated with left VCB and left UF mean FA respectively. Our data confirm an early involvement of memory-related brain structures in MS patients. Our data suggest that verbal and nonverbal memory as well as perceived retrospective and prospective memory deficits are related to alterations of discrete anatomical structures in the low-disability phase of MS. PMID:24375730

  6. Contemporary model of language organization: an overview for neurosurgeons.

    PubMed

    Chang, Edward F; Raygor, Kunal P; Berger, Mitchel S

    2015-02-01

    Classic models of language organization posited that separate motor and sensory language foci existed in the inferior frontal gyrus (Broca's area) and superior temporal gyrus (Wernicke's area), respectively, and that connections between these sites (arcuate fasciculus) allowed for auditory-motor interaction. These theories have predominated for more than a century, but advances in neuroimaging and stimulation mapping have provided a more detailed description of the functional neuroanatomy of language. New insights have shaped modern network-based models of speech processing composed of parallel and interconnected streams involving both cortical and subcortical areas. Recent models emphasize processing in "dorsal" and "ventral" pathways, mediating phonological and semantic processing, respectively. Phonological processing occurs along a dorsal pathway, from the posterosuperior temporal to the inferior frontal cortices. On the other hand, semantic information is carried in a ventral pathway that runs from the temporal pole to the basal occipitotemporal cortex, with anterior connections. Functional MRI has poor positive predictive value in determining critical language sites and should only be used as an adjunct for preoperative planning. Cortical and subcortical mapping should be used to define functional resection boundaries in eloquent areas and remains the clinical gold standard. In tracing the historical advancements in our understanding of speech processing, the authors hope to not only provide practicing neurosurgeons with additional information that will aid in surgical planning and prevent postoperative morbidity, but also underscore the fact that neurosurgeons are in a unique position to further advance our understanding of the anatomy and functional organization of language. PMID:25423277

  7. Language Laterality in Autism Spectrum Disorder and Typical Controls: A Functional, Volumetric, and Diffusion Tensor MRI Study

    PubMed Central

    Knaus, Tracey A.; Silver, Andrew M.; Kennedy, Meaghan; Lindgren, Kristen A.; Dominick, Kelli C.; Siegel, Jeremy; Tager-Flusberg, Helen

    2010-01-01

    Language and communication deficits are among the core features of autism spectrum disorder (ASD). Reduced or reversed asymmetry of language has been found in a number of disorders, including ASD. Studies of healthy adults have found an association between language laterality and anatomical measures but this has not been systematically investigated in ASD. The goal of this study was to examine differences in gray matter volume of perisylvian language regions, connections between language regions, and language abilities in individuals with typical left lateralized language compared to those with atypical (bilateral or right) asymmetry of language functions. 14 adolescent boys with ASD and 20 typically developing adolescent boys participated, including equal numbers of left- and right-handed individuals in each group. Participants with typical left lateralized language activation had smaller frontal language region volume and higher fractional anisotropy of the arcuate fasciculus compared to the group with atypical language laterality, across both ASD and control participants. The group with typical language asymmetry included the most right-handed controls and fewest left-handers with ASD. Atypical language laterality was more prevalent in the ASD than control group. These findings support an association between laterality of language function and language region anatomy. They also suggest anatomical differences may be more associated with variation in language laterality than specifically with ASD. Language laterality therefore may provide a novel way of subdividing samples, resulting in more homogenous groups for research into genetic and neurocognitive foundations of developmental disorders. PMID:20031197

  8. Longitudinal assessment of neuroanatomical and cognitive differences in young children with type 1 diabetes: association with hyperglycemia.

    PubMed

    Mauras, Nelly; Mazaika, Paul; Buckingham, Bruce; Weinzimer, Stuart; White, Neil H; Tsalikian, Eva; Hershey, Tamara; Cato, Allison; Cheng, Peiyao; Kollman, Craig; Beck, Roy W; Ruedy, Katrina; Aye, Tandy; Fox, Larry; Arbelaez, Ana Maria; Wilson, Darrell; Tansey, Michael; Tamborlane, William; Peng, Daniel; Marzelli, Matthew; Winer, Karen K; Reiss, Allan L

    2015-05-01

    Significant regional differences in gray and white matter volume and subtle cognitive differences between young diabetic and nondiabetic children have been observed. Here, we assessed whether these differences change over time and the relation with dysglycemia. Children ages 4 to <10 years with (n = 144) and without (n = 72) type 1 diabetes (T1D) had high-resolution structural MRI and comprehensive neurocognitive tests at baseline and 18 months and continuous glucose monitoring and HbA1c performed quarterly for 18 months. There were no differences in cognitive and executive function scores between groups at 18 months. However, children with diabetes had slower total gray and white matter growth than control subjects. Gray matter regions (left precuneus, right temporal, frontal, and parietal lobes and right medial-frontal cortex) showed lesser growth in diabetes, as did white matter areas (splenium of the corpus callosum, bilateral superior-parietal lobe, bilateral anterior forceps, and inferior-frontal fasciculus). These changes were associated with higher cumulative hyperglycemia and glucose variability but not with hypoglycemia. Young children with T1D have significant differences in total and regional gray and white matter growth in brain regions involved in complex sensorimotor processing and cognition compared with age-matched control subjects over 18 months, suggesting that chronic hyperglycemia may be detrimental to the developing brain. PMID:25488901

  9. Conduction aphasia with intact visual object naming.

    PubMed

    Pandey, Ajay Kumar; Heilman, Kenneth M

    2014-06-01

    Conduction aphasia, most often caused by damage to the inferior parietal lobe and arcuate fasciculus, is usually characterized by mildly dysfluent speech with frequent phonemic paraphasic errors, impaired repetition, and impaired word finding and naming, but with relatively spared comprehension. We report an 86-year-old right-handed man with conduction aphasia caused by an infarction that damaged his right temporoparietal region. On testing with the Western Aphasia Battery, however, he named objects almost perfectly. To test his naming ability further, we showed him half the items in the Boston Naming Test; we described or defined the other half of the items, but did not show them to the patient. He performed excellently when naming the objects that he could see, but he had difficulty naming the objects that were only described or defined. These observations suggest that visual word naming may be mediated by a network that is somewhat independent of the networks that mediate spontaneous word finding and word finding based on verbal descriptions or definitions. PMID:24968010

  10. Differential White Matter Connectivity in Early Mild Cognitive Impairment According to CSF Biomarkers

    PubMed Central

    Lim, Jae-Sung; Park, Young Ho; Jang, Jae-Won; Park, So Yong; Kim, SangYun

    2014-01-01

    Mild cognitive impairment (MCI) is a heterogeneous group and certain MCI subsets eventually convert to dementia. Cerebrospinal fluid (CSF) biomarkers are known to predict this conversion. We sought evidence for the differences in white matter connectivity between early amnestic MCI (EMCI) subgroups according to a CSF phosphorylated tau181p/amyloid beta1–42 ratio of 0.10. From the Alzheimer's Disease Neuroimaging Initiative database, 16 high-ratio, 25 low-ratio EMCI patients, and 20 normal controls with diffusion tensor images and CSF profiles were included. Compared to the high-ratio group, radial diffusivity significantly increased in both sides of the corpus callosum and the superior and inferior longitudinal fasciculus in the low-ratio group. In widespread white matter skeleton regions, the low-ratio group showed significantly increased mean, axial, and radial diffusivity compared to normal controls. However, the high-ratio group showed no differences when compared to the normal group. In conclusion, our study revealed that there were significant differences in white matter connectivity between EMCI subgroups according to CSF phosphorylated tau181p/amyloid beta1–42ratios. PMID:24614676

  11. White Matter Development in Early Puberty: A Longitudinal Volumetric and Diffusion Tensor Imaging Twin Study

    PubMed Central

    Brouwer, Rachel M.; Mandl, René C. W.; Schnack, Hugo G.; van Soelen, Inge L. C.; van Baal, G. Caroline; Peper, Jiska S.; Kahn, René S.; Boomsma, Dorret I.; Pol, H. E. Hulshoff

    2012-01-01

    White matter microstructure and volume show synchronous developmental patterns in children. White matter volume increases considerably during development. Fractional anisotropy, a measure for white matter microstructural directionality, also increases with age. Development of white matter volume and development of white matter microstructure seem to go hand in hand. The extent to which the same or different genetic and/or environmental factors drive these two aspects of white matter maturation is currently unknown. We mapped changes in white matter volume, surface area and diffusion parameters in mono- and dizygotic twins who were scanned at age 9 (203 individuals) and again at age 12 (126 individuals). Over the three-year interval, white matter volume (+6.0%) and surface area (+1.7%) increased, fiber bundles expanded (most pronounced in the left arcuate fasciculus and splenium), and fractional anisotropy increased (+3.0%). Genes influenced white matter volume (heritability ?85%), surface area (?85%), and fractional anisotropy (locally 7% to 50%) at both ages. Finally, volumetric white matter growth was negatively correlated with fractional anisotropy increase (r?=?–0.62) and this relationship was driven by environmental factors. In children who showed the most pronounced white matter growth, fractional anisotropy increased the least and vice-versa. Thus, white matter development in childhood may reflect a process of both expansion and fiber optimization. PMID:22514599

  12. Neural Correlates of Amusia in Williams Syndrome

    PubMed Central

    Lense, Miriam D.; Dankner, Nathan; Pryweller, Jennifer R.; Thornton-Wells, Tricia A.; Dykens, Elisabeth M.

    2014-01-01

    Congenital amusia is defined by marked deficits in pitch perception and production. Though historically examined only in otherwise typically developing (TD) populations, amusia has recently been documented in Williams syndrome (WS), a genetic, neurodevelopmental disorder with a unique auditory phenotype including auditory sensitivities and increased emotional responsiveness to music but variable musical skill. The current study used structural T1-weighted magnetic resonance imaging and diffusion tensor imaging to examine neural correlates of amusia in 17 individuals with WS (4 of whom met criteria for amusia). Consistent with findings from TD amusics, amusia in WS was associated with decreased fractional anisotropy (FA) in the right superior longitudinal fasciculus (SLF). The relationship between amusia and FA in the inferior component of the SLF was particularly robust, withstanding corrections for cognitive functioning, auditory sensitivities, or musical training. Though the number of individuals with amusia in the study is small, results add to evidence for the role of fronto-temporal disconnectivity in congenital amusia and suggest that novel populations with developmental differences can provide a window into understanding gene-brain-behavior relationships that underlie musical behaviors. PMID:25422929

  13. Localisation of motoneurons supplying the extra-ocular muscles of the rat using horseradish peroxidase and fluorescent double labelling.

    PubMed Central

    Labandeira Garcia, J L; Gomez Segade, L A; Suarez Nuñez, J M

    1983-01-01

    This paper describes a qualitative and quantitative investigation into the location of the motoneurons innervating the extra-ocular muscles of the rat. Injections of horseradish peroxidase, bisbenzimide, propidium iodide and DAPI-primuline were made either in one or simultaneously in two muscles. Unlike those of the cat, rabbit and monkey, the motoneurons which make up the oculomotor nucleus of the rat are not arranged in spatially separate subgroups belonging each to its corresponding extra-ocular muscle, but instead allow a high degree of superposition among the motor pools which they compose. The motoneurons innervating the lateral rectus and inferior oblique muscles are all homolateral; those of the medial and inferior rectus muscles are mainly homolateral with a few contralateral exceptions; and those of the superior rectus, levator palpebrae and superior oblique muscles are mainly contralateral with a small minority of homolateral exceptions. As well as from the main motor pools with which they are associated, the medial rectus, inferior rectus, superior rectus, levator palpebrae, superior oblique and lateral rectus muscles all receive innervation from motoneurons lying among the fibres of the fasciculus longitudinalis medialis. All these observations are supported by quantitative data. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 PMID:6195140

  14. White Matter Disease Contributes to Apathy and Disinhibition in Behavioral Variant Frontotemporal Dementia

    PubMed Central

    Powers, John P.; Massimo, Lauren; McMillan, Corey T.; Yushkevich, Paul A.; Zhang, Hui; Gee, James C.; Grossman, Murray

    2015-01-01

    Objective To relate changes in fractional anisotropy associated with behavioral variant frontotemporal dementia to measures of apathy and disinhibition. Background Apathy and disinhibition are the 2 most common behavioral features of behavioral variant frontotemporal dementia, and these symptoms are associated with accelerated patient decline and caregiver stress. However, little is known about how white matter disease contributes to these symptoms. Methods We collected neuropsychiatric data, volumetric magnetic resonance imaging, and diffusion-weighted imaging in 11 patients who met published criteria for behavioral variant frontotemporal dementia and had an autopsy-validated cerebrospinal fluid profile consistent with frontotemporal lobar degeneration. We also collected imaging data on 34 healthy seniors for analyses defining regions of disease in the patients. We calculated and analyzed fractional anisotropy with a white matter tract-specific method. This approach uses anatomically guided data reduction to increase sensitivity, and localizes results within canonically defined tracts. We used nonparametric, cluster-based statistical analysis to relate fractional anisotropy to neuropsychiatric measures of apathy and disinhibition. Results The patients with behavioral variant frontotemporal dementia had widespread reductions in fractional anisotropy in anterior portions of frontal and temporal white matter, compared to the controls. Fractional anisotropy correlated with apathy in the left uncinate fasciculus and with disinhibition in the right corona radiata. Conclusions In patients with behavioral variant frontotemporal dementia, apathy and disinhibition are associated with distinct regions of white matter disease. The implicated fiber tracts likely support frontotemporal networks that are involved in goal-directed behavior. PMID:25539040

  15. A dedicated visual pathway for prey detection in larval zebrafish

    PubMed Central

    Semmelhack, Julia L; Donovan, Joseph C; Thiele, Tod R; Kuehn, Enrico; Laurell, Eva; Baier, Herwig

    2014-01-01

    Zebrafish larvae show characteristic prey capture behavior in response to small moving objects. The neural mechanism used to recognize objects as prey remains largely unknown. We devised a machine learning behavior classification system to quantify hunting kinematics in semi-restrained animals exposed to a range of virtual stimuli. Two-photon calcium imaging revealed a small visual area, AF7, that was activated specifically by the optimal prey stimulus. This pretectal region is innervated by two types of retinal ganglion cells, which also send collaterals to the optic tectum. Laser ablation of AF7 markedly reduced prey capture behavior. We identified neurons with arbors in AF7 and found that they projected to multiple sensory and premotor areas: the optic tectum, the nucleus of the medial longitudinal fasciculus (nMLF) and the hindbrain. These findings indicate that computations in the retina give rise to a visual stream which transforms sensory information into a directed prey capture response. DOI: http://dx.doi.org/10.7554/eLife.04878.001 PMID:25490154

  16. An exploratory analysis linking neuropsychological testing to quantification of tractography using High Definition Fiber Tracking (HDFT) in military TBI.

    PubMed

    Presson, Nora; Beers, Sue R; Morrow, Lisa; Wagener, Lauren M; Bird, William A; Van Eman, Gina; Krishnaswamy, Deepa; Penderville, Joshua; Borrasso, Allison J; Benso, Steven; Puccio, Ava; Fissell, Catherine; Okonkwo, David O; Schneider, Walter

    2015-09-01

    To realize the potential value of tractography in traumatic brain injury (TBI), we must identify metrics that provide meaningful information about functional outcomes. The current study explores quantitative metrics describing the spatial properties of tractography from advanced diffusion imaging (High Definition Fiber Tracking, HDFT). In a small number of right-handed males from military TBI (N?=?7) and civilian control (N?=?6) samples, both tract homologue symmetry and tract spread (proportion of brain mask voxels contacted) differed for several tracts among civilian controls and extreme groups in the TBI sample (high scorers and low scorers) for verbal recall, serial reaction time, processing speed index, and trail-making. Notably, proportion of voxels contacted in the arcuate fasciculus distinguished high and low performers on the CVLT-II and PSI, potentially reflecting linguistic task demands, and GFA in the left corticospinal tract distinguished high and low performers in PSI and Trail Making Test Part A, potentially reflecting right hand motor response demands. The results suggest that, for advanced diffusion imaging, spatial properties of tractography may add analytic value to measures of tract anisotropy. PMID:25953056

  17. Impaired language pathways in tuberous sclerosis complex patients with autism spectrum disorders.

    PubMed

    Lewis, William W; Sahin, Mustafa; Scherrer, Benoit; Peters, Jurriaan M; Suarez, Ralph O; Vogel-Farley, Vanessa K; Jeste, Shafali S; Gregas, Matthew C; Prabhu, Sanjay P; Nelson, Charles A; Warfield, Simon K

    2013-07-01

    The purpose of this study was to examine the relationship between language pathways and autism spectrum disorders (ASDs) in patients with tuberous sclerosis complex (TSC). An advanced diffusion-weighted magnetic resonance imaging (MRI) was performed on 42 patients with TSC and 42 age-matched controls. Using a validated automatic method, white matter language pathways were identified and microstructural characteristics were extracted, including fractional anisotropy (FA) and mean diffusivity (MD). Among 42 patients with TSC, 12 had ASD (29%). After controlling for age, TSC patients without ASD had a lower FA than controls in the arcuate fasciculus (AF); TSC patients with ASD had even a smaller FA, lower than the FA for those without ASD. Similarly, TSC patients without ASD had a greater MD than controls in the AF; TSC patients with ASD had even a higher MD, greater than the MD in those without ASD. It remains unclear why some patients with TSC develop ASD, while others have better language and socio-behavioral outcomes. Our results suggest that language pathway microstructure may serve as a marker of the risk of ASD in TSC patients. Impaired microstructure in language pathways of TSC patients may indicate the development of ASD, although prospective studies of language pathway development and ASD diagnosis in TSC remain essential. PMID:22661408

  18. Associations of white matter integrity and cortical thickness in patients with schizophrenia and healthy controls.

    PubMed

    Ehrlich, Stefan; Geisler, Daniel; Yendiki, Anastasia; Panneck, Patricia; Roessner, Veit; Calhoun, Vince D; Magnotta, Vincent A; Gollub, Randy L; White, Tonya

    2014-05-01

    Typical brain development includes coordinated changes in both white matter (WM) integrity and cortical thickness (CT). These processes have been shown to be disrupted in schizophrenia, which is characterized by abnormalities in WM microstructure and by reduced CT. The aim of this study was to identify patterns of association between WM markers and cortex-wide CT in healthy controls (HCs) and patients with schizophrenia (SCZ). Using diffusion tensor imaging and structural magnetic resonance imaging data of the Mind Clinical Imaging Consortium study (130 HC and 111 SCZ), we tested for associations between (a) fractional anisotropy in selected manually labeled WM pathways (corpus callosum, anterior thalamic radiation, and superior longitudinal fasciculus) and CT, and (b) the number of lesion-like WM regions ("potholes") and CT. In HC, but not SCZ, we found highly significant negative associations between WM integrity and CT in several pathways, including frontal, temporal, and occipital brain regions. Conversely, in SCZ the number of WM potholes correlated with reduced CT in the left lateral temporal gyrus, left fusiform, and left lateral occipital brain area. Taken together, we found differential patterns of association between WM integrity and CT in HC and SCZ. Although the pattern in HC can be explained from a developmental perspective, the reduced gray matter CT in SCZ patients might be the result of focal but spatially heterogeneous disruptions of WM integrity. PMID:23661633

  19. Vasoactive intestinal peptide binding sites and fibers in the brain of the pigeon Columba livia: An autoradiographic and immunohistochemical study

    SciTech Connect

    Hof, P.R.; Dietl, M.M.; Charnay, Y.; Martin, J.L.; Bouras, C.; Palacios, J.M.; Magistretti, P.J. )

    1991-03-15

    The distribution of vasoactive intestinal peptide (VIP) binding sites in the pigeon brain was examined by in vitro autoradiography on slide-mounted sections. A fully characterized monoiodinated form of VIP, which maintains the biological activity of the native peptide, was used throughout this study. The highest densities of binding sites were observed in the hyperstriatum dorsale, archistriatum, auditory field L of neostriatum, area corticoidea dorsolateralis and temporo-parieto-occipitalis, area parahippocampalis, tectum opticum, nucleus dorsomedialis anterior thalami, and in the periventricular area of the hypothalamus. Lower densities of specific binding occurred in the neostriatum, hyperstriatum ventrale and nucleus septi lateralis, dorsolateral area of the thalamus, and lateral and posteromedial hypothalamus. Very low to background levels of VIP binding were detected in the ectostriatum, paleostriatum primitivum, paleostriatum augmentatum, lobus parolfactorius, nucleus accumbens, most of the brainstem, and the cerebellum. The distribution of VIP-containing fibers and terminals was examined by indirect immunofluorescence using a polyclonal antibody against porcine VIP. Fibers and terminals were observed in the area corticoidea dorsolateralis, area parahippocampalis, hippocampus, hyperstriatum accessorium, hyperstriatum dorsale, archistriatum, tuberculum olfactorium, nuclei dorsolateralis and dorsomedialis of the thalamus, and throughout the hypothalamus and the median eminence. Long projecting fibers were visualized in the tractus septohippocampalis. In the brainstem VIP immunoreactive fibers and terminals were observed mainly in the substantia grisea centralis, fasciculus longitudinalis medialis, lemniscus lateralis, and in the area surrounding the nuclei of the 7th, 9th, and 10th cranial nerves.

  20. Deviant white matter structure in adults with attention-deficit/hyperactivity disorder points to aberrant myelination and affects neuropsychological performance.

    PubMed

    Onnink, A Marten H; Zwiers, Marcel P; Hoogman, Martine; Mostert, Jeanette C; Dammers, Janneke; Kan, Cornelis C; Vasquez, Alejandro Arias; Schene, Aart H; Buitelaar, Jan; Franke, Barbara

    2015-12-01

    Attention-deficit/hyperactivity disorder (ADHD) in childhood is characterized by gray and white matter abnormalities in several brain areas. Considerably less is known about white matter microstructure in adults with ADHD and its relation with clinical symptoms and cognitive performance. In 107 adult ADHD patients and 109 gender-, age- and IQ-matched controls, we used diffusion tensor imaging (DTI) with tract-based spatial statistics (TBSS) to investigate whole-skeleton changes of fractional anisotropy (FA) and mean, axial, and radial diffusivity (MD, AD, RD). Additionally, we studied the relation of FA and MD values with symptom severity and cognitive performance on tasks measuring working memory, attention, inhibition, and delay discounting. In comparison to controls, participants with ADHD showed reduced FA in corpus callosum, bilateral corona radiata, and thalamic radiation. Higher MD and RD were found in overlapping and even more widespread areas in both hemispheres, also encompassing internal and external capsule, sagittal stratum, fornix, and superior lateral fasciculus. Values of FA and MD were not associated with symptom severity. However, within some white matter clusters that distinguished patients from controls, worse inhibition performance was associated with reduced FA and more impulsive decision making was associated with increased MD. This study shows widespread differences in white matter integrity between adults with persistent ADHD and healthy individuals. Changes in RD suggest aberrant myelination as a pathophysiological factor in persistent ADHD. The microstructural differences in adult ADHD may contribute to poor inhibition and greater impulsivity but appear to be independent of disease severity. PMID:25956761

  1. Associations of White Matter Integrity and Cortical Thickness in Patients With Schizophrenia and Healthy Controls

    PubMed Central

    Ehrlich, Stefan

    2014-01-01

    Typical brain development includes coordinated changes in both white matter (WM) integrity and cortical thickness (CT). These processes have been shown to be disrupted in schizophrenia, which is characterized by abnormalities in WM microstructure and by reduced CT. The aim of this study was to identify patterns of association between WM markers and cortex-wide CT in healthy controls (HCs) and patients with schizophrenia (SCZ). Using diffusion tensor imaging and structural magnetic resonance imaging data of the Mind Clinical Imaging Consortium study (130 HC and 111 SCZ), we tested for associations between (a) fractional anisotropy in selected manually labeled WM pathways (corpus callosum, anterior thalamic radiation, and superior longitudinal fasciculus) and CT, and (b) the number of lesion-like WM regions (“potholes”) and CT. In HC, but not SCZ, we found highly significant negative associations between WM integrity and CT in several pathways, including frontal, temporal, and occipital brain regions. Conversely, in SCZ the number of WM potholes correlated with reduced CT in the left lateral temporal gyrus, left fusiform, and left lateral occipital brain area. Taken together, we found differential patterns of association between WM integrity and CT in HC and SCZ. Although the pattern in HC can be explained from a developmental perspective, the reduced gray matter CT in SCZ patients might be the result of focal but spatially heterogeneous disruptions of WM integrity. PMID:23661633

  2. Degradation of cognitive timing mechanisms in behavioural variant frontotemporal dementia

    PubMed Central

    Henley, Susie M.D.; Downey, Laura E.; Nicholas, Jennifer M.; Kinnunen, Kirsi M.; Golden, Hannah L.; Buckley, Aisling; Mahoney, Colin J.; Crutch, Sebastian J.

    2014-01-01

    The current study examined motor timing in frontotemporal dementia (FTD), which manifests as progressive deterioration in social, behavioural and cognitive functions. Twenty-patients fulfilling consensus clinical criteria for behavioural variant FTD (bvFTD), 11 patients fulfilling consensus clinical criteria for semantic-variant primary progressive aphasia (svPPA), four patients fulfilling criteria for nonfluent/agrammatic primary progressive aphasia (naPPA), eight patients fulfilling criteria for Alzheimer?s disease (AD), and 31 controls were assessed on both an externally- and self-paced finger-tapping task requiring maintenance of a regular, 1500 ms beat over 50 taps. Grey and white matter correlates of deficits in motor timing were examined using voxel-based morphometry (VBM) and diffusion tensor imaging (DTI). bvFTD patients exhibited significant deficits in aspects of both externally- and self-paced tapping. Increased mean inter-response interval (faster than target tap time) in the self-paced task was associated with reduced grey matter volume in the cerebellum bilaterally, right middle temporal gyrus, and with increased axial diffusivity in the right superior longitudinal fasciculus, regions and tracts which have been suggested to be involved in a subcortical–cortical network of structures underlying timing abilities. This suggests that such structures can be affected in bvFTD, and that impaired motor timing may underlie some characteristics of the bvFTD phenotype. PMID:25447066

  3. Body representations in the human brain revealed by kinesthetic illusions and their essential contributions to motor control and corporeal awareness.

    PubMed

    Naito, Eiichi; Morita, Tomoyo; Amemiya, Kaoru

    2016-03-01

    The human brain can generate a continuously changing postural model of our body. Somatic (proprioceptive) signals from skeletal muscles and joints contribute to the formation of the body representation. Recent neuroimaging studies of proprioceptive bodily illusions have elucidated the importance of three brain systems (motor network, specialized parietal systems, right inferior fronto-parietal network) in the formation of the human body representation. The motor network, especially the primary motor cortex, processes afferent input from skeletal muscles. Such information may contribute to the formation of kinematic/dynamic postural models of limbs, thereby enabling fast online feedback control. Distinct parietal regions appear to play specialized roles in the transformation/integration of information across different coordinate systems, which may subserve the adaptability and flexibility of the body representation. Finally, the right inferior fronto-parietal network, connected by the inferior branch of the superior longitudinal fasciculus, is consistently recruited when an individual experiences various types of bodily illusions and its possible roles relate to corporeal awareness, which is likely elicited through a series of neuronal processes of monitoring and accumulating bodily information and updating the body representation. Because this network is also recruited when identifying one's own features, the network activity could be a neuronal basis for self-consciousness. PMID:26562333

  4. The role of the habenula in drug addiction

    PubMed Central

    Velasquez, Kenia M.; Molfese, David L.; Salas, Ramiro

    2014-01-01

    Interest in the habenula has greatly increased in recent years. The habenula is a small brain structure located posterior to the thalamus and adjacent to the third ventricle. Despite its small size, the habenula can be divided into medial habenula (MHb) and lateral habenula (LHb) nuclei that are anatomically and transcriptionally distinct. The habenula receives inputs from the limbic system and basal ganglia primarily via the stria medullaris. The fasciculus retroflexus is the primary habenular output from the habenula to the midbrain and governs release of glutamate onto gabaergic cells in the rostromedial tegmental nucleus (RMTg) and onto the interpeduncular nucleus. The resulting GABA released from RMTg neurons inactivates dopaminergic cells in the ventral tegmental area/substantia nigra compacta. Through this process, the habenula controls dopamine levels in the striatum. Thus, the habenula plays a critical role in reward and reward-associated learning. The LHb also modulates serotonin levels and norepinephrine release, while the MHb modulates acetylcholine. The habenula is a critical crossroad that influences the brain’s response to pain, stress, anxiety, sleep, and reward. Dysfunction of the habenula has been linked to depression, schizophrenia, and the effects of drugs of abuse. This review focuses on the possible relationships between the habenula and drug abuse. PMID:24734015

  5. Language Dysfunction After Stroke and Damage to White Matter Tracts Evaluated Using Diffusion Tensor Imaging

    PubMed Central

    Breier, J.I.; Hasan, K.M.; Zhang, W.; Men, D.; Papanicolaou, A.C.

    2011-01-01

    BACKGROUND AND PURPOSE Knowledge of the anatomic basis of aphasia after stroke has both theoretic and clinical implications by informing models of cortical connectivity and providing data for diagnosis and prognosis. In this study we use diffusion tensor imaging to address the relationship between damage to specific white matter tracts and linguistic deficits after left hemisphere stroke. MATERIALS AND METHODS Twenty patients aged 38–77 years with a history of stroke in the left hemisphere underwent diffusion tensor imaging, structural MR imaging, and language testing. All of the patients were premorbidly right handed and underwent imaging and language testing at least 1 month after stroke. RESULTS Lower fractional anisotropy (FA) values in the superior longitudinal and arcuate fasciculi of the left hemisphere, an indication of greater damage to these tracts, were correlated with decreased ability to repeat spoken language. Comprehension deficits after stroke were associated with lower FA values in the arcuate fasciculus of the left hemisphere. The findings for repetition were independent of MR imaging ratings of the degree of damage to cortical areas of the left hemisphere involved in language function. There were no findings for homotopic tracts in the right hemisphere. CONCLUSION This study provides support for a specific role for damage to the superior longitudinal and arcuate fasciculi in the left hemisphere in patients with deficits in repetition of speech in aphasia after stroke. PMID:18039757

  6. A review on functional and structural brain connectivity in numerical cognition

    PubMed Central

    Moeller, Korbinian; Willmes, Klaus; Klein, Elise

    2015-01-01

    Only recently has the complex anatomo-functional system underlying numerical cognition become accessible to evaluation in the living brain. We identified 27 studies investigating brain connectivity in numerical cognition. Despite considerable heterogeneity regarding methodological approaches, populations investigated, and assessment procedures implemented, the results provided largely converging evidence regarding the underlying brain connectivity involved in numerical cognition. Analyses of both functional/effective as well as structural connectivity have consistently corroborated the assumption that numerical cognition is subserved by a fronto-parietal network including (intra)parietal as well as (pre)frontal cortex sites. Evaluation of structural connectivity has indicated the involvement of fronto-parietal association fibers encompassing the superior longitudinal fasciculus dorsally and the external capsule/extreme capsule system ventrally. Additionally, commissural fibers seem to connect the bilateral intraparietal sulci when number magnitude information is processed. Finally, the identification of projection fibers such as the superior corona radiata indicates connections between cortex and basal ganglia as well as the thalamus in numerical cognition. Studies on functional/effective connectivity further indicated a specific role of the hippocampus. These specifications of brain connectivity augment the triple-code model of number processing and calculation with respect to how gray matter areas associated with specific number-related representations may work together. PMID:26029075

  7. The localization of vagal neurons in the terrapin (Trionyx sinensis) as revealed by the retrograde horseradish peroxidase method.

    PubMed

    Leong, S K; Tay, S W; Wong, W C

    1984-12-01

    After the application of horseradish peroxidase in Nonidet P40 solution to the right cervical vagus in the terrapin, the neurons giving origin to efferent fibers and the transganglionic sensory fibres are labeled. The neurons forming the vagus nerve at the mid-cervical level are located in the dorsal motor nucleus of the vagus nerve (DMX), in the nucleus ambiguus (NA), in an area located ventral to the DMX, and less definitely in the nucleus of the spinal accessory nerve. The DMX and NA neurons are bilaterally distributed with a predominant ipsilateral component. Labeled DMX neurons appear to have a slightly more extensive distribution than those in mammals and their dendrites extend to the nucleus of the tractus solitarius, hypoglossal nucleus (HN), lateral wall and floor of the 4th ventricle and a region dorsomedial to the HN. Some recurrent collaterals of the DMX neurons loop round the medial longitudinal fasciculus to end in a region immediately ventrolateral to the DMX. Transganglionic sensory fibers course with the tractus solitarius and spinal tract of the trigeminal nerve to end in the respective nucleus associated with the tract. PMID:6512177

  8. Axonal trajectories of inhibitory vestibulocollic neurons activated by the anterior semicircular canal nerve and their synaptic effects on neck motoneurons in the cat.

    PubMed

    Uchino, Y; Isu, N; Sakuma, A; Ichikawa, T; Hiranuma, K

    1990-01-01

    Somatic location, axonal trajectories and synaptic effects of inhibitory vestibulocollic neurons which were activated by selective stimulation of the anterior semicircular canal nerve (ACN) were studied in the anesthetized cat. ACN stimulation evoked disynaptic inhibitory postsynaptic potentials (IPSPs) in neck flexor motoneurons. This was seen in all the (64/64) tested motoneurons innervating the ipsilateral (i-) longus capitis (LC) and the i-sternocleidomastoideus (SCM) muscles and in 86% (38/44) of the motoneurons innervating the contralateral (c-) LC muscle. The inhibitory relay neurons, identified by orthodromic and antidromic responses to stimulation of the ACN and the i- and c-LC motoneuron pools, were classified as VCi (vestibulocollic neurons sending an axon to the i-LC motoneuron pool) and VCc (vestibulocollic neurons sending an axon to the c-LC motoneuron pool) neurons. Neither VCi nor VCc neurons were activated antidromically by localized stimulation of the ascending medial longitudinal fasciculus (asc. MLF) or the 3rd nuclei. They were located in the medial, descending and ventral lateral vestibular nuclei. It was also observed that VCi neurons produced unitary IPSPs in i-LC and i-SCM motoneurons in the C1 segment. Inhibitory synapses were estimated to be on the cell somata and/or the proximal dendrites of the motoneurons. PMID:2257898

  9. Medial vestibulospinal tract lesions impair sacculo-collic reflexes.

    PubMed

    Kim, Seonhye; Lee, Hak-Seung; Kim, Ji Soo

    2010-05-01

    The medial vestibulospinal tract (VST) is known to mediate the vestibular-evoked myogenic potential (VEMP) in the contracting sternocleidomastoid muscle (SCM). To determine whether disruption of the medial VST in the medulla impairs formation of VEMP, we measured VEMP in 14 patients with medial medullary infarction (MMI). VEMP was induced by a short tone burst and was recorded in contracting SCM while patients turned their heads forcefully to the contralateral side against resistance. Normative data were obtained from 47 healthy volunteers. Seven patients (50%) had abnormal VEMP in the side of the MMI lesion, absent in two, decreased in four, and delayed in two. One patient showed both decreased and delayed response. Of the seven patients with abnormal VEMP, five had the lesions that extended to the dorsal tegmentum while five of the seven patients with normal VEMP showed restricted anteromedial lesions mainly involving the pyramids. Spontaneous nystagmus (4/7, 57%), gaze-evoked nystagmus (6/7, 86%), and ocular tilt reaction/tilt of the subjective visual vertical (4/7, 57%) were frequently observed in the patients with abnormal VEMP. The abnormal VEMP in patients with infarctions involving the medullary tegmentum supports that VEMP is mediated by the medial VST descending within the medial longitudinal fasciculus. PMID:20054695

  10. New Burgess shale type fauna in the Middle Cambrian Stephen Formation on Mt. Stephen, British Columbia

    SciTech Connect

    Collins, D.H.

    1985-01-01

    Excavation of a fossil locality discovered in 1981 on Mount Stephen, 5 km south of the Burgess shale site on Mount Wapta, has yielded about 1000 specimens of a new soft-bodied and lightly-sclerotized fauna. The fauna includes the trilobite, Glossopleura, which is characteristic of the lower part of the Stephen Formation, 100 m or more stratigraphically below the level of the Burgess shale fauna. The arthropod, Alalcomenaeus, a genus extremely rare in the Burgess shale, is by far the most numerous, followed by a new, fishlike arthropod with prominent eyes, and Branchiocaris, another extremely rare Burgess shale arthropod. Many Burgess shale animals are present, although the most common, Marrella, is absent. They include the arthropods Canadaspis, Naraoia, Plenocaris and Tuzoia, the worms Ottoia and Burgessochaeta, the onychophoran Aysheaia, the sponge Leptomitus, Wiwaxia of unknown affinities, and Fasciculus, a possible ctenophore. The Glossopleura fauna thus adds extant and extinct invertebrate groups to those already known in the Middle Cambrian epoch, mostly from the Burgess shale. It also demonstrates that the animals preserved in the Stephen Formation are evolutionarily stable.

  11. F-Spondin/spon1b Expression Patterns in Developing and Adult Zebrafish

    PubMed Central

    Akle, Veronica; Guelin, Emmanuel; Yu, Lili; Brassard-Giordano, Helena; Slack, Barbara E.; Zhdanova, Irina V.

    2012-01-01

    F-spondin, an extracellular matrix protein, is an important player in embryonic morphogenesis and CNS development, but its presence and role later in life remains largely unknown. We generated a transgenic zebrafish in which GFP is expressed under the control of the F-spondin (spon1b) promoter, and used it in combination with complementary techniques to undertake a detailed characterization of the expression patterns of F-spondin in developing and adult brain and periphery. We found that F-spondin is often associated with structures forming long neuronal tracts, including retinal ganglion cells, the olfactory bulb, the habenula, and the nucleus of the medial longitudinal fasciculus (nMLF). F-spondin expression coincides with zones of adult neurogenesis and is abundant in CSF-contacting secretory neurons, especially those in the hypothalamus. Use of this new transgenic model also revealed F-spondin expression patterns in the peripheral CNS, notably in enteric neurons, and in peripheral tissues involved in active patterning or proliferation in adults, including the endoskeleton of zebrafish fins and the continuously regenerating pharyngeal teeth. Moreover, patterning of the regenerating caudal fin following fin amputation in adult zebrafish was associated with F-spondin expression in the blastema, a proliferative region critical for tissue reconstitution. Together, these findings suggest major roles for F-spondin in the CNS and periphery of the developing and adult vertebrate. PMID:22768035

  12. White matter structural integrity differs between people with schizophrenia and healthy groups as a function of cognitive control.

    PubMed

    Schaeffer, David J; Rodrigue, Amanda L; Burton, Courtney R; Pierce, Jordan E; Unsworth, Nash; Clementz, Brett A; McDowell, Jennifer E

    2015-12-01

    A behavioral hallmark of schizophrenia is poor cognitive control. Recent evidence suggests that problems with cognitive control in schizophrenia are related to disconnectivity along major white matter fibers. Although deficits of cognitive control are common in schizophrenia, a proportion of otherwise healthy subjects show poor cognitive control performance. The present study sought to address this potential confound by comparing white matter integrity between a group with schizophrenia and otherwise healthy individuals with either high or low levels of cognitive control (based on working memory span performance). Diffusion tensor imaging was used to evaluate white matter integrity in 24 participants with schizophrenia, 24 healthy participants with high cognitive control (HCC), and 25 healthy participants with low cognitive control (LCC). To test for differences in fractional anisotropy (FA) across major white matter fiber tracts, a voxelwise region of interest analysis was conducted in standardized brain space. In a separate analysis, regions of interest were manually drawn in native brain space to isolate superior longitudinal fasciculus (SLF), a tract implicated in cognitive control performance. The voxelwise analysis demonstrated widespread lower FA in the schizophrenia group compared to the HCC group. With a high degree of concordance, the manual ROI analysis revealed lower FA in the schizophrenia group compared to the HCC group. Taken together, these results provide evidence to suggest that structural differences identified between healthy groups and schizophrenia may not be entirely specific to the disease process and can vary as a function of cognitive control capacity in the comparison group. PMID:26585221

  13. White matter abnormalities of microstructure and physiological noise in schizophrenia.

    PubMed

    Cheng, Hu; Newman, Sharlene D; Kent, Jerillyn S; Bolbecker, Amanda; Klaunig, Mallory J; O'Donnell, Brian F; Puce, Aina; Hetrick, William P

    2015-12-01

    White matter abnormalities in schizophrenia have been revealed by many imaging techniques and analysis methods. One of the findings by diffusion tensor imaging is a decrease in fractional anisotropy (FA), which is an indicator of white matter integrity. On the other hand, elevation of metabolic rate in white matter was observed from positron emission tomography (PET) studies. In this report, we aim to compare the two structural and functional effects on the same subjects. Our comparison is based on the hypothesis that signal fluctuation in white matter is associated with white matter functional activity. We examined the variance of the signal in resting state fMRI and found significant differences between individuals with schizophrenia and non-psychiatric controls specifically in white matter tissue. Controls showed higher temporal signal-to-noise ratios clustered in regions including temporal, frontal, and parietal lobes, cerebellum, corpus callosum, superior longitudinal fasciculus, and other major white matter tracts. These regions with higher temporal signal-to-noise ratio agree well with those showing higher metabolic activity reported by studies using PET. The results suggest that individuals with schizophrenia tend to have higher functional activity in white matter in certain brain regions relative to healthy controls. Despite some overlaps, the distinct regions for physiological noise are different from those for FA derived from diffusion tensor imaging, and therefore provide a unique angle to explore potential mechanisms to white matter abnormality. PMID:25560665

  14. Methadone-induced Damage to White Matter Integrity in Methadone Maintenance Patients: A Longitudinal Self-control DTI Study

    PubMed Central

    Li, Wei; Li, Qiang; Wang, Yarong; Zhu, Jia; Ye, Jianjun; Yan, Xuejiao; Li, Yongbin; Chen, Jiajie; Liu, Jierong; Li, Zhe; Wang, Wei; Liu, Yijun

    2016-01-01

    Methadone maintenance treatment (MMT) can induce impairments in brain function and structure, despite its clinical effectiveness. However, the effect of chronic MMT on brain white matter (WM) is not fully known. Thirty-three MMT patients underwent diffusion tensor imaging (DTI) twice – at the start of the study (Scan1) and one year later (Scan2). Tract-based spatial statistics were used to investigate changes in fractional anisotropy (FA), axial diffusivity (AD) and radial diffusivity (RD) between the two scans. The correlations between DTI indices and methadone consumption and neuropsychological status were analysed. We found significantly decreased FA, decreased AD and increased RD in Scan2 in extensive WM regions; overlapping regions were found in the left posterior limb and the retrolenticular part of internal capsule, superior and posterior corona radiata, bilateral external capsule and the right superior longitudinal fasciculus. In addition, the change of FA in the overlapping regions was positively correlated with the accumulated dosage of methadone use, the RD value in Scan2 and non-planning impulsiveness (NPI) measured at follow-up. The results suggest that methadone has damaging effects on WM integrity. The dose-dependent pattern and characteristics of the impairment may suggest new strategies for MMT. PMID:26794650

  15. Descending control of swim posture by a midbrain nucleus in zebrafish

    PubMed Central

    Thiele, Tod R; Donovan, Joseph C; Baier, Herwig

    2014-01-01

    The reticular formation in the brainstem controls motor output via axonal projections to the hindbrain and spinal cord. It remains unclear how individual groups of brainstem neurons contribute to specific motor functions. Here, we investigate the behavioral role of the nucleus of the medial longitudinal fasciculus (nMLF), a small group of reticulospinal neurons in the zebrafish midbrain. Calcium imaging revealed that nMLF activity is correlated with bouts of swimming. Optogenetic stimulation of neurons in the left or right nMLF activates the posterior hypaxial muscle and produces a graded ipsilateral tail deflection. Unilateral ablation of a subset of nMLF cells biases the tail position to the intact side during visually evoked swims, while sparing other locomotor maneuvers. We conclude that activity in the nMLF provides postural control of tail orientation and thus steers the direction of swimming. Our studies provide an example of fine-grained modularity of descending motor control in vertebrates. PMID:25066082

  16. Limb apraxia in a patient with cerebral infarct: diffusion tensor tractography study.

    PubMed

    Hong, Ji Heon; Lee, Jun; Cho, Yoon Woo; Byun, Woo Mok; Cho, Hee Kyung; Son, Su Min; Jang, Sung Ho

    2012-01-01

    We report on a patient with ideomotor apraxia (IMA) and limb-kinetic apraxia (LKA) following cerebral infarct, which demonstrated neural tract injuries by diffusion tensor tractography (DTT). A 67-year-old male was diagnosed as cerebral infarct in the left frontal cortex (anterior portion of the precentral gyrus and prefrontal cortex) and centrum semiovale. The patient presented with severe paralysis of the right upper extremity and mild weakness of the right lower extremity at onset. At the time of DTT scanning (5 months after onset), the patient was able to move all joint muscles of the right upper extremity against gravity, except for the finger extensors, which he could extend partially against gravity. The patient showed intact ideational plan for motor performance; however, his movements were slow, clumsy, and mutilated when executing grasp-release movements of his affected hand. The patient's score on the ideomotor apraxia test was 20 (cut-off score < 32). DTTs for premotor cortex fibers, supplementary motor area fibers, and superior longitudinal fasciculus of the left hemisphere showed partial injuries, compared with those of the right side, and these injuries appeared to be responsible for IMA and LKA in this patient. PMID:22672938

  17. The Simplified Reference Tissue Model with 18F-fallypride PET: Choice of Reference Region

    PubMed Central

    Ishibashi, Kenji; Robertson, Chelsea L.; Mandelkern, Mark A.; Morgan, Andrew T.; London, Edythe D.

    2014-01-01

    The development of high-affinity radiotracers for positron emission tomography has allowed for quantification of dopamine receptors in extrastriatal as well as striatal regions of brain. As these new radiotracers have distinctly different kinetic properties than their predecessors, it is important to examine the suitability of kinetic models to represent their uptake, distribution and in vivo washout. Using the simplified reference tissue model, we investigated the influence of reference region choice on striatal binding potential (BPND) of 18F-fallypride, a high-affinity dopamine D2/D3 receptor ligand. We compared visual cortex and a white matter region (superior longitudinal fasciculus) to the cerebellum, a commonly used reference tissue, in a PET-fallypride study of healthy and methamphetamine-dependent subjects. Compared to cerebellum, use of visual cortex produced significantly greater sample variance in BPND. Use of the white matter region was associated with BPND values and sample variance similar to those obtained with cerebellum, and a larger effect size for the group differences in striatal BPND between healthy and methamphetamine-dependent subjects. Our results do not support the use of visual cortex as a reference region in 18F-fallypride studies, and suggest that white matter may be a reasonable alternative to cerebellum as it displays similar statistical and kinetic properties. PMID:24447617

  18. The Role of Low and High Spatial Frequencies in Exogenous Attention to Biologically Salient Stimuli

    PubMed Central

    Carretié, Luis; Ríos, Marcos; Periáñez, José A.; Kessel, Dominique; Álvarez-Linera, Juan

    2012-01-01

    Exogenous attention can be understood as an adaptive tool that permits the detection and processing of biologically salient events even when the individual is engaged in a resource-consuming task. Indirect data suggest that the spatial frequency of stimulation may be a crucial element in this process. Behavioral and neural data (both functional and structural) were analyzed for 36 participants engaged in a digit categorization task in which distracters were presented. Distracters were biologically salient or anodyne images, and had three spatial frequency formats: intact, low spatial frequencies only, and high spatial frequencies only. Behavior confirmed enhanced exogenous attention to biologically salient distracters. The activity in the right and left intraparietal sulci and the right middle frontal gyrus was associated with this behavioral pattern and was greater in response to salient than to neutral distracters, the three areas presenting strong correlations to each other. Importantly, the enhanced response of this network to biologically salient distracters with respect to neutral distracters relied on low spatial frequencies to a significantly greater extent than on high spatial frequencies. Structural analyses suggested the involvement of internal capsule, superior longitudinal fasciculus and corpus callosum in this network. Results confirm that exogenous attention is preferentially captured by biologically salient information, and suggest that the architecture and function underlying this process are low spatial frequency-biased. PMID:22590649

  19. Early maturation of the linguistic dorsal pathway in human infants.

    PubMed

    Leroy, François; Glasel, Hervé; Dubois, Jessica; Hertz-Pannier, Lucie; Thirion, Bertrand; Mangin, Jean-François; Dehaene-Lambertz, Ghislaine

    2011-01-26

    Human infants, unlike even closely related primates, exhibit a remarkable capacity for language learning. Yet how the underlying anatomical network matures remains largely unknown. The classical view is that of a largely immature brain comprising only a few islands of maturity in primary cortices. This view has favored a description of learning based on bottom-up algorithms and has tended to discard the role of frontal regions, which were assumed to be barely functional early on. Here, using an index based on the normalized T2-weighted magnetic resonance signal, we have quantified maturation within the linguistic network in fourteen 1- to 4-month-old infants. Our results show first that the ventral superior temporal sulcus (STS), and not the inferior frontal area, is the less mature perisylvian region. A significant difference of maturation in the STS favoring the right side is an early testimony of the distinctive left-right development of this structure observed during the whole life. Second, asymmetries of maturation in Broca's area were correlated with asymmetries in the posterior STS and in the parietal segment of the arcuate fasciculus, suggesting that an efficient frontotemporal dorsal pathway might provide infants with a phonological loop circuitry much earlier than expected. PMID:21273434

  20. A Brain Centred View of Psychiatric Comorbidity in Tinnitus: From Otology to Hodology

    PubMed Central

    Minichino, Amedeo; Panico, Roberta; Testugini, Valeria; Altissimi, Giancarlo; Cianfrone, Giancarlo

    2014-01-01

    Introduction. Comorbid psychiatric disorders are frequent among patients affected by tinnitus. There are mutual clinical influences between tinnitus and psychiatric disorders, as well as neurobiological relations based on partially overlapping hodological and neuroplastic phenomena. The aim of the present paper is to review the evidence of alterations in brain networks underlying tinnitus physiopathology and to discuss them in light of the current knowledge of the neurobiology of psychiatric disorders. Methods. Relevant literature was identified through a search on Medline and PubMed; search terms included tinnitus, brain, plasticity, cortex, network, and pathways. Results. Tinnitus phenomenon results from systemic-neurootological triggers followed by neuronal remapping within several auditory and nonauditory pathways. Plastic reorganization and white matter alterations within limbic system, arcuate fasciculus, insula, salience network, dorsolateral prefrontal cortex, auditory pathways, ffrontocortical, and thalamocortical networks are discussed. Discussion. Several overlapping brain network alterations do exist between tinnitus and psychiatric disorders. Tinnitus, initially related to a clinicoanatomical approach based on a cortical localizationism, could be better explained by an holistic or associationist approach considering psychic functions and tinnitus as emergent properties of partially overlapping large-scale neural networks. PMID:25018882

  1. Disruption of structural connectivity along the dorsal and ventral language pathways in patients with nonfluent and semantic variant primary progressive aphasia: a DT MRI study and a literature review.

    PubMed

    Agosta, Federica; Galantucci, Sebastiano; Canu, Elisa; Cappa, Stefano F; Magnani, Giuseppe; Franceschi, Massimo; Falini, Andrea; Comi, Giancarlo; Filippi, Massimo

    2013-11-01

    Nonfluent (NFV) and semantic (SV) variants of primary progressive aphasia (PPA) are associated with distinct patterns of focal cortical atrophy and underlying pathology. Previous diffusion tensor (DT) MRI studies showed a more ventral white matter (WM) involvement in SV patients and a more widespread frontal involvement in NFV. Aim of this manuscript is twofold. First, we wished to provide a brief state-of-the-art review on WM damage in PPA. Second, we used DT MRI to assess the topography of WM microstructural damage along dorsal and ventral language pathways and corpus callosum in patients with NFV and SV. Our findings show that the two PPA variants share an overlapping pattern of dorsal and ventral pathway abnormalities. In addition to these common abnormalities, variant-specific WM changes were also found, with NFV patients having a more severe damage to the dorsal (fronto-parietal) WM connections within the left superior longitudinal fasciculus/arcuate and SV patients showing a greater left ventral tract involvement (inferior longitudinal and uncinate fasciculi). These findings offer evidence that both dorsal and ventral language networks may contribute to the relatively selective deficits in NFV and SV patients. PMID:23890877

  2. Multiple Indices of Diffusion Identifies White Matter Damage in Mild Cognitive Impairment and Alzheimer’s Disease

    PubMed Central

    O'Dwyer, Laurence; Lamberton, Franck; Bokde, Arun L. W.; Ewers, Michael; Faluyi, Yetunde O.; Tanner, Colby; Mazoyer, Bernard; O'Neill, Des; Bartley, Máiréad; Collins, D. Rónán; Coughlan, Tara; Prvulovic, David; Hampel, Harald

    2011-01-01

    The study of multiple indices of diffusion, including axial (DA), radial (DR) and mean diffusion (MD), as well as fractional anisotropy (FA), enables WM damage in Alzheimer's disease (AD) to be assessed in detail. Here, tract-based spatial statistics (TBSS) were performed on scans of 40 healthy elders, 19 non-amnestic MCI (MCIna) subjects, 14 amnestic MCI (MCIa) subjects and 9 AD patients. Significantly higher DA was found in MCIna subjects compared to healthy elders in the right posterior cingulum/precuneus. Significantly higher DA was also found in MCIa subjects compared to healthy elders in the left prefrontal cortex, particularly in the forceps minor and uncinate fasciculus. In the MCIa versus MCIna comparison, significantly higher DA was found in large areas of the left prefrontal cortex. For AD patients, the overlap of FA and DR changes and the overlap of FA and MD changes were seen in temporal, parietal and frontal lobes, as well as the corpus callosum and fornix. Analysis of differences between the AD versus MCIna, and AD versus MCIa contrasts, highlighted regions that are increasingly compromised in more severe disease stages. Microstructural damage independent of gross tissue loss was widespread in later disease stages. Our findings suggest a scheme where WM damage begins in the core memory network of the temporal lobe, cingulum and prefrontal regions, and spreads beyond these regions in later stages. DA and MD indices were most sensitive at detecting early changes in MCIa. PMID:21738785

  3. Dissociable morphometric profiles of the affective and cognitive dimensions of alexithymia.

    PubMed

    van der Velde, Jorien; van Tol, Marie-José; Goerlich-Dobre, Katharina Sophia; Gromann, Paula M; Swart, Marte; de Haan, Lieuwe; Wiersma, Durk; Bruggeman, Richard; Krabbendam, Lydia; Aleman, André

    2014-05-01

    Alexithymia ("no words for feelings") is a psychological construct that can be divided in a cognitive and affective dimension. The cognitive dimension reflects the ability to identify, verbalize and analyze feelings, whereas the affective dimension reflects the degree to which individuals get aroused by emotional stimuli and their ability to fantasize. These two alexithymia dimensions may differentially put individuals at risk to develop psychopathology. However, their neural correlates have rarely been investigated. The aim of the current study was to investigate whether the cognitive and affective alexithymia dimension are associated with unique anatomical profiles. Structural MRI scans of 57 participants (29 males; mean age: 34) were processed using a voxel-based morphometry (VBM) - Diffeomorphic Anatomical Registration Through Exponentiated Lie algebra (DARTEL) approach. Multiple regression analyses were performed to examine the common and specific associations between gray and white matter volume and alexithymia subdimensions. The results revealed that the cognitive dimension was related to lower dorsal anterior cingulate volume. In contrast, the affective alexithymia was associated with lower gray matter volume in the medial orbitofrontal cortex (OFC) and lower white matter volume in the superior longitudinal fasciculus (SLF) near the angular gyrus. No relationship between corpus callosum volume and alexithymia was observed. These results are consistent with the idea that there are two separable neural systems underlying alexithymia. This finding might encourage future research into the link between specific alexithymia subtypes and the development of psychopathology. PMID:24699037

  4. Robust and efficient linear registration of white-matter fascicles in the space of streamlines.

    PubMed

    Garyfallidis, Eleftherios; Ocegueda, Omar; Wassermann, Demian; Descoteaux, Maxime

    2015-08-15

    The neuroscientific community today is very much interested in analyzing specific white matter bundles like the arcuate fasciculus, the corticospinal tract, or the recently discovered Aslant tract to study sex differences, lateralization and many other connectivity applications. For this reason, experts spend time manually segmenting these fascicles and bundles using streamlines obtained from diffusion MRI tractography. However, to date, there are very few computational tools available to register these fascicles directly so that they can be analyzed and their differences quantified across populations. In this paper, we introduce a novel, robust and efficient framework to align bundles of streamlines directly in the space of streamlines. We call this framework Streamline-based Linear Registration. We first show that this method can be used successfully to align individual bundles as well as whole brain streamlines. Additionally, if used as a piecewise linear registration across many bundles, we show that our novel method systematically provides higher overlap (Jaccard indices) than state-of-the-art nonlinear image-based registration in the white matter. We also show how our novel method can be used to create bundle-specific atlases in a straightforward manner and we give an example of a probabilistic atlas construction of the optic radiation. In summary, Streamline-based Linear Registration provides a solid registration framework for creating new methods to study the white matter and perform group-level tractometry analysis. PMID:25987367

  5. Diffusion Tensor Imaging Parameters in Mild Traumatic Brain Injury and Its Correlation with Early Neuropsychological Impairment: A Longitudinal Study

    PubMed Central

    Narayanan, Vairavan; Kuo, Tan Li; Delano-Wood, Lisa; Chinna, Karuthan; Bondi, Mark William; Waran, Vicknes; Ganesan, Dharmendra; Ramli, Norlisah

    2015-01-01

    Abstract We explored the prognostic value of diffusion tensor imaging (DTI) parameters of selected white matter (WM) tracts in predicting neuropsychological outcome, both at baseline and 6 months later, among well-characterized patients diagnosed with mild traumatic brain injury (mTBI). Sixty-one patients with mTBI (mean age=27.08; standard deviation [SD], 8.55) underwent scanning at an average of 10 h (SD, 4.26) post-trauma along with assessment of their neuropsychological performance at an average of 4.35 h (SD, 7.08) upon full Glasgow Coma Scale recovery. Results were then compared to 19 healthy control participants (mean age=29.05; SD, 5.84), both in the acute stage and 6 months post-trauma. DTI and neuropsychological measures between acute and chronic phases were compared, and significant differences emerged. Specifically, chronic-phase fractional anisotropy and radial diffusivity values showed significant group differences in the corona radiata, anterior limb of internal capsule, cingulum, superior longitudinal fasciculus, optic radiation, and genu of corpus callosum. Findings also demonstrated associations between DTI indices and neuropsychological outcome across two time points. Our results provide new evidence for the use of DTI as an imaging biomarker and indicator of WM damage occurring in the context of mTBI, and they underscore the dynamic nature of brain injury and possible biological basis of chronic neurocognitive alterations. PMID:25952562

  6. Neuroanatomical correlates of negative emotionality-related traits: A systematic review and meta-analysis.

    PubMed

    Mincic, Adina M

    2015-10-01

    Two central traits present in the most influential models of personality characterize the response to positive and, respectively, negative emotional events. Negative emotionality (NE)-related traits are linked to vulnerability to mood and anxiety disorders; this has fuelled a special interest in examining stable differences in brain morphology associated to these traits. Structural imaging methods including voxel-based morphometry, cortical thickness analysis and diffusion tensor imaging (DTI) have yielded inconclusive and sometimes contradictory results. This review summarizes the findings reported to date through these methods and discusses them in relation to the functional imaging results. To detect topographic convergence between studies showing positive and, respectively, negative grey matter associations with NE-traits, activation likelihood estimation (ALE) meta-analyses of VBM studies were performed. Individuals scoring high on NE-related traits show consistent morphological differences in a left-lateralized circuit: higher grey matter volume (GMV) in amygdala and anterior parahippocampal gyrus and lower GMV in the orbitofrontal cortex extending into perigenual anterior cingulate cortex. Most DTI studies indicate reduced white matter integrity in various brain regions and tracts, particularly in the uncinate fasciculus and in cingulum bundle. These results show that the behavioural phenotype associated to NE traits is reflected in structural differences within the cortico-limbic system, suggesting alterations in information processing and transmission. The results are discussed from the perspective of neuron-glia interactions. Future directions are outlined based on recent developments in structural imaging techniques. PMID:26265397

  7. Integrated miRNA-mRNA analysis in the habenula nuclei of mice intravenously self-administering nicotine

    PubMed Central

    Lee, Sangjoon; Woo, Jiwan; Kim, Yong Sik; Im, Heh-In

    2015-01-01

    A considerable amount of evidence suggests that microRNAs (miRNAs) play crucial roles in the neuroadaptation of drug addiction. Habenula (Hb), one of the critical brain regions involved in reward and addiction, can be divided into two anatomically and transcriptionally distinct regions: medial habenula (MHb) and lateral habenula (LHb) nuclei. However, very few studies have compared the functional roles of these regions. Here, by using mirConnX integrator and KEGG pathway mapping, we simultaneously analysed the differential expression patterns of miRNAs and messenger RNA (mRNA) within MHb and LHb under nicotine addiction. Significantly altered miRNAs and mRNAs were found in the Hb of mice intravenously self-administering nicotine. Interestingly, some miRNAs were oppositely regulated between the MHb and the LHb, and their potential targets included various genes of cell signalling pathways related to the degeneration of fasciculus retroflexus (FR). This study provides an improved insight into the differential regulation of habenular transcripts in nicotine addiction, as well as the potential functions of miRNAs in several biological pathways involved in the nicotine addiction. PMID:26260614

  8. [Enzyme histochemical study of the brain of Chthonerpeton indistinctum (Gymnophiona, Amphibia)].

    PubMed

    Welsch, U; Tan, S H

    1979-01-01

    In the brain of the Caecilian species Chthonerpeton indistinctum the following enzymes have been demonstrated by means of histochemical techniques: acid phosphatase, alpha-naphthylacetate esterase, acetylcholin esterase. Acid phosphatase occurs in the cytoplasm of the neurons in 4 different types of localization. Its activity in the ventral parts of the brain is markedly higher than in the dorsal ones. Of particularly high activity are: the motor neurons in the tegmentum, the nucleus mesencephali trigemini, individual large neurons in the marginal zone of the grey matter of the telencephalon, which seems to be a special character of the Caecilians among the Amphibia. The ependyma exhibits local differences in respect of acid phosphatase activity. alpha-Naphthylacetate esterase marks in particular the secretory neurons of the hypothalamus, the large perikarya of the nucleus mesencephali trigemini and the motor neurons of the tegmentum. In the telencephalon the alpha-naphthylacetate esterase activity corresponds to that of acid phosphatase. Acetylcholin esterase marks--with certain restrictions--cholinergic neurons. These predominate in Chthonerpeton in the caudal parts of the brain. In the telencephalon amygdala, septal area striatum and the mitral cells are of comparatively high activity. The neurosecretory neurons of the hypothalamus are particularly rich in this enzyme. As an anurans the cholinergic fasciculus retroflexus as asymmetric. The tectum opticum is of secondary simplicity and does not exhibit a clearly recognizable stratification. PMID:524986

  9. Whole brain functional connectivity using phase locking measures of resting state magnetoencephalography

    PubMed Central

    Schmidt, Benjamin T.; Ghuman, Avniel S.; Huppert, Theodore J.

    2014-01-01

    The analysis of spontaneous functional connectivity (sFC) reveals the statistical connections between regions of the brain consistent with underlying functional communication networks within the brain. In this work, we describe the implementation of a complete all-to-all network analysis of resting state neuronal activity from magnetoencephalography (MEG). Using graph theory to define networks at the dipole level, we established functionally defined regions by k-means clustering cortical surface locations using Eigenvector centrality (EVC) scores from the all-to-all adjacency model. Permutation testing was used to estimate regions with statistically significant connections compared to empty room data, which adjusts for spatial dependencies introduced by the MEG inverse problem. In order to test this model, we performed a series of numerical simulations investigating the effects of the MEG reconstruction on connectivity estimates. We subsequently applied the approach to subject data to investigate the effectiveness of our method in obtaining whole brain networks. Our findings indicated that our model provides statistically robust estimates of functional region networks. Application of our phase locking network methodology to real data produced networks with similar connectivity to previously published findings, specifically, we found connections between contralateral areas of the arcuate fasciculus that have been previously investigated. The use of data-driven methods for neuroscientific investigations provides a new tool for researchers in identifying and characterizing whole brain functional connectivity networks. PMID:25018690

  10. Brain regional lesion burden and impaired mobility in the elderly

    PubMed Central

    Moscufo, Nicola; Guttmann, Charles R.G.; Meier, Dominik; Csapo, Istvan; Hildenbrand, Peter G.; Healy, Brian C.; Schmidt, Julia A.; Wolfson, Leslie

    2009-01-01

    This study investigated the relationship of brain white matter (WM) lesions affecting specific neural networks with decreased mobility in ninety-nine healthy community-dwelling subjects ?75-years old prospectively enrolled by age and mobility status. We assessed lesion burden in the genu, body and splenium of corpus callosum; anterior, superior and posterior corona radiata; anterior and posterior limbs of internal capsule; corticospinal tract; and superior longitudinal fasciculus. Burden in the splenium of corpus callosum (SCC) demonstrated the highest correlation particularly with walking speed (r=0.4, p<10?4), and in logistic regression it was the best regional predictor of low mobility performance. We also found that independent of mobility, corona radiata has the largest lesion burden with anterior (ACR) and posterior (PCR) aspects being the most frequently affected. The results suggest that compromised inter-hemispheric integration of visuospatial information through the SCC plays an important role in mobility impairment in the elderly. The relatively high lesion susceptibility of ACR and PCR in all subjects may obscure the importance of these lesions in mobility impairment. PMID:19428145

  11. Music Making as a Tool for Promoting Brain Plasticity across the Life Span

    PubMed Central

    Wan, Catherine Y.; Schlaug, Gottfried

    2010-01-01

    Playing a musical instrument is an intense, multisensory, and motor experience that usually commences at an early age and requires the acquisition and maintenance of a range of skills over the course of a musician's lifetime. Thus, musicians offer an excellent human model for studying the brain effects of acquiring specialized sensorimotor skills. For example, musicians learn and repeatedly practice the association of motor actions with specific sound and visual patterns (musical notation) while receiving continuous multisensory feedback. This association learning can strengthen connections between auditory and motor regions (e.g., arcuate fasciculus) while activating multimodal integration regions (e.g., around the intraparietal sulcus). We argue that training of this neural network may produce cross-modal effects on other behavioral or cognitive operations that draw on this network. Plasticity in this network may explain some of the sensorimotor and cognitive enhancements that have been associated with music training. These enhancements suggest the potential for music making as an interactive treatment or intervention for neurological and developmental disorders, as well as those associated with normal aging. PMID:20889966

  12. [Visualization of Gray Matter Myelin and Fiber Bundles Critical for Relative Pitch: A Role of the Left Posterior Long Insular Cortex].

    PubMed

    Shimizu, Yuichiro; Sakai, Kuniyoshi L

    2015-09-01

    Relative pitch is the ability to identify a tone pitch based on external or internal pitches. Here we used magnetic resonance imaging (MRI) to determine which cortical region is responsible for relative pitch. Forty-eight participants were asked to listen to 24 piano tones, and then write down the names of the tones (except reference tones of a(1)=440 Hz, which were intermittently presented three times). We classified the participants into three groups based on their task scores: Group A (n=12, full points), Group B (n=22, 6-20 points), and Group C (n=14, 0-5 points). We focused on the myelin of the gray matter, which can be visualized by the ratio of MR signals from a pair of T(1)- and T(2)-weighted images. We found significantly increased ratios in the left posterior long insular cortex for Group A. We also observed more consistent pathways in the anterior region of the left middle longitudinal fasciculus for Group A compared to Group C, which passed through the left superior temporal gyrus. Because these regions are involved in the processing of speech sounds, the present results suggest that the ability to identify musical pitches is associated with universal linguistic abilities. PMID:26329156

  13. Research with transcranial magnetic stimulation in the treatment of aphasia.

    PubMed

    Martin, Paula I; Naeser, Margaret A; Ho, Michael; Treglia, Ethan; Kaplan, Elina; Baker, Errol H; Pascual-Leone, Alvaro

    2009-11-01

    Repetitive transcranial magnetic stimulation (rTMS) has been used to improve language behavior, including naming, in stroke patients with chronic, nonfluent aphasia. Part 1 of this article reviews functional imaging studies related to language recovery in aphasia. Part 2 reviews the rationale for using rTMS to treat nonfluent aphasia (based on functional imaging) and presents our current rTMS protocol. We present language results from our rTMS studies as well as imaging results from overt naming functional MRI scans obtained before and after a series of rTMS treatments. Part 3 presents results from a pilot study in which rTMS treatments were followed immediately by constraint-induced language therapy. Part 4 reviews our diffusion tensor imaging study examining the possible connectivity of the arcuate fasciculus to different parts of Broca's area (pars triangularis, pars opercularis) and to the ventral premotor cortex. The potential role of mirror neurons in the right pars opercularis and ventral premotor cortex in aphasia recovery is discussed. PMID:19818232

  14. Research with rTMS in the treatment of aphasia.

    PubMed

    Naeser, Margaret A; Martin, Paula I; Treglia, Ethan; Ho, Michael; Kaplan, Elina; Bashir, Shahid; Hamilton, Roy; Coslett, H Branch; Pascual-Leone, Alvaro

    2010-01-01

    This review of our research with rTMS to treat aphasia contains four parts: Part 1 reviews functional brain imaging studies related to recovery of language in aphasia with emphasis on nonfluent aphasia. Part 2 presents the rationale for using rTMS to treat nonfluent aphasia patients (based on results from functional imaging studies). Part 2 also reviews our current rTMS treatment protocol used with nonfluent aphasia patients, and our functional imaging results from overt naming fMRI scans, obtained pre- and post- a series of rTMS treatments. Part 3 presents results from a pilot study where rTMS treatments were followed immediately by constraint-induced language therapy (CILT). Part 4 reviews our diffusion tensor imaging (DTI) study that examined white matter connections between the horizontal, midportion of the arcuate fasciculus (hAF) to different parts within Broca's area (pars triangularis, PTr; pars opercularis, POp), and the ventral premotor cortex (vPMC) in the RH and in the LH. Part 4 also addresses some of the possible mechanisms involved with improved naming and speech, following rTMS with nonfluent aphasia patients. PMID:20714075

  15. Musicians and music making as a model for the study of brain plasticity

    PubMed Central

    Schlaug, Gottfried

    2015-01-01

    Playing a musical instrument is an intense, multisensory, and motor experience that usually commences at an early age and requires the acquisition and maintenance of a range of sensory and motor skills over the course of a musician’s lifetime. Thus, musicians offer an excellent human model for studying behavioral-cognitive as well as brain effects of acquiring, practicing, and maintaining these specialized skills. Research has shown that repeatedly practicing the association of motor actions with specific sound and visual patterns (musical notation), while receiving continuous multisensory feedback will strengthen connections between auditory and motor regions (e.g., arcuate fasciculus) as well as multimodal integration regions. Plasticity in this network may explain some of the sensorimotor and cognitive enhancements that have been associated with music training. Furthermore, the plasticity of this system as a result of long term and intense interventions suggest the potential for music making activities (e.g., forms of singing) as an intervention for neurological and developmental disorders to learn and relearn associations between auditory and motor functions such as vocal motor functions. PMID:25725909

  16. White matter abnormalities of microstructure and physiological noise in schizophrenia

    PubMed Central

    Newman, Sharlene D.; Kent, Jerillyn S.; Bolbecker, Amanda; Klaunig, Mallory J.; O'Donnell, Brian F.; Puce, Aina; Hetrick, William P.

    2015-01-01

    White matter abnormalities in schizophrenia have been revealed by many imaging techniques and analysis methods. One of the findings by diffusion tensor imaging is a decrease in fractional anisotropy (FA), which is an indicator of white matter integrity. On the other hand, elevation of metabolic rate in white matter was observed from positron emission tomography (PET) studies. In this report, we aim to compare the two structural and functional effects on the same subjects. Our comparison is based on the hypothesis that signal fluctuation in white matter is associated with white matter functional activity. We examined the variance of the signal in resting state fMRI and found significant differences between individuals with schizophrenia and non-psychiatric controls specifically in white matter tissue. Controls showed higher temporal signal-to-noise ratios clustered in regions including temporal, frontal, and parietal lobes, cerebellum, corpus callosum, superior longitudinal fasciculus, and other major white matter tracts. These regions with higher temporal signal-to-noise ratio agree well with those showing higher metabolic activity reported by studies using PET. The results suggest that individuals with schizophrenia tend to have higher functional activity in white matter in certain brain regions relative to healthy controls. Despite some overlaps, the distinct regions for physiological noise are different from those for FA derived from diffusion tensor imaging, and therefore provide a unique angle to explore potential mechanisms to white matter abnormality. PMID:25560665

  17. L2-Proficiency-Dependent Laterality Shift in Structural Connectivity of Brain Language Pathways.

    PubMed

    Xiang, Huadong; van Leeuwen, Tessa Marije; Dediu, Dan; Roberts, Leah; Norris, David G; Hagoort, Peter

    2015-08-01

    Diffusion tensor imaging (DTI) and a longitudinal language learning approach were applied to investigate the relationship between the achieved second language (L2) proficiency during L2 learning and the reorganization of structural connectivity between core language areas. Language proficiency tests and DTI scans were obtained from German students before and after they completed an intensive 6-week course of the Dutch language. In the initial learning stage, with increasing L2 proficiency, the hemispheric dominance of the Brodmann area (BA) 6-temporal pathway (mainly along the arcuate fasciculus) shifted from the left to the right hemisphere. With further increased proficiency, however, lateralization dominance was again found in the left BA6-temporal pathway. This result is consistent with reports in the literature that imply a stronger involvement of the right hemisphere in L2 processing especially for less proficient L2 speakers. This is the first time that an L2 proficiency-dependent laterality shift in the structural connectivity of language pathways during L2 acquisition has been observed to shift from left to right and back to left hemisphere dominance with increasing L2 proficiency. The authors additionally find that changes in fractional anisotropy values after the course are related to the time elapsed between the two scans. The results suggest that structural connectivity in (at least part of) the perisylvian language network may be subject to fast dynamic changes following language learning. PMID:25594261

  18. Descending neural projections to the spinal cord in the channel catfish, Ictalurus punctatus.

    PubMed

    New, J G; Snyder, B D; Woodson, K L

    1998-10-01

    Retrograde transport of horseradish peroxidase was used to determine the descending projections to the spinal cord in an otophysan fish, the channel catfish, Ictalurus punctatus. The majority of cells projecting to the spinal cord are located in the reticular formation, which is organized into rhombomeric segments. Vestibulospinal neurons are located in the descending, magnocellular, and tangential octaval nuclei, as well as in the medial octavolateralis nucleus of the lateral line system. Cells in the facial lobe project to the spinal cord. Additionally, axons of cells of the trigeminal system and the nucleus of the lateral lemniscus project caudally into the spinal cord. In the midbrain, descending spinal projections arise from cells of the medial longitudinal fasciculus and the red nucleus. More rostrally, cells of the ventrolateral thalamus, dorsal periventricular hypothalamus, central pretectal and magnocellular preoptic nuclei also project to the cord. The results of this study indicate that there are a number of homologies in the descending systems of bony fishes and other vertebrate taxa, including tetrapods. We also provide further evidence that a red nucleus is present in the brains of bony fishes and is therefore a primitive vertebrate character antedating the evolution of tetrapods. PMID:9776078

  19. Emotion regulation deficits in euthymic bipolar I versus bipolar II disorder: a functional and diffusion-tensor imaging study

    PubMed Central

    Caseras, Xavier; Murphy, Kevin; Lawrence, Natalia S; Fuentes-Claramonte, Paola; Watts, Jessica; Jones, Derek K; Phillips, Mary L

    2015-01-01

    Objectives Emotion regulation deficits are a core feature of bipolar disorder. However, their potential neurobiological underpinnings and existence beyond bipolar I disorder remain unexplored. Our main goal was to investigate whether both individuals with bipolar I and bipolar II disorder show deficits in emotion regulation during an attention control task, and to explore the neurophysiological underpinnings of this potential deficit. Methods Twenty healthy controls, 16 euthymic participants with bipolar I disorder, and 19 euthymic participants with bipolar II disorder completed psychometric and clinical assessments, a neuroimaging emotion regulation paradigm, and an anatomical diffusion-weighted scan. Groups were matched for age, gender, and verbal IQ. Results During the presence of emotional distracters, subjects with bipolar I disorder showed slowed reaction times to targets, and increased blood oxygenation level-dependent (BOLD) responses in the amygdala, accumbens, and dorsolateral prefrontal cortex, but not increased inverse functional connectivity between these prefrontal and subcortical areas, and altered white matter microstructure organization in the right uncinate fasciculus. Subjects with bipolar II disorder showed no altered reaction times, increased BOLD responses in the same brain areas, increased inverse functional connectivity between the prefrontal cortex and amygdala, and no abnormalities in white matter organization. Conclusions Participants with bipolar I disorder showed abnormalities in functional and anatomical connectivity between prefrontal cortices and subcortical structures in emotion regulation circuitry. However, these deficits did not extend to subjects with bipolar II disorder, suggesting fundamental differences in the pathophysiology of bipolar disorder subtypes. PMID:25771686

  20. O5.01STANDARDS AND ADVANCED TESTING FOR INTRAOPERATIVE LANGUAGE AND COGNITIVE MAPPING

    PubMed Central

    Comi, A.; Riva, M.; Casarotti, A.; Fava, E.; Pessina, F.; Papagno, C.; Bello, L.

    2014-01-01

    Resection of tumors involving language pathways requires the intraoperative identification of cortical and subcortical sites mediating the various language components, which determines the extent of resection (EOR). One of the critical point is which test(s) has to be performed during subcortical mapping. Object naming is the most used one, but it may have the limit to miss other components of language such as verb naming and generation, or comprehension of words or sentences, potentially resulting in permanent post operative deficits. Patients can be submitted intraoperatively to complex batteries of tests, resulting in limited performance and high chance of intraoperative fatigue, resulting in poor mapping. We revised our experience on subcortical language mapping in a series of patients with language pathways gliomas, in which two strategies for subcortical mapping were applied: in a first group only naming was used; in the second group, object naming was prevalently used but integrated with other tests (verb naming and generation, comprehension of words or sentences, number recognition and calculation). Results were evaluated as immediate and permanent deficits by applying a large neuropsychological testing, and as EOR (on volumetric FLAIR or post Gd T1 images). The first group was composed of 221 gliomas (168 LGGs, 53 HGGs); 130 were frontal, 21 in the insula, 58 temporal, and 12 parietal. Object naming was applied for subcortical mapping in all cases; 198 patients had immediate post operative deficits. Neuropsychological evaluation at 1 months showed complete recovery in 199 patients, a mild impairment was documented in 22 patients (12 posterior temporal tumors, 6 parietal tumors, and 4 posterior insular tumors); at 3 months evaluation, 15 patients still showed a mild impairment, mainly those whose tumors were located in the posterior temporal and parietal location. EOR was total and subtotal in 48.9% and 41.5% of cases. Fatigue was observed in 12% of patients with large volume tumors. The second group was composed of 179 gliomas (155 LGGs, 24 HGGs); 61 were frontal, 38 insular, 45 temporal and 11 parietal. Object naming was used for initial mapping and for locating main subcortical tracts (IFOF, ARC, UNC); in addition, when the initial portion of these tracts was identified, other tests were applied during subcortical mapping. 165 patients had immediate post operative deficits, only 2 patients had a mild impairment at 1 and 3 months evaluation. EOR was total and subtotal in 49.6% and 47.4% of cases. Patient fatigue was shown in 9% of patients. Object naming can be safely used during subcortical mapping for resection of tumors in frontal lobe; resection of tumors in posterior temporal, insular and parietal areas requires the use of a larger battery of tests, which did not influence the chance to reach a total or subtotal resection, nor results in a higher chance of patient fatigue.

  1. Myelin Water Fraction Is Transiently Reduced after a Single Mild Traumatic Brain Injury – A Prospective Cohort Study in Collegiate Hockey Players

    PubMed Central

    Vavasour, Irene; Shahinfard, Elham; Kolind, Shannon; van Donkelaar, Paul; Taunton, Jack; Li, David; Rauscher, Alexander

    2016-01-01

    Impact-related mild traumatic brain injuries (mTBI) are a major public health concern, and remain as one of the most poorly understood injuries in the field of neuroscience. Currently, the diagnosis and management of such injuries are based largely on patient-reported symptoms. An improved understanding of the underlying pathophysiology of mTBI is urgently needed in order to develop better diagnostic and management protocols. Specifically, dynamic post-injury changes to the myelin sheath in the human brain have not been examined, despite ‘compromised white matter integrity’ often being described as a consequence of mTBI. In this preliminary cohort study, myelin water imaging was used to prospectively evaluate changes in myelin water fraction, derived from the T2 decay signal, in two varsity hockey teams (45 players) over one season of athletic competition. 11 players sustained a concussion during competition, and were scanned at 72 hours, 2 weeks, and 2 months post-injury. Results demonstrated a reduction in myelin water fraction at 2 weeks post-injury in several brain areas relative to preseason scans, including the splenium of the corpus callosum, right posterior thalamic radiation, left superior corona radiata, left superior longitudinal fasciculus, and left posterior limb of the internal capsule. Myelin water fraction recovered to pre-season values by 2 months post-injury. These results may indicate transient myelin disruption following a single mTBI, with subsequent remyelination of affected neurons. Myelin disruption was not apparent in the athletes who did not experience a concussion, despite exposure to repetitive subconcussive trauma over a season of collegiate hockey. These findings may help to explain many of the metabolic and neurological deficits observed clinically following mTBI. PMID:26913900

  2. Structural Connectivity is Differently Altered in Dementia with Lewy Body and Alzheimer’s Disease

    PubMed Central

    Delli Pizzi, Stefano; Franciotti, Raffaella; Taylor, John-Paul; Esposito, Roberto; Tartaro, Armando; Thomas, Astrid; Onofrj, Marco; Bonanni, Laura

    2015-01-01

    The structural connectivity within cortical areas and between cortical and subcortical structures was investigated in dementia with Lewy bodies (DLB) and Alzheimer’s disease (AD). We hypothesized that white matter (WM) tracts, which are linked to visual, attentional, and mnemonic functions, would be differentially and selectively affected in DLB as compared to AD and age-matched control subjects. Structural tensor imaging and diffusion tensor imaging (DTI) were performed on 14 DLB patients, 14 AD patients, and 15 controls. DTI metrics related to WM damage were assessed within tracts reconstructed by FreeSurfer’s TRActs Constrained by UnderLying Anatomy pipeline. Correlation analysis between WM and gray matter (GM) metrics was performed to assess whether the structural connectivity alteration in AD and DLB could be secondary to GM neuronal loss or a consequence of direct WM injury. Anterior thalamic radiation (ATR) and cingulum-cingulate gyrus were altered in DLB, whereas cingulum-angular bundle (CAB) was disrupted in AD. In DLB patients, secondary axonal degeneration within ATR was found in relation to microstructural damage within medio-dorsal thalamus, whereas axonal degeneration within CAB was related to precuneus thinning. WM alteration within the uncinate fasciculus was present in both groups of patients and was related to frontal and to temporal thinning in DLB and AD, respectively. We found structural connectivity alterations within fronto-thalamic and fronto-parietal (precuneus) network in DLB whereas, in contrast, disruption of structural connectivity of mnemonic pathways was present in AD. Furthermore, the high correlation between GM and WM metrics suggests that the structural connectivity alteration in DLB could be linked to GM neuronal loss rather than by direct WM injury. Thus, this finding supports the key role of cortical and subcortical atrophy in DLB. PMID:26578952

  3. Cortical Activity Predicts Which Older Adults Recognize Speech in Noise and When

    PubMed Central

    Kuchinsky, Stefanie E.; Ahlstrom, Jayne B.; Dubno, Judy R.

    2015-01-01

    Speech recognition in noise can be challenging for older adults and elicits elevated activity throughout a cingulo-opercular network that is hypothesized to monitor and modify behaviors to optimize performance. A word recognition in noise experiment was used to test the hypothesis that cingulo-opercular engagement provides performance benefit for older adults. Healthy older adults (N = 31; 50–81 years of age; mean pure tone thresholds <32 dB HL from 0.25 to 8 kHz, best ear; species: human) performed word recognition in multitalker babble at 2 signal-to-noise ratios (SNR = +3 or +10 dB) during a sparse sampling fMRI experiment. Elevated cingulo-opercular activity was associated with an increased likelihood of correct recognition on the following trial independently of SNR and performance on the preceding trial. The cingulo-opercular effect increased for participants with the best overall performance. These effects were lower for older adults compared with a younger, normal-hearing adult sample (N = 18). Visual cortex activity also predicted trial-level recognition for the older adults, which resulted from discrete decreases in activity before errors and occurred for the oldest adults with the poorest recognition. Participants demonstrating larger visual cortex effects also had reduced fractional anisotropy in an anterior portion of the left inferior frontal-occipital fasciculus, which projects between frontal and occipital regions where activity predicted word recognition. Together, the results indicate that older adults experience performance benefit from elevated cingulo-opercular activity, but not to the same extent as younger adults, and that declines in attentional control can limit word recognition. PMID:25740521

  4. Developmental Differences in Diffusion-Tensor Imaging Parameters in Borderline Personality Disorder

    PubMed Central

    New, Antonia S.; Carpenter, David M.; Perez-Rodriguez, M. Mercedes; Ripoll, Luis H.; Avedon, Jennifer; Patil, Uday; Hazlett, Erin A.; Goodman, Marianne

    2013-01-01

    Background Borderline personality disorder (BPD) often presents during adolescence. Early detection and intervention decreases its subsequent severity. However, little is known about early predictors and biological underpinnings of BPD. The observed abnormal functional connectivity among brain regions in BPD led to studies of white matter, as the neural substrate of connectivity. However, diffusion tensor imaging (DTI) studies in adult BPD have been inconclusive, and, as yet, there are no published DTI studies in borderline adolescents. Methods We conducted DTI tractography in 38 BPD patients (14-adolescents,24-adults) and 32 healthy controls (13-adolescents,19-adults). Results We found bilateral tract-specific decreased fractional anisotropy (FA) in inferior longitudinal fasciculus (ILF) in BPD adolescents compared to adolescent controls. ILF FA was significantly higher in adolescent controls compared to BPD adolescents, BPD adults and adult controls (WilksF(3,57)=3.55, p<0.02). Follow-up voxelwise TBSS analysis demonstrated lower FA in BPD adolescents compared to adolescent controls also in uncinate and occipitofrontal fasciculi. Discussion FA generally develops along an inverted U-shape curve, increasing through adolescence, and slowly decreasing in adulthood. Our findings suggest that, in adolescent BPD, this normal developmental “peak” in FA, which is seen in healthy controls, is not achieved. This suggests a possible neural substrate for the previously reported OFC-amygdala disconnect in adults with BPD. It raises the possibility that a white matter tract abnormality in BPD present in adolescence may not be appreciable in adulthood, but a functional abnormality in the coordination among brain regions persists. Our finding represents a possible biological marker to identify those at risk for developing BPD. PMID:23628384

  5. Selective asymmetry in a conserved forebrain to midbrain projection.

    PubMed

    Kuan, Yung-Shu; Gamse, Joshua T; Schreiber, Alexander M; Halpern, Marnie E

    2007-09-15

    How the left and right sides of the brain acquire anatomical and functional specializations is not well understood. The zebrafish has proven to be a useful model to explore the genetic basis of neuroanatomical asymmetry in the developing forebrain. The dorsal diencephalon or epithalamus consists of the asymmetric pineal complex and adjacent paired nuclei, the left and right medial habenulae, which in zebrafish larvae, exhibit differences in their size, neuropil density and patterns of gene expression. In all vertebrates, axons from the medial habenular nuclei project within a prominent fiber bundle, the fasciculus retroflexus, to a shared midbrain target, the interpeduncular nucleus of the ventral tegmentum. However, in zebrafish, projections from the left habenula innervate the dorsal and ventral regions of the target nucleus, whereas right habenular efferents project only to the ventral region. A similar dorsoventral difference in habenular connectivity is found in another teleost species, the highly derived southern flounder, Paralichthys lethostima. In this flatfish, directional asymmetry of the habenular projection appears to be independent of the left-right morphology and orientation that an individual adopts post-metamorphosis. Comparative anterograde labeling of the brains of salamanders, frogs and mice reveals that axons emanating from the left and right medial habenulae do not project to different domains, but rather, they traverse the target nucleus in a complementary mirror image pattern. Thus, although the habenulo-interpeduncular conduction system is highly conserved in the vertebrate brain, the stereotypic dorsoventral topography of left-right connections appears to be a feature that is specific to teleosts. PMID:17592620

  6. Electroconvulsive therapy mediates neuroplasticity of white matter microstructure in major depression

    PubMed Central

    Lyden, H; Espinoza, R T; Pirnia, T; Clark, K; Joshi, S H; Leaver, A M; Woods, R P; Narr, K L

    2014-01-01

    Whether plasticity of white matter (WM) microstructure relates to therapeutic response in major depressive disorder (MDD) remains uncertain. We examined diffusion tensor imaging (DTI) correlates of WM structural connectivity in patients receiving electroconvulsive therapy (ECT), a rapidly acting treatment for severe MDD. Tract-Based Spatial Statistics (TBSS) applied to DTI data (61 directions, 2.5 mm3 voxel size) targeted voxel-level changes in fractional anisotropy (FA), and radial (RD), axial (AD) and mean diffusivity (MD) in major WM pathways in MDD patients (n=20, mean age: 41.15 years, 10.32 s.d.) scanned before ECT, after their second ECT and at transition to maintenance therapy. Comparisons made at baseline with demographically similar controls (n=28, mean age: 39.42 years, 12.20 s.d.) established effects of diagnosis. Controls were imaged twice to estimate scanning-related variance. Patients showed significant increases of FA in dorsal fronto-limbic circuits encompassing the anterior cingulum, forceps minor and left superior longitudinal fasciculus between baseline and transition to maintenance therapy (P<0.05, corrected). Decreases in RD and MD were observed in overlapping regions and the anterior thalamic radiation (P<0.05, corrected). Changes in DTI metrics associated with therapeutic response in tracts showing significant ECT effects differed between patients and controls. All measures remained stable across time in controls. Altered WM microstructure in pathways connecting frontal and limbic areas occur in MDD, are modulated by ECT and relate to therapeutic response. Increased FA together with decreased MD and RD, which trend towards normative values with treatment, suggest increased fiber integrity in dorsal fronto-limbic pathways involved in mood regulation. PMID:24713861

  7. Validating Serum S100B and Neuron-Specific Enolase as Biomarkers for the Human Brain – A Combined Serum, Gene Expression and MRI Study

    PubMed Central

    Streitbürger, Daniel-Paolo; Arelin, Katrin; Kratzsch, Jürgen; Thiery, Joachim; Steiner, Johann; Villringer, Arno

    2012-01-01

    Introduction Former studies have investigated the potential of serum biomarkers for diseases affecting the human brain. In particular the glial protein S100B, a neuro- and gliotrophin inducing plasticity, seems to be involved in the pathogenesis and treatment of psychiatric diseases such as major depression and schizophrenia. Neuron-specific enolase (NSE) is a specific serum marker for neuronal damage. However, the specificity of these biomarkers for cell type and brain region has not been investigated in vivo until now. Methods We acquired two magnetic resonance imaging parameters sensitive to changes in gray and white matter (T1-weighted/diffusion tensor imaging) and obtained serum S100B and NSE levels of 41 healthy subjects. Additionally, we analyzed whole brain gene expressions of S100B in another male cohort of three subjects using the Allen Brain Atlas. Furthermore, a female post mortal brain was investigated using double immunofluorescence labelling with oligodendrocyte markers. Results We show that S100B is specifically related to white matter structures, namely the corpus callosum, anterior forceps and superior longitudinal fasciculus in female subjects. This effect was observed in fractional anisotropy and radial diffusivity – the latest an indicator of myelin changes. Histological data confirmed a co-localization of S100B with oligodendrocyte markers in the human corpus callosum. S100B was most abundantly expressed in the corpus callosum according to the whole genome Allen Human Brain Atlas. In addition, NSE was related to gray matter structures, namely the amygdala. This effect was detected across sexes. Conclusion Our data demonstrates a very high S100B expression in white matter tracts, in particular in human corpus callosum. Our study is the first in vivo study validating the specificity of the glial marker S100B for the human brain, and supporting the assumption that radial diffusivity represents a myelin marker. Our results open a new perspective for future studies investigating major neuropsychiatric disorders. PMID:22916238

  8. Associations Between White Matter Microstructure and Infants’ Working Memory

    PubMed Central

    Short, Sarah J.; Elison, Jed T.; Goldman, Barbara Davis; Styner, Martin; Gu, Hongbin; Connelly, Mark; Maltbie, Eric; Woolson, Sandra; Lin, Weili; Gerig, Guido; Reznick, J. Steven; Gilmore, John H.

    2013-01-01

    Working memory emerges in infancy and plays a privileged role in subsequent adaptive cognitive development. The neural networks important for the development of working memory during infancy remain unknown. We used diffusion tensor imaging (DTI) and deterministic fiber tracking to characterize the microstructure of white matter fiber bundles hypothesized to support working memory in 12-month-old infants (n=73). Here we show robust associations between infants’ visuospatial working memory performance and microstructural characteristics of widespread white matter. Significant associations were found for white matter tracts that connect brain regions known to support working memory in older children and adults (genu, anterior and superior thalamic radiations, anterior cingulum, arcuate fasciculus, and the temporal-parietal segment). Better working memory scores were associated with higher FA and lower RD values in these selected white matter tracts. These tract-specific brain-behavior relationships accounted for a significant amount of individual variation above and beyond infants’ gestational age and developmental level, as measured with the Mullen Scales of Early Learning. Working memory was not associated with global measures of brain volume, as expected, and few associations were found between working memory and control white matter tracts. To our knowledge, this study is among the first demonstrations of brain-behavior associations in infants using quantitative tractography. The ability to characterize subtle individual differences in infant brain development associated with complex cognitive functions holds promise for improving our understanding of normative development, biomarkers of risk, experience-dependent learning and neuro-cognitive periods of developmental plasticity. PMID:22989623

  9. Paraventricular organ of the lungfish Protopterus dolloi: morphology and projections of CSF-contacting neurons.

    PubMed

    von Bartheld, C S; Meyer, D L

    1990-07-15

    The morphology and projections of neurons in the paraventricular organ (PVO) were studied by means of silver impregnation after intraocular application of cobaltous lysine in the lungfish Protopterus dolloi. Cobalt-labeled neurons were found exclusively in the PVO in the dorsal and infundibular hypothalamus. These bipolar neurons possess one CSF-contacting process that protrudes into the ventricular lumen with a club-shape ending and a thick, ramifying process directed into the hypothalamic neuropil; the ependymofugal processes form intra- and extrahypothalamic projections. Impregnated fibers from paraventricular neurons cross in infundibular and hypothalamic commissures, the commissure of the posterior tuberculum, the postoptic, the habenular, and the anterior commissures. Projections to the infundibulum and the median eminence are relatively sparse; no fibers are labeled in the pituitary gland. Ascending projections to the forebrain are extensive. Major targets include the dorsal hypothalamus, the periventricular preoptic nuclei, the habenula, the subhabenular region, the anterodorsal thalamus, and the medial telencephalic hemisphere (septum). Most ascending fibers follow the medial forebrain bundle; others course in the fasciculus retroflexus and terminate in rostral parts of the ipsilateral habenula. Descending fibers run caudally along the ventral floor of the brainstem. They terminate in the neuropil of the mesencephalic tegmentum, ventral tectum, isthmic region, ventral portions of the reticular formation throughout the rhombencephalon, and extend into the spinal cord. Intraocular application of cobaltous lysine results in selective impregnation of neurons in the PVO and their ascending and descending projections, presumably via uptake of tracer from vascular circulation. These projections do not represent retinofugal or retinopetal projections. We provide conclusive evidence for the existence of a PVO in Protopterus. On the basis of PVO location and acetylcholinesterase histochemistry, we propose subdivisions of the infundibular hypothalamus corresponding to those in amphibians. Ascending PVO projections appear to be particularly well developed in lungfish compared with other species and may be related to specialized endocrine mechanisms in this group of vertebrates. PMID:2398140

  10. Foix-Chavany-Marie syndrome caused by a disconnection between the right pars opercularis of the inferior frontal gyrus and the supplementary motor area.

    PubMed

    Martino, Juan; de Lucas, Enrique Marco; Ibáñez-Plágaro, Francisco Javier; Valle-Folgueral, José Manuel; Vázquez-Barquero, Alfonso

    2012-11-01

    Foix-Chavany-Marie syndrome (FCMS) is a rare type of suprabulbar palsy characterized by an automatic-voluntary dissociation of the orofacial musculature. Here, the authors report an original case of FCMS that occurred intraoperatively while resecting the pars opercularis of the inferior frontal gyrus. This 25-year-old right-handed man with an incidentally diagnosed right frontotemporoinsular tumor underwent surgery using an asleep-awake-asleep technique with direct cortical and subcortical electrical stimulation and a transopercular approach to the insula. While resecting the anterior part of the pars opercularis the patient suffered sudden anarthria and bilateral facial weakness. He was unable to speak or show his teeth on command, but he was able to voluntarily move his upper and lower limbs. This syndrome lasted for 8 days. Postoperative diffusion tensor imaging tractography revealed that connections of the pars opercularis of the right inferior frontal gyrus with the frontal aslant tract (FAT) and arcuate fasciculus (AF) were damaged. This case supplies evidence for localizing the structural substrate of FCMS. It was possible, for the first time in the literature, to accurately correlate the occurrence of FCMS to the resection of connections between the FAT and AF, and the right pars opercularis of the inferior frontal gyrus. The FAT has been recently described, but it may be an important connection to mediate supplementary motor area control of orofacial movement. The present case also contributes to our knowledge of complication avoidance in operculoinsular surgery. A transopercular approach to insuloopercular gliomas can generate FCMS, especially in cases of previous contralateral lesions. The prognosis is favorable, but the patient should be informed of this particular hazard, and the surgeon should anticipate the surgical strategy in case the syndrome occurs intraoperatively in an awake patient. PMID:22957529

  11. Diffuse Interstitial Brain Edema in Patients With End-Stage Renal Disease Undergoing Hemodialysis: A Tract-Based Spatial Statistics Study

    PubMed Central

    Kong, Xiang; Wen, Ji-qiu; Qi, Rong-feng; Luo, Song; Zhong, Jian-hui; Chen, Hui-juan; Ji, Gong-jun; Lu, Guang Ming; Zhang, Long Jiang

    2014-01-01

    Abstract To investigate white matter (WM) alterations and their correlation with cognition function in end-stage renal disease (ESRD) patients undergoing hemodialysis (HD) using diffusion tensor imaging (DTI) with tract-based spatial statistics (TBSS) approach. This prospective HIPAA-complaint study was approved by our institutional review board. Eighty HD ESRD patients and 80 sex- and age-matched healthy controls were included. Neuropsychological (NP) tests and laboratory tests, including serum creatinine and urea, were performed. DTI data were processed to obtain fractional anisotropy (FA) and mean diffusivity (MD) maps with TBSS. FA and MD difference between the 2 groups were compared. We also explored the associations of FA values in WM regions of lower FA with ages, NP tests, disease, and dialysis durations, serum creatinine and urea levels of ESRD patients. Compared with controls, HD ESRD patients had lower FA value in the corpus callosum, bilateral corona radiate, posterior thalamic radiation, left superior longitudinal fasciculus, and right cingulum (P??0.05). Diffuse interstitial brain edema and moderate WM integrity disruption occurring in HD ESRD patients, which correlated with cognitive dysfunction, and serum urea levels might be a risk factor for these WM changes. PMID:25526483

  12. Vestibular-evoked myogenic potentials in central vestibular disorders.

    PubMed

    Oh, Sun-Young; Kim, Hyo-Jeong; Kim, Ji-Soo

    2016-02-01

    Vestibular-evoked myogenic potentials (VEMPs) are short latency manifestations of vestibulo-ocular and vestibulocollic reflexes that originate from the utricle and saccule. Although cervical and ocular VEMPs have mostly been applied to peripheral vestibular disorders, the characteristics and the diagnostic values of VEMPs have been expanded to assess the function of the central otolithic pathways. In the central nervous system, the cervical VEMPs (cVEMPs) are mediated by the vestibular nuclei and uncrossed medial vestibulospinal tract descending in the lower brainstem and spinal cord. In contrast, the ocular VEMPs (oVEMPs) reflect the function of the vestibular nuclei and the crossed vestibulo-ocular reflex (VOR) pathways, mostly contained in the medial longitudinal fasciculus (MLF). Therefore, lesions involving the vestibular nuclei can present abnormalities of both cVEMPs and oVEMPs. The medullary lesions involving the descending MLF or the spinal accessory nucleus impair cVEMPs. In contrast, the lesions involving the MLF, the crossed ventral tegmental tract, oculomotor nuclei and the interstitial nucleus of Cajal can impair oVEMPs. Patients with unilateral cerebellar infarctions may show abnormal VEMPs especially when they have the ocular tilt reaction. Delayed responses of VEMPs are characteristic of multiple sclerosis (MS). Reduced VEMP responses can be observed in patients with vestibular migraine. VEMPs are useful in evaluating central as well as peripheral otolithic function that are not readily defined by conventional vestibular function tests, and can aid in detecting and localizing central lesions, especially silent brainstem lesions such as tiny infarctions or MS plaques. PMID:26239221

  13. A distributed network critical for selecting among tool-directed actions.

    PubMed

    Watson, Christine E; Buxbaum, Laurel J

    2015-04-01

    Tools pose a challenge to the need to select actions appropriate for task goals and environmental constraints. For many tools (e.g., calculator), actions for "using" and "grasping-to-move" conflict with each other and may compete during selection. To date, little is known about the mechanisms that enable selection between possible tool actions or their neural substrates. The study of patients with chronic left hemisphere stroke, many of whom are deficient in tool-use action (apraxic), provides an opportunity to elucidate these issues. Here, 31 such patients pantomimed or recognized tool use actions for "conflict" and "non-conflict" tools. Voxel-based lesion-symptom mapping (VLSM), lesion subtraction, and tractographic overlap analyses were used to determine brain regions necessary for selecting among tool-directed actions. Lesions to posterior middle temporal gyrus (pMTG) and anterior intraparietal sulcus (aIPS) tended to impair production of use actions similarly for both conflict and non-conflict tools. By contrast, lesions to the supramarginal gyrus (SMG), inferior frontal gyrus (IFG)/anterior insula, and superior longitudinal fasciculus (SLF) specifically impaired production of use actions for conflict tools. Patients' errors on conflict tools suggested inappropriate selection of grasping actions and difficulty selecting single actions. Use/grasp conflict had no effect on action recognition. We suggest that the SMG/SLF/IFG pathway implements biased competition between possible tool actions, while aIPS and pMTG compute the structure-based and skilled use actions, respectively, that constitute input to this competitive process. This is the first study to demonstrate a reliable link between a characteristic of single tools (i.e., their association with different use and grasp actions) and action selection difficulties. Additionally, the data allow us to posit an SMG-involved subtype of apraxia characterized by an inability to resolve action competition. PMID:25681649

  14. Longitudinal Diffusion Tensor Imaging in Frontotemporal Dementia

    PubMed Central

    Mahoney, Colin J; Simpson, Ivor J A; Nicholas, Jennifer M; Fletcher, Phillip D; Downey, Laura E; Golden, Hannah L; Clark, Camilla N; Schmitz, Nicole; Rohrer, Jonathan D; Schott, Jonathan M; Zhang, Hui; Ourselin, Sebastian; Warren, Jason D; Fox, Nick C

    2015-01-01

    Objective Novel biomarkers for monitoring progression in neurodegenerative conditions are needed. Measurement of microstructural changes in white matter (WM) using diffusion tensor imaging (DTI) may be a useful outcome measure. Here we report trajectories of WM change using serial DTI in a cohort with behavioral variant frontotemporal dementia (bvFTD). Methods Twenty-three patients with bvFTD (12 having genetic mutations), and 18 age-matched control participants were assessed using DTI and neuropsychological batteries at baseline and ∼1.3 years later. Baseline and follow-up DTI scans were registered using a groupwise approach. Annualized rates of change for DTI metrics, neuropsychological measures, and whole brain volume were calculated. DTI metric performances were compared, and sample sizes for potential clinical trials were calculated. Results In the bvFTD group as a whole, rates of change in fractional anisotropy (FA) and mean diffusivity (MD) within the right paracallosal cingulum were greatest (FA: −6.8%/yr, p < 0.001; MD: 2.9%/yr, p = 0.01). MAPT carriers had the greatest change within left uncinate fasciculus (FA: −7.9%/yr, p < 0.001; MD: 10.9%/yr, p < 0.001); sporadic bvFTD and C9ORF72 carriers had the greatest change within right paracallosal cingulum (sporadic bvFTD, FA: −6.7%/yr, p < 0.001; MD: 3.8%/yr, p = 0.001; C9ORF72, FA: −6.8%/yr, p = 0.004). Sample size estimates using FA change were substantially lower than neuropsychological or whole brain measures of change. Interpretation Serial DTI scans may be useful for measuring disease progression in bvFTD, with particular trajectories of WM damage emerging. Sample size calculations suggest that longitudinal DTI may be a useful biomarker in future clinical trials. PMID:25363208

  15. Declines in inflammation predict greater white matter microstructure in older adults

    PubMed Central

    Bettcher, Brianne Magouirk; Yaffe, Kristine; Boudreau, Robert; Neuhaus, John; Aizenstein, Howard; Ding, Jingzhong; Kritchevsky, Stephen B.; Launer, Lenore J.; Liu, Yongmei; Satterfield, Suzanne; Rosano, Caterina

    2015-01-01

    Objective Protracted, systemic inflammation has been associated with adverse effects on cognition and brain structure, and may accelerate neurodegenerative disease processes; however, it is less clear whether changes in inflammation are associated with brain structure. Methods We studied 276 black and white older adults (mean age=83 years at time of imaging) enrolled in a prospective study of aging. Inflammation (measured with CRP) was assessed repeatedly over 6 years (i.e. Year 2, 4, 6, & 8). Brain MRIs were obtained at years 10–11 with DTI; regions of interest included late-myelinating areas vulnerable to aging, including frontal-parietal [superior longitudinal fasciculus (SLF)-dorsal] and temporal (SLF-temporal; uncinate) white matter tracts. Results Mean CRP values significantly declined (t=?5.54, p<.0001) over 6 years, and subject-specific slopes (BLUPs) all showed a decline (mean=?.57, SD=.53) for our participant sample. More than 50% of study participants were still in the moderate to high cardiovascular risk range based on CRP values at Year 8. After controlling for demographics, vascular risk factors and MRI white matter hyperintensities, larger decreases in CRP values over time were significantly associated with higher fractional anisotropy in the SLF-dorsal [Beta=?0.0052, standard error (SE)=0.003; 95% confidence interval (CI)= ?0.0103 to ?0.0025, p=.04], SLF-temporal (Beta=?0.0109, SE=0.004; 95%CI=?0.0189 to ?0.0029, p=.008), and uncinate (Beta=?0.0067, SE=0.003; 95%CI=?0.0132 to ?0.0001, p=.05) fasciculi. Conclusions Results suggest that in a prospective cohort of older individuals, faster declines in inflammation over time are related to indicators of white matter health, even after accounting for vascular risk factors. PMID:25554492

  16. Expression of mu opioid receptor in dorsal diencephalic conduction system: new insights for the medial habenula

    PubMed Central

    Gardon, O.; Faget, L.; Chu Sin Chung, P.; Matifas, A.; Massotte, D; Kieffer, B.L.

    2014-01-01

    The habenular complex, encompassing medial (MHb) and lateral (LHb) divisions, is a highly conserved epithalamic structure involved in the dorsal diencephalic conduction system (DDC). These brain nuclei regulate information flow between the limbic forebrain and the mid- and hindbrain, integrating cognitive with emotional and sensory processes. The MHb is also one of the strongest expression sites for mu opioid receptors (MORs), which mediate analgesic and rewarding properties of opiates. At present however, anatomical distribution and function of these receptors have been poorly studied in MHb pathways. Here we took advantage of a newly generated MOR-mcherry knock-in mouse line to characterize MOR expression sites in the DDC. MOR-mcherry fluorescent signal is weak in the lateral habenula, but strong expression is visible in the medial habenula, fasciculus retroflexus and interpeduncular nucleus (IPN), indicating that MOR is mainly present in the MHb-IPN pathway. MOR-mcherry cell bodies are detected both in basolateral and apical parts of MHb, where the receptor co-localizes with cholinergic and Substance P (SP) neurons, respectively, representing two main MHb neuronal populations. MOR-mcherry is expressed in most MHb-SP neurons, and is present in only a subpopulation of MHb-cholinergic neurons. Intense diffuse fluorescence detected in lateral and rostral parts of the IPN further suggests that MOR-mcherry is transported to terminals of these SP and cholinergic neurons. Finally, MOR-mcherry is present in septal regions projecting to the MHb, and in neurons of the central and intermediate IPN. Together, this study describes MOR expression in several compartments of the MHb-IPN circuitry. The remarkably high MOR density in the MHb-IPN pathway suggests that these receptors are in a unique position to mediate analgesic, autonomic and reward responses. PMID:25086313

  17. The Evolution of Syntax: An Exaptationist Perspective

    PubMed Central

    Fitch, W. Tecumseh

    2011-01-01

    The evolution of language required elaboration of a number of independent mechanisms in the hominin lineage, including systems involved in signaling, semantics, and syntax. Two perspectives on the evolution of syntax can be contrasted. The “continuist” perspective seeks the evolutionary roots of complex human syntax in simpler combinatory systems used in animal communication systems, such as iteration and sequencing. The “exaptationist” perspective posits evolutionary change of function, so that systems today used for linguistic communication might previously have served quite different functions in earlier hominids. I argue that abundant biological evidence supports an exaptationist perspective, in general, and that it must be taken seriously when considering language evolution. When applied to syntax, this suggests that core computational components used today in language could have originally served non-linguistic functions such as motor control, non-verbal thought, or spatial reasoning. I outline three specific exaptationist hypotheses for spoken language. These three hypotheses each posit a change of functionality in a precursor circuit, and its transformation into a neural circuit or region specifically involved in language today. Hypothesis 1 suggests that the precursor mechanism for intentional vocal control, specifically direct cortical control over the larynx, was manual motor control subserved by the cortico-spinal tract. The second is that the arcuate fasciculus, which today connects syntactic and lexical regions, had its origin in intracortical connections subserving vocal imitation. The third is that the specialized components of Broca’s area, specifically BA 45, had their origins in non-linguistic motor control, and specifically hierarchical planning of action. I conclude by illustrating the importance of both homology (studied via primates) and convergence (typically analyzed in birds) for testing such evolutionary hypotheses. PMID:22207847

  18. Discriminating Schizophrenia and Bipolar Disorder by Fusing FMRI and DTI in A Multimodal CCA+ Joint ICA Model

    PubMed Central

    Sui, Jing; Pearlson, Godfrey; Adali, Tülay; Kiehl, Kent A.; Caprihan, Arvind; Liu, Jingyu; Yamamoto, Jeremy; Calhoun, Vince D.

    2011-01-01

    Diverse structural and functional brain alterations have been identified in both schizophrenia and bipolar disorder, but with variable replicability, significant overlap and often in limited number of subjects. In this paper, we aimed to clarify differences between bipolar disorder and schizophrenia by combining fMRI (collected during an auditory oddball task) and diffusion tensor imaging (DTI) data. We proposed a fusion method, “multimodal CCA+ joint ICA’, which increases flexibility in statistical assumptions beyond existing approaches and can achieve higher estimation accuracy. The data collected from 164 participants (62 healthy controls, 54 schizophrenia and 48 bipolar) were extracted into “features” (contrast maps for fMRI and fractional anisotropy (FA) for DTI) and analyzed in multiple facets to investigate the group differences for each pair-wised groups and each modality. Specifically, both patient groups shared significant dysfunction in dorsolateral prefrontal cortex and thalamus, as well as reduced white matter (WM) integrity in anterior thalamic radiation and uncinate fasciculus. Schizophrenia and bipolar subjects were separated by functional differences in medial frontal and visual cortex, as well as WM tracts associated with occipital and frontal lobes. Both patients and controls showed similar spatial distributions in motor and parietal regions, but exhibited significant variations in temporal lobe. Furthermore, there were different group trends for age effects on loading parameters in motor cortex and multiple WM regions, suggesting brain dysfunction and WM disruptions occurred in identified regions for both disorders. Most importantly, we can visualize an underlying function-structure network by evaluating the joint components with strong links between DTI and fMRI. Our findings suggest that although the two patient groups showed several distinct brain patterns from each other and healthy controls, they also shared common abnormalities in prefrontal thalamic WM integrity and in frontal brain mechanisms. PMID:21640835

  19. Coexpression of high-voltage-activated ion channels Kv3.4 and Cav1.2 in pioneer axons during pathfinding in the developing rat forebrain.

    PubMed

    Huang, Chia-Yi; Chu, Dachen; Hwang, Wei-Chao; Tsaur, Meei-Ling

    2012-11-01

    Precise axon pathfinding is crucial for establishment of the initial neuronal network during development. Pioneer axons navigate without the help of preexisting axons and pave the way for follower axons that project later. Voltage-gated ion channels make up the intrinsic electrical activity of pioneer axons and regulate axon pathfinding. To elucidate which channel molecules are present in pioneer axons, immunohistochemical analysis was performed to examine 14 voltage-gated ion channels (Kv1.1-Kv1.3, Kv3.1-Kv3.4, Kv4.3, Cav1.2, Cav1.3, Cav2.2, Nav1.2, Nav1.6, and Nav1.9) in nine axonal tracts in the developing rat forebrain, including the optic nerve, corpus callosum, corticofugal fibers, thalamocortical axons, lateral olfactory tract, hippocamposeptal projection, anterior commissure, hippocampal commissure, and medial longitudinal fasciculus. We found A-type K? channel Kv3.4 in both pioneer axons and early follower axons and L-type Ca²? channel Cav1.2 in pioneer axons and early and late follower axons. Spatially, Kv3.4 and Cav1.2 were colocalized with markers of pioneer neurons and pioneer axons, such as deleted in colorectal cancer (DCC), in most fiber tracts examined. Temporally, Kv3.4 and Cav1.2 were expressed abundantly in most fiber tracts during axon pathfinding but were downregulated beginning in synaptogenesis. By contrast, delayed rectifier Kv channels (e.g., Kv1.1) and Nav channels (e.g., Nav1.2) were absent from these fiber tracts (except for the corpus callosum) during pathfinding of pioneer axons. These data suggest that Kv3.4 and Cav1.2, two high-voltage-activated ion channels, may act together to control Ca²? -dependent electrical activity of pioneer axons and play important roles during axon pathfinding. PMID:22473424

  20. Altered interhemispheric and temporal lobe white matter microstructural organization in severe chronic schizophrenia.

    PubMed

    Holleran, Laurena; Ahmed, Mohamed; Anderson-Schmidt, Heike; McFarland, John; Emsell, Louise; Leemans, Alexander; Scanlon, Cathy; Dockery, Peter; McCarthy, Peter; Barker, Gareth J; McDonald, Colm; Cannon, Dara M

    2014-03-01

    Diffusion MRI investigations in schizophrenia provide evidence of abnormal white matter (WM) microstructural organization as indicated by reduced fractional anisotropy (FA) primarily in interhemispheric, left frontal and temporal WM. Using tract-based spatial statistics (TBSS), we examined diffusion parameters in a sample of patients with severe chronic schizophrenia. Diffusion MRI data were acquired on 19 patients with chronic severe schizophrenia and 19 age- and gender-matched healthy controls using a 64 gradient direction sequence, (b=1300 s/mm(2)) collected on a Siemens 1.5T MRI scanner. Diagnosis of schizophrenia was determined by Diagnostic and Statistical Manual for Mental Disorders 4th Edition (DSM-IV) Structured Clinical Interview for DSM disorder (SCID). Patients were treatment resistance, having failed to respond to at least two antipsychotic medications, and had prolonged periods of moderate to severe positive or negative symptoms. Analysis of diffusion parameters was carried out using TBSS. Individuals with chronic severe schizophrenia had significantly reduced FA with corresponding increased radial diffusivity in the genu, body, and splenium of the corpus callosum, the right posterior limb of the internal capsule, right external capsule, and the right temporal inferior longitudinal fasciculus. There were no voxels of significantly increased FA in patients compared with controls. A decrease in splenium FA was shown to be related to a longer illness duration. We detected widespread abnormal diffusivity properties in the callosal and temporal lobe WM regions in individuals with severe chronic schizophrenia who have not previously been exposed to clozapine. These deficits can be driven by a number of factors that are indistinguishable using in vivo diffusion-weighted imaging, but may be related to reduced axonal number or packing density, abnormal glial cell arrangement or function, and reduced myelin. PMID:24150571

  1. Effects of chronic mild traumatic brain injury on white matter integrity in Iraq and Afghanistan war veterans.

    PubMed

    Morey, Rajendra A; Haswell, Courtney C; Selgrade, Elizabeth S; Massoglia, Dino; Liu, Chunlei; Weiner, Jonathan; Marx, Christine E; Cernak, Ibolja; McCarthy, Gregory

    2013-11-01

    Mild traumatic brain injury (TBI) is a common source of morbidity from the wars in Iraq and Afghanistan. With no overt lesions on structural MRI, diagnosis of chronic mild TBI in military veterans relies on obtaining an accurate history and assessment of behavioral symptoms that are also associated with frequent comorbid disorders, particularly posttraumatic stress disorder (PTSD) and depression. Military veterans from Iraq and Afghanistan with mild TBI (n = 30) with comorbid PTSD and depression and non-TBI participants from primary (n = 42) and confirmatory (n = 28) control groups were assessed with high angular resolution diffusion imaging (HARDI). White matter-specific registration followed by whole-brain voxelwise analysis of crossing fibers provided separate partial volume fractions reflecting the integrity of primary fibers and secondary (crossing) fibers. Loss of white matter integrity in primary fibers (P < 0.05; corrected) was associated with chronic mild TBI in a widely distributed pattern of major fiber bundles and smaller peripheral tracts including the corpus callosum (genu, body, and splenium), forceps minor, forceps major, superior and posterior corona radiata, internal capsule, superior longitudinal fasciculus, and others. Distributed loss of white matter integrity correlated with duration of loss of consciousness and most notably with "feeling dazed or confused," but not diagnosis of PTSD or depressive symptoms. This widespread spatial extent of white matter damage has typically been reported in moderate to severe TBI. The diffuse loss of white matter integrity appears consistent with systemic mechanisms of damage shared by blast- and impact-related mild TBI that involves a cascade of inflammatory and neurochemical events. PMID:22706988

  2. Alterations in Cerebral White Matter and Neuropsychology in Patients with Cirrhosis and Falls

    PubMed Central

    Gómez-Ansón, Beatriz; Román, Eva; Fernández de Bobadilla, Ramón; Pires-Encuentra, Patricia; Díaz-Manera, Jordi; Núñez, Fidel; Martinez-Horta, Saül; Vives-Gilabert, Yolanda; Pagonabarraga, Javier; Kulisevsky, Jaume; Guarner, Carlos; Soriano, Germán

    2015-01-01

    Background & Aim Falls are frequent in patients with cirrhosis but underlying mechanisms are unknown. The aim was to determine the neuropsychological, neurological and brain alterations using magnetic resonance-diffusion tensor imaging (MR-DTI) in cirrhotic patients with falls. Patients and methods Twelve patients with cirrhosis and falls in the previous year were compared to 9 cirrhotic patients without falls. A comprehensive neuropsychological and neurological evaluation of variables that may predispose to falls included: the Mini-Mental State Examination, Psychometric Hepatic Encephalopathy Score (PHES), Parkinson’s Disease-Cognitive Rating Scale, specific tests to explore various cognitive domains, Unified Parkinson’s Disease Rating Scale to evaluate parkinsonism, scales for ataxia and muscular strength, and electroneurography. High-field MR (3T) including DTI and structural sequences was performed in all patients. Results The main neuropsychological findings were impairment in PHES (p = 0.03), Parkinson’s Disease-Cognitive Rating Scale (p = 0.04) and in executive (p<0.05) and visuospatial-visuoconstructive functions (p<0.05) in patients with falls compared to those without. There were no statistical differences between the two groups in the neurological evaluation or in the visual assessment of MRI. MR-DTI showed alterations in white matter integrity in patients with falls compared to those without falls (p<0.05), with local maxima in the superior longitudinal fasciculus and corticospinal tract. These alterations were independent of PHES as a covariate and correlated with executive dysfunction (p<0.05). Conclusions With the limitation of the small sample size, our results suggest that patients with cirrhosis and falls present alterations in brain white matter tracts related to executive dysfunction. These alterations are independent of PHES impairment. PMID:25793766

  3. Primary Position Upbeat Nystagmus during an Acute Attack of Multiple Sclerosis

    PubMed Central

    Kim, Jee-Ae; Jeong, In-Hye; Lim, Young-Min

    2014-01-01

    Background and Purpose Ocular manifestation is one of the frequent signs of an acute attack in multiple sclerosis (MS), although primary position upbeat nystagmus (PPUN) is rare. The purpose of this study is to determine the incidence of PPUN in MS and to determine the lesions that are responsible for this sign. Methods The medical records of 120 MS patients with acute brain lesions were reviewed over a consecutive period of 9 years; of these, 6 patients were found to have PPUN. Other ocular motor abnormalities were analyzed in combination with upbeat nystagmus, video-oculographic findings, and lesions detected on brain MRI. Results Lesions in the pontine tegmentum involving the medial longitudinal fasciculus (MLF) and ventral tegmental tract (VTT) were the most common, being observed in three of the six patients with PPUN. One patient exhibited caudal medullary lesions bilaterally affecting the paramedian portion of the posterior tegmentum, and two patients exhibited multiple lesions involving the pons with the cerebral peduncle or medulla. In five patients, other ocular motor dysfunctions, such as gaze-evoked nystagmus (n=3) and internuclear ophthalmoplegia (n=1), were found in combination with upbeat nystagmus. Conclusions PPUN is an infrequent, ocular manifestation noted during an acute attack of MS, and was observed in 5% of the present cases. Brainstem lesions in these cases primarily involved the pontine tegmentum and the caudal medulla. These findings support the theory that upbeat nystagmus is attributable to damage to the upward vestibulo-ocular reflex pathway related to the vestibular nucleus, VTT, and interconnecting pathways. PMID:24465261

  4. Reduced White Matter Integrity in Sibling Pairs Discordant for Bipolar Disorder

    PubMed Central

    Sprooten, Emma; Brumbaugh, Margaret S.; Knowles, Emma E.M.; McKay, D. Reese; Lewis, John; Barrett, Jennifer; Landau, Stefanie; Cyr, Lindsay; Kochunov, Peter; Winkler, Anderson M.; Pearlson, Godfrey D.; Glahn, David C.

    2014-01-01

    Objective Several lines of evidence indicate that white matter integrity is compromised in bipolar disorder, but the nature, extent, and biological causes remain elusive. To determine the extent to which white matter deficits in bipolar disorder are familial, the authors investigated white matter integrity in a large sample of bipolar patients, unaffected siblings, and healthy comparison subjects. Method The authors collected diffusion imaging data for 64 adult bipolar patients, 60 unaffected siblings (including 54 discordant sibling pairs), and 46 demographically matched comparison subjects. Fractional anisotropy was compared between the groups using voxel-wise tract-based spatial statistics and by extracting mean fractional anisotropy from 10 regions of interest. Additionally, intra-class correlation coefficients were calculated between the sibling pairs as an index of familiality. Results Widespread fractional anisotropy reductions in bipolar patients (>40,000 voxels) and more subtle reductions in their siblings, mainly restricted to the corpus callosum, posterior thalamic radiations, and left superior longitudinal fasciculus (>2,000 voxels) were observed. Similarly, region-of-interest analysis revealed significant reductions in most white matter regions in patients. In siblings, fractional anisotropy in the posterior thalamic radiation and the forceps was nominally reduced. Significant between-sibling correlations were found for mean fractional anisotropy across the tract-based spatial statistic skeleton, within significant clusters, and within nearly all regions of interest. Conclusions These findings emphasize the relevance of white matter to neuropathology and familiality of bipolar disorder and encourage further use of white matter integrity markers as endophenotypes in genetic studies. PMID:24185242

  5. Kernel regression estimation of fiber orientation mixtures in diffusion MRI.

    PubMed

    Cabeen, Ryan P; Bastin, Mark E; Laidlaw, David H

    2016-02-15

    We present and evaluate a method for kernel regression estimation of fiber orientations and associated volume fractions for diffusion MR tractography and population-based atlas construction in clinical imaging studies of brain white matter. This is a model-based image processing technique in which representative fiber models are estimated from collections of component fiber models in model-valued image data. This extends prior work in nonparametric image processing and multi-compartment processing to provide computational tools for image interpolation, smoothing, and fusion with fiber orientation mixtures. In contrast to related work on multi-compartment processing, this approach is based on directional measures of divergence and includes data-adaptive extensions for model selection and bilateral filtering. This is useful for reconstructing complex anatomical features in clinical datasets analyzed with the ball-and-sticks model, and our framework's data-adaptive extensions are potentially useful for general multi-compartment image processing. We experimentally evaluate our approach with both synthetic data from computational phantoms and in vivo clinical data from human subjects. With synthetic data experiments, we evaluate performance based on errors in fiber orientation, volume fraction, compartment count, and tractography-based connectivity. With in vivo data experiments, we first show improved scan-rescan reproducibility and reliability of quantitative fiber bundle metrics, including mean length, volume, streamline count, and mean volume fraction. We then demonstrate the creation of a multi-fiber tractography atlas from a population of 80 human subjects. In comparison to single tensor atlasing, our multi-fiber atlas shows more complete features of known fiber bundles and includes reconstructions of the lateral projections of the corpus callosum and complex fronto-parietal connections of the superior longitudinal fasciculus I, II, and III. PMID:26691524

  6. Disruption of brain white matter microstructure in women with anorexia nervosa

    PubMed Central

    Via, Esther; Zalesky, Andrew; Sánchez, Isabel; Forcano, Laura; Harrison, Ben J.; Pujol, Jesús; Fernández-Aranda, Fernando; Menchón, José Manuel; Soriano-Mas, Carles; Cardoner, Narcís; Fornito, Alex

    2014-01-01

    Background The etiology of anorexia nervosa is still unknown. Multiple and distributed brain regions have been implicated in its pathophysiology, implying a dysfunction of connected neural circuits. Despite these findings, the role of white matter in anorexia nervosa has been rarely assessed. In this study, we used diffusion tensor imaging (DTI) to characterize alterations of white matter microstructure in a clinically homogeneous sample of patients with anorexia nervosa. Methods Women with anorexia nervosa (restricting subtype) and healthy controls underwent brain DTI. We used tract-based spatial statistics to compare fractional anisotropy (FA) and mean diffusivity (MD) maps between the groups. Furthermore, axial (AD) and radial diffusivity (RD) measures were extracted from regions showing group differences in either FA or MD. Results We enrolled 19 women with anorexia nervosa and 19 healthy controls in our study. Patients with anorexia nervosa showed significant FA decreases in the parietal part of the left superior longitudinal fasciculus (SLF; pFWE < 0.05), with increased MD and RD but no differences in AD. Patients with anorexia nervosa also showed significantly increased MD in the fornix (pFWE < 0.05), accompanied by decreased FA and increased RD and AD. Limitations Limitations include our modest sample size and cross-sectional design. Conclusion Our findings support the presence of white matter pathology in patients with anorexia nervosa. Alterations in the SLF and fornix might be relevant to key symptoms of anorexia nervosa, such as body image distortion or impairments in body–energy–balance and reward processes. The differences found in both areas replicate those found in previous DTI studies and support a role for white matter pathology of specific neural circuits in individuals with anorexia nervosa. PMID:24913136

  7. Myelin Water Fraction Is Transiently Reduced after a Single Mild Traumatic Brain Injury - A Prospective Cohort Study in Collegiate Hockey Players.

    PubMed

    Wright, Alexander D; Jarrett, Michael; Vavasour, Irene; Shahinfard, Elham; Kolind, Shannon; van Donkelaar, Paul; Taunton, Jack; Li, David; Rauscher, Alexander

    2016-01-01

    Impact-related mild traumatic brain injuries (mTBI) are a major public health concern, and remain as one of the most poorly understood injuries in the field of neuroscience. Currently, the diagnosis and management of such injuries are based largely on patient-reported symptoms. An improved understanding of the underlying pathophysiology of mTBI is urgently needed in order to develop better diagnostic and management protocols. Specifically, dynamic post-injury changes to the myelin sheath in the human brain have not been examined, despite 'compromised white matter integrity' often being described as a consequence of mTBI. In this preliminary cohort study, myelin water imaging was used to prospectively evaluate changes in myelin water fraction, derived from the T2 decay signal, in two varsity hockey teams (45 players) over one season of athletic competition. 11 players sustained a concussion during competition, and were scanned at 72 hours, 2 weeks, and 2 months post-injury. Results demonstrated a reduction in myelin water fraction at 2 weeks post-injury in several brain areas relative to preseason scans, including the splenium of the corpus callosum, right posterior thalamic radiation, left superior corona radiata, left superior longitudinal fasciculus, and left posterior limb of the internal capsule. Myelin water fraction recovered to pre-season values by 2 months post-injury. These results may indicate transient myelin disruption following a single mTBI, with subsequent remyelination of affected neurons. Myelin disruption was not apparent in the athletes who did not experience a concussion, despite exposure to repetitive subconcussive trauma over a season of collegiate hockey. These findings may help to explain many of the metabolic and neurological deficits observed clinically following mTBI. PMID:26913900

  8. White Matter Tract Damage in the Behavioral Variant of Frontotemporal and Corticobasal Dementia Syndromes

    PubMed Central

    Tovar-Moll, Fernanda; de Oliveira-Souza, Ricardo; Bramati, Ivanei Edson; Zahn, Roland; Cavanagh, Alyson; Tierney, Michael; Moll, Jorge; Grafman, Jordan

    2014-01-01

    The phenotypes of the behavioral variant of frontotemporal dementia and the corticobasal syndrome present considerable clinical and anatomical overlap. The respective patterns of white matter damage in these syndromes have not been directly contrasted. Beyond cortical involvement, damage to white matter pathways may critically contribute to both common and specific symptoms in both conditions. Here we assessed patients with the behavioral variant of frontotemporal dementia and corticobasal syndrome with whole-brain diffusion tensor imaging to identify the white matter networks underlying these pathologies. Twenty patients with the behavioral variant of frontotemporal dementia, 19 with corticobasal syndrome, and 15 healthy controls were enrolled in the study. Differences in tract integrity between (i) patients and controls, and (ii) patients with the corticobasal syndrome and the behavioral variant of frontotemporal dementia were assessed with whole brain tract-based spatial statistics and analyses of regions of interest. Behavioral variant of frontotemporal dementia and the corticobasal syndrome shared a pattern of bilaterally decreased white matter integrity in the anterior commissure, genu and body of the corpus callosum, corona radiata and in the long intrahemispheric association pathways. Patients with the behavioral variant of frontotemporal dementia showed greater damage to the uncinate fasciculus, genu of corpus callosum and forceps minor. In contrast, corticobasal syndrome patients had greater damage to the midbody of the corpus callosum and perirolandic corona radiata. Whereas several compact white matter pathways were damaged in both the behavioral variant of frontotemporal dementia and corticobasal syndrome, the distribution and degree of white matter damage differed between them. These findings concur with the distinctive clinical manifestations of these conditions and may improve the in vivo neuroanatomical and diagnostic characterization of these disorders. PMID:25054218

  9. A significant risk factor for poststroke depression: the depression-related subnetwork

    PubMed Central

    Yang, Songran; Hua, Ping; Shang, Xinyuan; Cui, Zaixu; Zhong, Suyu; Gong, Gaolang; Humphreys, Glyn W.

    2015-01-01

    Background Despite being one of the direct causes of depression, whether stroke-induced neuroanatomical deterioration actually plays an important role in the onset of poststroke depression (PSD) is controversial. We assessed the structural basis of PSD, particularly with regard to white matter connectivity. Methods We evaluated lesion index, fractional anisotropy (FA) reduction and brain structural networks and then analyzed whole brain voxel-based lesions and FA maps. To understand brain damage in the context of brain connectivity, we used a graph theoretical approach. We selected nodes whose degree correlated with the Hamilton Rating Scale for Depression score (p < 0.05, false discovery rate–corrected), after controlling for age, sex, years of education, lesion size, Mini Mental State Examination score and National Institutes of Health Stroke Scale score. We used Poisson regression with robust standard errors to assess the contribution of the identified network toward poststroke major depression. Results We included 116 stroke patients in the study. Fourteen patients (12.1%) had diagnoses of major depression and 26 (22.4%) had mild depression. We found that lesions in the right insular cortex, left putamen and right superior longitudinal fasciculus as well as FA reductions in broader areas were all associated with major depression. Seventeen nodes were selected to build the depression-related subnetwork. Decreased local efficiency of the subnetwork was a significant risk factor for poststroke major depression (relative risk 0.84, 95% confidence interval 0.72–0.98, p = 0.027). Limitations The inability of DTI tractography to process fibre crossings may have resulted in inaccurate construction of white matter networks and affected statistical findings. Conclusion The present study provides, to our knowledge, the first graph theoretical analysis of white matter networks linked to poststroke major depression. These findings provide new insights into the neuroanatomical substrates of depression that develops after stroke. PMID:25871495

  10. Delay discounting behavior and white matter microstructure abnormalities in youth with a family history of alcoholism

    PubMed Central

    Herting, Megan M.; Schwartz, Daniel; Mitchell, Suzanne H.; Nagel, Bonnie J.

    2011-01-01

    Background Youth with family history of alcohol abuse have a greater risk of developing an alcohol use disorder (AUD). Brain and behavior differences may underlie this increased vulnerability. The current study examined delay discounting behavior and white matter microstructure in youth at high-risk for alcohol abuse, as determined by a family history of alcoholism (FH+), and youth without such family history (FH−). Methods Thirty-three healthy youth (FH+ = 15, FH− = 18), ages 11 to 15 years, completed a delay discounting task and underwent diffusion tensor imaging (DTI). Tract Based Spatial Statistics (Smith et al., 2006), as well as follow-up region-of-interest analyses, were performed in order to compare fractional anisotropy (FA) between FH+ and FH− youth. Results FH+ youth showed a trend toward increased discounting behavior and had significantly slower reaction times on the delay discounting paradigm compared to FH− youth. Group differences in FA were seen in several white matter tracts. Furthermore, lower FA in the left inferior longitudinal fasciculus and the right optic radiation statistically mediated the relationship between FH status and slower reaction times on the delay discounting task. Conclusion Youth with a family history of substance abuse have disrupted white matter microstructure, which likely contributes to less efficient cortical processing, and may act as an intrinsic risk-factor contributing to an increased susceptibility of developing AUD. In addition, FHP youth showed a trend toward greater impulsive decision making, possibly representing an inherent personal characteristic that may facilitate substance use onset and abuse in high-risk youth. PMID:20586754

  11. Inferring a dual-stream model of mentalizing from associative white matter fibres disconnection.

    PubMed

    Herbet, Guillaume; Lafargue, Gilles; Bonnetblanc, François; Moritz-Gasser, Sylvie; Menjot de Champfleur, Nicolas; Duffau, Hugues

    2014-03-01

    In the field of cognitive neuroscience, it is increasingly accepted that mentalizing is subserved by a complex frontotemporoparietal cortical network. Some researchers consider that this network can be divided into two distinct but interacting subsystems (the mirror system and the mentalizing system per se), which respectively process low-level, perceptive-based aspects and high-level, inference-based aspects of this sociocognitive function. However, evidence for this type of functional dissociation in a given neuropsychological population is currently lacking and the structural connectivities of the two mentalizing subnetworks have not been established. Here, we studied mentalizing in a large sample of patients (n = 93; 46 females; age range: 18-65 years) who had been resected for diffuse low-grade glioma-a rare tumour that migrates preferentially along associative white matter pathways. This neurological disorder constitutes an ideal pathophysiological model in which to study the functional anatomy of associative pathways. We mapped the location of each patient's resection cavity and residual lesion infiltration onto the Montreal Neurological Institute template brain and then performed multilevel lesion analyses (including conventional voxel-based lesion-symptom mapping and subtraction lesion analyses). Importantly, we estimated each associative pathway's degree of disconnection (i.e. the degree of lesion infiltration) and built specific hypotheses concerning the connective anatomy of the mentalizing subnetworks. As expected, we found that impairments in mentalizing were mainly related to the disruption of right frontoparietal connectivity. More specifically, low-level and high-level mentalizing accuracy were correlated with the degree of disconnection in the arcuate fasciculus and the cingulum, respectively. To the best of our knowledge, our findings constitute the first experimental data on the structural connectivity of the mentalizing network and suggest the existence of a dual-stream hodological system. Our results may lead to a better understanding of disorders that affect social cognition, especially in neuropathological conditions characterized by atypical/aberrant structural connectivity, such as autism spectrum disorders. PMID:24519980

  12. Associations of White Matter Microstructure with Clinical and Demographic Characteristics in Heavy Drinkers

    PubMed Central

    Monnig, Mollie A.; Yeo, Ronald A.; Tonigan, J. Scott; McCrady, Barbara S.; Thoma, Robert J.; Sabbineni, Amithrupa; Hutchison, Kent E.

    2015-01-01

    Damage to the brain’s white matter is a signature injury of alcohol use disorders (AUDs), yet understanding of risks associated with clinical and demographic characteristics is incomplete. This study investigated alcohol problem severity, recent drinking behavior, and demographic factors in relation to white matter microstructure in heavy drinkers. Magnetic resonance imaging (MRI) scans, including diffusion tensor imaging (DTI), were collected from 324 participants (mean age = 30.9 ± 9.1 years; 30% female) who reported five or more heavy drinking episodes in the past 30 days. Drinking history and alcohol problem severity were assessed. A common white matter factor was created from fractional anisotropy (FA) values of five white matter tracts: body of corpus callosum, fornix, external capsule, superior longitudinal fasciculus, and cingulate gyrus. Previous research has implicated these tracts in heavy drinking. Structural equation modeling (SEM) analyses tested the hypothesis that, after controlling for duration of alcohol exposure, clinical and behavioral measures of alcohol use severity would be associated with lower white matter factor scores. Potential interactions with smoking status, gender, age, treatment-seeking status, and depression or anxiety symptoms also were tested. Controlling for number of years drinking, greater alcohol problem severity and recent drinking frequency were significantly associated with lower white matter factor scores. The effect of drinking frequency differed significantly for men and women, such that higher drinking frequency was linked to lower white matter factor scores in women but not in men. In conclusion, alcohol problem severity was a significant predictor of lower white matter FA in heavy drinkers, after controlling for duration of alcohol exposure. In addition, more frequent drinking contributed to lower FA in women but not men, suggesting gender-specific vulnerability to alcohol neurotoxicity. PMID:26529515

  13. Bridging the gap between perceptual and cognitive perspectives on absolute pitch.

    PubMed

    Elmer, Stefan; Rogenmoser, Lars; Kühnis, Jürg; Jäncke, Lutz

    2015-01-01

    Absolute pitch (AP) refers to the rare ability to identify the chroma of a tone or to produce a specific pitch without reference to keyality (e.g., G or C). Previously, AP has been proposed to rely on the distinctive functional-anatomical architecture of the left auditory-related cortex (ARC), this specific trait possibly enabling an optimized early "categorical perception". In contrast, currently prevailing models of AP postulate that cognitive rather than perceptual processes, namely "pitch labeling" mechanisms, more likely constitute the bearing skeleton of AP. This associative memory component has previously been proposed to be dependent, among other mechanisms, on the recruitment of the left dorsolateral prefrontal cortex (DLPFC) as well as on the integrity of the left arcuate fasciculus, a fiber bundle linking the posterior supratemporal plane with the DLPFC. Here, we attempted to integrate these two apparently conflicting perspectives on AP, namely early "categorical perception" and "pitch labeling". We used electroencephalography and evaluated resting-state intracranial functional connectivity between the left ARC and DLPFC in a sample of musicians with and without AP. Results demonstrate significantly increased left-hemispheric theta phase synchronization in AP compared with non-AP musicians. Within the AP group, this specific electrophysiological marker was predictive of absolute-hearing behavior and explained ?30% of variance. Thus, we propose that in AP subjects the tonal inputs and the corresponding mnemonic representations are tightly coupled in such a manner that the distinctive electrophysiological signature of AP can saliently be detected in only 3 min of resting-state measurements. PMID:25568128

  14. Brainstem neuropathology in a mouse model of Niemann-Pick disease type C.

    PubMed

    Luan, Zhuo; Saito, Yoshiaki; Miyata, Hajime; Ohama, Eisaku; Ninomiya, Haruaki; Ohno, Kousaku

    2008-05-15

    Niemann-Pick disease type C (NPC) is a neurovisceral lipid storage disorder characterized by progressive and widespread neurodegeneration. Although some characteristic symptoms of NPC result from brainstem dysfunction, little information is available about which brainstem structures are affected. In this study, the brainstems of mutant BALB/c NPC1-/- mice with a retroposon insertion in the NPC1 gene were examined for neuropathological changes. In the midbrain, the integrated optic density (IOD) and cell count density of tyrosine-hydroxylase (TH) immunostained neurons were decreased in the substantia nigra. In the pons, TH immunoreactivity in the locus ceruleus (LC) neurons was decreased, while the IOD and the neuronal density of choline acetyltransferase (ChAT)-immunostained neurons in the pedunculopontine tegmental nucleus were preserved. The ChAT immunoreactivity of the hypoglossal nucleus (12N) neurons was not decreased, but Klüver-Barrera staining showed that neuronal density in the nucleus of the solitary tract (NTS) was decreased. Klüver-Barrera and neuronal nuclei (NeuN) staining showed a decrease in neuronal density in the ventral cochlear nucleus, but not in the dorsal cochlear nucleus. Gliosis was widely identified by GFAP staining in various brainstem structures, including the superior and inferior colliculi, the rostral interstitial nucleus of the medial longitudinal fasciculus, the oculomotor complex, the medial geniculate nucleus, the nucleus ambiguus, and the 12N. However, GFAP expression was not augmented in the LC, the cochlear nucleus, or the NTS. These neuropathological findings suggest a basis for the neurological syndromes observed in NPC, such as rigidity, oculomotor symptoms, cataplexy and sleep disturbance, dysphagia, and perceptive deafness. PMID:18190929

  15. White Matter Microstructure in Individuals at Clinical High Risk of Psychosis: A Whole-Brain Diffusion Tensor Imaging Study

    PubMed Central

    Clemm von Hohenberg, Christian; Pasternak, Ofer; Kubicki, Marek; Ballinger, Thomas; Vu, Mai-Anh; Swisher, Tali; Green, Katie; Giwerc, Michelle; Dahlben, Brian; Goldstein, Jill M.; Woo, Tsung-Ung W.; Petryshen, Tracey L.; Mesholam-Gately, Raquelle I.; Woodberry, Kristen A.; Thermenos, Heidi W.; Mulert, Christoph; McCarley, Robert W.; Seidman, Larry J.; Shenton, Martha E.

    2014-01-01

    Background: The study of individuals at clinical high risk (CHR) for psychosis provides an important opportunity for unraveling pathological mechanisms underlying schizophrenia and related disorders. A small number of diffusion tensor magnetic resonance imaging (DTI) studies in CHR samples have yielded anatomically inconsistent results. The present study is the first to apply tract-based spatial statistics (TBSS) to perform a whole-brain DTI analysis in CHR subjects. Methods: A total of 28 individuals meeting CHR criteria and 34 healthy controls underwent DTI. TBSS was used for a group comparison of fractional anisotropy (FA), as well as axial, radial, and mean diffusivity (AD, RD, and MD). Conversion to psychosis was monitored during a mean follow-up period of 12.3 months. Results: The rate of conversion to psychosis was relatively low (4%). TBSS revealed increased MD in several clusters in the right hemisphere, most notably in the superior longitudinal fasciculus (SLF), posterior corona radiata, and corpus callosum (splenium and body). Increased RD was restricted to a smaller area in the posterior parietal lobe. Conclusion: We present further evidence that white matter microstructure is abnormal in CHR individuals, even in a sample in which the vast majority do not transition to psychosis over the following year. In accord with previous studies on CHR individuals and patients with early-onset schizophrenia, our findings suggest an important pathological role for the parietal lobe and especially the SLF. The latter is known to undergo particularly dynamic microstructural changes during adolescence and early adulthood, a critical phase for the development of psychotic illness. PMID:23737549

  16. Poorer frontolimbic white matter integrity is associated with chronic cannabis use, FAAH genotype, and increased depressive and apathy symptoms in adolescents and young adults

    PubMed Central

    Shollenbarger, Skyler G.; Price, Jenessa; Wieser, Jon; Lisdahl, Krista

    2015-01-01

    Background The heaviest period of cannabis use coincides with ongoing white matter (WM) maturation. Further, cannabis-related changes may be moderated by FAAH genotype (rs324420). We examined the association between cannabis use and FAAH genotype on frontolimbic WM integrity in adolescents and emerging adults. We then tested whether observed WM abnormalities were linked with depressive or apathy symptoms. Methods Participants included 37 cannabis users and 37 healthy controls (33 female; ages 18–25). Multiple regressions examined the independent and interactive effects of variables on WM integrity. Results Regular cannabis users demonstrated reduced WM integrity in the bilateral uncinate fasciculus (UNC) (MD, right: p = .009 and left: p = .009; FA, right: p = .04 and left: p = .03) and forceps minor (fMinor) (MD, p = .03) compared to healthy controls. Marginally reduced WM integrity in the cannabis users was found in the left anterior thalamic radiation (ATR) (FA, p = .08). Cannabis group ? FAAH genotype interaction predicted WM integrity in bilateral ATR (FA, right: p = .05 and left: p = .001) and fMinor (FA, p = .02). In cannabis users, poorer WM integrity was correlated with increased symptoms of depression and apathy in bilateral ATR and UNC. Conclusions Consistent with prior findings, cannabis use was associated with reduced frontolimbic WM integrity. WM integrity was also moderated by FAAH genotype, in that cannabis-using FAAH C/C carriers and A carrying controls had reduced WM integrity compared to control C/C carriers. Observed frontolimbic white matter abnormalities were linked with increased depressive and apathy symptoms in the cannabis users. PMID:26106535

  17. Speech repetition as a window on the neurobiology of auditory-motor integration for speech: A voxel-based lesion symptom mapping study.

    PubMed

    Rogalsky, Corianne; Poppa, Tasha; Chen, Kuan-Hua; Anderson, Steven W; Damasio, Hanna; Love, Tracy; Hickok, Gregory

    2015-05-01

    For more than a century, speech repetition has been used as an assay for gauging the integrity of the auditory-motor pathway in aphasia, thought classically to involve a linkage between Wernicke's area and Broca's area via the arcuate fasciculus. During the last decade, evidence primarily from functional imaging in healthy individuals has refined this picture both computationally and anatomically, suggesting the existence of a cortical hub located at the parietal-temporal boundary (area Spt) that functions to integrate auditory and motor speech networks for both repetition and spontaneous speech production. While functional imaging research can pinpoint the regions activated in repetition/auditory-motor integration, lesion-based studies are needed to infer causal involvement. Previous lesion studies of repetition have yielded mixed results with respect to Spt's critical involvement in speech repetition. The present study used voxel-based lesion symptom mapping (VLSM) to investigate the neuroanatomy of repetition of both real words and non-words in a sample of 47 patients with focal left hemisphere brain damage. VLSMs identified a large voxel cluster spanning gray and white matter in the left temporal-parietal junction, including area Spt, where damage was significantly related to poor non-word repetition. Repetition of real words implicated a very similar dorsal network including area Spt. Cortical regions including Spt were implicated in repetition performance even when white matter damage was factored out. In addition, removing variance associated with speech perception abilities did not alter the overall lesion pattern for either task. Together with past functional imaging work, our results suggest that area Spt is integral in both word and non-word repetition, that its contribution is above and beyond that made by white matter pathways, and is not driven by perceptual processes alone. These findings are highly consistent with the claim that Spt is an area of sensory-motor translation in speech processing. PMID:25777496

  18. Diffusion Tensor Imaging of Parkinson’s Disease, Multiple System Atrophy and Progressive Supranuclear Palsy: A Tract-Based Spatial Statistics Study

    PubMed Central

    Worker, Amanda; Blain, Camilla; Jarosz, Jozef; Chaudhuri, K. Ray; Barker, Gareth J.; Williams, Steve C. R.; Brown, Richard G.; Leigh, P. Nigel; Dell’Acqua, Flavio; Simmons, Andrew

    2014-01-01

    Although often clinically indistinguishable in the early stages, Parkinson’s disease (PD), Multiple System Atrophy (MSA) and Progressive Supranuclear Palsy (PSP) have distinct neuropathological changes. The aim of the current study was to identify white matter tract neurodegeneration characteristic of each of the three syndromes. Tract-based spatial statistics (TBSS) was used to perform a whole-brain automated analysis of diffusion tensor imaging (DTI) data to compare differences in fractional anisotropy (FA) and mean diffusivity (MD) between the three clinical groups and healthy control subjects. Further analyses were conducted to assess the relationship between these putative indices of white matter microstructure and clinical measures of disease severity and symptoms. In PSP, relative to controls, changes in DTI indices consistent with white matter tract degeneration were identified in the corpus callosum, corona radiata, corticospinal tract, superior longitudinal fasciculus, anterior thalamic radiation, superior cerebellar peduncle, medial lemniscus, retrolenticular and anterior limb of the internal capsule, cerebral peduncle and external capsule bilaterally, as well as the left posterior limb of the internal capsule and the right posterior thalamic radiation. MSA patients also displayed differences in the body of the corpus callosum corticospinal tract, cerebellar peduncle, medial lemniscus, anterior and superior corona radiata, posterior limb of the internal capsule external capsule and cerebral peduncle bilaterally, as well as the left anterior limb of the internal capsule and the left anterior thalamic radiation. No significant white matter abnormalities were observed in the PD group. Across groups, MD correlated positively with disease severity in all major white matter tracts. These results show widespread changes in white matter tracts in both PSP and MSA patients, even at a mid-point in the disease process, which are not found in patients with PD. PMID:25405990

  19. Diffusion tensor imaging of Parkinson's disease, multiple system atrophy and progressive supranuclear palsy: a tract-based spatial statistics study.

    PubMed

    Worker, Amanda; Blain, Camilla; Jarosz, Jozef; Chaudhuri, K Ray; Barker, Gareth J; Williams, Steve C R; Brown, Richard G; Leigh, P Nigel; Dell'Acqua, Flavio; Simmons, Andrew

    2014-01-01

    Although often clinically indistinguishable in the early stages, Parkinson's disease (PD), Multiple System Atrophy (MSA) and Progressive Supranuclear Palsy (PSP) have distinct neuropathological changes. The aim of the current study was to identify white matter tract neurodegeneration characteristic of each of the three syndromes. Tract-based spatial statistics (TBSS) was used to perform a whole-brain automated analysis of diffusion tensor imaging (DTI) data to compare differences in fractional anisotropy (FA) and mean diffusivity (MD) between the three clinical groups and healthy control subjects. Further analyses were conducted to assess the relationship between these putative indices of white matter microstructure and clinical measures of disease severity and symptoms. In PSP, relative to controls, changes in DTI indices consistent with white matter tract degeneration were identified in the corpus callosum, corona radiata, corticospinal tract, superior longitudinal fasciculus, anterior thalamic radiation, superior cerebellar peduncle, medial lemniscus, retrolenticular and anterior limb of the internal capsule, cerebral peduncle and external capsule bilaterally, as well as the left posterior limb of the internal capsule and the right posterior thalamic radiation. MSA patients also displayed differences in the body of the corpus callosum corticospinal tract, cerebellar peduncle, medial lemniscus, anterior and superior corona radiata, posterior limb of the internal capsule external capsule and cerebral peduncle bilaterally, as well as the left anterior limb of the internal capsule and the left anterior thalamic radiation. No significant white matter abnormalities were observed in the PD group. Across groups, MD correlated positively with disease severity in all major white matter tracts. These results show widespread changes in white matter tracts in both PSP and MSA patients, even at a mid-point in the disease process, which are not found in patients with PD. PMID:25405990

  20. Injury to white matter tracts in relapsing–remitting multiple sclerosis: A possible therapeutic window within the first 5 years from onset using diffusion-tensor imaging tract-based spatial statistics

    PubMed Central

    Asaf, Achiron; Evan, Stone; Anat, Achiron

    2015-01-01

    DTI studies in multiple sclerosis (MS) reveal white matter (WM) injury that occurs with disease progression. In the present study we aimed to elucidate the relationship of microstructural WM damage in patients with varying periods of disease duration. DTI scans were acquired from 90 MS patients and 25 healthy controls. Patients were grouped to short (<1 year), moderate (1 up to 6 years) and long (6–10 years) disease duration periods. Statistical analyses of the fractional anisotropy (FA) data were performed using tract-based spatial statistics (TBSS). Whole-brain skeletal FA measurements showed a significant decrease between healthy controls and the short MS disease duration group, as well as between moderate disease duration and long disease duration groups, but failed to show a significant difference between short and moderate disease duration groups. Voxelwise analysis revealed clusters of diffuse FA reductions in 40 WM tracts when comparing healthy controls and MS short disease duration group, with the point of maximal significant difference located in the left inferior longitudinal fasciculus. Comparing short with long disease duration groups, progressive FA reduction was demonstrated across 30 WM tracts, with the point of maximal significant difference migrating to the body of the corpus callosum. A non-linear pattern of WM microstructure disruption occurs in RRMS. Alterations are seen early in the disease course within 1 year from onset, reach a plateau within the next 5 years, and only later additional WM changes are detected. An important period of a possible therapeutic window therefore exists within the early disease stage. PMID:26106550

  1. White Matter Alterations at 33-Year Follow-Up in Adults with Childhood Attention-Deficit/Hyperactivity Disorder

    PubMed Central

    Cortese, Samuele; Imperati, Davide; Zhou, Juan; Proal, Erika; Klein, Rachel G.; Mannuzza, Salvatore; Ramos-Olazagasti, Maria A.; Milham, Michael P.; Kelly, Clare; Castellanos, F. Xavier

    2013-01-01

    Background Attention-Deficit/Hyperactivity Disorder (ADHD) is increasingly conceived as reflecting altered functional and structural brain connectivity. The latter can be addressed with diffusion tensor imaging (DTI). We examined fractional anisotropy (FA), a DTI index related to white matter structural properties, in adult males diagnosed with ADHD in childhood (probands) and matched comparisons without childhood ADHD. Additionally, we contrasted FA among probands with and without current ADHD in adulthood and comparisons. Methods Participants were from an original cohort of 207 boys and 178 male comparisons. At 33-year follow-up, analyzable DTI scans were obtained in 51 probands (41.3±2.8 yrs) and 66 comparisons (41.2±3.1 yrs). Voxel-based FA was computed using tract-based spatial statistics (TBSS), controlling for multiple comparisons. Results Probands with childhood ADHD exhibited significantly lower FA than comparisons without childhood ADHD in the right superior and posterior corona radiata, right superior longitudinal fasciculus, and in a left cluster including the posterior thalamic radiation, the retrolenticular part of the internal capsule, and the sagittal stratum (p<0.05, corrected). FA was significantly decreased relative to comparisons in several tracts in both probands with current and remitted ADHD, who did not differ significantly from each other. FA was not significantly increased in probands in any region. Conclusions Decreased FA in adults with childhood ADHD regardless of current ADHD may be an enduring trait of ADHD. White matter tracts with decreased FA connect regions involved in high-level as well as sensorimotor functions, suggesting that both types of processes are involved in the pathophysiology of ADHD. PMID:23566821

  2. GENE NETWORK EFFECTS ON BRAIN MICROSTRUCTURE AND INTELLECTUAL PERFORMANCE IDENTIFIED IN 472 TWINS

    PubMed Central

    Chiang, Ming-Chang; Barysheva, Marina; McMahon, Katie L.; de Zubicaray, Greig I.; Johnson, Kori; Montgomery, Grant W.; Martin, Nicholas G.; Toga, Arthur W.; Wright, Margaret J.; Shapshak, Paul; Thompson, Paul M.

    2012-01-01

    A major challenge in neuroscience is finding which genes affect brain integrity, connectivity, and intellectual function. Discovering influential genes holds vast promise for neuroscience, but typical genome-wide searches assess around one million genetic variants one-by-one, leading to intractable false positive rates, even with vast samples of subjects. Even more intractable is the question of which genes interact and how they work together to affect brain connectivity. Here we report a novel approach that discovers which genes contribute to brain wiring and fiber integrity at all pairs of points in a brain scan. We studied genetic correlations between thousands of points in human brain images from 472 twins and their non-twin siblings (mean age: 23.7±2.1 SD years; 193 M/279 F). We combined clustering with genome-wide scanning to find brain systems with common genetic determination. We then filtered the image in a new way to boost power to find causal genes. Using network analysis, we found a network of genes that affect brain wiring in healthy young adults. Our new strategy makes it more computationally tractable to discover genes that affect brain integrity. The gene network showed small-world and scale-free topologies, suggesting efficiency in genetic interactions, and resilience to network disruption. Genetic variants at hubs of the network influence intellectual performance by modulating associations between performance intelligence quotient (IQ) and the integrity of major white matter tracts, such as the callosal genu and splenium, cingulum, optic radiations, and the superior longitudinal fasciculus. PMID:22723713

  3. Blocking central pathways in the primate motor system using high-frequency sinusoidal current

    PubMed Central

    Fisher, Karen M.; Jillani, Ngalla E.; Oluoch, George O.

    2014-01-01

    Electrical stimulat