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1

Regional white matter development in children with autism spectrum disorders.  

PubMed

In this pilot study the severity of autism spectrum disorders (ASD) was associated with alterations in white matter development. Children with ASD and without ASD were assessed by magnetic resonance imaging (MRI) for their myelination development on a regional basis. Measures were obtained in medial frontal cortex, temporal poles, and temporo-parietal junction in both left and right hemispheres. Children with ASD showed myelination that was greater than expected for their age in both left and right medial frontal cortex and showed myelination that was less than expected in left temporo-parietal junction. The severity of ASD symptoms, as assessed by the Autism Diagnostic Observation Schedule-Generic, was associated more with left hemisphere alterations than right hemisphere. PMID:20564327

Carmody, Dennis P; Lewis, Michael

2010-12-01

2

Diffusion Tensor Magnetic Resonance Imaging of Disruption of Regional White Matter in Schizophrenia  

Microsoft Academic Search

Diffusion tensor imaging provides a new approach for quantifying anisotropic diffusion of white matter in vivo. We used this technique to investigate subtle disruption of regional white matter in schizophrenia. Twelve patients with schizophrenia were compared with 11 healthy controls. Psychotic symptoms were assessed using the Positive and Negative Syndrome Scale. A significant fractional anisotropy (FA) reduction was found in

T. Minami; K. Nobuhara; G. Okugawa; K. Takase; T. Yoshida; S. Sawada; S. Ha-Kawa; K. Ikeda; T. Kinoshita

2003-01-01

3

Regional variation, hemispheric asymmetries and gender differences in pericortical white matter.  

PubMed

Brain white matter tissue composition can be quantified using Diffusion Tensor Imaging (DTI) and Magnetization Transfer Imaging (MTI). Fractional Anisotropy (FA), derived from DTI, indexes the integrity, density and organization of axons. Magnetization Transfer Ratio (MTR), derived from MTI, indexes to the presence of cell membranes and myelin. The combined use of FA and MTR provides a more complete picture of white matter structure than either imaging modality in isolation. Here we describe the regional distribution of FA and MTR measurements of pericortical white matter in 56 young, healthy right-handed subjects. Significant regional and lobar differences are seen for both measures along with a significant gender difference in FA. Highly consistent hemispheric asymmetries in FA and MTR were observed, suggesting that the greater fiber coherence and increased myelination of fibers in left hemisphere perisylvian regions may provide a structural basis for left-hemisphere language dominance. PMID:21397700

Kang, Xiaojian; Herron, Timothy J; Woods, David L

2011-03-22

4

AGE-RELATED CHANGES IN THE MESIAL TEMPORAL LOBE: THE PARAHIPPOCAMPAL WHITE MATTER REGION  

PubMed Central

The perforant pathway originates from cells in the entorhinal cortex and relays sensory information from the neocortex to the hippocampus, a region critical for memory function. Imaging studies have demonstrated structural alterations in the parahippocampal white matter in the region of the perforant pathway in people at risk for developing Alzheimer’s disease. It is not clear, however, if changes noted in this region are indicative of pathological aging or are a function of the normal aging process. We compared MRI-derived mesial temporal lobe volumes in 51 healthy older individuals and 40 young participants, with an emphasis on the parahippocampal white matter. Yearly clinical evaluations showed that 9 of the older cohort declined in cognitive function. Parahippocampal white matter, hippocampal and entorhinal cortex volumes were significantly reduced in healthy older people who remained stable over time compared to young participants. These findings suggest that volume differences in mesial temporal lobe gray and white matter structures may take place as a result of the normative aging process.

Stoub, T.R.; Barnes, C.A.; Shah, R.C.; Stebbins, G.T.; Ferrari, C.; deToledo-Morrell, L.

2011-01-01

5

White matter lesions in Fabry disease occur in 'prior' selectively hypometabolic and hyperperfused brain regions.  

PubMed

Fabry disease is an X-linked disorder associated with early onset stroke. We previously found a significantly elevated cerebral blood flow (CBF) in patients with Fabry disease. We set to determine whether elevated resting CBF in Fabry disease is primarily a cerebrovascular abnormality or is secondary to enhanced neuronal metabolism. The relationship of cerebral metabolism and blood flow to Fabry leukoencephalopathy was also investigated. We measured the global and regional cerebral metabolic rate of glucose using 18-fluoro-deoxyglucose (FDG) and PET in 16 patients with Fabry disease (7 patients with leukoaraiotic lesions and 9 without) and in 7 control subjects. MRI fluid attenuated inversion recovery (FLAIR) studies were also performed in the patient and control groups. All control subjects had normal MRI FLAIR studies with no high-signal deep white matter lesions (WML). Patients were partitioned into FLAIR lesion and non-FLAIR lesion groups. We found no evidence of cerebral glucose hypermetabolism in Fabry disease. On the contrary, significantly decreased regional cerebral glucose metabolism (rCMRGlu) was found particularly in the deep white matter in the Fabry non-lesion group and exacerbated in the lesion group. Lesion-susceptible regions were relatively hyperperfused in non-lesion patients compared to the control group. We conclude that the elevated rCBF and decreased white matter rCMRGlu indicates a dissociation between metabolism and blood flow suggesting chronic deep white matter metabolic insufficiency. PMID:14698356

Moore, David F; Altarescu, Gheona; Barker, W Craig; Patronas, Nicholas J; Herscovitch, Peter; Schiffmann, Raphael

2003-12-30

6

Aging White Matter and Cognition: Differential Effects of Regional Variations in Diffusion Properties on Memory, Executive Functions, and Speed  

ERIC Educational Resources Information Center

|Disruption of cerebral white matter has been proposed as an explanation for age-related cognitive declines. However, the role of specific regions in specific cognitive declines remains unclear. We used diffusion tensor imaging to examine the associations between regional microstructural integrity of the white matter and performance on…

Kennedy, Kristen M.; Raz, Naftali

2009-01-01

7

Regional Gray Matter, White Matter, and Cerebrospinal Fluid Distributions in Schizophrenic Patients, Their Siblings, and Controls  

Microsoft Academic Search

ter volume and significant increases in ventricular CSF volume. Regional effects were most robust when com- ponent volumes were expressed as percentages of over- all regional volumes; in this case, for patient and sibling groups, gray matter volume reductions and sulcal CSF volume increases were significantly more pronounced in the frontal and temporal lobes than in the remainder of the

Tyrone D. Cannon; Theo G. M. van Erp; Matti Huttunen; Jouko Lonnqvist; Oili Salonen; Leena Valanne; Veli-Pekka Poutanen; Raquel E. Gur; Michelle Yan

1998-01-01

8

Regional differences in relationships between apparent white matter integrity, cognition and mood in patients with ischemic stroke  

Microsoft Academic Search

White matter changes are one potential etiology of behavioral changes in cerebrovascular disease. Whole brain diffusion tensor imaging–fractional anisotropy (DTI-FA) as a measure of apparent white matter integrity is related to cognitive function in cerebrovascular disease. However, white matter changes are not uniform, nor are their effects. We examine the relationship between regional differences in DTI-FA and cognition and mood

John Williamson; David Nyenhuis; Glenn T. Stebbins; Damon Lamb; Vaidas Simkus; Kumar Sripathirathan; Changsheng Wang; Leyla deToledo-Morrell; Philip Gorelick

2010-01-01

9

Regional cortical white matter reductions in velocardiofacial syndrome: a volumetric MRI analysis  

Microsoft Academic Search

Background: Velocardiofacial syndrome, caused by a microdeletion on chromosome 22q.11, is associated with craniofacial anomalies, cardiac defects, learning disabilities, and psychiatric disorders. To understand how the 22q.11 deletion affects brain development, this study examined gray and white matter volumes in major lobar brain regions of children with velocardiofacial syndrome relative to control subjects.Methods: Subjects were ten children with velocardiofacial syndrome

Wendy R Kates; Courtney P Burnette; Ethylin W Jabs; Julie Rutberg; Anne M Murphy; Marco Grados; Michael Geraghty; Walter E Kaufmann; Godfrey D Pearlson

2001-01-01

10

The brain in chronic CRPS pain: Abnormal gray-white matter interactions in emotional and autonomic regions  

PubMed Central

Summary Chronic complex regional pain syndrome (CRPS) is a debilitating pain condition accompanied by autonomic abnormalities. We investigated gray matter morphometry and white matter anisotropy in CRPS patients and matched controls. Patients exhibited 1) a disrupted relationship between white matter anisotropy and whole-brain gray matter volume, 2) gray matter atrophy in a single cluster encompassing right insula, right ventromedial prefrontal cortex (VMPFC), and right nucleus accumbens, and 3) a decrease in fractional anisotropy in the left cingulum-callosal bundle. Reorganization of white matter connectivity in these regions was characterized by branching pattern alterations, and increased (VMPFC to insula) and decreased connectivity (VMPFC to basal ganglion). While regional atrophy differentially related to pain intensity and duration, the strength of connectivity between specific atrophied regions related to anxiety. These abnormalities encompass emotional, autonomic, and pain perception regions, implying that they likely play a critical role in the global clinical picture of CRPS.

Geha, Paul Y.; Baliki, Marwan N.; Harden, R. Norman; Bauer, William R.; Parrish, Todd B.; Apkarian, A. Vania

2008-01-01

11

Aging white matter and cognition: differential effects of regional variations in diffusion properties on memory, executive functions, and speed.  

PubMed

Disruption of cerebral white matter has been proposed as an explanation for age-related cognitive declines. However, the role of specific regions in specific cognitive declines remains unclear. We used diffusion tensor imaging to examine the associations between regional microstructural integrity of the white matter and performance on age-sensitive cognitive tasks in a sample of healthy adults (N=52, age 19-81 years). White matter integrity was assessed by fractional anisotropy (FA) and apparent diffusion coefficient (ADC) in multiple regions of interest (genu and splenium of corpus callosum, internal capsule limbs, prefrontal, temporal, superior/posterior parietal, occipital white matter) and related to processing speed, working memory, inhibition, task switching, and episodic memory. We found that age and regional white matter integrity differentially influenced cognitive performance. Age-related degradation in anterior brain areas was associated with decreased processing speed and poorer working memory, whereas reduced inhibition and greater task switching costs were linked to decline in posterior areas. Poorer episodic memory was associated with age-related differences in central white matter regions. The observed multiple dissociations among specific age-sensitive cognitive skills and their putative neuroanatomical substrates support the view that age-related cognitive declines are unlikely to stem from a single cause. PMID:19166865

Kennedy, Kristen M; Raz, Naftali

2009-01-08

12

Identification of brain white matter regions for diagnosis of Alzheimer using Diffusion Tensor Imaging.  

PubMed

Diffusion Tensor Imaging (DTI) technique is widely used to probe the white matter (WM) tracts, which is affected most by neurological disorders. The fractional anisotropy (FA) metric has been used predominantly to study changes in the WM tracts. Here an attempt is made to delineate specific regions of interest in the WM that may be probable indicators for the diagnosis of Alzheimer disease (AD). Genetic algorithm has been used as feature reduction method along with Adaptive Boosting (AdaBoost) machine learning technique to determine the most prominent regions in the WM that are indicators of AD. It is found in this study that Fornix region of WM is most affected by Alzheimer. Further, classification was done to differentiate between Alzheimer and Normal controls with accuracy of 84.5%. The results obtained were validated by comparing with the existing literature on Alzheimer. PMID:24111239

Patil, Ravindra B; Piyush, Ranjan; Ramakrishnan, S

2013-07-01

13

Regional white matter hyperintensity volume, not hippocampal atrophy, predicts incident Alzheimer disease in the community.  

PubMed

BACKGROUND New-onset Alzheimer disease (AD) is often attributed to degenerative changes in the hippocampus. However, the contribution of regionally distributed small vessel cerebrovascular disease, visualized as white matter hyperintensities (WMHs) on magnetic resonance imaging, remains unclear. OBJECTIVE To determine whether regional WMHs and hippocampal volume predict incident AD in an epidemiological study. DESIGN A longitudinal community-based epidemiological study of older adults from northern Manhattan, New York. SETTING The Washington Heights/Inwood Columbia Aging Project. PARTICIPANTS Between 2005 and 2007, 717 participants without dementia received magnetic resonance imaging scans. A mean (SD) of 40.28 (9.77) months later, 503 returned for follow-up clinical examination and 46 met criteria for incident dementia (45 with AD). Regional WMHs and relative hippocampal volumes were derived. Three Cox proportional hazards models were run to predict incident dementia, controlling for relevant variables. The first included all WMH measurements; the second included relative hippocampal volume; and the third combined the 2 measurements. MAIN OUTCOME MEASURE Incident AD. RESULTS White matter hyperintensity volume in the parietal lobe predicted time to incident dementia (hazard ratio [HR] = 1.194; P = .03). Relative hippocampal volume did not predict incident dementia when considered alone (HR = 0.419; P = .77) or with the WMH measures included in the model (HR = 0.302; P = .70). Including hippocampal volume in the model did not notably alter the predictive utility of parietal lobe WMHs (HR = 1.197; P = .049). CONCLUSIONS The findings highlight the regional specificity of the association of WMHs with AD. It is not clear whether parietal WMHs solely represent a marker for cerebrovascular burden or point to distinct injury compared with other regions. Future work should elucidate pathogenic mechanisms linking WMHs and AD pathology. PMID:22945686

Brickman, Adam M; Provenzano, Frank A; Muraskin, Jordan; Manly, Jennifer J; Blum, Sonja; Apa, Zoltan; Stern, Yaakov; Brown, Truman R; Luchsinger, José A; Mayeux, Richard

2012-12-01

14

Neuroimaging Predictors of Cognitive Impairment in Confluent White Matter Lesion: Volumetric Analyses of 99 Brain Regions  

Microsoft Academic Search

Background: Although confluent white matter lesion (WML) is associated with cognitive impairment, the mechanism explaining this association is controversial. We aimed to investigate comprehensively the MRI predictors of cognitive impairment in confluent WML. Methods: Among 45 lacunar stroke patients who had confluent WML, we evaluated the association of executive function [Mattis Dementia Rating Scale – Initiation\\/Perseveration subscale (MDRS I\\/P)] and

Vincent C. T. Mok; Tianming Liu; Wynnie W. M. Lam; Adrian Wong; Xintao Hu; Lei Guo; Xiang Yan Chen; Wai Kwong Tang; Ka Sing Wong; Stephen Wong

2008-01-01

15

Quantitative in vivo evidence for broad regional gradients in the timing of white matter maturation during adolescence  

PubMed Central

A fundamental tenet in the field of developmental neuroscience is that brain maturation generally proceeds from posterior/inferior to anterior/superior. This pattern is thought to underlie the similar timing of cognitive development in related domains, with the dorsal frontal cortices – important for decision making and cognitive control – the last to fully mature. While this caudal to rostral wave of structural development was first qualitatively described for white matter in classical postmortem studies, and has been discussed frequently in the developmental neuroimaging literature and in the popular press, it has never been formally demonstrated continuously and quantitatively across the whole brain with magnetic resonance imaging (MRI). Here we use diffusion imaging to map developmental changes in the white matter in 32 typically-developing individuals age 5-28 years. We then employ a novel meta-statistic that is sensitive to the timing of this developmental trajectory, and use this integrated strategy to both confirm these long-postulated broad regional gradients in the timing of white matter maturation in vivo, and demonstrate a surprisingly smooth transition in the timing of white matter maturational peaks along a caudal-rostral arc in this cross-sectional sample. These results provide further support for the notion of continued plasticity in these regions well into adulthood, and may provide a new approach for the investigation of neurodevelopmental disorders that could alter the timing of this typical developmental sequence.

Colby, John B.; Van Horn, John D.; Sowell, Elizabeth R.

2010-01-01

16

Regional Variation in Brain White Matter Diffusion Index Changes following Chemoradiotherapy: A Prospective Study Using Tract-Based Spatial Statistics  

PubMed Central

Purpose There is little known about how brain white matter structures differ in their response to radiation, which may have implications for radiation-induced neurocognitive impairment. We used diffusion tensor imaging (DTI) to examine regional variation in white matter changes following chemoradiotherapy. Methods Fourteen patients receiving two or three weeks of whole-brain radiation therapy (RT) ± chemotherapy underwent DTI pre-RT, at end-RT, and one month post-RT. Three diffusion indices were measured: fractional anisotropy (FA), radial diffusivity (RD), and axial diffusivity (AD). We determined significant individual voxel changes of diffusion indices using tract-based spatial statistics, and mean changes of the indices within fourteen white matter structures of interest. Results Voxels of significant FA decreases and RD increases were seen in all structures (p<0.05), with the largest changes (20–50%) in the fornix, cingula, and corpus callosum. There were highly significant between-structure differences in pre-RT to end-RT mean FA changes (p<0.001). The inferior cingula had a mean FA decrease from pre-RT to end-RT significantly greater than 11 of the 13 other structures (p<0.00385). Conclusions Brain white matter structures varied greatly in their response to chemoradiotherapy as measured by DTI changes. Changes in FA and RD related to white matter demyelination were prominent in the cingula and fornix, structures relevant to radiation-induced neurocognitive impairment. Future research should evaluate DTI as a predictive biomarker of brain chemoradiotherapy adverse effects.

Chapman, Christopher H.; Nazem-Zadeh, Mohammad; Lee, Oliver E.; Schipper, Matthew J.; Tsien, Christina I.; Lawrence, Theodore S.; Cao, Yue

2013-01-01

17

Human Brain White Matter Atlas: Identification and Assignment of Common Anatomical Structures in Superficial White Matter  

PubMed Central

Structural delineation and assignment are the fundamental steps in understanding the anatomy of the human brain. The white matter has been structurally defined in the past only at its core regions (deep white matter). However, the most peripheral white matter areas, which are interleaved between the cortex and the deep white matter, have lacked clear anatomical definitions and parcellations. We used axonal fiber alignment information from diffusion tensor imaging (DTI) to delineate the peripheral white matter, and investigated its relationship with the cortex and the deep white matter. Using DTI data from 81 healthy subjects, we identified nine common, blade-like anatomical regions, which were further parcellated into 21 subregions based on the cortical anatomy. Four short association fiber tracts connecting adjacent gyri (U-fibers) were also identified reproducibly among the healthy population. We anticipate that this atlas will be useful resource for atlas-based white matter anatomical studies.

Oishi, Kenichi; Zilles, Karl; Amunts, Katrin; Faria, Andreia; Jiang, Hangyi; Li, Xin; Akhter, Kazi; Hua, Kegang; Woods, Roger; Toga, Arthur W.; Pike, G. Bruce; Rosa-Neto, Pedro; Evans, Alan; Zhang, Jiangyang; Huang, Hao; Miller, Michael I.; van Zijl, Peter C.M.; Mazziotta, John; Mori, Susumu

2008-01-01

18

Inflammatory response and chemokine expression in the white matter corpus callosum and gray matter cortex region during cuprizone-induced demyelination.  

PubMed

Brain inflammation plays a central role in multiple sclerosis (MS). Besides lymphocytes, the astroglia and microglia mainly contribute to the cellular composition of the inflammatory infiltrate in MS lesions. Several studies were able to demonstrate that cortical lesions are characterized by lower levels of inflammatory cells among activated microglia/macrophages. The underlying mechanisms for this difference, however, remain to be clarified. In the current study, we compared the kinetics and extent of microglia and astrocyte activation during early and late cuprizone-induced demyelination in the white matter tract corpus callosum and the telencephalic gray matter. Cellular parameters were related to the expression profiles of the chemokines Ccl2 and Ccl3. We are clearly able to demonstrate that both regions are characterized by early oligodendrocyte stress/apoptosis with concomitant microglia activation and delayed astrocytosis. The extent of microgliosis/astrocytosis appeared to be greater in the subcortical white matter tract corpus callosum compared to the gray matter cortex region. The same holds true for the expression of the key chemokines Ccl2 and Ccl3. The current study defines a model to study early microglia activation and to investigate differences in the neuroinflammatory response of white vs. gray matter. PMID:22528463

Buschmann, J P; Berger, K; Awad, H; Clarner, T; Beyer, C; Kipp, M

2012-04-22

19

Differential language expertise related to white matter architecture in regions subserving sensory-motor coupling, articulation, and interhemispheric transfer.  

PubMed

The technique of diffusion tensor imaging (DTI) has been used to investigate alterations in white matter architecture following long-term training and expertise. Professional simultaneous interpreters (SI) provide an ideal model for the investigation of training-induced plasticity due to the high demands placed on sound to motor mapping mechanisms, which are vital for executing fast interpretations. In line with our hypothesis, we found clusters with decreased fractional anisotropy (FA) in the SI group in brain regions previously shown to support sensory-motor coupling mechanisms and speech articulation (cluster extent family-wise error corrected, P < 0.01). Furthermore, we found an altered white matter architecture indicated by lower FA values in the SI group in the most anterior and posterior parts of the corpus callosum. Our results suggest that language expertise is accompanied by plastic adaptations in regions strongly involved in motor aspects of speech and in interhemispheric information transfer. These results have implications for our understanding of language expertise in relation to white matter adaptations. PMID:21162044

Elmer, Stefan; Hänggi, Jürgen; Meyer, Martin; Jäncke, Lutz

2010-12-15

20

New Light on White Matter  

Microsoft Academic Search

njury of central white matter is a major cause of func- tional disability in cerebrovascular disease. White matter is a target of hypoxic-ischemic injury throughout life, in clinical settings ranging from periventricular leukomalacia in the neonatal period, stroke and cardiac arrest in adults, to vascular dementia in the aging brain. The traditional view from animal studies is that gray matter

Mark P. Goldberg; Bruce R. Ransom

2010-01-01

21

On the elemental composition of suspended matter of the Severnaya Dvina River (White Sea region)  

NASA Astrophysics Data System (ADS)

New data on the elemental composition of the Severnaya Dvina River, the largest one in the White Sea region, are presented. The elemental composition of the river water in May, the period of the snowmelt flood, is similar to the upper layer of the Earth’s continental crust due to the active erosion of the earth material in the catchment area. In August, the period of the summer low water, the impact of biogenic components increases and elevated concentrations of Cd, Sb, Mn, Zn, Pb, and Cu are observed. At other times, no significant pollution by heavy and rare-earth elements is registered.

Shevchenko, V. P.; Pokrovsky, O. S.; Filippov, A. S.; Lisitsyn, A. P.; Bobrov, V. A.; Bogunov, A. Yu.; Zavernina, N. N.; Zolotykh, E. O.; Isaeva, A. B.; Kokryatskaya, N. M.; Korobov, V. B.; Kravchishina, M. D.; Novigatsky, A. N.; Politova, N. V.

2010-02-01

22

Regional differences between grey and white matter in cuprizone induced demyelination.  

PubMed

Cuprizone feeding is a commonly used model to study experimental de- and remyelination, with the corpus callosum being the most frequently investigated white matter tract. We have previously shown that demyelination is also extensive in the cerebral cortex in the cuprizone model. In the current study, we have performed a detailed analysis of the dynamics of demyelination in the cortex in comparison to the corpus callosum. Prominent and almost complete demyelination in the corpus callosum was observed after 4.5-5 weeks of 0.2% cuprizone feeding, whereas complete cortical demyelination was only observed after 6 weeks of cuprizone feeding. Interestingly, remyelination in the corpus callosum occurred even before the termination of cuprizone administration. Accumulation of microglia in the corpus callosum started as early as week 3 reaching its maximum at week 4.5 and was still significantly elevated at week 6 of cuprizone treatment. Within the cortex only a few scattered activated microglial cells were found. Furthermore, the intensity of astrogliosis, accumulation of oligodendrocyte progenitor cells and nestin positive cells differed between the two areas investigated. The time course and dynamics of demyelination differ in the corpus callosum and in the cortex, suggesting different underlying pathomechanisms. PMID:19524552

Gudi, Viktoria; Moharregh-Khiabani, Darius; Skripuletz, Thomas; Koutsoudaki, Paraskevi N; Kotsiari, Alexandra; Skuljec, Jelena; Trebst, Corinna; Stangel, Martin

2009-06-12

23

White matter injury detection in neonatal MRI  

NASA Astrophysics Data System (ADS)

Early detection of white matter injury in premature newborns can facilitate timely clinical treatments reducing the potential risk of later developmental deficits. It was reported that there were more than 5% premature newborns in British Columbia, Canada, among which 5-10% exhibited major motor deficits and 25-50% exhibited significant developmental and visual deficits. With the advancement of computer assisted detection systems, it is possible to automatically identify white matter injuries, which are found inside the grey matter region of the brain. Atlas registration has been suggested in the literature to distinguish grey matter from the soft tissues inside the skull. However, our subjects are premature newborns delivered at 24 to 32 weeks of gestation. During this period, the grey matter undergoes rapid changes and differs significantly from one to another. Besides, not all detected white spots represent injuries. Additional neighborhood information and expert input are required for verification. In this paper, we propose a white matter feature identification system for premature newborns, which is composed of several steps: (1) Candidate white matter segmentation; (2) Feature extraction from candidates; (3) Validation with data obtained at a later stage on the children; and (4) Feature confirmation for automated detection. The main challenge of this work lies in segmenting white matter injuries from noisy and low resolution data. Our approach integrates image fusion and contrast enhancement together with a fuzzy segmentation technique to achieve promising results. Other applications, such as brain tumor and intra-ventricular haemorrhage detection can also benefit from our approach.

Cheng, Irene; Hajari, Nasim; Firouzmanesh, Amirhossein; Shen, Rui; Miller, Steven; Poskitt, Ken; Basu, Anup

2013-02-01

24

Unconfined compression of white matter.  

PubMed

The porous properties of brain tissue are important for understanding normal and abnormal cerebrospinal fluid flow in the brain. In this study, a poroviscoelastic model was fitted to the stress relaxation response of white matter in unconfined compression performed under a range of low strain rates. A set of experiments was also performed on the tissue samples using a no-slip boundary condition. Results from these experiments demonstrated that the rheological response of the white matter is primarily governed by the intrinsic viscoelastic properties of the solid phase. The permeability of white matter was found to be of the order of 10(-12) m4/Ns. PMID:16376349

Cheng, Shaokoon; Bilston, Lynne E

2005-12-22

25

Cerebral White Matter  

PubMed Central

Lesions of the cerebral white matter (WM) result in focal neurobehavioral syndromes, neuropsychiatric phenomena, and dementia. The cerebral WM contains fiber pathways that convey axons linking cerebral cortical areas with each other and with subcortical structures, facilitating the distributed neural circuits that subserve sensorimotor function, intellect, and emotion. Recent neuroanatomical investigations reveal that these neural circuits are topographically linked by five groupings of fiber tracts emanating from every neocortical area: (1) cortico-cortical association fibers; (2) corticostriatal fibers; (3) commissural fibers; and cortico-subcortical pathways to (4) thalamus and (5) pontocerebellar system, brain stem, and/or spinal cord. Lesions of association fibers prevent communication between cortical areas engaged in different domains of behavior. Lesions of subcortical structures or projection/striatal fibers disrupt the contribution of subcortical nodes to behavior. Disconnection syndromes thus result from lesions of the cerebral cortex, subcortical structures, and WM tracts that link the nodes that make up the distributed circuits. The nature and the severity of the clinical manifestations of WM lesions are determined, in large part, by the location of the pathology: discrete neurological and neuropsychiatric symptoms result from focal WM lesions, whereas cognitive impairment across multiple domains—WM dementia—occurs in the setting of diffuse WM disease. We present a detailed review of the conditions affecting WM that produce these neurobehavioral syndromes, and consider the pathophysiology, clinical effects, and broad significance of the effects of aging and vascular compromise on cerebral WM, in an attempt to help further the understanding, diagnosis, and treatment of these disorders.

Schmahmann, Jeremy D.; Smith, Eric E.; Eichler, Florian S.; Filley, Christopher M.

2013-01-01

26

White Matter Microstructure and Cognitive Function  

PubMed Central

In recent years, diffusion-weighted magnetic resonance imaging (DW-MRI) has been increasingly used to explore the relationship between white matter structure and cognitive function. This technique uses the passive diffusion of water molecules to infer properties of the surrounding tissue. DW-MRI has been extensively employed to investigate how individual differences in behavior are related to variability in white matter microstructure on a range of different cognitive tasks and also to examine the effect experiential learning might have on brain structural connectivity. Using diffusion tensor tractography, large white matter pathways have been traced in vivo and used to explore patterns of white matter projections between different brain regions. Recent findings suggest that diffusion-weighted imaging might even be used to measure functional differences in water diffusion during task performance. This review describes some research highlights in diffusion-weighted imaging and how this technique can be employed to further our understanding of cognitive function.

Anderson, Elaine J.; Husain, Masud

2013-01-01

27

Evidence for white matter abnormalities in schizophrenia  

PubMed Central

Purpose of review The purpose of this review is to highlight important recent imaging, histological, and genetic findings relevant to white matter abnormalities in schizophrenia. It is cast within the context of research findings conducted over the last 5 years, where we analyze their importance in understanding schizophrenia, as well as discuss future directions for research. Recent findings White matter abnormalities have long been hypothesized in schizophrenia, although only recently has it become possible to investigate them more closely. This has come about as a result of advances in neuroimaging, including new imaging techniques sensitive to white matter structure, as well as advances in computer science, with new analysis techniques making it possible to evaluate several interconnected brain regions at a time. Postmortem studies, with advances such as fluoroscopy and electron microscopy, have also led to quantifying populations of different brain cells, including myelin-forming oligodendrocytes. Moreover, molecular studies enable examination of immunoreactivity of proteins that are responsible for building myelin sheaths. Additionally, microarray genetic studies allow us to investigate myelin-related genes in schizophrenia. Taken together, these technological advances bring us closer to understanding white matter pathology in schizophrenia. Summary Advances in new imaging techniques likely account for the renewed interest in investigating white matter abnormalities in schizophrenia, with over 30 new articles published on this topic in the last 12 months, compared with 11 the year before. We review recent imaging, histological, and genetic findings that suggest white matter abnormalities in schizophrenia.

Kubicki, Marek; McCarley, Robert W.; Shenton, Martha E.

2009-01-01

28

Regional white matter volume and the relation with attentional functioning in survivors of malignant pediatric brain tumors  

NASA Astrophysics Data System (ADS)

Quantitative assessment of MR examinations in 37 survivors of childhood cancer treated with central nervous system prophylaxis revealed that normal appearing white matter (NAWM) volume is associated with attention-related problems, localized specifically in the right prefrontal region. T1-, T2-, and PD-weighted images were segmented and divided into pre-frontal, frontal, parietal/temporal, and parietal/occipital regions for each hemisphere. These eight regions were analyzed in five slices centered at the level of the basal ganglia. The patient"s age at diagnosis and time elapsed from diagnosis were used as covariates in the regressions. Attentional measures showed significant deficiency when compared to age and gender normative values. Total, frontal and/or prefrontal NAWM volumes from the range of slices examined were significantly associated with 5 of the 8 attentional measures. The frontal/prefrontal region of the brain is associated with executive functioning tasks and could potentially be spared as much as possible during therapy planning. The results of the present study further support the contention that NAWM is an important substrate for treatment-induced neurocognitive problems among survivors of malignant brain tumors of childhood.

Glass, John O.; Mulhern, Raymond K.; White, Holly A.; Wilkinson, Gina M.; Reddick, Wilburn E.

2003-05-01

29

Regional differences in susceptibility to hypoxic-ischemic injury in the preterm brain: exploring the spectrum from white matter loss to selective grey matter injury in a rat model.  

PubMed

Models of premature brain injury have largely focused on the white matter injury thought to underlie periventricular leukomalacia (PVL). However, with increased survival of very low birth weight infants, injury patterns involving grey matter are now recognized. We aimed to determine how grey matter lesions relate to hypoxic-ischemic- (HI) mediated white matter injury by modifying our rat model of PVL. Following HI, microglial infiltration, astrocytosis, and neuronal and axonal degeneration increased in a region-specific manner dependent on the severity of myelin loss in pericallosal white matter. The spectrum of injury ranged from mild, where diffuse white matter abnormalities were dominant and were associated with mild axonal injury and local microglial activation, to severe HI injury characterized by focal MBP loss, widespread neuronal degeneration, axonal damage, and gliosis throughout the neocortex, caudate putamen, and thalamus. In sum, selective regional white matter loss occurs in the preterm rat concomitantly with a clinically relevant spectrum of grey matter injury. These data demonstrate an interspecies similarity of brain injury patterns and further substantiates the reliable use of this model for the study of preterm brain injury. PMID:22530125

Selip, D B; Jantzie, L L; Chang, M; Jackson, M C; Fitzgerald, E C; Boll, G; Murphy, A; Jensen, F E

2012-03-15

30

Canavan Disease: A White Matter Disorder  

ERIC Educational Resources Information Center

|Breakdown of oligodendrocyte-neuron interactions in white matter (WM), such as the loss of myelin, results in axonal dysfunction and hence a disruption of information processing between brain regions. The major feature of leukodystrophies is the lack of proper myelin formation during early development or the onset of myelin loss late in life.…

Kumar, Shalini; Mattan, Natalia S.; de Vellis, Jean

2006-01-01

31

SCIENCE MATTERS Hooded Sweatshirt (White)  

NSDL National Science Digital Library

White, heavy duty 9.3 oz. 50/50 blend, double-lined hood and pockets. Sweatshirt is printed with Science Matters logo on front and NSTA logo on back. Available in Adult sizes: Small, Medium, Large, X Large, XX Large.

1900-01-01

32

Update on genetic disorders affecting white matter  

Microsoft Academic Search

The classification of diseases affecting white matter has changed dramatically with the use of magnetic resonance imaging. Classical leukodystrophies, such as metachromatic leukodystrophy and Krabbe’s disease, account for only a small number of inherited diseases that affect white matter. Magnetic resonance imaging has clarified genetic disorders that result in white matter changes or leukoencephalopathies. The term leukoencephalopathy is used to

Edward M Kaye

2001-01-01

33

Gender Differences in White Matter Microstructure  

Microsoft Academic Search

BackgroundSexual dimorphism in human brain structure is well recognised, but little is known about gender differences in white matter microstructure. We used diffusion tensor imaging to explore differences in fractional anisotropy (FA), an index of microstructural integrity.MethodsA whole brain analysis of 135 matched subjects (90 men and 45 women) using a 1.5 T scanner. A region of interest (ROI) analysis

Richard A. Kanaan; Matthew Allin; Marco Picchioni; Gareth J. Barker; Eileen Daly; Sukhwinder S. Shergill; James Woolley; Philip K. McGuire

2012-01-01

34

Multiple sclerosis and allied white matter diseases  

Microsoft Academic Search

Advanced magnetic resonance imaging (MRI) approaches are extensively used for the assessment of central nervous system (CNS)\\u000a damage in patients with multiple sclerosis (MS) and allied white matter diseases. Through their ability to obtain simultaneous\\u000a measures of abnormalities of structure and function at a global and regional level, these techniques, which include magnetization\\u000a transfer MRI, diffusion tensor MRI and proton

Massimo Filippi; Maria Assunta Rocca

2008-01-01

35

Regional changes in brain gray and white matter in patients with schizophrenia demonstrated with voxel-based analysis of MRI  

Microsoft Academic Search

This study examined regional structural changes in the whole brain in 45 medicated patients with schizophrenia (23 males and 22 females), comparing with 42 age- and sex-matched healthy volunteers (22 males and 20 females). Automated voxel-based analysis on three-dimensional magnetic resonance imaging (MRI) was conducted using statistical parametric mapping (SPM). Compared with the controls, relative gray matter in the patients

Michio Suzuki; Shigeru Nohara; Hirofumi Hagino; Kenzo Kurokawa; Takashi Yotsutsuji; Yasuhiro Kawasaki; Tsutomu Takahashi; Mie Matsui; Naoto Watanabe; Hikaru Seto; Masayoshi Kurachi

2002-01-01

36

White matter tractography using diffusion tensor deflection  

Microsoft Academic Search

Diffusion tensor MRI provides unique directional diffusion information that can be used to estimate the patterns of white matter connectivity in the human brain. In this study, the behavior of an algorithm for white matter tractography is examined. The algorithm, called TEND, uses the entire diffusion tensor to deflect the estimated fiber trajectory. Simulations and imaging experiments on in vivo

Mariana Lazar; David M. Weinstein; Jay S. Tsuruda; Khader M. Hasan; Konstantinos Arfanakis; M. Elizabeth Meyerand; Benham Badie; Howard A. Rowley; Victor Haughton; Aaron Field; Andrew L. Alexander

2003-01-01

37

Astrocytes and Developmental White Matter Disorders  

ERIC Educational Resources Information Center

|There is an increasing awareness that the astrocytes in the immature periventricular white matter are vulnerable to ischemia and respond to inflammation. Here we provide a synopsis of the articles that have evaluated the causes and consequences of developmental brain injuries to white matter astrocytes as well as the consequences of several…

Sen, Ellora; Levison, Steven W.

2006-01-01

38

Traumatic white matter injury and toxic leukoencephalopathies.  

PubMed

White matter injury may be secondary to a range of neurodegenerative disorders, such as the common dementing disorders of the elderly, or may be a consequence of specific white matter disorders, such as multiple sclerosis and the rare leukodystrophies. This article will focus on two relatively common primary groups of disorders of the white matter, traumatic white matter injury and toxic leukoencephalopathies. Traumatic axonal injury may be focal or diffuse, and is associated with a clinical spectrum ranging from concussion through to coma and death. The molecular mechanisms underlying axonal degeneration secondary to traumatic axonal degeneration are being elucidated and may give an insight into potential therapeutic targets. Toxic leukoencephalopathy may be secondary to exposure to a wide range of compounds, including chemotherapeutic drugs. These toxins may produce white matter injury through a range of mechanisms, and the potential toxic effects of compounds need to be considered when assessing a patient with a nonspecific leukoencephalopathy. PMID:21864077

Al-Hasani, Omer Hussain; Smith, Colin

2011-09-01

39

Whole brain-based analysis of regional white matter tract alterations in rare motor neuron diseases by diffusion tensor imaging.  

PubMed

Different motor neuron disorders (MNDs) are mainly defined by the clinical presentation based on the predominance of upper or lower motor neuron impairment and the course of the disease. Magnetic resonance imaging (MRI) mostly serves as a tool to exclude other pathologies, but novel approaches such as diffusion tensor imaging (DTI) have begun to add information on the underlying pathophysiological processes of these disorders in vivo. The present study was designed to investigate three different rare MNDs, i.e., primary lateral sclerosis (PLS, N = 25), hereditary spastic paraparesis (HSP, N = 24), and X-linked spinobulbar muscular atrophy (X-SBMA, N = 20), by use of whole-brain-based DTI analysis in comparison with matched controls. This analysis of white matter (WM) impairment revealed widespread and characteristic patterns of alterations within the motor system with a predominant deterioration of the corticospinal tract (CST) in HSP and PLS patients according to the clinical presentation and also in patients with X-SBMA to a lesser degree, but also WM changes in projections to the limbic system and within distinct areas of the corpus callosum (CC), the latter both for HSP and PLS. In summary, DTI was able to define a characteristic WM pathoanatomy in motor and extra-motor brain areas, such as the CC and the limbic projectional system, for different MNDs via whole brain-based FA assessment and quantitative fiber tracking. Future advanced MRI-based investigations might help to provide a fingerprint-identification of MNDs. PMID:20336652

Unrath, Alexander; Müller, Hans-Peter; Riecker, Axel; Ludolph, Albert C; Sperfeld, Anne-Dorte; Kassubek, Jan

2010-11-01

40

Vesicular release of glutamate from unmyelinated axons in white matter  

Microsoft Academic Search

Directed fusion of transmitter-laden vesicles enables rapid intercellular signaling in the central nervous system and occurs at synapses within gray matter. Here we show that action potentials also induce the release of glutamate from axons in the corpus callosum, a white matter region responsible for interhemispheric communication. Callosal axons release glutamate by vesicular fusion, which induces quantal AMPA receptor–mediated currents

Jennifer L Ziskin; Akiko Nishiyama; Maria Rubio; Masahiro Fukaya; Dwight E Bergles

2007-01-01

41

Frontal white matter microstructure, aggression, and impulsivity in men with schizophrenia: a preliminary study  

Microsoft Academic Search

Background: Aggression and impulsivity may involve altered frontal white matter.Methods: Axial diffusion tensor images were acquired in 14 men with schizophrenia using a pulsed gradient, double spin echo, echo planar imaging method. White matter microstructural measures (fractional anisotropy and trace) were calculated from these data. Regions of interest were placed in frontal white matter on four slices. Impulsivity was measured

Matthew J. Hoptman; Jan Volavka; Glyn Johnson; Elisabeth Weiss; Robert M. Bilder; Kelvin O. Lim

2002-01-01

42

Lower Orbital Frontal White Matter Integrity in Adolescents with Bipolar I Disorder  

ERIC Educational Resources Information Center

|Patients with bipolar I disorder demonstrated white matter abnormalities in white matter regions as seen through the use of diffusion tensor imaging. The findings suggest that white matter abnormalities in pediatric bipolar disorder may be useful in constructing neurobiological models of the disorder.|

Kafantaris, Vivian; Kingsley, Peter; Ardekani, Babak; Saito, Ema; Lencz, Todd; Lim, Kelvin; Szeszko, Philip

2009-01-01

43

DT-MRI White Matter Fiber Tractography with Global Constraints: An Unsupervised Learning Approach  

Microsoft Academic Search

Brain white matter fiber tracking imaging using diffusion tensor magnetic resonance imaging (DT-MRI) traces brain white matter fiber bundle and reconstruct the structures of the fibers according to the diffusion of water molecular in the white matter. In this paper, a novel fiber tracking technique based on well established unsupervised learning algorithms was proposed. For a pair of regions of

Xi Wu; Wuzhong Bi; Jingyu Zhu; Tong Zhu

2009-01-01

44

Magnetization transfer measurements of cerebral white matter in patients with myotonic dystrophy  

Microsoft Academic Search

To determine whether patients with myotonic dystrophy (MyD) have structural changes in the cerebral white matter, we performed magnetization transfer (MT) imaging of the cerebral white matter in 14 MyD patients and 11 age-matched normal controls. We calculated MT ratios in both the white matter lesions (WMLs) and the normal-appearing white matter (NAWM) of MyD patients using region of interest

Hiromitsu Naka; Yukari Imon; Tomohiko Ohshita; Kie Honjo; Takeshi Kitamura; Yasuyo Mimori; Shigenobu Nakamura

2002-01-01

45

Gender Differences in White Matter Microstructure  

PubMed Central

Background Sexual dimorphism in human brain structure is well recognised, but little is known about gender differences in white matter microstructure. We used diffusion tensor imaging to explore differences in fractional anisotropy (FA), an index of microstructural integrity. Methods A whole brain analysis of 135 matched subjects (90 men and 45 women) using a 1.5 T scanner. A region of interest (ROI) analysis was used to confirm those results where proximity to CSF raised the possibility of partial-volume artefact. Results Men had higher fractional anisotropy (FA) in cerebellar white matter and in the left superior longitudinal fasciculus; women had higher FA in the corpus callosum, confirmed by ROI. Discussion The size of the differences was substantial - of the same order as that attributed to some pathology – suggesting gender may be a potentially significant confound in unbalanced clinical studies. There are several previous reports of difference in the corpus callosum, though they disagree on the direction of difference; our findings in the cerebellum and the superior longitudinal fasciculus have not previously been noted. The higher FA in women may reflect greater efficiency of a smaller corpus callosum. The relatively increased superior longitudinal fasciculus and cerebellar FA in men may reflect their increased language lateralisation and enhanced motor development, respectively.

Kanaan, Richard A.; Allin, Matthew; Picchioni, Marco; Barker, Gareth J.; Daly, Eileen; Shergill, Sukhwinder S.; Woolley, James; McGuire, Philip K.

2012-01-01

46

Aerobic Fitness is Associated with Gray Matter Volume and White Matter Integrity in Multiple Sclerosis  

PubMed Central

Alterations in gray and white matter have been well documented in individuals with multiple sclerosis. Severity and extent of such brain tissue damage have been associated with cognitive impairment, disease duration and neurological disability, making quantitative indices of tissue damage important markers of disease progression. In this study, we investigated the association between cardiorespiratory fitness and measures of gray matter atrophy and white matter integrity. Employing a voxel-based approach to analyses of gray matter and white matter, we specifically examined whether higher levels of fitness in multiple sclerosis participants were associated with preserved gray matter volume and integrity of white matter. We found a positive association between cardiorespiratory fitness and regional gray matter volumes and higher focal fractional anisotropy values. Statistical mapping revealed that higher levels of fitness were associated with greater gray matter volume in the midline cortical structures including the medial frontal gyrus, anterior cingulate cortex and the precuneus. Further, we also found increasing levels of fitness were associated with higher fractional anisotropy in the left thalamic radiation and right anterior corona radiata. Both preserved gray matter volume and white-matter tract integrity were associated with better performance on measures of processing speed. Taken together, these results suggest that fitness exerts a prophylactic influence on the cerebral atrophy observed early on preserving neuronal integrity in multiple sclerosis, thereby reducing long-term disability.

Prakash, Ruchika Shaurya; Snook, Erin M.; Motl, Robert W.; Kramer, Arthur F.

2009-01-01

47

Linking white matter integrity loss to associated cortical regions using structural connectivity information in Alzheimer's disease and fronto-temporal dementia: the Loss in Connectivity (LoCo) score.  

PubMed

It is well known that gray matter changes occur in neurodegenerative diseases like Alzheimer's (AD) and fronto-temporal dementia (FTD), and several studies have investigated their respective patterns of atrophy progression. Recent work, however, has revealed that diffusion MRI that is able to detect white matter integrity changes may be an earlier or more sensitive biomarker in both diseases. However, studies that examine white matter changes only are limited in that they do not provide the functional specificity of GM region-based analysis. In this study, we develop a new metric called the Loss in Connectivity (LoCo) score that gives the amount of structural network disruption incurred by a gray matter region for a particular pattern of white matter integrity loss. Leveraging the relative strengths of WM and GM markers, this metric links areas of WM integrity loss to their connected GM regions as a first step in understanding their functional implications. The LoCo score is calculated for three groups: 18AD, 18 FTD, and 19 age-matched normal controls. We show significant correlations of the LoCo with the respective atrophy patterns in AD (R=0.51, p=2.2 × 10(-9)) and FTD (R=0.49, p=2.5 × 10(-8)) for a standard 116 region gray matter atlas. In addition, we demonstrate that the LoCo outperforms a measure of gray matter atrophy when classifying individuals into AD, FTD, and normal groups. PMID:22484307

Kuceyeski, Amy; Zhang, Yu; Raj, Ashish

2012-03-20

48

Developmental Differences in White Matter Architecture Between Boys and Girls  

PubMed Central

Previous studies have found developmental differences between males and females in brain structure. During childhood and adolescence, relative white matter volume increases faster in boys than in girls. Sex differences in the development of white matter microstructure were investigated in a cohort of normal children ages 5-18 in a cross-sectional diffusion tensor imaging (DTI) study. Greater fractional anisotropy (FA) in boys was shown in associative white matter regions (including the frontal lobes), while greater FA in girls was shown in the splenium of the corpus callosum. Greater mean diffusivity (MD) in boys was shown in the corticospinal tract and in frontal white matter in the right hemisphere; greater MD in girls was shown in occipito-parietal regions and the most superior aspect of the corticospinal tract in the right hemisphere. Significant sex-age interactions on FA and MD were also shown. Girls displayed a greater rate of fiber density increase with age compared with boys in associative regions (reflected in MD values). However girls displayed a trend toward increased organization with age (reflected in FA values) only in the right hemisphere, while boys displayed this trend only in the left hemisphere. These results indicate differing developmental trajectories in white matter for boys and girls and the importance of taking sex into account in developmental DTI studies. The results also may have implications for the study of the relationship of brain architecture with intelligence.

Schmithorst, Vincent J.; Holland, Scott K.; Dardzinski, Bernard J.

2007-01-01

49

White matter hyperintensities and working memory: an explorative study.  

PubMed

White matter hyperintensities (WMH) are commonly observed in elderly people and may have the most profound effect on executive functions, including working memory. Surprisingly, the Digit Span backward, a frequently employed working memory task, reveals no association with WMH. In the present study, it was investigated whether more detailed analyses of WMH variables and study sample selection are important when establishing a possible relationship between the Digit Span backward and WMH. To accomplish this, the Digit Span backward and additional working memory tests, WMH subscores, and cardiovascular risk factors were examined. The results revealed that performance on the Digit Span backward test is unrelated to WMH, whereas a relationship between other working memory tests and WMH was confirmed. Furthermore, a division between several white matter regions seems important; hyperintensities in the frontal deep white matter regions were the strongest predictor of working memory performance. PMID:18421629

Oosterman, Joukje M; Van Harten, Barbera; Weinstein, Henry C; Scheltens, Philip; Sergeant, Joseph A; Scherder, Erik J A

2008-05-01

50

White matter heritability using diffusion tensor imaging in neonatal brains.  

PubMed

Understanding genetic and environmental effects on white matter development in the first years of life is of great interest, as it provides insights into the etiology of neurodevelopmental disorders. In this study, the genetic and environmental effects on white matter were estimated using data from 173 neonatal twin subjects. Diffusion tensor imaging scans were acquired around 40 days after birth and were non-rigidly registered to a group-specific atlas and parcellated into 98 ROIs. A model of additive genetic, and common and specific environmental variance components was used to estimate overall and regional genetic and environmental contributions to diffusion parameters of fractional anisotropy, radial diffusivity, and axial diffusivity. Correlations between the regional heritability values and diffusion parameters were also examined. Results indicate that individual differences in overall white matter microstructure, represented by the average diffusion parameters over the whole brain, are heritable, and estimates are higher than found in studies in adults. Estimates of genetic and environmental variance components vary considerably across different white matter regions. Significant positive correlations between radial diffusivity heritability and radial diffusivity values are consistent with regional genetic variation being modulated by maturation status in the neonatal brain: the more mature the region is, the less genetic variation it shows. Common environmental effects are present in a few regions that tend to be characterized by low radial diffusivity. Results from the joint diffusion parameter analysis suggest that multivariate modeling approaches might be promising to better estimate maturation status and its relationship with genetic and environmental effects. PMID:22856369

Geng, Xiujuan; Prom-Wormley, Elizabeth C; Perez, Javier; Kubarych, Thomas; Styner, Martin; Lin, Weili; Neale, Michael C; Gilmore, John H

2012-06-01

51

White matter abnormalities in gene-positive myoclonus-dystonia.  

PubMed

Myoclonus-dystonia is an autosomal dominantly inherited movement disorder clinically characterized by myoclonic jerks and dystonic movements of the upper body. Functional imaging and structural gray matter imaging studies in M-D suggest defective sensorimotor integration and an association between putaminal volume and severity of dystonia, possibly because of neuronal plasticity. As we expect changes in the connections between the cortical and subcortical regions, we performed a combination of white matter voxel-based morphometry (wVBM) and diffusion tensor imaging (DTI) to detect macro- and microstructural white matter changes, respectively, in DYT-11 mutations carriers (M-D). Sixteen clinically affected DYT-11 mutation carriers and 18 control subjects were scanned with 3-Tesla MRI to compare white matter volume, fractional anisotropy, and mean diffusivity between groups. In DYT11 mutation carriers, increased white matter volume and FA and decreased mean diffusivity were found in the subthalamic area of the brain stem, including the red nucleus. Furthermore, decreased mean diffusivity was found in the subgyral cortical sensorimotor areas. The white matter changes found in the subthalamic area of the brain stem, connecting the cerebellum with the thalamus, are compatible with the hypothesis that abnormal function in M-D involves a network that includes the cerebellum, brain stem, and basal ganglia. Whether these changes are causative or an effect of M-D requires further study. PMID:23114862

van der Meer, Johan N; Beukers, Richard J; van der Salm, S M A; Caan, Matthan W A; Tijssen, Marina A J; Nederveen, Aart J

2012-10-31

52

Alterations in white matter microstructure in neurofibromatosis-1.  

PubMed

Neurofibromatosis (NF1) represents the most common single gene cause of learning disabilities. NF1 patients have impairments in frontal lobe based cognitive functions such as attention, working memory, and inhibition. Due to its well-characterized genetic etiology, investigations of NF1 may shed light on neural mechanisms underlying such difficulties in the general population or other patient groups. Prior neuroimaging findings indicate global brain volume increases, consistent with neural over-proliferation. However, little is known about alterations in white matter microstructure in NF1. We performed diffusion tensor imaging (DTI) analyses using tract-based spatial statistics (TBSS) in 14 young adult NF1 patients and 12 healthy controls. We also examined brain volumetric measures in the same subjects. Consistent with prior studies, we found significantly increased overall gray and white matter volume in NF1 patients. Relative to healthy controls, NF1 patients showed widespread reductions in white matter integrity across the entire brain as reflected by decreased fractional anisotropy (FA) and significantly increased absolute diffusion (ADC). When radial and axial diffusion were examined we found pronounced differences in radial diffusion in NF1 patients, indicative of either decreased myelination or increased space between axons. Secondary analyses revealed that FA and radial diffusion effects were of greatest magnitude in the frontal lobe. Such alterations of white matter tracts connecting frontal regions could contribute to the observed cognitive deficits. Furthermore, although the cellular basis of these white matter microstructural alterations remains to be determined, our findings of disproportionately increased radial diffusion against a background of increased white matter volume suggest the novel hypothesis that one potential alteration contributing to increased cortical white matter in NF1 may be looser packing of axons, with or without myelination changes. Further, this indicates that axial and radial diffusivity can uniquely contribute as markers of NF1-associated brain pathology in conjunction with the typically investigated measures. PMID:23094098

Karlsgodt, Katherine H; Rosser, Tena; Lutkenhoff, Evan S; Cannon, Tyrone D; Silva, Alcino; Bearden, Carrie E

2012-10-19

53

Alterations in White Matter Microstructure in Neurofibromatosis-1  

PubMed Central

Neurofibromatosis (NF1) represents the most common single gene cause of learning disabilities. NF1 patients have impairments in frontal lobe based cognitive functions such as attention, working memory, and inhibition. Due to its well–characterized genetic etiology, investigations of NF1 may shed light on neural mechanisms underlying such difficulties in the general population or other patient groups. Prior neuroimaging findings indicate global brain volume increases, consistent with neural over-proliferation. However, little is known about alterations in white matter microstructure in NF1. We performed diffusion tensor imaging (DTI) analyses using tract-based spatial statistics (TBSS) in 14 young adult NF1 patients and 12 healthy controls. We also examined brain volumetric measures in the same subjects. Consistent with prior studies, we found significantly increased overall gray and white matter volume in NF1 patients. Relative to healthy controls, NF1 patients showed widespread reductions in white matter integrity across the entire brain as reflected by decreased fractional anisotropy (FA) and significantly increased absolute diffusion (ADC). When radial and axial diffusion were examined we found pronounced differences in radial diffusion in NF1 patients, indicative of either decreased myelination or increased space between axons. Secondary analyses revealed that FA and radial diffusion effects were of greatest magnitude in the frontal lobe. Such alterations of white matter tracts connecting frontal regions could contribute to the observed cognitive deficits. Furthermore, although the cellular basis of these white matter microstructural alterations remains to be determined, our findings of disproportionately increased radial diffusion against a background of increased white matter volume suggest the novel hypothesis that one potential alteration contributing to increased cortical white matter in NF1 may be looser packing of axons, with or without myelination changes. Further, this indicates that axial and radial diffusivity can uniquely contribute as markers of NF1-associated brain pathology in conjunction with the typically investigated measures.

Karlsgodt, Katherine H.; Rosser, Tena; Lutkenhoff, Evan S.; Cannon, Tyrone D.; Silva, Alcino; Bearden, Carrie E.

2012-01-01

54

White matter loss in healthy ageing: A postmortem analysis  

Microsoft Academic Search

Age-related brain changes are widely documented. Because of differences in measurement methods and case selection, the reported effects of age on regional grey and white matter brain volumes, however, are much more pronounced and widespread in neuroimaging than in postmortem studies. Consequently, the magnitude of the effect that is specific to chronological age remains unresolved. We present postmortem volume measurements

O. Piguet; K. L. Double; J. J. Kril; J. Harasty; V. Macdonald; D. A. McRitchie; G. M. Halliday

2009-01-01

55

Whole Brain and Regional Hyperintense White Matter Volume and Blood Pressure: Overlap of Genetic Loci produced by Bivariate, Whole-Genome Linkage Analyses  

PubMed Central

Background and Purpose The volume of T2-hyperintense white matter (HWM) is an important neuroimaging marker of cerebral integrity, with a demonstrated high heritability. Pathophysiology studies have shown that the regional, ependymal and subcortical, HWM lesions are associated with elevated arterial pulse pressure (PP) and arterial blood pressure (BP), respectively. We performed bivariate, whole-genome linkage analyses for HWM volumes and BP-measurements to identify chromosomal regions that contribute jointly to both traits in a population of healthy Mexican Americans. Our aims were to localize novel quantitative trait loci (QTLs) acting pleiotropically upon these phenotypes and to replicate previous genetic findings on WB-HWM volume and BP measurements. Methods BP measurements and volumes of whole-brain (WB), subcortical and ependymal HWM lesions, measured from high-resolution (1mm3) 3D-FLAIR images, served as focal quantitative phenotypes. Data were collected from 357 (218 females; mean age=47.9±13.2years) members of large extended families who participated in the San Antonio Family Heart Study. Results Bivariate genome-wide linkage analyses localized a significant QTL influencing WB-and regional (ependymal) HWM volumes and PP and systolic BP, to chromosomal location 1q24 between markers D1S196–D1S1619. Several other chromosomal regions (1q42, 10q24–q26 and 15q26) exhibited suggestive linkages. The results of the post-hoc analyses that excluded 55 subjects taking anti-hypertensive medication showed no substantive differences from the results obtained in the full cohort. Conclusion This study confirms several previously observed QTLs influencing BP and cerebral integrity and identifies a novel significant QTL at chromosome 1q24. The genetic results strongly support a role for pleiotropically-acting genes jointly influencing BP and cerebral WM integrity.

Kochunov, P.; Glahn, D.; Lancaster, J.; Winkler, A.; Kent, JW; Olvera, RL; Cole, SA; Dyer, TD; Almasy, L; Duggirala, R.; Fox, PT; Blangero, J

2011-01-01

56

SCIENCE MATTERS (White) Hooded Sweatshirt (Size: Small)  

NSDL National Science Digital Library

White, heavy duty 9.3 oz. 50/50 blend, double-lined hood and pockets. Sweatshirt is printed with Science Matters logo on front and NSTA logo on back. Available in Adult sizes: Small, Medium, Large, X Large, XX Large.

1900-01-01

57

SCIENCE MATTERS (White) Hooded Sweatshirt (Size: Large)  

NSDL National Science Digital Library

White, heavy duty 9.3 oz. 50/50 blend, double-lined hood and pockets. Sweatshirt is printed with Science Matters logo on front and NSTA logo on back. Available in Adult sizes: Small, Medium, Large, X Large, XX Large.

1900-01-01

58

SCIENCE MATTERS (White) Hooded Sweatshirt (Size: Medium)  

NSDL National Science Digital Library

White, heavy duty 9.3 oz. 50/50 blend, double-lined hood and pockets. Sweatshirt is printed with Science Matters logo on front and NSTA logo on back. Available in Adult sizes: Small, Medium, Large, X Large, XX Large.

1900-01-01

59

White matter connectivity of human hypothalamus  

Microsoft Academic Search

The macroscopic extrinsic white matter connectivity and the internal structure of the hypothalamus are still incompletely defined in humans. We investigated whether in-vivo diffusion tensor imaging tractography provides evidence of systematization according to hypothalamic compartmentalization. Six defined hypothalamic macroscopic compartments, preoptic, supraoptic, anteroventral, anterodorsal, lateral and posterior, were probed, within the right and left hemispheres of 14 subjects. Important new

Jean-Jacques Lemaire; Andrew J. Frew; David McArthur; Alessandra A. Gorgulho; Jeffry R. Alger; Noriko Salomon; Clive Chen; Eric J. Behnke; Antonio A. F. De Salles

2011-01-01

60

White matter abnormalities in congenital muscular dystrophy  

Microsoft Academic Search

Central nervous system (CNS) characteristics were examined in seventeen patients with autosomal recessive classic or “pure” congenital muscular dystrophy (CMD). In three patients, neuroradiological examination (CT\\/MRI) indicated hypodense white matter areas. Two out of these three patients had epilepsy (seizures and epileptic discharges on their EEG). Only two of the remaining patients had epileptic EEG discharges, but without clinical seizures.

Q. H. Leyten; F. J. M. Gabreëls; W. O. Renier; B. G. M. van Engelen; H. J. ter Laak; R. C. A. Sengers; H. O. M. Thijssen

1995-01-01

61

White matter alterations associated with chromosomal disorders.  

PubMed

White matter alterations in chromosomal disorders have been reported mainly in 18q-syndrome. Our aim was to evaluate white matter alterations in patients with chromosomal abnormalities detected through conventional cytogenetic techniques. Forty-four patients with chromosomal abnormalities, excluding trisomy 21, were diagnosed in our hospital between May 1999 and December 2002 (24 males, 20 females; mean age 6 years 4 months [SD 3 years 2 months], range 0 to 18 years). Of the 44 patients, 14 had brain magnetic resonance imaging (12 males, 2 females; mean age 4 years 2 months [SD 4 years 4 months]; five with sex chromosomal disorders [SCD] and nine with autosomal chromosomal disorders [ACD]). Of these 14 patients, eight (four with SCD and four with ACD) had abnormal white matter findings of similar patterns. These patients had pseudonodular, subcortical, and periventricular white matter high signal intensity images in T2, and fluid-attenuated inversion recovery sequences that were isolated or confluent. The images did not correlate with the neurological clinical state. Given that eight of the 14 patients showed these lesions, their prevalence in different chromosomal abnormalities appears to be high, even though they have not been well reported in the literature. To our knowledge, these alterations have never been described in SCD. We concluded that unknown factors related to the myelination processes may be localized in different chromosomes. PMID:14995083

García-Cazorla, Angels; Sans, Anna; Baquero, Miguel; García-Bargo, María Dolores; Arellano, Montse; Poo, Pilar; Gean, Esther; Campistol, Jaume

2004-03-01

62

White matter integrity, substance use, and risk taking in adolescence.  

PubMed

White matter development is important for efficient communication between brain regions, higher order cognitive functioning, and complex behaviors. Adolescents have a higher propensity for engaging in risky behaviors, yet few studies have explored associations between white matter integrity and risk taking directly. Altered white matter integrity in mid-adolescence was hypothesized to predict subsequent risk taking behaviors 1.5 years later. Adolescent substance users (predominantly alcohol and marijuana, n = 47) and demographically similar nonusers (n = 49) received diffusion tensor imaging at baseline (ages 16-19), and risk taking measures at both baseline and an 18-month follow-up (i.e., at ages 17-20). Brain regions of interest were the fornix, superior corona radiata, superior longitudinal fasciculus, and superior fronto-occipital fasciculus. In substance-using youth (n = 47), lower white matter integrity at baseline in the fornix and superior corona radiata predicted follow-up substance use (?R2 = 10-12%, ps < .01), and baseline fornix integrity predicted follow-up delinquent behaviors (?R2 = 10%, p < .01) 1.5 years later. Poorer fronto-limbic white matter integrity was linked to a greater propensity for future risk taking behaviors among youth who initiated heavy substance use by mid-adolescence. Most notable were relationships between projection and limbic-system fibers and future substance-use frequency. Subcortical white matter coherence, along with an imbalance between the maturation levels in cognitive control and reward systems, may disadvantage the resistance to engage in risk taking behaviors during adolescence. PMID:22564204

Jacobus, Joanna; Thayer, Rachel E; Trim, Ryan S; Bava, Sunita; Frank, Lawrence R; Tapert, Susan F

2012-05-07

63

White matter abnormalities and animal models examining a putative role of altered white matter in schizophrenia.  

PubMed

Schizophrenia is a severe mental disorder affecting about 1% of the population worldwide. Although the dopamine (DA) hypothesis is still keeping a dominant position in schizophrenia research, new advances have been emerging in recent years, which suggest the implication of white matter abnormalities in schizophrenia. In this paper, we will briefly review some of recent human studies showing white matter abnormalities in schizophrenic brains and altered oligodendrocyte-(OL-) and myelin-related genes in patients with schizophrenia and will consider abnormal behaviors reported in patients with white matter diseases. Following these, we will selectively introduce some animal models examining a putative role of white matter abnormalities in schizophrenia. The emphasis will be put on the cuprizone (CPZ) model. CPZ-fed mice show demyelination and OLs loss, display schizophrenia-related behaviors, and have higher DA levels in the prefrontal cortex. These features suggest that the CPZ model is a novel animal model of schizophrenia. PMID:22937274

Xu, Haiyun; Li, Xin-Min

2011-08-11

64

Abnormal white matter microstructure in children with sensory processing disorders?  

PubMed Central

Sensory processing disorders (SPD) affect 5–16% of school-aged children and can cause long-term deficits in intellectual and social development. Current theories of SPD implicate primary sensory cortical areas and higher-order multisensory integration (MSI) cortical regions. We investigate the role of white matter microstructural abnormalities in SPD using diffusion tensor imaging (DTI). DTI was acquired in 16 boys, 8–11 years old, with SPD and 24 age-, gender-, handedness- and IQ-matched neurotypical controls. Behavior was characterized using a parent report sensory behavior measure, the Sensory Profile. Fractional anisotropy (FA), mean diffusivity (MD) and radial diffusivity (RD) were calculated. Tract-based spatial statistics were used to detect significant group differences in white matter integrity and to determine if microstructural parameters were significantly correlated with behavioral measures. Significant decreases in FA and increases in MD and RD were found in the SPD cohort compared to controls, primarily involving posterior white matter including the posterior corpus callosum, posterior corona radiata and posterior thalamic radiations. Strong positive correlations were observed between FA of these posterior tracts and auditory, multisensory, and inattention scores (r = 0.51–0.78; p < 0.001) with strong negative correlations between RD and multisensory and inattention scores (r = ? 0.61–0.71; p < 0.001). To our knowledge, this is the first study to demonstrate reduced white matter microstructural integrity in children with SPD. We find that the disrupted white matter microstructure predominantly involves posterior cerebral tracts and correlates strongly with atypical unimodal and multisensory integration behavior. These findings suggest abnormal white matter as a biological basis for SPD and may also distinguish SPD from overlapping clinical conditions such as autism and attention deficit hyperactivity disorder.

Owen, Julia P.; Marco, Elysa J.; Desai, Shivani; Fourie, Emily; Harris, Julia; Hill, Susanna S.; Arnett, Anne B.; Mukherjee, Pratik

2013-01-01

65

White matter hyperintensities and chronicity of depression  

Microsoft Academic Search

Objective: White matter hyperintensities (WMHs) on T2-weighted magnetic resonance imaging (MRI) of the brain are associated with advanced age and late-life depression. Most investigations predominately found these lesions in frontal lobe and basal ganglia supporting the hypothesis of a fronto-striatal dysfunction in depression. A prospective study was undertaken to investigate the asso- ciation between extent of WMHs and clinical outcome

Angela Heiden; Joachim Kettenbach; Peter Fischer; Bettina Schein; Ahmed Ba-Ssalamah; Richard Frey; Mohammad Mehdi Naderi; Talin Gulesserian; Daniela Schmid; Siegfried Trattnig; Herwig Imhof; Siegfried Kasper

66

Abnormal gray and white matter volume in delusional infestation.  

PubMed

Little is known about the neural basis of delusional infestation (DI), the delusional belief to be infested with pathogens. Case series and the response to anti-dopaminergic medication indicate disruptions in dopaminergic neurotransmission in the striatum (caudate, putamen), but did not allow for population-based inference. Here, we report the first whole-brain structural neuroimaging study to investigate gray and white matter abnormalities in DI compared to controls. In this study, we used structural magnetic resonance imaging and voxel-based morphometry to investigate gray and white matter volume in 16 DI patients and 16 matched healthy controls. Lower gray matter volume in DI patients compared to controls was found in left medial, lateral and right superior frontal cortices, left anterior cingulate cortex, bilateral insula, left thalamus, right striatal areas and in lateral and medial temporal cortical regions (p<0.05, cluster-corrected). Higher white matter volume in DI patients compared to controls was found in right middle cingulate, left frontal opercular and bilateral striatal regions (p<0.05, cluster-corrected). This study shows that structural changes in prefrontal, temporal, insular, cingulate and striatal brain regions are associated with DI, supporting a neurobiological model of disrupted prefrontal control over somato-sensory representations. PMID:23791615

Wolf, Robert Christian; Huber, Markus; Depping, Malte Sebastian; Thomann, Philipp Arthur; Karner, Martin; Lepping, Peter; Freudenmann, Roland W

2013-06-19

67

White matter damage in preterm newborns--an epidemiologic perspective.  

PubMed

Prior to 1980, white matter abnormalities of the preterm newborn were known exclusively as pathological entities, but now cranial ultrasonography can image white matter abnormalities in life. Ultrasonographic white matter echodensities and echolucencies in low birthweight babies predict later handicap (especially cerebral palsy) more accurately than any other antecedent. With the increased availability of high resolution cranial ultrasonography and the improved skill in obtaining and reading cranial ultrasonograms, rapid gains can be expected in our understanding of white matter disorders. These advances are likely to be made in the diagnosis and classification of white matter disorders and in their epidemiologic and prognostic features, topics explored in this review. PMID:2265595

Leviton, A; Paneth, N

1990-10-01

68

Connecting white matter injury and thalamic atrophy in clinically isolated syndromes.  

PubMed

Previous studies suggest that thalamic degeneration is prominent in multiple sclerosis (MS) and even in pre-MS patients presenting with a clinically isolated syndrome (CIS). However, the relationships between white matter lesions and deep grey matter loss are not well understood. We analyzed the association between white matter lesions and the thalami in CIS patients to determine if connectivity is an important determinant. We studied 24 CIS patients and 18 normal controls with anatomical and diffusion tensor (DTI) MRI images. DTI fiber tracking was used to create probabilistic templates of the thalamocortical white matter and to define white matter connecting lesions and thalami. DTI metrics in the lesions and normal-appearing white matter (NAWM) regions were compared between CIS and controls, and correlated with thalamic volume changes estimated by voxel-based morphometry. There was 10 times higher density of lesions in thalamocortical compared to other brain white matter. Increased diffusivities and decreased fractional anisotropies were measured in the thalamocortical NAWM of CIS patients compared to controls. A step-wise regression analysis demonstrated that thalamocortical lesion volume and the mean diffusivity in track regions connecting lesion and thalami were significantly correlated with thalamic volumes in patients (Rsq=0.66, p<0.001), a finding not observed in regions outside the thalamocortical white matter. These results provide compelling evidence for a direct relationship between white matter lesions and thalamic atrophy in CIS patients. PMID:19394969

Henry, Roland G; Shieh, Mason; Amirbekian, Bagrat; Chung, SungWon; Okuda, Darin T; Pelletier, Daniel

2009-04-23

69

White matter abnormalities in dystonia normalize after botulinum toxin treatment  

PubMed Central

The pathophysiology of dystonia is still poorly understood. We used diffusion tensor imaging to screen for white matter abnormalities in regions between the basal ganglia and the thalamus in cervical and hand dystonia patients. All patients exhibited an abnormal hemispheric asymmetry in a focal region between the pallidum and the thalamus. This asymmetry was absent 4 weeks after the same patients were treated with intramuscular botulinum toxin injections. These findings represent a new systems-level abnormality in dystonia, which may lead to new insights about the pathophysiology of movement disorders. More generally, these findings demonstrate central nervous system changes following peripheral reductions in muscle activity. This raises the possibility that we have observed activity-dependent white matter plasticity in the adult human brain.

Blood, Anne J.; Tuch, David S.; Makris, Nikos; Makhlouf, Miriam L.; Sudarsky, Lewis R.; Sharma, Nutan

2011-01-01

70

Magnetization transfer changes of grey and white matter in Parkinson's disease  

Microsoft Academic Search

Since the attempt to evidence structural brain damage in Parkinson's disease (PD) by conventional magnetic resonance imaging (MRI) is usually disappointing, we have investigated whether the magnetization transfer ratio (MTR) can reflect changes in grey and white matter of PD patients. MTR was quantified in 44 regions of interest (ROIs) in both grey and white matter of 11 non-demented PD

N. Tambasco; G. P. Pelliccioli; P. Chiarini; G. E. Montanari; F. Leone; M. L. Mancini; M. Paciaroni; V. Gallai

2003-01-01

71

Gray matter and white matter abnormalities in online game addiction.  

PubMed

Online game addiction (OGA) has attracted greater attention as a serious public mental health issue. However, there are only a few brain magnetic resonance imaging studies on brain structure about OGA. In the current study, we used voxel-based morphometry (VBM) analysis and tract-based spatial statistics (TBSS) to investigate the microstructural changes in OGA and assessed the relationship between these morphology changes and the Young's Internet Addiction Scale (YIAS) scores within the OGA group. Compared with healthy subjects, OGA individuals showed significant gray matter atrophy in the right orbitofrontal cortex, bilateral insula, and right supplementary motor area. According to TBSS analysis, OGA subjects had significantly reduced FA in the right genu of corpus callosum, bilateral frontal lobe white matter, and right external capsule. Gray matter volumes (GMV) of the right orbitofrontal cortex, bilateral insula and FA values of the right external capsule were significantly positively correlated with the YIAS scores in the OGA subjects. Our findings suggested that microstructure abnormalities of gray and white matter were present in OGA subjects. This finding may provide more insights into the understanding of the underlying neural mechanisms of OGA. PMID:23480966

Weng, Chuan-Bo; Qian, Ruo-Bing; Fu, Xian-Ming; Lin, Bin; Han, Xiao-Peng; Niu, Chao-Shi; Wang, Ye-Han

2013-03-06

72

Associations between white matter microstructure and infants' working memory.  

PubMed

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

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

2012-09-16

73

Diffusion features of white matter in tuberous sclerosis with tractography.  

PubMed

Normal-appearing white matter has been shown via diffusion tensor imaging to be affected in tuberous sclerosis complex. Under the hypothesis that some systems might be differentially affected, including the visual pathways and systems of social cognition, diffusion properties of various regions of white matter were compared. For 10 patients and 6 age-matched control subjects, 3 T magnetic resonance imaging was assessed using diffusion tensor imaging obtained in 35 directions. Three-dimensional volumes corresponding to the geniculocalcarine tracts were extracted via tractography, and two-dimensional regions of interest were used to sample other regions. Regression analysis indicated lower fractional anisotropy in the splenium of corpus callosum and geniculocalcarine tracts in tuberous sclerosis complex group, as well as lower axial diffusivity in the internal capsule, superior temporal gyrus, and geniculocalcarine tracts. Mean and radial diffusivity of the splenium of corpus callosum were higher in the tuberous sclerosis complex group. The differences in diffusion properties of white matter between tuberous sclerosis complex patients and control subjects suggest disorganized and structurally compromised axons with poor myelination. The visual and social cognition systems appear to be differentially involved, which might in part explain the behavioral and cognitive characteristics of the tuberous sclerosis complex population. PMID:20117745

Krishnan, Michelle L; Commowick, Olivier; Jeste, Shafali S; Weisenfeld, Neil; Hans, Arne; Gregas, Matthew C; Sahin, Mustafa; Warfield, Simon K

2010-02-01

74

Automatic identification of gray matter structures from MRI to improve the segmentation of white matter lesions  

Microsoft Academic Search

The segmentation of MRI scans of patients with white matter lesions (WML) is difficult because the MRI characteristics of white matter lesions are simi- lar to those of grey matter. Intensity based statistical classification techniques misclassify some WML as grey matter and some grey matter as WML. We developed a fast elastic matching algorithm that warps a reference data set

Simon Warfield; Joachim Dengler; Joachim Zaers; Charles R. G. Guttmann; William M. Wells; Gil J. Ettinger; John Hiller; Ron Kikinis

1995-01-01

75

Solubility of Volatile Anesthetics in Bovine White Matter, Cortical Gray Matter, Thalamus, Hippocampus, and Hypothalamic Area  

Microsoft Academic Search

Although known for whole brain, values are lacking for solubilities of modern volatile anesthetics in spe- cific brain regions. Some regions should differ from others(e.g.,graymatterversuswhitematter)because they differ in lipid content and because potent in- haled anesthetics are lipophilic. In the present report, we examined this issue in bovine brain, finding that white matter\\/gas partition coefficients are 1.6 (des- flurane) to

Mireille A. Neumann; Edmond I Eger II; Richard B. Weiskopf

2005-01-01

76

White matter structure changes as adults learn a second language.  

PubMed

Traditional models hold that the plastic reorganization of brain structures occurs mainly during childhood and adolescence, leaving adults with limited means to learn new knowledge and skills. Research within the last decade has begun to overturn this belief, documenting changes in the brain's gray and white matter as healthy adults learn simple motor and cognitive skills [Lövdén, M., Bodammer, N. C., Kühn, S., Kaufmann, J., Schütze, H., Tempelmann, C., et al. Experience-dependent plasticity of white-matter microstructure extends into old age. Neuropsychologia, 48, 3878-3883, 2010; Taubert, M., Draganski, B., Anwander, A., Müller, K., Horstmann, A., Villringer, A., et al. Dynamic properties of human brain structure: Learning-related changes in cortical areas and associated fiber connections. The Journal of Neuroscience, 30, 11670-11677, 2010; Scholz, J., Klein, M. C., Behrens, T. E. J., & Johansen-Berg, H. Training induces changes in white-matter architecture. Nature Neuroscience, 12, 1370-1371, 2009; Draganski, B., Gaser, C., Busch, V., Schuirer, G., Bogdahn, U., & May, A. Changes in grey matter induced by training. Nature, 427, 311-312, 2004]. Although the significance of these changes is not fully understood, they reveal a brain that remains plastic well beyond early developmental periods. Here we investigate the role of adult structural plasticity in the complex, long-term learning process of foreign language acquisition. We collected monthly diffusion tensor imaging scans of 11 English speakers who took a 9-month intensive course in written and spoken Modern Standard Chinese as well as from 16 control participants who did not study a language. We show that white matter reorganizes progressively across multiple sites as adults study a new language. Language learners exhibited progressive changes in white matter tracts associated with traditional left hemisphere language areas and their right hemisphere analogs. Surprisingly, the most significant changes occurred in frontal lobe tracts crossing the genu of the corpus callosum-a region not generally included in current neural models of language processing. These results indicate that plasticity of white matter plays an important role in adult language learning and additionally demonstrate the potential of longitudinal diffusion tensor imaging as a new tool to yield insights into cognitive processes. PMID:22571459

Schlegel, Alexander A; Rudelson, Justin J; Tse, Peter U

2012-05-09

77

The generation and validation of white matter connectivity importance maps  

PubMed Central

Both the size and location of injury in the brain influences the type and severity of cognitive or sensorimotor dysfunction. However, even with advances in MR imaging and analysis, the correspondence between lesion location and clinical deficit remains poorly understood. Here, structural and diffusion images from 14 healthy subjects are used to create spatially unbiased white matter connectivity importance maps that quantify the amount of disruption to the overall brain network that would be incurred if that region were compromised. Some regions in the white matter that were identified as highly important by such maps have been implicated in strategic infarct dementia and linked to various attention tasks in previous studies. Validation of the maps is performed by investigating the correlations of the importance maps’ predicted cognitive deficits in a group of 15 traumatic brain injury patients with their cognitive test scores measuring attention and memory. While no correlation was found between amount of white matter injury and cognitive test scores, significant correlations (r > 0.68, p < 0.006) were found when including location information contained in the importance maps. These tools could be used by physicians to improve surgical planning, diagnosis, and assessment of disease severity in a variety of pathologies like multiple sclerosis, trauma, and stroke.

Kuceyeski, Amy; Maruta, Jun; Niogi, Sumit N.; Ghajar, Jamshid; Raj, Ashish

2011-01-01

78

Computational representation of white matter fiber orientations.  

PubMed

We present a new methodology based on directional data clustering to represent white matter fiber orientations in magnetic resonance analyses for high angular resolution diffusion imaging. A probabilistic methodology is proposed for estimating intravoxel principal fiber directions, based on clustering directional data arising from orientation distribution function (ODF) profiles. ODF reconstructions are used to estimate intravoxel fiber directions using mixtures of von Mises-Fisher distributions. The method focuses on clustering data on the unit sphere, where complexity arises from representing ODF profiles as directional data. The proposed method is validated on synthetic simulations, as well as on a real data experiment. Based on experiments, we show that by clustering profile data using mixtures of von Mises-Fisher distributions it is possible to estimate multiple fiber configurations in a more robust manner than currently used approaches, without recourse to regularization or sharpening procedures. The method holds promise to support robust tractographic methodologies and to build realistic models of white matter tracts in the human brain. PMID:24023538

Ferreira da Silva, Adelino R

2013-08-20

79

Sex Differences in White Matter Alterations Accompanying Obstructive Sleep Apnea  

PubMed Central

Study Objectives: Females with obstructive sleep apnea (OSA) show different psychological and physiological symptoms from males, which may be associated with sex-related variations in neural injury occurring with the disorder. To determine whether male- or female-specific brain injury is present in OSA, we assessed influences of sex on white matter changes in the condition. Design: Two-group factorial. Setting: University medical center. Patients or Participants: 80 subjects total, with newly diagnosed, untreated OSA groups of 10 female (age mean ± SE: 52.6 ± 2.4 years, AHI 22.5 ± 4.1 events/h) and 20 male (age 48.9 ± 1.7, AHI 25.5 ± 2.9) patients, and 20 female (age 50.3 ± 1.7) and 30 male (age 49.2 ± 1.4) healthy control subjects. Interventions: None. Measurements and Results: Brain fiber integrity was assessed with fractional anisotropy (FA), a diffusion tensor imaging-derived measure. Sleep quality, daytime sleepiness, depression, and anxiety were assessed with questionnaires. We identified regions of differing injury in male versus female OSA patients by assessing brain regions with significant interaction effects of OSA and sex on FA. Areas of sex-specific, OSA-related FA reductions appeared in females relative to males, including in the bilateral cingulum bundle adjacent to the mid hippocampus, right stria terminalis near the amygdala, prefrontal and posterior-parietal white matter, corpus callosum, and left superior cerebellar peduncle. Females with OSA showed higher daytime sleepiness, anxiety and depression levels, and reduced sleep quality. Conclusions: Sex differences in white matter structural integrity appeared in OSA patients, with females more affected than males. These female-specific structural changes may contribute to or derive from neuropsychological and physiological symptom differences between sexes. Citation: Macey PM; Kumar R; Yan-Go FL; Woo MA; Harper RM. Sex differences in white matter alterations accompanying obstructive sleep apnea. SLEEP 2012;35(12):1603-1613.

Macey, Paul M.; Kumar, Rajesh; Yan-Go, Frisca L.; Woo, Mary A.; Harper, Ronald M.

2012-01-01

80

Oxidative stress, brain white matter damage and intrauterine asphyxia in fetal lambs.  

PubMed

In order to examine the role of oxidative stress in asphyxia-induced perinatal brain damage, near-term fetal lambs were subjected to umbilical cord occlusion for approximately 60min until fetal arterial pH diminished to less than 6.9 and base excess to less than -20 meq/l. The levels of superoxide, hydrogen peroxide, glutathione (GSH) and thiobarbiturate-reactive substances (TBARS) within brain grey and white matter were determined at 72h to correlate with morphological changes. Although the topography and extent of brain damage varied somewhat from case to case, ranging from focal infarction in grey or white matter to subtle and patchy alterations of white matter, the telencephalic white matter appeared to bear the brunt of damage as compared to other regions. The parietal white matter, in particular was often the seat of early pathological changes that could be seen in isolation. These white matter changes were accompanied by significant increases in hydrogen peroxide and TBARS levels as compared to those in grey matter. In another set of experiments, 8 different brain regions were assayed for TBARS, GSH and superoxide dismutase (SOD). A highly significant rise in the levels of TBARS was again noted in the parietal and frontal white matter. SOD levels were higher in the frontal and parietal white matter, basal ganglia and cerebellum. Cerebral cortical and hippocampal neurons were relatively unaffected until accompanied by more severe damage to grey and white matter at other sites. These results suggest that the developing telencephalic white matter appears to be most vulnerable to the effects of intrauterine fetal asphyxia and that oxidative stress may be a major contributing factor in the pathogenesis of perinatal hypoxic-ischemic encephalopathy. PMID:10219955

Ikeda, T; Choi, B H; Yee, S; Murata, Y; Quilligan, E J

1999-02-01

81

Infrared spectroscopic characterization of human white matter, grey matter, and multiple sclerosis lesions  

Microsoft Academic Search

FT-IR spectroscopy has been used to characterize white matter, grey matter, and multiple sclerosis (MS) plaques from human central nervous system (CNS) tissue. Discrimination among these three tissue types is possible due to variations in composition. Spectra of white matter exhibit strong lipid absorptions. In contrast, spectra of grey matter reveal a reduced lipid contribution and a significant absorption from

Lin-P'ing Choo; Michael Jackson; William C. Halliday; Henry H. Mantsch

1994-01-01

82

Regional grey and white matter volumetric changes in myalgic encephalomyelitis (chronic fatigue syndrome): a voxel-based morphometry 3 T MRI study  

PubMed Central

Objective It is not established whether myalgic encephalomyelitis/chronic fatigue syndrome (CFS) is associated with structural brain changes. The aim of this study was to investigate this by conducting the largest voxel-based morphometry study to date in CFS. Methods High-resolution structural 3 T cerebral MRI scanning was carried out in 26 patients with CFS and 26 age- and gender-matched healthy volunteers. Voxel-wise generalised linear modelling was applied to the processed MR data using permutation-based non-parametric testing, forming clusters at t>2.3 and testing clusters for significance at p<0.05, corrected for multiple comparisons across space. Results Significant voxels (p<0.05, corrected for multiple comparisons) depicting reduced grey matter volume in the CFS group were noted in the occipital lobes (right and left occipital poles; left lateral occipital cortex, superior division; and left supracalcrine cortex), the right angular gyrus and the posterior division of the left parahippocampal gyrus. Significant voxels (p<0.05, corrected for multiple comparisons) depicting reduced white matter volume in the CFS group were also noted in the left occipital lobe. Conclusion These data support the hypothesis that significant neuroanatomical changes occur in CFS, and are consistent with the complaint of impaired memory that is common in this illness; they also suggest that subtle abnormalities in visual processing, and discrepancies between intended actions and consequent movements, may occur in CFS.

Puri, B K; Jakeman, P M; Agour, M; Gunatilake, K D R; Fernando, K A C; Gurusinghe, A I; Treasaden, I H; Waldman, A D; Gishen, P

2012-01-01

83

White matter integrity and cortical metabolic associations in aging and dementia  

PubMed Central

Background Studies show white matter hyperintensities, regardless of location, primarily affect frontal lobe metabolism and function. This report investigates how regional white matter integrity (measured as fractional anisotropy (FA)) relates to brain metabolism in order to unravel the complex relationship between white matter change and brain metabolism. Objective To elucidate the relationship between white matter integrity and gray matter metabolism using diffusion tensor imaging (DTI) and fluorodeoxyglucose-positron emission tomography (FDG-PET) in a cohort of 16 subjects ranging from normal to demented (age>55). Methods Cross-sectional regression analyses using mean FA values from white matter regions underlying the medial prefrontal, inferior-lateral prefrontal, parietal association, and posterior temporal areas and corpus callosum were regressed with glucose metabolism (PET) using SPM2 (p < 0.005, voxel cluster > 100). Regional cerebral glucose metabolism was the primary outcome measure, with our major hypotheses being those hypometabolic cortical regions affected by Alzheimer’s disease would correlate with lower FA of associated tracks. Results Our data show inter-regional positive correlations between FA and gray matter metabolism for the prefrontal cortex, temporal and parietal regions. Our results suggest left prefrontal FA is associated with left temporal and parietal metabolism. Further, left posterior temporal FA correlated with left prefrontal metabolism. Finally, bilateral parietal FA correlated with bilateral temporal metabolism. Conclusions These regions are associated with the cognitive processes affected in AD and Cerebrovascular Disease, suggesting a link with white matter degeneration and gray matter hypometabolism. Therefore cortical function and white matter degeneration are related in aging and dementia.

Kuczynski, B.; Targan, E.; Madison, C.; Weiner, M.; Zhang, Y.; Reed, B.; Chui, HC.; Jagust, W.

2009-01-01

84

White Matter Abnormalities in Major Depression: A Tract-Based Spatial Statistics and Rumination Study  

PubMed Central

Increasing evidence indicates that major depressive disorder (MDD) is usually accompanied by altered white matter in the prefrontal cortex, the parietal lobe and the limbic system. As a behavioral abnormity of MDD, rumination has been believed to be a substantial indicator of the mental state of the depressive state. So far, however, no report that we are aware of has evaluated the relationship between white matter alterations and the ruminative state. In this study, we first explored the altered white matter using a tract-based spatial statistics (TBSS) method based on diffusion tensor imaging of 19 healthy and 16 depressive subjects. We then investigated correlations between the altered white matter microstructure in the identified altered regions and the severity of ruminations measured by the ruminative response scale. Our results demonstrated altered white matter microstructure in circuits connecting the prefrontal lobe, the parietal lobe and the limbic system (p<0.005, uncorrected), findings which support previous research. More importantly, the result also indicated that a greater alteration in the white matter is associated with a more ruminative state (p<0.05, Bonferroni corrected). The detected abnormalities in the white matter should be interpreted cautiously because of the small sample size in this study. This finding supports the psychometric significance of white matter deficits in MDD.

Lv, Xueyu; Zhou, Yuan; Hong, Yang; Li, Tao; Tong, Haibing; Wang, Xiaoling; Wang, Weidong; Jiang, Tianzi

2012-01-01

85

White matter in learning, cognition and psychiatric disorders  

PubMed Central

White matter is the brain region underlying the gray matter cortex, composed of neuronal fibers coated with electrical insulation called myelin. Previously of interest in demyelinating diseases such as multiple sclerosis, myelin is attracting new interest as an unexpected contributor to a wide range of psychiatric disorders, including depression and schizophrenia. This is stimulating research into myelin involvement in normal cognitive function, learning and IQ. Myelination continues for decades in the human brain; it is modifiable by experience, and it affects information processing by regulating the velocity and synchrony of impulse conduction between distant cortical regions. Cell-culture studies have identified molecular mechanisms regulating myelination by electrical activity, and myelin also limits the critical period for learning through inhibitory proteins that suppress axon sprouting and synaptogenesis.

Fields, R. Douglas

2008-01-01

86

Altering cortical connectivity: Remediation-induced changes in the white matter of poor readers  

PubMed Central

SUMMARY Neuroimaging studies using diffusion tensor imaging (DTI) have revealed regions of cerebral white matter with decreased microstructural organization (lower fractional anisotropy or FA) among poor readers. We examined whether 100 hours of intensive remedial instruction affected the white matter of 8–10-year-old poor readers. Prior to instruction, poor readers had significantly lower FA than good readers in a region of the left anterior centrum semiovale. The instruction resulted in a change in white matter (significantly increased FA), and in the very same region. The FA increase was correlated with a decrease in radial diffusivity (but not with a change in axial diffusivity), suggesting that myelination had increased. Furthermore, the FA increase was correlated with improvement in phonological decoding ability, clarifying the cognitive locus of the effect. The results demonstrate for the first time the capability of a behavioral intervention to bring about a positive change in cortico-cortical white matter tracts.

Keller, Timothy A.; Just, Marcel Adam

2009-01-01

87

A Method for Clustering White Matter Fiber Tracts  

PubMed Central

BACKGROUND/PURPOSE Despite its potential for visualizing white matter fiber tracts in vivo, diffusion tensor tractography has found only limited applications in clinical research in which specific anatomic connections between distant regions need to be evaluated. We introduce a robust method for fiber clustering that guides the separation of anatomically distinct fiber tracts and enables further estimation of anatomic connectivity between distant brain regions. METHODS Line scanning diffusion tensor images (LSDTI) were acquired on a 1.5T magnet. Regions of interest for several anatomically distinct fiber tracts were manually drawn; then, white matter tractography was performed by using the Runge-Kutta method to interpolate paths (fiber traces) following the major directions of diffusion, in which traces were seeded only within the defined regions of interest. Next, a fully automatic procedure was applied to fiber traces, grouping them according to a pairwise similarity function that takes into account the shapes of the fibers and their spatial locations. RESULTS We demonstrated the ability of the clustering algorithm to separate several fiber tracts which are otherwise difficult to define (left and right fornix, uncinate fasciculus and inferior occipitofrontal fasciculus, and corpus callosum fibers). CONCLUSION This method successfully delineates fiber tracts that can be further analyzed for clinical research purposes. Hypotheses regarding specific fiber connections and their abnormalities in various neuropsychiatric disorders can now be tested.

O'Donnell, L.J.; Kubicki, M.; Shenton, M.E.; Dreusicke, M.H.; Grimson, W.E.L.; Westin, C.F.

2009-01-01

88

Inflammation in White Matter: Clinical and Pathophysiological Aspects  

ERIC Educational Resources Information Center

|While the central nervous system (CNS) is generally thought of as an immunopriviledged site, immune-mediated CNS white matter damage can occur in both the perinatal period and in adults, and can result in severe and persistent neurological deficits. Periventricular leukomalacia (PVL) is an inflammatory white matter disease of premature infants…

Pleasure, David; Soulika, Athena; Singh, Sunit K.; Gallo, Vittorio; Bannerman, Peter

2006-01-01

89

Inflammation in White Matter: Clinical and Pathophysiological Aspects  

ERIC Educational Resources Information Center

While the central nervous system (CNS) is generally thought of as an immunopriviledged site, immune-mediated CNS white matter damage can occur in both the perinatal period and in adults, and can result in severe and persistent neurological deficits. Periventricular leukomalacia (PVL) is an inflammatory white matter disease of premature infants…

Pleasure, David; Soulika, Athena; Singh, Sunit K.; Gallo, Vittorio; Bannerman, Peter

2006-01-01

90

White Matter Development during Adolescence as Shown by Diffusion MRI  

ERIC Educational Resources Information Center

|Previous volumetric developmental MRI studies of the brain have shown white matter development continuing through adolescence and into adulthood. This review presents current findings regarding white matter development and organization from diffusion MRI studies. The general trend during adolescence (age 12-18 years) is towards increasing…

Schmithorst, Vincent J.; Yuan, Weihong

2010-01-01

91

Classification in DTI using shapes of white matter tracts  

Microsoft Academic Search

Diffusion tensor imaging (DTI) provides unique information about the underlying tissue structure of brain white matter in vivo, including both the geometry of fiber bundles as well as quantitative information about tissue properties as characterized by measures such as tensor orientation, anisotropy, and size. Our objective in this paper is to evaluate the utility of shape representations of white matter

Nagesh Adluru; Chris Hinrichs; Moo K. Chung; Jee-Eun Lee; Vikas Singh; Erin D. Bigler; Nicholas Lange; Janet E. Lainhart; Andrew L. Alexander

2009-01-01

92

Cognitive correlates of white matter growth and stress hormones in female squirrel monkey adults.  

PubMed

Neurobiological studies of stress and cognitive aging seldom consider white matter despite indications that complex brain processes depend on networks and white matter interconnections. Frontal and temporal lobe white matter volumes increase throughout midlife adulthood in humans, and this aspect of aging is thought to enhance distributed brain functions. Here, we examine spatial learning and memory, neuroendocrine responses to psychological stress, and regional volumes of gray and white matter determined by magnetic resonance imaging in 31 female squirrel monkeys between the ages of 5 and 17 years. This period of lifespan development corresponds to the years 18-60 in humans. Older adults responded to stress with greater increases in plasma levels of adrenocorticotropic hormone and modest reductions in glucocorticoid feedback sensitivity relative to young adults. Learning and memory did not differ with age during the initial cognitive test sessions, but older adults more often failed to inhibit the initial learned response after subsequent spatial reversals. Impaired cognitive response inhibition correlated with the expansion of white matter volume statistically controlling for age, stress hormones, gray matter, and CSF volumes. These results indicate that instead of enhancing cognitive control during midlife adulthood, white matter volume expansion contributes to aspects of cognitive decline. Cellular and molecular research combined with brain imaging is needed to determine the basis of white matter growth in adults, elucidate its functions during lifespan development, and provide potential new targets for therapies aimed at maintaining in humans cognitive vitality with aging. PMID:15071114

Lyons, David M; Yang, Chou; Eliez, Stephan; Reiss, Allan L; Schatzberg, Alan F

2004-04-01

93

Decreased white matter integrity in neuropsychologically defined mild cognitive impairment is independent of cortical thinning.  

PubMed

Improved understanding of the pattern of white matter changes in early and prodromal Alzheimer’s disease (AD) states such as mild cognitive impairment (MCI) is necessary to support earlier preclinical detection of AD, and debate remains whether white matter changes in MCI are secondary to gray matter changes. We applied neuropsychologically based MCI criteria to a sample of normally aging older adults; 32 participants met criteria for MCI and 81 participants were classified as normal control (NC) subjects. Whole-head high resolution T1 and diffusion tensor imaging scans were completed. Tract-Based Spatial Statistics was applied and a priori selected regions of interest were extracted. Hippocampal volume and cortical thickness averaged across regions with known vulnerability to AD were derived. Controlling for corticalthic kness, the MCI group showed decreased average fractional anisotropy (FA) and decreased FA in parietal white matter and in white matter underlying the entorhinal and posterior cingulate cortices relative to the NC group. Statistically controlling for cortical thickness, medial temporal FA was related to memory and parietal FA was related to executive functioning. These results provide further support for the potential role of white matter integrity as an early biomarker for individuals at risk for AD and highlight that changes in white matter may be independent of gray matter changes. PMID:23809097

Stricker, Nikki H; Salat, David H; Foley, Jessica M; Zink, Tyler A; Kellison, Ida L; McFarland, Craig P; Grande, Laura J; McGlinchey, Regina E; Milberg, William P; Leritz, Elizabeth C

2013-07-01

94

Neurocognitive Correlates of White Matter Quality in Adolescent Substance Users  

PubMed Central

Background Progressive myelination during adolescence implicates an increased vulnerability to neurotoxic substances and enduring neurocognitive consequences. This study examined the cognitive manifestations of altered white matter microstructure in chronic marijuana and alcohol-using (MJ+ALC) adolescents. Methods Thirty-six MJ+ALC adolescents (ages 16-19) and 36 demographically similar controls were evaluated with diffusion tensor imaging (Bava et al., 2009) and neurocognitive tests. Regions of group difference in fractional anisotropy (FA) and mean diffusivity (MD) were analyzed in relation to cognitive performance. Results In users, lower FA in temporal areas related to poorer performance on attention, working memory, and speeded processing tasks. Among regions where users had higher FA than controls, occipital FA was positively associated with working memory and complex visuomotor sequencing, whereas FA in anterior regions was negatively associated with verbal memory performance. Conclusions Findings suggest differential influences of white matter development on cognition in MJ+ALC using adolescents than in non-using peers. Neuroadaptation may reflect additive and subtractive responses to substance use that are complicated by competing maturational processes.

Bava, Sunita; Jacobus, Joanna; Mahmood, Omar; Yang, Tony T.; Tapert, Susan F.

2009-01-01

95

Pathophysiology of age-related cerebral white matter changes.  

PubMed

The pathogenesis of age-related cerebral white matter changes (WMC) is still a matter of investigation. Alterations of deep small vessels, such as arteriolosclerosis, are considered to play a central role in the development of WMC. Stenosis or occlusion of small vessels may cause sudden or more chronic ischemia resulting in small areas of necrosis (lacunar infarction) or diffuse alterations consistent with the definition of white matter incomplete infarct. Moreover, the arteriolosclerotic changes may cause loss of autoregulation in the deep white matter and consequent cerebral blood flow fluctuations in response to changes of systemic blood pressure. Both these types of mechanisms may be particularly harmful because the blood supply of the white matter is of the terminal type with scarce anastomoses. Other pathophysiological hypotheses on the origin of WMC have been raised, and they can probably be considered as complementary to the ischemic one. The small vessel alterations could lead to damage of the blood-brain barrier and chronic leakage of fluid and macromolecules in the white matter. The increased interstitial fluid concentration in abnormal white matter may be also a consequence of arterial hypertensive bouts. Genetically determined factors could play an important role in the development of WMC, and at least one disease (cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy - CADASIL) characterized by severe leukoencephalopathy exists with a determined genetic origin. It is possible that other genetic factors contribute, by interaction with conventional risk factors, to the development of white matter injury in nonfamilial cases. PMID:11901236

Pantoni, Leonardo

2002-01-01

96

Altered white matter microstructure in adolescent substance users.  

PubMed

Chronic marijuana use during adolescence is frequently comorbid with heavy alcohol consumption and associated with CNS alterations, yet the influence of early cannabis and alcohol use on microstructural white matter integrity is unclear. Building on evidence that cannabinoid receptors are present in myelin precursors and affect glial cell processing, and that excessive ethanol exposure is associated with persistently impaired myelination, we used diffusion tensor imaging (DTI) to characterize white matter integrity in heavy substance using and non-using adolescents. We evaluated 36 marijuana and alcohol-using (MJ+ALC) adolescents (ages 16-19) and 36 demographically similar non-using controls with DTI. The diffusion parameters fractional anisotropy (FA) and mean diffusivity (MD) were subjected to whole-brain voxelwise group comparisons using tract-based spatial statistics (Smith, S.M., Jenkinson, M., Johansen-Berg, H., Rueckert, D., Nichols, T.E., Mackay, C.E., Watkins, K.E., Ciccarelli, O., Cader, M.Z., Matthews, P.M., Behrens, T.E., 2006. Tract-based spatial statistics: voxelwise analysis of multi-subject diffusion data. Neuroimage 31, 1487-1505). MJ+ALC teens had significantly lower FA than controls in 10 regions, including left superior longitudinal fasciculus (SLF), left postcentral gyrus, bilateral crus cerebri, and inferior frontal and temporal white matter tracts. These diminutions occurred in the context of increased FA in right occipital, internal capsule, and SLF regions. Changes in MD were less distributed, but increased MD was evident in the right occipital lobe, whereas the left inferior longitudinal fasciculus showed lower MD in MJ+ALC users. Findings suggest that fronto-parietal circuitry may be particularly impacted in adolescent users of the most prevalent intoxicants: marijuana and alcohol. Disruptions to white matter in this young group could indicate aberrant axonal and myelin maturation with resultant compromise of fiber integrity. Findings of increased anisotropic diffusion in alternate brain regions suggest possible neuroadaptive processes and can be examined in future studies of connectivity to determine how aberrancies in specific tracts might influence efficient cognitive processing. PMID:19699064

Bava, Sunita; Frank, Lawrence R; McQueeny, Tim; Schweinsburg, Brian C; Schweinsburg, Alecia D; Tapert, Susan F

2009-08-20

97

Capture of inelastic dark matter in white dwarves  

SciTech Connect

We consider the capture of inelastic dark matter in white dwarves by inelastic spin-independent scattering on nuclei. We show that if the dark matter annihilates to standard-model particles then, under the assumption of primordial globular cluster formation, the observation of cold white dwarves in the globular cluster M4 appears inconsistent with explanations of the observed DAMA/LIBRA annual modulation signal based on spin-independent inelastic dark matter scattering. Alternatively if the inelastic dark matter scenario were to be confirmed and it was found to annihilate to standard-model particles then this would imply a much lower dark matter density in the core of M4 than would be expected if it were to have formed in a dark matter halo. Finally we argue that cold white dwarves constitute a unique dark matter probe, complementary to other direct and indirect detection searches.

McCullough, Matthew; Fairbairn, Malcolm [Rudolf Peierls Centre for Theoretical Physics, University of Oxford, 1 Keble Road, Oxford OX1 3NP (United Kingdom); Physics, King's College London, Strand WC2R 2LS (United Kingdom)

2010-04-15

98

Computational Atlases of Severity of White Matter Lesions in Elderly Subjects with MRI  

Microsoft Academic Search

\\u000a MRI of cerebral white matter may show regions of signal abnormalities. These changes may be associated with hypertension,\\u000a inflammation, or ischemia, as well as altered brain function. The goal of this work has been to construct computational atlases\\u000a of white matter lesions that represent both their severity as well as the frequency of their occurrence in a population to\\u000a achieve

Stathis Hadjidemetriou; Peter Lorenzen; Norbert Schuff; Susanne Mueller; Michael Weiner

2008-01-01

99

Breastfeeding and early white matter development: A cross-sectional study.  

PubMed

Does breastfeeding alter early brain development? The prevailing consensus from large epidemiological studies posits that early exclusive breastfeeding is associated with improved measures of IQ and cognitive functioning in later childhood and adolescence. Prior morphometric brain imaging studies support these findings, revealing increased white matter and sub-cortical gray matter volume, and parietal lobe cortical thickness, associated with IQ, in adolescents who were breastfed as infants compared to those who were exclusively formula-fed. Yet it remains unknown when these structural differences first manifest and when developmental differences that predict later performance improvements can be detected. In this study, we used quiet magnetic resonance imaging (MRI) scans to compare measures of white matter microstructure (mcDESPOT measures of myelin water fraction) in 133 healthy children from 10months through 4years of age, who were either exclusively breastfed a minimum of 3months; exclusively formula-fed; or received a mixture of breast milk and formula. We also examined the relationship between breastfeeding duration and white matter microstructure. Breastfed children exhibited increased white matter development in later maturing frontal and association brain regions. Positive relationships between white matter microstructure and breastfeeding duration are also exhibited in several brain regions, that are anatomically consistent with observed improvements in cognitive and behavioral performance measures. While the mechanisms underlying these structural differences remains unclear, our findings provide new insight into the earliest developmental advantages associated with breastfeeding, and support the hypothesis that breast milk constituents promote healthy neural growth and white matter development. PMID:23721722

Deoni, Sean C L; Dean, Douglas C; Piryatinsky, Irene; O'Muircheartaigh, Jonathan; Waskiewicz, Nicole; Lehman, Katie; Han, Michelle; Dirks, Holly

2013-05-28

100

White matter damage and cognitive impairment after traumatic brain injury.  

PubMed

White matter disruption is an important determinant of cognitive impairment after brain injury, but conventional neuroimaging underestimates its extent. In contrast, diffusion tensor imaging provides a validated and sensitive way of identifying the impact of axonal injury. The relationship between cognitive impairment after traumatic brain injury and white matter damage is likely to be complex. We applied a flexible technique-tract-based spatial statistics-to explore whether damage to specific white matter tracts is associated with particular patterns of cognitive impairment. The commonly affected domains of memory, executive function and information processing speed were investigated in 28 patients in the post-acute/chronic phase following traumatic brain injury and in 26 age-matched controls. Analysis of fractional anisotropy and diffusivity maps revealed widespread differences in white matter integrity between the groups. Patients showed large areas of reduced fractional anisotropy, as well as increased mean and axial diffusivities, compared with controls, despite the small amounts of cortical and white matter damage visible on standard imaging. A stratified analysis based on the presence or absence of microbleeds (a marker of diffuse axonal injury) revealed diffusion tensor imaging to be more sensitive than gradient-echo imaging to white matter damage. The location of white matter abnormality predicted cognitive function to some extent. The structure of the fornices was correlated with associative learning and memory across both patient and control groups, whilst the structure of frontal lobe connections showed relationships with executive function that differed in the two groups. These results highlight the complexity of the relationships between white matter structure and cognition. Although widespread and, sometimes, chronic abnormalities of white matter are identifiable following traumatic brain injury, the impact of these changes on cognitive function is likely to depend on damage to key pathways that link nodes in the distributed brain networks supporting high-level cognitive functions. PMID:21193486

Kinnunen, Kirsi Maria; Greenwood, Richard; Powell, Jane Hilary; Leech, Robert; Hawkins, Peter Charlie; Bonnelle, Valerie; Patel, Maneesh Chandrakant; Counsell, Serena Jane; Sharp, David James

2010-12-29

101

White matter integrity correlates of implicit sequence learning in healthy aging  

Microsoft Academic Search

Previous research has identified subcortical (caudate, putamen, hippocampus) and cortical (dorsolateral prefrontal cortex, DLPFC; frontal motor areas) regions involved in implicit sequence learning, with mixed findings for whether these neural substrates differ with aging. The present study used diffusion tensor imaging (DTI) tractography to reconstruct white matter connections between the known gray matter substrates, and integrity of these tracts was

Ilana J. Bennett; David J. Madden; Chandan J. Vaidya; James H. Howard Jr.; Darlene V. Howard

2010-01-01

102

Multiple white matter tract abnormalities underlie cognitive impairment in RRMS.  

PubMed

Diffusion tensor imaging (DTI) is a sensitive tool for detecting microstructural tissue damage in vivo. In this study, we investigated DTI abnormalities in individuals with relapsing remitting multiple sclerosis (RRMS) and examined the relations between imaging-based measures of white matter injury and cognitive impairment. DTI-derived metrics using tract-based spatial statistics (TBSS) were compared between 37 individuals with RRMS and 20 healthy controls. Cognitive impairment was assessed with three standard tests: the Symbol Digit Modalities Test (SDMT), which measures cognitive processing speed and visual working memory, the Rey Auditory Verbal Learning Test (RAVLT), which examines verbal memory, and the Paced Auditory Serial Addition Test (PASAT), which assesses sustained attention and working memory. Correlations between DTI-metrics and cognition were explored in regions demonstrating significant differences between the RRMS patients and the control group. Lower fractional anisotropy (FA) was found in RRMS participants compared to controls across the tract skeleton (0.40 ± 0.03 vs. 0.43 ± 0.01, p<0.01). In areas of reduced FA, mean diffusivity was increased and was dominated by increased radial diffusivity with no significant change in axial diffusivity, an indication of the role of damage to CNS myelin in MS pathology. In the RRMS group, voxelwise correlations were found between FA reduction and cognitive impairment in cognitively-relevant tracts, predominantly in the posterior thalamic radiation, the sagittal stratum, and the corpus callosum; the strongest correlations were with SDMT measures, with contributions to these associations from both lesion and normal-appearing white matter. Moreover, results using threshold-free cluster enhancement (TFCE) showed more widespread white matter involvement compared to cluster-based thresholding. These findings indicate the important role for DTI in delineating mechanisms underlying MS-associated cognitive impairment and suggest that DTI could play a critical role in monitoring the clinical and cognitive effects of the disease. PMID:22062194

Yu, Hui Jing; Christodoulou, Christopher; Bhise, Vikram; Greenblatt, Daniel; Patel, Yashma; Serafin, Dana; Maletic-Savatic, Mirjana; Krupp, Lauren B; Wagshul, Mark E

2011-10-29

103

Novel White Matter Tract Integrity Metrics Sensitive to Alzheimer Disease Progression.  

PubMed

BACKGROUND AND PURPOSE:Along with cortical abnormalities, white matter microstructural changes such as axonal loss and myelin breakdown are implicated in the pathogenesis of Alzheimer disease. Recently, a white matter model was introduced that relates non-Gaussian diffusional kurtosis imaging metrics to characteristics of white matter tract integrity, including the axonal water fraction, the intra-axonal diffusivity, and the extra-axonal axial and radial diffusivities.MATERIALS AND METHODS:This study reports these white matter tract integrity metrics in subjects with amnestic mild cognitive impairment (n = 12), Alzheimer disease (n = 14), and age-matched healthy controls (n = 15) in an effort to investigate their sensitivity, diagnostic accuracy, and associations with white matter changes through the course of Alzheimer disease.RESULTS:With tract-based spatial statistics and region-of-interest analyses, increased diffusivity in the extra-axonal space (extra-axonal axial and radial diffusivities) in several white matter tracts sensitively and accurately discriminated healthy controls from those with amnestic mild cognitive impairment (AUC = 0.82-0.95), while widespread decreased axonal water fraction discriminated amnestic mild cognitive impairment from Alzheimer disease (AUC = 0.84). Additionally, these white matter tract integrity metrics in the body of the corpus callosum were strongly correlated with processing speed in amnestic mild cognitive impairment (r = |0.80-0.82|, P < .001).CONCLUSIONS:These findings have implications for the course and spatial progression of white matter degeneration in Alzheimer disease, suggest the mechanisms by which these changes occur, and demonstrate the viability of these white matter tract integrity metrics as potential neuroimaging biomarkers of the earliest stages of Alzheimer disease and disease progression. PMID:23764722

Fieremans, E; Benitez, A; Jensen, J H; Falangola, M F; Tabesh, A; Deardorff, R L; Spampinato, M V S; Babb, J S; Novikov, D S; Ferris, S H; Helpern, J A

2013-06-13

104

White Matter Protection in Congenital Heart Surgery  

PubMed Central

Background Neurodevelopmental delays in motor skills and white matter (WM) injury have been documented in congenital heart disease (CHD) and after pediatric cardiac surgery. The lack of a suitable animal model has hampered our understanding of the cellular mechanisms underlying WM injury in these patients. Our aim is to identify an optimal surgical strategy for WM protection to reduce neurological injury in CHD patients. Methods and Results We developed a porcine cardiopulmonary bypass (CPB) model, which displays area dependent WM maturation. In this model, WM injury was identified following CPB-induced ischemia-reperfusion injury. The degree of injury was inversely correlated with the maturation stage, indicating maturation-dependent vulnerability of WM. Within different oligodendrocyte (OL) developmental stages, we show selective vulnerability of O4+ pre-OLs, while OL progenitor cells (OPCs) were resistant to insults. This indicates that immature WM is vulnerable to CPB-induced injury, but has an intrinsic potential for recovery mediated by endogenous OPCs. OPC number decreased with age, suggesting that earlier repair allows successful WM development. OPC proliferation was observed within a few days after CPB-induced ischemia-reperfusion injury; however by four weeks arrested OL maturation and delayed myelination were detected. Logistic model confirmed that maintaining higher oxygenation and reducing inflammation were effective in minimizing the risk of injury at immature stages of WM development. Conclusions Primary repair in neonates and young infants potentially provides successful WM development in CHD patients. Cardiac surgery during this susceptible period should avoid ischemia-reperfusion injury and minimize inflammation to prevent long-term WM-related neurological impairment.

Ishibashi, Nobuyuki; Scafidi, Joseph; Murata, Akira; Korotcova, Ludmila; Zurakowski, David; Gallo, Vittorio; Jonas, Richard A.

2012-01-01

105

Diminished performance on neuropsychological testing in late life depression is correlated with microstructural white matter abnormalities  

PubMed Central

Background Traditional T2 weighted MR imaging results are non-specific for the extent of underlying white matter structural abnormalities present in late life depression (LLD). Diffusion tensor imaging provides a unique opportunity to investigate the extent and nature of structural injury, but has been limited by examining only a subset of regions of interest (ROI) and by confounds common to the study of an elderly population, including comorbid vascular pathology. Furthermore, comprehensive correlation of diffusion tensor imaging (DTI) measurements, including axial and radial diffusivity measurements, has not been demonstrated in the late life depression population. Methods 51 depressed and 16 non-depressed, age- and cerebrovascular risk factor- matched elderly subjects underwent traditional anatomic T1 and T2 weight imaging, as well as DTI. The DTI data were skeletonized using tract based spatial statistics (TBSS), and both regional and global analyses were performed. Results Widespread structural abnormalities within white matter were detected in the LLD group, accounting for age, gender and education and matched for cerebrovascular risk factors and global T2 white matter hyperintensities (T2WMH). Regional differences were most prominent in uncinate and cingulate white matter and were generally characterized by an increase in radial diffusivity. Age-related changes particularly in the cingulate bundle were more advanced in individuals with LLD relative to controls. Regression analysis demonstrated significant correlations of regional fractional anisotropy and radial diffusivity with five different neuropsychological factor scores. TBSS analysis demonstrated a greater extent of white matter abnormalities in LLD not responsive to treatment, as compared to controls. Conclusions White matter integrity is compromised in late life depression, largely manifested by increased radial diffusivity in specific regions, suggesting underlying myelin injury. A possible mechanism for underlying myelin injury is chronic white matter ischemia related to intrinsic cerebrovascular disease. In some regions such as the cingulate bundle, the white matter injury related to late-life depression appears to be independent of and compounded by age-related changes. The correlations with neuropsychological testing indicate the essential effects of white matter injury on functional status. Lastly, response to treatment may depend on the extent of white matter injury, suggesting a need for intact functional networks.

Mettenburg, Joseph M; Benzinger, Tammie L.S.; Shimony, Joshua S; Snyder, Abraham Z.; Sheline, Yvette I

2012-01-01

106

White matter maturation supports the development of reasoning ability through its influence on processing speed.  

PubMed

The structure of the human brain changes in several ways throughout childhood and adolescence. Perhaps the most salient of these changes is the strengthening of white matter tracts that enable distal brain regions to communicate with one another more quickly and efficiently. Here, we sought to understand whether and how white matter changes contribute to improved reasoning ability over development. In particular, we sought to understand whether previously reported relationships between white matter microstructure and reasoning are mediated by processing speed. To this end, we analyzed diffusion tensor imaging data as well as data from standard psychometric tests of cognitive abilities from 103 individuals between the ages of 6 and 18. We used structural equation modeling to investigate the network of relationships between brain and behavior variables. Our analyses provide support for the hypothesis that white matter maturation (as indexed either by microstructural organization or volume) supports improved processing speed, which, in turn, supports improved reasoning ability. PMID:24118718

Ferrer, Emilio; Whitaker, Kirstie J; Steele, Joel S; Green, Chloe T; Wendelken, Carter; Bunge, Silvia A

2013-08-24

107

Smaller frontal lobe white matter volumes in depressed adolescents  

Microsoft Academic Search

BackgroundPrior studies have demonstrated reduced frontal lobe volumes in depressed adolescents. In this study, frontal lobe gray and white matter volumes in adolescents with major depressive disorder were evaluated.

Ronald J. Steingard; Perry F. Renshaw; John Hennen; Mara Lenox; Christina Bonella Cintron; Ashley D. Young; Daniel F. Connor; Trang H. Au; Deborah A. Yurgelun-Todd

2002-01-01

108

Neuron Deficit in the White Matter and Subplate in Periventricular Leukomalacia  

PubMed Central

Objective The cellular basis of cognitive abnormalities in preterm infants with periventricular leukomalacia (PVL) is uncertain. One important possibility is that damage to white matter and subplate neurons which are critical to the formation of the cerebral cortex occurs in conjunction with oligodendrocyte and axonal injury in PVL. We tested the hypothesis that the overall density of neurons in the white matter and subplate region is significantly lower in PVL cases compared to non-PVL controls. Methods We used a computer-based method for the determination of the density of MAP2-immunolabeled neurons in the ventricular/subventricular region, periventricular white matter, central white matter, and subplate region in PVL cases and controls. Results There were five subtypes of subcortical neurons: granular, unipolar, bipolar, inverted pyramidal, and multipolar. The neuronal density of the granular neurons in each of the four regions was 54–80% lower (p?0.01) in the PVL cases (n=15) compared to controls adjusted for age and postmortem interval (n=10). The overall densities of unipolar, bipolar, multipolar, and inverted pyramidal neurons did not differ significantly between the PVL cases and controls. No granular neurons expressed markers of neuronal and glial immaturity (Tuj1, doublecortin, or NG1). Interpretation These data suggest that quantitative deficits in susceptible granular neurons occur in the white matter distant from periventricular foci, including the subplate region, in PVL, and may contribute to abnormal cortical formation and cognitive dysfunction in preterm survivors.

Kinney, Hannah C.; Haynes, Robin L.; Xu, Gang; Andiman, Sarah E.; Folkerth, Rebecca D.; Sleeper, Lynn A; Volpe, Joseph J.

2012-01-01

109

Development of white matter pathways in typically developing preadolescent children  

PubMed Central

The first phase of major neuronal rearrangements in the brain takes place during the prenatal period. While the brain continues maturation throughout childhood, a critical second phase of synaptic overproduction and elimination takes place during the preadolescent period. Despite the importance of this developmental phase, few studies have evaluated neural changes taking place during this period. In this study, MRI Diffusion Tensor Imaging data from a normative sample of 126 preadolescent children (59 girls and 67 boys) between the ages of 6 and 10 years were analyzed in order to characterize age-relationships in the white matter microstructure. Tract Based Spatial Statistics (TBSS) method was used for whole brain analysis of white matter tracts without a priori assumption about the location of age associated differences. Our results demonstrate significant age-associated differences in most of the major fiber tracts bilaterally and along the whole body of the tracts. In contrast, developmental differences in the cingulum at the level of the parahippocampal region were only observed in the right hemisphere. We suggest that these age-relationships with a widespread distribution seen during the preadolescent years maybe relevant for the implementation of cognitive and social behaviors needed for a normal development into adulthood.

Muftuler, L. Tugan; Davis, Elysia Poggi; Buss, Claudia; Solodkin, Ana; Su, Min Ying; Head, Kevin M.; Hasso, Anton N.; Sandman, Curt A.

2012-01-01

110

White Matter Integrity and Behavioral Activation in Healthy Subjects  

PubMed Central

Individual differences in behavioral inhibition and behavioral activation may place certain people at greater risk for neuropsychiatric disorders and engagement in risky behaviors. Therefore, studying the neural correlates of behavioral inhibition and activation may help us understand neural mechanisms underlying risk behaviors in both clinical and non-clinical populations. To investigate, we assessed the relationships between white matter integrity and measures of behavioral inhibition and behavioral activation in 51 healthy participants using diffusion tensor imaging (DTI) and the Behavioral Inhibition System/Behavioral Activation System (BIS/BAS) scale. Scores on the Fun-Seeking subscale of the BAS positively correlated with DTI fractional anisotropy (FA) in the left corona radiata and adjacent superior longitudinal fasciculus, and with mean diffusivity (MD) in the left inferior longitudinal fasciculus and inferior fronto-occipital fasciculus after controlling for age, gender, and education. These findings suggest that the integrity of white matter connecting extensive brain regions implicated in self-control and the processing of rewards and emotions are associated with individual differences in the motivation for seeking and participating in fun and novel experiences.

Xu, Jiansong; Kober, Hedy; Carroll, Kathleen M.; Rounsaville, Bruce J.; Pearlson, Godfrey D.; Potenza, Marc N.

2011-01-01

111

Brain white matter structural properties predict transition to chronic pain.  

PubMed

Neural mechanisms mediating the transition from acute to chronic pain remain largely unknown. In a longitudinal brain imaging study, we followed up patients with a single sub-acute back pain (SBP) episode for more than 1year as their pain recovered (SBPr), or persisted (SBPp) representing a transition to chronic pain. We discovered brain white matter structural abnormalities (n=24 SBP patients; SBPp=12 and SBPr=12), as measured by diffusion tensor imaging (DTI), at entry into the study in SBPp in comparison to SBPr. These white matter fractional anisotropy (FA) differences accurately predicted pain persistence over the next year, which was validated in a second cohort (n=22 SBP patients; SBPp=11 and SBPr=11), and showed no further alterations over a 1-year period. Tractography analysis indicated that abnormal regional FA was linked to differential structural connectivity to medial vs lateral prefrontal cortex. Local FA was correlated with functional connectivity between medial prefrontal cortex and nucleus accumbens in SBPr. As we have earlier shown that the latter functional connectivity accurately predicts transition to chronic pain, we can conclude that brain structural differences, most likely existing before the back pain-inciting event and independent of the back pain, predispose subjects to pain chronification. PMID:24040975

Mansour, Ali R; Baliki, Marwan N; Huang, Lejian; Torbey, Souraya; Herrmann, Kristi M; Schnitzer, Thomas J; Apkarian, A Vania

2013-10-01

112

White matter integrity and behavioral activation in healthy subjects.  

PubMed

Individual differences in behavioral inhibition and behavioral activation may place certain people at greater risk for neuropsychiatric disorders and engagement in risky behaviors. Therefore, studying the neural correlates of behavioral inhibition and activation may help us understand neural mechanisms underlying risk behaviors in both clinical and non-clinical populations. To investigate, we assessed the relationships between white matter integrity and measures of behavioral inhibition and behavioral activation in 51 healthy participants using diffusion tensor imaging (DTI) and the Behavioral Inhibition System/Behavioral Activation System (BIS/BAS) scale. Scores on the Fun-Seeking subscale of the BAS positively correlated with DTI fractional anisotropy in the left corona radiata and adjacent superior longitudinal fasciculus, and with mean diffusivity in the left inferior longitudinal fasciculus and inferior fronto-occipital fasciculus after controlling for age, gender, and education. These findings suggest that the integrity of white matter connecting extensive brain regions implicated in self-control and the processing of rewards and emotions are associated with individual differences in the motivation for seeking and participating in fun and novel experiences. PMID:21618658

Xu, Jiansong; Kober, Hedy; Carroll, Kathleen M; Rounsaville, Bruce J; Pearlson, Godfrey D; Potenza, Marc N

2011-05-26

113

Detection of DTI White Matter Abnormalities in Multiple Sclerosis Patients  

PubMed Central

The emergence of new modalities such as Diffusion Tensor Imaging (DTI) is of great interest for the characterization and the temporal study of Multiple Sclerosis (MS). DTI indeed gives information on water diffusion within tissues and could therefore reveal alterations in white matter fibers before being visible in conventional MRI. However, recent studies generally rely on scalar measures derived from the tensors such as FA or MD instead of using the full tensor itself. Therefore, a certain amount of information is left unused. In this article, we present a framework to study the benefits of using the whole diffusion tensor information to detect statistically significant differences between each individual MS patient and a database of control subjects. This framework, based on the comparison of the MS patient DTI and a mean DTI atlas built from the control subjects, allows us to look for differences both in normally appearing white matter but also in and around the lesions of each patient. We present a study on a database of 11 MS patients, showing the ability of the DTI to detect not only significant differences on the lesions but also in regions around them, enabling an early detection of an extension of the MS disease.

Commowick, Olivier; Fillard, Pierre; Clatz, Olivier; Warfield, Simon K.

2008-01-01

114

Heterogeneity in age-related white matter changes  

Microsoft Academic Search

White matter changes occur endemically in routine magnetic resonance imaging (MRI) scans of elderly persons. MRI appearance\\u000a and histopathological correlates of white matter changes are heterogeneous. Smooth periventricular hyperintensities, including\\u000a caps around the ventricular horns, periventricular lining and halos are likely to be of non-vascular origin. They relate to\\u000a a disruption of the ependymal lining with subependymal widening of the

Reinhold Schmidt; Helena Schmidt; Johannes Haybaeck; Marisa Loitfelder; Serge Weis; Margherita Cavalieri; Stephan Seiler; Christian Enzinger; Stefan Ropele; Timo Erkinjuntti; Leonardo Pantoni; Philip Scheltens; Franz Fazekas; Kurt Jellinger

2011-01-01

115

White Matter and Cognition in Adults Who Were Born Preterm  

Microsoft Academic Search

Background and PurposeIndividuals born very preterm (before 33 weeks of gestation, VPT) are at risk of damage to developing white matter, which may affect later cognition and behaviour.MethodsWe used diffusion tensor MRI (DT-MRI) to assess white matter microstructure (fractional anisotropy; FA) in 80 VPT and 41 term-born individuals (mean age 19.1 years, range 17–22, and 18.5 years, range17–22 years, respectively).

Matthew P. G. Allin; Dimitris Kontis; Muriel Walshe; John Wyatt; Gareth J. Barker; Richard A. A. Kanaan; Philip McGuire; Larry Rifkin; Robin M. Murray; Chiara Nosarti; Joseph Najbauer

2011-01-01

116

Pathophysiology of Age-Related Cerebral White Matter Changes  

Microsoft Academic Search

The pathogenesis of age-related cerebral white matter changes (WMC) is still a matter of investigation. Alterations of deep small vessels, such as arteriolosclerosis, are considered to play a central role in the development of WMC. Stenosis or occlusion of small vessels may cause sudden or more chronic ischemia resulting in small areas of necrosis (lacunar infarction) or diffuse alterations consistent

Leonardo Pantoni

2002-01-01

117

Neonatal White Matter Abnormalities an Important Predictor of Neurocognitive Outcome for Very Preterm Children  

PubMed Central

Background Cerebral white matter abnormalities on term MRI are a strong predictor of motor disability in children born very preterm. However, their contribution to cognitive impairment is less certain. Objective Examine relationships between the presence and severity of cerebral white matter abnormalities on neonatal MRI and a range of neurocognitive outcomes assessed at ages 4 and 6 years. Design/Methods The study sample consisted of a regionally representative cohort of 104 very preterm (?32 weeks gestation) infants born from 1998–2000 and a comparison group of 107 full-term infants. At term equivalent, all preterm infants underwent a structural MRI scan that was analyzed qualitatively for the presence and severity of cerebral white matter abnormalities, including cysts, signal abnormalities, loss of white matter volume, ventriculomegaly, and corpus callosal thinning/myelination. At corrected ages 4 and 6 years, all children underwent a comprehensive neurodevelopmental assessment that included measures of general intellectual ability, language development, and executive functioning. Results At 4 and 6 years, very preterm children without cerebral white matter abnormalities showed no apparent neurocognitive impairments relative to their full-term peers on any of the domain specific measures of intelligence, language, and executive functioning. In contrast, children born very preterm with mild and moderate-to-severe white matter abnormalities were characterized by performance impairments across all measures and time points, with more severe cerebral abnormalities being associated with increased risks of cognitive impairment. These associations persisted after adjustment for gender, neonatal medical risk factors, and family social risk. Conclusions Findings highlight the importance of cerebral white matter connectivity for later intact cognitive functioning amongst children born very preterm. Preterm born children without cerebral white matter abnormalities on their term MRI appear to be spared many of the cognitive impairments commonly associated with preterm birth. Further follow-up will be important to assess whether this finding persists into the school years.

Woodward, Lianne J.; Clark, Caron A. C.; Bora, Samudragupta; Inder, Terrie E.

2012-01-01

118

White matter abnormalities and structural hippocampal disconnections in amnestic mild cognitive impairment and Alzheimer's disease.  

PubMed

The purpose of this project was to evaluate white matter degeneration and its impact on hippocampal structural connectivity in patients with amnestic mild cognitive impairment, non-amnestic mild cognitive impairment and Alzheimer's disease. We estimated white matter fractional anisotropy, mean diffusivity and hippocampal structural connectivity in two independent cohorts. The ADNI cohort included 108 subjects [25 cognitively normal, 21 amnestic mild cognitive impairment, 47 non-amnestic mild cognitive impairment and 15 Alzheimer's disease]. A second cohort included 34 subjects [15 cognitively normal and 19 amnestic mild cognitive impairment] recruited in Montreal. All subjects underwent clinical and neuropsychological assessment in addition to diffusion and T1 MRI. Individual fractional anisotropy and mean diffusivity maps were generated using FSL-DTIfit. In addition, hippocampal structural connectivity maps expressing the probability of connectivity between the hippocampus and cortex were generated using a pipeline based on FSL-probtrackX. Voxel-based group comparison statistics of fractional anisotropy, mean diffusivity and hippocampal structural connectivity were estimated using Tract-Based Spatial Statistics. The proportion of abnormal to total white matter volume was estimated using the total volume of the white matter skeleton. We found that in both cohorts, amnestic mild cognitive impairment patients had 27-29% white matter volume showing higher mean diffusivity but no significant fractional anisotropy abnormalities. No fractional anisotropy or mean diffusivity differences were observed between non-amnestic mild cognitive impairment patients and cognitively normal subjects. Alzheimer's disease patients had 66.3% of normalized white matter volume with increased mean diffusivity and 54.3% of the white matter had reduced fractional anisotropy. Reduced structural connectivity was found in the hippocampal connections to temporal, inferior parietal, posterior cingulate and frontal regions only in the Alzheimer's group. The severity of white matter degeneration appears to be higher in advanced clinical stages, supporting the construct that these abnormalities are part of the pathophysiological processes of Alzheimer's disease. PMID:24086371

Rowley, Jared; Fonov, Vladimir; Wu, Ona; Eskildsen, Simon Fristed; Schoemaker, Dorothee; Wu, Liyong; Mohades, Sara; Shin, Monica; Sziklas, Viviane; Cheewakriengkrai, Laksanun; Shmuel, Amir; Dagher, Alain; Gauthier, Serge; Rosa-Neto, Pedro

2013-09-27

119

White Matter Abnormalities and Structural Hippocampal Disconnections in Amnestic Mild Cognitive Impairment and Alzheimer's Disease  

PubMed Central

The purpose of this project was to evaluate white matter degeneration and its impact on hippocampal structural connectivity in patients with amnestic mild cognitive impairment, non-amnestic mild cognitive impairment and Alzheimer’s disease. We estimated white matter fractional anisotropy, mean diffusivity and hippocampal structural connectivity in two independent cohorts. The ADNI cohort included 108 subjects [25 cognitively normal, 21 amnestic mild cognitive impairment, 47 non-amnestic mild cognitive impairment and 15 Alzheimer’s disease]. A second cohort included 34 subjects [15 cognitively normal and 19 amnestic mild cognitive impairment] recruited in Montreal. All subjects underwent clinical and neuropsychological assessment in addition to diffusion and T1 MRI. Individual fractional anisotropy and mean diffusivity maps were generated using FSL-DTIfit. In addition, hippocampal structural connectivity maps expressing the probability of connectivity between the hippocampus and cortex were generated using a pipeline based on FSL-probtrackX. Voxel-based group comparison statistics of fractional anisotropy, mean diffusivity and hippocampal structural connectivity were estimated using Tract-Based Spatial Statistics. The proportion of abnormal to total white matter volume was estimated using the total volume of the white matter skeleton. We found that in both cohorts, amnestic mild cognitive impairment patients had 27-29% white matter volume showing higher mean diffusivity but no significant fractional anisotropy abnormalities. No fractional anisotropy or mean diffusivity differences were observed between non-amnestic mild cognitive impairment patients and cognitively normal subjects. Alzheimer’s disease patients had 66.3% of normalized white matter volume with increased mean diffusivity and 54.3% of the white matter had reduced fractional anisotropy. Reduced structural connectivity was found in the hippocampal connections to temporal, inferior parietal, posterior cingulate and frontal regions only in the Alzheimer’s group. The severity of white matter degeneration appears to be higher in advanced clinical stages, supporting the construct that these abnormalities are part of the pathophysiological processes of Alzheimer’s disease.

Rowley, Jared; Fonov, Vladimir; Wu, Ona; Eskildsen, Simon Fristed; Schoemaker, Dorothee; Wu, Liyong; Mohades, Sara; Shin, Monica; Sziklas, Viviane; Cheewakriengkrai, Laksanun; Shmuel, Amir; Dagher, Alain; Gauthier, Serge; Rosa-Neto, Pedro

2013-01-01

120

Focal white matter density changes in schizophrenia: reduced inter-hemispheric connectivity.  

PubMed

Gray matter changes have been demonstrated in several regions in schizophrenia. Particularly, the frontal and temporal cortices and amygdala-hippocampal region have been found decreased in volume and density in magnetic resonance imaging (MRI) studies. These abnormalities may reflect an aberrant neuronal network in schizophrenia, suggesting that white matter fibers connecting these regions may also be affected. However, it is unclear if particular white matter areas are (progressively) affected in schizophrenia and if these are related to the gray matter changes. Focal white matter changes in schizophrenia were studied in whole brain magnetic resonance images acquired from 159 patients with schizophrenia or schizophreniform disorder and 158 healthy comparison subjects using voxel-based morphometry. White matter density changes in the patients with schizophrenia were correlated to gray matter density changes and to illness severity. In the patients with schizophrenia, significant decreases in white matter density were found in the genu and truncus of the corpus callosum in the left and right hemisphere, in the right anterior internal capsule and in the right anterior commissure. No interactions between diagnosis and age were found. Increased illness severity was correlated with low density of the corpus callosum and anterior commissure. Decreased corpus callosum density correlated with decreased density of thalamus, lateral inferior frontal and insular gray matter in patients and controls and with decreased density of medial orbitofrontal and superior temporal gyri in patients. Decreased internal capsule and anterior commissure density correlated with increased caudate, and globus pallidus density in patients and controls. These findings suggest aberrant inter-hemispheric connectivity of anterior cortical and sub-cortical brain regions in schizophrenia, reflecting decreased hemispheric specialisation in schizophrenia. PMID:14741639

Hulshoff Pol, Hilleke E; Schnack, Hugo G; Mandl, René C W; Cahn, W; Collins, D Louis; Evans, Alan C; Kahn, René S

2004-01-01

121

White matter integrity in hair-pulling disorder (trichotillomania).  

PubMed

Hair-pulling disorder (trichotillomania, HPD) is a disabling condition that is characterized by repetitive hair-pulling resulting in hair loss. Although there is evidence of structural grey matter abnormalities in HPD, there is a paucity of data on white matter integrity. The aim of this study was to explore white matter integrity using diffusion tensor imaging (DTI) in subjects with HPD and healthy controls. Sixteen adult female subjects with HPD and 13 healthy female controls underwent DTI. Hair-pulling symptom severity, anxiety and depressive symptoms were also assessed. Tract-based spatial statistics were used to analyze data on fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD) and radial diffusivity (RD). There were no differences in DTI measures between HPD subjects and healthy controls. However, there were significant associations of increased MD in white matter tracts of the fronto-striatal-thalamic pathway with longer HPD duration and increased HPD severity. Our findings suggest that white matter integrity in fronto-striatal-thalamic pathways in HPD is related to symptom duration and severity. The molecular basis of measures of white matter integrity in HPD deserves further exploration. PMID:23149033

Roos, Annerine; Fouche, Jean-Paul; Stein, Dan J; Lochner, Christine

2012-11-11

122

Morphological changes in white matter astrocytes in response to hypoxia\\/ischemia in the neonatal pig  

Microsoft Academic Search

White matter damage is a significant problem in the human pre-term baby. Damage to white matter is usually associated with injury or insults to babies born prematurely, typically before 32weeks' gestation, however there is increasing evidence of both grey and white matter damage occurring after 32weeks' gestation. Astrocytes play a vital role in white matter, regulating molecules such as glutamate

Susan M. Sullivan; S. Tracey Björkman; Stephanie M. Miller; Paul B. Colditz; David V. Pow

2010-01-01

123

Different associations of white matter lesions with depression and cognition  

PubMed Central

Background To test the hypothesis that white matter lesions (WML) are primarily associated with regional frontal cortical volumes, and to determine the mediating effects of these regional frontal cortices on the associations of WML with depressive symptoms and cognitive dysfunction. Methods Structural brains MRIs were performed on 161 participants: cognitively normal, cognitive impaired but not demented, and demented participants. Lobar WML volumes, regional frontal cortical volumes, depressive symptom severity, and cognitive abilities were measured. Multiple linear regression analyses were used to identify WML volume effects on frontal cortical volume. Structural equation modeling was used to determine the MRI-depression and the MRI-cognition path relationships. Results WML predicted frontal cortical volume, particularly in medial orbirtofrontal cortex, irrespective of age, gender, education, and group status. WML directly predicted depressive score, and this relationship was not mediated by regional frontal cortices. In contrast, the association between WML and cognitive function was indirect and mediated by regional frontal cortices. Conclusions These findings suggest that the neurobiological mechanisms underpinning depressive symptoms and cognitive dysfunction in older adults may differ.

2012-01-01

124

White matter lateralization and interhemispheric coherence to auditory modulations in normal reading and dyslexic adults.  

PubMed

Neural activation of slow acoustic variations that are important for syllable identification is more lateralized to the right hemisphere than activation of fast acoustic changes that are important for phoneme identification. It has been suggested that this complementary function at different hemispheres is rooted in a different degree of white matter myelination in the left versus right hemisphere. The present study will investigate this structure-function relationship with Diffusion Tensor Imaging (DTI) and Auditory Steady-State Responses (ASSR), respectively. With DTI we examined white matter lateralization in the cortical auditory and language regions (i.e. posterior region of the superior temporal gyrus and the arcuate fasciculus) and white matter integrity in the splenium of the corpus callosum. With ASSR we examined interhemispheric coherence to slow, syllabic-rate (i.e. 4Hz) and fast, phonemic-rate (i.e. 20Hz) modulations. These structural and functional techniques were applied in a group of normal reading adults and a group of dyslexic adults for whom previously reduced functional interhemispheric connectivity at 20Hz has been reported (Poelmans et al. (2012). Ear and Hearing, 33, 134-143). This sample was chosen since it is hypothesized that in dyslexic readers insufficient hemispheric asymmetry in myelination might relate to their auditory and phonological problems. Results demonstrate reduced white matter lateralization in the posterior superior temporal gyrus and the arcuate fasciculus in the dyslexic readers. Additionally, white matter lateralization in the posterior superior temporal gyrus and white matter integrity in the splenium of the corpus callosum related to interhemispheric coherence to phonemic-rate modulations (i.e. 20Hz). Interestingly, this correlation pattern was opposite in normal versus dyslexic readers. These results might imply that less pronounced left white matter dominance in dyslexic adults might relate to their problems to process phonemic-rate acoustic information and to integrate them into the phonological system. PMID:23872049

Vandermosten, Maaike; Poelmans, Hanne; Sunaert, Stefan; Ghesquière, Pol; Wouters, Jan

2013-07-18

125

Spatial characteristics of white matter abnormalities in schizophrenia.  

PubMed

There is considerable evidence implicating brain white matter (WM) abnormalities in the pathophysiology of schizophrenia; however, the spatial localization of WM abnormalities reported in the existing studies is heterogeneous. Thus, the goal of this study was to quantify the spatial characteristics of WM abnormalities in schizophrenia. One hundred and fourteen patients with schizophrenia and 138 matched controls participated in this multisite study involving the Universities of Iowa, Minnesota, and New Mexico, and the Massachusetts General Hospital. We measured fractional anisotropy (FA) in brain WM regions extracted using 3 different image-processing algorithms: regions of interest, tract-based spatial statistics, and the pothole approach. We found that FA was significantly lower in patients using each of the 3 image-processing algorithms. The region-of-interest approach showed multiple regions with lower FA in patients with schizophrenia, with overlap at all 4 sites in the corpus callosum and posterior thalamic radiation. The tract-based spatial statistic approach showed (1) global differences in 3 of the 4 cohorts and (2) lower frontal FA at the Iowa site. Finally, the pothole approach showed a significantly greater number of WM potholes in patients compared to controls at each of the 4 sites. In conclusion, the spatial characteristics of WM abnormalities in schizophrenia reflect a combination of a global low-level decrease in FA, suggesting a diffuse process, coupled with widely dispersed focal reductions in FA that vary spatially among individuals (ie, potholes). PMID:22987296

White, Tonya; Ehrlich, Stefan; Ho, Beng-Choon; Manoach, Dara S; Caprihan, Arvind; Schulz, S Charles; Andreasen, Nancy C; Gollub, Randy L; Calhoun, Vince D; Magnotta, Vincent A

2012-09-16

126

Diffuse Abnormality of Low to Moderately Organized White Matter in Schizophrenia  

PubMed Central

Abstract Increasing evidence suggests that abnormal white matter is central to the pathophysiology and, potentially, the pathogenesis of schizophrenia (SCZ). The spatial distribution of observed abnormalities and the type of white matter involved remain to be elucidated. Seventeen chronically ill individuals with SCZ and 17 age- and gender-matched controls were studied using a 3T magnetic resonance imaging diffusion tensor imaging protocol designed to examine the abnormalities of white matter by region and by level of architectural infrastructure as assessed by fractional anisotropy (FA) in native space. After assessing whole-brain FA, FA was divided into quartiles, capturing all brain regions with FA values from 0 to 0.25, 0.25 to 0.5, 0.5 to 0.75, and 0.75 to 1.0. Mean whole-brain FA was 4.6% smaller in the SCZ group than in healthy controls. This difference was largely accounted for by FA values from the second quartile (between 0.25 and 0.5). Second quartile FA was decreased in all 130 brain regions of the template in the SCZ group, with the difference reaching statistical significance in 41 regions. Correspondingly, the amount of brain tissue with an FA of ?0.4 was significantly reduced in the SCZ group, while the amount of brain tissue falling in the lowest quartile of FA was increased. These findings strongly imply a diffuse loss of white matter integrity in SCZ. Our finding that the loss of integrity disproportionately involves white matter of low to moderate organization suggests an approach to the specificity of white matter abnormalities in SCZ based on microstructure rather than spatial distribution.

Reading, Sarah A. J.; Oishi, Kenichi; Redgrave, Graham W.; McEntee, Julie; Shanahan, Megan; Yoritomo, Nadine; Younes, Laurent; Mori, Susumu; Miller, Michael I.; van Zijl, Peter; Ross, Christopher A.

2011-01-01

127

White Matter Abnormalities in Pediatric Obsessive-Compulsive Disorder  

PubMed Central

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.

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

2012-01-01

128

Cognitive dysfunction and white matter abnormalities in antiphospholipid syndrome.  

PubMed

Diagnosis of the antiphospholipid syndrome (APS) requires that a patient have both a clinical event (thrombosis or pregnancy loss) and persistently positive antiphospholipid antibodies (aPL). Although stroke and transient ischemic attack are the most common neurologic manifestations of APS, both cognitive dysfunction and magnetic resonance imaging (MRI) white matter hyperintensities can occur in aPL-positive patients (with or without APS). Relatively little is known about the cognitive pattern in aPL-positive patients; MRI white matter hyperintensities may be related to underlying attentional and executive cognitive impairment. Studies with sophisticated neuroimaging techniques aimed to better understand MRI white matter hyperintensities may eventually facilitate our understanding of cognitive dysfunction in aPL-positive patients. PMID:20472406

Erkan, Doruk; Kozora, Elizabeth; Lockshin, Michael D

2010-05-15

129

White matter damage of patients with Alzheimer's disease correlated with the decreased cognitive function.  

PubMed

Increasing evidence demonstrates that there is marked damage and dysfunction in the white matter in Alzheimer's disease (AD). The present study investigates the nature of white matter damage of patients with Alzheimer's disease with diffusion tensor magnetic resonance imaging (DTI) and analyses the relationship between the white matter damage and the cognition function. DTI, as well as T1 fluid attenuated inversion recovery (FLAIR) and T2-FLAIR, was performed on probable patients of Alzheimer's disease, and sex and age matched healthy volunteers to measure the fractional anisotropy (FA) and mean diffusivity (MD) in the genu and splenium of the corpus callosum, anterior and posterior limbs of the internal capsule, and the white matter of frontal, temporal, parietal, and occipital lobes. FA was lower in the splenium of corpus callosum, as well as in the white matter of the frontal, temporal, and parietal lobes from patients with Alzheimer's disease than in the corresponding region from healthy controls and was strongly positive correlated with MMSE scores, whereas FA appeared no different in the anterior and posterior limbs of internal capsule, occipital lobes white matter, and the genu of corpus callosum between the patients and healthy controls. MD was significantly higher in the splenium of corpus callosum and parietal lobes white matter from patients than in that those from healthy controls and was strongly negative correlated with MMSE scores, whereas MD in the anterior and posterior limbs of internal capsule, as well as in frontal, temporal, occipital lobes white matter and the genu of corpus callosum, was not different between the patients and healthy controls. The most prominent alteration of FA and MD was in the splenium of corpus callosum. Our results suggested that white matter of patients with Alzheimer's disease was selectively impaired and the extent of damage had a strong correlation with the cognitive function, and that selective impairment reflected the cortico-cortical and cortico-subcortical disconnections in the pathomechanism of Alzheimer's disease. The values of FA and MD in white matter, especially in the splenium of corpus callosum in AD patients, might be a more appropriate surrogate marker for monitoring the disease progression. PMID:16614789

Duan, Jin-Hai; Wang, Hua-Qiao; Xu, Jie; Lin, Xian; Chen, Shao-Qiong; Kang, Zhuang; Yao, Zhi-Bin

2006-04-14

130

Compression behavior of porcine spinal cord white matter.  

PubMed

Spinal cord injury often results from a compressive load; however, the compression behavior of spinal cord white matter has not been clearly established. Quantifying the compression behavior is important for advancing our understanding of spinal cord injury mechanics and facilitating the use of finite element models to study injury. The objective of this study was to characterize the unconfined compression behavior of isolated white matter segments and determine the constitutive model which best captured the stress-strain behavior. Spinal cord white matter samples were harvested immediately following sacrifice from juvenile Yorkshire pigs (n=104). The samples were compressed to 40% strain at four strain rates (0.005, 0.05, 0.5, and 5.0/s) and allowed to relax for 60s. The effects of preload, peak strain, sample aspect ratio, and time post mortem on peak stress, and constitutive model parameters were also examined. Strain rate had a significant effect on peak stress (p<0.001). A first-order Ogden model best captured the loading response of spinal cord white matter (R(2)=0.99) and a viscoelastic material model combining a first-order Ogden model with a 3-term Prony series effectively captured the effect of strain rate and the relaxation response. This study showed spinal cord white matter to be less stiff than previously estimated by inverse finite element methods, which will have a significant effect on finite element model predictions of the magnitude and distribution of stresses and strains in the spinal cord. This study is the first to quantify the unconfined compression response of spinal cord white matter. PMID:21353225

Sparrey, Carolyn J; Keaveny, Tony M

2011-02-25

131

Infrared spectroscopic characterization of human white matter, grey matter, and multiple sclerosis lesions  

NASA Astrophysics Data System (ADS)

FT-IR spectroscopy has been used to characterize white matter, grey matter, and multiple sclerosis (MS) plaques from human central nervous system (CNS) tissue. Discrimination among these three tissue types is possible due to variations in composition. Spectra of white matter exhibit strong lipid absorptions. In contrast, spectra of grey matter reveal a reduced lipid contribution and a significant absorption from water. MS plaques exhibit spectra indicative of lipid loss and, depending upon whether the plaques are chronic or acute, changes in the protein and/or water content.

Choo, Lin-P'ing; Jackson, Michael; Halliday, William C.; Mantsch, Henry H.

1994-01-01

132

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

PubMed Central

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.

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

2012-01-01

133

Loss of cerebral white matter structural integrity tracks the gray matter metabolic decline in normal aging?  

PubMed Central

Relationships between structural MRI-based markers of declining cerebral integrity, and regional PET measurements of 18FDG uptake have not been studied well in normal aging. In this manuscript we relate changes in cerebral morphology to regional cerebral glucose uptake for 14 major cortical areas in 19 healthy older individuals (age 59–92 years). Measurements of cerebral integrity included gray matter (GM) thickness, sulcal and intergyral spans, fractional anisotropy (FA) of water diffusion and volume of hyperintense WM (HWM) lesions. 18FDG-PET measurements were converted to standard uptake values and corrected for partial volume artifact. Following this, cortical FDG uptake was significantly correlated with several indices of WM integrity that we previously observed to be sensitive to cognitive decline in executive function, including intergyral span and HWM volumes. Our findings suggest that the age-related decline in white matter integrity, observed as increases in HWM lesions, intergyral spans and reduction in FA, correlated with a decline in the global and regional cerebral glucose uptake. Our findings support the emerging consensus that WM integrity indices are sensitive predictors of declining cerebral health in normal aging. Specifically, age-related WM degradation in the thinly myelinated association tracts appears to track the decreases in global and regional rates of glucose uptake.

Kochunov, P.; Ramage, A.E.; Lancaster, J.L.; Robin, D.A.; Narayana, S.; Coyle, T.; Royall, D.R.; Fox, P.

2009-01-01

134

Loss of cerebral white matter structural integrity tracks the gray matter metabolic decline in normal aging.  

PubMed

Relationships between structural MRI-based markers of declining cerebral integrity, and regional PET measurements of (18)FDG uptake have not been studied well in normal aging. In this manuscript we relate changes in cerebral morphology to regional cerebral glucose uptake for 14 major cortical areas in 19 healthy older individuals (age 59-92 years). Measurements of cerebral integrity included gray matter (GM) thickness, sulcal and intergyral spans, fractional anisotropy (FA) of water diffusion and volume of hyperintense WM (HWM) lesions. (18)FDG-PET measurements were converted to standard uptake values and corrected for partial volume artifact. Following this, cortical FDG uptake was significantly correlated with several indices of WM integrity that we previously observed to be sensitive to cognitive decline in executive function, including intergyral span and HWM volumes. Our findings suggest that the age-related decline in white matter integrity, observed as increases in HWM lesions, intergyral spans and reduction in FA, correlated with a decline in the global and regional cerebral glucose uptake. Our findings support the emerging consensus that WM integrity indices are sensitive predictors of declining cerebral health in normal aging. Specifically, age-related WM degradation in the thinly myelinated association tracts appears to track the decreases in global and regional rates of glucose uptake. PMID:19095067

Kochunov, P; Ramage, A E; Lancaster, J L; Robin, D A; Narayana, S; Coyle, T; Royall, D R; Fox, P

2008-11-25

135

Alterations of mean diffusivity in brain white matter and deep gray matter in Parkinson's disease.  

PubMed

Although Parkinson's disease is a neurodegenerative disease primarily involving basal ganglia and midbrain, the deficit of white matter is also involved during the disease progression. As the diffusion tensor imaging method is sensitive to the microstructural changes, we investigated the microstructural alterations in white matter and deep gray matter in patients with Parkinson's disease. Brain images of 64 patients and sex- and age-matched 64 healthy controls were obtained from a 3T MRI scanner. Tract-based spatial statistics were used to compare the mean diffusivity of the white matter tract between the groups. Voxel-based analysis was used to compare the mean diffusivity of the subcortical gray matter between the groups. There were white matter deficits in the corticofugal tract, cingulum, uncinate fasciculus, crus of fornix or stria terminalis, corpus callosum, external capsule, superior longitudinal fasciculus, posterior thalamic radiation including optic radiation, and the tracts adjacent to the precuneus and supramarginal gyrus, as indicated by higher mean diffusivity in Parkinson's disease patients than in controls. There were also deficits in the left putamen, pallidum, thalamus, and caudate as indicated by higher mean diffusivity in Parkinson's disease patients than in controls. Using diffusion tensor imaging and multi-methods of image analysis, we successfully characterized and visualized brain white matter and deep gray matter areas with microstructural deficits in Parkinson's disease patients. PMID:23831353

Kim, Hengjun J; Kim, Sang Joon; Kim, Ho Sung; Choi, Choong Gon; Kim, Namkug; Han, Seungbong; Jang, Eun Hye; Chung, Sun J; Lee, Chong Sik

2013-07-03

136

Tissue plasminogen activator prevents white matter damage following stroke  

PubMed Central

Tissue plasminogen activator (tPA) is the only available treatment for acute stroke. In addition to its vascular fibrinolytic action, tPA exerts various effects within the brain, ranging from synaptic plasticity to control of cell fate. To date, the influence of tPA in the ischemic brain has only been investigated on neuronal, microglial, and endothelial fate. We addressed the mechanism of action of tPA on oligodendrocyte (OL) survival and on the extent of white matter lesions in stroke. We also investigated the impact of aging on these processes. We observed that, in parallel to reduced levels of tPA in OLs, white matter gets more susceptible to ischemia in old mice. Interestingly, tPA protects murine and human OLs from apoptosis through an unexpected cytokine-like effect by the virtue of its epidermal growth factor–like domain. When injected into aged animals, tPA, although toxic to the gray matter, rescues white matter from ischemia independently of its proteolytic activity. These studies reveal a novel mechanism of action of tPA and unveil OL as a target cell for cytokine effects of tPA in brain diseases. They show overall that tPA protects white matter from stroke-induced lesions, an effect which may contribute to the global benefit of tPA-based stroke treatment.

Correa, Fernando; Gauberti, Maxime; Parcq, Jerome; Macrez, Richard; Hommet, Yannick; Obiang, Pauline; Hernangomez, Miriam; Montagne, Axel; Liot, Geraldine; Guaza, Carmen; Maubert, Eric; Ali, Carine; Vivien, Denis

2011-01-01

137

Tissue plasminogen activator prevents white matter damage following stroke.  

PubMed

Tissue plasminogen activator (tPA) is the only available treatment for acute stroke. In addition to its vascular fibrinolytic action, tPA exerts various effects within the brain, ranging from synaptic plasticity to control of cell fate. To date, the influence of tPA in the ischemic brain has only been investigated on neuronal, microglial, and endothelial fate. We addressed the mechanism of action of tPA on oligodendrocyte (OL) survival and on the extent of white matter lesions in stroke. We also investigated the impact of aging on these processes. We observed that, in parallel to reduced levels of tPA in OLs, white matter gets more susceptible to ischemia in old mice. Interestingly, tPA protects murine and human OLs from apoptosis through an unexpected cytokine-like effect by the virtue of its epidermal growth factor-like domain. When injected into aged animals, tPA, although toxic to the gray matter, rescues white matter from ischemia independently of its proteolytic activity. These studies reveal a novel mechanism of action of tPA and unveil OL as a target cell for cytokine effects of tPA in brain diseases. They show overall that tPA protects white matter from stroke-induced lesions, an effect which may contribute to the global benefit of tPA-based stroke treatment. PMID:21576385

Correa, Fernando; Gauberti, Maxime; Parcq, Jérôme; Macrez, Richard; Hommet, Yannick; Obiang, Pauline; Hernangómez, Miriam; Montagne, Axel; Liot, Géraldine; Guaza, Carmen; Maubert, Eric; Ali, Carine; Vivien, Denis; Docagne, Fabian

2011-05-16

138

Pathways That Make Voices: White Matter Changes in Auditory Hallucinations  

Microsoft Academic Search

are one of the core symptoms of schizophrenia, is still a matter of debate. It has been hypothesized that alter- ations in connectivity between frontal and parietotempo- ralspeech-relatedareasmightcontributetothepathogen- esisofauditoryhallucinations.Thesenetworksareassumed tobecomedysfunctionalduringthegenerationandmoni- toring of inner speech. Magnetic resonance diffusion ten- sor imaging is a relatively new in vivo method to investi- gate the directionality of cortical white matter tracts. Objective:To investigate, using

Daniela Hubl; Thomas Koenig; Werner Strik; Andrea Federspiel; Roland Kreis; Chris Boesch; Stephan E. Maier; Gerhard Schroth; Karl Lovblad; Thomas Dierks

2004-01-01

139

Longitudinal changes in grey and white matter during adolescence  

Microsoft Academic Search

Brain development continues actively during adolescence. Previous MRI studies have shown complex patterns of apparent loss of grey matter (GM) volume and increases in white matter (WM) volume and fractional anisotropy (FA), an index of WM microstructure. In this longitudinal study (mean follow-up=2.5±0.5 years) of 24 adolescents, we used a voxel-based morphometry (VBM)-style analysis with conventional T1-weighted images to test

A. Giorgio; K. E. Watkins; M. Chadwick; S. James; L. Winmill; G. Douaud; N. De Stefano; P. M. Matthews; S. M. Smith; H. Johansen-Berg; A. C. James

2010-01-01

140

Normal-appearing white and grey matter damage in MS  

Microsoft Academic Search

\\u000a Abstract\\u000a   The aims of this study were to improve, using a 3.0 Tesla (T) scanner and diffusion tensor (DT) magnetic resonance imaging\\u000a (MRI) with sensitivity encoding, our understanding of: 1) the possible pathological substrates of normal-appearing white matter\\u000a (NAWM) and grey matter (GM) damage in multiple sclerosis (MS) and 2) the factors associated to WM and GM atrophy in this

Antonia Ceccarelli; Maria A. Rocca; Andrea Falini; Paola Tortorella; Elisabetta Pagani; Mariemma Rodegher; Giancarlo Comi; Giuseppe Scotti; Massimo Filippi

2007-01-01

141

Automatic segmentation of brain white matter and white matter lesions in normal aging: comparison of five multispectral techniques.  

PubMed

White matter loss, ventricular enlargement and white matter lesions are common findings on brain scans of older subjects. Accurate assessment of these different features is therefore essential for normal aging research. Recently, we developed a novel unsupervised classification method, named 'Multispectral Coloring Modulation and Variance Identification' (MCMxxxVI), that fuses two different structural magnetic resonance imaging (MRI) sequences in red/green color space and uses Minimum Variance Quantization (MVQ) as the clustering technique to segment different tissue types. Here we investigate how this method performs compared with several commonly used supervised image classifiers in segmenting normal-appearing white matter, white matter lesions and cerebrospinal fluid in the brains of 20 older subjects with a wide range of white matter lesion load and brain atrophy. The three tissue classes were segmented from T(1)-, T(2)-, T(2)?- and fluid attenuation inversion recovery (FLAIR)-weighted structural MRI data using MCMxxxVI and the four supervised multispectral classifiers available in the Analyze package, namely, Back-Propagated Neural Networks, Gaussian classifier, Nearest Neighbor and Parzen Windows. Bland-Altman analysis and Jaccard index values indicated that, in general, MCMxxxVI performed better than the supervised multispectral classifiers in identifying the three tissue classes, although final manual editing was still required to deliver radiologically acceptable results. These analyses show that MVQ, as implemented in MCMxxxVI, has the potential to provide quick and accurate white matter segmentations in the aging brain, although further methodological developments are still required to automate fully this technique. PMID:22071410

Valdés Hernández, Maria Del C; Gallacher, Peter J; Bastin, Mark E; Royle, Natalie A; Maniega, Susana Muñoz; Deary, Ian J; Wardlaw, Joanna M

2011-11-08

142

Higher diffusion in striatum and lower fractional anisotropy in white matter of methamphetamine users  

Microsoft Academic Search

Methamphetamine (METH) users showed structural and chemical abnormalities on magnetic resonance (MRI) studies, particularly in the frontal and basal ganglia brain regions. Diffusion tensor imaging (DTI) may provide further insights regarding the microstructural changes in METH users. We investigated diffusion tensor measures in frontal white matter and basal ganglia of 30 adult METH users and 30 control subjects using a

Daniel Alicata; Linda Chang; Christine Cloak; Kylie Abe; Thomas Ernst

2009-01-01

143

Correlation between Gray/White Matter Volume and Cognition in Healthy Elderly People  

ERIC Educational Resources Information Center

|This study applied volumetric analysis and voxel-based morphometry (VBM) of brain magnetic resonance (MR) images to assess whether correlations exist between global and regional gray/white matter volume and the cognitive functions of semantic memory and short-term memory, which are relatively well preserved with aging, using MR image data from…

Taki, Yasuyuki; Kinomura, Shigeo; Sato, Kazunori; Goto, Ryoi; Wu, Kai; Kawashima, Ryuta; Fukuda, Hiroshi

2011-01-01

144

In vivo investigation of white matter pathology in schizophrenia with magnetisation transfer imaging  

PubMed Central

OBJECTIVES—This study is the first to use magnetisation transfer imaging (MTI), a technique sensitive to myelin and axonal abnormalities, to investigate the white matter in vivo in patients with schizophrenia.?METHODS—MTI was performed in 25 schizophrenic patients and 30 healthy controls. A region of interest (ROI) approach was used to obtain magnetisation transfer ratios (MTRs) in several regions of cerebral white matter.?RESULTS—MTR values were significantly reduced in the right and left temporal regions in schizophrenic patients compared with controls (p<0.001). Clinical variables such as age, duration of symptoms, schizophrenic symptomatology, and soft neurological signs did not predict this reduction in MTR. There were no MTR abnormalities in the other regions sampled. However, the correlation between the left and right frontal MTR values was marginally significantly different in schizophrenic patients compared with controls suggesting that subtle differences in interhemispheric connections may be present.?CONCLUSIONS—Subtle white matter pathology, most likely related to myelin and axonal abnormalities, can be detected in the temporal lobes in schizophrenic patients. MTI may be a useful tool in investigating the white matter in schizophrenia.??

Foong, J; Maier, M; Barker, G; Brocklehurst, S; Miller, D; Ron, M

2000-01-01

145

White matter structures associated with creativity: Evidence from diffusion tensor imaging  

Microsoft Academic Search

Creativity has been essential to the development of human civilization and plays a crucial role in cultural life. However, despite literature that has proposed the importance of structural connectivity in the brain for creativity, the relationship between regional white matter integrity and creativity has never been directly investigated. In this study, we used diffusion tensor imaging and a behavioral creativity

Hikaru Takeuchi; Yasuyuki Taki; Yuko Sassa; Hiroshi Hashizume; Atsushi Sekiguchi; Ai Fukushima; Ryuta Kawashima

2010-01-01

146

Occult White Matter Damage Contributes to Intellectual Disability in Tuberous Sclerosis Complex  

ERIC Educational Resources Information Center

|Whether patients with tuberous sclerosis complex (TSC) have brain normal-appearing white matter (NAWM) damage and whether such damage contributes to their intellectual disability were examined in 15 TSC patients and 15 gender- and age-matched healthy controls using diffusion tensor imaging (DTI). Histogram and region of interest (ROI) analyses of…

Yu, Chunshui; Lin, Fuchun; Zhao, Li; Ye, Jing; Qin, Wen

2009-01-01

147

Abnormal Behaviors and Microstructural Changes in White Matter of Juvenile Mice Repeatedly Exposed to Amphetamine  

PubMed Central

Amphetamine (AMP) is an addictive CNS stimulant and has been commonly abused by adolescents and young adults, during which period brain white matter is still developing. This study was to examine the effect of a nonneurotoxic AMP on the white matter of juvenile mice. d-AMP (1.0?mg/kg) was given to young male C57BL/6 mice once a day for 21 days. The spatial working memory and locomotion of mice were measured at the end. Then, mice were sacrificed and their brains were processed for morphological analyses to examine the white matter structure and for Western blot analysis to measure three main proteins expressed in mature oligodendrocytes. AMP-treated mice displayed higher locomotion and spatial working memory impairment and showed lower levels of Nogo-A and GST-pi proteins in frontal cortex and lower MBP protein in the frontal cortex and hippocampus. They also had fewer mature oligodendrocytes and weak MBP immunofluorescent staining in the same two brain regions. But the striatum was spared. These results suggest that the late-developing white matter is vulnerable to AMP treatment which is able to increase striatal and cortical dopamine. Both the compromised white matter and increased dopamine may contribute to the observed behavioral changes in AMP-treated mice.

Yang, Hong-Ju; Wang, Lijun; Cheng, Qiang; Xu, Haiyun

2011-01-01

148

White matter integrity, language, and childhood onset schizophrenia  

PubMed Central

Background The heterogeneity of symptoms and cognitive deficits in schizophrenia can be explained by abnormal connectivity between brain regions. Childhood-onset schizophrenia (COS) is a particularly severe form of schizophrenia, with an onset during a key time period for both cerebral pruning and myelination. Methods Diffusion tensor images were acquired from 18 children and adolescents with COS and 25 controls. The COS group was divided into two sub-groups--one with linguistic impairment (LI) and the other without (NLI). The fractional anisotropy (FA), axial (AD), and radial diffusivity (RD) data from the two COS sub-groups were compared to each other and to the controls using tract-based spatial statistics (TBSS) analyses, which is a voxel-based method used to identify regions of white matter abnormalities. Results TBSS identified several regions in the left hemisphere where the LI group had increased AD and RD relative to the NLI and the control groups. These areas primarily localized to linguistic tracts: left superior longitudinal fasciculus and left inferior longitudinal fasciculus/inferior fronto-occipital fasciculus. Regions of increased RD overlapped regions of increased AD, with the former showing more pronounced effects. Conclusions Studies of adult-onset schizophrenia typically identify areas of higher RD but unchanged AD; however, normal development studies have shown that while RD decreases are pronounced over this age range, smaller decreases in AD can also be detected. The observed increases in both RD and AD suggest that developmental disturbances affecting the structural connectivity of these pathways are more severe in COS accompanied by severe linguistic impairments.

Clark, Kristi; Narr, Katherine L.; O'Neill, Joseph; Levitt, Jennifer; Siddarth, Prabha; Phillips, Owen; Toga, Arthur; Caplan, Rochelle

2012-01-01

149

Differential prefrontal white matter development in chimpanzees and humans.  

PubMed

A comparison of developmental patterns of white matter (WM) within the prefrontal region between humans and nonhuman primates is key to understanding human brain evolution. WM mediates complex cognitive processes and has reciprocal connections with posterior processing regions [1, 2]. Although the developmental pattern of prefrontal WM in macaques differs markedly from that in humans [3], this has not been explored in our closest evolutionary relative, the chimpanzee. The present longitudinal study of magnetic resonance imaging scans demonstrated that the prefrontal WM volume in chimpanzees was immature and had not reached the adult value during prepuberty, as observed in humans but not in macaques. However, the rate of prefrontal WM volume increase during infancy was slower in chimpanzees than in humans. These results suggest that a less mature and more protracted elaboration of neuronal connections in the prefrontal portion of the developing brain existed in the last common ancestor of chimpanzees and humans, and that this served to enhance the impact of postnatal experiences on neuronal connectivity. Furthermore, the rapid development of the human prefrontal WM during infancy may help the development of complex social interactions, as well as the acquisition of experience-dependent knowledge and skills to shape neuronal connectivity. PMID:21835623

Sakai, Tomoko; Mikami, Akichika; Tomonaga, Masaki; Matsui, Mie; Suzuki, Juri; Hamada, Yuzuru; Tanaka, Masayuki; Miyabe-Nishiwaki, Takako; Makishima, Haruyuki; Nakatsukasa, Masato; Matsuzawa, Tetsuro

2011-08-11

150

White Matter Volume Abnormalities and Associations with Symptomatology in Schizophrenia  

PubMed Central

The cerebral white matter (WM) is critically involved in many bio-behavioral functions impaired in schizophrenia. However, the specific neural systems underlying symptomatology in schizophrenia are not well known. By comparing the volume of all brain fiber systems between chronic patients with DSM-III-R schizophrenia (n = 88) and matched healthy community controls (n = 40), we found that a set of a priori WM regions of local and distal associative fiber systems were significantly different in patients with schizophrenia. There were significant positive correlations between volumes (larger) in anterior callosal, cingulate and temporal deep WM regions (related to distal connections) with positive symptoms, such as hallucinations, delusions and bizarre behavior, and significant negative correlation between volumes (smaller) in occipital and paralimbic superficial WM (related to local connections) and posterior callosal fiber systems with higher negative symptoms, such as alogia. Furthermore, the temporal sagittal system showed significant rightward asymmetry between patients and controls. These observations suggest a pattern of volume WM alterations associated with symptomatology in schizophrenia that may be related in part to predisposition to schizophrenia.

Makris, N.; Seidman, L. J.; Ahern, T.; Kennedy, D. N.; Caviness, V. S.; Tsuang, M. T.; Goldstein, J. M.

2010-01-01

151

Cognitive Intraindividual Variability and White Matter Integrity in Aging  

PubMed Central

The intraindividual variability (IIV) of cognitive performance has been shown to increase with aging. While brain research has generally focused on mean performance, little is known about neural correlates of cognitive IIV. Nevertheless, some studies suggest that IIV relates more strongly than mean level of performance to the quality of white matter (WM). Our study aims to explore the relation between WM integrity and cognitive IIV by combining functional (fMRI) and structural (diffusion tensor imaging, DTI) imaging. Twelve young adults (aged 18–30 years) and thirteen older adults (61–82 years) underwent a battery of neuropsychological tasks, along with fMRI and DTI imaging. Their behavioral data were analyzed and correlated with the imaging data at WM regions of interest defined on the basis of (1) the fMRI-activated areas and (2) the Johns Hopkins University (JHU) WM tractography atlas. For both methods, fractional anisotropy, along with the mean, radial, and axial diffusivity parameters, was computed. In accord with previous studies, our results showed that the DTI parameters were more related to IIV than to mean performance. Results also indicated that age differences in the DTI parameters were more pronounced in the regions activated primarily by young adults during a choice reaction-time task than in those also activated in older adults.

2013-01-01

152

SCIENCE MATTERS (White) Hooded Sweatshirt (Size: XX Large)  

NSDL National Science Digital Library

White, heavy duty 9.3 oz. 50/50 blend, double-lined hood and pockets. Sweatshirt is printed with Science Matters logo on front and NSTA logo on back. Available in Adult sizes: Small, Medium, Large, X Large, XX Large.

1900-01-01

153

Neurocognitive Correlates of White Matter Quality in Adolescent Substance Users  

ERIC Educational Resources Information Center

|Background: Progressive myelination during adolescence implicates an increased vulnerability to neurotoxic substances and enduring neurocognitive consequences. This study examined the cognitive manifestations of altered white matter microstructure in chronic marijuana and alcohol-using (MJ + ALC) adolescents. Methods: Thirty-six MJ + ALC…

Bava, Sunita; Jacobus, Joanna; Mahmood, Omar; Yang, Tony T.; Tapert, Susan F.

2010-01-01

154

White Matter Damage and Cognitive Impairment after Traumatic Brain Injury  

ERIC Educational Resources Information Center

|White matter disruption is an important determinant of cognitive impairment after brain injury, but conventional neuroimaging underestimates its extent. In contrast, diffusion tensor imaging provides a validated and sensitive way of identifying the impact of axonal injury. The relationship between cognitive impairment after traumatic brain injury…

Kinnunen, Kirsi Maria; Greenwood, Richard; Powell, Jane Hilary; Leech, Robert; Hawkins, Peter Charlie; Bonnelle, Valerie; Patel, Maneesh Chandrakant; Counsell, Serena Jane; Sharp, David James

2011-01-01

155

SCIENCE MATTERS (White) Hooded Sweatshirt (Size: X Large)  

NSDL National Science Digital Library

White, heavy duty 9.3 oz. 50/50 blend, double-lined hood and pockets. Sweatshirt is printed with Science Matters logo on front and NSTA logo on back. Available in Adult sizes: Small, Medium, Large, X Large, XX Large.

1900-01-01

156

White Matter Structure Changes as Adults Learn a Second Language  

Microsoft Academic Search

Traditional models hold that the plastic reorganization of brain structures occurs mainly during childhood and adolescence, leaving adults with limited means to learn new knowledge and skills. Research within the last decade has begun to overturn this belief, documenting changes in the brain's gray and white matter as healthy adults learn simple motor and cognitive skills [Lövdén, M., Bodammer, N.

Alexander A. Schlegel; Justin J. Rudelson; Peter U. Tse

157

Connecting Cerebral White Matter Lesions and Hypertensive Target Organ Damage  

PubMed Central

Chronic hypertension leads to concomitant remodeling of the cardiac and vascular systems and various organs, especially the brain, kidney, and retina. The brain is an early target of organ damage due to high blood pressure, which is the major modifiable risk factor for stroke and small vessel disease. Stroke is the second leading cause of death and the number one cause of disability worldwide and over 80% of strokes occur in the elderly. Preclinical hypertensive lesions in most target organs are clearly identified: left ventricular hypertrophy for the heart, microalbuminuria for the kidney, fundus abnormalities for the eye, and intima-media thickness and pulse wave velocity for the vessels. However, early hypertensive brain damage is not fully studied due to difficulties in access and the expense of techniques. After age, hypertension is the most-important risk factor for cerebral white matter lesions, which are an important prognostic factor for stroke, cognitive impairment, dementia, and death. Studies have shown an association between white matter lesions and a number of extracranial systems affected by high BP and also suggest that correct antihypertensive treatment could slow white matter lesions progression. There is strong evidence that cerebral white matter lesions in hypertensive patients should be considered a silent early marker of brain damage.

Sierra, Cristina; Lopez-Soto, Alfons; Coca, Antonio

2011-01-01

158

White Matter Structure Changes as Adults Learn a Second Language  

Microsoft Academic Search

Traditional models hold that the plastic reorganization of brain structures occurs mainly during childhood and adolescence, leaving adults with limited means to learn new knowledge and skills. Research within the last decade has begun to overturn this belief, documenting changes in the brain's gray and white matter as healthy adults learn simple motor and cognitive skills [Lövdén, M., Bodammer, N.

Alexander A. Schlegel; Justin J. Rudelson; Peter U. Tse

2012-01-01

159

Interparietal white matter development predicts numerical performance in young children  

Microsoft Academic Search

In an effort to understand the role of interhemispheric transfer in numerical development, we investigated the relationship between children's developing knowledge of numbers and the integrity of their white matter connections between the cerebral hemispheres (the corpus callosum). We used diffusion tensor imaging (DTI) tractography analyses to test the link between the development of the corpus callosum and performance on

Jessica F. Cantlon; Simon W. Davis; Melissa E. Libertus; Jill Kahane; Elizabeth M. Brannon; Kevin A. Pelphrey

2011-01-01

160

Contrast between white and grey matter: MRI appearance with ageing  

Microsoft Academic Search

MRI contrast between white and grey matter appears to be higher in young normal subjects than in older patients. The aim of the present study was to investigate the possible relationships between these changes in contrast and ageing. It consisted of two parts. In the first part we retrospectively evaluated 140 MRI brain examinations of healthy subjects, 20 per decade

S. Magnaldi; M. Ukmar; A. Vasciaveo; R. Longo; R. S. Pozzi-Mucelli

1993-01-01

161

Body mass and white matter integrity: the influence of vascular and inflammatory markers.  

PubMed

High adiposity is deleteriously associated with brain health, and may disproportionately affect white matter integrity; however, limited information exists regarding the mechanisms underlying the association between body mass (BMI) and white matter integrity. The present study evaluated whether vascular and inflammatory markers influence the relationship between BMI and white matter in healthy aging. We conducted a cross-sectional evaluation of white matter integrity, BMI, and vascular/inflammatory factors in a cohort of 138 healthy older adults (mean age: 71.3 years). Participants underwent diffusion tensor imaging, provided blood samples, and participated in a health evaluation. Vascular risk factors and vascular/inflammatory blood markers were assessed. The primary outcome measure was fractional anisotropy (FA) of the genu, body, and splenium (corpus callosum); exploratory measures included additional white matter regions, based on significant associations with BMI. Regression analyses indicated that higher BMI was associated with lower FA in the corpus callosum, cingulate, and fornix (p<.001). Vascular and inflammatory factors influenced the association between BMI and FA. Specifically, BMI was independently associated with the genu [?=-.21; B=-.0024; 95% CI, -.0048 to -.0000; p=.05] and cingulate fibers [?=-.39; B=-.0035; 95% CI,-.0056 to -.0015; p<.001], even after controlling for vascular/inflammatory risk factors and blood markers. In contrast, BMI was no longer significantly associated with the fornix and middle/posterior regions of the corpus callosum after controlling for these markers. Results partially support a vascular/inflammatory hypothesis, but also suggest a more complex relationship between BMI and white matter characterized by potentially different neuroanatomic vulnerability. PMID:24147070

Bettcher, Brianne Magouirk; Walsh, Christine M; Watson, Christa; Miller, Joshua W; Green, Ralph; Patel, Nihar; Miller, Bruce L; Neuhaus, John; Yaffe, Kristine; Kramer, Joel H

2013-10-16

162

Body Mass and White Matter Integrity: The Influence of Vascular and Inflammatory Markers  

PubMed Central

High adiposity is deleteriously associated with brain health, and may disproportionately affect white matter integrity; however, limited information exists regarding the mechanisms underlying the association between body mass (BMI) and white matter integrity. The present study evaluated whether vascular and inflammatory markers influence the relationship between BMI and white matter in healthy aging. We conducted a cross-sectional evaluation of white matter integrity, BMI, and vascular/inflammatory factors in a cohort of 138 healthy older adults (mean age: 71.3 years). Participants underwent diffusion tensor imaging, provided blood samples, and participated in a health evaluation. Vascular risk factors and vascular/inflammatory blood markers were assessed. The primary outcome measure was fractional anisotropy (FA) of the genu, body, and splenium (corpus callosum); exploratory measures included additional white matter regions, based on significant associations with BMI. Regression analyses indicated that higher BMI was associated with lower FA in the corpus callosum, cingulate, and fornix (p<.001). Vascular and inflammatory factors influenced the association between BMI and FA. Specifically, BMI was independently associated with the genu [?=-.21; B=-.0024; 95% CI, -.0048 to -.0000; p=.05] and cingulate fibers [?=-.39; B=-.0035; 95% CI,-.0056 to -.0015; p<.001], even after controlling for vascular/inflammatory risk factors and blood markers. In contrast, BMI was no longer significantly associated with the fornix and middle/posterior regions of the corpus callosum after controlling for these markers. Results partially support a vascular/inflammatory hypothesis, but also suggest a more complex relationship between BMI and white matter characterized by potentially different neuroanatomic vulnerability.

Bettcher, Brianne Magouirk; Walsh, Christine M.; Watson, Christa; Miller, Joshua W.; Green, Ralph; Patel, Nihar; Miller, Bruce L.; Neuhaus, John; Yaffe, Kristine; Kramer, Joel H.

2013-01-01

163

Improved sensitivity to cerebral white matter abnormalities in Alzheimer's disease with spherical deconvolution based tractography.  

PubMed

Diffusion tensor imaging (DTI) based fiber tractography (FT) is the most popular approach for investigating white matter tracts in vivo, despite its inability to reconstruct fiber pathways in regions with "crossing fibers." Recently, constrained spherical deconvolution (CSD) has been developed to mitigate the adverse effects of "crossing fibers" on DTI based FT. Notwithstanding the methodological benefit, the clinical relevance of CSD based FT for the assessment of white matter abnormalities remains unclear. In this work, we evaluated the applicability of a hybrid framework, in which CSD based FT is combined with conventional DTI metrics to assess white matter abnormalities in 25 patients with early Alzheimer's disease. Both CSD and DTI based FT were used to reconstruct two white matter tracts: one with regions of "crossing fibers," i.e., the superior longitudinal fasciculus (SLF) and one which contains only one fiber orientation, i.e. the midsagittal section of the corpus callosum (CC). The DTI metrics, fractional anisotropy (FA) and mean diffusivity (MD), obtained from these tracts were related to memory function. Our results show that in the tract with "crossing fibers" the relation between FA/MD and memory was stronger with CSD than with DTI based FT. By contrast, in the fiber bundle where one fiber population predominates, the relation between FA/MD and memory was comparable between both tractography methods. Importantly, these associations were most pronounced after adjustment for the planar diffusion coefficient, a measure reflecting the degree of fiber organization complexity. These findings indicate that compared to conventionally applied DTI based FT, CSD based FT combined with DTI metrics can increase the sensitivity to detect functionally significant white matter abnormalities in tracts with complex white matter architecture. PMID:22952880

Reijmer, Yael D; Leemans, Alexander; Heringa, Sophie M; Wielaard, Ilse; Jeurissen, Ben; Koek, Huiberdina L; Biessels, Geert Jan

2012-08-31

164

The D-allele of ACE insertion\\/deletion polymorphism is associated with regional white matter volume changes and cognitive impairment in remitted geriatric depression  

Microsoft Academic Search

Prior studies suggested that angiotensin-converting enzyme (ACE) affected vascular homeostasis and degradation of amyloid ? (A?). It is associated with the therapeutic outcome in major depression. The aim of this study was to investigate the association between angiotensin-converting enzyme (ACE) insertion\\/deletion (I\\/D) polymorphism and structural abnormalities in remitted geriatric depression (RGD), and test the relationship of neuropsychological performances and regional

Zhenghua Hou; Yonggui Yuan; Zhijun Zhang; Gang Hou; Jiayong You; Feng Bai

2010-01-01

165

Aerobic fitness is associated with gray matter volume and white matter integrity in multiple sclerosis  

Microsoft Academic Search

Alterations in gray and white matter have been well documented in individuals with multiple sclerosis. Severity and extent of such brain tissue damage have been associated with cognitive impairment, disease duration and neurological disability, making quantitative indices of tissue damage important markers of disease progression. In this study, we investigated the association between cardiorespiratory fitness and measures of gray matter

Ruchika Shaurya Prakash; Erin M. Snook; Robert W. Motl; Arthur F. Kramer

2010-01-01

166

Susceptibility induced gray-white matter MRI contrast in the human brain.  

PubMed

MR phase images have shown significantly improved contrast between cortical gray and white matter regions compared to magnitude images obtained with gradient echo sequences. A variety of underlying biophysical mechanisms (including iron, blood, myelin content, macromolecular chemical exchange, and fiber orientation) have been suggested to account for this observation but assessing the individual contribution of these factors is limited in vivo. For a closer investigation of iron and myelin induced susceptibility changes, postmortem MRI of six human corpses (age range at death: 56-80 years) was acquired in situ. Following autopsy, the iron concentrations in the frontal and occipital cortex as well as in white matter regions were chemically determined. The magnetization transfer ratio (MTR) was used as an indirect measure for myelin content. Susceptibility effects were assessed separately by determining R2* relaxation rates and quantitative phase shifts. Contributions of myelin and iron to local variations of the susceptibility were assessed by univariate and multivariate linear regression analysis. Mean iron concentration was lower in the frontal cortex than in frontal white matter (26 ± 6 vs. 45 ± 6 mg/kg wet tissue) while an inverse relation was found in the occipital lobe (cortical gray matter: 41 ± 10 vs. white matter: 34 ± 10mg/kg wet tissue). Multiple regression analysis revealed iron and MTR as independent predictors of the effective transverse relaxation rate R2 but solely MTR was identified as source of MR phase contrast. R2 was correlated with iron concentrations in cortical gray matter only (r=0.42, p<0.05). In conclusion, MR phase contrast between cortical gray and white matter can be mainly attributed to variations in myelin content, but not to iron concentration. Both, myelin and iron impact the effective transverse relaxation rate R2 significantly. Magnitude contrast is limited because it only reflects the extent but not the direction of the susceptibility shift. PMID:21893208

Langkammer, Christian; Krebs, Nikolaus; Goessler, Walter; Scheurer, Eva; Yen, Kathrin; Fazekas, Franz; Ropele, Stefan

2011-08-26

167

Susceptibility induced gray-white matter MRI contrast in the human brain  

PubMed Central

MR phase images have shown significantly improved contrast between cortical gray and white matter regions compared to magnitude images obtained with gradient echo sequences. A variety of underlying biophysical mechanisms (including iron, blood, myelin content, macromolecular chemical exchange, and fiber orientation) have been suggested to account for this observation but assessing the individual contribution of these factors is limited in vivo. For a closer investigation of iron and myelin induced susceptibility changes, postmortem MRI of six human corpses (age range at death: 56–80 years) was acquired in situ. Following autopsy, the iron concentrations in the frontal and occipital cortex as well as in white matter regions were chemically determined. The magnetization transfer ratio (MTR) was used as an indirect measure for myelin content. Susceptibility effects were assessed separately by determining R2* relaxation rates and quantitative phase shifts. Contributions of myelin and iron to local variations of the susceptibility were assessed by univariate and multivariate linear regression analysis. Mean iron concentration was lower in the frontal cortex than in frontal white matter (26 ± 6 vs. 45 ± 6 mg/kg wet tissue) while an inverse relation was found in the occipital lobe (cortical gray matter: 41 ± 10 vs. white matter: 34 ± 10 mg/kg wet tissue). Multiple regression analysis revealed iron and MTR as independent predictors of the effective transverse relaxation rate R2* but solely MTR was identified as source of MR phase contrast. R2* was correlated with iron concentrations in cortical gray matter only (r = 0.42, p < 0.05). In conclusion, MR phase contrast between cortical gray and white matter can be mainly attributed to variations in myelin content, but not to iron concentration. Both, myelin and iron impact the effective transverse relaxation rate R2* significantly. Magnitude contrast is limited because it only reflects the extent but not the direction of the susceptibility shift.

Langkammer, Christian; Krebs, Nikolaus; Goessler, Walter; Scheurer, Eva; Yen, Kathrin; Fazekas, Franz; Ropele, Stefan

2012-01-01

168

Gray and white matter water diffusion in the syndromic variants of frontotemporal dementia  

PubMed Central

Objective: To use diffusion tensor imaging (DTI) to assess gray matter and white matter tract diffusion in behavioral variant frontotemporal dementia (bvFTD), semantic dementia (SMD), and progressive nonfluent aphasia (PNFA). Methods: This was a case-control study where 16 subjects with bvFTD, 7 with PNFA, and 4 with SMD were identified and matched by age and gender to 19 controls. All subjects had 3-T head MRI with a DTI sequence with diffusion encoding in 21 directions. Gray matter mean diffusivity (MD) was assessed using a region-of-interest (ROI) and voxel-level approach, and voxel-based morphometry was used to assess patterns of gray matter loss. White matter tract diffusivity (fractional anisotropy and radial diffusivity) was assessed by placing ROIs on tracts of interest. Results: In bvFTD, increased gray matter MD and gray matter loss were identified bilaterally throughout frontal and temporal lobes, with abnormal diffusivity observed in white matter tracts that connect to these regions. In SMD, gray matter loss and increased MD were identified predominantly in the left temporal lobe, with tract abnormalities observed in the inferior longitudinal fasciculus and uncinate fasciculus. In PNFA, gray matter loss and increased MD were observed in left inferior frontal lobe, insula, and supplemental motor area, with tract abnormalities observed in the superior longitudinal fasciculus. Conclusions: The diffusivity of gray matter is increased in regions that are atrophic in frontotemporal dementia, suggesting disruption of the cytoarchitecture of remaining tissue. Furthermore, damage was identified in white matter tracts that interconnect these regions, supporting the hypothesis that these diseases involve different and specific brain networks. GLOSSARY AAL = automated anatomic labeling; AC = anterior cingulate; ADRC = Alzheimer's Disease Research Center; ADPR = Alzheimer's Disease Patient Registry; AOS = apraxia of speech; bvFTD = behavioral variant frontotemporal dementia; CV = coefficient of variation; DA = axial diffusivity; DR = radial diffusivity; DTI = diffusion tensor imaging; FA = fractional anisotropy; FDR = false discovery rate; FOV = field of view; FTD = frontotemporal dementia; FWHM = full-width at half-maximum; GCC = genu of the corpus callosum; HDW = high-dimensional warping; ILF = inferior longitudinal fasciculus; MD = mean diffusivity; MPRAGE = magnetization prepared rapid acquisition gradient echo; PC = posterior cingulate; PNFA = progressive nonfluent aphasia; PVC = partial volume correction; ROI = region of interest; SLF = superior longitudinal fasciculus; SMD = semantic dementia; UNC = uncinate fasciculus.

Whitwell, J.L.; Avula, R.; Senjem, M.L.; Kantarci, K.; Weigand, S.D.; Samikoglu, A.; Edmonson, H.A.; Vemuri, P.; Knopman, D.S.; Boeve, B.F.; Petersen, R.C.; Josephs, K.A.; Jack, C.R.

2010-01-01

169

Early Gray-Matter and White-Matter Concentration in Infancy Predict Later Language Skills: A Whole Brain Voxel-Based Morphometry Study  

ERIC Educational Resources Information Center

|Magnetic Resonance Imaging (MRI) brain scans were obtained from 19 infants at 7 months. Expressive and receptive language performance was assessed at 12 months. Voxel-based morphometry (VBM) identified brain regions where gray-matter and white-matter concentrations at 7 months correlated significantly with children's language scores at 12 months.…

Can, Dilara Deniz; Richards, Todd; Kuhl, Patricia K.

2013-01-01

170

Gray and White Matter Distribution in Dyslexia: A VBM Study of Superior Temporal Gyrus Asymmetry.  

PubMed

In the present study, we investigated brain morphological signatures of dyslexia by using a voxel-based asymmetry analysis. Dyslexia is a developmental disorder that affects the acquisition of reading and spelling abilities and is associated with a phonological deficit. Speech perception disabilities have been associated with this deficit, particularly when listening conditions are challenging, such as in noisy environments. These deficits are associated with known neurophysiological correlates, such as a reduction in the functional activation or a modification of functional asymmetry in the cortical regions involved in speech processing, such as the bilateral superior temporal areas. These functional deficits have been associated with macroscopic morphological abnormalities, which potentially include a reduction in gray and white matter volumes, combined with modifications of the leftward asymmetry along the perisylvian areas. The purpose of this study was to investigate gray/white matter distribution asymmetries in dyslexic adults using automated image processing derived from the voxel-based morphometry technique. Correlations with speech-in-noise perception abilities were also investigated. The results confirmed the presence of gray matter distribution abnormalities in the superior temporal gyrus (STG) and the superior temporal Sulcus (STS) in individuals with dyslexia. Specifically, the gray matter of adults with dyslexia was symmetrically distributed over one particular region of the STS, the temporal voice area, whereas normal readers showed a clear rightward gray matter asymmetry in this area. We also identified a region in the left posterior STG in which the white matter distribution asymmetry was correlated to speech-in-noise comprehension abilities in dyslexic adults. These results provide further information concerning the morphological alterations observed in dyslexia, revealing the presence of both gray and white matter distribution anomalies and the potential involvement of these defects in speech-in-noise deficits. PMID:24098565

Dole, Marjorie; Meunier, Fanny; Hoen, Michel

2013-10-01

171

Gray and White Matter Distribution in Dyslexia: A VBM Study of Superior Temporal Gyrus Asymmetry  

PubMed Central

In the present study, we investigated brain morphological signatures of dyslexia by using a voxel-based asymmetry analysis. Dyslexia is a developmental disorder that affects the acquisition of reading and spelling abilities and is associated with a phonological deficit. Speech perception disabilities have been associated with this deficit, particularly when listening conditions are challenging, such as in noisy environments. These deficits are associated with known neurophysiological correlates, such as a reduction in the functional activation or a modification of functional asymmetry in the cortical regions involved in speech processing, such as the bilateral superior temporal areas. These functional deficits have been associated with macroscopic morphological abnormalities, which potentially include a reduction in gray and white matter volumes, combined with modifications of the leftward asymmetry along the perisylvian areas. The purpose of this study was to investigate gray/white matter distribution asymmetries in dyslexic adults using automated image processing derived from the voxel-based morphometry technique. Correlations with speech-in-noise perception abilities were also investigated. The results confirmed the presence of gray matter distribution abnormalities in the superior temporal gyrus (STG) and the superior temporal Sulcus (STS) in individuals with dyslexia. Specifically, the gray matter of adults with dyslexia was symmetrically distributed over one particular region of the STS, the temporal voice area, whereas normal readers showed a clear rightward gray matter asymmetry in this area. We also identified a region in the left posterior STG in which the white matter distribution asymmetry was correlated to speech-in-noise comprehension abilities in dyslexic adults. These results provide further information concerning the morphological alterations observed in dyslexia, revealing the presence of both gray and white matter distribution anomalies and the potential involvement of these defects in speech-in-noise deficits.

Dole, Marjorie; Meunier, Fanny; Hoen, Michel

2013-01-01

172

Incident lacunes preferentially localize to the edge of white matter hyperintensities: insights into the pathophysiology of cerebral small vessel disease.  

PubMed

White matter hyperintensities and lacunes are among the most frequent abnormalities on brain magnetic resonance imaging. They are commonly related to cerebral small vessel disease and associated with both stroke and dementia. We examined the spatial relationships between incident lacunes and white matter hyperintensities and related these findings to information on vascular anatomy to study possible mechanistic links between the two lesion types. Two hundred and seventy-six patients with cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL), a genetically defined small vessel disease with mutations in the NOTCH3 gene were followed with magnetic resonance imaging over a total of 633 patient years. Using difference images and Jacobian maps from registered images we identified 104 incident lacunes. The majority (n = 95; 91.3%) of lacunes developed at the edge of a white matter hyperintensity whereas few lacunes were found to develop fully within (n = 6; 5.8%) or outside (n = 3; 2.9%) white matter hyperintensities. Adding information on vascular anatomy revealed that the majority of incident lacunes developed proximal to a white matter hyperintensity along the course of perforating vessels supplying the respective brain region. We further studied the spatial relationship between prevalent lacunes and white matter hyperintensities both in 365 patients with CADASIL and in 588 elderly subjects from the Austrian Stroke Prevention Study. The results were consistent with the results for incident lacunes. Lesion prevalence maps in different disease stages showed a spread of lesions towards subcortical regions in both cohorts. Our findings suggest that the mechanisms of lacunes and white matter hyperintensities are intimately connected and identify the edge of white matter hyperintensities as a predilection site for lacunes. Our observations further support and refine the concept of the white matter hyperintensity penumbra. PMID:23864274

Duering, Marco; Csanadi, Endy; Gesierich, Benno; Jouvent, Eric; Hervé, Dominique; Seiler, Stephan; Belaroussi, Boubakeur; Ropele, Stefan; Schmidt, Reinhold; Chabriat, Hugues; Dichgans, Martin

2013-07-17

173

Automated localization of periventricular and subcortical white matter lesions  

NASA Astrophysics Data System (ADS)

It is still unclear whether periventricular and subcortical white matter lesions (WMLs) differ in etiology or clinical consequences. Studies addressing this issue would benefit from automated segmentation and localization of WMLs. Several papers have been published on WML segmentation in MR images. Automated localization however, has not been investigated as much. This work presents and evaluates a novel method to label segmented WMLs as periventricular and subcortical. The proposed technique combines tissue classification and registration-based segmentation to outline the ventricles in MRI brain data. The segmented lesions can then be labeled into periventricular WMLs and subcortical WMLs by applying region growing and morphological operations. The technique was tested on scans of 20 elderly subjects in which neuro-anatomy experts manually segmented WMLs. Localization accuracy was evaluated by comparing the results of the automated method with a manual localization. Similarity indices and volumetric intraclass correlations between the automated and the manual localization were 0.89 and 0.95 for periventricular WMLs and 0.64 and 0.89 for subcortical WMLs, respectively. We conclude that this automated method for WML localization performs well to excellent in comparison to the gold standard.

van der Lijn, Fedde; Vernooij, Meike W.; Ikram, M. Arfan; Vrooman, Henri A.; Rueckert, Daniel; Hammers, Alexander; Breteler, Monique M. B.; Niessen, Wiro J.

2007-03-01

174

Lifelong bilingualism maintains white matter integrity in older adults.  

PubMed

Previous research has shown that bilingual speakers have higher levels of cognitive control than comparable monolinguals, especially at older ages. The present study investigates a possible neural correlate of this behavioral effect. Given that white matter (WM) integrity decreases with age in adulthood, we tested the hypothesis that bilingualism is associated with maintenance of WM in older people. Using diffusion tensor imaging, we found higher WM integrity in older people who were lifelong bilinguals than in monolinguals. This maintained integrity was measured by fractional anisotropy (FA) and was found in the corpus callosum extending to the superior and inferior longitudinal fasciculi. We also hypothesized that stronger WM connections would be associated with more widely distributed patterns of functional connectivity in bilinguals. We tested this by assessing the resting-state functional connectivity of frontal lobe regions adjacent to WM areas with group differences in FA. Bilinguals showed stronger anterior to posterior functional connectivity compared to monolinguals. These results are the first evidence that maintained WM integrity is related to lifelong naturally occurring experience; the resulting enhanced structural and functional connectivity may provide a neural basis for "brain reserve." PMID:22090506

Luk, Gigi; Bialystok, Ellen; Craik, Fergus I M; Grady, Cheryl L

2011-11-16

175

Lifelong Bilingualism Maintains White Matter Integrity in Older Adults  

PubMed Central

Previous research has shown that bilingual speakers have higher levels of cognitive control than comparable monolinguals, especially at older ages. The present study investigates a possible neural correlate of this behavioral effect. Given that white matter (WM) integrity decreases with age in adulthood, we tested the hypothesis that bilingualism is associated with maintenance of WM in older people. Using diffusion tensor imaging, we found higher WM integrity in older people who were lifelong bilinguals than in monolinguals. This maintained integrity was measured by fractional anisotropy (FA) and was found in the corpus callosum extending to the superior and inferior longitudinal fasciculi. We also hypothesized that stronger WM connections would be associated with more widely distributed patterns of functional connectivity in bilinguals. We tested this by assessing the resting-state functional connectivity of frontal lobe regions adjacent to WM areas with group differences in FA. Bilinguals showed stronger anterior to posterior functional connectivity compared to monolinguals. These results are the first evidence that maintained WM integrity is related to lifelong naturally occurring experience; the resulting enhanced structural and functional connectivity may provide a neural basis for “brain reserve.”

Luk, Gigi; Bialystok, Ellen; Craik, Fergus I. M.; Grady, Cheryl L.

2012-01-01

176

Adolescent Toluene Inhalation in Rats Affects White Matter Maturation with the Potential for Recovery Following Abstinence  

PubMed Central

Inhalant misuse is common during adolescence, with ongoing chronic misuse associated with neurobiological and cognitive abnormalities. While human imaging studies consistently report white matter abnormalities among long-term inhalant users, longitudinal studies have been lacking with limited data available regarding the progressive nature of such abnormalities, including the potential for recovery following periods of sustained abstinence. We exposed adolescent male Wistar rats (postnatal day 27) to chronic intermittent inhaled toluene (3,000 ppm) for 1 hour/day, 3 times/week for 8 weeks to model abuse patterns observed in adolescent and young adult human users. This dosing regimen resulted in a significant retardation in weight gain during the exposure period (p<0.05). In parallel, we performed longitudinal magnetic resonance imaging (T2-weighted) and diffusion tensor imaging prior to exposure, and after 4 and 8 weeks, to examine the integrity of white matter tracts, including the anterior commissure and corpus callosum. We also conducted imaging after 8 weeks of abstinence to assess for potential recovery. Chronic intermittent toluene exposure during adolescence and early adulthood resulted in white matter abnormalities, including a decrease in axial (p<0.05) and radial (p<0.05) diffusivity. These abnormalities appeared region-specific, occurring in the anterior commissure but not the corpus callosum and were not present until after at least 4 weeks of exposure. Toluene-induced effects on both body weight and white matter parameters recovered following abstinence. Behaviourally, we observed a progressive decrease in rearing activity following toluene exposure but no difference in motor function, suggesting cognitive function may be more sensitive to the effects of toluene. Furthermore, deficits in rearing were present by 4 weeks suggesting that toluene may affect behaviour prior to detectable white matter abnormalities. Consequently, exposure to inhalants that contain toluene during adolescence and early adulthood appear to differentially affect white matter maturation and behavioural outcomes, although recovery can occur following abstinence.

Egan, Gary; Kolbe, Scott; Gavrilescu, Maria; Wright, David; Lubman, Dan Ian; Lawrence, Andrew John

2012-01-01

177

Measuring in vivo myelination of human white matter fiber tracts with magnetization transfer MR.  

PubMed

Precise characterization of white matter pathways is important for the understanding of structural-functional relationships in the human brain. While it is known from postmortem studies that the connectivity of cortical areas is conveyed by projection, commissural, and association fibers, most clinical studies disregard useful information about specific fiber tracts. Magnetization transfer (MT) MR detects the relative proportion of free mobile protons and immobile protons bound to macromolecules. MT values correlate with histopathology and it has been proposed that in the white matter, the amount of magnetization transfer correlates with the degree of myelination. Thus, MT-MR provides measures that may reflect more accurately the physiology and natural course of diseases involving the white matter. We applied this quantitative in vivo method to five children at different ages to determine whether the maturational changes of distinct fiber tracts could be measured. All regions of interest were localized by means of Brodmann's original descriptions and the additional use of reconstructed 3D-matched data from 10 myelin-stained human brain specimens. With this atlas-guided approach we localized and measured 26 supratentorial white matter fiber tracts in each hemisphere, connecting to primary as well as association cortices. All fiber tracts showed consistent age-related MT changes and the strongest effects were found in those tracts projecting to the primary cortical areas. These results suggest that our method is suitable for in vivo MT measurements in specific fiber tracts. It can provide data that relate to myelination during ontogenesis or myelination delays in myelin disorders. In the clinical domain, the focus on specific fiber tracts appears to be advantageous over standard approaches, because such system of parcellation is based on the functional anatomy of the white matter. Consequently, it may be especially useful for topical analysis in neurology allowing the assessment of the functional consequences of white matter damage as well as the effectiveness of treatments in patients with any lesion that can be visualized by MRI. PMID:10191168

Rademacher, J; Engelbrecht, V; Bürgel, U; Freund, H; Zilles, K

1999-04-01

178

Effects of aging and calorie restriction on white matter in rhesus macaques.  

PubMed

Rhesus macaques on a calorie restricted diet (CR) develop less age-related disease, have virtually no indication of diabetes, are protected against sarcopenia, and potentially live longer. Beneficial effects of caloric restriction likely include reductions in age-related inflammation and oxidative damage. Oligodendrocytes are particularly susceptible to inflammation and oxidative stress, therefore, we hypothesized that CR would have a beneficial effect on brain white matter and would attenuate age-related decline in this tissue. CR monkeys and controls underwent diffusion tensor imaging (DTI). A beneficial effect of CR indexed by DTI was observed in superior longitudinal fasciculus, fronto-occipital fasciculus, external capsule, and brainstem. Aging effects were observed in several regions, although CR appeared to attenuate age-related alterations in superior longitudinal fasciculus, frontal white matter, external capsule, right parahippocampal white matter, and dorsal occipital bundle. The results, however, were regionally specific and also suggested that CR is not salutary across all white matter. Further evaluation of this unique cohort of elderly primates to mortality will shed light on the ultimate benefits of an adult-onset, moderate CR diet for deferring brain aging. PMID:20541839

Bendlin, B B; Canu, E; Willette, A; Kastman, E K; McLaren, D G; Kosmatka, K J; Xu, G; Field, A S; Colman, R J; Coe, C L; Weindruch, R H; Alexander, A L; Johnson, S C

2010-06-11

179

Gender differences in the relationship between white matter organization and adolescent substance use disorders  

PubMed Central

Few studies have focused on the neurobiological correlates of adolescent-onset substance use disorders (SUDs), particularly with respect to white matter development and organization. This study investigated microstructural white matter characteristics associated with SUDs during the adolescent developmental period. Twenty-four case adolescents (ages 14-18) entering treatment for SUDs and 12 sex- and age-matched control adolescents with no psychopathology were compared. Diffusion tensor imaging data were collected and analyzed using the whole brain, tract-based spatial statistics (TBSS) method. In order to comprehensively characterize diffusivity characteristics, we first studied fractional anisotropy (FA), and within regions that differed in FA, other indicators of microstructure, including the axial diffusivity (AD), radial diffusivity (RD), and mean diffusivity (MD). A large cluster of significantly lower FA values was found in cases compared to controls in the superior longitudinal fasciculus (SLF). Within this cluster, AD and RD were also significantly different between the groups, while MD was not significantly different. For FA, a significant group by sex interaction was found; females with SUD exhibited lower FA than males with SUD, while control females exhibited higher FA than control males. These results indicated significantly lower white matter integrity in the superior longitudinal fasciculus region of association cortex, and assessed using multiple indicators of diffusion. These findings suggest that the disruption of normal white matter development due to substance exposure may be more severe in females than in males.

Thatcher, Dawn L.; Pajtek, Stefan; Chung, Tammy; Terwilliger, Robert A.; Clark, Duncan B.

2011-01-01

180

Developmental Patterns of Doublecortin Expression and White Matter Neuron Density in the Postnatal Primate Prefrontal Cortex and Schizophrenia  

PubMed Central

Postnatal neurogenesis occurs in the subventricular zone and dentate gyrus, and evidence suggests that new neurons may be present in additional regions of the mature primate brain, including the prefrontal cortex (PFC). Addition of new neurons to the PFC implies local generation of neurons or migration from areas such as the subventricular zone. We examined the putative contribution of new, migrating neurons to postnatal cortical development by determining the density of neurons in white matter subjacent to the cortex and measuring expression of doublecortin (DCX), a microtubule-associated protein involved in neuronal migration, in humans and rhesus macaques. We found a striking decline in DCX expression (human and macaque) and density of white matter neurons (humans) during infancy, consistent with the arrival of new neurons in the early postnatal cortex. Considering the expansion of the brain during this time, the decline in white matter neuron density does not necessarily indicate reduced total numbers of white matter neurons in early postnatal life. Furthermore, numerous cells in the white matter and deep grey matter were positive for the migration-associated glycoprotein polysialiated-neuronal cell adhesion molecule and GAD65/67, suggesting that immature migrating neurons in the adult may be GABAergic. We also examined DCX mRNA in the PFC of adult schizophrenia patients (n?=?37) and matched controls (n?=?37) and did not find any difference in DCX mRNA expression. However, we report a negative correlation between DCX mRNA expression and white matter neuron density in adult schizophrenia patients, in contrast to a positive correlation in human development where DCX mRNA and white matter neuron density are higher earlier in life. Accumulation of neurons in the white matter in schizophrenia would be congruent with a negative correlation between DCX mRNA and white matter neuron density and support the hypothesis of a migration deficit in schizophrenia.

Fung, Samantha J.; Joshi, Dipesh; Allen, Katherine M.; Sivagnanasundaram, Sinthuja; Rothmond, Debora A.; Saunders, Richard; Noble, Pamela L.; Webster, Maree J.; Shannon Weickert, Cynthia

2011-01-01

181

Diffusion tensor and magnetization transfer MRI measurements of periventricular white matter hyperintensities in old age.  

PubMed

Regions of diffuse periventricular white matter hyperintensities (PVWMH) are a common finding on T(2)-weighted MRI scans of older subjects, but their aetiology remains unclear. The aim of this study was to characterize differences in water diffusion and magnetization transfer MRI parameters between macroscopically normal-appearing white matter (NAWM) and PVWMH in a cohort of normal older subjects. Forty-two non-demented 83-year olds underwent structural, diffusion tensor and magnetization transfer MRI. Mean diffusivity (), fractional anisotropy (FA), axial (lambda(ax)) and radial (lambda(rad)) diffusivity, and magnetization transfer ratio (MTR) were measured in both NAWM and PVWMH in frontal and parieto-occipital white matter, and centrum semiovale. For all three regions, PVWMH had greater , lambda(ax) and lambda(rad) than NAWM, while FA and MTR were significantly reduced compared with normal tissue (p<0.01). For PVWMH, MTR was significantly correlated (Spearman's rho in the range -0.93 to 0.70; p<0.01) with , FA, lambda(ax) and lambda(rad) in all three regions. Conversely, for NAWM, the only significant correlation between MTR and a water diffusion parameter was for lambda(rad) in parieto-occipital white matter (rho=-0.40; p<0.05), with all other correlations close to the rho=0 level. These data indicate that in normal white matter, characterized by structurally coherent cell membranes, the degree of water molecule diffusion and myelination are held within relatively tight limits. However, within PVWMH, MTR correlates strongly with water diffusion parameters probably because of the pathologically associated neuronal loss, demyelination and gliosis. PMID:17624630

Bastin, Mark E; Clayden, Jonathan D; Pattie, Alison; Gerrish, Iona F; Wardlaw, Joanna M; Deary, Ian J

2007-07-12

182

White Matter Development in Early Puberty: A Longitudinal Volumetric and Diffusion Tensor Imaging Twin Study  

PubMed Central

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.

Brouwer, Rachel M.; Mandl, Rene C. W.; Schnack, Hugo G.; van Soelen, Inge L. C.; van Baal, G. Caroline; Peper, Jiska S.; Kahn, Rene S.; Boomsma, Dorret I.; Pol, H. E. Hulshoff

2012-01-01

183

Relating Imaging Indices of White Matter Integrity and Volume in Healthy Older Adults  

Microsoft Academic Search

Age-related alterations in white matter have the potential to profoundly affect cognitive functioning. In fact, magnetic resonance imaging (MRI) studies using fractional anisotropy (FA) to measure white matter integrity reveal a positive correlation between FA and behavioral performance in older adults. Confounding these results are imaging studies demonstrating age-related white matter atrophy in some areas displaying altered FA, suggesting changes

Christina E. Hugenschmidt; Ann M. Peiffer; Robert A. Kraft; Ramon Casanova; Andrew R. Deibler; Jonathan H. Burdette; Joseph A. Maldjian; Paul J. Laurienti

2008-01-01

184

Vanishing White Matter Disease: A Review with Focus on Its Genetics  

ERIC Educational Resources Information Center

|Leukoencephalopathy with vanishing white matter (VWM) is an autosomal recessive brain disorder, most often with a childhood onset. Magnetic resonance imaging and spectroscopy indicate that, with time, increasing amounts of cerebral white matter vanish and are replaced by fluid. Autopsy confirms white matter rarefaction and cystic degeneration.…

Pronk, Jan C.; van Kollenburg, Barbara; Scheper, Gert C.; van der Knaap, Marjo S.

2006-01-01

185

Local white matter geometry from diffusion tensor gradients.  

PubMed

We introduce a mathematical framework for computing geometrical properties of white matter fibers directly from diffusion tensor fields. The key idea is to isolate the portion of the gradient of the tensor field corresponding to local variation in tensor orientation, and to project it onto a coordinate frame of tensor eigenvectors. The resulting eigenframe-centered representation then makes it possible to define scalar indices (or measures) that describe the local white matter geometry directly from the diffusion tensor field and its gradient, without requiring prior tractography. We derive new scalar indices of (1) fiber dispersion and (2) fiber curving, and we demonstrate them on synthetic and in vivo data. Finally, we illustrate their applicability to a group study on schizophrenia. PMID:19896542

Savadjiev, Peter; Kindlmann, Gordon L; Bouix, Sylvain; Shenton, Martha E; Westin, Carl-Fredrik

2009-11-05

186

Local white matter geometry indices from diffusion tensor gradients.  

PubMed

We introduce a framework for computing geometrical properties of white matter fibres directly from diffusion tensor fields. The key idea is to isolate the portion of the gradient of the tensor field corresponding to local variation in tensor orientation, and to project it onto a coordinate frame of tensor eigenvectors. The resulting eigenframe-centered representation makes it possible to define scalar geometrical measures that describe the underlying white matter fibres, directly from the diffusion tensor field and its gradient, without requiring prior tractography. We define two new scalar measures of (1) fibre dispersion and (2) fibre curving, and we demonstrate them on synthetic and in-vivo datasets. Finally, we illustrate their applicability in a group study on schizophrenia. PMID:20426006

Savadjiev, Peter; Kindlmann, Gordon; Bouix, Sylvain; Shenton, Martha E; Westin, Carl-Fredrik

2009-01-01

187

Local White Matter Geometry from Diffusion Tensor Gradients  

PubMed Central

We introduce a mathematical framework for computing geometrical properties of white matter fibres directly from diffusion tensor fields. The key idea is to isolate the portion of the gradient of the tensor field corresponding to local variation in tensor orientation, and to project it onto a coordinate frame of tensor eigenvectors. The resulting eigenframe-centered representation then makes it possible to define scalar indices (or measures) that describe the local white matter geometry directly from the diffusion tensor field and its gradient, without requiring prior tractography. We derive new scalar indices of (1) fibre dispersion and (2) fibre curving, and we demonstrate them on synthetic and in vivo data. Finally, we illustrate their applicability to a group study on schizophrenia.

Savadjiev, Peter; Kindlmann, Gordon L.; Bouix, Sylvain; Shenton, Martha E.; Westin, Carl-Fredrik

2010-01-01

188

Local White Matter Geometry from Diffusion Tensor Gradients  

PubMed Central

We introduce a mathematical framework for computing geometrical properties of white matter fibres directly from diffusion tensor fields. The key idea is to isolate the portion of the gradient of the tensor field corresponding to local variation in tensor orientation, and to project it onto a coordinate frame of tensor eigenvectors. The resulting eigenframe-centered representation then makes it possible to define scalar indices (or measures) that describe the local white matter geometry directly from the diffusion tensor field and its gradient, without requiring prior tractography. We derive new scalar indices of (1) fibre dispersion and (2) fibre curving, and we demonstrate them on synthetic and in vivo data. Finally, we illustrate their applicability to a group study on schizophrenia.

Savadjiev, Peter; Kindlmann, Gordon L.; Bouix, Sylvain; Shenton, Martha E.; Westin, Carl-Fredrik

2009-01-01

189

Tract-based morphometry for white matter group analysis  

Microsoft Academic Search

We introduce an automatic method that we call tract-based morphometry, or TBM, for measurement and analysis of diffusion MRI data along white matter fiber tracts. Using subject-specific tractography bundle segmentations, we generate an arc length parameterization of the bundle with point correspondences across all fibers and all subjects, allowing tract-based measurement and analysis. In this paper we present a quantitative

Lauren J. O'Donnell; Carl-Fredrik Westin; Alexandra J. Golby

2009-01-01

190

Multiple white matter tract abnormalities underlie cognitive impairment in RRMS  

Microsoft Academic Search

Diffusion tensor imaging (DTI) is a sensitive tool for detecting microstructural tissue damage in vivo. In this study, we investigated DTI abnormalities in individuals with relapsing remitting multiple sclerosis (RRMS) and examined the relations between imaging-based measures of white matter injury and cognitive impairment. DTI-derived metrics using tract-based spatial statistics (TBSS) were compared between 37 individuals with RRMS and 20

Hui Jing Yu; Christopher Christodoulou; Vikram Bhise; Daniel Greenblatt; Yashma Patel; Dana Serafin; Mirjana Maletic-Savatic; Lauren B. Krupp; Mark Wagshul

191

Sonographic demonstration of contusional white matter clefts in an infant.  

PubMed

In abused children cerebral contusion can lead to neurologic sequelae or mental retardation. Cerebral injury has been found with and without external evidence of head injury. We report the sonographic findings in a case of battered-child syndrome. Cerebral sonography could demonstrate cerebral contusion at the time of admission. On repeated examination white matter clefts developed in both frontal lobes. The sonographic findings were confirmed by CCT. PMID:6738817

Hausdorf, G; Helmke, K

1984-05-01

192

White Matter Microsusceptibility Changes in Patients With Hepatic Encephalopathy  

PubMed Central

We report a new radiological finding in two patients with hepatic encephalopathy. A new susceptibility-weighted (SWI) magnetic resonance imaging sequence revealed multiple bilateral microsusceptibility changes in the corpus callosum and white matter, while the conventional T1 and T2 weighted images were unremarkable. We postulate that the etiology of the microsusceptibility changes may be related to hepatic coagulopathy and other factors, such as impaired cerebral blood flow and brain edema.

Achiriloaie, Adina F.; Kido, Daniel; Wycliffe, Dan; Jacobson, J. Paul

2011-01-01

193

Probabilistic Clustering and Quantitative Analysis of White Matter Fiber Tracts  

Microsoft Academic Search

A novel framework for joint clustering and point-by-point mapping of white matter fiber pathways is presented. Accurate clus- tering of the trajectories into fiber bundles requires point correspon- dence along the fiber pathways determined. This knowledge is also crucial for any tract-oriented quantitative analysis. We employ an expectation- maximization (EM) algorithm to cluster the trajectories in a Gamma mixture model

Mahnaz Maddah; William M. Wells III; Simon K. Warfield; Carl-fredrik Westin; W. Eric L. Grimson

2007-01-01

194

Longitudinal Characterization of White Matter Maturation During Adolescence  

PubMed Central

Background: Late adolescence is comprised of considerable developmental transitions, though brain maturational changes during this period are subtle and difficult to quantitatively evaluate from standard brain imaging acquisitions. To date, primarily cross-sectional studies have characterized typical developmental changes during adolescence, but these processes need further description within a longitudinal framework. Method: To assess the developmental trajectory of typical white matter development, we examined 22 healthy adolescents with serial diffusion tensor images (DTI) collected at a mean age of 17.8 years and 16-months later. Diffusion parameters fractional anisotropy, and mean, radial, and axial diffusivity were subjected to whole-brain voxelwise time point comparisons using tract-based spatial statistics. Results: At follow-up, adolescents showed significant change (? 153 contiguous voxels each at p<.01) in diffusion properties, including in bilateral superior longitudinal fasciculi, superior corona radiata, anterior thalamic radiations, and posterior limb of the internal capsule. Overall, correlations with cognitive performances suggested behavioral improvement corresponding with white matter changes. Conclusion: These longitudinal DTI findings support continued microstructural change in white matter during late adolescence, and suggest ongoing refinement of projection and association fibers into early adulthood.

Bava, Sunita; Thayer, Rachel; Jacobus, Joanna; Ward, Megan; Jernigan, Terry L.; Tapert, Susan F.

2010-01-01

195

Predicting white matter integrity from multiple common genetic variants.  

PubMed

Several common genetic variants have recently been discovered that appear to influence white matter microstructure, as measured by diffusion tensor imaging (DTI). Each genetic variant explains only a small proportion of the variance in brain microstructure, so we set out to explore their combined effect on the white matter integrity of the corpus callosum. We measured six common candidate single-nucleotide polymorphisms (SNPs) in the COMT, NTRK1, BDNF, ErbB4, CLU, and HFE genes, and investigated their individual and aggregate effects on white matter structure in 395 healthy adult twins and siblings (age: 20-30 years). All subjects were scanned with 4-tesla 94-direction high angular resolution diffusion imaging. When combined using mixed-effects linear regression, a joint model based on five of the candidate SNPs (COMT, NTRK1, ErbB4, CLU, and HFE) explained ? 6% of the variance in the average fractional anisotropy (FA) of the corpus callosum. This predictive model had detectable effects on FA at 82% of the corpus callosum voxels, including the genu, body, and splenium. Predicting the brain's fiber microstructure from genotypes may ultimately help in early risk assessment, and eventually, in personalized treatment for neuropsychiatric disorders in which brain integrity and connectivity are affected. PMID:22510721

Kohannim, Omid; Jahanshad, Neda; Braskie, Meredith N; Stein, Jason L; Chiang, Ming-Chang; Reese, April H; Hibar, Derrek P; Toga, Arthur W; McMahon, Katie L; de Zubicaray, Greig I; Medland, Sarah E; Montgomery, Grant W; Martin, Nicholas G; Wright, Margaret J; Thompson, Paul M

2012-04-18

196

Predicting White Matter Integrity from Multiple Common Genetic Variants  

PubMed Central

Several common genetic variants have recently been discovered that appear to influence white matter microstructure, as measured by diffusion tensor imaging (DTI). Each genetic variant explains only a small proportion of the variance in brain microstructure, so we set out to explore their combined effect on the white matter integrity of the corpus callosum. We measured six common candidate single-nucleotide polymorphisms (SNPs) in the COMT, NTRK1, BDNF, ErbB4, CLU, and HFE genes, and investigated their individual and aggregate effects on white matter structure in 395 healthy adult twins and siblings (age: 20–30 years). All subjects were scanned with 4-tesla 94-direction high angular resolution diffusion imaging. When combined using mixed-effects linear regression, a joint model based on five of the candidate SNPs (COMT, NTRK1, ErbB4, CLU, and HFE) explained ?6% of the variance in the average fractional anisotropy (FA) of the corpus callosum. This predictive model had detectable effects on FA at 82% of the corpus callosum voxels, including the genu, body, and splenium. Predicting the brain's fiber microstructure from genotypes may ultimately help in early risk assessment, and eventually, in personalized treatment for neuropsychiatric disorders in which brain integrity and connectivity are affected.

Kohannim, Omid; Jahanshad, Neda; Braskie, Meredith N; Stein, Jason L; Chiang, Ming-Chang; Reese, April H; Hibar, Derrek P; Toga, Arthur W; McMahon, Katie L; de Zubicaray, Greig I; Medland, Sarah E; Montgomery, Grant W; Martin, Nicholas G; Wright, Margaret J; Thompson, Paul M

2012-01-01

197

White Matter and Cognition in Adults Who Were Born Preterm  

PubMed Central

Background and Purpose Individuals born very preterm (before 33 weeks of gestation, VPT) are at risk of damage to developing white matter, which may affect later cognition and behaviour. Methods We used diffusion tensor MRI (DT-MRI) to assess white matter microstructure (fractional anisotropy; FA) in 80 VPT and 41 term-born individuals (mean age 19.1 years, range 17–22, and 18.5 years, range17–22 years, respectively). VPT individuals were part of a 1982–1984 birth cohort which had been followed up since birth; term individuals were recruited by local press advertisement. General intellectual function, executive function and memory were assessed. Results The VPT group had reduced FA in four clusters, and increased FA in four clusters relative to the Term group, involving several association tracts of both hemispheres. Clusters of increased FA were associated with more severe neonatal brain injury in the VPT group. Clusters of reduced FA were associated with lower birth weight and perinatal hypoxia, and with reduced adult cognitive performance in the VPT group only. Conclusions Alterations of white matter microstructure persist into adulthood in VPT individuals and are associated with cognitive function.

Allin, Matthew P. G.; Kontis, Dimitris; Walshe, Muriel; Wyatt, John; Barker, Gareth J.; Kanaan, Richard A. A.; McGuire, Philip; Rifkin, Larry; Murray, Robin M.; Nosarti, Chiara

2011-01-01

198

Regional Social Capital: Why it Matters  

Microsoft Academic Search

Malecki E. J. Regional social capital: why it matters, Regional Studies. Social capital refers to a culture of interaction among people, with productive economic outcomes. Social capital promotes regional learning both within a region and beyond, as it reinforces openness to the ideas of others. Regional cultures vary in the degree to which people – individually and within their organizations

Edward J. Malecki

2011-01-01

199

Regional Social Capital: Why it Matters  

Microsoft Academic Search

Malecki E. J. Regional social capital: why it matters, Regional Studies. Social capital refers to a culture of interaction among people, with productive economic outcomes. Social capital promotes regional learning both within a region and beyond, as it reinforces openness to the ideas of others. Regional cultures vary in the degree to which people – individually and within their organizations

Edward J. Malecki

2012-01-01

200

Atrophy and dysfunction of parahippocampal white matter in mild Alzheimer's disease‡  

PubMed Central

In addition to atrophy of mesial temporal lobe structures critical for memory function, white matter projections to the hippocampus may be compromised in individuals with mild Alzheimer’s disease (AD), thereby compounding the memory difficulty. In the present study, we used high-resolution structural imaging and diffusion tensor imaging techniques to examine micro-structural alterations in the parahippocampal white matter (PWM) region that includes the perforant path. Results demonstrated white matter volume loss bilaterally in the PWM in patients with mild AD. In addition, the remaining white matter had significantly lower fractional anisotropy and higher mean diffusivity values. Both increased mean diffusivity and volume reduction in the PWM were associated with memory performance and ApoE ?4 allele status. These findings indicate that, in addition to partial disconnection of the hippocampus from incoming sensory information due to volume loss in PWM, micro-structural alterations in remaining fibers may further degrade impulse transmission to the hippocampus and accentuate memory dysfunction. The results reported here also suggest that ApoE ?4 may exacerbate PWM changes.

Wang, Changsheng; Stebbins, Glenn T.; Medina, David A.; Shah, Raj C.; Bammer, Roland; Moseley, Michael E.; de Toledo-Morrell, Leyla

2010-01-01

201

White Matter Integrity, Creativity, and Psychopathology: Disentangling Constructs with Diffusion Tensor Imaging  

PubMed Central

That creativity and psychopathology are somehow linked remains a popular but controversial idea in neuroscience research. Brain regions implicated in both psychosis-proneness and creative cognition include frontal projection zones and association fibers. In normal subjects, we have previously demonstrated that a composite measure of divergent thinking (DT) ability exhibited significant inverse relationships in frontal lobe areas with both cortical thickness and metabolite concentration of N-acetyl-aspartate (NAA). These findings support the idea that creativity may reside upon a continuum with psychopathology. Here we examine whether white matter integrity, assessed by Fractional Anisotropy (FA), is related to two measures of creativity (Divergent Thinking and Openness to Experience). Based on previous findings, we hypothesize inverse correlations within fronto-striatal circuits. Seventy-two healthy, young adult (18–29 years) subjects were scanned on a 3 Tesla scanner with Diffusion Tensor Imaging. DT measures were scored by four raters (??=?.81) using the Consensual Assessment Technique, from which a composite creativity index (CCI) was derived. We found that the CCI was significantly inversely related to FA within the left inferior frontal white matter (t?=?5.36, p?=?.01), and Openness was inversely related to FA within the right inferior frontal white matter (t?=?4.61, p?=?.04). These findings demonstrate an apparent overlap in specific white matter architecture underlying the normal variance of divergent thinking, openness, and psychotic-spectrum traits, consistent with the idea of a continuum.

Jung, Rex E.; Grazioplene, Rachael; Caprihan, Arvind; Chavez, Robert S.; Haier, Richard J.

2010-01-01

202

Microstructural abnormalities of white matter differentiate pediatric and adult onset bipolar disorder  

PubMed Central

Background White matter microstructure, known to undergo significant developmental transformation, is abnormal in bipolar disorder (BD). Available evidence suggests that white matter deviation may be more pronounced in pediatric than adult onset BD. This study aimed to examine how white matter microstructure deviates from a typical maturational trajectory in BD. Methods Fractional anisotropy (FA) was measured in 35 individuals presenting with first episode BD (type I) and 46 healthy controls (HC) (aged 9–42) using diffusion tensor imaging (DTI). Patients were medication free and close to illness onset at the time of DTI scans. Tract based spatial statistics were used to examine the center of white matter tracts, and FA was extracted from nine tracts of interest. Axial, radial, and mean diffusivity were examined in post-hoc analyses. Results The left anterior limb of the internal capsule (ALIC) showed significantly lower FA in pediatric than adult onset BD. The lower FA in BD was due primarily to greater radial rather than a decrease in axial diffusivity. Conclusions ALIC connects the frontal lobes with archistriatum, thalamus, and medial temporal regions, and alteration in these pathways may contribute to mood dysregulation in BD. Abnormalities in this pathway appear to be associated with an earlier onset of illness and thus may reflect a greater liability for illness.

Lu, Lisa H; Zhou, Xiaohong Joe; Fitzgerald, Jacklynn; Keedy, Sarah K; Reilly, James L; Passarotti, Alessandra M; Sweeney, John A; Pavuluri, Mani

2012-01-01

203

Why So Impulsive? White Matter Alterations Are Associated With Impulsivity in Chronic Marijuana Smokers  

PubMed Central

Difficulty monitoring and inhibiting impulsive behaviors has been reported in marijuana (MJ) smokers; neuroimaging studies, which examined frontal systems in chronic MJ smokers, have reported alterations during inhibitory tasks. Diffusion tensor imaging (DTI) provides a quantitative estimate of white matter integrity at the microstructural level. We applied DTI, clinical ratings, and impulsivity measures to explore the hypotheses that chronic, heavy MJ smokers would demonstrate alterations in white matter microstructure and a different association between white matter measures and impulsivity relative to nonsmoking control subjects (NS). Fractional anisotropy (FA), a measure of directional coherence, and trace, a measure of overall diffusivity, were calculated for 6 locations including bilateral frontal regions in 15 chronic MJ smokers and 15 NS. Subjects completed clinical rating scales, including the Barratt Impulsivity Scale (BIS). Analyses revealed significant reductions in left frontal FA in MJ smokers relative to NS and significantly higher levels of trace in the right genu. MJ smokers also had significantly higher BIS total and motor subscale scores relative to NS, which were positively correlated with left frontal FA values. Finally, age of onset of MJ use was positively correlated with frontal FA values and inversely related to trace. These data represent the first report of significant alterations in frontal white matter tracts associated with measures of impulsivity in chronic MJ smokers. Early MJ use may result in reduced FA and increased diffusivity, which may be associated with increased impulsivity, and ultimately contribute to the initiation of MJ use or the inability to discontinue use.

Gruber, Staci A.; Silveri, Marisa M.; Dahlgren, Mary Kathryn; Yurgelun-Todd, Deborah

2012-01-01

204

Alterations of White Matter Integrity Related to the Season of Birth in Schizophrenia: A DTI Study  

PubMed Central

In schizophrenia there is a consistent epidemiological finding of a birth excess in winter and spring. Season of birth is thought to act as a proxy indicator for harmful environmental factors during foetal maturation. There is evidence that prenatal exposure to harmful environmental factors may trigger pathologic processes in the neurodevelopment, which subsequently increase the risk of schizophrenia. Since brain white matter alterations have repeatedly been found in schizophrenia, the objective of this study was to investigate whether white matter integrity was related to the season of birth in patients with schizophrenia. Thirty-four patients with schizophrenia and 33 healthy controls underwent diffusion tensor imaging. Differences in the fractional anisotropy maps of schizophrenia patients and healthy controls born in different seasons were analysed with tract-based spatial statistics. A significant main effect of season of birth and an interaction of group and season of birth showed that patients born in summer had significantly lower fractional anisotropy in widespread white matter regions than those born in the remainder of the year. Additionally, later age of schizophrenia onset was found in patients born in winter months. The current findings indicate a relationship of season of birth and white matter alterations in schizophrenia and consequently support the neurodevelopmental hypothesis of early pathological mechanisms in schizophrenia.

Giezendanner, Stephanie; Walther, Sebastian; Razavi, Nadja; Van Swam, Claudia; Fisler, Melanie Sarah; Soravia, Leila Maria; Andreotti, Jennifer; Schwab, Simon; Jann, Kay; Wiest, Roland; Horn, Helge; Muller, Thomas Jorg; Dierks, Thomas; Federspiel, Andrea

2013-01-01

205

Segmentation of MRI brain scans into gray matter, white matter, and CSF  

Microsoft Academic Search

An algorithm is described that can separate gray matter, white matter and CSF in brain scans taken with 3DFFT T1- weighted gradient echo magnetic resonance imaging. Although the algorithm is fully automated, it requires brain contours as input that utilize user-defined features. The inter- and intra-operator errors stemming from the variability of the contour definition and affecting the segmentation were

Tamas Sandor; Hoo-Tee Ong; Vladimir Valtchinov; Marilyn Albert; Ferenc A. Jolesz

1997-01-01

206

Testing the white matter retrogenesis hypothesis of cognitive aging.  

PubMed

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. 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 2 prototypical early-myelinated fiber tracts (posterior limb of the internal capsule, cerebral peduncles) and 2 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 7-30 years) and degenerative trajectory (ages 31-87 years), and tested whether the measures of white matter coherence mediated age-related cognitive decline in the older group. 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. 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

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

2011-07-23

207

Reduced microstructural integrity of the white matter underlying anterior cingulate cortex is associated with increased saccadic latency in schizophrenia.  

PubMed

The anterior cingulate cortex (ACC) is a key component of a network that directs both spatial attention and saccadic eye movements, which are tightly linked. Diffusion tensor imaging (DTI) has demonstrated reduced microstructural integrity of the anterior cingulum bundle as indexed by fractional anisotropy (FA) in schizophrenia, but the functional significance of these abnormalities is unclear. Using DTI, we examined the white matter underlying anterior cingulate cortex in schizophrenia to determine whether reduced FA is associated with prolonged latencies of volitional saccades. Seventeen chronic, medicated schizophrenia outpatients and nineteen healthy controls had high-resolution DTI scans. FA maps were registered to structural scans and mapped across participants using a surface-based coordinate system. Cingulate white matter was divided into rostral and dorsal anterior regions and a posterior region. Patients showed reduced FA in cingulate white matter of the right hemisphere. Reduced FA in the white matter underlying anterior cingulate cortex, frontal eye field, and posterior parietal cortex of the right hemisphere was associated with longer saccadic latencies in schizophrenia, though given the relatively small sample size, these relations warrant replication. These findings demonstrate that in schizophrenia, increased latency of volitional saccades is associated with reduced microstructural integrity of the white matter underlying key cortical components of a right-hemisphere dominant network for visuospatial attention and ocular motor control. Moreover, they suggest that anterior cingulate white matter abnormalities contribute to slower performance of volitional saccades and to inter-individual variability of saccadic latency in chronic, medicated schizophrenia. PMID:17590354

Manoach, Dara S; Ketwaroo, G Avinash; Polli, Frida E; Thakkar, Katharine N; Barton, Jason J S; Goff, Donald C; Fischl, Bruce; Vangel, Mark; Tuch, David S

2007-05-21

208

Segmentation of MRI brain scans into gray matter, white matter, and CSF  

NASA Astrophysics Data System (ADS)

An algorithm is described that can separate gray matter, white matter and CSF in brain scans taken with 3DFFT T1- weighted gradient echo magnetic resonance imaging. Although the algorithm is fully automated, it requires brain contours as input that utilize user-defined features. The inter- and intra-operator errors stemming from the variability of the contour definition and affecting the segmentation were assessed by using coronal brain scans of 19 subjects. The inter-operator errors were (1.61 plus or minus 2.38)% (P equals 0.01) for gray matter, (0.31 plus or minus 2.06)% (P equals 0.53) for white matter and (0.28 plus or minus 3.84)% (P equals 0.76) for cerebrospinal fluid (CSF). the intra- operator error was (0.28 plus or minus 0.55)% (P greater than 0.04) for gray matter, (0.40 plus or minus 0.37)% (P equals 0.0002) for white matter and (0.26 plus or minus 1.31)% (P equals 0.39) for CSF.

Sandor, Tamas; Ong, Hoo-Tee; Valtchinov, Vladimir; Albert, Marilyn; Jolesz, Ferenc A.

1997-04-01

209

Brain metabolite abnormalities in the white matter of elderly schizophrenic subjects: implication for glial dysfunction  

PubMed Central

Background Abnormalities in the white matter of the brain may occur in individuals with schizophrenia as well as with normal aging. Therefore, elderly schizophrenic patients may suffer further cognitive decline as they age. This study determined whether elderly schizophrenia participants, especially those with declined cognitive function (CDR>1), show white matter metabolite abnormalities on proton magnetic resonance spectroscopy (1H MRS), and whether there are group differences in age-dependent changes in these brain metabolites. Method 23 elderly schizophrenic and 22 comparison participants fulfilling study criteria were enrolled. Localized, short echo-time 1H MRS at 4 Tesla was used to assess neurometabolite concentrations in several white matter regions. Results Compared to healthy subjects, schizophrenic participants had lower N-acetyl compounds (NA, ?12.6%, p=0.0008), lower myoinositol (MI, ?16.4%, p=0.026) and higher glutamate+glutamine (GLX, +28.7%, p=0.0016) concentrations across brain regions. Schizophrenic participants with CDR?1 showed the lowest NA in the frontal and temporal regions compared to controls. Interactions between age and schizophrenia status on total creatine (CR) and choline-containing compounds (CHO) were observed; only schizophrenic participants showed age-related decreases of these two metabolites in the right frontal region. Conclusion Decreased NA in these white matter brain regions likely reflects reduced neuronal content associated with decreased synapses and neuronal cell volumes. The elevated GLX, if reflecting elevated glutamate, could result from excess neuronal glutamate release or glial dysfunction in glutamate re-uptake. The decreased MI in participants with schizophrenia suggests decreased glial content or dysfunctional glia, which might result from glutamate-mediated toxicity.

Chang, Linda; Friedman, Joseph; Ernst, Thomas; Zhong, Kai; Tsopelas, Nicholas D.; Davis, Kenneth

2008-01-01

210

Alterations in White Matter Evident Before the Onset of Psychosis  

PubMed Central

Background Psychotic disorders are associated with widespread reductions in white matter (WM) integrity. However, the stage at which these abnormalities first appear and whether they are correlates of psychotic illness, as opposed to an increased vulnerability to psychosis, is unclear. We addressed these issues by using diffusion tensor imaging (DTI) to study subjects at ultra high risk (UHR) of psychosis before and after the onset of illness. Methods Thirty-two individuals at UHR for psychosis, 32 controls, and 15 patients with first-episode schizophrenia were studied using DTI. The UHR subjects and controls were re-scanned after 28 months. During this period, 8 UHR subjects had developed schizophrenia. Between-group differences in fractional anisotropy (FA) and diffusivity were evaluated cross sectionally and longitudinally using a nonparametric voxel-based analysis. Results At baseline, WM DTI properties were significantly different between the 3 groups (P < .001). Relative to controls, first-episode patients showed widespread reductions in FA and increases in diffusivity. DTI indices in the UHR group were intermediate relative to those in the other 2 groups. Longitudinal analysis revealed a significant group by time interaction in the left frontal WM (P < .001). In this region, there was a progressive reduction in FA in UHR subjects who developed psychosis that was not evident in UHR subjects who did not make a transition. Conclusions People at UHR for psychosis show alterations in WM qualitatively similar to, but less severe than, those in patients with schizophrenia. The onset of schizophrenia may be associated with a progressive reduction in the integrity of the frontal WM.

Carletti, Francesco; Woolley, James B.; Bhattacharyya, Sagnik; Perez-Iglesias, Rocio; Fusar Poli, Paolo; Valmaggia, Lucia; Broome, Matthew R.; Bramon, Elvira; Johns, Louise; Giampietro, Vincent; Williams, Steve C. R.; Barker, Gareth J.; McGuire, Philip K.

2012-01-01

211

Functional Diffusion Tensor Imaging: Measuring Task-Related Fractional Anisotropy Changes in the Human Brain along White Matter Tracts  

Microsoft Academic Search

BackgroundFunctional neural networks in the human brain can be studied from correlations between activated gray matter regions measured with fMRI. However, while providing important information on gray matter activation, no information is gathered on the co-activity along white matter tracts in neural networks.Methodology\\/Principal FindingsWe report on a functional diffusion tensor imaging (fDTI) method that measures task-related changes in fractional anisotropy

René C. W. Mandl; Hugo G. Schnack; Marcel P. Zwiers; Arjen van der Schaaf; René S. Kahn; Hilleke E. Hulshoff Pol; Eric Warrant

2008-01-01

212

Diffusion Tensor Magnetic Resonance Imaging Finding of Discrepant Fractional Anisotropy Between the Frontal and Parietal Lobes After Whole-Brain Irradiation in Childhood Medulloblastoma Survivors: Reflection of Regional White Matter Radiosensitivity?  

SciTech Connect

Purpose: To test the hypothesis that fractional anisotropy (FA) is more severely reduced in white matter of the frontal lobe compared with the parietal lobe after receiving the same whole-brain irradiation dose in a cohort of childhood medulloblastoma survivors. Methods and Materials: Twenty-two medulloblastoma survivors (15 male, mean [{+-} SD] age = 12.1 {+-} 4.6 years) and the same number of control subjects (15 male, aged 12.0 {+-} 4.2 years) were recruited for diffusion tensor magnetic resonance imaging scans. Using an automated tissue classification method and the Talairach Daemon atlas, FA values of frontal and parietal lobes receiving the same radiation dose, and the ratio between them were quantified and denoted as FFA, PFA, and FA{sub f/p}, respectively. The Mann-Whitney U test was used to test for significant differences of FFA, PFA, and FA{sub f/p} between medulloblastoma survivors and control subjects. Results: Frontal lobe and parietal lobe white matter FA were found to be significantly less in medulloblastoma survivors compared with control subjects (frontal p = 0.001, parietal p = 0.026). Moreover, these differences were found to be discrepant, with the frontal lobe having a significantly larger difference in FA compared with the parietal lobe. The FA{sub f/p} of control and medulloblastoma survivors was 1.110 and 1.082, respectively (p = 0.029). Conclusion: Discrepant FA changes after the same irradiation dose suggest radiosensitivity of the frontal lobe white matter compared with the parietal lobe. Special efforts to address the potentially vulnerable frontal lobe after treatment with whole-brain radiation may be needed so as to balance disease control and treatment-related morbidity.

Qiu Deqiang [Department of Diagnostic Radiology, Queen Mary Hospital, University of Hong Kong, Hong Kong (China); Kwong, Dora [Department of Clinical Oncology, Queen Mary Hospital, University of Hong Kong, Hong Kong (China); Chan, Godfrey [Department of Pediatric and Adolescent Medicine, Queen Mary Hospital, University of Hong Kong, Hong Kong (China); Leung, Lucullus [Department of Oncology, Princess Margaret Hospital, Hong Kong (China); Khong, P.-L. [Department of Diagnostic Radiology, Queen Mary Hospital, University of Hong Kong, Hong Kong (China)], E-mail: plkhong@hkucc.hku.hk

2007-11-01

213

Mapping magnetic susceptibility anisotropies of white matter in vivo in the human brain at 7 T.  

PubMed

High-resolution magnetic resonance phase- or frequency-shift images acquired at high field show contrast related to magnetic susceptibility differences between tissues. Such contrast varies with the orientation of the organ in the field, but the development of quantitative susceptibility mapping (QSM) has made it possible to reproducibly image the intrinsic tissue susceptibility contrast. However, recent studies indicate that magnetic susceptibility is anisotropic in brain white matter and, as such, needs to be described by a symmetric second-rank tensor( ??). To fully determine the elements of this tensor, it would be necessary to acquire frequency data at six or more orientations. Assuming cylindrical symmetry of the susceptibility tensor in myelinated white matter fibers, we propose a simplified method to reconstruct the susceptibility tensor in terms of a mean magnetic susceptibility, MMS=(?(//)+2 ?(?))/3 and a magnetic susceptibility anisotropy, MSA=?(//)-?(?), where ?(//) and ?(?) are susceptibility parallel and perpendicular to the white matter fiber direction, respectively. Computer simulations show that with a practical head rotation angle of around 20°-30°, four head orientations suffice to reproducibly reconstruct the tensor with good accuracy. We tested this approach on whole brain 1 × 1 × 1 mm(3) frequency data acquired from five healthy subjects at 7 T. The frequency information from phase images collected at four head orientations was combined with the fiber direction information extracted from diffusion tensor imaging (DTI) to map the white matter susceptibility tensor. The MMS and MSA were quantified for regions in several large white matter fiber structures, including the corona radiata, posterior thalamic radiation and corpus callosum. MMS ranged from -0.037 to -0.053 ppm (referenced to CSF being about zero). MSA values could be quantified without the need for a reference and ranged between 0.004 and 0.029 ppm, in line with the expectation that the susceptibility perpendicular to the fiber is more diamagnetic than the one parallel to it. PMID:22561358

Li, Xu; Vikram, Deepti S; Lim, Issel Anne L; Jones, Craig K; Farrell, Jonathan A D; van Zijl, Peter C M

2012-04-28

214

White Matter Integrity Pre- and Post Marijuana and Alcohol Initiation in Adolescence  

PubMed Central

Characterizing the effects of alcohol and marijuana use on adolescent brain development is important for understanding potential alterations in neurodevelopment. Several cross sectional studies have identified group differences in white matter integrity after initiation of heavy alcohol and marijuana use, however none have explored white matter trajectories in adolescents pre- and post initiation of use, particularly for marijuana users. This study followed 16 adolescents with minimal alcohol and marijuana use at ages 16–18 over three years. At follow-up, teens were 19–22 years old; half of the participants initiated heavy alcohol use and half initiated heavy alcohol and marijuana use. Repeated-measures ANOVA revealed 20 clusters in association and projection fibers tracts (p < 0.01) in which a group by time interaction was found. Most consistently, white matter integrity (i.e., fractional anisotropy) decreased for those who initiated both heavy alcohol and marijuana use over the follow-up interval. No effect of time or change in white matter integrity was seen for those who initiated alcohol use only in the majority of clusters. In most regions, at the baseline time point, teens who would later initiate both alcohol and marijuana use demonstrated white matter integrity greater than or equal to teens that initiated alcohol use only. Findings suggest poorer tissue integrity associated with combined initiation of heavy alcohol and marijuana use in late adolescence. While OPEN ACCESS pre-existing differences may also be related to likelihood of substance use, the present data suggest an effect on tissue integrity for these teens transitioning to combined alcohol and marijuana use in later adolescence.

Jacobus, Joanna; Squeglia, Lindsay M.; Infante, M. Alejandra; Bava, Sunita; Tapert, Susan F.

2013-01-01

215

Distinctive disruption patterns of white matter tracts in Alzheimer's disease with full diffusion tensor characterization  

PubMed Central

To characterize the white matter structural changes at the tract level and tract group level, comprehensive analysis with four metrics derived from DTI, fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AxD) and radial diffusivity (RD), was conducted. Tract groups, namely limbic, commissural, association and projection tracts, include white matter tracts of similar functions. DTI data were acquired from 61 subjects (26 AD, 11 subjects with amnestic mild cognitive impairment or aMCI, 24 age-matched controls). An atlas-based approach was used to survey 30 major cerebral white matter tracts with the measurements of FA, MD, AxD and RD. Regional cortical atrophy and cognitive functions of AD patients were also measured to correlate with the structural changes of white matter. Synchronized structural changes of cingulum bundle and fornix, both of which are part of limbic tract group, were revealed. Widespread yet distinctive structural changes were found in limbic, commissural, association and projection tract groups between control and AD subjects. Specifically, FA, MD and RD of limbic tracts, FA, MD, AxD and RD of commissural tracts, MD, AxD and RD of association tracts and MD and AxD of projection tracts are significantly different between AD patients and control subjects. In contrast, the comparison between aMCI and control subjects shows disruption only in the limbic and commissural tract groups of aMCI subjects. MD values of all tract groups of AD patients are significantly correlated to cognitive functions. Difference between AD and control and that between MCI and control indicates a progression pattern of white matter disruption from limbic and commissural tract group to other tract groups. High correlation between FA, MD and RD measurements from limbic tracts and cortical atrophy suggests the disruption of the limbic tract group is caused by the neuronal damage.

Huang, Hao; Fan, Xin; Weiner, Myron; Martin-Cook, Kristin; Xiao, Guanghua; Davis, Jeannie; Devous, Michael; Rosenberg, Roger; Diaz-Arrastia, Ramon

2011-01-01

216

MS vs. HD: can white matter and subcortical gray matter pathology be distinguished neuropsychologically?  

PubMed

This study was conducted to examine the neuropsychological effects of white matter and subcortical gray matter pathology. Nineteen patients with multiple sclerosis (MS), 16 with Huntington's disease (HD), and 17 normal controls (NC) participated. Participants completed the California Verbal Learning Test (CVLT), Rotary Pursuit (RP) and Mirror Tracing (MT) tasks, and the Symbol Digit Modalities Test (SDMT). The principal findings pertain to a dissociation in procedural memory: on RP, the HD group demonstrated impaired sequence learning compared to the MS group, which performed similarly to the NC group, yet on MT, the MS and HD groups demonstrated normal perceptual-motor integration learning. On the CVLT, both patient groups performed better on recognition than on recall. On the SDMT, both patient groups performed worse than the NC group, with the HD group performing more poorly than the MS and NC groups. These results suggest that involvement of white and subcortical gray matter may produce different neuropsychological effects. PMID:17365249

Lafosse, Jose M; Corboy, John R; Leehey, Maureen A; Seeberger, Lauren C; Filley, Christopher M

2007-02-01

217

Age-related changes in parahippocampal white matter integrity: a diffusion tensor imaging study.  

PubMed

The axons in the parahippocampal white matter (PWM) region that includes the perforant pathway relay multimodal sensory information, important for memory function, from the entorhinal cortex to the hippocampus. Previous work suggests that the integrity of the PWM shows changes in individuals with amnestic mild cognitive impairment and is further compromised as Alzheimer's disease progresses. The present study was undertaken to determine the effects of healthy aging on macro- and micro-structural alterations in the PWM. The study characterized in vivo white matter changes in the parahippocampal region that includes the perforant pathway in cognitively healthy young (YNG, n=21) compared to cognitively healthy older (OLD, n=21) individuals using volumetry, diffusion tensor imaging (DTI) and tractography. Results demonstrated a significant reduction in PWM volume in old participants, with further indications of reduced integrity of remaining white matter fibers. In logistic regressions, PWM volume, memory performance and DTI indices of PWM integrity were significant indicator variables for differentiating the young and old participants. Taken together, these findings suggest that age-related alterations do occur in the PWM region and may contribute to the normal decline in memory function seen in healthy aging by degrading information flow to the hippocampus. PMID:22561887

Rogalski, E; Stebbins, G T; Barnes, C A; Murphy, C M; Stoub, T R; George, S; Ferrari, C; Shah, R C; deToledo-Morrell, L

2012-04-25

218

Quantitative fiber tracking of lateral and interhemispheric white matter systems in normal aging: Relations to timed performance  

Microsoft Academic Search

The integrity of white matter, as measured in vivo with diffusion tensor imaging (DTI), is disrupted in normal aging. A current consensus is that in adults advancing age affects anterior brain regions disproportionately more than posterior regions; however, the mainstay of studies supporting this anterior–posterior gradient is based primarily on measures of the corpus callosum. Using our quantitative fiber tracking

Edith V. Sullivan; Torsten Rohlfing; Adolf Pfefferbaum

2010-01-01

219

Cerebral White Matter Integrity Mediates Adult Age Differences in Cognitive Performance  

ERIC Educational Resources Information Center

|Previous research has established that age-related decline occurs in measures of cerebral white matter integrity, but the role of this decline in age-related cognitive changes is not clear. To conclude that white matter integrity has a mediating (causal) contribution, it is necessary to demonstrate that statistical control of the white

Madden, David J.; Spaniol, Julia; Costello, Matthew C.; Bucur, Barbara; White, Leonard E.; Cabeza, Roberto; Davis, Simon W.; Dennis, Nancy A.; Provenzale, James M.; Huettel, Scott A.

2009-01-01

220

White and Gray Matter Abnormalities in Narcolepsy with Cataplexy  

PubMed Central

Study Objectives: The authors applied diffusion-tensor imaging including measurements of mean diffusivity (MD), which is a parameter of brain tissue integrity, fractional anisotropy (FA), which is a parameter of neuronal fiber integrity, and voxel-based morphometry, which is a measure of gray and white matter volume, to detect brain tissue changes in patients with narcolepsy-cataplexy. Design: N/A. Patients: Patients with narcolepsy-cataplexy (n = 16) and age-matched healthy control subjects (n = 12) were studied. Interventions: Whole cerebral MD, FA measures, and the volumes of the gray and white matter compartments were analyzed using statistical parametric mapping. Measurement and Results: Significant MD increases and concomitant FA decreases were localized in the fronto-orbital cortex (P < 0.001) and the anterior cingulate (FA, P < 0.001; MD, P = 0.03) in narcolepsy-cataplexy. Additional MD increases without FA changes were detected in the ventral tegmental area, the dorsal raphe nuclei (P < 0.001), and the hypothalamus (P < 0.01). FA signal decreases were observed in the white matter tracts of the inferior frontal and inferior temporal cortices of narcolepsy-cataplexy patients (P < 0.001). Brain volume loss was evident in focal areas of the inferior and superior temporal cortices (P < 0.001) and the cingulate (P = 0.038). Conclusions: Areas of increased diffusivity in the hypothalamus appear consistent with hypocretinergic cell loss reported in narcolepsy-cataplexy. Signal abnormalities in the ventral tegmental area and the dorsal raphe nuclei correspond to major synaptic targets of hypocretin neurons that were associated with the regulation of the sleep-wake cycle. Brain tissue alterations identified in the frontal cortex and cingulate are crucial in the maintenance of attention and reward-dependent decision making, both known to be impaired in narcolepsy-cataplexy. Citation: Scherfler C; Frauscher B; Schocke M; Nocker M; Gschliesser V; Ehrmann L; Niederreiter M; Esterhammer R; Seppi K; Brandauer E; Poewe W; Högl B. White and gray matter abnormalities in narcolepsy with cataplexy. SLEEP 2012;35(3):345-351.

Scherfler, Christoph; Frauscher, Birgit; Schocke, Michael; Nocker, Michael; Gschliesser, Viola; Ehrmann, Laura; Niederreiter, Markus; Esterhammer, Regina; Seppi, Klaus; Brandauer, Elisabeth; Poewe, Werner; Hogl, Birgit

2012-01-01

221

Antidepressant Treatment Normalizes White Matter Volume in Patients with Major Depression  

PubMed Central

Objective To investigate white matter volume abnormalities in patients with major depression and the effects of antidepressant treatment on white matter volume. Method Magnetic resonance imaging (MRI) was performed on 32 treatment-naïve depressed patients, 17 recovered patients who had received antidepressant treatment and subsequently achieved clinical recovery and 34 matched controls. Results Relative to the healthy controls, the treatment-naïve depressed patients showed increased white matter volumes in the left dorsolateral prefrontal cortex (DLPFC) and left putamen and reduced white matter volumes in the left cerebellum posterior lobe and left inferior parietal lobule. For the treatment-naïve patients, the length in months of the current depressive episode was positively correlated with the white matter volumes in both the left DLPFC and left putamen. In the recovered patients, the differences in white matter volume were no longer statistically significant relative to healthy controls. No significant difference was found in the total white matter volume among the three groups. Conclusions This study demonstrates that there were alterations in the white matter volumes of depressed patients, which might disrupt the neural circuits that are involved in emotional and cognitive function and thus contribute to the pathophysiology of depression. The finding of the significant correlations between refractoriness and the white matter volumes in the left DLPFC and left putamen combined with the finding that antidepressant treatment normalized the white matter volume of recovered patients, suggests that a quantitative, structural MRI measurement could act as a potential biomarker in depression therapy for individual subjects.

Liu, Yadong; Shen, Hui; Li, Yaming; Hu, Dewen

2012-01-01

222

The Application of DTI to Investigate White Matter Abnormalities in Schizophrenia  

PubMed Central

Schizophrenia is a serious and disabling mental disorder that affects approximately 1% of the general population, with often devastating effects on the psychological and financial resources of the patient, family, and larger community. The etiology of schizophrenia is not known, although it likely involves several interacting biological and environmental factors that predispose an individual to schizophrenia. However, although the underlying pathology remains unknown, it has been believed that brain abnormalities would ultimately be linked to the etiology of schizophrenia. This theory was rekindled in the 1970s, when the first computer-assisted tomography (CT) study showed enlarged lateral ventricles in schizophrenia. Since that time, there have been many improvements in MR acquisition and image processing, including the introduction of positron emission tomography (PET), followed by functional MR (fMRI), and diffusion tensor imaging (DTI). These advances have led to an appreciation of the critical role that brain abnormalities play in schizophrenia. While structural MRI has proven to be useful in investigating and detecting gray matter abnormalities in schizophrenia, the investigation of white matter has proven to be more challenging as white matter appears homogeneous on conventional MRI and the fibers connecting different brain regions cannot be appreciated. With the development of DTI, we are now able to investigate white matter abnormalities in schizophrenia.

KUBICKI, MAREK; WESTIN, CARL-FREDRIK; McCARLEY, ROBERT W.; SHENTON, MARTHA E.

2009-01-01

223

Different scaling of white matter volume, cortical connectivity, and gyrification across rodent and primate brains.  

PubMed

Expansion of the cortical gray matter in evolution has been accompanied by an even faster expansion of the subcortical white matter volume and by folding of the gray matter surface, events traditionally considered to occur homogeneously across mammalian species. Here we investigate how white matter expansion and cortical folding scale across species of rodents and primates as the gray matter gains neurons. We find very different scaling rules of white matter expansion across the two orders, favoring volume conservation and smaller propagation times in primates. For a similar number of cortical neurons, primates have a smaller connectivity fraction and less white matter volume than rodents; moreover, as the cortex gains neurons, there is a much faster increase in white matter volume and in its ratio to gray matter volume in rodents than in primates. Order-specific scaling of the white matter can be attributed to different scaling of average fiber caliber and neuronal connectivity in rodents and primates. Finally, cortical folding increases as different functions of the number of cortical neurons in rodents and primates, scaling faster in the latter than in the former. While the neuronal rules that govern gray and white matter scaling are different across rodents and primates, we find that they can be explained by the same unifying model, with order-specific exponents. The different scaling of the white matter has implications for the scaling of propagation time and computational capacity in evolution, and calls for a reappraisal of developmental models of cortical expansion in evolution. PMID:23576961

Ventura-Antunes, Lissa; Mota, Bruno; Herculano-Houzel, Suzana

2013-04-09

224

Quantitative MR assessment of structural changes in white matter of children treated for ALL  

NASA Astrophysics Data System (ADS)

Our research builds on the hypothesis that white matter damage resulting from therapy spans a continuum of severity that can be reliably probed using non-invasive MR technology. This project focuses on children treated for ALL with a regimen containing seven courses of high-dose methotrexate (HDMTX) which is known to cause leukoencephalopathy. Axial FLAIR, T1-, T2-, and PD-weighted images were acquired, registered and then analyzed with a hybrid neural network segmentation algorithm to identify normal brain parenchyma and leukoencephalopathy. Quantitative T1 and T2 maps were also analyzed at the level of the basal ganglia and the centrum semiovale. The segmented images were used as mask to identify regions of normal appearing white matter (NAWM) and leukoencephalopathy in the quantitative T1 and T2 maps. We assessed the longitudinal changes in volume, T1 and T2 in NAWM and leukoencephalopathy for 42 patients. The segmentation analysis revealed that 69% of patients had leukoencephalopathy after receiving seven courses of HDMTX. The leukoencephalopathy affected approximately 17% of the patients' white matter volume on average (range 2% - 38%). Relaxation rates in the NAWM were not significantly changed between the 1st and 7th courses. Regions of leukoencephalopathy exhibited a 13% elevation in T1 and a 37% elevation in T2 relaxation rates.

Reddick, Wilburn E.; Glass, John O.; Mulhern, Raymond K.

2001-07-01

225

Distortions in rest-activity rhythm in aging relate to white matter hyperintensities.  

PubMed

Distortions in the rest-activity rhythm in aging are commonly observed. Neurodegenerative changes of the suprachiasmatic nucleus have been proposed to underlie this disrupted rhythm. However, based on previous studies, it can be proposed that white matter hyperintensities (WMH) may also play a role in the altered rest-activity rhythm in aging. The present study focused on the rest-activity rhythm, as assessed with actigraphy, and WMH in nondemented aging. With regard to the rest-activity rhythm, the interdaily stability (IS), intradaily variability (IV) and the amplitude (AMP) of the rhythm were of interest. The white matter hyperintensities were examined separately for the periventricular (PVH) and deep white matter (DWMH) regions, while distinguishing between the various locations within these regions (e.g. occipital PVH). The results indicated that frontal DWMH related to both IS and AMP. A reduction in the most active 10-h period mediated the relationship between frontal DWMH and AMP. Possible underlying mechanisms of these associations are discussed. PMID:17368870

Oosterman, J; van Harten, B; Vogels, R; Gouw, A; Weinstein, H; Scheltens, P; Scherder, E

2007-03-21

226

White matter integrity following traumatic brain injury: the association with severity of injury and cognitive functioning.  

PubMed

Traumatic brain injury (TBI) frequently results in impairments of memory, speed of information processing, and executive functions that may persist over many years. Diffuse axonal injury is one of the key pathologies following TBI, causing cognitive impairments due to the disruption of cortical white matter pathways. The current study examined the association between injury severity, cognition, and fractional anisotropy (FA) following TBI. Two diffusion tensor imaging techniques-region-of-interest tractography and tract-based spatial statistics-were used to assess the FA of white matter tracts. This study examined the comparability of these two approaches as they relate to injury severity and cognitive performance. Sixty-eight participants with mild-to-severe TBI, and 25 healthy controls, underwent diffusion tensor imaging analysis. A subsample of 36 individuals with TBI also completed cognitive assessment. Results showed reduction in FA values for those with moderate and severe TBI, compared to controls and individuals with mild TBI. Although FA tended to be lower for individuals with mild TBI no significant differences were found compared to controls. Information processing speed and executive abilities were most strongly associated with the FA of white matter tracts. The results highlight similarities and differences between region-of-interest tractography and tract-based spatial statistics approaches, and suggest that they may be used together to explore pathology following TBI. PMID:23532465

Spitz, Gershon; Maller, Jerome J; O'Sullivan, Richard; Ponsford, Jennie L

2013-03-27

227

Unified Bundling and Registration of Brain White Matter Fibers  

PubMed Central

Magnetic resonance diffusion tensor imaging is being widely used to reconstruct brain white matter fiber tracts. To characterize structural properties of the tracts, reconstructed fibers are often grouped into bundles that correspond to coherent anatomic structures. For further group analysis of fiber bundles, it is desirable that corresponding bundles from different studies are coregistered. To address these needs simultaneously, a unified fiber bundling and registration (UFIBRE) framework is proposed in this work. The framework is based on maximizing a posteriori Bayesian probabilities using an expectation maximization algorithm. Given a set of segmented template bundles and a whole-brain target fiber set, the UFIBRE algorithm optimally bundles the target fibers and registers them with the template. The bundling component in the UFIBRE algorithm simplifies fiber-based registration into bundle-to-bundle registration, and the registration component in turn guides the bundling process to find bundles consistent with the template. Experiments with in vivo data demonstrate that the estimated bundles have an ?80% consistency with ground truth and the root mean square error between their bundle medial axes is less than one voxel. The proposed algorithm is highly efficient, offering potential routine use for group analysis of white matter fibers.

Xu, Qing; Anderson, Adam W.; Gore, John C.

2011-01-01

228

Individual prediction of white matter injury following traumatic brain injury.  

PubMed

OBJECTIVE: Traumatic brain injury (TBI) often results in traumatic axonal injury (TAI). This can be difficult to identify using conventional imaging. Diffusion tensor imaging (DTI) offers a method of assessing axonal damage in vivo, but has previously mainly been used to investigate groups of patients. Machine learning techniques are increasingly used to improve diagnosis based on complex imaging measures. We investigated whether machine learning applied to DTI data can be used to diagnose white matter damage after TBI and to predict neuropsychological outcome in individual patients. METHODS: We trained pattern classifiers to predict the presence of white matter damage in 25 TBI patients with microbleed evidence of TAI compared to neurologically healthy age-matched controls. We then applied these classifiers to 35 additional patients with no conventional imaging evidence of TAI. Finally, we used regression analyses to predict indices of neuropsychological outcome for information processing speed, executive function, and associative memory in a group of 70 heterogeneous patients. RESULTS: The classifiers discriminated between patients with microbleeds and age-matched controls with a high degree of accuracy, and outperformed other methods. When the trained classifiers were applied to patients without microbleeds, patients having likely TAI showed evidence of greater cognitive impairment in information processing speed and executive function. The classifiers were also able to predict the extent of impairments in information processing speed and executive function. INTERPRETATION: The work provides a proof of principle that multivariate techniques can be used with DTI to provide diagnostic information about clinically significant TAI. ANN NEUROL 2013. PMID:23426980

Hellyer, Peter J; Leech, Robert; Ham, Timothy E; Bonnelle, Valerie; Sharp, David J

2012-11-29

229

Differential Development of Human Brain White Matter Tracts  

PubMed Central

Neuroscience is increasingly focusing on developmental factors related to human structural and functional connectivity. Unfortunately, to date, diffusion-based imaging approaches have only contributed modestly to these broad objectives, despite the promise of diffusion-based tractography. Here, we report a novel data-driven approach to detect similarities and differences among white matter tracts with respect to their developmental trajectories, using 64-direction diffusion tensor imaging. Specifically, using a cross-sectional sample comprising 144 healthy individuals (7 to 48 years old), we applied k-means cluster analysis to separate white matter voxels based on their age-related trajectories of fractional anisotropy. Optimal solutions included 5-, 9- and 14-clusters. Our results recapitulate well-established tracts (e.g., internal and external capsule, optic radiations, corpus callosum, cingulum bundle, cerebral peduncles) and subdivisions within tracts (e.g., corpus callosum, internal capsule). For all but one tract identified, age-related trajectories were curvilinear (i.e., inverted ‘U-shape’), with age-related increases during childhood and adolescence followed by decreases in middle adulthood. Identification of peaks in the trajectories suggests that age-related losses in fractional anisotropy occur as early as 23 years of age, with mean onset at 30 years of age. Our findings demonstrate that data-driven analytic techniques may be fruitfully applied to extant diffusion tensor imaging datasets in normative and neuropsychiatric samples.

Imperati, Davide; Colcombe, Stan; Kelly, Clare; Di Martino, Adriana; Zhou, Juan; Castellanos, F. Xavier; Milham, Michael P.

2011-01-01

230

High Connectivity Between Reduced Cortical Thickness and Disrupted White Matter Tracts in Long-Standing Type 1 Diabetes  

PubMed Central

OBJECTIVE Previous studies have observed disruptions in brain white and gray matter structure in individuals with type 1 diabetes, and these structural differences have been associated with neurocognitive testing deficiencies. This study investigated the relationship between cerebral cortical thickness reductions and white matter microstructural integrity loss in a group of patients with type 1 diabetes and in healthy control subjects using diffusion tensor imaging (DTI). RESEARCH DESIGN AND METHODS Twenty-five subjects with type 1 diabetes for at least 15 years and 25 age- and sex-matched control subjects underwent structural T1 and proton-density and DTI on a 3.0 Tesla scanner. Fractional anisotropy measurements were made on major cerebral white matter tracts, and DTI tractography was performed to identify cortical regions with high connectivity to these tracts. RESULTS Posterior white matter tracts with reduced fractional anisotropy (optic radiations, posterior corona radiata, and the splenium region of the corpus callosum) were found to have high connectivity with a number of posterior cortical regions, including the cuneus, precuneus, fusiform, and posterior parietal cortical regions. A significant reduction in cortical thickness in the diabetic group was observed in the regions with high connectivity to the optic radiations and posterior corona radiata tracts (P < 0.05). CONCLUSIONS The direct relationship between white and gray matter structural pathology has not been previously demonstrated in subjects with long-standing type 1 diabetes. The relationship between posterior white matter microstructural integrity disruption and lower cortical thickness demonstrated using a novel DTI connectivity technique suggests a common or interrelated pathophysiological mechanism in type 1 diabetes.

Franc, Daniel T.; Kodl, Christopher T.; Mueller, Bryon A.; Muetzel, Ryan L.; Lim, Kelvin O.; Seaquist, Elizabeth R.

2011-01-01

231

Quantitative Tract-Based White Matter Development from Birth to Age Two Years  

PubMed Central

Few large-scale studies have been done to characterize the normal human brain white matter growth in the first years of life. We investigated white matter maturation patterns in major fiber pathways in a large cohort of healthy young children from birth to age two using diffusion parameters fractional anisotropy (FA), radial diffusivity (RD) and axial diffusivity (RD). Ten fiber pathways, including commissural, association and projection tracts, were examined with tract-based analysis, providing more detailed and continuous spatial developmental patterns compared to conventional ROI based methods. All DTI data sets were transformed to a population specific atlas with a group-wise longitudinal large deformation diffeomorphic registration approach. Diffusion measurements were analyzed along the major fiber tracts obtained in the atlas space. All fiber bundles show increasing FA values and decreasing radial and axial diffusivities during the development in the first two years of life. The changing rates of the diffusion indices are faster in the first year than the second year for all tracts. RD and FA show larger percentage changes in the first and second years than AD. The gender effects on the diffusion measures are small. Along different spatial locations of fiber tracts, maturation does not always follow the same speed. Temporal and spatial diffusion changes near cortical regions are in general smaller than changes in central regions. Overall developmental patterns revealed in our study confirm the general rules of white matter maturation. This work shows a promising framework to study and analyze white matter maturation in a tract-based fashion. Compared to most previous studies that are ROI-based, our approach has the potential to discover localized development patterns associated with fiber tracts of interest.

Geng, Xiujuan; Gouttard, Sylvain; Sharma, Anuja; Gu, Hongbin; Styner, Martin; Lin, Weili; Gerig, Guido; Gilmore, John H

2012-01-01

232

fMRI Correlates of White Matter Hyperintensities in Late-Life Depression  

PubMed Central

Objective This study tests whether or not the structural white matter lesions that are characteristic of late-life depression are associated with alterations in the functional affective circuits of late-life depression. This study used an emotional faces paradigm that has been shown to engage the affective limbic brain regions. Method Thirty-three elderly depressed patients and 27 nondepressed comparison subjects participated in this study. The patients were recruited through the NIMH-sponsored Advanced Center for Interventions and Services Research for the Study of Late-Life Mood Disorders at the University of Pittsburgh Center for Bioethics and Health Law. Structural and functional MRI was used to assess white matter hyperintensity (WMH) burden and functional magnetic resonance imaging (fMRI) blood-oxygen-level-dependent (BOLD) response on a facial expression affective-reactivity task in both elderly participants with nonpsychotic and non-bipolar major depression (unmedicated) and nondepressed elderly comparison subjects. Results As expected, greater subgenual cingulate activity was observed in the depressed patients relative to the nondepressed comparison subjects. This same region showed greater task-related activity associated with a greater burden of cerebrovascular white matter change in the depressed group. Moreover, the depressed group showed a significantly greater interaction of WMH by fMRI activity effect than the nondepressed group. Conclusions The observation that high WMH burden in late-life depression is associated with greater BOLD response on the affective-reactivity task supports the model that white matter ischemia in elderly depressed patients disrupts brain mechanisms of affective regulation and leads to limbic hyperactivation.

Aizenstein, Howard J.; Andreescu, Carmen; Edelman, Kathryn L.; Cochran, Jennifer L.; Price, Julie; Butters, Meryl A.; Karp, Jordan; Patel, Meenal; Reynolds, Charles F.

2013-01-01

233

Gray and white matter density changes in monozygotic and same-sex dizygotic twins discordant for schizophrenia using voxel-based morphometry  

Microsoft Academic Search

Global gray matter brain tissue volume decreases in schizophrenia have been associated to disease-related (possibly nongenetic) factors. Global white matter brain tissue volume decreases were related to genetic risk factors for the disease. However, which focal gray and white matter brain regions best reflect the genetic and environmental risk factors in the brains of patients with schizophrenia remains unresolved. 1.5-T

Hilleke E. Hulshoff Pol; Hugo G. Schnack; René C. W. Mandl; Rachel G. H. Brans; Neeltje E. M. van Haren; Wim F. C. Baaré; Clarine J. van Oel; D. Louis Collins; Alan C. Evans; René S. Kahn

2006-01-01

234

Quantitative tractography metrics of white matter integrity in diffusion-tensor MRI  

Microsoft Academic Search

We present new quantitative diffusion-tensor imaging (DTI) tractography-based metrics for assessing cerebral white matter integrity. These metrics extend prior work in this area. Tractography models of cerebral white matter were produced from each subject's DTI data. The models are a set of curves (e.g., “streamtubes”) derived from DTI data that represent the underlying topography of the cerebral white matter. Nine

Stephen Correia; Stephanie Y. Lee; Thom Voorn; David F. Tate; Robert H. Paul; Song Zhang; Stephen P. Salloway; Paul F. Malloy; David H. Laidlaw

2008-01-01

235

White Matter Development During Childhood and Adolescence: A Cross-sectional Diffusion Tensor Imaging Study  

Microsoft Academic Search

Maturation of brain white matter pathways is an important factor in cognitive, behavioral, emotional and motor development during childhood and adolescence. In this study, we investigate white matter maturation as reflected by changes in anisotropy and white matter density with age. Thirty-four children and adolescents aged 6--19 years received diffusion-weighted magnetic resonance imag- ing scans. Among these, 30 children and

Naama Barnea-Goraly; Vinod Menon; Mark Eckert; Leanne Tamm; Roland Bammer; Asya Karchemskiy

2005-01-01

236

Surface-Based Analysis on Shape and Fractional Anisotropy of White Matter Tracts in Alzheimer's Disease  

Microsoft Academic Search

BackgroundWhite matter disruption has been suggested as one of anatomical features associated with Alzheimer's disease (AD). Diffusion tensor imaging (DTI), which has been widely used in AD studies, obtains new insights into the white matter structure.MethodsWe introduced surface-based geometric models of the deep white matter tracts extracted from DTI, allowing the characterization of their shape variations relative to an atlas

Anqi Qiu; Kenichi Oishi; Michael I. Miller; Constantine G. Lyketsos; Susumu Mori; Marilyn Albert

2010-01-01

237

Neuropathology of White Matter Changes in Alzheimer’s Disease and Vascular Dementia  

Microsoft Academic Search

Morphological white matter changes were investigated in clinically and neuropathologically diagnosed cases of Alzheimer’s disease (AD; 60 cases) and vascular dementia (VaD; 40 cases). In 33 of 60 AD cases, a white matter disease (WMD) characterized by tissue rarefaction, mild gliosis and a non-amyloid small-vessel sclerosis occurred in the central, preferentially frontal deep white matter. The mean vessel density was

Elisabet Englund

1998-01-01

238

Moderate growth restriction: Deleterious and protective effects on white matter damage  

Microsoft Academic Search

The role for growth restriction in the multifactorial pathophysiology of developing white-matter damage remains debated. We studied rat pups with prenatal growth restriction (GR) induced by unilateral ligation of the uterine artery. Pups with severe GR exhibited white-matter damage that persisted to adulthood [Olivier, P., Baud, O., Evrard, P., Gressens, P.,Verney, C., 2005. Prenatal ischemia and white matter damage in

Paul Olivier; Olivier Baud; Myriam Bouslama; Philippe Evrard; Pierre Gressens; Catherine Verneya

2007-01-01

239

Cerebral White Matter Integrity Mediates Adult Age Differences in Cognitive Performance  

Microsoft Academic Search

Previous research has established that age-related decline oc- curs in measures of cerebral white matter integrity, but the role of this decline in age-related cognitive changes is not clear. To conclude that white matter integrity has a mediating (causal) con- tribution, it is necessary to demonstrate that statistical control of the white matter-cognition relation reduces the magnitude of age-cognition relation.

David J. Madden; Julia Spaniol; Matthew C. Costello; Barbara Bucur; Leonard E. White; Roberto Cabeza; Simon W. Davis; Nancy A. Dennis; James M. Provenzale; Scott A. Huettel

2009-01-01

240

Singularities in diffusion tensor fields and their relevance in white matter fiber tractography.  

PubMed

The technique of diffusion tensor tractography utilizes directions of maximum diffusion to reconstruct pathways of white matter structures in the brain. Critically, successful tracking of these white matter pathways depends on well-defined maximal diffusion directional information. By examination of diffusion tensor field properties in the human brain, we demonstrate that the geometry of tracked pathways is influenced by points in the field where the maximum diffusion direction is poorly defined. In common with tensor fields describing other mathematical and physical phenomena, such as 3D surface differential geometry and gravitational fields, we refer to these points as singularities. Here we describe an automated procedure for detecting singularities and demonstrate that these occur where there is (i) fiber crossing, (ii) pathways passing close to one another within a voxel (partial volume effect), and (iii) noise propagation into low anisotropy regions. In order to highlight the relevance of singularities in tracking white matter structures, we determined their effect on computation of the cortico-spinal pathway. PMID:15193577

Barrick, Thomas R; Clark, Chris A

2004-06-01

241

Motor Dysfunction Correlates with Frontal White Matter Ischemic Changes in Patients with Leukoaraiosis  

PubMed Central

Objectives. To test the relation between white matter lesions (WML) location and physical performance, in aged patients. Methods. Subjects: 29 patients (17 males), aged >65 (mean age 72.6 ± 5.2), with leukoaraiosis. WML was quantified with a visual scale; Apparent Diffusion Coefficient (ADC) was measured bilaterally in frontal periventricular lesioned white matter and frontal and parieto-occipital normal appearing white matter (NAWM). Motor performance was studied using the Short Physical Performance Battery (SPPB), single leg stand time, finger tapping and grooved pegboard tests (GPT). Results. There were significant correlations between the frontal region visual scale scores and SPPB chair stands (r = ?0.379; P = .039) and Grooved Pegboard (r = 0.393; P = .032); frontal NAWM ADC values and SPPB standing balance (r = ?0.450; P = .014) and SPPB 4 meter walk (r = ?0.379; P = .043). Conclusion. Frontal WML are negatively related to motor performance in patients with leukoaraiosis. DWI results suggest that this may be true even for NAWM.

Viana-Baptista, Miguel; Bugalho, Paulo; Jordao, Constanca; Ribeiro, Olga; Esperanca-Pina, Jose Antonio; Ferro, Jose

2011-01-01

242

White matter abnormalities in skin picking disorder: a diffusion tensor imaging study.  

PubMed

Skin picking disorder (SPD) is characterized by the repetitive and compulsive picking of skin, resulting in tissue damage. Neurocognitive findings in SPD implicate difficulty with response inhibition (suppression of pre-potent motor responses). This function is dependent on the integrity of the right frontal gyrus and the anterior cingulate cortices, and white-matter tracts connecting such neural nodes. It was hypothesized that SPD would be associated with reduced fractional anisotropy in regions implicated in top-down response suppression, particularly white-matter tracts in proximity of the bilateral anterior cingulate and right frontal (especially orbitofrontal and inferior frontal) cortices. 13-subjects meeting proposed SPD criteria for DSM-5 free from other current psychiatric comorbidities, and 12 healthy comparison subjects underwent MRI with a 3-T system. Between-group comparisons of imaging data underwent voxelwise analysis with permutation modeling and cluster correction. Fractional anisotropy (measured using diffusion tensor imaging) was the primary outcome measure. Subjects with SPD exhibited significantly reduced fractional anisotropy in tracts distributed bilaterally, which included the anterior cingulate cortices. Fractional anisotropy did not correlate significantly with SPD disease severity, or depressive or anxiety scores. These findings implicate disorganization of white-matter tracts involved in motor generation and suppression in the pathophysiology of SPD, findings remarkably similar to those previously reported in trichotillomania. This study adds considerable support to the notion that-in addition to the phenomenological and comorbid overlap between SPD and trichotillomania-these disorders likely share overlapping neurobiology. PMID:23303052

Grant, Jon E; Odlaug, Brian L; Hampshire, Adam; Schreiber, Liana R N; Chamberlain, Samuel R

2012-11-29

243

In vivo parahippocampal white matter pathology as a biomarker of disease progression to Alzheimer's disease.  

PubMed

Noninvasive diagnostic tests for Alzheimer's disease (AD) are limited. Postmortem diagnosis is based on density and distribution of neurofibrillary tangles (NFTs) and amyloid-rich neuritic plaques. In preclinical stages of AD, the cells of origin for the perforant pathway within the entorhinal cortex are among the first to display NFTs, indicating its compromise in early stages of AD. We used diffusion tensor imaging (DTI) to assess the integrity of the parahippocampal white matter in mild cognitive impairment (MCI) and AD, as a first step in developing a noninvasive tool for early diagnosis. Subjects with AD (N = 9), MCI (N = 8), or no cognitive impairment (NCI; N = 20) underwent DTI-MRI. Fractional anisotropy (FA) and mean (MD) and radial (RD) diffusivity measured from the parahippocampal white matter in AD and NCI subjects differed greatly. Discriminant analysis in the MCI cases assigned statistical membership of 38% of MCI subjects to the AD group. Preliminary data 1 year later showed that all MCI cases assigned to the AD group either met the diagnostic criteria for probable AD or showed significant cognitive decline. Voxelwise analysis in the parahippocampal white matter revealed a progressive change in the DTI patterns in MCI and AD subjects: whereas converted MCI cases showed structural changes restricted to the anterior portions of this region, in AD the pathology was generalized along the entire anterior-posterior axis. The use of DTI for in vivo assessment of the parahippocampal white matter may be useful for identifying individuals with MCI at highest risk for conversion to AD and for assessing disease progression. J. Comp. Neurol. 521:4300-4317, 2013. © 2013 Wiley Periodicals, Inc. PMID:23839862

Solodkin, Ana; Chen, E Elinor; Van Hoesen, Gary W; Heimer, Lennart; Shereen, Ahmed; Kruggel, Frithjof; Mastrianni, James

2013-12-15

244

White Matter Asymmetry in the Human Brain: A Diffusion Tensor MRI Study  

Microsoft Academic Search

Language ability and handedness are likely to be associated with asymmetry of the cerebral cortex (grey matter) and connectivity (white matter). Grey matter asymmetry, most likely linked to language has been identified with voxel-based morphometry (VBM) using T1-weighted images. Differences in white matter obtained with this technique are less consistent, probably due to the relative insen- sitivity of the T1

C. Buchel; T. Raedler; M. Sommer; M. Sach; C. Weiller; M. A. Koch

2004-01-01

245

Roles of white matter in central nervous system pathophysiologies  

PubMed Central

The phylogenetic enlargement of cerebral cortex culminating in the human brain imposed greater communication needs that have been met by the massive expansion of WM (white matter). Damage to WM alters brain function, and numerous neurological diseases feature WM involvement. In the current review, we discuss the major features of WM, the contributions of WM compromise to brain pathophysiology, and some of the mechanisms mediating WM injury. We will emphasize the newly appreciated importance of neurotransmitter signalling in WM, particularly glutamate and ATP signalling, to understanding both normal and abnormal brain functions. A deeper understanding of the mechanisms leading to WM damage will generate much-needed insights for developing therapies for acute and chronic diseases with WM involvement.

Matute, Carlos; Ransom, Bruce R

2012-01-01

246

Brain virtual dissection and white matter 3D visualization.  

PubMed

This paper presents an immersive visualization tool that helps anatomists to establish a ground truth for brain white matter fiber bundles. Each step of a progressive anatomical dissection of human brain hemisphere is acquired using a high resolution 3D laser scanner and a photographic device. Each resulting surface is textured with a high resolution image and registered into a common 3D space using fiducial landmarks. Surfaces can be visualized using stereoscopic hardware and are interactively selectable. The tool allows the user to identify specific fiber bundle parts. Extracted fiber bundles are stacked together and rendered in stereoscopy with the corresponding MR volume. Surgeons have validated this tool for creating ground truth in medical imaging with the perspective of validating tractography algorithms. PMID:23400190

Serres, Barthélemy; Zemmoura, Ilyess; Andersson, Frédéric; Tauber, Clovis; Destrieux, Christophe; Venturini, Gilles

2013-01-01

247

Detection of white matter lesions in cerebral small vessel disease  

NASA Astrophysics Data System (ADS)

White matter lesions (WML) are diffuse white matter abnormalities commonly found in older subjects and are important indicators of stroke, multiple sclerosis, dementia and other disorders. We present an automated WML detection method and evaluate it on a dataset of small vessel disease (SVD) patients. In early SVD, small WMLs are expected to be of importance for the prediction of disease progression. Commonly used WML segmentation methods tend to ignore small WMLs and are mostly validated on the basis of total lesion load or a Dice coefficient for all detected WMLs. Therefore, in this paper, we present a method that is designed to detect individual lesions, large or small, and we validate the detection performance of our system with FROC (free-response ROC) analysis. For the automated detection, we use supervised classification making use of multimodal voxel based features from different magnetic resonance imaging (MRI) sequences, including intensities, tissue probabilities, voxel locations and distances, neighborhood textures and others. After preprocessing, including co-registration, brain extraction, bias correction, intensity normalization, and nonlinear registration, ventricle segmentation is performed and features are calculated for each brain voxel. A gentle-boost classifier is trained using these features from 50 manually annotated subjects to give each voxel a probability of being a lesion voxel. We perform ROC analysis to illustrate the benefits of using additional features to the commonly used voxel intensities; significantly increasing the area under the curve (Az) from 0.81 to 0.96 (p<0.05). We perform the FROC analysis by testing our classifier on 50 previously unseen subjects and compare the results with manual annotations performed by two experts. Using the first annotator results as our reference, the second annotator performs at a sensitivity of 0.90 with an average of 41 false positives per subject while our automated method reached the same level of sensitivity at approximately 180 false positives per subject.

Riad, Medhat M.; Platel, Bram; de Leeuw, Frank-Erik; Karssemeijer, Nico

2013-02-01

248

Assessing prenatal white matter connectivity in commissural agenesis.  

PubMed

Complete or partial agenesis of the corpus callosum are rather common developmental abnormalities, resulting in a wide spectrum of clinical neurodevelopmental deficits. Currently, a significant number of these cases are detected by prenatal sonography during second trimester screening examinations. However, major uncertainties about a detailed morphological diagnosis and the clinical significance do not allow accurate prenatal counselling. Here, we were able to demonstrate the 3D connectivity of aberrant commissural tracts in 16 cases with complete and four cases with partial callosal agenesis using the foetal magnetic resonance imaging techniques of diffusion tensor imaging and tractography in utero and in vivo between gestational weeks 20 and 37. The 'misguided' pre-myelinated callosal axons that represent the bundle of Probst were non-invasively visualized, and they showed a degree of structural integrity similar to that of the callosal pathways of age-matched foetuses without cerebral pathologies. In two foetuses, we were able to prove, by post-mortem histology, that diffusion tensor imaging allows the depiction of the bundle of Probst, even during early stages of pre-myelination at 20 and 22 gestational weeks. In cases with partial callosal agenesis, an aberrant sigmoid-shaped bundle was prenatally depicted, confirming the findings of heterotopic interhemispheric connectivity in adults with partial callosal agenesis. In addition to the corpus callosum, other white matter pathways were also involved, including somatosensory and motor pathways that showed significantly higher fractional anisotropy values in cases with callosal agenesis compared with control subjects. A detailed prenatal assessment of abnormal white matter connectivity in cases of midline anomalies will help to explain and understand the clinical heterogeneity in these cases, taking future foetal neurological counselling strategies to a new level. PMID:23365096

Kasprian, Gregor; Brugger, Peter C; Schöpf, Veronika; Mitter, Christian; Weber, Michael; Hainfellner, Johannes A; Prayer, Daniela

2013-01-01

249

Endothelial Function and White Matter Hyperintensities in Older Adults With Cardiovascular Disease  

PubMed Central

Background and Purpose The presence of white matter hyperintensities on brain MRI is common among elderly individuals. Previous research suggests that cardiovascular risk factors are associated with increased white matter hyperintensities. Examining the role of direct physiological measures of vascular function will help to clarify the vascular mechanisms related to white matter hyperintensities. The aim of the present study was to examine the association between endothelial-dependent and endothelial-independent vasodilatation and white matter hyperintensity volume. Methods Twenty-five older adults with a range of cardiovascular diseases underwent brain MRI and completed assessments of blood vessel integrity using endothelial-dependent and independent flow-mediated dilation of the brachial artery. A semi-automated pixel-based method was used to quantify total brain volume and white matter hyperintensity volume, with white matter hyperintensity volume corrected for total brain volume. The association between measures of flow-mediated dilation and log-transformed white matter hyperintensities was examined. Results Correlation analysis revealed that endothelial-dependent vasodilatation was significantly and inversely associated with white matter hyperintensity volume. In contrast, endothelial-independent vasodilatation was not associated with white matter hyperintensities. Neither endothelial-dependent nor endothelial-independent vasodilatation was associated with total brain volume. Conclusions These data provide preliminary evidence that the integrity of the vascular endothelium is associated with white matter hyperintensities in older adults with cardiovascular disease. Impaired vascular function may be one mechanism that contributes to the development of white matter hyperintensities in the brain. Additional longitudinal research combining measures of vessel function, neuroimaging and cognition will be helpful in clarifying this potential mechanism.

Hoth, Karin F.; Tate, David F.; Poppas, Athena; Forman, Daniel E.; Gunstad, John; Moser, David J.; Paul, Robert H.; Jefferson, Angela L.; Haley, Andreana P.; Cohen, Ronald A.

2009-01-01

250

Magnetic resonance imaging of differential gray versus white matter injury following a mild or moderate hypoxic-ischemic insult in neonatal rats.  

PubMed

Selective white matter injury in the pre-mature infants suggests it has a greater susceptibility to hypoxia-ischemia. To investigate whether white matter injury would predominate following a mild hypoxic-ischemic insult, 7-day-old rats underwent either mild or moderate hypoxia-ischemia and magnetic resonance imaging 24 h later. Mild and moderate hypoxia-ischemia were produced by unilateral carotid artery occlusion plus exposure to hypoxia for either 45-50 or 90 min at ambient temperatures of 34.5 or 35.5 degrees C, respectively. Following mild hypoxia-ischemia, there was a significant increase in T(1) and T(2) within periventricular white matter (e.g. corpus callosum) in the hemisphere ipsilateral to the occlusion compared to that contralaterally and less of an increase within gray matter (e.g. cortex and striatum). This corresponded to relatively selective white matter injury detected histologically. Following a moderate hypoxia-ischemia, both gray and white matter was severely injured with marked increases in T(1) and T(2) occurring in both white and gray matter regions ipsilateral to the hypoxia-ischemia. We conclude that a mild insult, consisting of a short duration of hypoxia-ischemia at a slightly lower body temperature than a moderate hypoxic-ischemic insult, produces enhanced injury in white matter and a relative sparing of gray matter. PMID:15364422

Qiao, Min; Meng, Shuzhen; Scobie, Kathryn; Foniok, Tadeusz; Tuor, Ursula I

2004-09-30

251

Limitations on the Developing Preterm Brain: Impact of Periventricular White Matter Lesions on Brain Connectivity and Cognition  

ERIC Educational Resources Information Center

|Brain lesions to the white matter in peritrigonal regions, periventricular leukomalacia, in children who were born prematurely represent an important model for studying limitations on brain development. The lesional pattern is of early origin and bilateral, that constrains the compensatory potential of the brain. We suggest that (i) topography…

Pavlova, Marina A.; Krageloh-Mann, Ingeborg

2013-01-01

252

Analysis of Normal-Appearing White Matter in Multiple Sclerosis: Comparison of Diffusion Tensor MR Imaging and Magnetization Transfer Imaging  

Microsoft Academic Search

BACKGROUND AND PURPOSE: Our purpose was to compare diffusion tensor MR and magnetization transfer imaging in assessing normal-appearing white matter (WM) regions in multiple sclerosis (MS). METHODS: Diffusion tensor, magnetization transfer, and conventional MR imaging were performed in 12 patients with MS. Fractional anisotropy, apparent diffusion coefficients (ADCs), and magnetization transfer ratios (MTRs) were measured in plaques, normal-appear- ing periplaque

Alexander C. Guo; Valerie L. Jewells; James M. Provenzale

2001-01-01

253

Microstructural white matter changes in normal aging: A diffusion tensor imaging study with higher-order polynomial regression models  

Microsoft Academic Search

Diffusion tensor imaging (DTI) has already proven to be a valuable tool when investigating both global and regional microstructural white matter (WM) brain changes in the human aging process. Although subject to many criticisms, voxel-based analysis is currently one of the most common and preferred approaches in such DTI aging studies. In this context, voxel-based DTI analyses have assumed a

Jung-Lung Hsu; Wim Van Hecke; Chyi-Huey Bai; Cheng-Hui Lee; Yuh-Feng Tsai; Hou-Chang Chiu; Fu-Shan Jaw; Chien-Yeh Hsu; Jyu-Gang Leu; Wei-Hung Chen; Alexander Leemans

2010-01-01

254

White matter integrity correlates of implicit sequence learning in healthy aging.  

PubMed

Previous research has identified subcortical (caudate, putamen, hippocampus) and cortical (dorsolateral prefrontal cortex, DLPFC; frontal motor areas) regions involved in implicit sequence learning, with mixed findings for whether these neural substrates differ with aging. The present study used diffusion tensor imaging (DTI) tractography to reconstruct white matter connections between the known gray matter substrates, and integrity of these tracts was related to learning in the alternating serial reaction time task (ASRT) in younger and healthy older adults. Both age groups showed significant sequence learning (better performance to predictable, frequently occurring vs. less frequent events), with an age-related difference in the late learning stage. Caudate-DLPFC and hippocampus-DLPFC tract integrity were related to ASRT sequence learning, and these brain-behavior relationships did not differ significantly between age groups. Additionally, age-related decreases in caudate-DLPFC tract integrity mediated age-related differences in late stage sequence learning. Together, these findings complement studies of gray matter substrates underlying implicit sequence learning, and provide evidence for similar white matter integrity-sequence learning relationships in younger and healthy older adults. PMID:20452099

Bennett, Ilana J; Madden, David J; Vaidya, Chandan J; Howard, James H; Howard, Darlene V

2010-05-07

255

Alexithymia and reduced white matter integrity in schizophrenia: a diffusion tensor imaging study on impaired emotional self-awareness.  

PubMed

Alexithymia is characterized by deficits in emotional self-awareness. A number of previous studies have revealed impaired emotional self-awareness in schizophrenia. Although the pathology of schizophrenia is thought to involve disrupted white matter integrity, its relationship with alexithymia remains unclear. The present study investigated associations between alexithymia and white matter integrity, to seek the neural basis of impaired emotional self-awareness in schizophrenia. Forty-four patients with schizophrenia and 44 age-, gender- and predicted IQ level-matched healthy controls underwent diffusion-weighted imaging. Alexithymia was assessed using the 20-item Toronto Alexithymia Scale (TAS-20). We applied tract-based spatial statistics to investigate the correlation between the TAS-20 total score and white matter fractional anisotropy (FA). TAS-20 scores were significantly higher in patients than in controls. In the patient group only, FA was negatively correlated with the TAS-20 total score in the corpus callosum, mostly the left part of the superior and inferior longitudinal fasciculi, the inferior occipito-frontal fasciculus, the anterior and posterior thalamic radiation, and the precuneus white matter. These results suggest that schizophrenia is associated with alexithymia, and that reduced white matter integrity within these regions constitutes an important pathology underlying impaired self-emotional awareness in schizophrenia. PMID:22986045

Kubota, Manabu; Miyata, Jun; Sasamoto, Akihiko; Kawada, Ryosaku; Fujimoto, Shinsuke; Tanaka, Yusuke; Sawamoto, Nobukatsu; Fukuyama, Hidenao; Takahashi, Hidehiko; Murai, Toshiya

2012-09-15

256

White matter tract signatures of the progressive aphasias.  

PubMed

The primary progressive aphasias (PPA) are a heterogeneous group of language-led neurodegenerative diseases resulting from large-scale brain network degeneration. White matter (WM) pathways bind networks together, and might therefore hold information about PPA pathogenesis. Here we used diffusion tensor imaging and tract-based spatial statistics to compare WM tract changes between PPA syndromes and with respect to Alzheimer's disease and healthy controls in 33 patients with PPA (13 nonfluent/agrammatic PPA); 10 logopenic variant PPA; and 10 semantic variant PPA. Nonfluent/agrammatic PPA was associated with predominantly left-sided and anterior tract alterations including uncinate fasciculus (UF) and subcortical projections; semantic variant PPA with bilateral alterations in inferior longitudinal fasciculus and UF; and logopenic variant PPA with bilateral but predominantly left-sided alterations in inferior longitudinal fasciculus, UF, superior longitudinal fasciculus, and subcortical projections. Tract alterations were more extensive than gray matter alterations, and the extent of alteration across tracts and PPA syndromes varied between diffusivity metrics. These WM signatures of PPA syndromes illustrate the selective vulnerability of brain language networks in these diseases and might have some pathologic specificity. PMID:23312804

Mahoney, Colin J; Malone, Ian B; Ridgway, Gerard R; Buckley, Aisling H; Downey, Laura E; Golden, Hannah L; Ryan, Natalie S; Ourselin, Sebastien; Schott, Jonathan M; Rossor, Martin N; Fox, Nick C; Warren, Jason D

2013-01-09

257

White matter tract signatures of the progressive aphasias  

PubMed Central

The primary progressive aphasias (PPA) are a heterogeneous group of language-led neurodegenerative diseases resulting from large-scale brain network degeneration. White matter (WM) pathways bind networks together, and might therefore hold information about PPA pathogenesis. Here we used diffusion tensor imaging and tract-based spatial statistics to compare WM tract changes between PPA syndromes and with respect to Alzheimer's disease and healthy controls in 33 patients with PPA (13 nonfluent/agrammatic PPA); 10 logopenic variant PPA; and 10 semantic variant PPA. Nonfluent/agrammatic PPA was associated with predominantly left-sided and anterior tract alterations including uncinate fasciculus (UF) and subcortical projections; semantic variant PPA with bilateral alterations in inferior longitudinal fasciculus and UF; and logopenic variant PPA with bilateral but predominantly left-sided alterations in inferior longitudinal fasciculus, UF, superior longitudinal fasciculus, and subcortical projections. Tract alterations were more extensive than gray matter alterations, and the extent of alteration across tracts and PPA syndromes varied between diffusivity metrics. These WM signatures of PPA syndromes illustrate the selective vulnerability of brain language networks in these diseases and might have some pathologic specificity.

Mahoney, Colin J.; Malone, Ian B.; Ridgway, Gerard R.; Buckley, Aisling H.; Downey, Laura E.; Golden, Hannah L.; Ryan, Natalie S.; Ourselin, Sebastien; Schott, Jonathan M.; Rossor, Martin N.; Fox, Nick C.; Warren, Jason D.

2013-01-01

258

White Matter Atrophy and Cognitive Dysfunctions in Neuromyelitis Optica  

PubMed Central

Neuromyelitis optica (NMO) is an inflammatory disease of central nervous system characterized by optic neuritis and longitudinally extensive acute transverse myelitis. NMO patients have cognitive dysfunctions but other clinical symptoms of brain origin are rare. In the present study, we aimed to investigate cognitive functions and brain volume in NMO. The study population consisted of 28 patients with NMO and 28 healthy control subjects matched for age, sex and educational level. We applied a French translation of the Brief Repeatable Battery (BRB-N) to the NMO patients. Using SIENAx for global brain volume (Grey Matter, GM; White Matter, WM; and whole brain) and VBM for focal brain volume (GM and WM), NMO patients and controls were compared. Voxel-level correlations between diminished brain concentration and cognitive performance for each tests were performed. Focal and global brain volume of NMO patients with and without cognitive impairment were also compared. Fifteen NMO patients (54%) had cognitive impairment with memory, executive function, attention and speed of information processing deficits. Global and focal brain atrophy of WM but not Grey Matter (GM) was found in the NMO patients group. The focal WM atrophy included the optic chiasm, pons, cerebellum, the corpus callosum and parts of the frontal, temporal and parietal lobes, including superior longitudinal fascicle. Visual memory, verbal memory, speed of information processing, short-term memory and executive functions were correlated to focal WM volumes. The comparison of patients with, to patients without cognitive impairment showed a clear decrease of global and focal WM, including brainstem, corticospinal tracts, corpus callosum but also superior and inferior longitudinal fascicles. Cognitive impairment in NMO patients is correlated to the decreased of global and focal WM volume of the brain. Further studies are needed to better understand the precise origin of cognitive impairment in NMO patients, particularly in the WM.

Blanc, Frederic; Noblet, Vincent; Jung, Barbara; Rousseau, Francois; Renard, Felix; Bourre, Bertrand; Longato, Nadine; Cremel, Nadjette; Di Bitonto, Laure; Kleitz, Catherine; Collongues, Nicolas; Foucher, Jack; Kremer, Stephane; Armspach, Jean-Paul; de Seze, Jerome

2012-01-01

259

Depressive Symptoms in Adolescents: Associations with White Matter Volume and Marijuana Use  

ERIC Educational Resources Information Center

|Background: Depressed mood has been associated with decreased white matter and reduced hippocampal volumes. However, the relationship between brain structure and mood may be unique among adolescents who use marijuana heavily. The goal of this study was to examine the relationship between white matter and hippocampal volumes and depressive…

Medina, Krista Lisdahl; Nagel, Bonnie J.; Park, Ann; McQueeny, Tim; Tapert, Susan F.

2007-01-01

260

The Effect of White Matter Low Attenuation on Cognitive Performance in Dementia of the Alzheimer Type  

Microsoft Academic Search

Summary The effect of leukoaraiosis or white matter low attenuation (WMLA) on cognitive function is not fully understood. We compared the neuropsychological performance of 37 Alzheimer's disease patients with WMLA on CT brain scans with a similar group of 31 Alzheimer's disease patients with no evidence of white matter lesions. Patients with WMLA performed significantly worse on tests of visuospatial

K. AMAR; R. S. BUCKS; T. LEWIS; M. SCOTT; G. K. WILCOCK

1996-01-01

261

Perinatal White Matter Injury: The Changing Spectrum of Pathology and Emerging Insights into Pathogenetic Mechanisms  

ERIC Educational Resources Information Center

|Perinatal brain injury in survivors of premature birth has a unique and unexplained predilection for periventricular cerebral white matter. Periventricular white-matter injury (PWMI) is now the most common cause of brain injury in preterm infants and the leading cause of chronic neurological morbidity. The spectrum of chronic PWMI includes focal…

Back, Stephen A.

2006-01-01

262

DTI and MTR abnormalities in schizophrenia: Analysis of white matter integrity  

Microsoft Academic Search

Diffusion tensor imaging (DTI) studies in schizophrenia demonstrate lower anisotropic diffusion within white matter due either to loss of coherence of white matter fiber tracts, to changes in the number and\\/or density of interconnecting fiber tracts, or to changes in myelination, although methodology as well as localization of such changes differ between studies. The aim of this study is to

M. Kubicki; C. F. Westin; P. G. Nestor; R. V. Mulkern; S. E. Maier; M. Niznikiewicz; E. E. Connor; J. J. Levitt; M. Frumin; R. Kikinis; F. A. Jolesz; R. W. McCarley; M. E. Shenton

2005-01-01

263

Diffusion tensor imaging: serial quantitation of white matter tract maturity in premature newborns  

Microsoft Academic Search

Magnetic resonance diffusion tensor imaging (DTI) enables the discrimination of white matter pathways before myelination is evident histologically or on conventional MRI. In this investigation, 14 premature neonates with no evidence of white matter abnormalities by conventional MRI were studied with DTI. A custom MR-compatible incubator with a novel high sensitivity neonatal head coil and improved acquisition and processing techniques

Savannah C. Partridge; Pratik Mukherjee; Roland G. Henry; Steven P. Miller; Jeffrey I. Berman; Hua Jin; Ying Lu; Orit A. Glenn; Donna M. Ferriero; A. James Barkovich; Daniel B Vigneron

2004-01-01

264

Ultrastructural Hippocampal and White Matter Alterations in Mild Cognitive Impairment: A Diffusion Tensor Imaging Study  

Microsoft Academic Search

Mild cognitive impairment (MCI) is considered to be a transitional stage between normal aging and dementia. In Alzheimer’s disease (AD), white matter structural pathology is due to Wallerian degeneration and central angiopathy. However, in MCI patients, the presence and extent of white matter alterations as a possible correlate of impaired memory function and as predictor of subsequent progression to AD

Andreas Fellgiebel; Paulo Wille; Matthias J. Müller; Georg Winterer; Armin Scheurich; Goran Vucurevic; Lutz G. Schmidt; Peter Stoeter

2004-01-01

265

Cigarette smoking is associated with reduced microstructural integrity of cerebral white matter  

Microsoft Academic Search

Cigarette smoking doubles the risk of dementia and Alzheimer's disease. Various pathophysiological pathways have been proposed to cause such a cognitive decline, but the exact mechanisms remain unclear. Smoking may affect the microstructural integrity of cerebral white matter. Diffusion tensor imaging is known to be sensitive for microstructural changes in cerebral white matter. We therefore cross-sectionally studied the relation between

R. A. R. Gons; A. G. W. van Norden; K. F. de Laat; L. J. van Oudheusden; I. W. M. van Uden; M. P. Zwiers; D. G. Norris; F. E. de Leeuw

2011-01-01

266

Altered White Matter Microstructure in Children with Attention-Deficit/Hyperactivity Disorder  

ERIC Educational Resources Information Center

|Objective: Identification of biomarkers is a priority for attention-deficit/hyperactivity disorder (ADHD). Studies have documented macrostructural brain alterations in ADHD, but few have examined white matter microstructure, particularly in preadolescent children. Given dramatic white matter maturation across childhood, microstructural…

Nagel, Bonnie J.; Bathula, Deepti; Herting, Megan; Schmitt, Colleen; Kroenke, Christopher D.; Fair, Damien; Nigg, Joel T.

2011-01-01

267

Growth of White Matter in the Adolescent Brain: Myelin or Axon?  

ERIC Educational Resources Information Center

|White matter occupies almost half of the human brain. It contains axons connecting spatially segregated modules and, as such, it is essential for the smooth flow of information in functional networks. Structural maturation of white matter continues during adolescence, as reflected in age-related changes in its volume, as well as in its…

Paus, Tomas

2010-01-01

268

White Matter Integrity and Pictorial Reasoning in High-Functioning Children with Autism  

ERIC Educational Resources Information Center

|The current study investigated the neurobiological role of white matter in visuospatial versus linguistic processing abilities in autism using diffusion tensor imaging. We examined differences in white matter integrity between high-functioning children with autism (HFA) and typically developing controls (CTRL), in relation to the groups' response…

Sahyoun, Cherif P.; Belliveau, John W.; Mody, Maria

2010-01-01

269

Do white matter changes on MRI and CT differentiate vascular dementia from Alzheimer's disease?  

Microsoft Academic Search

MRI showed white matter changes in all 29 patients with vascular dementia and in eight out of 22 patients with Alzheimer's disease. The corresponding figures for CT were 26 and 1, respectively. White matter changes are therefore a useful diagnostic aid in the differential diagnosis between vascular dementia and Alzheimer's disease.

T Erkinjuntti; L Ketonen; R Sulkava; J Sipponen; M Vuorialho; M Iivanainen

1987-01-01

270

White matter maturation in visual and motor areas predicts the latency of visual activation in children.  

PubMed

In humans, white matter maturation is important for the improvement of cognitive function and performance with age. Across studies the variables of white matter maturity and age are highly correlated; however, the unique contributions of white matter to information processing speed remain relatively unknown. We investigated the relations between the speed of the visually-evoked P100m response and the biophysical properties of white matter in 11 healthy children performing a simple, visually-cued finger movement. We found that: (1) the latency of the early, visually-evoked response was related to the integrity of white matter in both visual and motor association areas and (2) white matter maturation in these areas accounted for the variations in visual processing speed, independent of age. Our study is a novel investigation of spatial-temporal dynamics in the developing brain and provides evidence that white matter maturation accounts for age-related decreases in the speed of visual response. Developmental models of cortical specialization should incorporate the unique role of white matter maturation in mediating changes in performance during tasks involving visual processing. PMID:21432944

Dockstader, Colleen; Gaetz, William; Rockel, Conrad; Mabbott, Donald J

2011-03-22

271

Diffusion tensor imaging of adult age differences in cerebral white matter: relation to response time  

Microsoft Academic Search

Diffusion tensor imaging (DTI) measures the displacement of water molecules across tissue components, thus providing information regarding the microstructure of cerebral white matter. Fractional anisotropy (FA), the degree to which diffusion is directionally dependent, is typically higher for compact, homogeneous fiber bundles such as the corpus callosum. Previous DTI studies in adults have demonstrated an age-related decline in white matter

David J. Madden; Wythe L. Whiting; Scott A. Huettel; Leonard E. White; James R. MacFall; James M. Provenzalee

2004-01-01

272

White Matter Changes on CT and MRI: An Overview of Visual Rating Scales  

Microsoft Academic Search

Since the recognition of white matter changes on CT (leukoaraiosis), rating scales for the location and severity of white matter changes have been developed, mainly for research purposes, to investigate factors such as the relation with cognition, risk factors, and pathology. The main purpose of rating scales is to provide scores that can be used in statistical analyses. The development

Philip Scheltens; Timo Erkinjunti; Didier Leys; Lars-Olaf Wahlund; Domenico Inzitari; Theodoro del Ser; Florence Pasquier; Frederik Barkhof; Riita Mäntylä; John Bowler; Anders Wallin; Joseph Ghika; Franz Fazekas; Leonardo Pantoni

1998-01-01

273

State-related changes in cerebral white matter may underlie psychosis exacerbation  

Microsoft Academic Search

Previous reports have described accelerated loss of cerebral white matter in schizophrenia. Others have reported changes of ventricle volumes in schizophrenic patients, with greatest increases following remission of psychotic symptoms. In this study changes in cerebral white matter volumes and psychotic symptoms were measured in 16 recently decompensated schizophrenic patients from neuroleptic-free baseline to 4 weeks later during treatment with

James Christensen; Jennifer Holcomb; David L. Garver

2004-01-01

274

White Matter Lesions and Brain Atrophy: More than Shared Risk Factors? A Systematic Review  

Microsoft Academic Search

Background: White matter lesions (WML) and brain atrophy are often found on MRI in the elderly. Shared vascular risk factors may be an explanation for their concomitance. However, disturbances of white matter integrity could also be involved in the pathogenesis of brain atrophy. Our objective was to systematically review studies that investigated the relation between WML and brain atrophy on

Auke P. A. Appelman; Lieza G. Exalto; Yolanda van der Graaf; Geert Jan Biessels; Willem P. T. M. Mali; Mirjam I. Geerlings

2009-01-01

275

Growth of white matter in the adolescent brain: Myelin or axon?  

Microsoft Academic Search

White matter occupies almost half of the human brain. It contains axons connecting spatially segregated modules and, as such, it is essential for the smooth flow of information in functional networks. Structural maturation of white matter continues during adolescence, as reflected in age-related changes in its volume, as well as in its microstructure. Here I review recent observations obtained with

Tomáš Paus

2010-01-01

276

The dimensionality of between-person differences in white matter microstructure in old age.  

PubMed

Between-person differences in white matter microstructure may partly generalize across the brain and partly play out differently for distinct tracts. We used diffusion-tensor imaging and structural equation modeling to investigate this issue in a sample of 260 adults aged 60-87 years. Mean fractional anisotropy and mean diffusivity of seven white matter tracts in each hemisphere were quantified. Results showed good fit of a model positing that individual differences in white matter microstructure are structured according to tracts. A general factor, although accounting for variance in the measures, did not adequately represent the individual differences. This indicates the presence of a substantial amount of tract-specific individual differences in white matter microstructure. In addition, individual differences are to a varying degree shared between tracts, indicating that general factors also affect white matter microstructure. Age-related differences in white matter microstructure were present for all tracts. Correlations among tract factors did not generally increase as a function of age, suggesting that aging is not a process with homogenous effects on white matter microstructure across the brain. These findings highlight the need for future research to examine whether relations between white matter microstructure and diverse outcomes are specific or general. PMID:22331619

Lövdén, Martin; Laukka, Erika Jonsson; Rieckmann, Anna; Kalpouzos, Grégoria; Li, Tie-Qiang; Jonsson, Tomas; Wahlund, Lars-Olof; Fratiglioni, Laura; Bäckman, Lars

2012-02-14

277

ORIGINAL RESEARCH White Matter Reorganization After Surgical Resection of Brain Tumors and Vascular Malformations  

Microsoft Academic Search

BACKGROUND AND PURPOSE: Diffusion tensor imaging (DTI) and white matter tractography (WMT) are promising techniques for estimating the course, extent, and connectivity patterns of the white matter (WM) structures in the human brain. In this study, DTI and WMT were used to evaluate WM tract reorganization after the surgical resection of brain tumors and vascular malformations. METHODS: Pre- and postoperative

M. Lazar; A. L. Alexander; P. J. Thottakara; B. Badie; A. S. Field

278

Stereotaxic white matter atlas based on diffusion tensor imaging in an ICBM template  

Microsoft Academic Search

Brain registration to a stereotaxic atlas is an effective way to report anatomic locations of interest and to perform anatomic quantification. However, existing stereotaxic atlases lack comprehensive coordinate information about white matter structures. In this paper, white matter-specific atlases in stereotaxic coordinates are introduced. As a reference template, the widely used ICBM-152 was used. The atlas contains fiber orientation maps

Susumu Mori; Kenichi Oishi; Hangyi Jiang; Li Jiang; Xin Li; Kazi Akhter; Kegang Hua; Andreia V. Faria; Asif Mahmood; Roger Woods; Arthur W. Toga; G. Bruce Pike; Pedro Rosa Neto; Alan Evans; Jiangyang Zhang; Hao Huang; Michael I. Miller; Peter van Zijl; John Mazziotta

2008-01-01

279

Microstructural Abnormalities of Short-Distance White Matter Tracts in Autism Spectrum Disorder  

ERIC Educational Resources Information Center

|Recent functional connectivity magnetic resonance imaging and diffusion tensor imaging (DTI) studies have suggested atypical functional connectivity and reduced integrity of long-distance white matter fibers in autism spectrum disorder (ASD). However, evidence for short-distance white matter fibers is still limited, despite some speculation of…

Shukla, Dinesh K.; Keehn, Brandon; Smylie, Daren M.; Muller, Ralph-Axel

2011-01-01

280

White matter growth as a mechanism of cognitive development in children  

Microsoft Academic Search

We examined the functional role of white matter growth in cognitive development. Specifically, we used hierarchical regression analyses to test the unique contributions of age versus white matter integrity in accounting for the development of information processing speed. Diffusion tensor imaging was acquired for 17 children and adolescents (age range 6–17 years), with apparent diffusion coefficient (ADC) and fractional anisotropy (FA)

Donald J. Mabbott; Michael Noseworthy; Eric Bouffet; Suzanne Laughlin; Conrad Rockel

2006-01-01

281

Adenosine in Relation to Calcium Homeostasis: Comparison Between Gray and White Matter Ischemia  

Microsoft Academic Search

In vitro studies suggest that adenosine may attenuate anoxic white matter damage as an intrinsic protective substance. The authors investigated ischemic alterations of purines in relation to tissue depolarization and extracellular calcium and amino acid concentrations in vivo using microdialysis and ion-selective electrodes in cortical gray and subcortical white matter of 10 cats during 120 minutes of global brain ischemia.

Christian Dohmen; Eiji Kumura; Gerd Rosner; Wolf-Dieter Heiss; Rudolf Graf

2001-01-01

282

Panencephalopathic type of Creutzfeldt-Jakob disease: primary involvement of the cerebral white matter  

Microsoft Academic Search

Eight necropsy cases of a “panencephalopathic” type of Creutzfeldt-Jakob disease (CJD) in the Japanese are reported. The reasons why this type should be discussed separately from other types of CJD are that there is primary involvement of the cerebral white matter as well as the cerebral cortex, and that the white matter lesion of one Japanese human brain with CJD

Toshio Mizutani; Atsushi Okumura; Masaya Oda; Hirotsugu Shiraki

1981-01-01

283

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

PubMed Central

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.

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

2012-01-01

284

Executive control function, brain activation and white matter hyperintensities in older adults  

PubMed Central

Context Older adults responding to executive control function (ECF) tasks show greater brain activation on functional MRI (fMRI). It is not clear whether greater fMRI activation indicates a strategy to compensate for underlying brain structural abnormalities while maintaining higher performance. Objective To identify the patterns of fMRI activation in relationship with ECF performance and with brain structural abnormalities. Design Cross-sectional analysis. Main variables of interest: fMRI activation, accuracy while performing an ECF task (Digit Symbol Substitution Test), volume of white matter hyperintensities and of total brain atrophy. Setting Cohort of community-dwelling older adults. Participants Data were obtained on 25 older adults (20 women, 81 years mean age). Outcome Measure Accuracy (number of correct response / total number of responses) while performing the Digit Symbol Substitution Test. Results Greater accuracy was significantly associated with greater peak fMRI activation, from ECF regions, including left middle frontal gyrus and right posterior parietal cortex. Greater WMH was associated with lower activation within accuracy-related regions. The interaction of accuracy by white matter hyperintensities volume was significant within the left posterior parietal region. Specifically, the correlation of white matter hyperintensities volume with fMRI activation varied as a function of accuracy and it was positive for greater accuracy. Associations with brain atrophy were not significant. Conclusions Recruitment of additional areas and overall greater brain activation in older adults is associated with higher performance. Posterior parietal activation may be particularly important to maintain higher accuracy in the presence of underlying brain connectivity structural abnormalities.

Venkatraman, Vijay K.; Aizenstein, Howard; Guralnik, Jack; Newman, Anne B.; Glynn, Nancy W.; Taylor, Christopher; Studenski, Stephanie; Launer, Lenore; Pahor, Marco; Williamson, Jeff; Rosano, Caterina

2009-01-01

285

Understanding white matter integrity stability for bilinguals on language status and reading performance.  

PubMed

Recent studies using diffusion tensor imaging (DTI) have described overall white matter integrity in bilinguals but have not related structural neural pathways to language functions. The current study examined white matter integrity and its relationship to reading skill in monolingual English and bilingual Chinese-English speakers. Eleven monolingual speakers (mean age 28.5 years) and 13 bilingual speakers (mean age 24.2 years; English as a second language was acquired post 5 years of age) participated. Behavioural response times and accuracy rates to name regular and exception words were recorded. Participants were then scanned using a standardized DTI protocol. Fractional anisotropy (FA) and mean diffusivity values were derived from a voxelwise statistical analysis for comparisons between participant groups. Tests for relationships between response time and FA were also conducted. Our results show minimal regions of higher FA for monolinguals when compared to bilinguals and no regions of higher FA for bilinguals when compared to monolinguals, which indicates that white matter integrity may not stabilize in bilinguals until late adulthood. We do show several regions where an increase in FA is associated with faster response times. Interestingly, the FA-response time relationship varies between groups and between word types, which may reflect an increased processing demand for retrieval of difficult words (e.g., exception words). These results provide some support for the interference control and reduced frequency hypotheses outlined by Jones et al. (Cerebr Cortex 22:892-902, 2012). The current findings advance our understanding of the underlying cortical networks associated with language status and reading skill in monolingual and bilingual adults. PMID:23097036

Cummine, Jacqueline; Boliek, Carol A

2012-10-25

286

Crosstalk between oligodendrocytes and cerebral endothelium contributes to vascular remodeling after white matter injury.  

PubMed

After stroke and brain injury, cortical gray matter recovery involves mechanisms of neurovascular matrix remodeling. In white matter, however, the mechanisms of recovery remain unclear. In this study, we demonstrate that oligodendrocytes secrete matrix metalloproteinase-9 (MMP-9), which accelerates the angiogenic response after white matter injury. In primary oligodendrocyte cultures, treatment with the proinflammatory cytokine interleukin-1? (IL-1?) induced an upregulation and secretion of MMP-9. Conditioned media from IL-1?-stimulated oligodendrocytes significantly amplified matrigel tube formation in brain endothelial cells, indicating that MMP-9 from oligodendrocytes can promote angiogenesis in vitro. Next, we asked whether similar signals and substrates operate after white matter injury in vivo. Focal white matter injury and demyelination was induced in mice via stereotactic injection of lysophosphatidylcholine into corpus callosum. Western blot analysis showed that IL-1? expression was increased in damaged white matter. Immunostaining demonstrated MMP-9 signals in myelin-associated oligodendrocytic basic protein-positive oligodendrocytes. Treatment with an IL-1?-neutralizing antibody suppressed the MMP-9 response in oligodendrocytes. Finally, we confirmed that the broad spectrum MMP inhibitor GM6001 inhibited angiogenesis around the injury area in this white matter injury model. In gray matter, a neurovascular niche promotes cortical recovery after brain injury. Our study suggests that an analogous oligovascular niche may mediate recovery in white matter. PMID:22392631

Pham, Loc-Duyen D; Hayakawa, Kazuhide; Seo, Ji Hae; Nguyen, Minh-Nguyet; Som, Angel T; Lee, Brian J; Guo, Shuzhen; Kim, Kyu-Won; Lo, Eng H; Arai, Ken

2012-03-05

287

Diffusion tensor imaging of white matter networks in individuals with current and remitted alcohol use disorders and comorbid conditions.  

PubMed

Individuals with alcohol use disorders show white matter abnormality relative to normal samples, but differences in white matter profiles have not yet been investigated as a function of abstinence. Individuals with current alcohol use disorders (AUD-C; n = 10), individuals with alcohol use disorders in remission for at least 1 year (AUD-R; n = 9), and healthy control participants (HC; n = 15) matched to alcohol groups on age and smoking status underwent MRI. Diffusion tensor imaging (DTI) data were analyzed using tract-based spatial statistics (TBSS). Compared with HC, AUD-C showed reduced axial diffusivity in bilateral frontal and temporal white matter. In AUD-R, lower fractional anisotropy relative to HC was widespread in bilateral parietal regions. A combined AUD-C and AUD-R group had decreased fractional anisotropy primarily in the fornix and thalamus. In conclusion, AUD-R manifested damage in parietal regions integral to processing of visuospatial information and self-awareness whereas AUD-C showed abnormal diffusivity in fronto-temporal regions that regulate impulsivity, attention, and memory. As a combined group, AUD individuals exhibited abnormality in subcortical areas associated with sensory processing and memory. White matter differences in individuals with AUD may be attributable to premorbid vulnerability or persisting effects of alcohol abuse, but the pattern of abnormality across groups suggests that these abnormalities may be secondary to alcohol use. PMID:22352699

Monnig, Mollie A; Caprihan, Arvind; Yeo, Ronald A; Gasparovic, Charles; Ruhl, David A; Lysne, Per; Bogenschutz, Michael P; Hutchison, Kent E; Thoma, Robert J

2012-02-20

288

Thalamo-Frontal White Matter Alterations in Chronic Schizophrenia: A Quantitative Diffusion Tractography Study  

PubMed Central

Diffusion tensor imaging (DTI) and fiber tractography are useful tools for reconstructing white matter tracts (WMT) in the brain. Previous tractography studies have sought to segment reconstructed WMT into anatomical structures using several approaches, but quantification has been limited to extracting mean values of diffusion indices. Delineating WMT in schizophrenia is of particular interest because schizophrenia has been hypothesized to be a disorder of disrupted connectivity, especially between frontal and temporal regions of the brain. In this study, we aim to differentiate diffusion properties of thalamo-frontal pathways in schizophrenia from normal controls. We present a quantitative group comparison method, which combines the strengths of both tractography-based and voxel-based studies. Our algorithm extracts white matter pathways using whole brain tractography. Functionally relevant bundles are selected and parsed from the resulting set of tracts, using an internal capsule (IC) region of interest (ROI) as “source”, and different Brodmann area (BA) ROIs as “targets”. The resulting bundles are then longitudinally parameterized so that diffusion properties can be measured and compared along the WMT. Using this processing pipeline, we were able to find altered diffusion properties in male patients with chronic schizophrenia in terms of fractional anisotropy (FA) decreases and mean diffusivity (MD) increases in precise and functionally relevant locations. These findings suggest that our method can enhance the regional and functional specificity of DTI group studies, thus improving our understanding of brain function.

Oh, Jungsu S.; Kubicki, Marek; Rosenberger, Gudrun; Bouix, Sylvain; Levitt, James; McCarley, Robert W.; Westin, Carl-Fredrik; Shenton, Martha E.

2009-01-01

289

White matter structural connectivity underlying semantic processing: evidence from brain damaged patients.  

PubMed

Widely distributed brain regions in temporal, parietal and frontal cortex have been found to be involved in semantic processing, but the anatomical connections supporting the semantic system are not well understood. In a group of 76 right-handed brain-damaged patients, we tested the relationship between the integrity of major white matter tracts and the presence of semantic deficits. The integrity of white matter tracts was measured by percentage of lesion voxels obtained in structural imaging and mean fractional anisotropy values obtained in diffusion tensor imaging. Semantic deficits were assessed by jointly considering the performance on three semantic tasks that vary in the modalities of input (visual and auditory stimuli) and output (oral naming and associative judgement). We found that the lesion volume and fractional anisotropy value of the left inferior fronto-occipital fasciculus, left anterior thalamic radiation, and left uncinate fasciculus significantly correlated with severity of impairment in all three semantic tasks. These associations remained significant even when we controlled for a wide range of potential confounding variables, including overall cognitive state, whole lesion volume, or type of brain damage. The effects of these three white matter tracts could not be explained by potential involvement of relevant grey matter, and were (relatively) specific to object semantic processing, as no correlation with performance on non-object semantic control tasks (oral repetition and number processing tasks) was observed. These results underscore the causal role of left inferior fronto-occipital fasciculus, left anterior thalamic radiation, and left uncinate fasciculus in semantic processing, providing direct evidence for (part of) the anatomical skeleton of the semantic network. PMID:23975453

Han, Zaizhu; Ma, Yujun; Gong, Gaolang; He, Yong; Caramazza, Alfonso; Bi, Yanchao

2013-08-23

290

Pathological Changes in the White Matter after Spinal Contusion Injury in the Rat  

PubMed Central

It has been shown previously that after spinal cord injury, the loss of grey matter is relatively faster than loss of white matter suggesting interventions to save white matter tracts offer better therapeutic possibilities. Loss of white matter in and around the injury site is believed to be the main underlying cause for the subsequent loss of neurological functions. In this study we used a series of techniques, including estimations of the number of axons with pathology, immunohistochemistry and mapping of distribution of pathological axons, to better understand the temporal and spatial pathological events in white matter following contusion injury to the rat spinal cord. There was an initial rapid loss of axons with no detectable further loss beyond 1 week after injury. Immunoreactivity for CNPase indicated that changes to oligodendrocytes are rapid, extending to several millimetres away from injury site and preceding much of the axonal loss, giving early prediction of the final volume of white matter that survived. It seems that in juvenile rats the myelination of axons in white matter tracts continues for some time, which has an important bearing on interpretation of our, and previous, studies. The amount of myelin debris and axon pathology progressively decreased with time but could still be observed at 10 weeks after injury, especially at more distant rostral and caudal levels from the injury site. This study provides new methods to assess injuries to spinal cord and indicates that early interventions are needed for the successful sparing of white matter tracts following injury.

Ek, C. Joakim; Habgood, Mark D.; Dennis, Ross; Dziegielewska, Katarzyna M.; Mallard, Carina; Wheaton, Benjamin; Saunders, Norman R.

2012-01-01

291

White matter lesion extension to automatic brain tissue segmentation on MRI  

Microsoft Academic Search

A fully automated brain tissue segmentation method is optimized and extended with white matter lesion segmentation. Cerebrospinal fluid (CSF), gray matter (GM) and white matter (WM) are segmented by an atlas-based k-nearest neighbor classifier on multi-modal magnetic resonance imaging data. This classifier is trained by registering brain atlases to the subject. The resulting GM segmentation is used to automatically find

Renske de Boer; Henri A. Vrooman; Fedde van der Lijn; Meike W. Vernooij; M. Arfan Ikram; Aad van der Lugt; Monique M. B. Breteler; Wiro J. Niessen

2009-01-01

292

[Age-related white matter lesions (leukoaraiosis): an update].  

PubMed

Leukoaraiosis (age-related white matter hyperintensities) is the most frequently seen lesion on brain magnetic resonance (MR) images. This lesion is a subject of much current interest, because a number of multicenter studies have revealed that it is associated with various disturbances and poor prognoses. Leukoaraiosis corresponds to various pathologies, including demyelination, apoptosis, edema, dilated perivascular spaces, axonal damage, gliosis, and infarcts. Also noted in leukoaraiosis are changes in small vessels, such as fibrohyalinosis and venous collagenosis. The main cause of leukoaraiosis is thought to be chronic ischemia; other causes include edema and breakdown of the blood-brain barrier. Major risk factors for leukoaraiosis are age and hypertension. Disturbances that are related to leukoaraiosis include stroke, dementia, cognitive impairment, gait disturbance, fall, and depression. Leukoaraiosis is also a risk factor for death. Technologies, such as automatic volumetry, tissue segmentation, diffusion tensor imaging, magnetization tensor imaging, diffusion kurtosis imaging, and ultra-high field MR imaging may provide further insights into leukoaraiosis. PMID:23832982

Miki, Yukio; Sakamoto, Shinichi

2013-07-01

293

White matter hyperintensities predict low frequency hearing in older adults.  

PubMed

Vascular disease has been proposed as a contributing factor for presbyacusis (age-related hearing loss). While this hypothesis is supported by pathological evidence of vascular decline in post-mortem human and animal studies, evidence in human subjects has been mixed with associations typically reported between a measure of vascular health and low frequency hearing in older women. Given the difficulty of characterizing the in vivo health of the cochlear artery in humans, an estimate of cerebral small vessel disease was used to test the prediction that age-related change in low frequency hearing and not high frequency hearing is related to a global decline in vascular health. We examined the extent to which these associations were specific to women and influenced by a history of high blood pressure in 72 older adults (mean age 67.12 years, SD = 8.79). Probability estimates of periventricular white matter hyperintensities (WMH) from T1- and fluid attenuated T2-weighted magnetic resonance images were significantly associated with a low frequency hearing metric across the sample, which were independent of age, but driven by women and people with a history of high blood pressure. These results support the premise that vascular declines are one mechanism underlying age-related changes in low frequency hearing. PMID:23512682

Eckert, Mark A; Kuchinsky, Stefanie E; Vaden, Kenneth I; Cute, Stephanie L; Spampinato, Maria V; Dubno, Judy R

2013-03-20

294

Sexual dimorphism in the white matter of rodents  

PubMed Central

Sexual dimorphism of astrocytes and neurons is well documented in many brain and spinal cord structures. Sexual dimorphism of oligodendrocytes (Olgs) and myelin has received less attention. We recently showed that density of Olgs in corpus callosum, fornix, and spinal cord of wild-type male rodents are more densely packed than in females; myelin proteins and myelin gene expression is likewise greater in males than in female rodents. However, glial cell proliferation and cell death were two times greater in female corpus callosum. Endogenous sex hormones, specifically lack of androgens, produce an Olg female phenotype in castrated male mouse. In vitro studies using Olgs culture also showed differences between males and females Olg survival and signaling pathways in response to sexual hormones. Sexual dimorphism of white matter tracts and glia in rodents indicates the necessity for controlling gender in experimental studies of neurodegenerative disorders. Most importantly, our studies suggest that hormones may contribute to sexual dimorphism observed in certain human diseases including multiple sclerosis.

Cerghet, Mirela; Skoff, Robert P.; Swamydas, Muthulekha; Bessert, Denise

2009-01-01

295

A Model for Diffusion in White Matter in the Brain  

PubMed Central

Diffusion of molecules in brain and other tissues is important in a wide range of biological processes and measurements ranging from the delivery of drugs to diffusion-weighted magnetic resonance imaging. Diffusion tensor imaging is a powerful noninvasive method to characterize neuronal tissue in the human brain in vivo. As a first step toward understanding the relationship between the measured macroscopic apparent diffusion tensor and underlying microscopic compartmental geometry and physical properties, we treat a white matter fascicle as an array of identical thick-walled cylindrical tubes arranged periodically in a regular lattice and immersed in an outer medium. Both square and hexagonal arrays are considered. The diffusing molecules may have different diffusion coefficients and concentrations (or densities) in different domains, namely within the tubes' inner core, membrane, myelin sheath, and within the outer medium. Analytical results are used to explore the effects of a large range of microstructural and compositional parameters on the apparent diffusion tensor and the degree of diffusion anisotropy, allowing the characterization of diffusion in normal physiological conditions as well as changes occurring in development, disease, and aging. Implications for diffusion tensor imaging and for the possible in situ estimation of microstructural parameters from diffusion-weighted MR data are discussed in the context of this modeling framework.

Sen, Pabitra N.; Basser, Peter J.

2005-01-01

296

GENETICS OF WHITE MATTER DEVELOPMENT: A DTI STUDY OF 705 TWINS AND THEIR SIBLINGS AGED 12 TO 29  

PubMed Central

White matter microstructure is under strong genetic control, yet it is largely unknown how genetic influences change from childhood into adulthood. In one of the largest brain mapping studies ever performed, we determined whether the genetic control over white matter architecture depends on age, sex, socioeconomic status (SES), and intelligence quotient (IQ). We assessed white matter integrity voxelwise using diffusion tensor imaging at high magnetic field (4-Tesla), in 705 twins and their siblings (age range 12–29; 290 M/415 F). White matter integrity was quantified using a widely accepted measure, fractional anisotropy (FA). We fitted gene-environment interaction models pointwise, to visualize brain regions where age, sex, SES and IQ modulate heritability of fiber integrity. We hypothesized that environmental factors would start to outweigh genetic factors during late childhood and adolescence. Genetic influences were greater in adolescence versus adulthood, and greater in males than in females. Socioeconomic status significantly interacted with genes that affect fiber integrity: heritability was higher in those with higher SES. In people with above-average IQ, genetic factors explained over 800% of the observed FA variability in the thalamus, genu, posterior internal capsule, and superior corona radiata. In those with below-average IQ, however, only around 40% FA variability in the same regions was attributable to genetic factors. Genes affect fiber integrity, but their effects vary with age, sex, SES and IQ. Gene-environment interactions are vital to consider in the search for specific genetic polymorphisms that affect brain integrity and connectivity.

Chiang, Ming-Chang; McMahon, Katie L.; de Zubicaray, Greig I.; Martin, Nicholas G.; Hickie, Ian; Toga, Arthur W.; Wright, Margaret J.; Thompson, Paul M.

2011-01-01

297

Genetics of white matter development: a DTI study of 705 twins and their siblings aged 12 to 29.  

PubMed

White matter microstructure is under strong genetic control, yet it is largely unknown how genetic influences change from childhood into adulthood. In one of the largest brain mapping studies ever performed, we determined whether the genetic control over white matter architecture depends on age, sex, socioeconomic status (SES), and intelligence quotient (IQ). We assessed white matter integrity voxelwise using diffusion tensor imaging at high magnetic field (4-Tesla), in 705 twins and their siblings (age range 12-29; 290 M/415 F). White matter integrity was quantified using a widely accepted measure, fractional anisotropy (FA). We fitted gene-environment interaction models pointwise, to visualize brain regions where age, sex, SES and IQ modulate heritability of fiber integrity. We hypothesized that environmental factors would start to outweigh genetic factors during late childhood and adolescence. Genetic influences were greater in adolescence versus adulthood, and greater in males than in females. Socioeconomic status significantly interacted with genes that affect fiber integrity: heritability was higher in those with higher SES. In people with above-average IQ, genetic factors explained over 80% of the observed FA variability in the thalamus, genu, posterior internal capsule, and superior corona radiata. In those with below-average IQ, however, only around 40% FA variability in the same regions was attributable to genetic factors. Genes affect fiber integrity, but their effects vary with age, sex, SES and IQ. Gene-environment interactions are vital to consider in the search for specific genetic polymorphisms that affect brain integrity and connectivity. PMID:20950689

Chiang, Ming-Chang; McMahon, Katie L; de Zubicaray, Greig I; Martin, Nicholas G; Hickie, Ian; Toga, Arthur W; Wright, Margaret J; Thompson, Paul M

2010-10-13

298

1H magnetic resonance spectroscopy of chronic cerebral white matter lesions and normal appearing white matter in multiple sclerosis  

PubMed Central

OBJECTIVES—To test the hypothesis that irrecoverable neurological deficit in multiple sclerosis is associated with axonal loss.?METHODS—1H magnetic resonance spectroscopy (MRS) was carried out in a group of patients with clinically definite multiple sclerosis (n=31).? Using this technique, the apparent concentration of NA ([NA] the sum of N-acetyl aspartate (NAA), a neuronal marker, and N-acetylaspartylglutamate has been compared in four groups of patients with multiple sclerosis classified as relapsing-remitting, secondary progressive, primary progressive, benign, and a control group.?RESULTS—In the patients with relapsing-remitting disease (n=9) there was a highly significant reduction of apparent NA (median 8.73mM, range 6.86 mM-10.74 mM, P=0.0008) from an area of high signal compared with the control group (median 11.97 mM, range 10.55mM-14.5 mM). In the patients with secondary progressive disease (n=10), there was again a highly significant reduction of apparent NA (median 7.82 mM, range 3.5 mM-10.3 mM, P=0.0003) from an area of high signal compared with the control group. In the patients with primary progressive disease (n=6) there was once again a highly significant reduction of apparent NA (median 8.83 mM, range 6.95 mM-9.89 mM, P<0.002) from an area of high signal compared with the control group. In the patients with benign disease, however, there was no significant difference in the apparent NA (median 10.5 mM, range 8.53 mM-12.8 mM, P>0.05) from an area of high signal compared with the control group. In the patients with benign disease (n=5) there was also no significant difference in the apparent NA (median 10.74 mM, range 8.58 mM-13.4 mM, P>0.3) from an area of normal appearing white matter compared with the control group. In the patients with primary progressive disease, however, there was a significant reduction of apparent NA from an area of normal appearing white matter (median 8.78 mM, range 8.7 mM-12.38 mM, P< 0.025) compared with the control group. There was a significant inverse correlation between [NA] from lesions in the patients with multiple sclerosis and disability as measured on the Kurtzke expanded disability scale score (r= -0.364, 0.05>P> 0.02).?CONCLUSION—These findings support the hypothesis that axonal loss is important in the development of disability in multiple sclerosis. They also provide evidence for axonal loss in normal appearing white matter in patients with primary progressive disease.??

Davie, C; Barker, G; Thompson, A; Tofts, P; McDonald, W; Miller, D

1997-01-01

299

Age-Related Total Gray Matter and White Matter Changes in Normal Adult Brain. Part I: Volumetric MR Imaging Analysis  

Microsoft Academic Search

BACKGROUND AND PURPOSE: A technique of segmenting total gray matter (GM) and total white matter (WM) in human brain is now available. We investigated the effects of age and sex on total fractional GM (%GM) and total fractional WM (%WM) volumes by using volumetric MR imaging in healthy adults. METHODS: Fifty-four healthy volunteers (22 men, 32 women) aged 20 -

Yulin Ge; Robert I. Grossman; James S. Babb; Marcie L. Rabin; Lois J. Mannon; Dennis L. Kolson

2002-01-01

300

Diffusion tensor imaging: serial quantitation of white matter tract maturity in premature newborns.  

PubMed

Magnetic resonance diffusion tensor imaging (DTI) enables the discrimination of white matter pathways before myelination is evident histologically or on conventional MRI. In this investigation, 14 premature neonates with no evidence of white matter abnormalities by conventional MRI were studied with DTI. A custom MR-compatible incubator with a novel high sensitivity neonatal head coil and improved acquisition and processing techniques were employed to increase image quality and spatial resolution. The technical improvements enabled tract-specific quantitative characterization of maturing white matter, including several association tracts and subcortical projection tracts not previously investigated in neonates by MR. Significant differences were identified between white matter pathways, with earlier maturing commissural tracts of the corpus callosum, and deep projection tracts of the cerebral peduncle and internal capsule exhibiting lower mean diffusivity (Dav) and higher fractional anisotropy (FA) than later maturing subcortical projection and association pathways. Maturational changes in white matter tracts included reductions in Dav and increases in FA with age due primarily to decreases in the two minor diffusion eigenvalues (lambda2 and lambda3). This work contributes to the understanding of normal white matter development in the preterm neonatal brain, an important step toward the use of DTI for the improved evaluation and treatment of white matter injury of prematurity. PMID:15219602

Partridge, Savannah C; Mukherjee, Pratik; Henry, Roland G; Miller, Steven P; Berman, Jeffrey I; Jin, Hua; Lu, Ying; Glenn, Orit A; Ferriero, Donna M; Barkovich, A James; Vigneron, Daniel B

2004-07-01

301

Frontal White Matter Volume Is Associated with Brain Enlargement and Higher Structural Connectivity in Anthropoid Primates  

PubMed Central

Previous research has indicated the importance of the frontal lobe and its ‘executive’ connections to other brain structures as crucial in explaining primate neocortical adaptations. However, a representative sample of volumetric measurements of frontal connective tissue (white matter) has not been available. In this study, we present new volumetric measurements of white and grey matter in the frontal and non-frontal neocortical lobes from 18 anthropoid species. We analyze this data in the context of existing theories of neocortex, frontal lobe and white versus grey matter hyperscaling. Results indicate that the ‘universal scaling law’ of neocortical white to grey matter applies separately for frontal and non-frontal lobes; that hyperscaling of both neocortex and frontal lobe to rest of brain is mainly due to frontal white matter; and that changes in frontal (but not non-frontal) white matter volume are associated with changes in rest of brain and basal ganglia, a group of subcortical nuclei functionally linked to ‘executive control’. Results suggest a central role for frontal white matter in explaining neocortex and frontal lobe hyperscaling, brain size variation and higher neural structural connectivity in anthropoids.

Smaers, Jeroen Bert; Schleicher, Axel; Zilles, Karl; Vinicius, Lucio

2010-01-01

302

Vulnerability of premyelinating oligodendrocytes to white-matter damage in neonatal brain injury.  

PubMed

Premature birth is a significant economic and public health burden, and its incidence is rising. Periventricular leukomalacia (PVL) is the predominant form of brain injury in premature infants and the leading cause of cerebral palsy. PVL is characterized by selective white-matter damage with prominent oligodendroglial injury. The maturation-dependent vulnerability of developing and premyelinating oligodendrocytes to excitotoxic, oxidative, and inflammatory forms of injury is a major factor in the pathogenesis of PVL. Recent studies using mouse models of PVL reveal that synapses between axons and developing oligodendrocytes are quickly and profoundly damaged in immature white matter. Axon-glia synapses are highly vulnerable to white-matter injury in the developing brain, and the loss of synapses between axons and premyelinating oligodendrocytes occurs before any cellular loss in the immature white matter. Microglial activation and astrogliosis play important roles in triggering white-matter injury. Impairment of white-matter development and function in the neonatal period contributes critically to functional and behavioral deficits. Preservation of the integrity of the white matter is likely key in the treatment of PVL and subsequent neurological consequences and disabilities. PMID:23456565

Liu, Xiao-Bo; Shen, Yan; Plane, Jennifer M; Deng, Wenbin

2013-02-28

303

Depressive symptoms in adolescents: associations with white matter volume and marijuana use  

PubMed Central

Background Depressed mood has been associated with decreased white matter and reduced hippocampal volumes. However, the relationship between brain structure and mood may be unique among adolescents who use marijuana heavily. The goal of this study was to examine the relationship between white matter and hippocampal volumes and depressive symptoms among adolescent marijuana users and controls. Methods Data were collected from marijuana users (n = 16) and demographically similar controls (n = 16) aged 16–18. Extensive exclusionary criteria included psychiatric and neurologic disorders, including major depression. Substance use, mood, and anatomical measures were collected after 28 days of monitored abstinence. Results Marijuana (MJ) users demonstrated more depressive symptoms than controls (p < .05). MJ use (? = .42, p < .005) and smaller white matter volume (? = ?.34, p < .03) each predicted higher levels of depressive symptoms on the Hamilton Depression Rating Scale. MJ use interacted with white matter volume (? = ?.55, p < .03) in predicting depression scores on the Beck Depression Inventory: among MJ users, but not controls, white matter volume was negatively associated with depressive symptoms. Conclusions Marijuana use and white matter volume were additive and interactive in predicting depressive symptoms among adolescents. Subtle neurodevelopmental white matter abnormalities may disrupt the connections between areas involved in mood regulation.

Medina, Krista Lisdahl; Nagel, Bonnie J.; Park, Ann; McQueeny, Tim; Tapert, Susan F.

2008-01-01

304

White matter alterations differ in primary lateral sclerosis and amyotrophic lateral sclerosis  

PubMed Central

Primary lateral sclerosis is a sporadic disorder characterized by slowly progressive corticospinal dysfunction. Primary lateral sclerosis differs from amyotrophic lateral sclerosis by its lack of lower motor neuron signs and long survival. Few pathological studies have been carried out on patients with primary lateral sclerosis, and the relationship between primary lateral sclerosis and amyotrophic lateral sclerosis remains uncertain. To detect in vivo structural differences between the two disorders, diffusion tensor imaging of white matter tracts was carried out in 19 patients with primary lateral sclerosis, 18 patients with amyotrophic lateral sclerosis and 19 age-matched controls. Fibre tracking was used to reconstruct the intracranial portion of the corticospinal tract and three regions of the corpus callosum: the genu, splenium and callosal fibres connecting the motor cortices. Both patient groups had reduced fractional anisotropy, a measure associated with axonal organization, and increased mean diffusivity of the reconstructed corticospinal and callosal motor fibres compared with controls, without changes in the genu or splenium. Voxelwise comparison of the whole brain white matter using tract-based spatial statistics confirmed the differences between patients and controls in the diffusion properties of the corticospinal tracts and motor fibres of the callosum. This analysis further revealed differences in the regional distribution of white matter alterations between the patient groups. In patients with amyotrophic lateral sclerosis, the greatest reduction in fractional anisotropy occurred in the distal portions of the intracranial corticospinal tract, consistent with a distal axonal degeneration. In patients with primary lateral sclerosis, the greatest loss of fractional anisotropy and mean diffusivity occurred in the subcortical white matter underlying the motor cortex, with reduced volume, suggesting tissue loss. Clinical measures of upper motor neuron dysfunction correlated with reductions in fractional anisotropy in the corticospinal tract in patients with amyotrophic lateral sclerosis and increased mean diffusivity and volume loss of the corticospinal tract in patients with primary lateral sclerosis. Changes in the diffusion properties of the motor fibres of the corpus callosum were strongly correlated with changes in corticospinal fibres in patients, but not in controls. These findings indicate that degeneration is not selective for corticospinal neurons, but affects callosal neurons within the motor cortex in motor neuron disorders.

Iwata, Nobue K.; Kwan, Justin Y.; Danielian, Laura E.; Butman, John A.; Tovar-Moll, Fernanda; Bayat, Elham

2011-01-01

305

Blood-Brain Barrier Permeability of Normal Appearing White Matter in Relapsing-Remitting Multiple Sclerosis  

PubMed Central

Background Multiple sclerosis (MS) affects the integrity of the blood-brain barrier (BBB). Contrast-enhanced T1 weighted magnetic resonance imaging (MRI) is widely used to characterize location and extent of BBB disruptions in focal MS lesions. We employed quantitative T1 measurements before and after the intravenous injection of a paramagnetic contrast agent to assess BBB permeability in the normal appearing white matter (NAWM) in patients with relapsing-remitting MS (RR-MS). Methodology/Principal Findings Fifty-nine patients (38 females) with RR-MS undergoing immunomodulatory treatment and nine healthy controls (4 females) underwent quantitative T1 measurements at 3 tesla before and after injection of a paramagnetic contrast agent (0.2 mmol/kg Gd-DTPA). Mean T1 values were calculated for NAWM in patients and total cerebral white matter in healthy subjects for the T1 measurements before and after injection of Gd-DTPA. The pre-injection baseline T1 of NAWM (945±55 [SD] ms) was prolonged in RR-MS relative to healthy controls (903±23 ms, p?=?0.028). Gd-DTPA injection shortened T1 to a similar extent in both groups. Mean T1 of NAWM was 866±47 ms in the NAWM of RR-MS patients and 824±13 ms in the white matter of healthy controls. The regional variability of T1 values expressed as the coefficient of variation (CV) was comparable between the two groups at baseline, but not after injection of the contrast agent. After intravenous Gd-DTPA injection, T1 values in NAWM were more variable in RR-MS patients (CV?=?0.198±0.046) compared to cerebral white matter of healthy controls (CV?=?0.166±0.018, p?=?0.046). Conclusions/Significance We found no evidence of a global BBB disruption within the NAWM of RR-MS patients undergoing immunomodulatory treatment. However, the increased variation of T1 values in NAWM after intravenous Gd-DTPA injection points to an increased regional inhomogeneity of BBB function in NAWM in relapsing-remitting MS.

Lund, Henrik; Krakauer, Martin; Skimminge, Arnold; Sellebjerg, Finn; Garde, Ellen; Siebner, Hartwig R.; Paulson, Olaf B.; Hesse, Dan; Hanson, Lars G.

2013-01-01

306

White-Matter Changes Correlate with Cognitive Functioning in Parkinson's Disease  

PubMed Central

Diffusion tensor imaging (DTI) findings from emerging studies of cortical white-matter integrity in Parkinson’s disease (PD) without dementia are inconclusive. When white-matter changes have been found, their relationship to cognitive functioning in PD has not been carefully investigated. To better characterize changes in tissue diffusivity and to understand their functional significance, the present study conducted DTI in 25 PD patients without dementia and 26 controls of similar ages. An automated tract-based DTI method was used. Fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD) were analyzed. Neuropsychological measures of executive functioning (working memory, verbal fluency, cognitive flexibility, inhibitory control) and visuospatial ability were then correlated with regions of interest that showed abnormal diffusivity in the PD group. We found widespread reductions in FA and increases in MD in the PD group relative to controls. These changes were predominantly related to an increase in RD. Increased AD in the PD group was limited to specific frontal tracks of the right hemisphere, possibly signifying more significant tissue changes. Motor symptom severity did not correlate with FA. However, different measures of executive functioning and visuospatial ability correlated with FA in different segments of tracts, which contain fiber pathways to cortical regions that are thought to support specific cognitive processes. The findings suggest that abnormal tissue diffusivity may be sensitive to subtle cognitive changes in PD, some of which may be prognostic of future cognitive decline.

Theilmann, Rebecca J.; Reed, Jason D.; Song, David D.; Huang, Mingxiong X.; Lee, Roland R.; Litvan, Irene; Harrington, Deborah L.

2013-01-01

307

Information-theoretic approach for automated white matter fiber tracts reconstruction.  

PubMed

Fiber tracking is the most popular technique for creating white matter connectivity maps from diffusion tensor imaging (DTI). This approach requires a seeding process which is challenging because it is not clear how and where the seeds have to be placed. On the other hand, to enhance the interpretation of fiber maps, segmentation and clustering techniques are applied to organize fibers into anatomical structures. In this paper, we propose a new approach to automatically obtain bundles of fibers grouped into anatomical regions. This method applies an information-theoretic split-and-merge algorithm that considers fractional anisotropy and fiber orientation information to automatically segment white matter into volumes of interest (VOIs) of similar FA and eigenvector orientation. For each VOI, a number of planes and seeds is automatically placed in order to create the fiber bundles. The proposed approach avoids the need for the user to define seeding or selection regions. The whole process requires less than a minute and minimal user interaction. The agreement between the automated and manual approaches has been measured for 10 tracts in a DTI brain atlas and found to be almost perfect (kappa >?0.8) and substantial (kappa >?0.6). This method has also been evaluated on real DTI data considering 5 tracts. Agreement was substantial (kappa >?0.6) in most of the cases. PMID:22467471

Prados, Ferran; Boada, Imma; Feixas, Miquel; Prats-Galino, Alberto; Blasco, Gerard; Puig, Josep; Pedraza, Salvador

2012-07-01

308

Neurocircuitry of emotion and cognition in alcoholism: contributions from white matter fiber tractography  

PubMed Central

Chronic alcoholism is characterized by impaired control over emotionally motivated actions towards alcohol use. Neuropathologically, it is associated with widespread brain structural compromise marked by gray matter shrinkage, ventricular enlargement, and white matter degradation. The extent to which cortical damage itself or cortical disconnection by white matter fiber pathway disruption contribute to deficits in emotion, cognition, and behavior can be investigated with in vivo structural neuroimaging and diffusion tensor imaging (DTI)-based quantitative fiber tracking. Tractography in alcoholism has revealed abnormalities in selective white matter fiber bundles involving limbic fiber tracts (fornix and cingulum) that connect cortico-limbic-striatal nodes of emotion and reward circuits. Studies documenting brain-behavior relationships support the role of alcoholism-related white matter fiber degradation as a substrate of clinical impairment. An understanding of the role of cortico-limbic fiber degradation in emotional dysregulation in alcoholism is now emerging.

Schulte, Tilman; Muller-Oehring, Eva M.; Pfefferbaum, Adolf; Sullivan, Edith V.

2010-01-01

309

Identification, Isolation, and Promoter-Defined Separation of Mitotic Oligodendrocyte Progenitor Cells from the Adult Human Subcortical White Matter  

Microsoft Academic Search

Previous studies have suggested the persistence of oligoden- drocyte progenitor cells in the adult mammalian subcortical white matter. To identify oligodendrocyte progenitors in the adult human subcortical white matter, we transfected dissoci- ates of capsular white matter with plasmid DNA bearing the gene for green fluorescence protein (hGFP), placed under the control of the human early promoter (P2) for the

Neeta Singh Roy; Su Wang; Catherine Harrison-Restelli; Abdellatif Benraiss; Richard A. R. Fraser

1999-01-01

310

Altered Glutamatergic Metabolism Associated with Punctate White Matter Lesions in Preterm Infants  

PubMed Central

Preterm infants (?10% of all births) are at high-risk for long-term neurodevelopmental disabilities, most often resulting from white matter injury sustained during the neonatal period. Glutamate excitotoxicity is hypothesized to be a key mechanism in the pathogenesis of white matter injury; however, there has been no in vivo demonstration of glutamate excitotoxicity in preterm infants. Using magnetic resonance spectroscopy (MRS), we tested the hypothesis that glutamate and glutamine, i.e., markers of glutamatergic metabolism, are altered in association with punctate white matter lesions and “diffuse excessive high signal intensity” (DEHSI), the predominant patterns of preterm white matter injury. We reviewed all clinically-indicated MRS studies conducted on preterm infants at a single institution during a six-year period and determined the absolute concentration of glutamate, glutamine, and four other key metabolites in the parietal white matter in 108 of those infants after two investigators independently evaluated the studies for punctate white matter lesions and DEHSI. Punctate white matter lesions were associated with a 29% increase in glutamine concentration (p?=?0.002). In contrast, there were no differences in glutamatergic metabolism in association with DEHSI. Severe DEHSI, however, was associated with increased lactate concentration (p?=?0.001), a marker of tissue acidosis. Findings from this study support glutamate excitotoxicity in the pathogenesis of punctate white matter lesions, but not necessarily in DEHSI, and suggest that MRS provides a useful biomarker for determining the pathogenesis of white matter injury in preterm infants during a period when neuroprotective agents may be especially effective.

Wisnowski, Jessica L.; Bluml, Stefan; Paquette, Lisa; Zelinski, Elizabeth; Nelson, Marvin D.; Painter, Michael J.; Damasio, Hanna; Gilles, Floyd; Panigrahy, Ashok

2013-01-01

311

White matter abnormalities in Parkinson's disease patients with glucocerebrosidase gene mutations.  

PubMed

Glucocerebrosidase gene mutations represent a genetic risk factor for the development of Parkinson's disease. This study investigated brain alterations in Parkinson's disease patients carrying heterozygous glucocerebrosidase gene mutations using structural and diffusion tensor magnetic resonance imaging. Among 360 Parkinson's disease patients screened for glucocerebrosidase gene mutations, 19 heterozygous mutation carriers (5.3%) were identified. Of these, 15 patients underwent a neuropsychological evaluation and a magnetic resonance imaging scan. Sixteen age- and sex-matched healthy controls and 14 idiopathic Parkinson's disease patients without glucocerebrosidase gene mutations were also studied. Tract-based spatial statistics was used to perform a white matter voxel-wise analysis of diffusion tensor magnetic resonance imaging metrics. Mean fractional anisotropy values were obtained from white matter tracts of interest. Voxel-based morphometry was used to assess gray-matter atrophy. Cognitive deficits were found in 9 mutation carrier patients (60%). Compared with controls, Parkinson's disease patients carrying glucocerebrosidase gene mutations showed decreased fractional anisotropy in the olfactory tracts, corpus callosum, and anterior limb of the internal capsule bilaterally, as well as in the right anterior external capsule, and left cingulum, parahippocampal tract, parietal portion of the superior longitudinal fasciculus, and occipital white matter. Mutation carrier patients also had decreased fractional anisotropy of the majority of white matter tracts compared with Parkinson's disease patients with no mutations. No white matter abnormalities were found in Parkinson's disease patients without glucocerebrosidase gene mutations. No gray matter difference was found between patients and controls. In Parkinson's disease patients, verbal fluency scores correlated with white matter abnormalities. Parkinson's disease patients carrying glucocerebrosidase gene mutations experience a distributed pattern of white matter abnormalities involving the interhemispheric, frontal corticocortical, and parahippocampal tracts. White matter pathology in these patients may have an impact on the clinical manifestations of the disease, including cognitive impairment. PMID:23418083

Agosta, Federica; Kostic, Vladimir S; Davidovic, Kristina; Kresojevi?, Nikola; Sarro, Lidia; Svetel, Marina; Stankovi?, Iva; Comi, Giancarlo; Klein, Christine; Filippi, Massimo

2013-02-15

312

Age-related changes in prefrontal white matter volume across adolescence  

PubMed Central

Past research has suggested that white matter volume increases from childhood to adulthood; however, during adolescence, there is somewhat limited data to support this finding. In the present study, 65 typically developing adolescents underwent structural magnetic resonance imaging. Using magnetic resonance imaging, prefrontal white matter volumes were examined in relation to adolescent age and sex. Surprisingly, results suggested that prefrontal white matter volume decreased during late adolescence, particularly among the female sex. These findings are inconsistent with past research and suggest that perhaps some developmental processes in late adolescence are not yet fully explained. Possible methodological contributions and implications for the current findings are discussed

Nagel, Bonnie J.; Medina, Krista Lisdahl; Yoshii, June; Schweinsburg, Alecia D.; Moadab, Ida; Tapert, Susan F.

2008-01-01

313

Fractional anisotropy in white matter tracts of very-low-birth-weight infants  

Microsoft Academic Search

Background  Advances in neonatal intensive care have not yet reduced the high incidence of neurodevelopmental disability among very-low-birth-weight\\u000a (VLBW) infants. As neurological deficits are related to white-matter injury, early detection is important. Diffusion tensor\\u000a imaging (DTI) could be an excellent tool for assessment of white-matter injury. \\u000a \\u000a \\u000a \\u000a Objective  To provide DTI fractional anisotropy (FA) reference values for white-matter tracts of VLBW infants for

Jeroen Dudink; Maarten Lequin; Carola van Pul; Jan Buijs; Nikk Conneman; Johannes van Goudoever; Paul Govaert

2007-01-01

314

Genetics of age-related white matter lesions from linkage to genome wide association studies  

PubMed Central

White matter lesions are a frequent phenomenon in the elderly and contribute to the development of disability. The mechanisms underlying these brain lesions are still not fully understood with age and hypertension being the most well established risk factors. The heritability of white matter lesions is consistently high in different populations. Candidate gene studies strongly support the role of genes involved in the renin–angiotensin system, as well as Notch3 signaling. The recent genome wide association study by the CHARGE consortium identified a novel locus on chromosome 17q25 harboring several genes such as TRIM65 and TRIM47 which pinpoint to possible novel mechanisms leading to white matter lesions.

Freudenberger, Paul; Schmidt, Reinhold; Schmidt, Helena

2012-01-01

315

Prefrontal white matter volume is disproportionately larger in humans than in other primates.  

PubMed

Determining how the human brain differs from nonhuman primate brains is central to understanding human behavioral evolution. There is currently dispute over whether the prefrontal cortex, which mediates evolutionarily interesting behaviors, has increased disproportionately. Using magnetic resonance imaging brain scans from 11 primate species, we measured gray, white and total volumes for both prefrontal and the entire cerebrum on each specimen (n = 46). In relative terms, prefrontal white matter shows the largest difference between human and nonhuman, whereas gray matter shows no significant difference. This suggests that connectional elaboration (as gauged by white matter volume) played a key role in human brain evolution. PMID:15665874

Schoenemann, P Thomas; Sheehan, Michael J; Glotzer, L Daniel

2005-01-23

316

Unsupervised White Matter Fiber Clustering and Tract Probability Map Generation: Applications of a Gaussian Process framework for white matter fibers  

PubMed Central

With the increasing importance of fiber tracking in diffusion tensor images for clinical needs, there has been a growing demand for an objective mathematical framework to perform quantitative analysis of white matter fiber bundles incorporating their underlying physical significance. This paper presents such a novel mathematical framework that facilitates mathematical operations between tracts using an inner product based on Gaussian processes, between fibers which span a metric space. This metric facilitates combination of fiber tracts, rendering operations like tract membership to a bundle or bundle similarity simple. Based on this framework, we have designed an automated unsupervised atlas-based clustering method that does not require manual initialization nor an a priori knowledge of the number of clusters. Quantitative analysis can now be performed on the clustered tract volumes across subjects thereby avoiding the need for point parametrization of these fibers, or the use of medial or envelope representations as in previous work. Experiments on synthetic data demonstrate the mathematical operations. Subsequently, the applicability of the unsupervised clustering framework has been demonstrated on a 21 subject dataset.

Wassermann, D.; Bloy, L.; Kanterakis, E.; Verma, R.; Deriche, R.

2010-01-01

317

Loss of white matter microstructural integrity is associated with adverse neurological outcome in Tuberous Sclerosis Complex  

PubMed Central

Rationale and Objectives Tuberous Sclerosis Complex (TSC) is a genetic neurocutaneous syndrome in which cognitive and social-behavioral outcomes for patients vary widely in an unpredictable manner. The cause of adverse neurological outcome remains unclear. We investigated the hypothesis that disordered white matter and abnormal neural connectivity are associated with adverse neurological outcome. Materials and Methods Structural and diffusion magnetic resonance imaging was carried out in 40 subjects with TSC (age range 0.5 – 25 years, mean age 7.2 and median age 5 years), 12 of whom had autism spectrum disorders (ASD), and in 29 age-matched controls. Tractography of the corpus callosum was used to define a 3-dimensional volume of interest. Regional averages of four diffusion scalar parameters of the callosal projections were calculated for each subject. These were the average fractional anisotropy (AFA) and average mean, radial and axial diffusivity (AMD, ARD, AAD). Results Subjects with TSC had significantly lower AFA and higher AMD, ARD and AAD values compared to controls. Subjects with TSC and ASD had significantly lower AFA values compared to those without ASD, and compared to controls. TSC subjects without ASD had similar AFA values compared to controls. Conclusion Diffusion tensor scalar parameters provided measures of properties of the three-dimensional callosal projections. In TSC, changes in these parameters may reflect microstructural changes in myelination, axonal integrity, or extracellular environment. Alterations in white matter microstructural properties were associated with TSC and larger changes were associated with TSC and ASD, thus establishing a relationship between altered white matter microstructural integrity and brain function.

Peters, Jurriaan M.; Sahin, Mustafa; Vogel-Farley, Vanessa K.; Jeste, Shafali S.; Nelson, Charles A.; Gregas, Matthew C.; Prabhu, Sanjay P.; Scherrer, Benoit; Warfield, Simon K.

2012-01-01

318

Assessing White Matter Integrity as a Function of Abstinence Duration in Former Cocaine-Dependent Individuals  

PubMed Central

Current cocaine-dependent users show reductions in white matter (WM) integrity, especially in cortical regions associated with cognitive control that have been associated with inhibitory dysfunction. A key question is whether these white matter differences are present following abstinence from drug use. To address this, WM integrity was examined using diffusion tensor imaging (DTI) obtained on 43 cocaine abstinent patients (abstinence duration ranged between five days and 102 weeks) and 43 non-using controls. Additionally, a cross-sectional comparison separated the patients into three groups (short-term, mid-term and long-term) based upon duration of cocaine abstinence. The 43 cocaine abstinent patients showed lower fractional anisotropy (FA) in the left anterior callosal fibers, left genu of the corpus callosum, right superior longitudinal fasciculus, right callosal fibers and the superior corona radiata bilaterally when compared against non-using controls. Higher FA in the cocaine abstinent patients was observed in the splenium of the corpus callosum and right superior longitudinal fasciculus. Differences between the cocaine abstinent groups were observed bilaterally in the inferior longitudinal fasciculus, right anterior thalamic radiation, right ventral posterolateral nucleus of the thalamus, left superior corona radiata, superior longitudinal fasciculus bilaterally, right cingulum and the WM of the right precentral gyrus. The results identified WM differences between cocaine abstinent patients and controls as well as distinct differences between abstinent subgroups. The findings suggest that specific white matter differences persist throughout abstinence while other, spatially distinct, differences discriminate as a function of abstinence duration. These differences may, therefore, represent brain changes that mark recovery from addiction.

Bell, Ryan P.; Foxe, John J.; Nierenberg, Jay; Hoptman, Matthew J.; Garavan, Hugh

2010-01-01

319

Lower diffusion in white matter of children with prenatal methamphetamine exposure  

PubMed Central

Background: Methamphetamine use is a common problem among women of childbearing age, leading to an increasing number of children with prenatal methamphetamine exposure. Whether microstructural brain changes associated with prenatal methamphetamine exposure can be detected with diffusion tensor imaging (DTI) is unknown. Method: Twelve-direction DTI was performed in 29 methamphetamine-exposed and 37 unexposed children ages 3–4 years on a 3-T MRI scanner. Fractional anisotropy (FA) and apparent diffusion coefficient (ADC) were determined in the corpus callosum (genu and splenium) and bilaterally in the frontal and parietal white matter (WM), basal ganglia (caudate, putamen, globus pallidus), and thalamus. Results: Children with prenatal methamphetamine exposure had lower ADC in the frontal (right: ?2.1%, p = 0.04; left: ?2.0%, p = 0.09) and parietal WM (right: ?3.9%, p = 0.002; left: ?3.3%, p = 0.02) compared to unexposed children. The methamphetamine-exposed children also showed a trend for higher FA in the left frontal WM (+4.9%, p = 0.06) compared to the unexposed children. Conclusion: Since less myelination and higher dendritic or spine density have been reported in animals exposed to methamphetamine, lower diffusion in our children may reflect more compact axons or greater dendritic or spine density associated with prenatal methamphetamine exposure. These findings suggest alterations in white matter maturation in these children exposed to methamphetamine in utero. GLOSSARY ADC = apparent diffusion coefficient; ANOVA = analysis of variance; ASI = Addiction Severity Index; CES-D = Center for Epidemiologic Studies–Depression scale; DSM-IV = Diagnostic and Statistical Manual of Mental Disorders, 4th edition; DTI = diffusion tensor imaging; EPI = echoplanar imaging; FA = fractional anisotropy; ISP = Index of Social Position; NART-R = National Adult Reading Test; ROI = region of interest; SASSI = Substance Abuse Subtle Screening Inventory; TE = echo time; TI = inversion time; TR = repetition time; VIQ = verbal intelligence; WM = white matter.

Cloak, C C.; Ernst, T; Fujii, L; Hedemark, B; Chang, L

2009-01-01

320

Delay discounting behavior and white matter microstructure abnormalities in youth with a family history of alcoholism  

PubMed Central

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.

Herting, Megan M.; Schwartz, Daniel; Mitchell, Suzanne H.; Nagel, Bonnie J.

2011-01-01

321

Cerebral white matter integrity and executive function in adult survivors of childhood medulloblastoma  

PubMed Central

Survivors of pediatric medulloblastoma are at risk for neurocognitive dysfunction. Reduced white matter integrity has been correlated with lower intelligence in child survivors, yet associations between specific cognitive processes and white matter have not been examined in long-term adult survivors. Twenty adult survivors of medulloblastoma were randomly recruited from a larger institutional cohort of adult survivors of childhood cancer. Survivors underwent comprehensive neurocognitive evaluations and MRI. Data on brain volume and cortical thickness and diffusion tensor imaging were acquired, including measures of fractional anisotropy, apparent diffusion coefficient, and axial and radial diffusivity. Observed neurocognitive scores were compared with population norms and correlated to MRI indices. Survivors were, on average, 29 years of age and 18 years postdiagnosis. Mean full-scale intelligence quotient was nearly 1 SD below the normative mean (86.3 vs 100, P = .004). Seventy-five percent of survivors were impaired on at least one measure of executive function. Radial diffusivity in the frontal lobe of both hemispheres was correlated with shifting attention (left: rs = ?0.67, P = .001; right: rs = ?0.64, P = .002) and cognitive flexibility (left: rs = ?0.56, P = .01; right: rs = ?0.54, P = .01). Volume and cortical thickness were not correlated with neurocognitive function. Neurocognitive impairment was common and involved many domains. Reduced white matter integrity in multiple brain regions correlated with poorer performance on tasks of executive function. Future research integrating diffusion tensor imaging should be a priority to more rigorously evaluate long-term consequences of cancer treatment and to inform cognitive intervention trials in this high-risk population.

Brinkman, Tara M.; Reddick, Wilburn E.; Luxton, Joshua; Glass, John O.; Sabin, Noah D.; Srivastava, Deo Kumar; Robison, Leslie L.; Hudson, Melissa M.; Krull, Kevin R.

2012-01-01

322

Genetics of microstructure of cerebral white matter using diffusion tensor imaging  

PubMed Central

We analyzed the degree of genetic control over intersubject variability in the microstructure of cerebral white matter (WM) using diffusion tensor imaging (DTI). We performed heritability, genetic correlation and quantitative trait loci (QTL) analyses for the whole-brain and 10 major cerebral WM tracts. Average measurements for fractional anisotropy (FA), radial (L?) and axial (L||) diffusivities served as quantitative traits. These analyses were done in 467 healthy individuals (182 males/285 females; average age 47.9±13.5 years; age range:19–85 years), recruited from randomly-ascertained pedigrees of extended families. Significant heritability was observed for FA (h2=.52±.11;p=10?7) and L?(h2=.37±.14; p=0.001), while L|| measurements were not significantly heritable (h2=.09±.12; p=.20). Genetic correlation analysis indicated that the FA and L? shared 46% of the genetic variance. Tract-wise analysis revealed a regionally diverse pattern of genetic control, which was unrelated to ontogenic factors, such as tract-wise age-of-peak FA values and rates of age-related change in FA. QTL analysis indicated linkages for whole-brain average FA (LOD=2.36) at the marker D15S816on chromosome 15q25, and for L?(LOD=2.24) near the marker D3S1754 on the chromosome 3q27. These sites have been reported to have significant co-inheritance with two psychiatric disorders (major depression and obsessive-compulsive disorder) in which patients show characteristic alterations in cerebral WM. Our findings suggest that the microstructure of cerebral white matter is under a strong genetic control and further studies in healthy as well as patients with brain-related illnesses are imperative to identify the genes that may influence cerebral white matter.

Kochunov, P.; Glahn, D.C.; Lancaster, J.L.; Winkler, A.M.; Smith, S.; Thompson, P.M.; Almasy, L.; Duggirala, R.; Fox, P.T.; Blangero, J.

2010-01-01

323

Genetics of microstructure of cerebral white matter using diffusion tensor imaging.  

PubMed

We analyzed the degree of genetic control over intersubject variability in the microstructure of cerebral white matter (WM) using diffusion tensor imaging (DTI). We performed heritability, genetic correlation and quantitative trait loci (QTL) analyses for the whole-brain and 10 major cerebral WM tracts. Average measurements for fractional anisotropy (FA), radial (L( perpendicular)) and axial (L( vertical line)) diffusivities served as quantitative traits. These analyses were done in 467 healthy individuals (182 males/285 females; average age 47.9+/-13.5 years; age range: 19-85 years), recruited from randomly-ascertained pedigrees of extended families. Significant heritability was observed for FA (h(2)=0.52+/-0.11; p=10(-7)) and L( perpendicular) (h(2)=0.37+/-0.14; p=0.001), while L( vertical line) measurements were not significantly heritable (h(2)=0.09+/-0.12; p=0.20). Genetic correlation analysis indicated that the FA and L( perpendicular) shared 46% of the genetic variance. Tract-wise analysis revealed a regionally diverse pattern of genetic control, which was unrelated to ontogenic factors, such as tract-wise age-of-peak FA values and rates of age-related change in FA. QTL analysis indicated linkages for whole-brain average FA (LOD=2.36) at the marker D15S816 on chromosome 15q25, and for L( perpendicular) (LOD=2.24) near the marker D3S1754 on the chromosome 3q27. These sites have been reported to have significant co-inheritance with two psychiatric disorders (major depression and obsessive-compulsive disorder) in which patients show characteristic alterations in cerebral WM. Our findings suggest that the microstructure of cerebral white matter is under a strong genetic control and further studies in healthy as well as patients with brain-related illnesses are imperative to identify the genes that may influence cerebral white matter. PMID:20117221

Kochunov, P; Glahn, D C; Lancaster, J L; Winkler, A M; Smith, S; Thompson, P M; Almasy, L; Duggirala, R; Fox, P T; Blangero, J

2010-01-29

324

The brain in myotonic dystrophy 1 and 2: evidence for a predominant white matter disease.  

PubMed

Myotonic dystrophy types 1 and 2 are progressive multisystemic disorders with potential brain involvement. We compared 22 myotonic dystrophy type 1 and 22 myotonic dystrophy type 2 clinically and neuropsychologically well-characterized patients and a corresponding healthy control group using structural brain magnetic resonance imaging at 3 T (T(1)/T(2)/diffusion-weighted). Voxel-based morphometry and diffusion tensor imaging with tract-based spatial statistics were applied for voxel-wise analysis of cerebral grey and white matter affection (P(corrected) < 0.05). We further examined the association of structural brain changes with clinical and neuropsychological data. White matter lesions rated visually were more prevalent and severe in myotonic dystrophy type 1 compared with controls, with frontal white matter most prominently affected in both disorders, and temporal lesions restricted to myotonic dystrophy type 1. Voxel-based morphometry analyses demonstrated extensive white matter involvement in all cerebral lobes, brainstem and corpus callosum in myotonic dystrophy types 1 and 2, while grey matter decrease (cortical areas, thalamus, putamen) was restricted to myotonic dystrophy type 1. Accordingly, we found more prominent white matter affection in myotonic dystrophy type 1 than myotonic dystrophy type 2 by diffusion tensor imaging. Association fibres throughout the whole brain, limbic system fibre tracts, the callosal body and projection fibres (e.g. internal/external capsules) were affected in myotonic dystrophy types 1 and 2. Central motor pathways were exclusively impaired in myotonic dystrophy type 1. We found mild executive and attentional deficits in our patients when neuropsychological tests were corrected for manual motor dysfunctioning. Regression analyses revealed associations of white matter affection with several clinical parameters in both disease entities, but not with neuropsychological performance. We showed that depressed mood and fatigue were more prominent in patients with myotonic dystrophy type 1 with less white matter affection (early disease stages), contrary to patients with myotonic dystrophy type 2. Thus, depression in myotonic dystrophies might be a reactive adjustment disorder rather than a direct consequence of structural brain damage. Associations of white matter affection with age/disease duration as well as patterns of cerebral water diffusion parameters pointed towards an ongoing process of myelin destruction and/or axonal loss in our cross-sectional study design. Our data suggest that both myotonic dystrophy types 1 and 2 are serious white matter diseases with prominent callosal body and limbic system affection. White matter changes dominated the extent of grey matter changes, which might argue against Wallerian degeneration as the major cause of white matter affection in myotonic dystrophies. PMID:22131273

Minnerop, Martina; Weber, Bernd; Schoene-Bake, Jan-Christoph; Roeske, Sandra; Mirbach, Sandra; Anspach, Christian; Schneider-Gold, Christiane; Betz, Regina C; Helmstaedter, Christoph; Tittgemeyer, Marc; Klockgether, Thomas; Kornblum, Cornelia

2011-11-29

325

Multiple Sclerosis Normal-Appearing White Matter: Pathology-Imaging Correlations  

PubMed Central

Objective To determine the pathologic basis of subtle abnormalities in magnetization transfer ratio (MTR) and diffusion tensor imaging (DTI) parameters observed in normal-appearing white matter (NAWM) in multiple sclerosis (MS) brains. Methods Brain tissues were obtained through a rapid post-mortem protocol that included in situ MRI. Four types of MRI-defined regions of interest (ROIs) were analyzed: (1) Regions that were abnormal on all images (“T2T1MTR lesions”); (2) NAWM regions with slightly-abnormal MTR located close to white matter lesions (“sa-WM Close”); (3) NAWM regions with slightly-abnormal MTR located far from lesions (“sa-WM Far”); and (4) NAWM regions with normal MTR (“NAWM”). Immunohistochemical analysis for each ROI comprised immunostaining for myelin, axonal markers, activated microglia/macrophages, astrocytes, plasma proteins and blood vessels. Results Forty-eight ROIs from four secondary progressive MS brains were analyzed. Sa-WM Close ROIs were associated with significantly more axonal swellings. There were more enlarged MHCII(+) microglia and macrophages detected in sa-WM Far, sa-WM Close, and T2T1MTR lesions than in NAWM. Across all ROIs, MTR and DTI measures were moderately correlated with myelin density, axonal area and axonal counts. Excluding T2T1MTR lesions from analysis revealed that MTR and DTI measures in non-lesional WM were correlated with activated microglia, but not with axonal or myelin integrity. Interpretation The pathologic substrates for MRI abnormalities in NAWM vary based on distance from focal WM lesions. Close to WM lesions, axonal pathology and microglial activation may explain subtle MRI changes. Distant from lesions, microglial activation associated with proximity to cortical lesions might underlie MRI abnormalities.

Moll, Natalia M.; Rietsch, Anna M.; Thomas, Smitha; Ransohoff, Amy J.; Lee, Jar-Chi; Fox, Robert; Chang, Ansi; Ransohoff, Richard M.; Fisher, Elizabeth

2011-01-01

326

The human cerebral cortex is neither one nor many: neuronal distribution reveals two quantitatively different zones in the gray matter, three in the white matter, and explains local variations in cortical folding  

PubMed Central

The human prefrontal cortex has been considered different in several aspects and relatively enlarged compared to the rest of the cortical areas. Here we determine whether the white and gray matter of the prefrontal portion of the human cerebral cortex have similar or different cellular compositions relative to the rest of the cortical regions by applying the Isotropic Fractionator to analyze the distribution of neurons along the entire anteroposterior axis of the cortex, and its relationship with the degree of gyrification, number of neurons under the cortical surface, and other parameters. The prefrontal region shares with the remainder of the cerebral cortex (except for occipital cortex) the same relationship between cortical volume and number of neurons. In contrast, both occipital and prefrontal areas vary from other cortical areas in their connectivity through the white matter, with a systematic reduction of cortical connectivity through the white matter and an increase of the mean axon caliber along the anteroposterior axis. These two parameters explain local differences in the distribution of neurons underneath the cortical surface. We also show that local variations in cortical folding are neither a function of local numbers of neurons nor of cortical thickness, but correlate with properties of the white matter, and are best explained by the folding of the white matter surface. Our results suggest that the human cerebral cortex is divided in two zones (occipital and non-occipital) that differ in how neurons are distributed across their gray matter volume and in three zones (prefrontal, occipital, and non-occipital) that differ in how neurons are connected through the white matter. Thus, the human prefrontal cortex has the largest fraction of neuronal connectivity through the white matter and the smallest average axonal caliber in the white matter within the cortex, although its neuronal composition fits the pattern found for other, non-occipital areas.

Ribeiro, Pedro F. M.; Ventura-Antunes, Lissa; Gabi, Mariana; Mota, Bruno; Grinberg, Lea T.; Farfel, Jose M.; Ferretti-Rebustini, Renata E. L.; Leite, Renata E. P.; Filho, Wilson J.; Herculano-Houzel, Suzana

2013-01-01

327

Effects of DTI spatial normalization on white matter tract reconstructions  

PubMed Central

Major white matter (WM) pathways in the brain can be reconstructed in vivo using tractography on diffusion tensor imaging (DTI) data. Performing tractography using the native DTI data is often considered to produce more faithful results than performing it using the spatially normalized DTI obtained using highly non-linear transformations. However, tractography in the normalized DTI is playing an increasingly important role in population analyses of the WM. In particular, the emerging tract specific analyses (TSA) can benefit from tractography in the normalized DTI for statistical parametric mapping in specific WM pathways. It is well known that the preservation of tensor orientations at the individual voxel level is enforced in tensor based registrations. However small reorientation errors at individual voxel level can accumulate and could potentially affect the tractography results adversely. To our knowledge, there has been no study investigating the effects of normalization on consistency of tractography that demands non-local preservation of tensor orientations which is not explicitly enforced in typical DTI spatial normalization routines. This study aims to evaluate and compare tract reconstructions obtained using normalized DTI against those obtained using native DTI. Although tractography results have been used to measure and influence the quality of spatial normalization, the presented study addresses a distinct question: whether non-linear spatial normalization preserves even long-range anatomical connections obtained using tractography for accurate reconstructions of pathways. Our results demonstrate that spatial normalization of DTI data does preserve tract reconstructions of major WM pathways and does not alter the variance (individual differences) of their macro and microstructural properties. This suggests one can extract quantitative and shape properties efficiently from the tractography data in the normalized DTI for performing population statistics on major WM pathways.

Adluru, Nagesh; Zhang, Hui; Tromp, Do P. M.; Alexander, Andrew L.

2013-01-01

328

Neurons in the White Matter of the Adult Human Neocortex  

PubMed Central

The white matter (WM) of the adult human neocortex contains the so-called “interstitial neurons”. They are most numerous in the superficial WM underlying the cortical gyri, and decrease in density toward the deep WM. They are morphologically heterogeneous. A subgroup of interstitial neurons display pyramidal-cell like morphologies, characterized by a polarized dendritic tree with a dominant apical dendrite, and covered with a variable number of dendritic spines. In addition, a large contingent of interstitial neurons can be classified as interneurons based on their neurochemical profile as well as on morphological criteria. WM- interneurons have multipolar or bipolar shapes and express GABA and a variety of other neuronal markers, such as calbindin and calretinin, the extracellular matrix protein reelin, or neuropeptide Y, somatostatin, and nitric oxide synthase. The heterogeneity of interstitial neurons may be relevant for the pathogenesis of Alzheimer disease and schizophrenia. Interstitial neurons are most prominent in human brain, and only rudimentary in the brain of non-primate mammals. These evolutionary differences have precluded adequate experimental work on this cell population, which is usually considered as a relict of the subplate, a transient compartment proper of development and without a known function in the adult brain. The primate-specific prominence of the subplate in late fetal stages points to an important role in the establishment of interstitial neurons. Neurons in the adult WM may be actively involved in coordinating inter-areal connectivity and regulation of blood flow. Further studies in primates will be needed to elucidate the developmental history, adult components and activities of this large neuronal system.

Suarez-Sola, M. Luisa; Gonzalez-Delgado, Francisco J.; Pueyo-Morlans, Mercedes; Medina-Bolivar, O. Carolina; Hernandez-Acosta, N. Carolina; Gonzalez-Gomez, Miriam; Meyer, Gundela

2009-01-01

329

Discrimination and psychological distress: does Whiteness matter for Arab Americans?  

PubMed

The white racial category in the U.S. encompasses persons who have Arab ancestry. Arab Americans, however, have always occupied a precarious position in relationship to Whiteness. This study examined differences in reporting racial/ethnic discrimination among Arab Americans. It also investigated whether and how the association between discrimination and psychological distress varies by characteristics that capture an Arab American's proximity to/distance from Whiteness. We used data from the Detroit Arab American Study (2003; n = 1016), which includes measures of discrimination and the Kessler-10 scale of psychological distress. A series of logistic regression models were specified to test the discrimination-psychological distress association, stratified by five measures that capture Whiteness--subjective racial identification, religion, skin color, ethnic centrality, and residence in the ethnic enclave. Discrimination was more frequently reported by Muslim Arab Americans, those who racially identify as non-white, and who live in the ethnic enclave. Conversely, the association between discrimination and psychological distress was stronger for Christian Arab Americans, those who racially identify as white, who have dark skin color, and who live outside the ethnic enclave. Even though Arab Americans who occupy an identity location close to Whiteness are less subjected to discrimination, they are more negatively affected by it. The findings illuminate the complex pathways through which discrimination associates with psychological distress among 'white' immigrants. Further research on discrimination and health among Arab Americans can help unpack the white racial category and deconstruct Whiteness. PMID:22901668

Abdulrahim, Sawsan; James, Sherman A; Yamout, Rouham; Baker, Wayne

2012-08-08

330

Short-term learning induces white matter plasticity in the fornix.  

PubMed

Magnetic resonance imaging (MRI) has greatly extended the exploration of neuroplasticity in behaving animals and humans. Imaging studies recently uncovered structural changes that occur in gray and white matter, mainly after long-term training. A recent diffusion tensor imaging (DTI) study showed that training in a car racing game for 2 h induces changes in the hippocampus and parahippocampal gyri. However, the effect of short-term training on the white matter microstructure is unknown. Here we investigated the influence of short learning tasks on structural plasticity in the white matter, and specifically in the fornix, in humans and rats. Human subjects performed a 2 h spatial learning task, and rats underwent training for 1 d in a Morris water maze. Between tasks, subjects were scanned with DTI, a diffusion MRI framework sensitive to tissue microstructure. Using tract-based spatial statistics, we found changes in diffusivity indices in both humans and rats. In both species, changes in diffusion in the fornix were correlated with diffusion changes in the hippocampus, as well as with behavioral measures of improvement in the learning tasks. These results, which provide the first indication of short-term white matter plasticity in the human brain, suggest that the adult brain white matter preserves dynamic characteristics and can be modified by short-term learning experiences. The extent of change in white matter was correlated with their extent in gray matter, suggesting that all components of the neural network are capable of rapid remodeling in response to cognitive experiences. PMID:23904619

Hofstetter, Shir; Tavor, Ido; Tzur Moryosef, Shimrit; Assaf, Yaniv

2013-07-31

331

White Matter Integrity and Reaction Time Intraindividual Variability in Healthy Aging and Early-Stage Alzheimer Disease  

PubMed Central

Aging and early-stage Alzheimer disease (AD) have been shown to be associated with increased RT intraindividual variability (IIV, as reflected by the coefficient of variation) and an exaggeration of the slow tail of the RT distribution in attentional control tasks, based on ex-Gaussian analyses. The current study examined associations between white matter volume, IIV, and ex-Gaussian RT distribution parameters in cognitively normal aging and early-stage AD. Three RT attention tasks (Stroop, Simon, and a consonant-vowel odd-even switching task) in conjunction with MRI-based measures of cerebral and regional white matter volume were obtained in 133 cognitively normal and 33 early-stage AD individuals. Larger volumes were associated with less IIV and less slowing in the tail of the RT distribution, and larger cerebral and inferior parietal white matter volumes were associated with faster modal reaction time. Collectively, these results support a role of white matter integrity in IIV and distributional skewing, and are consistent with the hypothesis that IIV and RT distributional skewing are sensitive to breakdowns in executive control processes in normal and pathological aging.

Jackson, Jonathan D.; Balota, David A.; Duchek, Janet M.; Head, Denise

2011-01-01

332

Differences in supratentorial white matter diffusion after radiotherapy - new biomarker of normal brain tissue damage?  

PubMed

Abstract Introduction. Therapy-induced injury to normal brain tissue is a concern in the treatment of all types of brain tumours. The purpose of this study was to investigate if magnetic resonance diffusion tensor imaging (DTI) could serve as a potential biomarker for the assessment of radiation-induced long-term white matter injury. Material and methods. DTI- and T1-weighted images of the brain were obtained in 19 former radiotherapy patients [nine men and 10 women diagnosed with astrocytoma (4), pituitary adenoma (6), meningioma (8) and craniopharyngioma (1), average age 57.8 (range 35-71) years]. Average time from radiotherapy to DTI scan was 4.6 (range 2.0-7.1) years. NordicICE software (NIC) was used to calculate apparent diffusion coefficient maps (ADC-maps). The co-registration between T1 images and ADC-maps were done using the auto function in NIC. The co-registration between the T1 images and the patient dose plans were done using the auto function in the treatment planning system Eclipse from Varian. Regions of interest were drawn on the T1-weighted images in NIC based on isocurves from Eclipse. Data was analysed by t-test. Estimates are given with 95% CI. Results. A mean ADC difference of 4.6(0.3;8.9)× 10(-5) mm(2)/s, p = 0.03 was found between paired white matter structures with a mean dose difference of 31.4 Gy. Comparing the ADC-values of the areas with highest dose from the paired data (dose > 33 Gy) with normal white matter (dose < 5 Gy) resulted in a mean dose difference of 44.1 Gy and a mean ADC difference of 7.87(3.15;12.60)× 10(-5) mm(2)/s, p = 0.003. Following results were obtained when looking at differences between white matter mean ADC in average dose levels from 5 to 55 Gy in steps of 10 Gy with normal white matter mean ADC: 5 Gy; 1.91(-1.76;5.58)× 10(-5) mm(2)/s, p = 0.29; 15 Gy; 5.81(1.53;10.11)× 10(-5) mm(2)/s, p = 0.01; 25 Gy; 5.80(2.43;9.18)× 10(-5) mm(2)/s, p = 0.002; 35 Gy; 5.93(2.89;8.97)× 10(-5) mm(2)/s, p = 0.0007; 45 Gy; 4.32(-0.24;8.89)× 10(-5) mm(2)/s, p = 0.06; 55 Gy; -4.04(-14.96;6.89)× 10(-5) mm(2)/s, p = 0.39. Conclusion. The results indicate that the structural integrity of white matter, assessed by ADC-values based on DTI, undergoes changes after radiation therapy starting as early as total dose levels between 5 and 15 Gy. PMID:23981047

Ravn, Søren; Holmberg, Mats; Sørensen, Preben; Frøkjær, Jens Brøndum; Carl, Jesper

2013-08-28

333

Vascular incontinence: incontinence in the elderly due to ischemic white matter changes  

PubMed Central

This review article introduces the new concept of vascular incontinence, a disorder of bladder control resulting from cerebral white matter disease (WMD). The concept is based on the original observation in 1999 of a correlation between the severity of leukoareosis or WMD, urinary symptoms, gait disorder and cognitive impairment. Over the last 20 years, the realization that WMD is not a benign incidental finding in the elderly has become generally accepted and several studies have pointed to an association between geriatric syndromes and this type of pathology. The main brunt of WMD is in the frontal regions, a region recognized to be crucial for bladder control. Other disorders should be excluded, both neurological and urological, such as normal-pressure hydrocephalus, progressive supranuclear palsy, etc., and prostatic hyperplasia, physical stress incontinence, nocturnal polyuria, etc. Treatment involves management of small vessel disease risk factors and anticholinergic drugs that do not easily penetrate the blood brain barrier to improve bladder control.

Sakakibara, Ryuji; Panicker, Jalesh; Fowler, Clare J; Tateno, Fuyuki; Kishi, Masahiko; Tsuyuzaki, Yohei; Ogawa, Emina; Uchiyama, Tomoyuki; Yamamoto, Tatsuya

2012-01-01

334

Atlas-based whole brain white matter analysis using large deformation diffeomorphic metric mapping: Application to normal elderly and Alzheimer's disease participants  

PubMed Central

The purpose of this paper is to establish single-participant white matter atlases based on diffusion tensor imaging. As one of the applications of the atlas, automated brain segmentation was performed and the accuracy was measured using Large Deformation Diffeomorphic Metric Mapping (LDDMM). High-quality diffusion tensor imaging (DTI) data from a single-participant were B0-distortion-corrected and transformed to the ICBM-152 atlas or to Talairach coordinates. The deep white matter structures, which have been previously well documented and clearly identified by DTI, were manually segmented. The superficial white matter areas beneath the cortex were defined, based on a population-averaged white matter probability map. The white matter was parcellated into 176 regions based on the anatomical labeling in the ICBM-DTI-81 atlas. The automated parcellation was achieved by warping this parcellation map to normal controls and to Alzheimer’s disease patients with severe anatomical atrophy. The parcellation accuracy was measured by a kappa analysis between the automated and manual parcellation at 11 anatomical regions. The kappa values were 0.70 for both normal controls and patients while the inter-rater reproducibility was 0.81 (controls) and 0.82 (patients), suggesting “almost perfect” agreement. A power analysis suggested that the proposed method is suitable for detecting FA and size abnormalities of the white matter in clinical studies.

Oishi, Kenichi; Faria, Andreia; Jiang, Hangyi; Li, Xin; Akhter, Kazi; Zhang, Jiangyang; Hsu, John T.; Miller, Michael I.; van Zijl, Peter C.M.; Albert, Marilyn; Lyketsos, Constantine G.; Woods, Roger; Toga, Arthur W.; Pike, G. Bruce; Rosa-Neto, Pedro; Evans, Alan; Mazziotta, John; Mori, Susumu

2010-01-01

335

In vivo Diffusion Tensor Imaging of Amyloid-?-Induced White Matter Damage in Mice.  

PubMed

Background: Diffusion tensor imaging (DTI) suggests the presence of white matter abnormality at the prodromal stage in human Alzheimer's disease (AD). Objective: To use a mouse model of AD to determine whether the white matter abnormality detected by in vivo DTI is associated with functional deficits and axon damage. Methods: Amyloid-?1-42 (A?1-42) was injected into the left lateral ventricle in mice. Two months after the injection, in vivo DTI and visual evoked potential (VEP) recordings were performed, followed by immunohistochemistry of phosphorylated neurofilament and myelin basic protein. Results: DTI of A?1-42-treated mice showed a significant increase of radial diffusivity in white matter including the optic nerves and tracts. The abnormality was associated with decreased amplitude and increased latency of VEP. Immunohistochemistry confirmed a significant loss of axons and myelin integrity. Conclusion: White matter damage induced by A?1-42 in mice can be detected non-invasively by DTI. PMID:24077431

Sun, Shu-Wei; Liang, Hsiao-Fang; Mei, Jennifer; Xu, Dan; Shi, Wei-Xing

2014-01-01

336

Stereotaxic White Matter Atlas Based on Diffusion Tensor Imaging in an ICBM Template  

PubMed Central

Brain registration to a stereotaxic atlas is an effective way to report anatomic locations of interest and to perform anatomic quantification. However, existing stereotaxic atlases lack comprehensive coordinate information about white matter structures. In this paper, white matter specific atlases in stereotaxic coordinates are introduced. As a reference template, the widely-used ICBM-152 was used. The atlas contains fiber orientation maps and hand-segmented white matter parcellation maps based on diffusion tensor imaging (DTI). Registration accuracy by linear and nonlinear transformation was measured, and automated template-based white matter parcellation was tested. The results showed high correlation between the manual ROI-based and the automated approaches for normal adult populations. The atlases are freely available and believed to be a useful resource as a target template and for automated parcellation methods.

Mori, Susumu; Oishi, Kenichi; Jiang, Hangyi; Jiang, Li; Li, Xin; Akhter, Kazi; Hua, Kegang; Faria, Andreia V.; Mahmood, Asif; Woods, Roger; Toga, Arthur; Pike, Bruce; Neto, Pedro Rosa; Evans, Alan; Zhang, Jiangyang; Huang, Hao; Miller, Michael I.; Zijl, Peter van; Mazziotta, John

2008-01-01

337

Cocaine addiction: diffusion tensor imaging study of the inferior frontal and anterior cingulate white matter.  

PubMed

Inferior frontal and anterior cingulate white matter integrity in 32 cocaine-dependent subjects was compared with that in 33 age-matched healthy control subjects. Diffusion tensor imaging data were acquired with a 1.5-T magnetic resonance imaging system. Cocaine-dependent subjects presented significantly lower fractional anisotropy values in inferior frontal white matter at the anterior-posterior commissure plane and higher anterior cingulate white matter values than control subjects. White matter integrity was also associated with impulsivity and motivation to change (Readiness to Change Questionnaire). These findings support the hypothesis that cocaine dependence involves a disruption of orbitofrontal connectivity and suggest that the anterior cingulate brain area might play a role in the motivation to change. PMID:19959341

Romero, Maria J; Asensio, Samuel; Palau, Carmina; Sanchez, Amparo; Romero, Francisco J

2010-01-30

338

Inter-Parietal White Matter Development Predicts Numerical Performance in Young Children.  

PubMed

In an effort to understand the role of interhemispheric transfer in numerical development, we investigated the relationship between children's developing knowledge of numbers and the integrity of their white matter connections between the cerebral hemispheres (the corpus callosum). We used diffusion tensor imaging (DTI) tractography analyses to test the link between the development of the corpus callosum and performance on symbolic and non-symbolic numerical judgment tasks. We were especially interested in the interhemispheric connections of parietal cortex in 6-year-old children, because regions of parietal cortex have been implicated in the development of numerical skills by several prior studies. Our results revealed significant structural differences between children and adults in the fibers of the corpus callosum connecting the left and right parietal lobes. Importantly, these structural differences were predictive of individual differences among children in performance on numerical judgment tasks: children with poor numerical performance relative to their peers exhibited reduced white matter coherence in the fibers passing through the isthmus of the corpus callosum, which connects the parietal hemispheres. PMID:22180720

Cantlon, Jessica F; Davis, Simon W; Libertus, Melissa E; Kahane, Jill; Brannon, Elizabeth M; Pelphrey, Kevin A

2011-12-01

339

Inter-Parietal White Matter Development Predicts Numerical Performance in Young Children  

PubMed Central

In an effort to understand the role of interhemispheric transfer in numerical development, we investigated the relationship between children’s developing knowledge of numbers and the integrity of their white matter connections between the cerebral hemispheres (the corpus callosum). We used diffusion tensor imaging (DTI) tractography analyses to test the link between the development of the corpus callosum and performance on symbolic and non-symbolic numerical judgment tasks. We were especially interested in the interhemispheric connections of parietal cortex in 6-year-old children, because regions of parietal cortex have been implicated in the development of numerical skills by several prior studies. Our results revealed significant structural differences between children and adults in the fibers of the corpus callosum connecting the left and right parietal lobes. Importantly, these structural differences were predictive of individual differences among children in performance on numerical judgment tasks: children with poor numerical performance relative to their peers exhibited reduced white matter coherence in the fibers passing through the isthmus of the corpus callosum, which connects the parietal hemispheres.

Cantlon, Jessica F.; Davis, Simon W.; Libertus, Melissa E.; Kahane, Jill; Brannon, Elizabeth M.; Pelphrey, Kevin A.

2011-01-01

340

Soccer heading is associated with white matter microstructural and cognitive abnormalities.  

PubMed

Purpose: To investigate the association of soccer heading with subclinical evidence of traumatic brain injury. Materials and Methods: With institutional review board approval and compliance with HIPAA guidelines, 37 amateur soccer players (mean age, 30.9 years; 78% [29] men, 22% [eight] women) gave written informed consent and completed a questionnaire to quantify heading in the prior 12 months and lifetime concussions. Diffusion-tensor magnetic resonance (MR) imaging at 3.0 T was performed (32 directions; b value, 800 sec/mm(2); 2 × 2 × 2-mm voxels). Cognitive function was measured by using a computerized battery of tests. Voxelwise linear regression (heading vs fractional anisotropy [FA]) was applied to identify significant regional associations. FA at each location and cognition were tested for a nonlinear relationship to heading by using an inverse logit model that incorporated demographic covariates and history of concussion. Results: Participants had headed 32-5400 times (median, 432 times) over the previous year. Heading was associated with lower FA at three locations in temporo-occipital white matter with a threshold that varied according to location (885-1550 headings per year) (P < .00001). Lower levels of FA were also associated with poorer memory scores (P < .00001), with a threshold of 1800 headings per year. Lifetime concussion history and demographic features were not significantly associated with either FA or cognitive performance. Conclusion: Heading is associated with abnormal white matter microstructure and with poorer neurocognitive performance. This relationship is not explained by a history of concussion. © RSNA, 2013. PMID:23757503

Lipton, Michael L; Kim, Namhee; Zimmerman, Molly E; Kim, Mimi; Stewart, Walter F; Branch, Craig A; Lipton, Richard B

2013-06-11

341

Molecular changes in white matter adjacent to an active demyelinating lesion in early multiple sclerosis.  

PubMed

A stereotactic biopsy of a 17-year-old woman revealed an active inflammatory demyelinating lesion compatible with pattern III multiple sclerosis (MS) according to Lucchinetti et al. The biopsy included a white matter region distant from the active inflammatory demyelinating lesion with abnormal MRI signal, lacking histopathological signs of demyelination and/or oligodendrocyte apoptosis. Expression analysis of this area revealed a strong up-regulation of neuronal nitric oxide synthase (nNOS). Furthermore, detection of nitrotyrosine provided evidence for reactive nitrogen species (RNS)-mediated damage to oligodendrocytes. Concomitantly, genes involved in neuroprotection against oxidative stress such as heme oxygenase 1 were up-regulated. Even though a single case report, this study shows earliest molecular changes in white matter surrounding an actively demyelinating lesion during the first manifestation of MS, pointing toward a more widespread pathological process. Therapeutic targeting of the identified mechanisms of tissue injury might be crucial to prevent further lesion formation or secondary tissue damage. PMID:19016740

Zeis, Thomas; Probst, Alfonse; Steck, Andreas Johann; Stadelmann, Christine; Brück, Wolfgang; Schaeren-Wiemers, Nicole

2008-10-31

342

Atlas-Guided Tract Reconstruction for Automated and Comprehensive Examination of the White Matter Anatomy  

PubMed Central

Tractography based on diffusion tensor imaging (DTI) is widely used to quantitatively analyze the status of the white matter anatomy in a tract-specific manner in many types of diseases. This approach, however, involves subjective judgment in the tract-editing process to extract only the tracts of interest. This process, usually performed by manual delineation of regions of interest, is also time-consuming, and certain tracts, especially the short cortico-cortical association fibers, are difficult to reconstruct. In this paper, we propose an automated approach for reconstruction of a large number of white matter tracts. In this approach, existing anatomical knowledge about tract trajectories (called the Template ROI Set or TRS) were stored in our DTI-based brain atlas with 130 three-dimensional anatomical segmentations, which were warped non-linearly to individual DTI data. We examined the degree of matching with manual results for selected fibers. We established 30 TRSs to reconstruct 30 prominent and previously well-described fibers. In addition, TRSs were developed to delineate 29 short association fibers that were found in all normal subjects examined in this paper (N=20). Probabilistic maps of the 59 tract trajectories were created from the normal subjects and were incorporated into our image analysis tool for automated tract-specific quantification.

Zhang, Yajing; Zhang, Jiangyang; Oishi, Kenichi; Faria, Andreia V.; Jiang, Hangyi; Li, Xin; Akhter, Kazi; Rosa-Neto, Pedro; Pike, G. Bruce; Evans, Alan; Toga, Arthur W.; Woods, Roger; Mazziotta, John C.; Miller, Michael I.; van Zijl, Peter C. M.; Mori, Susumu

2010-01-01

343

Strength of default mode resting-state connectivity relates to white matter integrity in children.  

PubMed

A default mode network of brain regions is known to demonstrate coordinated activity during the resting state. While the default mode network is well characterized in adults, few investigations have focused upon its development. We scanned 9-13-year-old children with diffusion tensor imaging and resting-state functional magnetic resonance imaging. We identified resting-state networks using Independent Component Analysis and tested whether the functional connectivity between the medial prefrontal cortex (mPFC) and posterior cingulate cortex (PCC) depends upon the maturation of the underlying cingulum white matter tract. To determine the generalizability of this relationship, we also tested whether functional connectivity depends on white matter maturity between bilateral lateral prefrontal cortex (lateral PFC) within the executive control network. We found a positive relationship between mPFC-PCC connectivity and fractional anisotropy of the cingulum bundle; this positive relationship was moderated by the age of the subjects such that it was stronger in older children. By contrast, no such structure-function relationship emerged between right and left lateral PFC. However, functional and structural connectivity of this tract related positively with cognitive speed, fluency, and set-switching neuropsychological measures. PMID:21676094

Gordon, Evan M; Lee, Philip S; Maisog, Jose M; Foss-Feig, Jennifer; Billington, Michael E; Vanmeter, John; Vaidya, Chandan J

2010-12-09

344

Late Development of the GABAergic System in the Human Cerebral Cortex and White Matter  

PubMed Central

Despite the key role of ?-aminobutyric acid (GABA) neurons in the modulation of cerebral cortical output, little is known about their development in the human cortex. We analyzed several GABAergic parameters in standardized regions of the cerebral cortex and white matter in a total of 38 human fetuses and infants from 19 gestational weeks to 2.7 postnatal years utilizing immunocytochemistry, Western blotting, tissue autoradiography and computer-based cellular quantitation. At least 20% of GABAergic neurons in the white matter migrated toward the cortex over late gestation. After term, migration declined and ended within 6 postnatal months. In parallel, the GABAergic neuronal density increased in the cortex over late gestation, also with a peak at term. From midgestation to infancy, the pattern of GABAA receptor binding changed from uniformly low across all cortical layers to high levels concentrated in the middle laminae; glutamic acid decarboxylase (GAD65 and GAD67) levels differentially increased. Thus, the second half of gestation is a period of rapid development of the cortical GABAergic system that continues into early infancy. This time period corresponds to the peak window of vulnerability to perinatal hypoxia-ischemia in which GABAergic neurons are potentially developmentally susceptible, including in the preterm infant.

Xu, Gang; Broadbelt, Kevin G.; Haynes, Robin L.; Folkerth, Rebecca D.; Borenstein, Natalia S.; Belliveau, Richard A.; Trachtenberg, Felicia L.; Volpe, Joseph J.; Kinney, Hannah C.

2011-01-01

345

Psychological dysregulation, white matter disorganization and substance use disorders in adolescence  

PubMed Central

Aims Adolescents with substance use disorders (SUD) have difficulties with cognitive, behavioral and affective regulation. White matter (WM) disorganization has been observed in adolescents with SUD and may be related to psychological dysregulation. This study compared adolescents with SUD and control adolescents to investigate relationships among psychological dysregulation, WM disorganization, and SUD symptoms. Design Cross-sectional observation. Setting Adolescents with SUD were recruited from SUD treatment programs. Controls were recruited from the community. Participants The 55 participants were ages 14–19; 35 with SUD, 20 controls without SUD. Measurements Psychological dysregulation was characterized by the Behavior Rating Inventory of Executive Function. WM disorganization was measured by diffusion tensor imaging, and fractional anisotropy, radial diffusivity and axial diffusivity were examined within cortical regions of interest. Findings Compared to controls, SUD adolescents showed significantly greater psychological dysregulation and prefrontal and parietal WM disorganization. WM disorganization was positively correlated with psychological dysregulation and cannabis-related symptoms. In multivariate mediation models, the results were consistent with both the Neurodevelopmental Immaturity model, in which WM disorganization leads to psychological dysregulation and cannabis-related symptoms, and with the Substance Effects Model, in which cannabis-related symptoms lead to WM disorganization and psychological dysregulation. Conclusions In adolescents, substance use disorder and psychological dysregulation appear to be associated with reduced frontoparietal network white matter maturation.

Clark, Duncan B.; Chung, Tammy; Thatcher, Dawn L.; Pajtek, Stefan; Long, Elizabeth C.

2011-01-01

346

White matter tractography based on minimizing the tracking cost model from diffusion tensor MRI  

NASA Astrophysics Data System (ADS)

Diffusion tensor magnetic resonance imaging (DT-MRI) provides information about fiber direction in brain white matter and can be used for neuronal fiber pathways tracking. The purpose of our study is to develop and evaluate a novel approach for tracing anatomical fibers in vivo human brain from 3D DT-MRI tensor fields. The scheme is divided into two steps: regularization of tensor fields and fiber tracking. Firstly, 3D tensor fields are regularized to preserve directional information and discontinuous features, while removing uncorrelated noise from the data. Secondly, initiated from an operator-selected region, the anatomical fibers are bidirectionally traced based on minimizing the tracking cost (MTC) model. The model computes the possible direction of tract propagation, allowing a global trade-off among the entire tensor data, a prior knowledge of low curvature, and tracking inertia, instead of just the major eigenvector. Analysis on simulated data showed that the proposed method is less sensitive to image noise and partial volume effect than tracking using the major eigenvector, and overcomes the problem of fiber crossing successfully. Various estimated tracts obtained from human brain DT-MRI data showed that the proposed approach improves the reliability and robustness of fiber tractography. The proposed approach is effective and reproducible, which is promising for mapping the organizational patterns of white matter in the human brain as well as mapping the relationship between major fiber trajectories and the location and extent of brain lesions.

Li, Wu; Tian, Jie; Dai, Jianping

2004-05-01

347

White Matter Microstructural Correlates of Superior Long-term Skill Gained Implicitly under Randomized Practice  

PubMed Central

We value skills we have learned intentionally, but equally important are skills acquired incidentally without ability to describe how or what is learned, referred to as implicit. Randomized practice schedules are superior to grouped schedules for long-term skill gained intentionally, but its relevance for implicit learning is not known. In a parallel design, we studied healthy subjects who learned a motor sequence implicitly under randomized or grouped practice schedule and obtained diffusion-weighted images to identify white matter microstructural correlates of long-term skill. Randomized practice led to superior long-term skill compared with grouped practice. Whole-brain analyses relating interindividual variability in fractional anisotropy (FA) to long-term skill demonstrated that 1) skill in randomized learners correlated with FA within the corticostriatal tract connecting left sensorimotor cortex to posterior putamen, while 2) skill in grouped learners correlated with FA within the right forceps minor connecting homologous regions of the prefrontal cortex (PFC) and the corticostriatal tract connecting lateral PFC to anterior putamen. These results demonstrate first that randomized practice schedules improve long-term implicit skill more than grouped practice schedules and, second, that the superior skill acquired through randomized practice can be related to white matter microstructure in the sensorimotor corticostriatal network.

Song, Sunbin; Sharma, Nikhil; Buch, Ethan R.

2012-01-01

348

Cerebral microbleeds and white matter changes in patients hospitalized with lacunar infarcts  

Microsoft Academic Search

Microbleeds (MBs) detected by gradient-echo T2*-weighted MRI (GRE-T2*),white matter changes and lacunar infarcts may be regarded as manifestations of microangiopathy. The establishment of a quantitative relationship among them would further strengthen this hypothesis. We aimed to investigate the frequency and the number of MBs in patients hospitalized with lacunar infarcts and their quantitative relationship with the severity of white matter

YuHua Fan; Vincent C. T. Mok; Wynnie W. M. Lam; Andrew C. F. Hui; KaSing Wong

2004-01-01

349

Infant cerebellar gray and white matter fatty acids in relation to age and diet  

Microsoft Academic Search

There is little evidence as to the fatty acid composition of the cerebellum in infancy and it remains uncertain whether milk\\u000a diet can influence its composition. We therefore examined cerebellar gray and white matter of infants less than 6 mon old\\u000a who had died unexpectedly. The fatty acid content of 33 gray and 21 white matter specimens from infants born

E. C. Jamieson; J. Farquharson; R. W. Logan; A. G. Howatson; W. J. A. Patrick; L. T. Weaver; F. Cockburn

1999-01-01

350

Impact of White Matter Changes on Clinical Manifestation of Alzheimer's Disease A Quantitative Study  

Microsoft Academic Search

Background and Purpose—There have been conflicting results involving the clinical significance of white matter changes in patients with Alzheimer's disease (AD). We studied the association between the volume of white matter hyperintensities (WMHs) on T2-weighted images and cognitive, neurological, and neuropsychiatric symptoms. Methods—The subjects were 76 AD patients who had WMHs but no obvious cerebrovascular diseases. We quantified the volume

Nobutsugu Hirono; Hajime Kitagaki; Hiroaki Kazui; Mamoru Hashimoto; Etsuro Mori

351

Assessing the effects of age on long white matter tracts using diffusion tensor tractography  

PubMed Central

Aging is associated with significant white matter deterioration and this deterioration is assumed to be at least partly a consequence of myelin degeneration. The present study investigated specific predictions of the myelodegeneration hypothesis using diffusion tensor tractography. This technique has several advantages over other methods of assessing white matter architecture, including the possibility of isolating individual white matter tracts and measuring effects along the whole extent of each tract. The study yielded three main findings. First, age-related white matter deficits increased gradually from posterior to anterior segments within specific fiber tracts traversing frontal and parietal, but not temporal cortex. This pattern inverts the sequence of myelination during childhood and early development observed in previous studies and lends support to a “last-in-first-out” theory of the white matter health across the lifespan. Second, both the effects aging on white matter and their impact on cognitive performance were stronger for radial diffusivity (RD) than for axial diffusivity (AD). Given that RD has previously been shown to be more sensitive to myelin integrity than AD, this second finding is also consistent with the myelodegeneration hypothesis. Finally, the effects of aging on select white matter tracts were associated with age difference in specific cognitive functions. Specifically, FA in anterior tracts was shown to be primarily associated with executive tasks and FA in posterior tracts mainly associated with visual memory tasks. Furthermore, these correlations were mirrored in RD, but not AD, suggesting that RD is more sensitive to age-related changes in cognition. Taken together, the results help to clarify how age-related white matter decline impairs cognitive performance.

Davis, Simon W.; Dennis, Nancy A.; Buchler, Norbou G.; White, Leonard E.; Madden, David J.; Cabeza, Roberto

2009-01-01

352

Breakdown of Calcium Homeostasis in Relation to Tissue Depolarization: Comparison Between Gray and White Matter Ischemia  

Microsoft Academic Search

In vitro studies suggest that ischemic injury of cerebral white matter is mediated by nonsynaptic cellular mechanisms, such as Ca2+ entry into axons through reversal of the Na+-Ca2+ exchanger. The authors investigated extracellular Ca2+ concentration in relation to tissue depolarization (direct current potential) in vivo using ion-selective electrodes in cortical gray and subcortical white matter of ?-chloralose-anesthetized cats during 120

E. Kumura; R. Graf; C. Dohmen; G. Rosner; W. D. Heiss

1999-01-01

353

Default-mode network connectivity and white matter burden in late-life depression  

Microsoft Academic Search

The brain's default-mode network has been the focus of intense research. This study characterizes the default-mode network activity in late-life depression and the correlation of the default-mode network activity changes with the white-matter hyperintensities burden. We hypothesized that elderly depressed subjects would have altered default-mode network activity, which would correlate with the increased white-matter hyperintensities burden. Twelve depressed subjects (mean

Minjie Wu; Carmen Andreescu; Meryl A. Butters; Robert Tamburo; Charles F. Reynolds; Howard Aizenstein

2011-01-01

354

White matter tract injury and cognitive impairment in human immunodeficiency virus-infected individuals  

PubMed Central

Approximately half of those infected with the human immunodeficiency virus (HIV) exhibit cognitive impairment, which has been related to cerebral white matter damage. Despite the effectiveness of antiretroviral treatment, cognitive impairment remains common even in individuals with undetectable viral loads. One explanation for this may be subtherapeutic concentrations of some antiretrovirals in the central nervous system (CNS). We utilized diffusion tensor imaging and a comprehensive neuropsychological evaluation to investigate the relationship of white matter integrity to cognitive impairment and antiretroviral treatment variables. Participants included 39 HIV-infected individuals (49% with acquired immunodeficiency syndrome [AIDS]; mean CD4=529) and 25 seronegative subjects. Diffusion tensor imaging indices were mapped onto a common whole-brain white matter tract skeleton, allowing between-subject voxelwise comparisons. The total HIV-infected group exhibited abnormal white matter in the internal capsule, inferior longitudinal fasciculus, and optic radiation; whereas those with AIDS exhibited more widespread damage, including in the internal capsule and the corpus callosum. Cognitive impairment in the HIV-infected group was related to white matter injury in the internal capsule, corpus callosum, and superior longitudinal fasciculus. White matter injury was not found to be associated with HIV viral load or estimated CNS penetration of antiretrovirals. Diffusion tensor imaging was useful in identifying changes in white matter tracts associated with more advanced HIV infection. Relationships between diffusion alterations in specific white matter tracts and cognitive impairment support the potential utility of diffusion tensor imaging in examining the anatomical underpinnings of HIV-related cognitive impairment. The study also confirms that CNS injury is evident in persons infected with HIV despite effective antiretroviral treatment.

Gongvatana, Assawin; Schweinsburg, Brian C; Taylor, Michael J; Theilmann, Rebecca J; Letendre, Scott L; Alhassoon, Omar M; Jacobus, Joanna; Woods, Steven P; Jernigan, Terry L; Ellis, Ronald J; Frank, Lawrence R; Grant, Igor

2011-01-01

355

Normal-Appearing White Matter Permeability Distinguishes Poor Cognitive Performance in Processing Speed and Working Memory.  

PubMed

BACKGROUND AND PURPOSE:Secondary-progressive MS is characterized by reduced acute inflammation and contrast enhancement but with increased axonal degeneration and cognitive/clinical disability that worsens with advanced disease. Relative recirculation, extracted from DSC is a surrogate measure of BBB integrity. We hypothesized that normal-appearing white matter relative recirculation is reduced in cognitively impaired compared with nonimpaired secondary-progressive MS, reflecting more advanced disease.MATERIALS AND METHODS:Cognitive performance was classified as impaired or nonimpaired by use of Minimal Assessment of Cognitive Function In MS test components. Demographic data, brain parenchymal fraction, WM lesion fraction, and weighted mean normal-appearing white matter relative recirculation were compared in cognitively dichotomized groups. Univariate and multivariate logistic regressions were used to study the association between cognitive test results and normal-appearing white matter relative recirculation.RESULTS:The mean (SD) age of 36 patients with secondary-progressive MS studied was 55.9 ± 9.3 years; 13 of 36 (36%) patients were male. A highly significant difference between normal-appearing white matter relative recirculation and WM lesion relative recirculation was present for all patients (P < .001). Normal-appearing white matter relative recirculation in impaired patients was significantly lower than in nonimpaired subjects for the Symbol Digit Modalities Test (P = .007), Controlled Word Association Test (P = .008), and Paced Auditory Serial Addition Test (P = .024). The Expanded Disability Status Scale demonstrated an inverse correlation with normal-appearing white matter relative recirculation (r = -0.319, P = .075). After adjustment for confounders, significant normal-appearing white matter relative recirculation reduction persisted for the Symbol Digit Modalities Test (P = .023) and the Paced Auditory Serial Addition Test (P = .047) but not for the Controlled Word Association Test (P = .13) in impaired patients.CONCLUSIONS:Significant normal-appearing white matter relative recirculation reduction exists in cognitively impaired patients with secondary-progressive MS, localizing to the domains of processing speed and working memory. PMID:23721894

Eilaghi, A; Kassner, A; Sitartchouk, I; Francis, P L; Jakubovic, R; Feinstein, A; Aviv, R I

2013-05-30

356

Diffusion Tensor Imaging of Frontal White Matter and Executive Functioning in Cocaine-Exposed Children  

Microsoft Academic Search

BACKGROUND. Although animal studies have demonstrated frontal white matter and behavioral changes resulting from prenatal cocaine exposure, no human studies have associated neuropsychological deficits in attention and inhibition with brain structure. We used diffusion tensor imaging to investigate frontal white matter integrity and executive functioning in cocaine-exposed children. METHODS.Six direction diffusion tensor images were acquired using a Siemens 3T scanner

Tamara Duckworth Warner; Marylou Behnke; Fonda Davis Eyler; Kyle Padgett; Christiana Leonard; Wei Hou; Cynthia Wilson Garvan; Ilona M. Schmalfuss; Stephen J. Blackband

2007-01-01

357

Less white matter concentration in autism: 2D voxel-based morphometry  

Microsoft Academic Search

Autism is a neurodevelopmental disorder affecting behavioral and social cognition, but there is little understanding about the link between the functional deficit and its underlying neuroanatomy. We applied a 2D version of voxel-based morphometry (VBM) in differentiating the white matter concentration of the corpus callosum for the group of 16 high functioning autistic and 12 normal subjects. Using the white

Moo K. Chung; Kim M. Dalton; Andrew L. Alexander; Richard J. Davidson

2004-01-01

358

White matter deficits in psychopathic offenders and correlation with factor structure.  

PubMed

Psychopathic offenders show a persistent pattern of emotional unresponsivity to the often horrendous crimes they perpetrate. Recent studies have related psychopathy to alterations in white matter. Therefore, diffusion tensor imaging followed by tract-based spatial statistics (TBSS) analysis in 11 psychopathic offenders matched to 11 healthy controls was completed. Fractional anisotropy was calculated within each voxel and comparisons were made between groups using a permutation test. Any clusters of white matter voxels different between groups were submitted to probabilistic tractography. Significant differences in fractional anisotropy were found between psychopathic offenders and healthy controls in three main white matter clusters. These three clusters represented two major networks: an amygdalo-prefrontal network, and a striato-thalamo-frontal network. The interpersonal/affective component of the PCL-R correlated with white matter deficits in the orbitofrontal cortex and frontal pole whereas the antisocial component correlated with deficits in the striato-thalamo-frontal network. In addition to replicating earlier work concerning disruption of an amygdala-prefrontal network, we show for the first time that white matter integrity in a striato-thalamo-frontal network is disrupted in psychopathic offenders. The novelty of our findings lies in the two dissociable white matter networks that map directly onto the two major factors of psychopathy. PMID:23977291

Hoppenbrouwers, Sylco S; Nazeri, Arash; de Jesus, Danilo R; Stirpe, Tania; Felsky, Daniel; Schutter, Dennis J L G; Daskalakis, Zafiris J; Voineskos, Aristotle N

2013-08-20

359

White matter network abnormalities are associated with cognitive decline in chronic epilepsy.  

PubMed

Patients with chronic epilepsy frequently display cognitive comorbidity and might have widespread network abnormalities outside the epileptic zone, which might affect a variety of cognitive functions and global intelligence. We aimed to study the role of white matter connectivity in cognitive comorbidity. Thirty-nine patients with nonsymptomatic localization-related epilepsy and varying degrees of cognitive impairment and 23 age-matched healthy controls were included. Whole brain white matter networks were constructed from fiber tractography. Weighted graph theoretical analysis was performed to study white matter network abnormalities associated with epilepsy and cognition. Patients with severe cognitive impairment showed lower clustering (a measure of brain network segregation) and higher path length (a measure of brain network integration) compared with the healthy controls and patients with little or no cognitive impairment, whereas whole brain white matter volume did not differ. Correlation analyses revealed that IQ and cognitive impairment were strongly associated with clustering and path lengths. This study revealed impaired white matter connectivity, associated with cognitive comorbidity in patients with chronic epilepsy. As whole brain white matter volumes were preserved in the patient group, our results suggest an important role for the network topology rather than volumetric changes, in epilepsy with cognitive decline. PMID:22038907

Vaessen, Maarten J; Jansen, Jacobus F A; Vlooswijk, Marielle C G; Hofman, Paul A M; Majoie, H J Marian; Aldenkamp, Albert P; Backes, Walter H

2011-10-29

360

Pain intensity and pain affect in relation to white matter changes.  

PubMed

Since aging is a risk factor for both dementia and the occurrence of painful conditions, with the number of aged people increasing in the next decades, an increase in the number of elderly people suffering from both conditions can be anticipated. Reliable pain assessment in this population is restricted by reduced communicative and cognitive capacity, with serious consequences for effective pain treatment. White matter changes are frequently observed in the various subtypes of dementia as well as in normal aging, and may play a crucial role in pain processing. In healthy elderly people, reliable pain assessment can be accomplished, which enables examining the relationship between pain experience and white matter changes. A normal structure and function of the white matter is extremely important for dorsolateral prefrontal cortex (DLPFC) functioning, which has recently been linked to pain inhibition. The present study focused on the relation between white matter changes and both pain intensity and pain affect in elderly people without dementia. The Coloured Analogue Scale (CAS) and the Number of Words Chosen-Affective (NWC-A) were applied to measure pain intensity and pain affect, respectively. The presence of white matter changes was significantly related to a higher score on the NWC-A but not the CAS score. These results suggest that pain experience may change as a result of aging and that white matter changes might be indicative for these alterations. PMID:16750299

Oosterman, Joukje M; van Harten, Barbera; Weinstein, Henry C; Scheltens, Philip; Scherder, Erik J A

2006-06-05

361

Effects of White Matter Injury on Resting State fMRI Measures in Prematurely Born Infants  

PubMed Central

The cerebral white matter is vulnerable to injury in very preterm infants (born prior to 30 weeks gestation), resulting in a spectrum of lesions. These range from severe forms, including cystic periventricular leukomalacia and periventricular hemorrhagic infarction, to minor focal punctate lesions. Moderate to severe white matter injury in preterm infants has been shown to predict later neurodevelopmental disability, although outcomes can vary widely in infants with qualitatively comparable lesions. Resting state functional connectivity magnetic resonance imaging has been increasingly utilized in neurodevelopmental investigations and may provide complementary information regarding the impact of white matter injury on the developing brain. We performed resting state functional connectivity magnetic resonance imaging at term equivalent postmenstrual age in fourteen preterm infants with moderate to severe white matter injury secondary to periventricular hemorrhagic infarction. In these subjects, resting state networks were identifiable throughout the brain. Patterns of aberrant functional connectivity were observed and depended upon injury severity. Comparisons were performed against data obtained from prematurely-born infants with mild white matter injury and healthy, term-born infants and demonstrated group differences. These results reveal structural-functional correlates of preterm white matter injury and carry implications for future investigations of neurodevelopmental disability.

Smyser, Christopher D.; Snyder, Abraham Z.; Shimony, Joshua S.; Blazey, Tyler M.; Inder, Terrie E.; Neil, Jeffrey J.

2013-01-01

362

Age-related abnormalities in white matter microstructure in autism spectrum disorders  

PubMed Central

Abnormalities in structural and functional connectivity have been reported in autism spectrum disorders (ASD) across a wide age range. However, developmental changes in white matter microstructure are poorly understood. We used a cross-sectional design to determine whether white matter abnormalities measured using diffusion tensor imaging (DTI) were present in adolescents and adults with ASD and whether age-related changes in white matter microstructure differed between ASD and typically developing (TD) individuals. Participants included 28 individuals with ASD and 33 TD controls matched on age and IQ and assessed at one time point. Widespread decreased fractional anisotropy (FA), and increased radial diffusivity (RaD) and mean diffusivity (MD) were observed in the ASD group compared to the TD group. In addition, significant group-by-age interactions were also observed in FA, RaD, and MD in all major tracts except the brain stem, indicating that age-related changes in white matter microstructure differed between the groups. We propose that white matter microstructural changes in ASD may reflect myelination and/or other structural differences including differences in axonal density/arborization. In addition, we suggest that white matter microstuctural impairments may be normalizing during young adulthood in ASD. Future longitudinal studies that include a wider range of ages and more extensive clinical characterization will be critical for further uncovering the neurodevelopmental processes unfolding during this dynamic time in development.

Kleinhans, Natalia M.; Pauley, Gregory; Richards, Todd; Neuhaus, Emily; Martin, Nathalie; Corrigan, Neva M.; Shaw, Dennis W.; Estes, Annette; Dager, Stephen R.

2012-01-01

363

Oligodendrocyte precursors induce early blood-brain barrier opening after white matter injury  

PubMed Central

Oligodendrocyte precursor cells (OPCs) are thought to maintain homeostasis and contribute to long-term repair in adult white matter; however, their roles in the acute phase after brain injury remain unclear. Mice that were subjected to prolonged cerebral hypoperfusion stress developed white matter demyelination over time. Prior to demyelination, we detected increased MMP9 expression, blood-brain barrier (BBB) leakage, and neutrophil infiltration in damaged white matter. Notably, at this early stage, OPCs made up the majority of MMP9-expressing cells. The standard MMP inhibitor GM6001 reduced the early BBB leakage and neutrophil infiltration, indicating that OPC-derived MMP9 induced early BBB disruption after white matter injury. Cell-culture experiments confirmed that OPCs secreted MMP9 under pathological conditions, and conditioned medium prepared from the stressed OPCs weakened endothelial barrier tightness in vitro. Our study reveals that OPCs can rapidly respond to white matter injury and produce MMP9 that disrupts the BBB, indicating that OPCs may mediate injury in white matter under disease conditions.

Seo, Ji Hae; Miyamoto, Nobukazu; Hayakawa, Kazuhide; Pham, Loc-Duyen D.; Maki, Takakuni; Ayata, Cenk; Kim, Kyu-Won; Lo, Eng H.; Arai, Ken

2013-01-01

364

Mapping joint grey and white matter reductions in Alzheimer's disease using joint independent component analysis.  

PubMed

Alzheimer's disease (AD) is a neurodegenerative disease concomitant with grey and white matter damages. However, the interrelationship of volumetric changes between grey and white matter remains poorly understood in AD. Using joint independent component analysis, this study identified joint grey and white matter volume reductions based on structural magnetic resonance imaging data to construct the covariant networks in twelve AD patients and fourteen normal controls (NC). We found that three networks showed significant volume reductions in joint grey-white matter sources in AD patients, including (1) frontal/parietal/temporal-superior longitudinal fasciculus/corpus callosum, (2) temporal/parietal/occipital-frontal/occipital, and (3) temporal-precentral/postcentral. The corresponding expression scores distinguished AD patients from NC with 85.7%, 100% and 85.7% sensitivity for joint sources 1, 2 and 3, respectively; 75.0%, 66.7% and 75.0% specificity for joint sources 1, 2 and 3, respectively. Furthermore, the combined source of three significant joint sources best predicted the AD/NC group membership with 92.9% sensitivity and 83.3% specificity. Our findings revealed joint grey and white matter loss in AD patients, and these results can help elucidate the mechanism of grey and white matter reductions in the development of AD. PMID:23123779

Guo, Xiaojuan; Han, Yuan; Chen, Kewei; Wang, Yan; Yao, Li

2012-11-02

365

A tract-specific framework for white matter morphometry combining macroscopic and microscopic tract features  

PubMed Central

Diffusion tensor imaging plays a key role in our understanding of white matter both in normal populations and in populations with brain disorders. Existing techniques focus primarily on using diffusivity-based quantities derived from diffusion tensor as surrogate measures of microstructural tissue properties of white matter. In this paper, we describe a novel tract-specific framework that enables the examination of white matter morphometry at both the macroscopic and microscopic scales. The framework leverages the skeleton-based modeling of sheet-like white matter fasciculi using the continuous medial representation, which gives a natural definition of thickness and supports its comparison across subjects. The thickness measure provides a macroscopic characterization of white matter fasciculi that complements existing analysis of microstructural features. The utility of the framework is demonstrated in quantifying white matter atrophy in Amyotrophic Lateral Sclerosis, a severe neurodegenerative disease of motor neurons. We show that, compared to using microscopic features alone, combining the macroscopic and microscopic features gives a more complete characterization of the disease.

Zhang, Hui; Awatea, Suyash P; Das, Sandhitsu R; Woo, John H; Melhem, Elias R; Gee, James C; Yushkevich, Paul A

2010-01-01