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1

Automated segmentation method of white matter and gray matter regions with multiple sclerosis lesions in MR images  

Microsoft Academic Search

Our purpose in this study was to develop an automated method for segmentation of white matter (WM) and gray matter (GM) regions\\u000a with multiple sclerosis (MS) lesions in magnetic resonance (MR) images. The brain parenchymal (BP) region was derived from\\u000a a histogram analysis for a T1-weighted image. The WM regions were segmented by addition of MS candidate regions, which were

Taiki Magome; Hidetaka Arimura; Shingo Kakeda; Daisuke Yamamoto; Yasuo Kawata; Yasuo Yamashita; Yoshiharu Higashida; Fukai Toyofuku; Masafumi Ohki; Yukunori Korogi

2011-01-01

2

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

3

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

4

White matter dementia  

PubMed Central

White matter dementia (WMD) is a syndrome introduced in 1988 to highlight the potential of cerebral white matter disorders to produce cognitive loss of sufficient severity to qualify as dementia. Neurologists have long understood that such a syndrome can occur, but the dominance of gray matter as the locus of higher function has strongly directed neurobehavioral inquiry to the cerebral cortex while white matter has received less attention. Contemporary neuroimaging has been crucial in enabling the recognition of white matter abnormalities in a host of disorders, and the correlation of these changes with cognitive performance. Comprising about half the brain, white matter is prominently or exclusively involved in well over 100 disorders, in each of which white matter dysfunction can potentially cause or contribute to dementia. Neuropsychological findings from ten categories of white matter disorder lead to a convergence of findings that document remarkable neurobehavioral commonality among the dementias produced. More recently, the syndrome of mild cognitive dysfunction (MCD) has been introduced to expand the concept of WMD by proposing a precursor syndrome related to early white matter neuropathology. WMD and MCD inform the understanding of how white matter contributes to normal and abnormal cognition, and the specific neuroanatomic focus of these syndromes may enhance the diagnosis and treatment of many disabling disorders that do not primarily implicate the cerebral cortex. Forming essential connections within widely distributed neural networks, white matter is critical for rapid and efficient information transfer that complements the information processing of gray matter. As neuroimaging continues to advance, further information on white matter structure can be expected, and behavioral neurology will play a central role in elucidating the functional significance of these emerging data. By emphasizing the contribution of myelinated systems to higher function, the study of white matter and cognition represents investigation of the basic neuroscience of human behavior.

2012-01-01

5

White-matter connectivity between face-responsive regions in the human brain.  

PubMed

Face recognition is of major social importance and involves highly selective brain regions thought to be organized in a distributed functional network. However, the exact architecture of interconnections between these regions remains unknown. We used functional magnetic resonance imaging to identify face-responsive regions in 22 participants and then employed diffusion tensor imaging with probabilistic tractography to establish the white-matter pathways between these functionally defined regions. We identified strong white-matter connections between the occipital face area (OFA) and fusiform face area (FFA), with a significant right-hemisphere predominance. We found no evidence for direct anatomical connections between FFA and superior temporal sulcus (STS) or between OFA and STS, contrary to predictions based on current cognitive models. Instead, our findings point to segregated processing along a ventral extrastriate visual pathway to OFA-FFA and another more dorsal system connected to STS and frontoparietal areas. In addition, early occipital areas were found to have direct connections to the amygdala, which might underlie a rapid recruitment of limbic brain areas by visual inputs bypassing more elaborate extrastriate cortical processing. These results unveil the structural neural architecture of the human face recognition system and provide new insights on how distributed face-responsive areas may work together. PMID:21893680

Gschwind, Markus; Pourtois, Gilles; Schwartz, Sophie; Van De Ville, Dimitri; Vuilleumier, Patrik

2012-07-01

6

Impact of regional white matter lesions on cognitive function in subcortical vascular cognitive impairment.  

PubMed

Objectives: Exact characterization and localization of white matter lesions (WMLs) as they relate and contribute to vascular cognitive impairment is highly debated. The purpose of this study was to investigate the impact of WML on cognitive function by using a new anatomy-based classification method. Methods: We detected WML accurately by using a three-dimensional fluid-attenuated inversion recovery (3D FLAIR) imaging technique and subsequently segmented WMLs by using an anatomy-based method. Participants included 56 consecutive patients diagnosed with subcortical vascular cognitive impairment (SubVCI). The volume of WMLs in different anatomic regions was measured. The volume of the hippocampus, the corpus callosum (CC), any lacunar infarcts, total gray matter (GM), and total brain volumes were also calculated. Results: Hippocampal (P ?=? 0·005) as well as temporal WML volumes (P ?=? 0·039) were both independently associated with mini-mental state examination (MMSE) score. Only the parietal WML volume (P ?=? 0·000) was independently associated with Montreal Cognitive Assessment (MoCA) score. Frontal WMLs were independently correlated with executive function. Occipital WMLs were independently associated with visuospatial and recall function. Language impairment was independently correlated with both parietal GM and parietal WML volume. Functions related to orientation were independently associated with parietal WML volume. Discussion: The volume of WMLs in the temporal region as well as in the hippocampus were both independently associated with MMSE score. For the MoCA score, however, only parietal WML volumes were independently correlated. White matter lesions within different anatomic regions were separately correlated with different subdomains of cognitive function. PMID:24641691

Ai, Qing; Pu, Yue-Hua; Sy, Christopher; Liu, Li-Ping; Gao, Pei-Yi

2014-05-01

7

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

PubMed Central

Background New onset Alzheimer’s 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 (WMH) on MRI, remains unclear. Objective To determine whether regional WMH and hippocampal volume predict incident AD in an epidemiological study. Design A longitudinal community-based epidemiological study of older adults from northern Manhattan. Setting The Washington Heights/Inwood Columbia Aging Project Participants Between 2005 and 2007, 717 non-demented participants received MRI scans. An average of 40.28 (SD=9.77) months later, 503 returned for follow-up clinical examination and 46 met criteria for incident dementia (45 with AD). Regional WMH 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 two measurements. Main outcome measures Incident Alzheimer’s disease. Results White matter hyperintensity volume in the parietal lobe predicted time to incident dementia (HR=1.194, p=0.031). Relative hippocampal volume did not predict incident dementia when considered alone (HR=0.419, p=0.768) or with the WMH measures included in the model (HR=0.302, p=0.701). Including hippocampal volume in the model did not notably alter the predictive utility of parietal lobe WMH (HR=1.197, p=0.049). Conclusion The findings highlight the regional specificity of the association of WMH with AD. It is not clear whether parietal WMH solely represent a marker for cerebrovascular burden or point to distinct injury compared to other regions. Future work should elucidate pathogenic mechanisms linking WMH and AD pathology.

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

2013-01-01

8

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

9

Regional White Matter Anisotropy and Reading Ability in Patients Treated for Pediatric Embryonal Tumors  

Microsoft Academic Search

Children treated with cranial irradiation for brain tumors have reduced white matter volume and deficits in reading ability.\\u000a This study prospectively examined the relationship between reading and white matter integrity within this patient group. Patients\\u000a (n?=?54) were treated with post-surgical radiation followed by 4 cycles of high-dose chemotherapy with stem cell support. At\\u000a 12 months post-diagnosis, all patients completed a

Shawna L. Palmer; Wilburn E. Reddick; John O. Glass; Robert Ogg; Zoltan Patay; Dana Wallace; Amar Gajjar

2010-01-01

10

Regional cerebral blood flow, white matter abnormalities, and cerebrospinal fluid hydrodynamics in patients with idiopathic adult hydrocephalus syndrome.  

PubMed

OBJECTIVES--(1) to evaluate regional cerebral blood flow (rCBF) with single photon emission computed tomography and 99mTc-hexamethylpropyleneamine oxime in patients with the idiopathic adult hydrocephalus syndrome (IAHS); (2) to examine regional cerebral blood flow (rCBF), gait, and psychometric functions before and after CSF removal (CSF tap test); (3) to assess abnormalities in subcortical white matter by MRI. METHODS--Thirty one patients fulfilling the criteria for IAHS (according to history and clinical and neuroradiological examination) were studied. Quantified gait measurements, psychometric testing, and rCBF before and after removal of CSF were obtained. Pressure of CSF and CSF outflow conductance were investigated with a constant pressure infusion method. Brain MRI was used to quantify the severity of white matter lesions and periventricular hyperintensities. In IAHS a widespread rCBF hypoperfusion pattern was depicted, with a caudal frontal and temporal grey matter and subcortical white matter reduction of rCBF as the dominant feature. Removal of CSF was not accompanied by a concomitant increase in rCBF. Significant white matter lesions were detected only in a minority of patients by MRI. An altered CSF hydrodynamic state with a higher CSF pressure and lower conductance was confirmed. IAHS is characterised by an abnormal CSF hydrodynamic state, associated with a widespread rCBF reduction with preference for subcortical white matter and frontal-temporal cortical regions. Furthermore in most patients MRI did not show white matter changes suggestive of a coexistent subcortical arteriosclerotic encephalopathy. At least in the idiopathic group of patients with AHS, measurements of rCBF before and after temporary relief of the CSF hydrodynamic disturbance will not provide additional information that would be helpful in the preoperative evaluation but is suggestive of a preserved autoregulation of rCBF. PMID:8609504

Kristensen, B; Malm, J; Fagerland, M; Hietala, S O; Johansson, B; Ekstedt, J; Karlsson, T

1996-03-01

11

Regional cerebral blood flow, white matter abnormalities, and cerebrospinal fluid hydrodynamics in patients with idiopathic adult hydrocephalus syndrome.  

PubMed Central

OBJECTIVES--(1) to evaluate regional cerebral blood flow (rCBF) with single photon emission computed tomography and 99mTc-hexamethylpropyleneamine oxime in patients with the idiopathic adult hydrocephalus syndrome (IAHS); (2) to examine regional cerebral blood flow (rCBF), gait, and psychometric functions before and after CSF removal (CSF tap test); (3) to assess abnormalities in subcortical white matter by MRI. METHODS--Thirty one patients fulfilling the criteria for IAHS (according to history and clinical and neuroradiological examination) were studied. Quantified gait measurements, psychometric testing, and rCBF before and after removal of CSF were obtained. Pressure of CSF and CSF outflow conductance were investigated with a constant pressure infusion method. Brain MRI was used to quantify the severity of white matter lesions and periventricular hyperintensities. In IAHS a widespread rCBF hypoperfusion pattern was depicted, with a caudal frontal and temporal grey matter and subcortical white matter reduction of rCBF as the dominant feature. Removal of CSF was not accompanied by a concomitant increase in rCBF. Significant white matter lesions were detected only in a minority of patients by MRI. An altered CSF hydrodynamic state with a higher CSF pressure and lower conductance was confirmed. IAHS is characterised by an abnormal CSF hydrodynamic state, associated with a widespread rCBF reduction with preference for subcortical white matter and frontal-temporal cortical regions. Furthermore in most patients MRI did not show white matter changes suggestive of a coexistent subcortical arteriosclerotic encephalopathy. At least in the idiopathic group of patients with AHS, measurements of rCBF before and after temporary relief of the CSF hydrodynamic disturbance will not provide additional information that would be helpful in the preoperative evaluation but is suggestive of a preserved autoregulation of rCBF.

Kristensen, B; Malm, J; Fagerland, M; Hietala, S O; Johansson, B; Ekstedt, J; Karlsson, T

1996-01-01

12

White matter of the brain  

MedlinePLUS

White matter is tissue found in the brain. It contains nerve fibers. Many of these nerve fibers (axons) are ... fat called myelin. The myelin gives the white matter it's color. Myelin acts as an insulator. It ...

13

Verbal Working Memory Performance Correlates with Regional White Matter Structures in the Frontoparietal Regions  

ERIC Educational Resources Information Center

Working memory is the limited capacity storage system involved in the maintenance and manipulation of information over short periods of time. Previous imaging studies have suggested that the frontoparietal regions are activated during working memory tasks; a putative association between the structure of the frontoparietal regions and working…

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

2011-01-01

14

Regional characterization of longitudinal DT-MRI to study white matter maturation of the early developing brain.  

PubMed

The human brain undergoes rapid and dynamic development early in life. Assessment of brain growth patterns relevant to neurological disorders and disease requires a normative population model of growth and variability in order to evaluate deviation from typical development. In this paper, we focus on maturation of brain white matter as shown in diffusion tensor MRI (DT-MRI), measured by fractional anisotropy (FA), mean diffusivity (MD), as well as axial and radial diffusivities (AD, RD). We present a novel methodology to model temporal changes of white matter diffusion from longitudinal DT-MRI data taken at discrete time points. Our proposed framework combines nonlinear modeling of trajectories of individual subjects, population analysis, and testing for regional differences in growth pattern. We first perform deformable mapping of longitudinal DT-MRI of healthy infants imaged at birth, 1 year, and 2 years of age, into a common unbiased atlas. An existing template of labeled white matter regions is registered to this atlas to define anatomical regions of interest. Diffusivity properties of these regions, presented over time, serve as input to the longitudinal characterization of changes. We use non-linear mixed effect (NLME) modeling where temporal change is described by the Gompertz function. The Gompertz growth function uses intuitive parameters related to delay, rate of change, and expected asymptotic value; all descriptive measures which can answer clinical questions related to quantitative analysis of growth patterns. Results suggest that our proposed framework provides descriptive and quantitative information on growth trajectories that can be interpreted by clinicians using natural language terms that describe growth. Statistical analysis of regional differences between anatomical regions which are known to mature differently demonstrates the potential of the proposed method for quantitative assessment of brain growth and differences thereof. This will eventually lead to a prediction of white matter diffusion properties and associated cognitive development at later stages given imaging data at early stages. PMID:23235270

Sadeghi, Neda; Prastawa, Marcel; Fletcher, P Thomas; Wolff, Jason; Gilmore, John H; Gerig, Guido

2013-03-01

15

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

16

Human brain white matter atlas: identification and assignment of common anatomical structures in superficial white matter.  

PubMed

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. PMID:18692144

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

2008-11-15

17

INTERINDIVIDUAL VARIATION IN BLOOD PRESSURE IS ASSOCIATED WITH REGIONAL WHITE MATTER INTEGRITY IN GENERALLY HEALTHY OLDER ADULTS  

PubMed Central

Prior studies have documented a range of brain changes that occur as a result of healthy aging as well as neural alterations due to profound dysregulation in vascular health such as extreme hypertension, cerebrovascular disease and stroke. In contrast, little information exists about the more transitionary state between the normal and abnormal physiology that contributes to vascular disease and cognitive decline. Specifically, little information exists with regard to the influence of systemic vascular physiology on brain tissue structure in older individuals with low risk for cerebrovascular disease and with no evidence of cognitive impairment. We examined the association between resting blood pressure and diffusion tensor imaging (DTI) indices of white matter microstructure in 128 healthy older adults (43–87 years) spanning the normotensive to moderate-severe hypertensive range. Mean arterial blood pressure (MABP) was related to diffusion measures in several regions of the brain with greatest associations in the anterior corpus callosum and lateral frontal, precentral, superior frontal, lateral parietal and precuneus white matter. Associations between white matter integrity and blood pressure remained when controlling for age, when controlling for white matter lesions, and when limiting the analyses to only normotensive, pharmacologically controlled and prehypertensive individuals. Of the diffusion measures examined, associations were strongest between MABP and radial diffusivity which may indicate that blood pressure has an influence on myelin structure. Associations between MABP and white matter integrity followed spatial patterns resembling those often attributed to the effects of chronological age, suggesting that systemic cerebrovascular health may play a role in neural tissue degeneration classically ascribed to aging. These results demonstrate the importance of the consideration of vascular physiology in studies of cognitive and neural aging, and that this significance extends to even the normotensive and medically controlled population. These data additionally suggest that optimal management of blood pressure may require consideration of the more subtle influence of vascular health on neural health in addition to the primary goal of prevention of a major cerebrovascular event.

Salat, David H.; Williams, Victoria J.; Leritz, Elizabeth C.; Schnyer, David M.; Rudolph, James L.; Lipsitz, Lewis A.; McGlinchey, Regina E.; Milberg, William P.

2011-01-01

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

2012-09-01

19

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

20

A voxel-based morphometry study of regional gray and white matter correlate of self-disclosure.  

PubMed

Self-disclosure is an important performance in human social communication. Generally, an individual is likely to have a good physical and mental health if he is prone to self-disclosure under stressful life events. However, as for now, little is known about the neural structure associated with self-disclosure. Therefore, in this study, we used voxel-based morphometry to explore regional gray matter volume (rGMV) and white matter volume (rWMV) associated with self-disclosure measured by the Jourard Self-disclosure Questionnaire in a large sample of college students. Results showed that individual self-disclosure was significantly and positively associated with rGMV of the left postcentral gyrus, which might be related to strengthen individual's ability of body feeling; while self-disclosure was significantly and negatively associated with rGMV of the right orbitofrontal cortex (OFC), which might be involved in increased positive emotion experience seeking (intrinsically rewarding). In addition, individual self-disclosure was also associated with smaller rWMV in the right inferior parietal lobule (IPL). These findings suggested a biological basis for individual self-disclosure, distributed across different gray and white matter areas of the brain. PMID:24899238

Wang, ShanShan; Wei, DongTao; Li, WenFu; Li, HaiJiang; Wang, KangCheng; Xue, Song; Zhang, Qinglin; Qiu, Jiang

2014-10-01

21

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

22

Longitudinal absolute metabolite quantification of white and gray matter regions in healthy controls using proton MR spectroscopic imaging.  

PubMed

The purpose of this study was to evaluate quality parameters, metabolite concentrations and concentration ratios, and to investigate the reproducibility of quantitative proton magnetic resonance spectroscopic imaging ((1)H-MRSI) of selected white and gray matter regions of healthy adults. 2D-quantitative short-TE (1)H-MRSI spectra were obtained at 1.5T from the healthy human brain. Subjects (n?=?12) were scanned twice with an interval of six months. Absolute metabolite concentrations were obtained based on coil loading, taking into account differences in sensitivity of the phased-array head coil. Spectral quality parameters, absolute metabolite concentrations, concentration ratios, and their reproducibility were determined and compared between time-points using a repeated measures general linear model. The quality of the spectra of selected brain areas was good, as determined by a mean spectral linewidth between 4.8 and 7.3 Hz (depending on the region). No significant differences between the two time-points were observed for spectral quality, concentrations, or concentration ratios. The mean intrasubject coefficient of variation (CoV) varied between 4.0 and 8.5% for total N-acetylaspartate, 7.2 and 10.8% for total creatine, 5.9 and 9.8% for myo-inositol, and 8.0 and 13.3% for choline, and remained below 20% for glutamate. CoV was generally lower when concentration ratios were considered. The study shows that longitudinal quantitative short-TE (1)H-MRSI generates reproducible absolute metabolite concentrations in healthy human white and gray matter. This may serve as a background for longitudinal clinical studies in adult patients. PMID:24399803

Wiebenga, Oliver T; Klauser, Antoine M; Nagtegaal, Gijsbert J A; Schoonheim, Menno M; Barkhof, Frederik; Geurts, Jeroen J G; Pouwels, Petra J W

2014-03-01

23

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

24

On Describing Human White Matter Anatomy: The White Matter Query Language  

PubMed Central

The main contribution of this work is the careful syntactical definition of major white matter tracts in the human brain based on a neuroanatomist’s expert knowledge. We present a technique to formally describe white matter tracts and to automatically extract them from diffusion MRI data. The framework is based on a novel query language with a near-to-English textual syntax. This query language allows us to construct a dictionary of anatomical definitions describing white matter tracts. The definitions include adjacent gray and white matter regions, and rules for spatial relations. This enables automated coherent labeling of white matter anatomy across subjects. We use our method to encode anatomical knowledge in human white matter describing 10 association and 8 projection tracts per hemisphere and 7 commissural tracts. The technique is shown to be comparable in accuracy to manual labeling. We present results applying this framework to create a white matter atlas from 77 healthy subjects, and we use this atlas in a proof-of-concept study to detect tract changes specific to schizophrenia.

Wassermann, Demian; Makris, Nikos; Rathi, Yogesh; Shenton, Martha; Kikinis, Ron; Kubicki, Marek; Westin, Carl-Fredrik

2014-01-01

25

Isolated mild white matter signal changes in preterm infants: a regional approach for comparison of cranial ultrasound and MRI findings.  

PubMed

Objective:To compare echogenicity detected using cranial ultrasound (cUS) and diffuse excessive high signal intensity (DEHSI) detected using magnetic resonance imaging (MRI) by identical region-based scoring criteria in preterm infants. To explore the association between these white matter (WM) signal changes with early neurobehavior.Study Design:Forty-nine pre-selected premature infants with only echogenicity on a first routine cUS1 underwent MRI and a repeated cUS2 at term equivalent age. Echogenicity and DEHSI were graded in various brain areas and diffusivity values were calculated. Neurobehavior was assessed using the Rapid Neonatal Neurobehavioral Assessment Procedure.Result:WM signal changes were significantly higher on cUS1 than cUS2; and higher in MRI than cUS2 in posterior regions. Infants with DEHSI demonstrated reduced tissue integrity. Imaging findings were not correlated with early neurobehavior.Conclusion:Echogenicity and DEHSI likely represent the same phenomenon. Reduction of over-interpretation of WM signal changes may help define criteria for the judicious use of imaging in routine follow-up of premature infants. PMID:24651736

Weinstein, M; Ben Bashat, D; Gross-Tsur, V; Leitner, Y; Berger, I; Marom, R; Geva, R; Uliel, S; Ben-Sira, L

2014-06-01

26

An exploratory study on the spatial relationship between regional cortical volume changes and white matter integrity in multiple sclerosis.  

PubMed

Multiple sclerosis (MS) is a chronic inflammatory central nervous system disorder with a neurodegenerative component. While in the past, MS has been predominantly viewed as a white matter (WM) disease, gray matter (GM) pathology receives increasing attention in MS research. In this study, we tested hypothesis-free for a possible spatial relationship between cortical volume changes and disturbed integrity of projecting WM tracts. We used voxel-based morphometry (VBM), lesion probability maps (LPM), and probabilistic tractography to compare brain magnetic resonance imaging (MRI) scans obtained at 3 Tesla of 15 low disabled MS patients with 15 matched healthy controls (HCs). Areas of decreased cortical volume in the patients identified by VBM were used as seeds for tractography. Volume in two cortical areas in the left inferior frontal gyrus (IFG) and the left lateral occipital cortex (LOC) was reduced in patients compared to HCs. Starting from the IFG-region, tractography suggested impaired connections between left and right portions of the frontal lobe in the patients. Using the LOC as a seed, in patients, the left inferior longitudinal and fronto-occipital pathways appeared disintegrated compared to HCs. Swapping the seeds to homologous contralateral areas showed similar results for frontal, but different results for occipital brain areas. This at least partly could be explained by differential interference with WM lesions. These findings suggest a regional dependence between cortical GM and WM tract alterations in MS patients. While confirmation in larger and more heterogenic samples is needed, this study indicates that combining several MRI methods (VBM, LPM, and Probabilistic Tractography) may provide important insights into interacting processes related to the fiber tract and GM changes in MS. PMID:23573900

Jehna, Margit; Langkammer, Christian; Khalil, Michael; Fuchs, Siegrid; Reishofer, Gernot; Fazekas, Franz; Ebner, Franz; Enzinger, Christian

2013-01-01

27

White matter disintegration in cluster headache  

PubMed Central

Background Previous studies in primary headache disorders showed microstructural alterations in the white matter as measured by diffusion imaging. However these investigations are not in full agreement and some of those, especially in cluster headache, restricted the analysis to only a limited number of diffusion parameters. Therefore, in the current study we examined white matter microstructure in cluster headache patients. Methods Diffusion weighted MRI images with 60 directions were acquired from thirteen patients with cluster headache and sixteen age-matched healthy controls. Tract based spatial statistics were used to compare white matter integrity in the core of the fibre bundles. Correlation of the diffusion parameters with cumulative number of headache days was examined. Results There was a significant increment of the mean, axial and perpendicular diffusivity in widespread white matter regions in the frontal, parietal, temporal and occipital lobes. Reduced fractional anisotropy was found in the corpus callosum and some frontal and parietal white matter tracts mainly in the contralateral side of the pain. Axial diffusivity showed negative correlation to the number of the headache attacks. Conclusions The in vivo analysis of microstructural alterations in cluster headache provides important features of the disease, which might offer a deeper insight into the pathomechanism of the disease.

2013-01-01

28

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

29

Regional electric field induced by electroconvulsive therapy in a realistic finite element head model: Influence of white matter anisotropic conductivity  

PubMed Central

We present the first computational study investigating the electric field (E-field) strength generated by various electroconvulsive therapy (ECT) electrode configurations in specific brain regions of interest (ROIs) that have putative roles in the therapeutic action and/or adverse side effects of ECT. This study also characterizes the impact of the white matter (WM) conductivity anisotropy on the E-field distribution. A finite element head model incorporating tissue heterogeneity and WM anisotropic conductivity was constructed based on structural magnetic resonance imaging (MRI) and diffusion tensor MRI data. We computed the spatial E-field distributions generated by three standard ECT electrode placements including bilateral (BL), bifrontal (BF), and right unilateral (RUL) and an investigational electrode configuration for focal electrically administered seizure therapy (FEAST). The key results are that (1) the median E-field strength over the whole brain is 3.9, 1.5, 2.3, and 2.6 V/cm for the BL, BF, RUL, and FEAST electrode configurations, respectively, which coupled with the broad spread of the BL E-field suggests a biophysical basis for observations of superior efficacy of BL ECT compared to BF and RUL ECT; (2) in the hippocampi, BL ECT produces a median E-field of 4.8 V/cm that is 1.5–2.8 times stronger than that for the other electrode configurations, consistent with the more pronounced amnestic effects of BL ECT; and (3) neglecting the WM conductivity anisotropy results in E-field strength error up to 18% overall and up to 39% in specific ROIs, motivating the inclusion of the WM conductivity anisotropy in accurate head models. This computational study demonstrates how the realistic finite element head model incorporating tissue conductivity anisotropy provides quantitative insight into the biophysics of ECT, which may shed light on the differential clinical outcomes seen with various forms of ECT, and may guide the development of novel stimulation paradigms with improved risk/benefit ratio.

Lee, Won Hee; Deng, Zhi-De; Kim, Tae-Seong; Laine, Andrew F.; Lisanby, Sarah H.; Peterchev, Angel V.

2012-01-01

30

Cerebral white matter deficiencies in pedophilic men.  

PubMed

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

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

2008-02-01

31

Mobile NBM - android medical mobile application designed to help in learning how to identify the different regions of interest in the brain's white matter  

PubMed Central

Background One of the most critical tasks when conducting neurological studies is identifying the different regions of interest in the brain’s white matter. Currently few programs or applications are available that serve as an interactive guide in this process. This is why a mobile application has been designed and developed in order to teach users how to identify the referred regions of the brain. It also enables users to share the results obtained and take an examination on the knowledge thus learnt. In order to provide direct user-user or user-developer contact, the project includes a website and a Twitter account. Results An application has been designed with a basic, minimalist look, which anyone can access easily in order to learn to identify a specific region in the brain’s white matter. A survey has also been conducted on people who have used it, which has shown that the application is attractive both in the student (final mean satisfaction of 4.2/5) and in the professional (final mean satisfaction of 4.3/5) environment. The response obtained in the online part of the project reflects the high practical value and quality of the application, as shown by the fact that the website has seen a large number of visitors (over 1000 visitors) and the Twitter account has a high number of followers (over 280 followers). Conclusions Mobile NBM is the first mobile application to be used as a guide in the process of identifying a region of interest in the brain’s white matter. Although initially not many areas are available in the application, new ones can be added as required by users in their respective studies. Apart from the application itself, the online resources provided (website and Twitter account) significantly enhance users’ experience.

2014-01-01

32

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

33

Developmental regulation of AMPA receptor subunit expression in forebrain and relationship to regional susceptibility to hypoxic/ischemic injury: Part II. Human cerebral white matter and cortex  

PubMed Central

This report is the second of a two-part evaluation of developmental differences in ?–amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid (AMPA) receptor subunit expression in cell populations within white matter and cortex. In Part I, we report that in rat, developmental expression of Ca2+ permeable (GluR2-lacking) AMPARs correlated at the regional and cellular level with increased susceptibility to hypoxia/ischemia (H/I), suggesting an age-specific role of these receptors in the pathogenesis of brain injury. Part II examines the regional and cellular progression of AMPAR subunits in human white matter and cortex from midgestation through early childhood. Similar to the rodent, there is a direct correlation between selective vulnerability to H/I and expression of GluR2-lacking AMPARs in human brain. In midgestational cases aged 20-24 postconceptional weeks (PCW) and in premature infants (25-37 PCW), we found that radial glia, premyelinating oligodendrocytes and subplate neurons transiently expressed GluR2-lacking AMPARs. Notably, prematurity represents a developmental window of selective vulnerability for white matter injury, such as periventricular leukomalacia (PVL). During term (38-42 PCW) and post-term neonatal (43-46 PCW) periods, age windows characterized by increased susceptibility to cortical injury and seizures, GluR2 expression was low in the neocortex, specifically on cortical pyramidal and non-pyramidal neurons. This study indicates that Ca2+ permeable AMPAR blockade may represent an age-specific therapeutic strategy for potential use in humans. Furthermore, these data help validate specific rodent maturational stages as appropriate models for evaluation of H/I pathophysiology.

Talos, Delia M.; Follett, Pamela L.; Folkerth, Rebecca D.; Fishman, Rachel E.; Trachtenberg, Felicia L.; Volpe, Joseph J.; Jensen, Frances E.

2010-01-01

34

White matter abnormalities in Methcathinone abusers with an extrapyramidal syndrome  

PubMed Central

Summary We examined white matter abnormalities in patients with a distinctive extrapyramidal syndrome due to intravenous methcathinone (ephedrone) abuse. We performed diffusion tensor imaging in ten patients and fifteen age-matched controls to assess white matter structure across the whole brain. Diffuse significant decreases in white matter fractional anisotropy, a diffusion tensor imaging metric which reflects microstructural integrity, occurred in the patients compared with controls. In addition, we identified two foci of severe white matter abnormality underlying the right ventral premotor cortex and the medial frontal cortex, two cortical regions involved in higher-level executive control of motor function. Paths connecting different cortical regions with the globus pallidus, the nucleus previously shown to be abnormal on structural imaging in these patients, were generated using probabilistic tractography. The fractional anisotropy within all these tracts was lower in the patient group than controls. Finally, we tested for a relationship between white matter integrity and clinical outcome. We identified a region within the left corticospinal tract in which lower fractional anisotropy was associated with greater functional deficit but this region did not show reduced fractional anisotropy in the overall patient group compared to controls. These patients have widespread white matter damage with greatest severity of damage underlying executive motor areas.

Stepens, Ainars; Stagg, Charlotte Jane; Platkajis, Ardis; Boudrias, Marie-Helene; Johansen-Berg, Heidi; Donaghy, Michael

2013-01-01

35

Interactive effects of apolipoprotein e4 and diabetes risk on later myelinating white matter regions in neurologically healthy older aged adults.  

PubMed

Possession of the apolipoprotein E4 (APOE4) allele and diabetes risk are independently related to reduced white matter (WM) integrity that may contribute to the development of Alzheimer's disease (AD). The purpose of this study is to examine the interactive effects of APOE4 and diabetes risk on later myelinating WM regions among healthy elderly individuals at risk of AD. A sample of 107 healthy elderly (80 APOE4-/27 APOE4+) individuals underwent structural magnetic resonance imaging/diffusion tensor imaging (DTI). Data were prepared using Tract-Based Spatial Statistics, and a priori regions of interest (ROIs) were extracted from T1-based WM parcellations. Regions of interest included later myelinating frontal/temporal/parietal WM regions and control regions measured by fractional anisotropy (FA). There were no APOE group differences in DTI for any ROI. Within the APOE4 group, we found negative relationships between hemoglobin A1c/fasting glucose and APOE4 on FA for all later myelinating WM regions but not for early/middle myelinating control regions. Results also showed APOE4/diabetes risk interactions for WM underlying supramarginal, superior temporal, precuneus, superior parietal, and superior frontal regions. Results suggest interactive effects of APOE4 and diabetes risk on later myelinating WM regions, which supports preclinical detection of AD among this particularly susceptible subgroup. PMID:24381137

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

2014-05-01

36

White Matter Atlas Generation using HARDI based Automated Parcellation  

PubMed Central

Most diffusion imaging studies have used subject registration to an atlas space for enhanced quantification of anatomy. However, standard diffusion tensor atlases lack information in regions of fiber crossing and are based on adult anatomy. The degree of error associated with applying these atlases to studies of children for example has not yet been estimated but may lead to suboptimal results. This paper describes a novel technique for generating population-specific high angular resolution diffusion imaging (HARDI)-based atlases consisting of labeled regions of homogenous white matter. Our approach uses a fiber orientation distribution (FOD) diffusion model and a data driven clustering algorithm. White matter regional labeling is achieved by our automated data driven clustering algorithm that has the potential to delineate white matter regions based on fiber complexity and orientation. The advantage of such an atlas is that it is study specific and more comprehensive in describing regions of white matter homogeneity as compared to standard anatomical atlases. We have applied this state of the art technique to a dataset consisting of adolescent and preadolescent children, creating one of the first examples of a HARDI-based atlas, thereby establishing the feasibility of the atlas creation framework. The white matter regions generated by our automated clustering algorithm have lower FOD variance than when compared to the regions created from a standard anatomical atlas.

Bloy, Luke; Ingalhalikar, Madhura; Eavani, Harini; Schultz, Robert T.; Roberts, Timothy P.L.; Verma, Ragini

2011-01-01

37

White matter in learning, cognition and psychiatric disorders  

Microsoft Academic Search

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 stimu- lating research into myelin involvement in

R. Douglas Fields

2008-01-01

38

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

39

White Matter Integrity, Substance Use, and Risk Taking in Adolescence  

PubMed Central

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 non-users (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: 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.

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

2012-01-01

40

White Matter Characterization with Diffusional Kurtosis Imaging  

PubMed Central

Diffusional kurtosis imaging (DKI) is a clinically feasible extension of diffusion tensor imaging that probes restricted water diffusion in biological tissues using magnetic resonance imaging. Here we provide a physically meaningful interpretation of DKI metrics in white matter regions consisting of more or less parallel aligned fiber bundles by modeling the tissue as two non-exchanging compartments, the intra-axonal space and extra-axonal space. For the b-values typically used in DKI, the diffusion in each compartment is assumed to be anisotropic Gaussian and characterized by a diffusion tensor. The principal parameters of interest for the model include the intra- and extra-axonal diffusion tensors, the axonal water fraction and the tortuosity of the extra-axonal space. A key feature is that these can be determined directly from the diffusion metrics conventionally obtained with DKI. For three healthy young adults, the model parameters are estimated from the DKI metrics and shown to be consistent with literature values. In addition, as a partial validation of this DKI-based approach, we demonstrate good agreement between the DKI-derived axonal water fraction and the slow diffusion water fraction obtained from standard biexponential fitting to high b-value diffusion data. Combining the proposed WM model with DKI provides a convenient method for the clinical assessment of white matter in health and disease and could potentially provide important information on neurodegenerative disorders.

Fieremans, Els; Jensen, Jens H.; Helpern, Joseph A.

2011-01-01

41

Accelerated white matter aging in schizophrenia: role of white matter blood perfusion.  

PubMed

Elevated rate of age-related decline in white matter integrity, indexed by fractional anisotropy (FA) from diffusion tensor imaging, was reported in patients with schizophrenia. Its etiology is unknown. We hypothesized that a decline of blood perfusion to the white matter may underlie the accelerated age-related reduction in FA in schizophrenia. Resting white matter perfusion and FA were collected using pseudo-continuous arterial spin labeling and high-angular-resolution diffusion tensor imaging, respectively, in 50 schizophrenia patients and 70 controls (age = 18-63 years). Main outcome measures were the diagnosis-by-age interaction on whole-brain white matter perfusion, and FA. Significant age-related decline in brain white matter perfusion and FA were present in both groups. Age-by-diagnosis interaction was significant for FA (p < 0.001) but not white matter perfusion. Age-by-diagnosis interaction for FA values remained significant even after accounting for age-related decline in perfusion. Therefore, we replicated the finding of an increased rate of age-related white matter FA decline in schizophrenia and observed a significant age-related decline in white matter blood perfusion, although the latter did not contribute to the accelerated age-related decline in FA. The results suggest that factors other than reduced perfusion account for the accelerated age-related decline in white matter integrity in schizophrenia. PMID:24680326

Wright, Susan N; Kochunov, Peter; Chiappelli, Joshua; McMahon, Robert P; Muellerklein, Florian; Wijtenburg, S Andrea; White, Michael G; Rowland, Laura M; Hong, L Elliot

2014-10-01

42

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

43

White matter integrity in kleptomania: a pilot study.  

PubMed

This study's goal was to examine microstructural organization of frontal white matter in kleptomania. Ten females with DSM-IV kleptomania and 10 female controls underwent diffusion tensor imaging. Inferior frontal white matter was the a priori region of interest. Trace and fractional anisotropy (FA) were also calculated for frontal and posterior cortical regions in both subject groups. Kleptomania subjects had significantly higher mean frontal Trace, and significantly lower mean frontal FA than control subjects. Group differences remained significant when right and left frontal Trace and FA were analyzed. Groups did not differ significantly in posterior Trace or FA. Kleptomania may be associated with decreased white matter microstructural integrity in inferior frontal brain regions. PMID:16956753

Grant, Jon E; Correia, Stephen; Brennan-Krohn, Thea

2006-10-30

44

Profiles of white matter tract pathology in frontotemporal dementia.  

PubMed

Despite considerable interest in improving clinical and neurobiological characterisation of frontotemporal dementia and in defining the role of brain network disintegration in its pathogenesis, information about white matter pathway alterations in frontotemporal dementia remains limited. Here we investigated white matter tract damage using an unbiased, template-based diffusion tensor imaging (DTI) protocol in a cohort of 27 patients with the behavioral variant of frontotemporal dementia (bvFTD) representing both major genetic and sporadic forms, in relation both to healthy individuals and to patients with Alzheimer's disease. Widespread white matter tract pathology was identified in the bvFTD group compared with both healthy controls and Alzheimer's disease group, with prominent involvement of uncinate fasciculus, cingulum bundle and corpus callosum. Relatively discrete and distinctive white matter profiles were associated with genetic subgroups of bvFTD associated with MAPT and C9ORF72 mutations. Comparing diffusivity metrics, optimal overall separation of the bvFTD group from the healthy control group was signalled using radial diffusivity, whereas optimal overall separation of the bvFTD group from the Alzheimer's disease group was signalled using fractional anisotropy. Comparing white matter changes with regional grey matter atrophy (delineated using voxel based morphometry) in the bvFTD cohort revealed co-localisation between modalities particularly in the anterior temporal lobe, however white matter changes extended widely beyond the zones of grey matter atrophy. Our findings demonstrate a distributed signature of white matter alterations that is likely to be core to the pathophysiology of bvFTD and further suggest that this signature is modulated by underlying molecular pathologies. Hum Brain Mapp 35:4163-4179, 2014. © 2014 The Authors. Human Brain Mapping Published by Wiley Periodicals, Inc. PMID:24510641

Mahoney, Colin J; Ridgway, Gerard R; Malone, Ian B; Downey, Laura E; Beck, Jonathan; Kinnunen, Kirsi M; Schmitz, Nicole; Golden, Hannah L; Rohrer, Jonathan D; Schott, Jonathan M; Rossor, Martin N; Ourselin, Sebastien; Mead, Simon; Fox, Nick C; Warren, Jason D

2014-08-01

45

White matter development during adolescence as shown by diffusion MRI.  

PubMed

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 fractional anisotropy (FA) with age and decreasing mean diffusivity (MD) with age, findings primarily due to decreasing radial diffusivity with age. However, results of studies vary as to the regional specificity of such age-related changes, likely due in part to methodological issues. Another general trend is for FA to positively correlate and MD to negatively correlate with cognitive function. This trend is however region-specific, task-specific, and population-specific; some studies have in fact found negative correlations of FA and positive correlations of MD in specific regions with specific measures of cognitive performance. There are also published reports of sexual dimorphism in white matter development, indicating differing developmental trajectories between males and females as well as differing relationships developmentally between white matter architecture and cognitive function. There is a need for more research to further elucidate the development of white matter and its relation to cognitive function during this critical developmental period. PMID:19628324

Schmithorst, Vincent J; Yuan, Weihong

2010-02-01

46

White Matter Heritability Using Diffusion Tensor Imaging in Neonatal Brains  

PubMed Central

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.

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

2012-01-01

47

A voxel-based morphometry (VBM) analysis of regional grey and white matter volume abnormalities within the speech production network of children who stutter.  

PubMed

It is well documented that neuroanatomical differences exist between adults who stutter and their fluently speaking peers. Specifically, adults who stutter have been found to have more grey matter volume (GMV) in speech relevant regions including inferior frontal gyrus, insula and superior temporal gyrus (Beal et al., 2007; Song et al., 2007). Despite stuttering having its onset in childhood only one study has investigated the neuroanatomical differences between children who do and do not stutter. Chang et al. (2008) reported children who stutter had less GMV in the bilateral inferior frontal gyri and middle temporal gyrus relative to fluently speaking children. Thus it appears that children who stutter present with unique neuroanatomical abnormalities as compared to those of adults who stutter. In order to better understand the neuroanatomical correlates of stuttering earlier in its development, near the time of onset, we used voxel-based morphometry to examine volumetric differences between 11 children who stutter and 11 fluent children. Children who stutter had less GMV in the bilateral inferior frontal gyri and left putamen but more GMV in right Rolandic operculum and superior temporal gyrus relative to fluent children. Children who stutter also had less white matter volume bilaterally in the forceps minor of the corpus callosum. We discuss our findings of widespread anatomic abnormalities throughout the cortical network for speech motor control within the context of the speech motor skill limitations identified in people who stutter (Namasivayam and van Lieshout, 2008; Smits-Bandstra et al., 2006). PMID:23140891

Beal, Deryk S; Gracco, Vincent L; Brettschneider, Jane; Kroll, Robert M; De Nil, Luc F

2013-09-01

48

Impaired empathic abilities and reduced white matter integrity in schizophrenia.  

PubMed

Empathic abilities are impaired in schizophrenia. Although the pathology of schizophrenia is thought to involve disrupted white matter integrity, the relationship between empathic disabilities and altered white matter in the disorder remains unclear. The present study tested associations between empathic disabilities and white matter integrity in order to investigate the neural basis of impaired empathy in schizophrenia. Sixty-nine patients with schizophrenia and 69 age-, gender-, handedness-, education- and IQ level-matched healthy controls underwent diffusion-weighted imaging. Empathic abilities were assessed using the Interpersonal Reactivity Index (IRI). Using tract-based spatial statistics (TBSS), the associations between empathic abilities and white matter fractional anisotropy (FA), a measure of white matter integrity, were examined in the patient group within brain areas that showed a significant FA reduction compared with the controls. The patients with schizophrenia reported lower perspective taking and higher personal distress according to the IRI. The patients showed a significant FA reduction in bilateral deep white matter in the frontal, temporal, parietal and occipital lobes, a large portion of the corpus callosum, and the corona radiata. In schizophrenia patients, fantasy subscales positively correlated with FA in the left inferior fronto-occipital fasciculi and anterior thalamic radiation, and personal distress subscales negatively correlated with FA in the splenium of the corpus callosum. These results suggest that disrupted white matter integrity in these regions constitutes a pathology underpinning specific components of empathic disabilities in schizophrenia, highlighting that different aspects of empathic impairments in the disorder would have, at least partially, distinct neuropathological bases. PMID:24099786

Fujino, Junya; Takahashi, Hidehiko; Miyata, Jun; Sugihara, Genichi; Kubota, Manabu; Sasamoto, Akihiko; Fujiwara, Hironobu; Aso, Toshihiko; Fukuyama, Hidenao; Murai, Toshiya

2014-01-01

49

Associations Between White Matter Microstructure and Infants' Working Memory  

PubMed Central

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.

Short, Sarah J.; Elison, Jed T.; Goldman, Barbara Davis; Styner, Martin; Gu, Hongbin; Connelly, Mark; Maltbie, Eric; Woolson, Sandra; Lin, Weili; Gerig, Guido; Reznick, J. Steven; Gilmore, John H.

2013-01-01

50

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

51

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

52

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

53

Diffusion tensor sharpening improves white matter tractography  

NASA Astrophysics Data System (ADS)

Diffusion Tensor Imaging (DTI) is currently a widespread technique to infer white matter architecture in the human brain. An important application of DTI is to understand the anatomical coupling between functional cortical regions of the brain. To solve this problem, anisotropy maps are insufficient and fiber tracking methods are used to obtain the main fibers. While the diffusion tensor (DT) is important to obtain anisotropy maps and apparent diffusivity of the underlying tissue, fiber tractography using the full DT may result in diffusive tracking that leaks into unexpected regions. Sharpening is thus of utmost importance to obtain complete and accurate tracts. In the tracking literature, only heuristic methods have been proposed to deal with this problem. We propose a new tensor sharpening transform. Analogously to the general issue with the diffusion and fiberOrientation Distribution Function (ODF) encountered when working with High Angular Resolution Diffusion Imaging (HARDI), we show how to transform the diffusion tensors into so-called fiber tensors. We demonstrate that this tensor transform is a natural pre-processing task when one is interested in fiber tracking. It also leads to a dramatic improvement of the tractography results obtained by front propagation techniques on the full diffusion tensor. We compare and validate sharpening and tracking results on synthetic data and on known fiber bundles in the human brain.

Descoteaux, Maxime; Lenglet, Christophe; Deriche, Rachid

2007-03-01

54

Gestational iron deficiency differentially alters the structure and function of white and gray matter brain regions of developing rats.  

PubMed

Gestational iron deficiency (ID) has been associated with a wide variety of central nervous system (CNS) impairments in developing offspring. However, a focus on singular regions has impeded an understanding of the CNS-wide effects of this micronutrient deficiency. Because the developing brain requires iron during specific phases of growth in a region-specific manner, we hypothesized that maternal iron deprivation would lead to region-specific impairments in the CNS of offspring. Female rats were fed an iron control (Fe+) or iron-deficient (Fe-) diet containing 240 or 6 ?g/g iron during gestation and lactation. The corpus callosum (CC), hippocampus, and cortex of the offspring were analyzed at postnatal day 21 (P21) and/or P40 using structural and functional measures. In the CC at P40, ID was associated with reduced peak amplitudes of compound action potentials specific to myelinated axons, in which diameters were reduced by ?20% compared with Fe+ controls. In the hippocampus, ID was associated with a 25% reduction in basal dendritic length of pyramidal neurons at P21, whereas branching complexity was unaffected. We also identified a shift toward increased proximal branching of apical dendrites in ID without an effect on overall length compared with Fe+ controls. ID also affected cortical neurons, but unlike the hippocampus, both apical and basal dendrites displayed a uniform decrease in branching complexity, with no significant effect on overall length. These deficits culminated in significantly poorer performance of P40 Fe- offspring in the novel object recognition task. Collectively, these results demonstrate that non-anemic gestational ID has a significant and region-specific impact on neuronal development and may provide a framework for understanding and recognizing the presentation of clinical symptoms of ID. PMID:24744313

Greminger, Allison R; Lee, Dawn L; Shrager, Peter; Mayer-Pröschel, Margot

2014-07-01

55

Long-Term Vision and Non-Vision Dominant Behavioral Deficits in the 2-VO Rats Are Accompanied by Time and Regional Glial Activation in the White Matter  

PubMed Central

The permanent occlusion of common carotid arteries (2-VO) in rats has been shown to induce progressive and long-lasting deficits in cognitive performance, however, whether these aberrant behaviors are attributed to visual dysfunction or cognitive impairment and what are the underlying mechanisms, remain controversial. In the present study, vision dominant (Morris water maze) and non-vision dominant (voice-cued fear conditioning) behavioral tests were assigned to comprehensively evaluate the influence of 2-VO lesion on cognitive behaviors. In the Morris water maze test, escape latencies of 2-VO rats were markedly increased in both hidden and unfixed visible platform tasks, which were accompanied by severe retinal damage. In the voice-cued fear conditioning test, significant reduction in the percentage of freezing behavior was observed at 60 days after 2-VO lesion. Chronic lesion by 2-VO failed to cause noticeable changes in the grey matter, as indicated by intact hippocampal and prefrontal cortical structures, sustained synaptic protein levels and glial cell numbers. In contrast, aberrant arrangement of myelinated axons was observed in the optic tract, but not in the corpus callosum and inner capsule of 2-VO rats. Concurrently, marked astrocyte proliferation and microglia activation in the optic tract occurred at 3 days after 2-VO lesion, and continued for up to 60 days. Differently, robust glial activation was observed in the corpus callosum at 3 days after 2-VO surgery, and then gradually returned to the baseline level at 14 and 60 days. Our study reported for the first time about the effect of 2-VO on the long-term cognitive impairment in the non-vision dominant fear conditioning test, which may be more applicable than the Morris water maze test for assessing 2-VO associated cognitive function. The time and region specific glial activation in the white matter may relate to retinal impairment, even behavioral deficits, in the setting of chronic cerebral hypoperfusion.

Ruan, Zhi; Lei, Yun; Chen, Yu Ting; Zhang, Hai Yan

2014-01-01

56

Long-Term Vision and Non-Vision Dominant Behavioral Deficits in the 2-VO Rats Are Accompanied by Time and Regional Glial Activation in the White Matter.  

PubMed

The permanent occlusion of common carotid arteries (2-VO) in rats has been shown to induce progressive and long-lasting deficits in cognitive performance, however, whether these aberrant behaviors are attributed to visual dysfunction or cognitive impairment and what are the underlying mechanisms, remain controversial. In the present study, vision dominant (Morris water maze) and non-vision dominant (voice-cued fear conditioning) behavioral tests were assigned to comprehensively evaluate the influence of 2-VO lesion on cognitive behaviors. In the Morris water maze test, escape latencies of 2-VO rats were markedly increased in both hidden and unfixed visible platform tasks, which were accompanied by severe retinal damage. In the voice-cued fear conditioning test, significant reduction in the percentage of freezing behavior was observed at 60 days after 2-VO lesion. Chronic lesion by 2-VO failed to cause noticeable changes in the grey matter, as indicated by intact hippocampal and prefrontal cortical structures, sustained synaptic protein levels and glial cell numbers. In contrast, aberrant arrangement of myelinated axons was observed in the optic tract, but not in the corpus callosum and inner capsule of 2-VO rats. Concurrently, marked astrocyte proliferation and microglia activation in the optic tract occurred at 3 days after 2-VO lesion, and continued for up to 60 days. Differently, robust glial activation was observed in the corpus callosum at 3 days after 2-VO surgery, and then gradually returned to the baseline level at 14 and 60 days. Our study reported for the first time about the effect of 2-VO on the long-term cognitive impairment in the non-vision dominant fear conditioning test, which may be more applicable than the Morris water maze test for assessing 2-VO associated cognitive function. The time and region specific glial activation in the white matter may relate to retinal impairment, even behavioral deficits, in the setting of chronic cerebral hypoperfusion. PMID:24968196

Tian, Xue Song; Guo, Xian Jun; Ruan, Zhi; Lei, Yun; Chen, Yu Ting; Zhang, Hai Yan

2014-01-01

57

Structural neuroimaging in Alzheimer's disease: do white matter hyperintensities matter?  

PubMed Central

The targeted brain dysfunction that accompanies aging can have a devastating effect on cognitive and intellectual abilities. A significant proportion of older adults experience precipitous cognitive decline that negatively impacts functional activities. Such individuals meet clinical diagnostic criteria for dementia, which is commonly attributed to Alzheimer's disease (AD). Structural neuroimaging, including magnetic resonance imaging (MRI), has contributed significantly to our understanding of the morphological and pathology-related changes that may underlie normal and disease-associated cognitive change in aging. White matter hyperintensities (WMH), which are distributed patches of increased hyperintense signal on T2-weighted MRI, are among the most common structural neuroimaging findings in older adults. In recent years, WMH have emerged as robust radiological correlates of cognitive decline. Studies suggest that WMH distributed in anterior brain regions are related to decline in executive abilities that is typical of normal aging, whereas WMH distributed in more posterior brain regions are common in AD. Although epidemiological, observational, and pathological studies suggest that WMH may be ischemic in origin and caused by consistent or variable hypoperfusion, there is emerging evidence that they may also reflect vascular deposition of (?-amyloid, particularly when they are distributed in posterior areas and are present in patients with AD. Findings from the literature highlight the potential contribution of small-vessel cerebrovascular disease to the pathogenesis of AD, and suggest a mechanistic interaction, but future longitudinal studies using multiple imaging modalities are required to fully understand the complex role of WMH in AD.

Brickman, Adam M.; Muraskin, Jordan; Zimmerman, Molly E.

2009-01-01

58

White matter development and early cognition in babies and toddlers.  

PubMed

The normal myelination of neuronal axons is essential to neurodevelopment, allowing fast inter-neuronal communication. The most dynamic period of myelination occurs in the first few years of life, in concert with a dramatic increase in cognitive abilities. How these processes relate, however, is still unclear. Here we aimed to use a data-driven technique to parcellate developing white matter into regions with consistent white matter growth trajectories and investigate how these regions related to cognitive development. In a large sample of 183 children aged 3 months to 4 years, we calculated whole brain myelin volume fraction (VFM ) maps using quantitative multicomponent relaxometry. We used spatial independent component analysis (ICA) to blindly segment these quantitative VFM images into anatomically meaningful parcels with distinct developmental trajectories. We further investigated the relationship of these trajectories with standardized cognitive scores in the same children. The resulting components represented a mix of unilateral and bilateral white matter regions (e.g., cortico-spinal tract, genu and splenium of the corpus callosum, white matter underlying the inferior frontal gyrus) as well as structured noise (misregistration, image artifact). The trajectories of these regions were associated with individual differences in cognitive abilities. Specifically, components in white matter underlying frontal and temporal cortices showed significant relationships to expressive and receptive language abilities. Many of these relationships had a significant interaction with age, with VFM becoming more strongly associated with language skills with age. These data provide evidence for a changing coupling between developing myelin and cognitive development. Hum Brain Mapp 35:4475-4487, 2014. © 2014 The Authors. Human Brain Mapping Published by Wiley Periodicals, Inc. PMID:24578096

O'Muircheartaigh, Jonathan; Dean, Douglas C; Ginestet, Cedric E; Walker, Lindsay; Waskiewicz, Nicole; Lehman, Katie; Dirks, Holly; Piryatinsky, Irene; Deoni, Sean C L

2014-09-01

59

Origins of R2? and white matter  

PubMed Central

Estimates of the apparent transverse relaxation rate () can be used to quantify important properties of biological tissue. Surprisingly, the mechanism of dependence on tissue orientation is not well understood. The primary goal of this paper was to characterize orientation dependence of in gray and white matter and relate it to independent measurements of two other susceptibility based parameters: the local Larmor frequency shift (fL) and quantitative volume magnetic susceptibility (??). Through this comparative analysis we calculated scaling relations quantifying (reversible contribution to the transverse relaxation rate from local field inhomogeneities) in a voxel given measurements of the local Larmor frequency shift. is a measure of both perturber geometry and density and is related to tissue microstructure. Additionally, two methods (the Generalized Lorentzian model and iterative dipole inversion) for calculating ?? were compared in gray and white matter. The value of ?? derived from fitting the Generalized Lorentzian model was then connected to the observed orientation dependence using image-registered optical density measurements from histochemical staining. Our results demonstrate that the and fL of white and cortical gray matter are well described by a sinusoidal dependence on the orientation of the tissue and a linear dependence on the volume fraction of myelin in the tissue. In deep brain gray matter structures, where there is no obvious symmetry axis, and fL have no orientation dependence but retain a linear dependence on tissue iron concentration and hence ??.

Rudko, David A.; Klassen, L. Martyn; de Chickera, Sonali N.; Gati, Joseph S.; Dekaban, Gregory A.; Menon, Ravi S.

2014-01-01

60

White matter microstructure correlates of mathematical giftedness and intelligence quotient.  

PubMed

Recent functional neuroimaging studies have shown differences in brain activation between mathematically gifted adolescents and controls. The aim of this study was to investigate the relationship between mathematical giftedness, intelligent quotient (IQ), and the microstructure of white matter tracts in a sample composed of math-gifted adolescents and aged-matched controls. Math-gifted subjects were selected through a national program based on detecting enhanced visuospatial abilities and creative thinking. We used diffusion tensor imaging to assess white matter microstructure in neuroanatomical connectivity. The processing included voxel-wise and region of interest-based analyses of the fractional anisotropy (FA), a parameter which is purportedly related to white matter microstructure. In a whole-sample analysis, IQ showed a significant positive correlation with FA, mainly in the corpus callosum, supporting the idea that efficient information transfer between hemispheres is crucial for higher intellectual capabilities. In addition, math-gifted adolescents showed increased FA (adjusted for IQ) in white matter tracts connecting frontal lobes with basal ganglia and parietal regions. The enhanced anatomical connectivity observed in the forceps minor and splenium may underlie the greater fluid reasoning, visuospatial working memory, and creative capabilities of these children. Hum Brain Mapp 35:2619-2631, 2014. © 2013 Wiley Periodicals, Inc. PMID:24038774

Navas-Sánchez, Francisco J; Alemán-Gómez, Yasser; Sánchez-Gonzalez, Javier; Guzmán-De-Villoria, Juan A; Franco, Carolina; Robles, Olalla; Arango, Celso; Desco, Manuel

2014-06-01

61

An autopsy case of infantile-onset vanishing white matter disease related to an EIF2B2 mutation (V85E) in a hemizygous region  

PubMed Central

We report a rare autopsy case of early infantile-onset vanishing white matter disease, with a submicroscopic deletion of 14q24.3, which included EIF2B2 and a missense mutation of EIF2B2 (V85E) of the remaining allele. The patient was a 4-year-old boy, who was found to have suddenly died during sleep. Physical and mental development began to deteriorate after convulsions at 10 month of age, and did not recover to baseline measurements. At autopsy, the brain showed a marked decrease in volume of white matter, with no typical cystic rarefaction. Histopathologically, the affected white matter showed diffuse loss of myelin fibers, meager astrogliosis with dysmorphic astrocytes, and loss of oligodendrocytes. Proliferative and apoptotic markers were negative for oligodendrocytes in the severely affected area. These findings may be related to the severity of the disease, and might be a feature of the EIF2B2 mutation pattern of the patient. Additionally, unusual fatty infiltration of both ventricles of the heart was found. These findings were suspected as early pathology of arrhythmogenic right ventricular cardiomyopathy due to characteristic gene mutation in the present case. In the present case, the defect EIF2B2 caused by hemizygosity may be related to early onset of the disease and the unusual pathological changes with vulnerability of oligodendrocytes and astrocytes, as well as cardiac abnormalities and sudden unexpected death.

Hata, Yukiko; Kinoshita, Koshi; Miya, Kazushi; Hirono, Keiichi; Ichida, Fukiko; Yoshida, Koji; Nishida, Naoki

2014-01-01

62

DTI white matter fiber tractography using bayesian framework  

Microsoft Academic Search

Diffusion tensor-MRI (DTI) White matter fiber tracking traces white matter fibber bundle and its image according to the diffusion of water molecular in the white matter. This paper uses structure information of fiber bundle and DTI information in current voxel to estimate the probability density function of the tracking direction to the next voxel. This algorithm is under the framework

Xi Wu

2010-01-01

63

A Bayesian approach for stochastic white matter tractography  

Microsoft Academic Search

White matter fiber bundles in the human brain can be located by tracing the local water diffusion in diffusion weighted magnetic resonance imaging (MRI) images. In this paper, a novel Bayesian modeling approach for white matter tractography is pre- sented. The uncertainty associated with estimated white matter fiber paths is investigated, and a method for calculating the proba- bility of

Ola Friman; Gunnar Farnebäck; Carl-fredrik Westin

2006-01-01

64

Diffusion Tensor Imaging of Cerebral White Matter  

Microsoft Academic Search

\\u000a Abstract\\u000a   Diffusion tensor imaging (DTI) of the cerebral white matter has proven to be a promising tool with regard to demonstration\\u000a of developmental changes during childhood and older age and of pathologic alterations by calculation of parameter maps of\\u000a mean diffusivity (MD) and fractional anisotropy (FA) as well as to image the positions of the major fiber tracts by tractography.

Peter Stoeter; Paulo Roberto Dellani; Goran Vucurevic

2008-01-01

65

Emerging concepts in periventricular white matter injury.  

PubMed

Approximately 10% of newborns are born prematurely. Of these children, more than 10% will sustain neurological injuries leading to significant learning disabilities, cerebral palsy, or mental retardation, with very low birth weight infants having an even higher incidence of brain injury. Whereas intraventricular hemorrhage was the most common form of serious neurological injury a decade ago, periventricular white matter injury (PWMI) is now the most common cause of brain injury in preterm infants. The spectrum of chronic PWMI includes focal cystic necrotic lesions (periventricular leukomalacia; PVL) and diffuse myelination disturbances. Recent neuroimaging studies support that the incidence of PVL is declining, whereas diffuse cerebral white matter injury is emerging as the predominant lesion. Factors that predispose to PVL include prematurity, hypoxia, ischemia, and inflammation. It is believed that injury to oligodendrocyte (OL) progenitors contributes to the pathogenesis of myelination disturbances in PWMI by disrupting the maturation of myelin-myelin-forming oligodendrocytes. Other potential mechanisms of injury include activation of microglia and axonal damage. Chemical mediators that may contribute to white matter injury include reactive oxygen (ROS) and nitrogen species (RNS), glutamate, cytokines, and adenosine. As our understanding of the pathogenesis of PWMI improves, it is anticipated that new strategies for directly preventing brain injury in premature infants will evolve. PMID:15693397

Back, Stephen A; Rivkees, Scott A

2004-12-01

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

2013-10-01

67

Late life cognitive control deficits are accentuated by white matter disease burden  

PubMed Central

Recent evidence suggests that age-related impairments in cognition may be mediated by a specific deficit in the ability to maintain goal-relevant information, a critical component of cognitive control dependent on the dorsolateral prefrontal cortex, although the underlying neural mechanism of these deficits remains unclear. To examine white matter hyperintensities as a neurobiological mechanism of these impairments, older individuals with severe white matter hyperintensity burden, older individuals with low white matter hyperintensity burden, and young adults were assessed in an event-related functional imaging scan while performing the ‘AX’-continuous performance task. Individuals with severe white matter hyperintensity burden showed a significant reduction in dorsolateral prefrontal cortex activity during the high cognitive control cue condition relative to the low white matter hyperintensity group and young individuals. Conversely, those with severe white matter hyperintensity burden showed greater activity in rostral anterior cingulate cortex compared to young individuals. These results are consistent with impaired cognitive control and a possible failure to deactivate default-mode regions in these subjects. Additionally, those with severe white matter hyperintensity burden showed reduced functional connectivity between dorsolateral prefrontal cortex and task-relevant brain regions including middle frontal gyrus, and supramarginal gyrus relative to young subjects and those with minimal white matter hyperintensity burden. These results suggest that age-related goal maintenance impairments and associated dorsolateral prefrontal cortex dysfunction may partly reflect incipient white matter disease of interconnected cognitive networks.

Mayda, Adriane B. V.; Westphal, Andrew; Carter, Cameron S.

2011-01-01

68

Pediatric neurodegenerative white matter processes: leukodystrophies and beyond  

Microsoft Academic Search

Pediatric neurodegenerative white matter processes are complex, numerous and result from a vast array of causes ranging from\\u000a white matter injury or inflammation to congenital metabolic disorders. When faced with a neurodegenerative white matter process\\u000a on neuroimaging, the first step for the radiologist is to determine whether the findings represent a congenital metabolic\\u000a leukodystrophy or one of various other white

Jonathan A. Phelan; Lisa H. Lowe; Charles M. Glasier

2008-01-01

69

White Matter Maturation Supports the Development of Reasoning Ability through Its Influence on Processing Speed  

ERIC Educational Resources Information Center

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…

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

2013-01-01

70

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

2013-08-01

71

Diffusion Features of White Matter in Tuberous Sclerosis With Tractography  

PubMed Central

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.

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

2010-01-01

72

Imaging White Matter in Human Brainstem  

PubMed Central

The human brainstem is critical for the control of many life-sustaining functions, such as consciousness, respiration, sleep, and transfer of sensory and motor information between the brain and the spinal cord. Most of our knowledge about structure and organization of white and gray matter within the brainstem is derived from ex vivo dissection and histology studies. However, these methods cannot be applied to study structural architecture in live human participants. Tractography from diffusion-weighted magnetic resonance imaging (MRI) may provide valuable insights about white matter organization within the brainstem in vivo. However, this method presents technical challenges in vivo due to susceptibility artifacts, functionally dense anatomy, as well as pulsatile and respiratory motion. To investigate the limits of MR tractography, we present results from high angular resolution diffusion imaging of an intact excised human brainstem performed at 11.1?T using isotropic resolution of 0.333, 1, and 2?mm, with the latter reflecting resolution currently used clinically. At the highest resolution, the dense fiber architecture of the brainstem is evident, but the definition of structures degrades as resolution decreases. In particular, the inferred corticopontine/corticospinal tracts (CPT/CST), superior (SCP) and middle cerebellar peduncle (MCP), and medial lemniscus (ML) pathways are clearly discernable and follow known anatomical trajectories at the highest spatial resolution. At lower resolutions, the CST/CPT, SCP, and MCP pathways are artificially enlarged due to inclusion of collinear and crossing fibers not inherent to these three pathways. The inferred ML pathways appear smaller at lower resolutions, indicating insufficient spatial information to successfully resolve smaller fiber pathways. Our results suggest that white matter tractography maps derived from the excised brainstem can be used to guide the study of the brainstem architecture using diffusion MRI in vivo.

Ford, Anastasia A.; Colon-Perez, Luis; Triplett, William T.; Gullett, Joseph M.; Mareci, Thomas H.; FitzGerald, David B.

2013-01-01

73

Age-Related White Matter Changes  

PubMed Central

Age-related white matter changes (WMC) are considered manifestation of arteriolosclerotic small vessel disease and are related to age and vascular risk factors. Most recent studies have shown that WMC are associated with a host of poor outcomes, including cognitive impairment, dementia, urinary incontinence, gait disturbances, depression, and increased risk of stroke and death. Although the clinical relevance of WMC has been extensively studied, to date, only very few clinical trials have evaluated potential symptomatic or preventive treatments for WMC. In this paper, we reviewed the current understanding in the pathophysiology, epidemiology, clinical importance, chemical biomarkers, and treatments of age-related WMC.

Xiong, Yun Yun; Mok, Vincent

2011-01-01

74

Structural gray and white matter changes in patients with HIV.  

PubMed

In this cross-sectional study we used magnetic resonance imaging (MRI)-based voxel based morphometry (VBM) in a sample of HIV positive patients to detect structural gray and white matter changes. Forty-eight HIV positive subjects with (n = 28) or without (n = 20) cognitive deficits (mean age 48.5 ± 9.6 years) and 48 age- and sex-matched HIV negative controls underwent MRI for VBM analyses. Clinical testing in HIV patients included the HIV dementia scale (HDS), Unified Parkinson's Disease Rating Scale (UPDRS) and the grooved pegboard test. Comparing controls with HIV positive patients with cognitive dysfunction (n = 28) VBM showed gray matter decrease in the anterior cingulate and temporal cortices along with white matter reduction in the midbrain region. These changes were more prominent with increasing cognitive decline, when assigning HIV patients to three cognitive groups (not impaired, mildly impaired, overtly impaired) based on performance in the HIV dementia scale. Regression analysis including all HIV positive patients with available data revealed that prefrontal gray matter atrophy in HIV was associated with longer disease duration (n = 48), while motor dysfunction (n = 48) was associated with basal ganglia gray matter atrophy. Lower CD4 cell count (n = 47) correlated with decrease of occipital gray matter. Our results provide evidence for atrophy of nigro-striatal and fronto-striatal circuits in HIV. This pattern of atrophy is consistent with motor dysfunction and dysexecutive syndrome found in HIV patients with HIV-associated neurocognitive disorder. PMID:21207051

Küper, Michael; Rabe, K; Esser, S; Gizewski, E R; Husstedt, I W; Maschke, M; Obermann, M

2011-06-01

75

MRI-detected white matter lesions: do they really matter?  

PubMed

Despite extensive research over the last decades the clinical significance of white matter lesions (WMLs) is still a matter of debate. Here, we review current knowledge of the correlation between WMLs and cognitive functioning as well as their predictive value for future stroke, dementia, and functional decline in activities of daily living. There is clear evidence that age-related WMLs relate to all of these outcomes on a group level, but the inter-individual variability is high. The association between WMLs and clinical phenotypes exists particularly for early confluent to confluent changes, which are ischaemic in aetiology and progress quickly over time. One reason for the variability of the relationship between WMLs and clinic on an individual level is probably the complexity of the association. Numerous factors such as cognitive reserve, concomitant loss of brain volume, and ultrastructural changes have been identified as mediators between white matter damage and clinical findings, and need to be incorporated in the consideration of WMLs as visible markers of these detrimental processes. PMID:21340713

Schmidt, Reinhold; Grazer, Anja; Enzinger, Christian; Ropele, Stefan; Homayoon, Nina; Pluta-Fuerst, Aga; Schwingenschuh, Petra; Katschnig, Petra; Cavalieri, Margherita; Schmidt, Helena; Langkammer, Christian; Ebner, Franz; Fazekas, Franz

2011-05-01

76

Whole-brain voxel-based statistical analysis of gray matter and white matter in temporal lobe epilepsy  

Microsoft Academic Search

Volumetric MRI studies based on manual labeling of selected anatomical structures have provided in vivo evidence that brain abnormalities associated with temporal lobe epilepsy (TLE) extend beyond the hippocampus. Voxel-based morphometry (VBM) is a fully automated image analysis technique allowing identification of regional differences in gray matter (GM) and white matter (WM) between groups of subjects without a prior region

N. Bernasconi; S. Duchesne; A. Janke; J. Lerch; D. L. Collins; A. Bernasconi

2004-01-01

77

Evaluation of white matter myelin water fraction in chronic stroke.  

PubMed

Multi-component T2 relaxation imaging (MCRI) provides specific in vivo measurement of myelin water content and tissue water environments through myelin water fraction (MWF), intra/extra-cellular water fraction (I/EWF) and intra/extracellular and global geometric mean T2 (GMT2) times. Quantitative MCRI assessment of tissue water environments has provided new insights into the progression and underlying white matter pathology in neural disorders such as multiple sclerosis. It has not previously been applied to investigate changes in white matter in the stroke-affected brain. Thus, the purposes of this study were to 1) use MCRI to index myelin water content and tissue water environments in the brain after stroke 2) evaluate relationships between MWF and diffusion behavior indexed by diffusion tensor imaging-based metrics and 3) examine the relationship between white matter status (MWF and fractional anisotropy) and motor behavior in the chronic phase of stroke recovery. Twenty individuals with ischemic stroke and 12 matched healthy controls participated. Excellent to good test/re-test and inter-rater reliability was observed for region of interest-based voxelwise MWF data. Reduced MWF was observed in whole-cerebrum white matter (p < 0.001) and in the ipsilesional (p = 0.017) and contralesional (p = 0.037) posterior limb of internal capsule (PLIC) after stroke compared to whole-cerebrum and bilateral PLIC MWF in healthy controls. The stroke group also demonstrated increased I/EWF, I/E GMT2 and global GMT2 times for whole-cerebrum white matter. Measures of diffusion behavior were also significantly different in the stroke group across each region investigated (p < 0.001). MWF was not significantly correlated with specific tensor-based measures of diffusion in the PLIC for either group. Fractional anisotropy in the ipsilesional PLIC correlated with motor behavior in chronic stroke. These results provide novel insights into tissue-specific changes within white matter after stroke that may have important applications for the understanding of the neuropathology of stroke. PMID:24179808

Borich, M R; Mackay, A L; Vavasour, I M; Rauscher, A; Boyd, L A

2013-01-01

78

Evaluation of white matter myelin water fraction in chronic stroke?  

PubMed Central

Multi-component T2 relaxation imaging (MCRI) provides specific in vivo measurement of myelin water content and tissue water environments through myelin water fraction (MWF), intra/extra-cellular water fraction (I/EWF) and intra/extracellular and global geometric mean T2 (GMT2) times. Quantitative MCRI assessment of tissue water environments has provided new insights into the progression and underlying white matter pathology in neural disorders such as multiple sclerosis. It has not previously been applied to investigate changes in white matter in the stroke-affected brain. Thus, the purposes of this study were to 1) use MCRI to index myelin water content and tissue water environments in the brain after stroke 2) evaluate relationships between MWF and diffusion behavior indexed by diffusion tensor imaging-based metrics and 3) examine the relationship between white matter status (MWF and fractional anisotropy) and motor behavior in the chronic phase of stroke recovery. Twenty individuals with ischemic stroke and 12 matched healthy controls participated. Excellent to good test/re-test and inter-rater reliability was observed for region of interest-based voxelwise MWF data. Reduced MWF was observed in whole-cerebrum white matter (p < 0.001) and in the ipsilesional (p = 0.017) and contralesional (p = 0.037) posterior limb of internal capsule (PLIC) after stroke compared to whole-cerebrum and bilateral PLIC MWF in healthy controls. The stroke group also demonstrated increased I/EWF, I/E GMT2 and global GMT2 times for whole-cerebrum white matter. Measures of diffusion behavior were also significantly different in the stroke group across each region investigated (p < 0.001). MWF was not significantly correlated with specific tensor-based measures of diffusion in the PLIC for either group. Fractional anisotropy in the ipsilesional PLIC correlated with motor behavior in chronic stroke. These results provide novel insights into tissue-specific changes within white matter after stroke that may have important applications for the understanding of the neuropathology of stroke.

Borich, M.R.; MacKay, A.L.; Vavasour, I.M.; Rauscher, A.; Boyd, L.A.

2013-01-01

79

Aging in deep gray matter and white matter revealed by diffusional kurtosis imaging.  

PubMed

Diffusion tensor imaging has already been extensively used to probe microstructural alterations in white matter tracts, and scarcely, in deep gray matter. However, results in literature regarding age-related degenerative mechanisms in white matter tracts and parametric changes in the putamen are inconsistent. Diffusional kurtosis imaging is a mathematical extension of diffusion tensor imaging, which could more comprehensively mirror microstructure, particularly in isotropic tissues such as gray matter. In this study, we used the diffusional kurtosis imaging method and a white-matter model that provided metrics of explicit neurobiological interpretations in healthy participants (58 in total, aged from 25 to 84 years). Tract-based whole-brain analyses and regions-of-interest (anterior and posterior limbs of the internal capsule, cerebral peduncle, fornix, genu and splenium of corpus callosum, globus pallidus, substantia nigra, red nucleus, putamen, caudate nucleus, and thalamus) analyses were performed to examine parametric differences across regions and correlations with age. In white matter tracts, evidence was found supportive for anterior-posterior gradient and not completely supportive for retrogenesis theory. Age-related degenerations appeared to be broadly driven by axonal loss. Demyelination may also be a major driving mechanism, although confined to the anterior brain. In terms of deep gray matter, higher mean kurtosis and fractional anisotropy in the globus pallidus, substantia nigra, and red nucleus reflected higher microstructural complexity and directionality compared with the putamen, caudate nucleus, and thalamus. In particular, the unique age-related positive correlations for fractional anisotropy, mean kurtosis, and radial kurtosis in the putamen opposite to those in other regions call for further investigation of exact underlying mechanisms. In summary, the results suggested that diffusional kurtosis can provide measurements in a new dimension that were complementary to diffusivity metrics. Kurtosis together with diffusivity can more comprehensively characterize microstructural compositions and age-related changes than diffusivity alone. Combined with proper model, it may also assist in providing neurobiological interpretations of the identified alterations. PMID:24910392

Gong, Nan-Jie; Wong, Chun-Sing; Chan, Chun-Chung; Leung, Lam-Ming; Chu, Yiu-Ching

2014-10-01

80

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

2012-08-01

81

Episodic memory function is associated with multiple measures of white matter integrity in cognitive aging  

PubMed Central

Previous neuroimaging research indicates that white matter injury and integrity, measured respectively by white matter hyperintensities (WMH) and fractional anisotropy (FA) obtained from diffusion tensor imaging (DTI), differ with aging and cerebrovascular disease (CVD) and are associated with episodic memory deficits in cognitively normal older adults. However, knowledge about tract-specific relationships between WMH, FA, and episodic memory in aging remains limited. We hypothesized that white matter connections between frontal cortex and subcortical structures as well as connections between frontal and temporo-parietal cortex would be most affected. In the current study, we examined relationships between WMH, FA and episodic memory in 15 young adults, 13 elders with minimal WMH and 15 elders with extensive WMH, using an episodic recognition memory test for object-color associations. Voxel-based statistics were used to identify voxel clusters where white matter measures were specifically associated with variations in episodic memory performance, and white matter tracts intersecting these clusters were analyzed to examine white matter-memory relationships. White matter injury and integrity measures were significantly associated with episodic memory in extensive regions of white matter, located predominantly in frontal, parietal, and subcortical regions. Template based tractography indicated that white matter injury, as measured by WMH, in the uncinate and inferior longitudinal fasciculi were significantly negatively associated with episodic memory performance. Other tracts such as thalamo-frontal projections, superior longitudinal fasciculus, and dorsal cingulum bundle demonstrated strong negative associations as well. The results suggest that white matter injury to multiple pathways, including connections of frontal and temporal cortex and frontal-subcortical white matter tracts, plays a critical role in memory differences seen in older individuals.

Lockhart, Samuel N.; Mayda, Adriane B. V.; Roach, Alexandra E.; Fletcher, Evan; Carmichael, Owen; Maillard, Pauline; Schwarz, Christopher G.; Yonelinas, Andrew P.; Ranganath, Charan; DeCarli, Charles

2011-01-01

82

Developmental regulation of alpha-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid receptor subunit expression in forebrain and relationship to regional susceptibility to hypoxic/ischemic injury. I. Rodent cerebral white matter and cortex.  

PubMed

This is the first part of a two-part study to investigate the cellular distribution and temporal regulation of alpha-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid receptor (AMPAR) subunits in the developing white matter and cortex in rat (part I) and human (part II). Western blot and immunocytochemistry were used to evaluate the differential expression of AMPAR subunits on glial and neuronal subtypes during the first 3 postnatal weeks in the Long Evans and Sprague Dawley rat strains. In Long Evans rats during the first postnatal week, GluR2-lacking AMPARs were expressed predominantly on white matter cells, including radial glia, premyelinating oligodendrocytes, and subplate neurons, whereas, during the second postnatal week, these AMPARs were highly expressed on cortical neurons, coincident with decreased expression on white matter cells. Immunocytochemical analysis revealed that cell-specific developmental changes in AMPAR expression occurred 2-3 days earlier by chronological age in Sprague Dawley rats compared with Long Evans rats, despite overall similar temporal sequencing. In both white and gray matter, the periods of high GluR2 deficiency correspond to those of regional susceptibility to hypoxic/ischemic injury in each of the two rat strains, supporting prior studies suggesting a critical role for Ca2+-permeable AMPARs in excitotoxic cellular injury and epileptogenesis. The developmental regulation of these receptor subunits strongly suggests that Ca2+ influx through GluR2-lacking AMPARs may play an important role in neuronal and glial development and injury in the immature brain. Moreover, as demonstrated in part II, there are striking similarities between rat and human in the regional and temporal maturational regulation of neuronal and glial AMPAR expression. PMID:16680782

Talos, Delia M; Fishman, Rachel E; Park, Hyunkyung; Folkerth, Rebecca D; Follett, Pamela L; Volpe, Joseph J; Jensen, Frances E

2006-07-01

83

Myelin membrane from adrenoleukodystrophy brain white matter--biochemical properties.  

PubMed

Adrenoleukodystrophy (ALD) is an X-linked progressive neurological disorder characterized by the accumulation of saturated very-long-chain fatty acids (C24 to C30) in lipids, especially cholesterol esters of the brain white matter and adrenal cortex. In the present study we have investigated the localization of accumulated cholesterol esters in brain white matter. During isolation of purified myelin membrane from regions of active demyelination, significant enrichment in cholesterol ester was found in two fractions, mainly in a low-density floating fraction and to a lesser degree in the purified myelin preparation. The fatty acid composition of cholesterol esters from both the ALD floating and myelin fractions was enriched approximately 10-fold in saturated very-long-chain fatty acids (greater than or equal to C24) compared with control preparations. PMID:6875541

Brown, F R; Chen, W W; Kirschner, D A; Frayer, K L; Powers, J M; Moser, A B; Moser, H W

1983-08-01

84

White matter lesions in Parkinson disease  

PubMed Central

Pure vascular parkinsonism without evidence of nigral Lewy body pathology may occur as a distinct clinicopathological entity, but a much more frequent occurrence is the comorbid presence of age-associated white matter lesions (WMLs) in idiopathic Parkinson disease (PD). WMLs are associated with motor and cognitive symptoms in otherwise normal elderly individuals. Comorbid WMLs are, therefore, expected to contribute to clinical symptoms in PD. Studies of WMLs in PD differ with regard to methods of assessment of WML burden and the patient populations selected for analysis, but converging evidence suggests that postural stability and gait motor functions are predominantly affected. WMLs are described to contribute to dementia in Alzheimer disease, and emerging but inconclusive evidence indicates similar effects in PD. In this article, we review the literature addressing the occurrence and impact of WMLs in PD, and suggest that WMLs may exacerbate or contribute to some motor and cognitive deficits associated with PD. We review existing and emerging methods for studying white matter pathology in vivo, and propose future research directions.

Bohnen, Nicolaas I.; Albin, Roger L.

2013-01-01

85

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

2013-01-01

86

Computational Representation of White Matter Fiber Orientations  

PubMed Central

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.

Ferreira da Silva, Adelino R.

2013-01-01

87

Localisation of increased prefrontal white matter in pathological liars  

PubMed Central

Summary We examined white matter volumes in four prefrontal subregions using structural magnetic resonance imaging in 10 pathological liars, 14 antisocial controls, and 20 normal controls. Liars showed a relatively widespread increase in white matter (23–36%) in orbitofrontal, middle and inferior, but not superior, frontal gyri compared with antisocial and normal controls. This white matter increase may predispose some individuals to pathological lying.

YANG, YALING; RAINE, ADRIAN; NARR, KATHERINE L.; LENCZ, TODD; LaCASSE, LORI; COLLETTI, PATRICK; TOGA, ARTHUR W.

2008-01-01

88

Gray and white matter correlates of navigational ability in humans.  

PubMed

Humans differ widely in their navigational abilities. Studies have shown that self-reports on navigational abilities are good predictors of performance on navigation tasks in real and virtual environments. The caudate nucleus and medial temporal lobe regions have been suggested to subserve different navigational strategies. The ability to use different strategies might underlie navigational ability differences. This study examines the anatomical correlates of self-reported navigational ability in both gray and white matter. Local gray matter volume was compared between a group (N = 134) of good and bad navigators using voxel-based morphometry (VBM), as well as regional volumes. To compare between good and bad navigators, we also measured white matter anatomy using diffusion tensor imaging (DTI) and looked at fractional anisotropy (FA) values. We observed a trend toward higher local GM volume in right anterior parahippocampal/rhinal cortex for good versus bad navigators. Good male navigators showed significantly higher local GM volume in right hippocampus than bad male navigators. Conversely, bad navigators showed increased FA values in the internal capsule, the white matter bundle closest to the caudate nucleus and a trend toward higher local GM volume in the caudate nucleus. Furthermore, caudate nucleus regional volume correlated negatively with navigational ability. These convergent findings across imaging modalities are in line with findings showing that the caudate nucleus and the medial temporal lobes are involved in different wayfinding strategies. Our study is the first to show a link between self-reported large-scale navigational abilities and different measures of brain anatomy. Hum Brain Mapp 35:2561-2572, 2014. © 2013 Wiley Periodicals, Inc. PMID:24038667

Wegman, Joost; Fonteijn, Hubert M; van Ekert, Janneke; Tyborowska, Anna; Jansen, Clemens; Janzen, Gabriele

2014-06-01

89

Cerebral White Matter Integrity and Cognitive Aging: Contributions from Diffusion Tensor Imaging  

PubMed Central

The integrity of cerebral white matter is critical for efficient cognitive functioning, but little is known regarding the role of white matter integrity in age-related differences in cognition. Diffusion tensor imaging (DTI) measures the directional displacement of molecular water and as a result can characterize the properties of white matter that combine to restrict diffusivity in a spatially coherent manner. This review considers DTI studies of aging and their implications for understanding adult age differences in cognitive performance. Decline in white matter integrity contributes to a disconnection among distributed neural systems, with a consistent effect on perceptual speed and executive functioning. The relation between white matter integrity and cognition varies across brain regions, with some evidence suggesting that age-related effects exhibit an anterior-posterior gradient. With continued improvements in spatial resolution and integration with functional brain imaging, DTI holds considerable promise, both for theories of cognitive aging and for translational application.

Madden, David J.; Bennett, Ilana J.; Song, Allen W.

2009-01-01

90

Disrupted white matter in language and motor tracts in developmental stuttering.  

PubMed

White matter tracts connecting areas involved in speech and motor control were examined using diffusion-tensor imaging in a sample of people who stutter (n=29) who were heterogeneous with respect to age, sex, handedness and stuttering severity. The goals were to replicate previous findings in developmental stuttering and to extend our knowledge by evaluating the relationship between white matter differences in people who stutter and factors such as age, sex, handedness and stuttering severity. We replicated previous findings that showed reduced integrity in white matter underlying ventral premotor cortex, cerebral peduncles and posterior corpus callosum in people who stutter relative to controls. Tractography analysis additionally revealed significantly reduced white matter integrity in the arcuate fasciculus bilaterally and the left corticospinal tract and significantly reduced connectivity within the left corticobulbar tract in people who stutter. Region-of-interest analyses revealed reduced white matter integrity in people who stutter in the three pairs of cerebellar peduncles that carry the afferent and efferent fibers of the cerebellum. Within the group of people who stutter, the higher the stuttering severity index, the lower the white matter integrity in the left angular gyrus, but the greater the white matter connectivity in the left corticobulbar tract. Also, in people who stutter, handedness and age predicted the integrity of the corticospinal tract and peduncles, respectively. Further studies are needed to determine which of these white matter differences relate to the neural basis of stuttering and which reflect experience-dependent plasticity. PMID:23819900

Connally, Emily L; Ward, David; Howell, Peter; Watkins, Kate E

2014-04-01

91

Explicating the Face Perception Network with White Matter Connectivity  

PubMed Central

A network of multiple brain regions is recruited in face perception. Our understanding of the functional properties of this network can be facilitated by explicating the structural white matter connections that exist between its functional nodes. We accomplished this using functional MRI (fMRI) in combination with fiber tractography on high angular resolution diffusion weighted imaging data. We identified the three nodes of the core face network: the “occipital face area” (OFA), the “fusiform face area” (mid-fusiform gyrus or mFus), and the superior temporal sulcus (STS). Additionally, a region of the anterior temporal lobe (aIT), implicated as being important for face perception was identified. Our data suggest that we can further divide the OFA into multiple anatomically distinct clusters – a partitioning consistent with several recent neuroimaging results. More generally, structural white matter connectivity within this network revealed: 1) Connectivity between aIT and mFus, and between aIT and occipital regions, consistent with studies implicating this posterior to anterior pathway as critical to normal face processing; 2) Strong connectivity between mFus and each of the occipital face-selective regions, suggesting that these three areas may subserve different functional roles; 3) Almost no connectivity between STS and mFus, or between STS and the other face-selective regions. Overall, our findings suggest a re-evaluation of the “core” face network with respect to what functional areas are or are not included in this network.

Pyles, John A.; Verstynen, Timothy D.; Schneider, Walter; Tarr, Michael J.

2013-01-01

92

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

93

Reproducibility of quantitative tractography methods applied to cerebral white matter  

Microsoft Academic Search

Tractography based on diffusion tensor imaging (DTI) allows visualization of white matter tracts. In this study, protocols to reconstruct eleven major white matter tracts are described. The protocols were refined by several iterations of intra- and inter-rater measurements and identification of sources of variability. Reproducibility of the established protocols was then tested by raters who did not have previous experience

Setsu Wakana; Arvind Caprihan; Martina M. Panzenboeck; James H. Fallon; Michele Perry; Randy L. Gollub; Kegang Hua; Jiangyang Zhang; Hangyi Jiang; Prachi Dubey; Ari Blitz; Peter van Zijl; Susumu Mori

2007-01-01

94

Oligodendrocyte genes, white matter tract integrity, and cognition in schizophrenia.  

PubMed

Oligodendrocyte genes and white matter tracts have been implicated in the pathophysiology of schizophrenia and may play an important etiopathogenic role in cognitive dysfunction in schizophrenia. The objective of the present study in 60 chronic schizophrenia patients individually matched to 60 healthy controls was to determine whether 1) white matter tract integrity influences cognitive performance, 2) oligodendrocyte gene variants influence white matter tract integrity and cognitive performance, and 3) effects of oligodendrocyte gene variants on cognitive performance are mediated via white matter tract integrity. We used the partial least-squares multivariate approach to ascertain relationships among oligodendrocyte gene variants, integrity of cortico-cortical and subcortico-cortical white matter tracts, and cognitive performance. Robust relationships among oligodendrocyte gene variants, white matter tract integrity, and cognitive performance were found in both patients and controls. We also showed that effects of gene variants on cognitive performance were mediated by the integrity of white matter tracts. Our results were strengthened by bioinformatic analyses of gene variant function. To our knowledge, this is the first study that has brought together these lines of investigation in the same population and highlights the importance of the oligodendrocyte/white matter pathway in schizophrenia, particularly as it pertains to cognitive function. PMID:22772651

Voineskos, Aristotle N; Felsky, Daniel; Kovacevic, Natasa; Tiwari, Arun K; Zai, Clement; Chakravarty, M Mallar; Lobaugh, Nancy J; Shenton, Martha E; Rajji, Tarek K; Miranda, Dielle; Pollock, Bruce G; Mulsant, Benoit H; McIntosh, Anthony R; Kennedy, James L

2013-09-01

95

Developmental regulation of alpha-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid receptor subunit expression in forebrain and relationship to regional susceptibility to hypoxic/ischemic injury. II. Human cerebral white matter and cortex.  

PubMed

This report is the second of a two-part evaluation of developmental differences in alpha-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid receptor (AMPAR) subunit expression in cell populations within white matter and cortex. In part I, we reported that, in rat, developmental expression of Ca2+-permeable (GluR2-lacking) AMPARs correlated at the regional and cellular level with increased susceptibility to hypoxia/ischemia (H/I), suggesting an age-specific role of these receptors in the pathogenesis of brain injury. Part II examines the regional and cellular progression of AMPAR subunits in human white matter and cortex from midgestation through early childhood. Similarly to the case in the rodent, there is a direct correlation between selective vulnerability to H/I and expression of GluR2-lacking AMPARs in human brain. For midgestational cases aged 20-24 postconceptional weeks (PCW) and for premature infants (25-37 PCW), we found that radial glia, premyelinating oligodendrocytes, and subplate neurons transiently expressed GluR2-lacking AMPARs. Notably, prematurity represents a developmental window of selective vulnerability for white matter injury, such as periventricular leukomalacia (PVL). During term (38-42 PCW) and postterm neonatal (43-46 PCW) periods, age windows characterized by increased susceptibility to cortical injury and seizures, GluR2 expression was low in the neocortex, specifically on cortical pyramidal and nonpyramidal neurons. This study indicates that Ca2+-permeable AMPAR blockade may represent an age-specific therapeutic strategy for potential use in humans. Furthermore, these data help to validate specific rodent maturational stages as appropriate models for evaluation of H/I pathophysiology. PMID:16680761

Talos, Delia M; Follett, Pamela L; Folkerth, Rebecca D; Fishman, Rachel E; Trachtenberg, Felicia L; Volpe, Joseph J; Jensen, Frances E

2006-07-01

96

Non-Gaussian water diffusion in aging white matter.  

PubMed

Age-associated white matter degeneration has been well documented and is likely an important mechanism contributing to cognitive decline in older adults. Recent work has explored a range of noninvasive neuroimaging procedures to differentially highlight alterations in the tissue microenvironment. Diffusional kurtosis imaging (DKI) is an extension of diffusion tensor imaging (DTI) that accounts for non-Gaussian water diffusion and can reflect alterations in the distribution and diffusion properties of tissue compartments. We used DKI to produce whole-brain voxel-based maps of mean, axial, and radial diffusional kurtoses, quantitative indices of the tissue microstructure's diffusional heterogeneity, in 111 participants ranging from the age of 33 to 91 years. As suggested from prior DTI studies, greater age was associated with alterations in white-matter tissue microstructure, which was reflected by a reduction in all 3 DKI metrics. Prominent effects were found in prefrontal and association white matter compared with relatively preserved primary motor and visual areas. Although DKI metrics co-varied with DTI metrics on a global level, DKI provided unique regional sensitivity to the effects of age not available with DTI. DKI metrics were additionally useful in combination with DTI metrics for the classification of regions according to their multivariate "diffusion footprint", or pattern of relative age effect sizes. It is possible that the specific multivariate patterns of age-associated changes measured are representative of different types of microstructural pathology. These results suggest that DKI provides important complementary indices of brain microstructure for the study of brain aging and neurologic disease. PMID:24378085

Coutu, Jean-Philippe; Chen, J Jean; Rosas, H Diana; Salat, David H

2014-06-01

97

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

2009-09-30

98

White matter fiber tractography based on a directional diffusion field in diffusion tensor MRI  

NASA Astrophysics Data System (ADS)

Diffusion tensor (DT) MRI provides the directional information of water molecular diffusion, which can be utilized to estimate the connectivity of white matter tract pathways in the human brain. Several white matter tractography methods have been developed to reconstruct the white matter fiber tracts using DT-MRI. With conventional methods (e.g., streamline techniques), however, it would be very difficult to trace the white matter tracts passing through the fiber crossing and branching regions due to the ambiguous directional information with the partial volume effect. The purpose of this study was to develop a new white matter tractography method which permits fiber tract branching and passing through crossing regions. Our tractography method is based on a three-dimensional (3D) directional diffusion function (DDF), which was defined by three eigenvalues and their corresponding eigenvectors of DT in each voxel. The DDF-based tractography (DDFT) consists of the segmentation of white matter tract region and fiber tracking process. The white matter tract regions were segmented by thresholding the 3D directional diffusion field, which was generated by the DDF. In fiber tracking, the DDFT method estimated the local tract direction based on overlap of the DDFs instead of the principal eigenvector, which has been used in conventional methods, and reconstructed tract branching by means of a one-to-many relation model. To investigate the feasibility and usefulness of the DDFT method, we applied it to DT-MRI data of five normal subjects and seven patients with a brain tumor. With the DDFT method, the detailed anatomy of white matter tracts was depicted more appropriately than the conventional methods.

Kumazawa, S.; Yoshiura, T.; Arimura, H.; Mihara, F.; Honda, H.; Higashida, Y.; Toyofuku, F.

2006-03-01

99

Aging of Cerebral White Matter: A Review of MRI Findings  

PubMed Central

Background Cerebral aging is a complex and heterogeneous process that is associated with a high degree of inter-individual variability. Structural magnetic resonance imaging (MRI) can be used to identify and quantify non-disease-related aging of the cerebral white matter. Methods The present article reviews the findings from several MRI techniques, including morphometric approaches, study of white matter hyperintensities, diffusion tensor imaging, and magnetization transfer imaging that have been used to examine aging of the cerebral white matter. Furthermore, the relationship of MRI indices of white matter integrity to age-related cognitive declines is reported. Results A general pattern of age-related preservation and decline emerges indicating that the prefrontal white matter is most susceptible to the influence of age. Studies that combine MRI with cognitive measures suggest that such age-related reductions in white matter integrity may produce a disconnection state that underlies some of the age-related performance declines in age-sensitive cognitive domains. Conclusions White matter aging may contribute to a disconnection state that is associated with declines in episodic memory, executive functions, and information processing speed.

Gunning-Dixon, Faith M.; Brickman, Adam M.; Cheng, Janice C.; Alexopoulos, George S.

2008-01-01

100

Alcohol use and cerebral white matter compromise in adolescence.  

PubMed

Alcohol use is typically initiated during adolescence, a period known to be critical in neurodevelopment. The adolescent brain may be particularly susceptible to the harmful effects of alcohol. While the cognitive deficits associated with alcohol use during adolescence have been well-documented, the neural substrates underlying these effects remain inadequately understood. Cerebral white matter has been suggested as a primary site of alcohol-related damage and diffusion tensor imaging (DTI) allows for the quantification of white matter integrity in vivo. This review summarizes results from both cross-sectional and longitudinal studies employing DTI that indicate that white matter tracts, particularly those thought to be involved in executive functioning, continue to develop throughout adolescence and into adulthood. Numerous DTI studies reveal a positive correlation between white matter integrity and neurocognitive performance and, in adults, the detrimental effects of prolonged alcohol-dependence on white matter integrity. We provide a comprehensive review of the DTI studies exploring the relationship between alcohol use and white matter integrity in adolescents. Results from most of these studies suggest that alcohol use is associated with reduced white matter integrity, particularly in the superior longitudinal fasciculus (SLF), and some evidence suggests that this relationship may be influenced by sex. We conclude by highlighting confounds and limitations of the available research and suggesting directions for future research. PMID:23583835

Elofson, Jonathan; Gongvatana, Win; Carey, Kate B

2013-07-01

101

Alcohol Use and Cerebral White Matter Compromise in Adolescence  

PubMed Central

Alcohol use is typically initiated during adolescence, a period known to be critical in neurodevelopment. The adolescent brain may be particularly susceptible to the harmful effects of alcohol. While the cognitive deficits associated with alcohol use during adolescence have been well-documented, the neural substrates underlying these effects remain inadequately understood. Cerebral white matter has been suggested as a primary site of alcohol-related damage and diffusion tensor imaging (DTI) allows for the quantification of white matter integrity in vivo. This review summarizes results from both cross-sectional and longitudinal studies employing DTI that indicate that white matter tracts, particularly those thought to be involved in executive functioning, continue to develop throughout adolescence and into adulthood. Numerous DTI studies reveal a positive correlation between white matter integrity and neurocognitive performance and, in adults, the detrimental effects of prolonged alcohol-dependence on white matter integrity. We provide a comprehensive review of the DTI studies exploring the relationship between alcohol use and white matter integrity in adolescents. Results from most of these studies suggest that alcohol use is associated with reduced white matter integrity, particularly in the superior longitudinal fasciculus (SLF), and some evidence suggests that this relationship may be influenced by sex. We conclude by highlighting confounds and limitations of the available research and suggesting directions for future research.

Elofson, Jonathan; Gongvatana, Win; Carey, Kate B.

2013-01-01

102

White matter damage and cognitive impairment after traumatic brain injury  

PubMed Central

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.

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

2011-01-01

103

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

PubMed Central

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 10 months through 4 years of age, who were either exclusively breastfed a minimum of 3 months; 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.

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

2013-01-01

104

Frontal White Matter and Cingulum Diffusion Tensor Imaging Deficits in Alcoholism  

PubMed Central

Background Alcoholism-related deficits in cognition and emotion point toward frontal and limbic dysfunction, particularly in the right hemisphere. Prefrontal and anterior cingulate cortices are involved in cognitive and emotional functions and play critical roles in the oversight of the limbic reward system. In the present study, we examined the integrity of white matter tracts that are critical to frontal and limbic connectivity. Methods Diffusion tensor magnetic resonance imaging (DT-MRI) was used to assess functional anisotropy (FA), a measure of white matter integrity, in 15 abstinent long-term chronic alcoholic and 15 demographically equivalent control men. Voxel-based and region-based analyses of group FA differences were applied to these scans. Results Alcoholic subjects had diminished frontal lobe FA in the right superior longitudinal fascicles II and III, orbitofrontal cortex white matter, and cingulum bundle, but not in corresponding left hemisphere regions. These right frontal and cingulum white matter regional FA measures provided 97% correct group discrimination. Working Memory scores positively correlated with superior longitudinal fascicle III FA measures in control subjects only. Conclusions The findings demonstrate white matter microstructure deficits in abstinent alcoholic men in several right hemisphere tracts connecting prefrontal and limbic systems. These white matter deficits may contribute to underlying dysfunction in memory, emotion, and reward response in alcoholism.

Harris, Gordon J.; Jaffin, Sharon Kim; Hodge, Steven M.; Kennedy, David; Caviness, Verne S.; Marinkovic, Ksenija; Papadimitriou, George M.; Makris, Nikos; Oscar-Berman, Marlene

2014-01-01

105

White matter microstructure alterations: a study of alcoholics with and without post-traumatic stress disorder.  

PubMed

Many brain imaging studies have demonstrated reductions in gray and white matter volumes in alcoholism, with fewer investigators using diffusion tensor imaging (DTI) to examine the integrity of white matter pathways. Among various medical conditions, alcoholism and post-traumatic stress disorder (PTSD) are two comorbid diseases that have similar degenerative effects on the white matter integrity. Therefore, understanding and differentiating these effects would be very important in characterizing alcoholism and PTSD. Alcoholics are known to have neurocognitive deficits in decision-making, particularly in decisions related to emotionally-motivated behavior, while individuals with PTSD have deficits in emotional regulation and enhanced fear response. It is widely believed that these types of abnormalities in both alcoholism and PTSD are related to fronto-limbic dysfunction. In addition, previous studies have shown cortico-limbic fiber degradation through fiber tracking in alcoholism. DTI was used to measure white matter fractional anisotropy (FA), which provides information about tissue microstructure, possibly indicating white matter integrity. We quantitatively investigated the microstructure of white matter through whole brain DTI analysis in healthy volunteers (HV) and alcohol dependent subjects without PTSD (ALC) and with PTSD (ALC+PTSD). These data show significant differences in FA between alcoholics and non-alcoholic HVs, with no significant differences in FA between ALC and ALC+PTSD in any white matter structure. We performed a post-hoc region of interest analysis that allowed us to incorporate multiple covariates into the analysis and found similar results. HV had higher FA in several areas implicated in the reward circuit, emotion, and executive functioning, suggesting that there may be microstructural abnormalities in white matter pathways that contribute to neurocognitive and executive functioning deficits observed in alcoholics. Furthermore, our data do not reveal any differences between ALC and ALC+PTSD, suggesting that the effect of alcohol on white matter microstructure may be more significant than any effect caused by PTSD. PMID:24260518

Durkee, Caitlin A; Sarlls, Joelle E; Hommer, Daniel W; Momenan, Reza

2013-01-01

106

MR Diffusion Tensor Imaging: A Window into White Matter Integrity of the Working Brain  

PubMed Central

As Norman Geschwind asserted in 1965, syndromes resulting from white matter lesions could produce deficits in higher-order functions and “disconnexion” or the interruption of connection between gray matter regions could be as disruptive as trauma to those regions per se. The advent of in vivo diffusion tensor imaging, which allows quantitative characterization of white matter fiber integrity in health and disease, has served to strengthen Geschwind's proposal. Here we present an overview of the principles of diffusion tensor imaging (DTI) and its contribution to progress in our current understanding of normal and pathological brain function.

Chanraud, Sandra; Zahr, Natalie; Pfefferbaum, Adolf

2010-01-01

107

Individual differences in left parietal white matter predict math scores on the Preliminary Scholastic Aptitude Test.  

PubMed

Mathematical skills are of critical importance, both academically and in everyday life. Neuroimaging research has primarily focused on the relationship between mathematical skills and functional brain activity. Comparatively few studies have examined which white matter regions support mathematical abilities. The current study uses diffusion tensor imaging (DTI) to test whether individual differences in white matter predict performance on the math subtest of the Preliminary Scholastic Aptitude Test (PSAT). Grades 10 and 11 PSAT scores were obtained from 30 young adults (ages 17-18) with wide-ranging math achievement levels. Tract based spatial statistics was used to examine the correlation between PSAT math scores, fractional anisotropy (FA), radial diffusivity (RD) and axial diffusivity (AD). FA in left parietal white matter was positively correlated with math PSAT scores (specifically in the left superior longitudinal fasciculus, left superior corona radiata, and left corticospinal tract) after controlling for chronological age and same grade PSAT critical reading scores. Furthermore, RD, but not AD, was correlated with PSAT math scores in these white matter microstructures. The negative correlation with RD further suggests that participants with higher PSAT math scores have greater white matter integrity in this region. Individual differences in FA and RD may reflect variability in experience dependent plasticity over the course of learning and development. These results are the first to demonstrate that individual differences in white matter are associated with mathematical abilities on a nationally administered scholastic aptitude measure. PMID:23108272

Matejko, Anna A; Price, Gavin R; Mazzocco, Michèle M M; Ansari, Daniel

2012-10-27

108

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

109

Valproic acid increases white matter repair and neurogenesis after stroke  

PubMed Central

Acute treatment of stroke with HDAC inhibitors has been shown to reduce ischemic cell damage; however, it is unclear whether delayed treatment with HDAC inhibitors will contribute to the brain repair and plasticity. In the present study, we investigated the effects of delayed treatment of stroke with a pan HDAC inhibitor, valproic acid (VPA), on white matter injury and neurogenesis during stroke recovery. Administration of VPA at a dose of 100 mg/kg for 7 days starting 24 hours after middle cerebral artery occlusion (MCAo) in rats significantly improved neurological outcome measured 7 to 28 days post-MCAo. In addition, the VPA treatment significantly increased oligodendrocyte survival and newly generated oligodendrocytes, which was associated with elevation of myelinated axonal density in the ischemic boundary 28 days after MCAo. VPA treatment also increased the expression of glutamate transporter 1 (GLT1) in the ischemic boundary after stroke, and increased acetylated histone H4 expression in neuroblasts and the number of new neurons in striatal ischemic boundary region. This study provides new evidence that the delayed VPA treatment enhances white matter repair and neurogenesis in ischemic brain, which may contribute to improved functional outcome.

Liu, Xian Shuang; Chopp, Michael; Kassis, Haifa; Jia, Long Fei; Hozeska-Solgot, Ann; Zhang, Rui Lan; Chen, Charlie; Cui, Yi Sheng; Zhang, Zheng Gang

2012-01-01

110

Valproic acid increases white matter repair and neurogenesis after stroke.  

PubMed

Acute treatment of stroke with histone deacetylase (HDAC) inhibitors has been shown to reduce ischemic cell damage; however, it is unclear whether delayed treatment with HDAC inhibitors will contribute to the brain repair and plasticity. In the present study, we investigated the effects of delayed treatment of stroke with a pan HDAC inhibitor, valproic acid (VPA), on white matter injury and neurogenesis during stroke recovery. Administration of VPA at a dose of 100mg/kg for 7 days starting 24h after middle cerebral artery occlusion (MCAo) in rats significantly improved neurological outcome measured 7-28 days post-MCAo. In addition, the VPA treatment significantly increased oligodendrocyte survival and newly generated oligodendrocytes, which was associated with elevation of myelinated axonal density in the ischemic boundary 28 days after MCAo. VPA treatment also increased the expression of glutamate transporter 1 (GLT1) in the ischemic boundary after stroke, and increased acetylated histone H4 expression in neuroblasts and the number of new neurons in striatal ischemic boundary region. This study provides new evidence that the delayed VPA treatment enhances white matter repair and neurogenesis in ischemic brain, which may contribute to improved functional outcome. PMID:22704966

Liu, X S; Chopp, M; Kassis, H; Jia, L F; Hozeska-Solgot, A; Zhang, R L; Chen, C; Cui, Y S; Zhang, Z G

2012-09-18

111

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

112

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

113

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

2013-01-01

114

White matter integrity deficits in prefrontal-amygdala pathways in Williams syndrome.  

PubMed

Williams syndrome is a neurodevelopmental disorder associated with significant non-social fears. Consistent with this elevated non-social fear, individuals with Williams syndrome have an abnormally elevated amygdala response when viewing threatening non-social stimuli. In typically-developing individuals, amygdala activity is inhibited through dense, reciprocal white matter connections with the prefrontal cortex. Neuroimaging studies suggest a functional uncoupling of normal prefrontal-amygdala inhibition in individuals with Williams syndrome, which might underlie both the extreme amygdala activity and non-social fears. This functional uncoupling might be caused by structural deficits in underlying white matter pathways; however, prefrontal-amygdala white matter deficits have yet to be explored in Williams syndrome. We used diffusion tensor imaging to investigate prefrontal-amygdala white matter integrity differences in individuals with Williams syndrome and typically-developing controls with high levels of non-social fear. White matter pathways between the amygdala and several prefrontal regions were isolated using probabilistic tractography. Within each pathway, we tested for between-group differences in three measures of white matter integrity: fractional anisotropy (FA), radial diffusivity (RD), and parallel diffusivity (?(1)). Individuals with Williams syndrome had lower FA, compared to controls, in several of the prefrontal-amygdala pathways investigated, indicating a reduction in white matter integrity. Lower FA in Williams syndrome was explained by significantly higher RD, with no differences in ?(1), suggestive of lower fiber density or axon myelination in prefrontal-amygdala pathways. These results suggest that deficits in the structural integrity of prefrontal-amygdala white matter pathways might underlie the increased amygdala activity and extreme non-social fears observed in Williams syndrome. PMID:22008369

Avery, Suzanne N; Thornton-Wells, Tricia A; Anderson, Adam W; Blackford, Jennifer Urbano

2012-01-16

115

ASSOCIATION BETWEEN WHITE MATTER MICROSTRUCTURE, EXECUTIVE FUNCTIONS AND PROCESSING SPEED IN OLDER ADULTS: THE IMPACT OF VASCULAR HEALTH  

PubMed Central

Cerebral white matter damage is a commonly reported consequence of healthy aging, but is also associated with cognitive decline and dementia. The aetiology of this damage is unclear, however, individuals with hypertension have a greater burden of white matter signal abnormalities (WMSA) on MR imaging than those without hypertension. It is therefore possible that elevated blood pressure (BP) impacts white matter tissue structure which in turn has a negative impact on cognition. However, little information exists about whether vascular health indexed by BP mediates the relationship between cognition and white matter tissue structure. We used diffusion tensor imaging to examine the impact of vascular health on regional associations between white matter integrity and cognition in healthy older adults spanning the normotensive to moderate-severe hypertensive BP range (43–87 years; N=128). We examined how white matter structure was associated with performance on tests of two cognitive domains, executive functioning (EF) and processing speed (PS), and how patterns of regional associations were modified by BP and WMSA. Multiple linear regression and structural equation models demonstrated associations between tissue structure, EF and PS in frontal, temporal, parietal and occipital white matter regions. Radial diffusivity was more prominently associated with performance than axial diffusivity. BP only minimally influenced the relationship between white matter integrity, EF and PS. However, WMSA volume had a major impact on neurocognitive associations. This suggests that, although BP and WMSA are causally related, these differential metrics of vascular health may act via independent pathways to influence brain structure, EF and PS.

Jacobs, Heidi I.L.; Leritz, Elizabeth C.; Williams, Victoria J.; Van Boxtel, Martin P.J.; van der Elst, Wim; Jolles, Jelle; Verhey, Frans R. J.; McGlinchey, Regina E.; Milberg, William P.; Salat, David H.

2013-01-01

116

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

2013-03-30

117

A voxel-based diffusion tensor imaging study of white matter in bipolar disorder.  

PubMed

There is evidence from post-mortem and magnetic resonance imaging studies that hyperintensities, oligodendroglial abnormalities, and gross white matter volumetric alterations are involved in the pathophysiology of bipolar disorder. There is also functional imaging evidence for a defect in frontal cortico-subcortical pathways in bipolar disorder, but the white matter comprising these pathways has not been well investigated. Few studies have investigated white matter integrity in patients with bipolar disorder compared to healthy volunteers and the majority of studies have used manual region-of-interest approaches. In this study, we compared fractional anisotropy (FA) values between 30 patients with bipolar disorder and 38 healthy volunteers in the brain white matter using a voxelwise analysis following intersubject registration to Talairach space. Compared to healthy volunteers, patients demonstrated significantly (p<0.001; cluster size > or =50) higher FA within the right and left frontal white matter and lower FA within the left cerebellar white matter. Examination of individual eigenvalues indicated that group differences in both axial diffusivity and radial diffusivity contributed to abnormal FA within these regions. Tractography was performed in template space on averaged diffusion tensor imaging data from all individuals. Extraction of bundles passing through the clusters that differed significantly between groups suggested that white matter abnormalities along the pontine crossing tract, corticospinal/corticopontine tracts, and thalamic radiation fibers may be involved in the pathogenesis of bipolar disorder. Our findings are consistent with models of bipolar disorder that implicate dysregulation of cortico-subcortical and cerebellar regions in the disorder and may have relevance for phenomenology. PMID:19145224

Mahon, Katie; Wu, Jinghui; Malhotra, Anil K; Burdick, Katherine E; DeRosse, Pamela; Ardekani, Babak A; Szeszko, Philip R

2009-05-01

118

Genetic white matter fiber tractography with global optimization.  

PubMed

Diffusion tensor imaging (DTI) tractography is a novel technique that can delineate the trajectories between cortical region of the human brain non-invasively. In this paper, a novel DTI based white matter fiber tractography using genetic algorithm is presented. Adapting the concepts from evolutionary biology which include selection, recombination and mutation, globally optimized fiber pathways are generated iteratively. Global optimality of the fiber tracts is evaluated using Bayes decision rule, which simultaneously considers both the fiber geometric smoothness and consistency with the tensor field. This global optimality assigns the tracking fibers great immunity to random image noise and other local image artifacts, thus avoiding the detrimental effects of cumulative noise on fiber tracking. Experiments with synthetic and in vivo human DTI data have demonstrated the feasibility and robustness of this new fiber tracking technique, and an improved performance over commonly used probabilistic fiber tracking. PMID:19666052

Wu, Xi; Xu, Qing; Xu, Lei; Zhou, Jiliu; Anderson, Adam W; Ding, Zhaohua

2009-11-15

119

Combined analysis of DTI and fMRI data reveals a joint maturation of white and grey matter in a fronto-parietal network  

Microsoft Academic Search

The aim of this study was to explore whether there are networks of regions where maturation of white matter and changes in brain activity show similar developmental trends during childhood. In a previous study, we showed that during childhood, grey matter activity increases in frontal and parietal regions. We hypothesized that this would be mediated by maturation of white matter.

Pernille J. Olesen; Zoltan Nagy; Helena Westerberg; Torkel Klingberg

2003-01-01

120

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

121

Relations between white matter maturation and reaction time in childhood.  

PubMed

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

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

2014-01-01

122

Effects of prenatal alcohol exposure on the development of white matter volume and change in executive function  

PubMed Central

Prenatal alcohol exposure can cause a wide range of deficits in executive function that persist throughout life, but little is known about how changes in brain structure relate to cognition in affected individuals. In the current study, we predicted that the rate of white matter volumetric development would be atypical in children with fetal alcohol spectrum disorders (FASD) when compared to typically developing children, and that the rate of change in cognitive function would relate to differential white matter development between groups. Data were available for 103 subjects [49 with FASD, 54 controls, age range 6–17, mean age = 11.83] with 153 total observations. Groups were age-matched. Participants underwent structural magnetic resonance imaging (MRI) and an executive function (EF) battery. Using white matter volumes measured bilaterally for frontal and parietal regions and the corpus callosum, change was predicted by modeling the effects of age, intracranial volume, sex, and interactions with exposure status and EF measures. While both groups showed regional increases in white matter volumes and improvement in cognitive performance over time, there were significant effects of exposure status on age-related relationships between white matter increases and EF measures. Specifically, individuals with FASD consistently showed a positive relationship between improved cognitive function and increased white matter volume over time, while no such relationships were seen in controls. These novel results relating improved cognitive function with increased white matter volume in FASD suggest that better cognitive outcomes could be possible for FASD subjects through interventions that enhance white matter plasticity.

Gautam, P.; Nunez, S.C.; Narr, K.L.; Kan, E.C.; Sowell, E.R.

2014-01-01

123

Surface based laminar analysis of diffusion abnormalities in cortical and white matter layers in neocortical epilepsy  

PubMed Central

Summary Purpose Microstructural alterations seen in the epileptic cortex have been implicated as a cause and also result of multiple seizure activity. In the present study, we evaluated water diffusion changes at different cortical thickness fractions and in the underlying white matter of the epileptic cortex and compared them with electrographically normal cortex and also with corresponding cortical regions of healthy controls. Methods We selected 18 children with normal MRI who underwent two-stage epilepsy surgery to control seizures of neocortical origin, and compared their MR images with those of 18 age-matched healthy controls. First, delineation of the grey-white and grey-pial intersection surfaces was performed on high-resolution volumetric T1 MR images. Using the delineated surfaces as reference, diffusion values were measured at different cortical thickness fractions and in the underlying white matter at various depths, using diffusion tensor imaging (DTI). Cortical regions representing seizure onset and electrographically normal cortex were differentiated by electrocorticography in the epilepsy patients. Key findings We observed different patterns of diffusion abnormalities in both the seizure onset and electrographically normal cortical regions when compared to healthy controls. In the seizure onset regions, a marked increase in diffusivity was noted in the cortical grey matter and this increase was most pronounced in the outer fraction of the grey matter. Similarly, increased diffusivity was noted in the white matter underlying the epileptic cortex. The electrographically normal cortex, in contrast, showed decreased diffusivity in inner and middle cortical fractions compared to the controls. The white matter underlying the electrographically normal cortex did not show any difference in diffusivity between the epileptic children and controls. Finally, both the cortical grey matter and the underlying white matter regions showed decreased anisotropy in epileptic as well as electrographically normal regions when compared to controls. Significance Our results suggest specific patterns of diffusion changes in the cortical fractions and the underlying white matter of the epileptic region compared to electrographically normal and normal control regions. The abnormal increase in diffusivity of the superficial cortex might be associated with microstructural abnormalities commonly seen in layers II through IV of epileptic cortex. Such combined use of a high-resolution structural image to extract the laminar diffusion values, which are highly sensitive to microstructural alterations, could be of clinical value in localizing epileptogenic cortex.

Govindan, Rajkumar Munian; Asano, Eishi; Juhasz, Csaba; Jeong, Jeong-won; Chugani, Harry T.

2013-01-01

124

Decreased white matter integrity in mesial temporal lobe epilepsy: a machine learning approach.  

PubMed

Statistical analysis on diffusion tensor imaging has been used extensively in mesial temporal lobe epilepsy (mTLE) and most studies report decrease in fractional anisotropy (FA) in multiple white matter regions. However, these findings vary across studies and between regions. Therefore, in this study, we used tract-based spatial statistics along with machine learning approaches to investigate the whole-brain white matter changes between 17 left mTLE patients and 15 right mTLE patients and 34 matched healthy controls. The results showed that the three groups could be distinguished from each other with promising accuracy. Compared with controls, the FA value of the most discriminating voxels was decreased in the ipsilateral limbic system, corpus callosum, and temporal white matter in both patient groups. Compared with right mTLE, left mTLE had decreased FA in the left temporal white matter, whereas right mTLE had decreased FA in the right frontal and temporal white matter, and right posterior corona radiata. These findings not only provide useful information for lateralization of the seizure focus but can also be used as a potential biomarker for the diagnosis and treatment of the mTLE. This may be helpful in assessment of patients with mTLE when no lesion is detected on visual evaluation. PMID:24918460

An, Jie; Fang, Peng; Wang, Wensheng; Liu, Zhenyin; Hu, Dewen; Qiu, Shijun

2014-07-01

125

Brain white matter microstructure alterations in adolescent rhesus monkeys exposed to early life stress: associations with high cortisol during infancy  

PubMed Central

Background Early adverse experiences, especially those involving disruption of the mother-infant relationship, are detrimental for proper socioemotional development in primates. Humans with histories of childhood maltreatment are at high risk for developing psychopathologies including depression, anxiety, substance abuse, and behavioral disorders. However, the underlying neurodevelopmental alterations are not well understood. Here we used a nonhuman primate animal model of infant maltreatment to study the long-term effects of this early life stress on brain white matter integrity during adolescence, its behavioral correlates, and the relationship with early levels of stress hormones. Methods Diffusion tensor imaging and tract based spatial statistics were used to investigate white matter integrity in 9 maltreated and 10 control animals during adolescence. Basal plasma cortisol levels collected at one month of age (when abuse rates were highest) were correlated with white matter integrity in regions with group differences. Total aggression was also measured and correlated with white matter integrity. Results We found significant reductions in white matter structural integrity (measured as fractional anisotropy) in the corpus callosum, occipital white matter, external medullary lamina, as well as in the brainstem of adolescent rhesus monkeys that experienced maternal infant maltreatment. In most regions showing fractional anisotropy reductions, opposite effects were detected in radial diffusivity, without changes in axial diffusivity, suggesting that the alterations in tract integrity likely involve reduced myelin. Moreover, in most regions showing reduced white matter integrity, this was associated with elevated plasma cortisol levels early in life, which was significantly higher in maltreated than in control infants. Reduced fractional anisotropy in occipital white matter was also associated with increased social aggression. Conclusions These findings highlight the long-term impact of infant maltreatment on brain white matter structural integrity, particularly in tracts involved in visual processing, emotional regulation, and somatosensory and motor integration. They also suggest a relationship between elevations in stress hormones detected in maltreated animals during infancy and long-term brain white matter structural effects.

2013-01-01

126

ADAPTIVE CUTS FOR EXTRACTING SPECIFIC WHITE MATTER TRACTS  

PubMed Central

Extracting specific white matter tracts (e.g., uncinate fasciculus) from whole brain tractography has numerous applications in studying individual differences in white matter. Typically specific tracts are extracted manually, following replicable protocols which can be prohibitively expensive for large scale studies. A tract clustering framework is a suitable computational framework but from a neuroanatomical point of view, one of the key challenges is that it is very hard to design a universal similarity function for different types of white matter tracts (e.g., projection, association, commissural tracts). In this paper, we propose an adaptive cuts framework in which, using normalized cuts motivated objective function, we adaptively learn tract-tract similarity for each specific tract class using atlas based training data. Using the learnt similarity function we train an ensemble of binary support vector machines to extract specific tracts from unlabeled whole-brain tractography sets.

Adluru, Nagesh; Singh, Vikas; Alexander, Andrew L.

2013-01-01

127

Genetic variation in homocysteine metabolism, cognition, and white matter lesions.  

PubMed

Several studies have shown an association between homocysteine concentration and cognitive performance or cerebral white matter lesions. However, variations in genes encoding for enzymes and other proteins that play a role in homocysteine metabolism have hardly been evaluated in relation to these outcome measures. In the population-based Rotterdam Scan Study, we examined the association of seven polymorphisms of genes involved in homocysteine metabolism (MTHFR 677C>T, MTHFR 1298A>C, RFC 80G>A, TC 776C>G, MTR 2756A>G, MTRR 66A>G, and CBS 844ins68) with plasma total homocysteine, cognitive performance, and cerebral white matter lesions among 1011 non-demented elderly participants. Of all the studied polymorphisms, only MTHFR 677C>T was associated with homocysteine concentration. No significant relationship was observed for any of the polymorphisms with cognitive performance or severity of cerebral white matter lesions. PMID:19019492

de Lau, Lonneke M L; van Meurs, Joyce B J; Uitterlinden, André G; Smith, A David; Refsum, Helga; Johnston, Carole; Breteler, Monique M B

2010-11-01

128

White matter abnormalities in pediatric obsessive-compulsive disorder.  

PubMed

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

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

2012-11-01

129

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

130

A structural equation modeling investigation of age-related variance in executive function and DTI measured white matter damage  

Microsoft Academic Search

Cognitive changes in normal aging have been explained by the frontal-executive hypothesis, but the assumptions made by this hypothesis concerning the neurobiological causes are still a matter of debate. Executive functions (EF) may activate neural networks that include disparate grey matter regions, and rely on the integrity of white matter connections. In 118 adults (50–90 years old) from the GENIE

R. A. Charlton; S. Landau; F. Schiavone; T. R. Barrick; C. A. Clark; H. S. Markus; R. G. Morris

2008-01-01

131

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

132

Patterns of White Matter Atrophy in Frontotemporal Lobar Degeneration  

PubMed Central

Background Structural magnetic resonance imaging (MRI) has been used to investigate the in vivo pathology of frontotemporal lobar degeneration. However, few neuroimaging studies have focused on white matter (WM) alterations in this disease. Objectives To use volumetric MRI techniques to identify the patterns of WM atrophy in vivo in 2 clinical variants of frontotemporal lobar degeneration—fronto-temporal dementia (FTD) and semantic dementia—and to compare the patterns of WM atrophy with those of gray matter (GM) atrophy in these diseases. Design Structural MRIs were obtained from patients with FTD (n=12) and semantic dementia (n=13) and in cognitively healthy age-matched controls (n=24). Regional GM and WM were classified automatically from high-resolution T1-, T2-, and proton density-weighted MRIs with Expectation-Maximization Segmentation and compared between the groups using a multivariate analysis of covariance model that included age and WM lesion volumes as covariates. Results Patients with FTD had frontal WM atrophy and frontal, parietal, and temporal GM atrophy compared with controls, who had none. Patients with semantic dementia had temporal WM and GM atrophy and patients with FTD had frontal GM atrophy. Adding temporal WM volume to temporal GM volume significantly improved the discrimination between semantic dementia and FTD. Conclusions These results show that patients with frontotemporal lobar degeneration who are in relatively early stages of the disease (Clinical Dementia Rating score, 1.0-1.2) have WM atrophy that largely parallels the pattern of GM atrophy typically associated with these disorders.

Chao, Linda L.; Schuff, Norbert; Clevenger, Erin M.; Mueller, Susanne G.; Rosen, Howard J.; Gorno-Tempini, Maria L.; Kramer, Joel H.; Miller, Bruce L.; Weiner, Michael W.

2008-01-01

133

Scalable brain network construction on white matter fibers  

NASA Astrophysics Data System (ADS)

DTI offers a unique opportunity to characterize the structural connectivity of the human brain non-invasively by tracing white matter fiber tracts. Whole brain tractography studies routinely generate up to half million tracts per brain, which serves as edges in an extremely large 3D graph with up to half million edges. Currently there is no agreed-upon method for constructing the brain structural network graphs out of large number of white matter tracts. In this paper, we present a scalable iterative framework called the ?-neighbor method for building a network graph and apply it to testing abnormal connectivity in autism.

Chung, Moo K.; Adluru, Nagesh; Dalton, Kim M.; Alexander, Andrew L.; Davidson, Richard J.

2011-03-01

134

Brain white matter lesions in migraine: what's the meaning?  

PubMed

Migraine has been associated with structural brain damage. Several studies have reported an association between migraine and brain white matter lesions or clinically silent infarct-like abnormalities in the posterior circulation territory. The origin of these lesions is still unclear. The cause is commonly interpreted as ischemic, which is consistent with the association of migraine, particularly with aura, with vascular risk factors. The relationship between increased volume of white matter hyperintensities and a history of severe headache per se is under debate. The clinical relevance of this brain damage deserves further investigations even if an association between cognitive impairment and migraine or headache of any type is not confirmed. PMID:21533710

Colombo, Bruno; Dalla Libera, D; Comi, G

2011-05-01

135

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

136

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

137

COMT genotype affects prefrontal white matter pathways in children and adolescents  

PubMed Central

Diffusion tensor imaging is widely used to evaluate the development of white matter. Information about how alterations in major neurotransmitter systems, such as the dopamine (DA) system, influence this development in healthy children, however, is lacking. Catechol-O-metyltransferase (COMT) is the major enzyme responsible for DA degradation in prefrontal brain structures, for which there is a corresponding genetic polymorphism (val158met) that confers either a more or less efficient version of this enzyme. The result of this common genetic variation is that children may have more or less available synaptic DA in prefrontal brain regions. In the present study we examined the relation between diffusion properties of frontal white matter structures and the COMT val158met polymorphism in 40 children ages 9–15. We found that the val allele was associated with significantly elevated fractional anisotropy values and reduced axial and radial diffusivities. These results indicate that the development of white matter in healthy children is related to COMT genotype and that alterations in white matter may be related to the differential availability of prefrontal DA. This investigation paves the way for further studies of how common functional variants in the genome might influence the development of brain white matter.

Thomason, Moriah E.; Dougherty, Robert F.; Colich, Natalie L.; Perry, Lee M.; Rykhlevskaia, Elena I.; Louro, Hugo M.; Hallmayer, Joachim F.; Waugh, Christian E.; Bammer, Roland; Glover, Gary H.; Gotlib, Ian H.

2010-01-01

138

Reversible Confluent Deep White Matter Abnormalities: A New Variant of Posterior Reversible Encephalopathy Syndrome  

PubMed Central

We describe a confluent deep white matter abnormalities variant of PRES, further strengthening the notion that PRES is a disorder of radiological heterogeneity. We present 2 cases of PRES with findings of diffuse but reversible vasogenic edema located in the deep periventricular white matter regions of bilateral hemispheres without a clearly posterior distribution. We feel that this represents a rare variant of PRES on imaging, thus adding to the existing radiological spectrum for this entity. Both of our patients presented with malignant hypertension (mean arterial blood pressure of 200?mmHg) and developed neurological symptoms that included encephalopathy, seizure, headache, and vision changes. Additionally, both patients presented with significant subcortical white matter edema that improved dramatically on follow-up imaging. The clinical and radiological improvement in both patients occurred following successful blood pressure management. It is possible that the deep white matter changes of PRES are seen exclusively in the setting of severe accelerated hypertension. Our case reports reveal that, in patients with hypertensive encephalopathy, a deep white matter pattern of diffuse signal changes may not necessarily indicate chronic ischemic changes and follow-up imaging studies are essential to rule out a diagnosis of PRES.

Li, Yuebing; Castaldo, John; Bemporad, Joshua; Yacoub, Hussam A.

2013-01-01

139

Local termination pattern analysis: a tool for comparing white matter morphology.  

PubMed

Disconnections between structures in the brain have long been hypothesized to be the mechanism behind numerous disease states and pathological behavioral phenotypes. Advances in diffusion weighted imaging (DWI) provide an opportunity to study white matter, and therefore brain connectivity, in great detail. DWI-based research assesses white matter at two different scales: voxelwise indexes of anisotropy such as fractional anisotropy (FA) are used to compare small units of tissue and network-based methods compare tractography-based models of whole-brain connectivity. We propose a method called local termination pattern analysis (LTPA) that considers information about both local and global brain connectivity simultaneously. LTPA itemizes the subset of streamlines that pass through a small set of white matter voxels. The "local termination pattern" is a vector defined by counts of these streamlines terminating in pairs of cortical regions. To assess the reliability of our method we applied LTPA exhaustively over white matter voxels to produce complete maps of local termination pattern similarity, based on diffusion spectrum imaging (DSI) data from 11 individuals in triplicate. Here we show that local termination patterns from an individual are highly reproducible across the entire brain. We discuss how LTPA can be deployed into a clinical database and used to characterize white matter morphology differences due to disease, developmental or genetic factors. PMID:23999931

Cieslak, M; Grafton, S T

2014-06-01

140

Microstructural white matter changes are correlated with the stage of psychiatric illness  

PubMed Central

Microstructural white matter changes have been reported in the brains of patients across a range of psychiatric disorders. Evidence now demonstrates significant overlap in these regions in patients with affective and psychotic disorders, thus raising the possibility that these conditions share common neurobiological processes. If affective and psychotic disorders share these disruptions, it is unclear whether they occur early in the course or develop gradually with persistence or recurrence of illness. Utilisation of a clinical staging model, as an adjunct to traditional diagnostic practice, is a viable mechanism for measuring illness progression. It is particularly relevant in young people presenting early in their illness course. It also provides a suitable framework for determining the timing of emergent brain alterations, including disruptions of white matter tracts. Using diffusion tensor imaging, we investigated the integrity of white matter tracts in 74 patients with sub-syndromal psychiatric symptoms as well as in 69 patients diagnosed with established psychosis or affective disorder and contrasted these findings with those of 39 healthy controls. A significant disruption in white matter integrity was found in the left anterior corona radiata and in particular the anterior thalamic radiation for both the patients groups when separately contrasted with healthy controls. Our results suggest that patients with sub-syndromal symptoms exhibit discernable early white matter changes when compared with healthy control subjects and more significant disruptions are associated with clinical evidence of illness progression.

Lagopoulos, J; Hermens, D F; Hatton, S N; Battisti, R A; Tobias-Webb, J; White, D; Naismith, S L; Scott, E M; Ryder, W J; Bennett, M R; Hickie, I B

2013-01-01

141

Accumulation of oedema fluid in deep white matter after cerebral cold injury.  

PubMed

The distribution of oedema fluid was examined in cats subjected to a cryogenic cortical injury. The lesion was made in the parietal cortex, and the animals were sacrificed 6 hr after the injury. The serum concentration of 125I bovine serum albumin was kept constant over the 6 hr period by a programmed infusion. Autoradiograms were made from the coronal sections through the lesion and were used to quantify densitometrically the regional content of extravasated serum albumin. After autoradiographic exposure, the section was stained with luxol-fast blue (LFB), and the degree of LFB discoloration was quantified. The maximal accumulation of extravasated serum albumin was observed in the deeper white matter under the subcortical white matter and not in the subcortical white matter of the lesion. The degree of oedema indicated by LFB discoloration showed a similar distribution pattern. This indicates that the compliance of the white matter in vasogenic oedema is regionally different. This difference of regional compliance seems to depend on the structural characteristics of each region such as the type of the fibers and the orientation of the fibers. PMID:2089962

Kuroiwa, T; Yokofujita, J; Kaneko, H; Okeda, R

1990-01-01

142

Magnetisation transfer ratio of normal brain white matter: a normative database spanning four decades of life  

Microsoft Academic Search

OBJECTIVES: To establish a normative database for magnetisation transfer ratio (MTR) measurements in the white matter of healthy adult brains. Such MTR values were evaluated for regional variation and evidence of differences associated with aging, sex, and handedness. METHODS: Forty one healthy volunteers, ranging in age from 16 to 55 years, underwent axial brain magnetisation transfer (MT) imaging on a

N C Silver; G J Barker; D G MacManus; P S Tofts; D H Miller

1997-01-01

143

From diffusion tractography to quantitative white matter tract measures: a reproducibility study  

Microsoft Academic Search

The aim of this study is to propose methods for assessing the reproducibility of diffusion tractography algorithms in future clinical studies and to show their application to the tractography algorithm developed in our unit, fast marching tractography (FMT). FMT estimates anatomical connectivity between brain regions using the information provided by diffusion tensor imaging. Three major white-matter pathways were investigated in

O. Ciccarelli; G. J. M. Parker; A. T. Toosy; C. A. M. Wheeler-Kingshott; G. J. Barker; P. A. Boulby; D. H. Miller; A. J. Thompson

2003-01-01

144

Microstructural correlations of white matter tracts in the human brain  

Microsoft Academic Search

The purpose of this study is to investigate whether specific patterns of correlation exist in diffusion tensor imaging (DTI) parameters across different white matter tracts in the normal human brain, and whether the relative strengths of these putative microstructural correlations might reflect phylogenetic and functional similarities between tracts. We performed quantitative DTI fiber tracking on 44 healthy adult volunteers to

Michael Wahl; Yi-Ou Li; Joshua Ng; Sara C. LaHue; Shelly R. Cooper; Elliott H. Sherr; Pratik Mukherjee

2010-01-01

145

Disappearance of a white matter lesion in incontinentia pigmenti  

Microsoft Academic Search

We report a 12-month-old Japanese female with incontinentia pigmenti, in whom magnetic resonance imaging (MRI) disclosed a small transient lesion in the white matter. After birth, she developed some vesicular skin eruptions that mainly involved the lower extremities. These skin lesions increased in size and number and became hyperpigmented within 2 weeks. At 1 month of age, MRI revealed a

Hideto Yoshikawa; Yumiko Uehara; Tokinari Abe; Yoshihiko Oda

2000-01-01

146

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

147

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

148

1049. Regenerative Cell Therapy for White Matter Disorders  

Microsoft Academic Search

We tested the therapeutic potential of neurospheres generated from GFP transgenic rats as regenerative therapy for white matter diseases. We previously reported that postnatal derived rat neurospheres generate more than 50% oligodendrocytes in vitro. GFP+ postnatal neurospheres were transplanted into the corpus callosum of chemically induced demyelination rat model and in a Canavan rat model (Tremor rat caused by a

Ana Olariu; Jeremy Francis; Scott McPhee; Eiji Kobayashi; Paola Leone

2006-01-01

149

Connecting cerebral white matter lesions and hypertensive target organ damage.  

PubMed

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. PMID:21837275

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

2011-01-01

150

Cerebral White Matter Hyperintensities Predict Functional Stroke Outcome  

Microsoft Academic Search

Background: Growing evidence suggests that white matter hyperintensities (WMHs) are implicated in stroke recurrence and mortality, and their location can be a critical factor. This study evaluated the impact of periventricular WMHs (PVWMHs) and subcortical WMHs (SWMHs) on poststroke functional outcomes. Methods: Brain MRI was performed on 187 acute ischemic stroke patients (57.8% male; mean age = 64.3 years) recruited

Li-Min Liou; Chien-Fu Chen; Yuh-Cherng Guo; Hsiu-Ling Cheng; Hui-Lin Lee; Jui-Sheng Hsu; Ruey-Tay Lin; Hsiu-Fen Lin

2010-01-01

151

Impaired cerebrovascular hemodynamics are associated with cerebral white matter damage.  

PubMed

White matter hyperintensities (WMH) in elderly individuals with vascular diseases are presumed to be due to ischemic small vessel diseases; however, their etiology is unknown. We examined the cross-sectional relationship between cerebrovascular hemodynamics and white matter structural integrity in elderly individuals with vascular risk factors. White matter hyperintensity volumes, fractional anisotropy (FA), and mean diffusivity (MD) were obtained from MRI in 48 subjects (75±7years). Pulsatility index (PI) and dynamic cerebral autoregulation (dCA) was assessed using transcranial Doppler ultrasound of the middle cerebral artery. Dynamic cerebral autoregulation was calculated from transfer function analysis (phase and gain) of spontaneous blood pressure and flow velocity oscillations in the low (LF, 0.03 to 0.15?Hz) and high (HF, 0.16 to 0.5?Hz) frequency ranges. Higher PI was associated with greater WMH (P<0.005). Higher phase across all frequency ranges was associated with greater FA and lower MD (P<0.005). Lower gain was associated with higher FA in the LF range (P=0.001). These relationships between phase and FA were significant in the territories limited to the middle cerebral artery as well as across the entire brain. Our results show a strong relationship between impaired cerebrovascular hemodynamics (PI and dCA) and loss of cerebral white matter structural integrity (WMH and DTI metrics) in elderly individuals. PMID:24129749

Purkayastha, Sushmita; Fadar, Otite; Mehregan, Aujan; Salat, David H; Moscufo, Nicola; Meier, Dominik S; Guttmann, Charles Rg; Fisher, Naomi Dl; Lipsitz, Lewis A; Sorond, Farzaneh A

2014-02-01

152

Cigarette smoking and white matter microstructure in schizophrenia  

Microsoft Academic Search

The majority of patients with schizophrenia smoke cigarettes. Both nicotine use and schizophrenia have been associated with alterations in brain white matter microstructure as measured by diffusion tensor imaging (DTI). The purpose of this study was to examine fractional anisotropy (FA) in smoking and non-smoking patients with schizophrenia and in healthy volunteers. A total of 43 patients (28 smoking and

Kathryn R. Cullen; Stuart Wallace; Vincent A. Magnotta; Jeremy Bockholt; Stephan Erlich; Randy L. Gollub; Dara S. Manoach; Beng C. Ho; Vincent P. Clark; John Lauriello; Juan R. Bustillo; S. Charles Schulz; Nancy C. Andreasen; Vince D. Calhoun; Kelvin O. Lim; Tonya White

153

Regularized Stochastic White Matter Tractography Using Diffusion Tensor MRI  

Microsoft Academic Search

The development of Diffusion Tensor MRI has raised hopes in the neuro-science community for in vivo methods to track fiber paths in the white matter. A number of approaches have been presented, but there are still several essential problems that need to be solved. In this paper a novel fiber propagation model is proposed, based on stochastics and regularization, allowing

Mats Björnemo; Anders Brun; Ron Kikinis; Carl-fredrik Westin

2002-01-01

154

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

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

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

2013-01-01

157

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

158

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

2012-01-01

159

White Matter Abnormalities in Veterans With Mild Traumatic Brain Injury  

PubMed Central

Objective It has been estimated that 10%–20% of U.S. veterans of the wars in Iraq and Afghanistan experienced mild traumatic brain injury (TBI), mostly secondary to blast exposure. Diffusion tensor imaging (DTI) may detect subtle white matter changes in both the acute and chronic stages of mild TBI and thus has the potential to detect white matter damage in patients with TBI. The authors used DTI to examine white matter integrity in a relatively large group of veterans with a history of mild TBI. Method DTI images from 72 veterans of the wars in Iraq and Afghanistan who had mild TBI were compared with DTI images from 21 veterans with no exposure to TBI during deployment. Conventional voxel-based analysis as well as a method of identifying spatially heterogeneous areas of decreased fractional anisotropy (“potholes”) were used. Veterans also underwent psychiatric and neuropsychological assessments. Results Voxel-based analysis did not reveal differences in DTI parameters between the veterans with mild TBI and those with no TBI. However, the veterans with mild TBI had a significantly higher number of potholes than those without TBI. The difference in the number of potholes was not influenced by age, time since trauma, a history of mild TBI unrelated to deployment, or coexisting psychopathology. The number of potholes was correlated with the severity of TBI and with performance in executive functioning tasks. Conclusions Veterans who had blast-related mild TBI showed evidence of multifocal white matter abnormalities that were associated with severity of the injury and with relevant functional measures. Overall, white matter potholes may constitute a sensitive biomarker of axonal injury that can be identified in mild TBI at acute and chronic stages of its clinical course.

Jorge, Ricardo E.; Acion, Laura; White, Tonya; Tordesillas-Gutierrez, Diana; Pierson, Ronald; Crespo-Facorro, Benedicto; Magnotta, Vincent A.

2014-01-01

160

White matter alterations in temporal lobe epilepsy  

NASA Astrophysics Data System (ADS)

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

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

2011-03-01

161

Spatial Patterns of Whole Brain Grey and White Matter Injury in Patients with Occult Spastic Diplegic Cerebral Palsy  

PubMed Central

Spastic diplegic cerebral palsy(SDCP)is a common type of cerebral palsy (CP), which presents as a group of motor-impairment syndromes. Previous conventional MRI studies have reported abnormal structural changes in SDCP, such as periventricular leucomalacia. However, there are roughly 27.8% SDCP patients presenting normal appearance in conventional MRI, which were considered as occult SDCP. In this study, sixteen patients with occult SDCP and 16 age- and sex-matched healthy control subjects were collected and the data were acquired on a 3T MR system. We applied voxel-based morphometry (VBM) and tract-based spatial statistics (TBSS) analysis to investigate whole brain grey and white matter injury in occult SDCP. By using VBM method, the grey matter volume reduction was revealed in the bilateral basal ganglia regions, thalamus, insula, and left cerebral peduncle, whereas the white matter atrophy was found to be located in the posterior part of corpus callosum and right posterior corona radiata in the occult SDCP patients. By using TBSS, reduced fractional anisotropy (FA) values were detected in multiple white matter regions, including bilateral white matter tracts in prefrontal lobe, temporal lobe, internal and external capsule, corpus callosum, cingulum, thalamus, brainstem and cerebellum. Additionally, several regions of white matter tracts injury were found to be significantly correlated with motor dysfunction. These results collectively revealed the spatial patterns of whole brain grey and white matter injury in occult SDCP.

Wang, Hong; Duan, Shaofeng; Zhang, Zan; Dai, Guanghui; Ma, Qiaozhi; Shan, Baoci; Ma, Lin

2014-01-01

162

Spatial patterns of whole brain grey and white matter injury in patients with occult spastic diplegic cerebral palsy.  

PubMed

Spastic diplegic cerebral palsy(SDCP)is a common type of cerebral palsy (CP), which presents as a group of motor-impairment syndromes. Previous conventional MRI studies have reported abnormal structural changes in SDCP, such as periventricular leucomalacia. However, there are roughly 27.8% SDCP patients presenting normal appearance in conventional MRI, which were considered as occult SDCP. In this study, sixteen patients with occult SDCP and 16 age- and sex-matched healthy control subjects were collected and the data were acquired on a 3T MR system. We applied voxel-based morphometry (VBM) and tract-based spatial statistics (TBSS) analysis to investigate whole brain grey and white matter injury in occult SDCP. By using VBM method, the grey matter volume reduction was revealed in the bilateral basal ganglia regions, thalamus, insula, and left cerebral peduncle, whereas the white matter atrophy was found to be located in the posterior part of corpus callosum and right posterior corona radiata in the occult SDCP patients. By using TBSS, reduced fractional anisotropy (FA) values were detected in multiple white matter regions, including bilateral white matter tracts in prefrontal lobe, temporal lobe, internal and external capsule, corpus callosum, cingulum, thalamus, brainstem and cerebellum. Additionally, several regions of white matter tracts injury were found to be significantly correlated with motor dysfunction. These results collectively revealed the spatial patterns of whole brain grey and white matter injury in occult SDCP. PMID:24964139

Mu, Xuetao; Nie, Binbin; Wang, Hong; Duan, Shaofeng; Zhang, Zan; Dai, Guanghui; Ma, Qiaozhi; Shan, Baoci; Ma, Lin

2014-01-01

163

Brain white matter tractography based on Riemannian manifold  

NASA Astrophysics Data System (ADS)

Diffusion tensor imaging (DTI) is the only noninvasive technique of analyzing and qualifying water molecule's diffusion anisotropy in brain tissues. This paper presented a novel algorithm to analyze DTI and brain white matter tractography based on Riemannian manifold. Firstly, a 3×3 symmetric positive definite covariant tensor was constructed for each voxel using DTI, so brain white matte can be represented as a tensor field. Secondly, the tensor field was regarded as Riemannian manifold, and the fluid motion in the tensor field was represented by Navier-Stoke equation, so the problem of brain white matter tractography between two voxels can be transformed into the computation of smallest distance between two points in Riemannian manifold. Finally, distances between two points in Riemannian manifold can be represented by geodesic, and the numerical solution was based on Level-Set method, which was the brain white matter tractography. In experiment, this paper compared our method and the traditional algorithm based on a digital DTI phantom. The experiment result showed that our method could accurately retrieve the DTI tractography, and was more robust than traditional algorithm.

Meng, Lu; Liu, Bin; Zhao, Hong; Zhao, Dazhe

2010-08-01

164

Early gray-matter and white-matter concentration in infancy predict later language skills: A whole brain voxel-based morphometry study  

PubMed Central

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. Early gray-matter concentration in the right cerebellum, early white-matter concentration in the right cerebellum, and early white-matter concentration in the left posterior limb of the internal capsule (PLIC)/cerebral peduncle were positively and strongly associated with infants’ receptive language ability at 12 months. Early gray-matter concentration in the right hippocampus was positively and strongly correlated with infants’ expressive language ability at 12 months. Our results suggest that the cerebellum, PLIC/cerebral peduncle, and the hippocampus may be associated with early language development. Potential links between these structural predictors and infants’ linguistic functions are discussed.

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

2012-01-01

165

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

2013-01-01

166

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

167

Decreased frontal white-matter integrity in abstinent methamphetamine abusers.  

PubMed

This study explored differences in frontal white-matter (WM) integrity between methamphetamine (MA) abusers and healthy comparison subjects using diffusion tensor imaging (DTI). Fractional anisotropy (FA) values, which indicate WM integrity, were calculated for regions-of-interest in frontal WM on diffusion tensor images of 32 MA abusers and 30 healthy comparison subjects. Frontal executive functions were also assessed by the Wisconsin Card Sorting test (WCST). MA abusers had significantly lower FA values in bilateral frontal WM at the anterior commissure-posterior commissure (AC-PC) plane and the right frontal WM 5 mm above the AC-PC plane relative to healthy comparison subjects. MA abusers had more total, perseveration and non-perseveration errors in the WCST relative to healthy comparison subjects. FA values of the right frontal WM 5 mm above the AC-PC plane negatively correlated with the number of total and non-perseveration errors in the WCST in MA abusers. In the sub-analysis for gender differences, lower FA values in frontal WM and more errors in the WCST were found only in male MA abusers, not in female MA abusers, relative to comparison subjects of the respective gender. We report that frontal WM integrity of MA abusers is compromised. This finding may also be related to impairment in frontal executive function. In addition, the neurotoxic effect of MA on frontal WM may be less prominent in women than in men, possibly due to oestrogen's neuroprotective effect. PMID:17147837

Chung, Ain; Lyoo, In Kyoon; Kim, Seog Ju; Hwang, Jaeuk; Bae, Soojeong C; Sung, Young Hoon; Sim, Minyoung E; Song, In Chan; Kim, Jihyun; Chang, Kee Hyun; Renshaw, Perry F

2007-12-01

168

White Matter Hyperintensities in Mild Lewy Body Dementia  

PubMed Central

Background The objective of this study was to explore the load of white matter hyperintensities (WMH) in patients with Lewy body dementia (LBD) and compare to Alzheimer's disease (AD) and normal controls (NC). Methods Diagnosis of LBD and AD was made according to consensus criteria and cognitive tests were administered. MRI scans for 77 (61 AD and 16 LBD) patients and 37 healthy elderly control subjects were available for analysis. We segmented WMH from FLAIR images using an automatic thresholding technique and calculated the volume of WMH in several regions of the brain, using non-parametric tests to compare groups. Multivariate regression was applied. Results There were no significant differences in WMH between AD and LBD. We found a significant correlation between total and frontal WMH and Mini-Mental State Examination (MMSE) and verbal fluency scores in the AD group, but not in the LBD group. Conclusion The WMH load in LBD was similar to that of AD. A correlation between WMH load and cognition was found in the AD group, but not in the LBD group, suggesting that vascular disease contributes to cognitive impairment in AD but not LBD.

Oppedal, K.; Aarsland, D.; Firbank, M.J.; Sonnesyn, H.; Tysnes, O.B.; O'Brien, J.T.; Beyer, M.K.

2012-01-01

169

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

170

White Matter Tract Damage in the Behavioral Variant of Frontotemporal and Corticobasal Dementia Syndromes  

PubMed Central

The phenotypes of the behavioral variant of frontotemporal dementia and the corticobasal syndrome present considerable clinical and anatomical overlap. The respective patterns of white matter damage in these syndromes have not been directly contrasted. Beyond cortical involvement, damage to white matter pathways may critically contribute to both common and specific symptoms in both conditions. Here we assessed patients with the behavioral variant of frontotemporal dementia and corticobasal syndrome with whole-brain diffusion tensor imaging to identify the white matter networks underlying these pathologies. Twenty patients with the behavioral variant of frontotemporal dementia, 19 with corticobasal syndrome, and 15 healthy controls were enrolled in the study. Differences in tract integrity between (i) patients and controls, and (ii) patients with the corticobasal syndrome and the behavioral variant of frontotemporal dementia were assessed with whole brain tract-based spatial statistics and analyses of regions of interest. Behavioral variant of frontotemporal dementia and the corticobasal syndrome shared a pattern of bilaterally decreased white matter integrity in the anterior commissure, genu and body of the corpus callosum, corona radiata and in the long intrahemispheric association pathways. Patients with the behavioral variant of frontotemporal dementia showed greater damage to the uncinate fasciculus, genu of corpus callosum and forceps minor. In contrast, corticobasal syndrome patients had greater damage to the midbody of the corpus callosum and perirolandic corona radiata. Whereas several compact white matter pathways were damaged in both the behavioral variant of frontotemporal dementia and corticobasal syndrome, the distribution and degree of white matter damage differed between them. These findings concur with the distinctive clinical manifestations of these conditions and may improve the in vivo neuroanatomical and diagnostic characterization of these disorders.

Tovar-Moll, Fernanda; de Oliveira-Souza, Ricardo; Bramati, Ivanei Edson; Zahn, Roland; Cavanagh, Alyson; Tierney, Michael; Moll, Jorge; Grafman, Jordan

2014-01-01

171

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

PubMed

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

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

2010-01-01

172

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

PubMed Central

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

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

2010-01-01

173

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

PubMed Central

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 CR 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.

Bendlin, B.B.; Canu, E.; Willette, A.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.

2010-01-01

174

Individual differences in white matter anatomy predict dissociable components of reading skill in adults.  

PubMed

We used diffusion tensor imaging (DTI) to investigate relationships between white matter anatomy and different reading subskills in typical-reading adults. A series of analytic approaches revealed that phonological decoding ability is associated with anatomical markers that do not relate to other reading-related cognitive abilities. Thus, individual differences in phonological decoding might relate to connectivity between a network of cortical regions, while skills like sight word reading might rely less strongly on integration across regions. Specifically, manually-drawn ROIs and probabilistic tractography revealed an association between the volume and integrity of white matter underlying primary auditory cortex and nonword reading ability. In a related finding, more extensive cross-hemispheric connections through the isthmus of the corpus callosum predicted better phonological decoding. Atlas-based white matter ROIs demonstrated that relationships with nonword reading were strongest in the inferior fronto-occipital fasciculus and uncinate fasciculus that connect occipital and anterior temporal cortex with inferior frontal cortex. In contrast, tract volume underlying the left angular gyrus was related to nonverbal IQ. Finally, connectivity underlying functional ROIs that are differentially active during phonological and semantic processing predicted nonword reading and reading comprehension, respectively. Together, these results provide important insights into how white matter anatomy may relate to both typical reading subskills, and perhaps a roadmap for understanding neural connectivity in individuals with reading impairments. PMID:24704456

Welcome, Suzanne E; Joanisse, Marc F

2014-08-01

175

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

PubMed

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

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

2014-09-01

176

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

177

Intracellular calcium-binding protein S100A4 influences injury-induced migration of white matter astrocytes  

Microsoft Academic Search

Astrocytes play a crucial role in central nervous system (CNS) pathophysiology. White and gray matter astrocytes are regionally\\u000a specialized, and likely to respond differently to CNS injury and in CNS disease. We previously showed that the calcium-binding\\u000a protein S100A4 is exclusively expressed in white matter astrocytes and markedly up-regulated after injury. Furthermore, down-regulation\\u000a of S100A4 in vitro significantly increases the

Z. Fang; N. Duthoit; G. Wicher; Ö. Källskog; N. Ambartsumian; E. Lukanidin; K. Takenaga; E. N. Kozlova

2006-01-01

178

White matter impairment in chronic heroin dependence: a quantitative DTI study.  

PubMed

Exposure to addictive drugs has been associated with disrupted brain white matter integrity. A few studies have examined the white matter deficits in heroin users; however, the results were influenced by the use of substitution drugs such as methadone and buprenorphine. The present study assessed the alteration in white matter integrity and heroin-related neuropathology in heroin dependents who had not received any replacement therapy using quantitative diffusion tensor imaging (DTI). The study comprised 17 heroin-dependent (HD) subjects and 15 matched healthy controls (HC). Fractional anisotropy (FA) and eigenvalues (??, ?||) of white matter in the whole brain were measured and compared using a voxel-based analysis. The correlation between DTI measurements in identified regions and history of heroin exposure was tested by partial correlation analysis. Compared with HCs, HD subjects displayed decreased FA in the bilateral frontal lobe sub-gyrus, cingulate gyrus, medial frontal gyrus, extra-nuclear, left temporal lobe sub-gyrus and right superior frontal gyrus. Among these regions, the HD group had significantly increased ?? in the bilateral frontal lobe sub-gyrus, cingulate gyrus and extra-nuclear relative to the HC group. There were no group differences in ?||. In addition, there were no significant correlations between duration of heroin use or accumulated dosage and FA or ?? values. In conclusion, chronic heroin-dependent subjects had widespread disruption of white matter structural connectivity located mainly in anterior and superior regions of the brain. Damage to myelin other than axons was the primary pathological feature in the brain of the heroin user. PMID:23895765

Li, Wei; Li, Qiang; Zhu, Jia; Qin, Yue; Zheng, Ying; Chang, Haifeng; Zhang, Dongsheng; Wang, Hanyue; Wang, Lina; Wang, Yarong; Wang, Wei

2013-09-19

179

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

2009-01-01

180

Localization of white matter volume increase in autism and developmental language disorder  

Microsoft Academic Search

Increased brain volume in autism appears to be driven mainly by an unexplained white matter enlargement, and we have reported a similar phenomenon in developmental language disorder (DLD). Localization of this enlargement would strongly guide research into its cause, tissue basis, and functional implications. We utilized a white matter parcellation technique that divides cerebral white matter into an outer zone

Martha R. Herbert; David A. Ziegler; Nikos Makris; Pauline A. Filipek; Thomas L. Kemper; Joseph J. Normandin; Heather A. Sanders; David N. Kennedy; Verne S. Caviness Jr

2004-01-01

181

Characterization of displaced white matter by brain tumors using combined DTI and fMRI  

Microsoft Academic Search

In vivo white matter tractography by diffusion tensor imaging (DTI) has become a popular tool for investigation of white matter architecture in the normal brain. Despite some unresolved issues regarding the accuracy of DTI, recent studies applied DTI for delineating white matter organization in the vicinity of brain lesions and especially brain tumors. Apart from the intrinsic limitations of DTI,

Tom Schonberg; Pazit Pianka; Talma Hendler; Ofer Pasternak; Yaniv Assaf

2006-01-01

182

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

Microsoft Academic Search

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

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

2010-01-01

183

Chronic Kidney Disease Is Associated With White Matter Hyperintensity Volume The Northern Manhattan Study (NOMAS)  

Microsoft Academic Search

Background and Purpose—White matter hyperintensities have been associated with increased risk of stroke, cognitive decline, and dementia. Chronic kidney disease is a risk factor for vascular disease and has been associated with inflammation and endothelial dysfunction, which have been implicated in the pathogenesis of white matter hyperintensities. Few studies have explored the relationship between chronic kidney disease and white matter

Minesh Khatri; Clinton B. Wright; Thomas L. Nickolas; Myunghee C. Paik; Grace Kranwinkel; Ralph L. Sacco; Charles DeCarli

184

Cognitive Correlates of White Matter Growth and Stress Hormones in Female Squirrel Monkey Adults  

Microsoft Academic Search

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

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

2004-01-01

185

Automatic Tractography Segmentation Using a High-Dimensional White Matter Atlas  

Microsoft Academic Search

We propose a new white matter atlas creation method that learns a model of the common white matter structures present in a group of subjects. We demonstrate that our atlas creation method, which is based on group spectral clustering of tractography, discovers structures corresponding to expected white matter anatomy such as the corpus callosum, uncinate fasciculus, cingulum bundles, arcuate fasciculus,

Lauren J. O'Donnell; Carl-fredrik Westin

2007-01-01

186

An error analysis of white matter tractography methods: synthetic diffusion tensor field simulations  

Microsoft Academic Search

White matter tractography using diffusion tensor MR images is a promising method for estimating the pathways of white matter tracts in the human brain. The success of this method ultimately depends upon the accuracy of the white matter tractography algorithms. In this study, a Monte Carlo simulation was used to investigate the impact of SNR, tensor anisotropy, and diffusion tensor

Mariana Lazar; Andrew L. Alexander

2003-01-01

187

Quantitative analysis of gray- and white-matter volumes and glucose metabolism in Sturge-Weber syndrome.  

PubMed

The progressive nature of Sturge-Weber syndrome is well known, but the mechanisms of focal cortical and subcortical degeneration in this disorder are poorly understood. In the present study, we assessed the structural and functional integrity of gray and white matter in unihemispheric Sturge-Weber syndrome using quantitative magnetic resonance imaging (MRI) volumetry and MRI-based partial volume correction of [18F]fluorodeoxyglucose positron emission tomographic (PET) images. Gray- and white-matter volumes and glucose metabolism were measured in three brain regions (parieto-occipital underneath the angioma, temporal, and frontal) in six children with Sturge-Weber syndrome (two infants, ages 6 and 9 months; four older children, ages 4 to 14 years), all with unilateral parieto-occipital leptomeningeal angiomatosis. The gray-matter volumes ipsilateral to the angioma were smaller in all children, with the posterior regions underneath the angioma the most affected. In the infants, the white-matter volumes were increased in the region of the angioma, whereas in the regions remote from the angioma in the infants and in all regions of the older children, there were large decreases in white-matter volume. The decreases of frontal and temporal white-matter volume were more pronounced than the corresponding gray-matter volume decreases. The PET studies showed severe hypometabolism in the parieto-occipitalregion underneath the angioma in all of the children. However, the two infants showed glucose hypermetabolism in the frontal and temporal cortical gray matter, whereas these regions had relatively preserved metabolism in the older patients. These results demonstrate differential involvement of gray and white matter in Sturge-Weber syndrome. Both structural and functional abnormalities extend well beyond the angioma, indicating widespread abnormalities of growth and development of the affected hemisphere. Furthermore, whereas increased white-matter volume underlying the angioma may be seen in infants, ipsilateral white-matter regions outside the angioma show volume loss both in infants and in older patients. Extensive gray- and white-matter volume loss and hypometabolism ipsilateral to the angioma likely contribute to the frequently observed progressive cognitive dysfunction in these patients, regardless of the extent of the angioma. PMID:12693779

Pfund, Zoltán; Kagawa, Kenji; Juhász, Csaba; Shen, Chenggang; Lee, Joon Soo; Chugani, Diane C; Muzik, Otto; Chugani, Harry T

2003-02-01

188

Differential Developmental Trajectories of Magnetic Susceptibility in Human Brain Gray and White Matter Over the Lifespan  

PubMed Central

As indicated by several recent studies, magnetic susceptibility of the brain is influenced mainly by myelin in the white matter and by iron deposits in the deep nuclei. Myelination and iron deposition in the brain evolve both spatially and temporally. This evolution reflects an important characteristic of normal brain development and ageing. In this study, we assessed the changes of regional susceptibility in the human brain in vivo by examining the developmental and ageing process from 1 to 83 years of age. The evolution of magnetic susceptibility over this lifespan was found to display differential trajectories between the gray and the white matter. In both cortical and subcortical white matter, an initial decrease followed by a subsequent increase in magnetic susceptibility was observed, which could be fitted by a Poisson curve. In the gray matter, including the cortical gray matter and the iron-rich deep nuclei, magnetic susceptibility displayed a monotonic increase that can be described by an exponential growth. The rate of change varied according to functional and anatomical regions of the brain. For the brain nuclei, the age-related changes of susceptibility were in good agreement with the findings from R2* measurement. Our results suggest that magnetic susceptibility may provide valuable information regarding the spatial and temporal patterns of brain myelination and iron deposition during brain maturation and ageing.

Li, Wei; Wu, Bing; Batrachenko, Anastasia; Bancroft-Wu, Vivian; Morey, Rajendra A.; Shashi, Vandana; Langkammer, Christian; De Bellis, Michael D.; Ropele, Stefan; Song, Allen W.; Liu, Chunlei

2014-01-01

189

Astrocytic Hypertrophy in Anterior Cingulate White Matter of Depressed Suicides  

Microsoft Academic Search

Increasing evidence suggests that cortical astrocytic function is disrupted in mood disorders and suicide. The fine neuroanatomy of astrocytes, however, remains to be investigated in these psychiatric conditions. In this study, we performed a detailed morphometric analysis of 3D-reconstructed gray and white matter astrocytes in Golgi-impregnated anterior cingulate cortex (ACC) samples from depressed suicides and matched controls. Postmortem ACC samples

Susana G Torres-Platas; Christa Hercher; Maria Antonietta Davoli; Gilles Maussion; Benoit Labonté; Gustavo Turecki; Naguib Mechawar

2011-01-01

190

Toluene abuse and white matter: a model of toxic leukoencephalopathy.  

PubMed

The brain is the primary target of toluene (methylbenzene), the major solvent in spray paint and a constituent of many other easily obtained commercial and industrial products. The effects of acute intoxication can be dramatic and the lasting adverse effects of inhalants may be highly injurious. Mental status alterations range from acute confusional state to coma. Toluene abuse effects on white matter are demonstrable neuroradiologically and neuropathologically, and have important neurobehavioral consequences. PMID:23688693

Filley, Christopher M

2013-06-01

191

Structural gray and white matter changes in patients with HIV  

Microsoft Academic Search

In this cross-sectional study we used magnetic resonance imaging (MRI)-based voxel based morphometry (VBM) in a sample of\\u000a HIV positive patients to detect structural gray and white matter changes. Forty-eight HIV positive subjects with (n = 28) or without (n = 20) cognitive deficits (mean age 48.5 ± 9.6 years) and 48 age- and sex-matched HIV negative controls underwent MRI for\\u000a VBM analyses. Clinical testing in HIV

Michael KuperK; K. Rabe; S. Esser; E. R. Gizewski; I. W. Husstedt; M. Maschke; M. Obermann

2011-01-01

192

Distributed grey and white matter deficits in hyperkinetic disorder: MRI evidence for anatomical abnormality in an attentional network  

Microsoft Academic Search

Background. Previous neuroimaging studies of children with attention deficit hyperactivity disorder (ADHD) have demonstrated anatomic and functional abnormalities predominantly in frontal and striatal grey matter. Here we report the use of novel image analysis methods, which do not require prior selection of regions of interest, to characterize distributed morphological deficits of both grey and white matter associated with ADHD. Methods.

S. OVERMEYER; E. T. BULLMORE; J. SUCKLING; A. SIMMONS; S. C. R. WILLIAMS; P. J. SANTOSH; E. TAYLOR

2001-01-01

193

White matter connectivity and aerobic fitness in male adolescents.  

PubMed

Exercise has been shown to have positive effects on the brain and behavior throughout various stages of the lifespan. However, little is known about the impact of exercise on neurodevelopment during the adolescent years, particularly with regard to white matter microstructure, as assessed by diffusion tensor imaging (DTI). Both tract-based spatial statistics (TBSS) and tractography-based along-tract statistics were utilized to examine the relationship between white matter microstructure and aerobic exercise in adolescent males, ages 15-18. Furthermore, we examined the data by both (1) grouping individuals based on aerobic fitness self-reports (high fit (HF) vs. low fit (LF)), and (2) using VO2 peak as a continuous variable across the entire sample. Results showed that HF youth had an overall higher number of streamline counts compared to LF peers, which was driven by group differences in corticospinal tract (CST) and anterior corpus callosum (Fminor). In addition, VO2 peak was negatively related to FA in the left CST. Together, these results suggest that aerobic fitness relates to white matter connectivity and microstructure in tracts carrying frontal and motor fibers during adolescence. Furthermore, the current study highlights the importance of considering the environmental factor of aerobic exercise when examining adolescent brain development. PMID:24333926

Herting, Megan M; Colby, John B; Sowell, Elizabeth R; Nagel, Bonnie J

2014-01-01

194

White matter microstructural organization and gait stability in older adults  

PubMed Central

Understanding age-related decline in gait stability and the role of alterations in brain structure is crucial. Here, we studied the relationship between white matter microstructural organization using Diffusion Tensor Imaging (DTI) and advanced gait stability measures in 15 healthy young adults (range 18–30 years) and 25 healthy older adults (range 62–82 years). Among the different gait stability measures, only stride time and the maximum Lyapunov exponent (which quantifies how well participants are able to attenuate small perturbations) were found to decline with age. White matter microstructural organization (FA) was lower throughout the brain in older adults. We found a strong correlation between FA in the left anterior thalamic radiation and left corticospinal tract on the one hand, and step width and safety margin (indicative of how close participants are to falling over) on the other. These findings suggest that white matter FA in tracts connecting subcortical and prefrontal areas is associated with the implementation of an effective stabilization strategy during gait.

Bruijn, Sjoerd M.; Van Impe, Annouchka; Duysens, Jacques; Swinnen, Stephan P.

2014-01-01

195

Multiple White Matter Volume Reductions in Patients with Panic Disorder: Relationships between Orbitofrontal Gyrus Volume and Symptom Severity and Social Dysfunction  

PubMed Central

Numerous brain regions are believed to be involved in the neuropathology of panic disorder (PD) including fronto-limbic regions, thalamus, brain stem, and cerebellum. However, while several previous studies have demonstrated volumetric gray matter reductions in these brain regions, there have been no studies evaluating volumetric white matter changes in the fiber bundles connecting these regions. In addition, although patients with PD typically exhibit social, interpersonal and occupational dysfunction, the neuropathologies underlying these dysfunctions remain unclear. A voxel-based morphometry study was conducted to evaluate differences in regional white matter volume between 40 patients with PD and 40 healthy control subjects (HC). Correlation analyses were performed between the regional white matter volumes and patients' scores on the Panic Disorder Severity Scale (PDSS) and the Global Assessment of Functioning (GAF). Patients with PD demonstrated significant volumetric reductions in widespread white matter regions including fronto-limbic, thalamo-cortical and cerebellar pathways (p<0.05, FDR corrected). Furthermore, there was a significant negative relationship between right orbitofrontal gyrus (OFG) white matter volume and the severity of patients' clinical symptoms, as assessed with the PDSS. A significant positive relationship was also observed between patients' right OFG volumes and their scores on the GAF. Our results suggest that volumetric reductions in widespread white matter regions may play an important role in the pathology of PD. In particular, our results suggest that structural white matter abnormalities in the right OFG may contribute to the social, personal and occupational dysfunction typically experienced by patients with PD.

Konishi, Jun; Asami, Takeshi; Hayano, Fumi; Yoshimi, Asuka; Hayasaka, Shunsuke; Fukushima, Hiroshi; Whitford, Thomas J.; Inoue, Tomio; Hirayasu, Yoshio

2014-01-01

196

MRI Markers for Mild Cognitive Impairment: Comparisons between White Matter Integrity and Gray Matter Volume Measurements  

PubMed Central

The aim of the study was to evaluate the value of assessing white matter integrity using diffusion tensor imaging (DTI) for classification of mild cognitive impairment (MCI) and prediction of cognitive impairments in comparison to brain atrophy measurements using structural MRI. Fifty-one patients with MCI and 66 cognitive normal controls (CN) underwent DTI and T1-weighted structural MRI. DTI measures included fractional anisotropy (FA) and radial diffusivity (DR) from 20 predetermined regions-of-interest (ROIs) in the commissural, limbic and association tracts, which are thought to be involved in Alzheimer's disease; measures of regional gray matter (GM) volume included 21 ROIs in medial temporal lobe, parietal cortex, and subcortical regions. Significant group differences between MCI and CN were detected by each MRI modality: In particular, reduced FA was found in splenium, left isthmus cingulum and fornix; increased DR was found in splenium, left isthmus cingulum and bilateral uncinate fasciculi; reduced GM volume was found in bilateral hippocampi, left entorhinal cortex, right amygdala and bilateral thalamus; and thinner cortex was found in the left entorhinal cortex. Group classifications based on FA or DR was significant and better than classifications based on GM volume. Using either DR or FA together with GM volume improved classification accuracy. Furthermore, all three measures, FA, DR and GM volume were similarly accurate in predicting cognitive performance in MCI patients. Taken together, the results imply that DTI measures are as accurate as measures of GM volume in detecting brain alterations that are associated with cognitive impairment. Furthermore, a combination of DTI and structural MRI measurements improves classification accuracy.

Zhang, Yu; Schuff, Norbert; Camacho, Monica; Chao, Linda L.; Fletcher, Thomas P.; Yaffe, Kristine; Woolley, Susan C.; Madison, Catherine; Rosen, Howard J.; Miller, Bruce L.; Weiner, Michael W.

2013-01-01

197

Individual Differences in Expert Motor Coordination Associated with White Matter Microstructure in the Cerebellum  

PubMed Central

Recent investigations into the neural basis of elite sporting performance have focused on whether cortical activity might characterize individual differences in ability. However, very little is understood about how changes in brain structure might contribute to individual differences in expert motor control. We compared the behavior and brain structure of healthy controls with a group of karate black belts, an expert group who are able to perform rapid, complex movements that require years of training. Using 3D motion tracking, we investigated whether the ability to control ballistic arm movements was associated with differences in white matter microstructure. We found that karate experts are better able than novices to coordinate the timing of inter-segmental joint velocities. Diffusion tensor imaging revealed significant differences between the groups in the microstructure of white matter in the superior cerebellar peduncles (SCPs) and primary motor cortex—brain regions that are critical to the voluntary control of movement. Motor coordination, the amount of experience, and the age at which training began were all associated with individual differences in white matter integrity in the cerebellum within the karate groups. These findings suggest a role for the white matter pathways of the SCPs in motor expertise.

Roberts, R.E.; Bain, P.G.; Day, B.L.; Husain, M.

2013-01-01

198

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

199

Common genetic variants and gene expression associated with white matter microstructure in the human brain.  

PubMed

Identifying genes that contribute to white matter microstructure should provide insights into the neurobiological processes that regulate white matter development, plasticity and pathology. We detected five significant SNPs using genome-wide association analysis on a global measure of fractional anisotropy in 776 individuals from large extended pedigrees. Genetic correlations and genome-wide association results indicated that the genetic signal was largely homogeneous across white matter regions. Using RNA transcripts derived from lymphocytes in the same individuals, we identified two genes (GNA13 and CCDC91) that are likely to be cis-regulated by top SNPs, and whose expression levels were also genetically correlated with fractional anisotropy. A transcript of HTR7 was phenotypically associated with FA, and was associated with an intronic genome-wide significant SNP. These results encourage further research in the mechanisms by which GNA13, HTR7 and CCDC91 influence brain structure, and emphasize a role for g-protein signaling in the development and maintenance of white matter microstructure in health and disease. PMID:24736177

Sprooten, Emma; Knowles, Emma E; McKay, D Reese; Göring, Harald H; Curran, Joanne E; Kent, Jack W; Carless, Melanie A; Dyer, Thomas D; Drigalenko, Eugene I; Olvera, Rene L; Fox, Peter T; Almasy, Laura; Duggirala, Ravi; Kochunov, Peter; Blangero, John; Glahn, David C

2014-08-15

200

Alterations of white matter integrity related to the season of birth in schizophrenia: a DTI study.  

PubMed

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. PMID:24086548

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

2013-01-01

201

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

202

Multivariate pattern analysis of DTI reveals differential white matter in individuals with obsessive-compulsive disorder.  

PubMed

Diffusion tensor imaging (DTI) studies have revealed group differences in white matter between patients with obsessive-compulsive disorder (OCD) and healthy controls. However, the results of these studies were based on average differences between the two groups, and therefore had limited clinical applicability. The objective of this study was to investigate whether fractional anisotropy (FA) of white matter can be used to discriminate between patients with OCD and healthy controls at the level of the individual. DTI data were acquired from 28 OCD patients and 28 demographically matched healthy controls, scanned using a 3T MRI system. Differences in FA values of white matter between OCD and healthy controls were examined using a multivariate pattern classification technique known as support vector machine (SVM). SVM applied to FA images correctly identified OCD patients with a sensitivity of 86% and a specificity of 82% resulting in a statistically significant accuracy of 84% (P ? 0.001). This discrimination was based on a distributed network including bilateral prefrontal and temporal regions, inferior fronto-occipital fasciculus, superior fronto-parietal fasciculus, splenium of corpus callosum and left middle cingulum bundle. The present study demonstrates subtle and spatially distributed white matter abnormalities in individuals with OCD, and provides preliminary support for the suggestion that that these could be used to aid the identification of individuals with OCD in clinical practice. PMID:24048702

Li, Fei; Huang, Xiaoqi; Tang, Wanjie; Yang, Yanchun; Li, Bin; Kemp, Graham J; Mechelli, Andrea; Gong, Qiyong

2014-06-01

203

Method for Combining Information from White Matter Fiber Tracking and Gray Matter Parcellation  

Microsoft Academic Search

Summary: We introduce a method for combining fiber tracking from diffusion-tensor (DT) imaging with cortical gray matter parcellation from structural high-spatial- resolution 3D spoiled gradient-recalled acquisition in the steady state images. We applied this method to a tumor case to determine the impact of the tumor on white matter architecture. We conclude that this new method for com- bining structural

Hae-Jeong Park; Marek Kubicki; Carl-Fredrik Westin; Ion-Florin Talos; Anders Brun; Steve Peiper; Ron Kikinis; Ference A. Jolesz; Robert W. McCarley; Martha E. Shenton

2004-01-01

204

Cortical and white matter alterations in patients with neuropathic pain after spinal cord injury.  

PubMed

Neuropathic pain is one of the major problems of patients with spinal cord injury (SCI), which remains refractory to treatment despite a variety of therapeutic approach. Multimodal neuroimaging could provide complementary information for brain mechanisms underlying neuropathic pain, which could be based on development of more effective treatment strategies. Ten patients suffering from chronic neuropathic pain after SCI and 10 healthy controls underwent FDG-PET, T1-anatomical MRI and diffusion tensor imaging. We found decreases of both metabolism and the gray matter volume in the left dorsolateral prefrontal cortex in patients compared to healthy controls, as well as hypometabolism in the medial prefrontal cortex and gray matter volume loss in bilateral anterior insulae and subgenual anterior cingulate cortices. These brain regions are generally known to participate in pain modulation by affective and cognitive processes. Decreases of mean diffusivity (MD) in the right internal capsule including, cerebral peduncle, pre-and post-central white matter, and prefrontal white matter as components of the corticospinal and thalamocortical tracts were demonstrated in patients. Further, lower MD value of prefrontal white matter was correlated with decreased metabolism of medial prefrontal cortex in patients. These results indicated that white matter changes imply abnormal pain modulation in patients as well as motor impairment. Our study showed the functional and structural multimodal imaging modality commonly identified the possible abnormalities in the brain regions participating pain modulation in neuropathic pain. Multifaceted imaging studies in neuropathic pain could be useful elucidating precise mechanisms of persistent pain, and providing future directions for treatment. PMID:24125807

Yoon, Eun Jin; Kim, Yu Kyeong; Shin, Hyung Ik; Lee, Youngjo; Kim, Sang Eun

2013-12-01

205

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 I.; Albert, Marilyn; Jolesz, Ferenc A.

1997-04-01

206

Effects of prenatal alcohol exposure on the development of white matter volume and change in executive function.  

PubMed

Prenatal alcohol exposure can cause a wide range of deficits in executive function that persist throughout life, but little is known about how changes in brain structure relate to cognition in affected individuals. In the current study, we predicted that the rate of white matter volumetric development would be atypical in children with fetal alcohol spectrum disorders (FASD) when compared to typically developing children, and that the rate of change in cognitive function would relate to differential white matter development between groups. Data were available for 103 subjects [49 with FASD, 54 controls, age range 6-17, mean age = 11.83] with 153 total observations. Groups were age-matched. Participants underwent structural magnetic resonance imaging (MRI) and an executive function (EF) battery. Using white matter volumes measured bilaterally for frontal and parietal regions and the corpus callosum, change was predicted by modeling the effects of age, intracranial volume, sex, and interactions with exposure status and EF measures. While both groups showed regional increases in white matter volumes and improvement in cognitive performance over time, there were significant effects of exposure status on age-related relationships between white matter increases and EF measures. Specifically, individuals with FASD consistently showed a positive relationship between improved cognitive function and increased white matter volume over time, while no such relationships were seen in controls. These novel results relating improved cognitive function with increased white matter volume in FASD suggest that better cognitive outcomes could be possible for FASD subjects through interventions that enhance white matter plasticity. PMID:24918069

Gautam, P; Nuñez, S C; Narr, K L; Kan, E C; Sowell, E R

2014-01-01

207

Response inhibition is associated with white matter microstructure in children.  

PubMed

Cognitive control of thoughts, actions and emotions is important for normal behaviour and the development of such control continues throughout childhood and adolescence. Several lines of evidence suggest that response inhibition is primarily mediated by a right-lateralized network involving inferior frontal gyrus (IFG), presupplementary motor cortex (preSMA), and subthalamic nucleus. Though the brain's fibre tracts are known to develop during childhood, little is known about how fibre tract development within this network relates to developing behavioural control. Here we examined the relationship between response inhibition, as measured with the stop-signal task, and indices of regional white matter microstructure in typically-developing children. We hypothesized that better response inhibition performance would be associated with higher fractional anisotropy (FA) in fibre tracts within right IFG and preSMA after controlling for age. Mean FA and diffusivity values were extracted from right and left IFG and preSMA. As hypothesized, faster response inhibition was significantly associated with higher FA and lower perpendicular diffusivity in both the right IFG and the right preSMA, possibly reflecting faster speed of neural conduction within more densely packed or better myelinated fibre tracts. Moreover, both of these effects remained significant after controlling for age and whole brain estimates of these DTI parameters. Interestingly, right IFG and preSMA FA contributed additively to the prediction of performance variability. Observed associations may be related to variation in phase of maturation, to activity-dependent alterations in the network subserving response inhibition, or to stable individual differences in underlying neural system connectivity. PMID:19909763

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

2010-03-01

208

Diffusion Tensor Imaging Segmentation of White Matter Structures Using a Reproducible Objective Quantification Scheme (ROQS)  

PubMed Central

Reproducible Objective Quantification Scheme (ROQS) is a novel method for regional white matter measurements of diffusion tensor imaging (DTI) parameters that overcomes the limitations of previous approaches for analyzing large cohorts of subjects reliably. ROQS is a semi-automated technique that exploits the fiber orientation information from the diffusion tensor in conjunction with a binary masking and chain-linking algorithm to segment anatomically distinct white matter tracts for subsequent quantitative analysis of DTI parameters such as fractional anisotropy and apparent diffusion coefficient. When applied to 3 Tesla whole-brain DTI of normal adult volunteers, ROQS is shown to segment the corpus callosum much faster than manual region of interest (ROI) delineation, and with better reproducibility and accuracy.

Niogi, Sumit N.; Mukherjee, Pratik; McCandliss, Bruce D.

2009-01-01

209

Assessment of white matter abnormalities in paranoid schizophrenia and bipolar mania patients.  

PubMed

White matter abnormalities have been repeatedly reported in both schizophrenia and bipolar disorder (BD) in diffusion tensor imaging (DTI) studies, but the empirical evidence about the diagnostic specificity of white matter abnormalities in these disorders is still limited. This study sought to investigate the alterations in fractional anisotropy (FA) in white matter throughout the entire brain of patients from Chengdu, China with paranoid schizophrenia and bipolar mania. For this purpose, DTI was used to assess white matter integrity in patients with paranoid schizophrenia (n=25) and psychotic bipolar mania (n=18) who had been treated with standard pharmacotherapy for fewer than 5 days at the time of study, as well as in normal controls (n=30). The differences in FA were measured by use of voxel-based analysis. The results show that reduced FA was found in the left posterior corona radiata (PCR) in patients with psychotic bipolar mania and paranoid schizophrenia compared to the controls. Patients with psychotic bipolar mania also showed a significant reduction in FA in right posterior corona radiata and in right anterior thalamic radiation (ATR). A direct comparison between the two patient groups found no significant differences in any regions, and none of the findings were associated with illness duration. Correlation analysis indicated that FA values showed a significant negative correlation with positive symptom scores on the Positive and Negative Syndrome Scale in the left frontal-parietal lobe in the paranoid schizophrenia. It was concluded that common abnormalities in the left PCR might imply an overlap in white matter pathology in the two disorders and might be related to shared risk factors for the two disorders. PMID:22079662

Cui, Liqian; Chen, Zhuangfei; Deng, Wei; Huang, Xiaoqi; Li, Mingli; Ma, Xiaohong; Huang, Chaohua; Jiang, Lijun; Wang, Yingcheng; Wang, Qiang; Collier, David A; Gong, Qiyong; Li, Tao

2011-12-30

210

Cerebral small vessel disease affects white matter microstructure in mild cognitive impairment.  

PubMed

Microstructural white matter deterioration is a frequent finding in mild cognitive impairment (MCI), potentially underlying default mode network (DMN) dysfunctioning. Thus far, microstructural damage in MCI has been attributed to Alzheimer's disease pathophysiology. A cerebrovascular role, in particular the role of cerebral small vessel disease (CSVD), received less interest. Here, we used diffusion tensor imaging (DTI) to examine the role of CSVD in microstructural deterioration within the normal appearing white matter (NAWM) in MCI. MCI patients were subdivided into those with (n = 20) and without (n = 31) macrostructural CSVD evidence on MRI. Using TBSS we performed microstructural integrity comparisons within the whole brain NAWM. Secondly, we segmented white matter tracts interconnecting DMN brain regions by means of automated tractography segmentation. We used NAWM DTI measures from these tracts as dependent variables in a stepwise-linear regression analysis, with structural and demographical predictors. Our results indicated microstructural deterioration within the anterior corpus callosum, internal and external capsule and periventricular white matter in MCI patients with CSVD, while in MCI patients without CSVD, deterioration was restricted to the right perforant path, a tract along the hippocampus. Within the full cohort of MCI patients, microstructure within the NAWM of the DMN fiber tracts was affected by the presence of CSVD. Within the cingulum along the hippocampal cortex we found a relationship between microstructural integrity and ipsilateral hippocampal volume and the extent of white matter hyperintensity. In conclusion, we found evidence of CSVD-related microstructural damage in fiber tracts subserving the DMN in MCI. Hum Brain Mapp 35:2836-2851, 2014. © 2013 Wiley Periodicals, Inc. PMID:24115179

Papma, Janne M; de Groot, Marius; de Koning, Inge; Mattace-Raso, Francesco U; van der Lugt, Aad; Vernooij, Meike W; Niessen, Wiro J; van Swieten, John C; Koudstaal, Peter J; Prins, Niels D; Smits, Marion

2014-06-01

211

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

212

White matter abnormalities in bipolar disorder: insights from diffusion tensor imaging studies  

Microsoft Academic Search

Diffusion tensor imaging (DTI) is a neuroimaging technique with the potential to elucidate white matter abnormalities. Recently,\\u000a it has been applied to help in better understanding of the pathophysiology of bipolar disorder (BD). This review sought to\\u000a synthesise existing literature on DTI studies in BD, summarise current findings and highlight brain regions that have consistently\\u000a been implicated in BD, as

Serene Heng; Allen W. Song; Kang Sim

2010-01-01

213

Proton magnetic resonance spectroscopy of periventricular white matter and hippocampus in obstructive sleep apnea patients  

PubMed Central

Summary Background The purpose of this study was to diagnose the hypoxic impairment by Magnetic resonance spectroscopy (MRS), an advanced MR imaging technique, which could not be visualised by routine imaging methods in patients with obstructive sleep apnea (OSA). Material/Methods 20 OSA patients and 5 controls were included in this prospective research. MRS was performed on these 25 subjects to examine cerebral hypoxemia in specific regions (periventricular white matter and both hippocampi). Polysomnography was assumed as the gold standard. Statistical analysis was assessed by Mann-Whitney U test and Receiver operating characteristics (ROC) curve for NAA/Cho, NAA/Cr and Cho/Cr ratios. Results In the periventricular white matter, NAA/Cho ratio in OSA patients was significantly lower than in the control group (p<0.05). There were no statistical differences between the OSA and the control group for NAA/Cho, NAA/Cr and Cho/Cr ratios for both hippocampal regions. Additionally, Cho/Cr ratio in the periventricular white matter region of OSA group was higher than in the control group (p<0.05). Conclusions Hypoxic impairment induced by repeated episodes of apnea leads to significant neuronal damage in OSA patients. MRS provides valuable information in the assessment of hypoxic ischemic impairment by revealing important metabolite ratios for the specific areas of the brain.

K?z?lgoz, Volkan; Ayd?n, Hasan; Tatar, Idil Gunes; Hekimoglu, Baki; Ard?c, Sad?k; F?rat, Hikmet; Donmez, Cem

2013-01-01

214

Alterations in white matter pathways in Angelman syndrome  

PubMed Central

Aim Angelman syndrome is a neurogenetic disorder characterized by severe intellectual disability, absent speech, seizures, and outbursts of laughter. The aim of this study was to utilize diffusion tensor imaging (DTI) to examine alterations in white matter pathways in Angelman syndrome, with an emphasis on correlations with clinical severity. Methods DTI was used to examine the arcuate fasciculus (AF), uncinate fasciculus (UF), inferior longitudinal fasciculus (ILF), inferior fronto-occipital fasciculus (IFOF), and the corpus callosum (CC). We enrolled 14 children aged 8 to 17 years (mean age 10y 8mo; SD 2y 7mo) with Angelman syndrome (seven male; seven female) and 13 typically developing children, aged 8 to 17 years, for comparison (five male; eight female; mean age 12y; SD 2y 9mo). Individuals with Angelman syndrome were assessed using standardized measures of development, language, and behaviour. Results The children with Angelman syndrome exhibited lower fractional anisotropy and increased radial diffusivity values than the comparison group for the AF, UF, ILF, and CC (p<0.006 corrected for multiple comparisons). They also had lower fractional anisotropy values for the IFOF and higher radial diffusivity values for the left IFOF (p<0.006). Additionally, children with Angelman syndrome had significantly higher apparent diffusion coefficient values in the AF, CC, ILF, and the left IFOF (p<0.006). Significant correlations were noted between DTI parameters and some of the clinical assessment outcomes (e.g. language, socialization, cognition) for three of the temporal pathways (AF, UF, ILF; p<0.05). Interpretation Changes in DTI parameters in individuals with Angelman syndrome suggest decreased/delayed myelination, decreased axonal density or diameter, or aberrant axonal organization. Our findings suggest a generalized white matter alteration throughout the brain in those with Angelman syndrome; however, only the alterations in temporal white matter pathways were associated with language and cognitive and social functioning.

PETERS, SARIKA U; KAUFMANN, WALTER E; BACINO, CARLOS A; ANDERSON, ADAM W; ADAPA, PAVANI; CHU, ZILI; YALLAMPALLI, RAGINI; TRAIPE, ELFRIDES; HUNTER, JILL V; WILDE, ELISABETH A

2010-01-01

215

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

216

Influence of white matter inhomogeneous anisotropy on EEG forward computing.  

PubMed

In this paper, we model the human head using the Volume and Wang's constraint methods, and study the inhomogeneous anisotropic conductivity for white matter (WM) using finite element method (FEM). To represent the WM accurately, the conductivity ratio approximation (CRA) and statistical conductivity approximation (SCA) techniques are applied to assign inhomogeneous anisotropic conductivity. This model is evaluated and compared with a homogeneous isotropic model and a homogeneous anisotropic model. The results show that the effects of inhomogeneous anisotropic conductivity ofWM on the scalp EEG are significant. PMID:18697703

Bashar, R; Li, Y; Wen, P

2008-06-01

217

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

218

Albuminuria, Cognitive Functioning and White Matter Hyperintensities in Homebound Elders  

PubMed Central

Background Albuminuria, a kidney marker of microvascular disease, may herald microvascular disease elsewhere, including in the brain. Study Design Cross sectional. Setting and Participants Boston, MA (USA) elders receiving home health services to maintain independent living who consented to brain magnetic resonance imaging. Predictor Urine albumin to creatinine ratio (ACR). Outcome Performance on a cognitive battery assessing executive function and memory using principal components analysis and white matter hyperintensity volume on brain imaging, evaluated in logistic and linear regression models. Results Of 335 participants, mean age was 73.4 ± 8.1 years; 123 participants had microalbuminuria or macroalbuminuria. Each doubling of ACR was associated with worse executive function [?=-0.05 (p=0.005) in univariate and ?=-0.07 (p=0.004) in multivariable analyses controlling for age, sex, race, education, diabetes, cardiovascular disease, hypertension, medications, and estimated glomerular filtration rate] but not with worse memory or working memory. Individuals with microalbuminuria or macroalbuminuria were more likely to be in the lower versus the highest tertile of executive functioning [Odds ratio =1.18 (1.06 to 1.32) and 1.19 (1.05 to 1.35) per doubling of ACR in univariate and multivariable analyses, respectively]. Albuminuria was associated with qualitative white matter hyperintensity grade [Odds ratio =1.13 (1.02 to 1.25) and 1.15 (1.02 to 1.29) per doubling of ACR] in univariate and multivariable analyses, and with quantitative white matter hyperintensity volume [?=0.11 (p=0.007) and ?=0.10 (p=0.01)] in univariate and multivariable analyses of log-transformed data, respectively. Results were similar when excluding individuals with macroalbuminuria. Limitations Single measurement of ACR, indirect creatinine calibration and reliance on participant recall for elements of medical history Conclusions Albuminuria is associated with worse cognitive performance, particularly in executive functioning, as well as increased white matter hyperintensity volume. Albuminuria likely identifies greater brain microvascular disease burden.

Weiner, Daniel E.; Bartolomei, Keith; Scott, Tammy; Price, Lori Lyn; Griffith, John L.; Rosenberg, Irwin; Levey, Andrew S.; Folstein, Marshal F.; Sarnak, Mark J.

2009-01-01

219

White matter/gray matter contrast changes in chronic and diffuse traumatic brain injury.  

PubMed

Signal-intensity contrast of T1-weighted magnetic resonance imaging scans has been associated with tissue integrity and reported as a sign of neurodegenerative changes in diseases such as Alzheimer's disease. After severe traumatic brain injury (TBI), progressive structural changes occur in white (WM) and gray matter (GM). In the current study, we assessed the signal-intensity contrast of GM and WM in patients with diffuse TBI in the chronic stage to (1) characterize the regional pattern of WM/GM changes in intensity contrast associated with traumatic axonal injury, (2) evaluate possible associations between this measure and diffusion tensor image (DTI)/fractional anisotropy (FA) for detecting WM damage, and (3) investigate the correlates of both measures with cognitive outcomes. Structural T1 scans were processed with FreeSurfer software to identify the boundary and calculate the WM/GM contrast maps. DTIs were processed with the FMRIB software library to obtain FA maps. The WM/GM contrast in TBI patients showed a pattern of reduction in almost all of the brain, except the visual and motor primary regions. Global FA values obtained from DTI correlated with the intensity contrast of all associative cerebral regions. WM/GM contrast correlated with memory functions, whereas FA global values correlated with tests measuring memory and mental processing speed. In conclusion, tissue-contrast intensity is a very sensitive measure for detecting structural brain damage in chronic, severe and diffuse TBI, but is less sensitive than FA for reflecting neuropsychological sequelae, such as impaired mental processing speed. PMID:23822854

Palacios, Eva M; Sala-Llonch, Roser; Junque, Carme; Roig, Teresa; Tormos, Jose M; Bargallo, Nuria; Vendrell, Pere

2013-12-01

220

Connecting white matter injury and thalamic atrophy in clinically isolated syndromes  

Microsoft Academic Search

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

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

2009-01-01

221

Early-Stage Psychotherapy Produces Elevated Frontal White Matter Integrity in Adult Major Depressive Disorder  

PubMed Central

Background Psychotherapy has demonstrated comparable efficacy to antidepressant medication in the treatment of major depressive disorder. Metabolic alterations in the MDD state and in response to treatment have been detected by functional imaging methods, but the underlying white matter microstructural changes remain unknown. The goal of this study is to apply diffusion tensor imaging techniques to investigate psychotherapy-specific responses in the white matter. Methods Twenty-one of forty-five outpatients diagnosed with major depression underwent diffusion tensor imaging before and after a four-week course of guided imagery psychotherapy. We compared fractional anisotropy in depressed patients (n?=?21) with healthy controls (n?=?22), and before-after treatment, using whole brain voxel-wise analysis. Results Post-treatment, depressed subjects showed a significant reduction in the 17-item Hamilton Depression Rating Scale. As compared to healthy controls, depressed subjects demonstrated significantly increased fractional anisotropy in the right thalamus. Psychopathological changes did not recover post-treatment, but a novel region of increased fractional anisotropy was discovered in the frontal lobe. Conclusions At an early stage of psychotherapy, higher fractional anisotropy was detected in the frontal emotional regulation-associated region. This finding reveals that psychotherapy may induce white matter changes in the frontal lobe. This remodeling of frontal connections within mood regulation networks positively contributes to the “top-down” mechanism of psychotherapy.

Lv, Fajin; Zhang, Yong; Zhou, Linke; Yang, Deyu; Xie, Peng

2013-01-01

222

Grammar learning in older adults is linked to white matter microstructure and functional connectivity.  

PubMed

Age-related decline in cognitive function has been linked to alterations of white matter and functional brain connectivity. With regard to language, aging has been shown to be associated with impaired syntax processing, but the underlying structural and functional correlates are poorly understood. In the present study, we used an artificial grammar learning (AGL) task to determine the ability to extract grammatical rules from new material in healthy older adults. White matter microstructure and resting-state functional connectivity (FC) of task-relevant brain regions were assessed using multimodal magnetic resonance imaging (MRI). AGL performance correlated positively with fractional anisotropy (FA) underlying left and right Brodmann areas (BA) 44/45 and in tracts originating from left BA 44/45. An inverse relationship was found between task performance and FC of left and right BA 44/45, linking lower performance to stronger inter-hemispheric functional coupling. Our results suggest that white matter microstructure underlying specific prefrontal regions and their functional coupling affect acquisition of syntactic knowledge in the aging brain, offering further insight into mechanisms of functional decline in older adults. PMID:22659480

Antonenko, Daria; Meinzer, Marcus; Lindenberg, Robert; Witte, A Veronica; Flöel, Agnes

2012-09-01

223

Microstructural abnormalities in white matter and their effect on depressive symptoms after stroke.  

PubMed

The aim of the study was to investigate the existence of microstructural abnormalities in the white matter of the brain in stroke patients, as well as the relationship between these microstructural abnormalities and changes in depressive symptoms over 6 months. Participants were 29 acute ischemic stroke patients and 37 healthy control subjects. Depressive symptoms were assessed in all subjects using the Hamilton Rating Scale for Depression and the Zung Self-rating Depression Scale. Whole brain voxel-based analysis was used to compare diffusion tensor imaging measures of Fractional Anisotropy (FA) between the groups. Six-month follow-up examinations were conducted. Patients showed significantly lower white matter FA values in the left and right anterior limbs of the internal capsule, and 6 months after the stroke they showed significantly increased FA values in these regions. We found a significant negative correlation between the increased ratio of the FA values and the change in depression scale scores at 6-month follow-up. Regional white matter damage may reflect abnormalities in neuroanatomical pathways related to the pathophysiology of depression. PMID:24816338

Yasuno, Fumihiko; Taguchi, Akihiko; Yamamoto, Akihide; Kajimoto, Katsufumi; Kazui, Hiroaki; Sekiyama, Atsuo; Matsuoka, Kiwamu; Kitamura, Soichiro; Kiuchi, Kuniaki; Kosaka, Jun; Kishimoto, Toshifumi; Iida, Hidehiro; Nagatsuka, Kazuyuki

2014-07-30

224

White matter anisotropy related to electrophysiology of first episode schizophrenia during NoGo inhibition.  

PubMed

Patients with schizophrenia have reduced execution functions and white matter alterations indicating cerebral disconnectivity. Here we investigated the relationship between white matter integrity and event related potentials (ERP) during a continuous performance test (CPT). Anisotropy values were correlated with the brain electrical P300 microstate duration and P300 latency associated to the NoGo- and the Go-stimuli of the CPT in 11 patients with first episode schizophrenia and 11 matched healthy controls. Both groups showed significant positive correlations of the NoGo-microstate duration with the white matter signal in the superior frontal region, the optic radiation, the posterior cingulate, and the inferolateral fascicle. In addition, patients with first episode schizophrenia had significant correlations with the right radiation and the left genu of the corpus callosum, bilateral geniculate, and the left middle and the superior temporal regions. We interpreted these findings as a sign of functional correlates of extended circuits for the active inhibition of a motor response in the visual CPT as compared to controls. PMID:18356066

Begré, Stefan; Kleinlogel, Horst; Kiefer, Claus; Strik, Werner; Dierks, Thomas; Federspiel, Andrea

2008-05-01

225

Segregation of the Brain into Gray and White Matter: A Design Minimizing Conduction Delays  

PubMed Central

A ubiquitous feature of the vertebrate anatomy is the segregation of the brain into white and gray matter. Assuming that evolution maximized brain functionality, what is the reason for such segregation? To answer this question, we posit that brain functionality requires high interconnectivity and short conduction delays. Based on this assumption we searched for the optimal brain architecture by comparing different candidate designs. We found that the optimal design depends on the number of neurons, interneuronal connectivity, and axon diameter. In particular, the requirement to connect neurons with many fast axons drives the segregation of the brain into white and gray matter. These results provide a possible explanation for the structure of various regions of the vertebrate brain, such as the mammalian neocortex and neostriatum, the avian telencephalon, and the spinal cord.

Wen, Quan; Chklovskii, Dmitri B

2005-01-01

226

Neuropsychiatric correlates of white matter hyperintensities in Alzheimer's disease  

PubMed Central

Objective To investigate the association of behavioral and psychological symptoms of dementia (BPSD) in Alzheimer’s disease (AD) and MRI measures of brain atrophy and white matter hyperintensities (WMH). Methods Thirty-seven patients with probable AD received the Neuropsychiatric Inventory (NPI), the Mini Mental Status Exam (MMSE), and an MRI scan as part of their initial evaluation at the Outpatient Memory Diagnostic Clinic at McLean Hospital. MRI-based volumetric measurements of whole brain atrophy, hippocampal volumes and WMH were obtained. Analysis of covariance models, using age as a covariate and the presence of specific BPSD as independent variables, were used to test for differences in whole brain volumes, hippocampal volumes and WMH volumes. Results Increased WMH were associated with symptoms of anxiety, aberrant motor behavior, and nighttime disturbance, while symptoms of disinhibition were linked to lower WMH volume. No associations were found for of whole brain or hippocampal volumes and BPSD. Conclusions These findings suggest that white matter changes are associated with the presence of BPSD in AD.

Berlow, Yosef A.; Wells, William M.; Ellison, James; Sung, Young Hoon; Renshaw, Perry F.; Harper, David G.

2013-01-01

227

White Matter Integrity is Reduced in Bulimia Nervosa  

PubMed Central

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

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

2013-01-01

228

Method for combining information from white matter fiber tracking and gray matter parcellation.  

PubMed

We introduce a method for combining fiber tracking from diffusion-tensor (DT) imaging with cortical gray matter parcellation from structural high-spatial-resolution 3D spoiled gradient-recalled acquisition in the steady state images. We applied this method to a tumor case to determine the impact of the tumor on white matter architecture. We conclude that this new method for combining structural and DT imaging data is useful for understanding cortical connectivity and the localization of fiber tracts and their relationship with cortical anatomy and brain abnormalities. PMID:15466325

Park, Hae-Jeong; Kubicki, Marek; Westin, Carl-Fredrik; Talos, Ion-Florin; Brun, Anders; Peiper, Steve; Kikinis, Ron; Jolesz, Ference A; McCarley, Robert W; Shenton, Martha E

2004-09-01

229

Oligodendroglial alterations and the role of microglia in white matter injury: relevance to schizophrenia.  

PubMed

Schizophrenia is a chronic and debilitating mental illness characterized by a broad range of abnormal behaviors, including delusions and hallucinations, impaired cognitive function, as well as mood disturbances and social withdrawal. Due to the heterogeneous nature of the disease, the causes of schizophrenia are very complex; its etiology is believed to involve multiple brain regions and the connections between them, and includes alterations in both gray and white matter regions. The onset of symptoms varies with age and severity, and there is some debate over a degenerative or developmental etiology. Longitudinal magnetic resonance imaging studies have detected progressive gray matter loss in the first years of disease, suggesting neurodegeneration; but there is also increasing recognition of a temporal association between clinical complications at birth and disease onset that supports a neurodevelopmental origin. Presently, neuronal abnormalities in schizophrenia are better understood than alterations in myelin-producing cells of the brain, the oligodendrocytes, which are the predominant constituents of white matter structures. Proper white matter development and its structural integrity critically impacts brain connectivity, which affects sensorimotor coordination and cognitive ability. Evidence of defective white matter growth and compromised white matter integrity has been found in individuals at high risk of psychosis, and decreased numbers of mature oligodendrocytes are detected in schizophrenia patients. Inflammatory markers, including proinflammatory cytokines and chemokines, are also associated with psychosis. A relationship between risk of psychosis, white matter defects and prenatal inflammation is being established. Animal models of perinatal brain injury are successful in producing white matter damage in the brain, typified by hypomyelination and/or dysmyelination, impaired motor coordination and prepulse inhibition of the acoustic startle reflex, recapitulating structural and functional characteristics observed in schizophrenia. In addition, elevated expression of inflammation-related genes in brain tissue and increased production of cytokines by blood cells from patients with schizophrenia indicate immunological dysfunction and abnormal inflammatory responses, which are also important underlying features in experimental models. Microglia, resident immune defenders of the central nervous system, play important roles in the development and protection of neural cells, but can contribute to injury under pathological conditions. This article discusses oligodendroglial changes in schizophrenia and focuses on microglial activity in the context of the disease, in neonatal brain injury and in various experimental models of white matter damage. These include disorders associated with premature birth, and animal models of perinatal bacterial and viral infection, oxygen deprivation (hypoxia) and excess (hyperoxia), and elevated systemic proinflammatory cytokine levels. We briefly review the effects of treatment with antipsychotic and anti-inflammatory agents in models of perinatal brain injury, and comment on the therapeutic potential of these strategies. By understanding the neurobiological basis of oligodendroglial abnormalities in schizophrenia, it is hoped that patients will benefit from the availability of targeted and more efficacious treatment options. PMID:23446060

Chew, Li-Jin; Fusar-Poli, Paolo; Schmitz, Thomas

2013-01-01

230

Association of Apolipoprotein E 2 With White Matter Disease but Not With Microbleeds  

Microsoft Academic Search

Background and Purpose—Apolipoprotein E (apoE) alleles (2 and 4) are associated with cerebral amyloid angiopathy, in which white matter disease and microbleeds are prominent features. The role of apoE in patients with microbleeds or white matter disease but no evidence of cerebral amyloid angiopathy has not been elucidated. We studied apoE alleles in relation to white matter disease and microbleeds

Robin Lemmens; Astrid Gorner; Maarten Schrooten; Vincent Thijs

2010-01-01

231

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

232

Differential vulnerability of gray matter and white matter to intrauterine growth restriction in preterm infants at 12 months corrected age.  

PubMed

Intrauterine growth restriction (IUGR) is associated with a high risk of abnormal neurodevelopment. Underlying neuroanatomical substrates are partially documented. We hypothesized that at 12 months preterm infants would evidence specific white-matter microstructure alterations and gray-matter differences induced by severe IUGR. Twenty preterm infants with IUGR (26-34 weeks of gestation) were compared with 20 term-born infants and 20 appropriate for gestational age preterm infants of similar gestational age. Preterm groups showed no evidence of brain abnormalities. At 12 months, infants were scanned sleeping naturally. Gray-matter volumes were studied with voxel-based morphometry. White-matter microstructure was examined using tract-based spatial statistics. The relationship between diffusivity indices in white matter, gray matter volumes, and perinatal data was also investigated. Gray-matter decrements attributable to IUGR comprised amygdala, basal ganglia, thalamus and insula bilaterally, left occipital and parietal lobes, and right perirolandic area. Gray-matter volumes positively correlated with birth weight exclusively. Preterm infants had reduced FA in the corpus callosum, and increased FA in the anterior corona radiata. Additionally, IUGR infants had increased FA in the forceps minor, internal and external capsules, uncinate and fronto-occipital white matter tracts. Increased axial diffusivity was observed in several white matter tracts. Fractional anisotropy positively correlated with birth weight and gestational age at birth. These data suggest that IUGR differentially affects gray and white matter development preferentially affecting gray matter. At 12 months IUGR is associated with a specific set of structural gray-matter decrements. White matter follows an unusual developmental pattern, and is apparently affected by IUGR and prematurity combined. PMID:24361462

Padilla, Nelly; Junqué, Carme; Figueras, Francesc; Sanz-Cortes, Magdalena; Bargalló, Núria; Arranz, Angela; Donaire, Antonio; Figueras, Josep; Gratacos, Eduard

2014-01-30

233

An investigation of the white matter microstructure in motion detection using diffusion MRI.  

PubMed

One of the most widely investigated functions of the brain is vision. Whereas special attention is often paid to motion detection and its modulation by attention, comparatively still little is known about the structural background of this function. We therefore, examined the white matter microstructural background of coherent motion detection. A random-dot kinematogram paradigm was used to measure the sensitivity of healthy individuals? to movement coherence. The potential correlation was investigated between the motion detection threshold and the white matter microstructure as measured by high angular resolution diffusion MRI. The Track Based Spatial Statistics method was used to address this correlation and probabilistic tractography to reveal the connection between identified regions. A significant positive correlation was found between the behavioural data and the local fractional anisotropy in the posterior part of the right superior frontal gyrus, the right juxta-cortical superior parietal lobule, the left parietal white matter, the left superior temporal gyrus and the left optic radiation. Probabilistic tractography identified pathways that are highly similar to the segregated attention networks, which have a crucial role in the paradigm. This study draws attention to the structural determinant of a behavioural function. PMID:24833063

Csete, Gerg?; Szabó, Nikoletta; Rokszin, Alice; Tóth, Eszter; Braunitzer, Gábor; Benedek, György; Vécsei, László; Kincses, Zsigmond Tamás

2014-06-27

234

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

PubMed Central

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

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

2013-01-01

235

White Matter Abnormalities in Skin Picking Disorder: A Diffusion Tensor Imaging Study  

PubMed Central

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.

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

2013-01-01

236

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

2013-04-01

237

Cerebral white matter injury and damage to myelin sheath following whole-brain ischemia.  

PubMed

Myelin sheath, either in white matter or in other regions of brain, is vulnerable to ischemia. The specific events involved in the progression of ischemia in white matter have not yet been elucidated. The aim of this study was to determine histopathological alterations in cerebral white matter and levels of myelin basic protein (MBP) in ischemia-injured brain tissue during the acute and subacute phases of central nervous injury following whole-brain ischemia. The whole cerebral ischemia model (four-vessel occlusion (4-VO)) was established in adult Sprague-Dawley rats and MBP gene expression and protein levels in the brain tissue were measured using reverse transcription-polymerase chain reaction and enzyme-linked immunosorbent assay (ELISA) at 2 days, 4 days, 7 days, 14 days, and 28 days following ischemia. Demyelination was determined by Luxol fast blue myelin staining, routine histopathological staining, and electron microscopy in injured brain tissue. Results showed that edema, vascular dilation, focal necrosis, demyelination, adjacent reactive gliosis and inflammation occurred 7 days after ischemia in HE staining and recovered to control levels at 28 days. The absence of Luxol fast blue staining and vacuolation was clearly visible at 7 days, 14 days, and 28 days. Semiquantitative analysis showed that the transparency of myelin had decreased significantly by 7 days, 14 days, and 28 days. Demyelination and ultrastructual changes were detected 7 days after ischemia. The relative levels of MBP mRNA decreased 2 days after ischemia and this trend continued throughout the remaining four points in time. The MBP levels measured using ELISA also decreased significantly at 2 days and 4 days, but they recovered by 7 days and returned to control levels by 14 days. These results suggest that the impact of ischemia on cerebral white matter is time-sensitive and that different effects may follow different courses over time. PMID:23246926

Chen, Yingzhu; Yi, Qiong; Liu, Gang; Shen, Xue; Xuan, Lihui; Tian, Ye

2013-02-01

238

The corpus callosum: white matter or terra incognita  

PubMed Central

The corpus callosum is the largest white matter structure in the brain, consisting of 200–250 million contralateral axonal projections and the major commissural pathway connecting the hemispheres of the human brain. The pathology of the corpus callosum includes a wide variety of entities that arise from different causes such as congenital, inflammatory, tumoural, degenerative, infectious, metabolic, traumatic, vascular and toxic agents. The corpus callosum, or a specific part of it, can be affected selectively. Numerous pathologies of the corpus callosum are encountered during CT and MRI. The aim of this study is to facilitate a better understanding and thus treatment of the pathological entities of the corpus callosum by categorising them according to their causes and their manifestations in MR and CT imaging. Familiarity with its anatomy and pathology is important to the radiologist in order to recognise its disease at an early stage and help the clinician establish the optimal therapeutic approach.

Fitsiori, A; Nguyen, D; Karentzos, A; Delavelle, J; Vargas, M I

2011-01-01

239

White matter tractographies registration using Gaussian mixture modeling  

NASA Astrophysics Data System (ADS)

This paper proposes a novel and robust approach to the registration (matching) of intra-subject white matter (WM) fiber sets extracted from DT-MRI scans by Tractography. For each fiber, a feature space representation is obtained by appending the sequence of its 3D coordinates. Clustering by non-parametric adaptive mean shift provides a representative fiber for each cluster hereafter termed the fiber-mode (FM). For each FM, the parameters of a multivariate Gaussian are computed from its fiber population, leading to a mixture of Gaussians (MoG) for the whole fiber set. The number of Gaussians used for a fiber set equals the number of FM representing the set. The alignment of two fiber sets is then treated as the alignment between two MoGs, and is solved by maximizing the correlation ratio between them. Initial results are presented for real intrasubject fiber sets and synthetic transformations.

Zvitia, Orly; Mayer, Arnaldo; Greenspan, Hayit

2008-04-01

240

Hemodynamic and Metabolic Correlates of Perinatal White Matter Injury Severity  

PubMed Central

Background and Purpose Although the spectrum of perinatal white matter injury (WMI) in preterm infants is shifting from cystic encephalomalacia to milder forms of WMI, the factors that contribute to this changing spectrum are unclear. We hypothesized that the variability in WMI quantified by immunohistochemical markers of inflammation could be correlated with the severity of impaired blood oxygen, glucose and lactate. Methods We employed a preterm fetal sheep model of in utero moderate hypoxemia and global severe but not complete cerebral ischemia that reproduces the spectrum of human WMI. Since there is small but measurable residual brain blood flow during occlusion, we sought to determine if the metabolic state of the residual arterial blood was associated with severity of WMI. Near the conclusion of hypoxia-ischemia, we recorded cephalic arterial blood pressure, blood oxygen, glucose and lactate levels. To define the spectrum of WMI, an ordinal WMI rating scale was compared against an unbiased quantitative image analysis protocol that provided continuous histo-pathological outcome measures for astrogliosis and microgliosis derived from the entire white matter. Results A spectrum of WMI was observed that ranged from diffuse non-necrotic lesions to more severe injury that comprised discrete foci of microscopic or macroscopic necrosis. Residual arterial pressure, oxygen content and blood glucose displayed a significant inverse association with WMI and lactate concentrations were directly related. Elevated glucose levels were the most significantly associated with less severe WMI. Conclusions Our results suggest that under conditions of hypoxemia and severe cephalic hypotension, WMI severity measured using unbiased immunohistochemical measurements correlated with several physiologic parameters, including glucose, which may be a useful marker of fetal response to hypoxia or provide protection against energy failure and more severe WMI.

Riddle, Art; Maire, Jennifer; Cai, Victor; Nguyen, Thuan; Gong, Xi; Hansen, Kelly; Grafe, Marjorie R.; Hohimer, A. Roger; Back, Stephen A.

2013-01-01

241

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 and…

Pavlova, Marina A.; Krageloh-Mann, Ingeborg

2013-01-01

242

White matter damage in frontotemporal lobar degeneration spectrum.  

PubMed

White matter (WM) tract damage was assessed in patients with the behavioral variant frontotemporal dementia (bvFTD) and the 3 primary progressive aphasia (PPA) variants and compared with the corresponding brain atrophy patterns. Thirteen bvFTD and 20 PPA patients were studied. Tract-based spatial statistics and voxel-based morphometry were used. Patients with bvFTD showed widespread diffusion tensor magnetic resonance imaging (DT MRI) abnormalities affecting most of the WM bilaterally. In PPA patients, WM damage was more focal and varied across the 3 syndromes: left frontotemporoparietal in nonfluent, left frontotemporal in semantic, and left frontoparietal in logopenic patients. In each syndrome, DT MRI changes extended beyond the topography of gray matter loss. Left uncinate damage was the best predictor of frontotemporal lobar degeneration diagnosis versus controls. DT MRI measures of the anterior corpus callosum and left superior longitudinal fasciculus differentiated bvFTD from nonfluent cases. The best predictors of semantic PPA compared with both bvFTD and nonfluent cases were diffusivity abnormalities of the left uncinate and inferior longitudinal fasciculus. This study provides insights into the similarities and differences of WM damage in bvFTD and PPA variants. DT MRI metrics hold promise to serve as early markers of WM integrity loss that only at a later stage may be detectable by volumetric measures. PMID:21988828

Agosta, F; Scola, E; Canu, E; Marcone, A; Magnani, G; Sarro, L; Copetti, M; Caso, F; Cerami, C; Comi, G; Cappa, S F; Falini, A; Filippi, M

2012-12-01

243

White Matter Aberrations in Prepubertal Estrogen-Naive Girls with Monosomic Turner Syndrome  

PubMed Central

Turner syndrome (TS) offers a unique opportunity to investigate associations among genes, the brain, and cognitive phenotypes. In this study, we used 3 complementary analyses of diffusion tensor imaging (DTI) data (whole brain, region of interest, and fiber tractography) and a whole brain volumetric imaging technique to investigate white matter (WM) structure in prepubertal, nonmosaic, estrogen-naive girls with TS compared with age and sex matched typically developing controls. The TS group demonstrated significant WM aberrations in brain regions implicated in visuospatial abilities, face processing, and sensorimotor and social abilities compared with controls. Extensive spatial overlap between regions of aberrant WM structure (from DTI) and regions of aberrant WM volume were observed in TS. Our findings indicate that complete absence of an X chromosome in young females (prior to receiving exogenous estrogen) is associated with WM aberrations in specific regions implicated in characteristic cognitive features of TS.

Barnea-Goraly, Naama; Marzelli, Matthew J.; Park, Yaena; Hong, David S.; Mimura, Masaru; Reiss, Allan L.

2012-01-01

244

Ultrastructural hippocampal and white matter alterations in mild cognitive impairment: a diffusion tensor imaging study.  

PubMed

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 is not clarified yet. Diffusion tensor imaging (DTI) reveals the ultrastructural integrity of cerebral white matter tracts. Therefore, it could detect pathological processes that modify tissue integrity in patients with MCI. In our prospective study, conventional and diffusion tensor MR scans were obtained from 14 patients with MCI, 19 patients with AD, and 10 healthy controls. Mean diffusivity (MD) and fractional anisotropy (FA) were measured in temporal, frontal, parietal and occipital white matter regions as well as in the corpus callosum (genu and splenium) and the hippocampus. MCI patients showed higher MD values in the left centrum semiovale (p = 0.013; right: p = 0.026), in the left temporal (p = 0.006), the right temporal (p = 0.014) and the left hippocampal (p = 0.002) region as compared to the control group. FA values of MCI patients and controls did not differ significantly in any region. Compared to controls, AD patients had increased MD values in the left centrum semiovale (p = 0.012), the left parietal (p = 0.001), the right parietal (p = 0.028), the left temporal (p = 0.018), the right temporal (p = 0.011) and the left hippocampal region (p = 0.002). Decreased FA values were measured in the left temporal area (p = 0.017) and in the left hippocampus (p = 0.031) in AD patients compared to controls. FA and MD values did not differ significantly between AD and MCI patients. Elevated MD values indicating brain tissue alterations in MCI patients were found in regions that are typically involved in early changes due to AD, particularly the left hippocampus. The sensitivity of distinguishing MCI patients from controls was 71.4% (with a specificity set at 80%). Therefore, the DTI technique validates the MCI concept, and diffusion tensor MR measurement can be a helpful tool to quantify MCI pathology in vivo. PMID:15087585

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

2004-01-01

245

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

246

Morphology of neurons in the white matter of the adult human neocortex  

Microsoft Academic Search

Neurons in the human cerebral cortical white matter below motor, visual, auditory and prefrontal orbital areas have been studied with the Golgi method, immunohistochemistry and diaphorase histochemistry. The majority of white matter neurons are pyramidal cells displaying the typical polarized, spiny dendritic system. The morphological variety includes stellate forms as well as bipolar pyramidal cells, and the expression of a

G. Meyer; P. Wahle; A. Castaneyra-Perdomo; R. Ferres-Torres

1992-01-01

247

A Voxel-Based Diffusion Tensor Imaging Study of White Matter in Bipolar Disorder  

Microsoft Academic Search

There is evidence from post-mortem and magnetic resonance imaging studies that hyperintensities, oligodendroglial abnormalities, and gross white matter volumetric alterations are involved in the pathophysiology of bipolar disorder. There is also functional imaging evidence for a defect in frontal cortico–subcortical pathways in bipolar disorder, but the white matter comprising these pathways has not been well investigated. Few studies have investigated

Katie Mahon; Jinghui Wu; Anil K Malhotra; Katherine E Burdick; Pamela DeRosse; Babak A Ardekani; Philip R Szeszko

2009-01-01

248

A DTI study of white matter microstructure in individuals at high genetic risk for schizophrenia  

Microsoft Academic Search

Structural brain developmental anomalies, particularly those in frontotemporal white matter pathways, may have a genetic component and place people at increased risk for schizophrenia. The current study employed Diffusion Tensor Imaging (DTI) to measure fractional anisotropy (FA) as a quantitative indicator of white matter integrity. We examined twenty-two participants at high genetic risk for schizophrenia (HR), 23 people with schizophrenia

Matthew J. Hoptman; Jay Nierenberg; Hilary C. Bertisch; Dean Catalano; Babak A. Ardekani; Craig A. Branch; Lynn E. DeLisi

2008-01-01

249

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 symptoms…

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

2007-01-01

250

Adrenomedullin Deficiency and Aging Exacerbate Ischemic White Matter Injury after Prolonged Cerebral Hypoperfusion in Mice  

PubMed Central

Adrenomedullin was originally isolated from pheochromocytoma cells and reduces insulin resistance by decreasing oxidative stress. White matter lesions induced by aging and hyperglycemia play a crucial role in cognitive impairment in poststroke patients. Here, we examine whether adrenomedullin deficiency and aging exacerbate ischemic white matter injury after prolonged cerebral hypoperfusion. Adrenomedullin heterozygous, wild-type young/aged mice were subjected to prolonged hypoperfusion. Prolonged cerebral hypoperfusion followed by immunohistochemical analysis was used to evaluate white matter injury. After prolonged hypoperfusion, white matter damage progressed in a time-dependent manner in AM+/? group compared with the wild-type group. The number of oligodendrocyte progenitor cells gradually increased after prolonged hypoperfusion, whereas oligodendrocytes decreased following a transient increase, but the ratio of increase was mild in the AM+/? group (P < 0.05). Oxidative stress was detected in oligodendrocytes, with a larger increase in the AM+/? group (P < 0.05). Aged mice showed the same tendency, but white matter damage was worse, especially in the aged AM+/? group. Our results demonstrated that white matter injury was increased in adrenomedullin deficiency, which induced oxidative stress. White matter injury was more exacerbated because of hyperglycemia in aged AM+/? group. Adrenomedullin may be an important target in the control of ischemic white matter injury.

Mitome-Mishima, Yumiko; Miyamoto, Nobukazu; Tanaka, Ryota; Shimosawa, Tatsuo; Oishi, Hidenori; Arai, Hajime; Hattori, Nobutaka; Urabe, Takao

2014-01-01

251

Diffusion tensor imaging of white matter pathology in the mouse brain  

PubMed Central

Diffusion tensor imaging has been increasingly used for studying white matter pathology in rodent models of neurological diseases. Here, applications of diffusion tensor imaging in detecting major and subtle white matter pathology in the mouse CNS are reviewed, followed by several technical details that may be helpful in designing studies that involve diffusion tensor imaging of rodent brain and spinal cord.

Zhang, Jiangyang

2011-01-01

252

Tractography reveals diffuse white matter abnormalities in Myotonic Dystrophy Type 1.  

PubMed

Cerebral involvement in Myotonic Dystrophy Type 1 (DM1) is well-established but not well characterized. This study applied new Diffusion Tensor Imaging (DTI) tractography to characterize white matter disturbance in adults with DM1. Forty-five participants with DM1 and 44 control participants had MRIs on a Siemens 3T TIM Trio scanner. Data were processed with TRActs Constrained by UnderLying Anatomy (TRACULA) and 7 tracts were evaluated. Bilateral disturbances in white matter integrity were seen in all tracts in participants with DM1 compared to controls. There were no right-left hemisphere differences. The resulting DTI metrics were correlated with cognitive functioning, particularly working memory and processing speed. Motor speed was not significantly correlated with white matter microstructural integrity and, thus, was not the core explanation for the working memory and processing speed findings. White matter integrity was correlated with important clinical variables including the muscular impairment rating scale (MIRS). CTG repeat length was moderately associated with white matter status in corticospinal tract and cingulum. Sleepiness (Epworth Sleepiness Scale) was moderately associated with white matter status in the superior longitudinal fasciculus and cingulum. Overall, the results add to an emerging literature showing widespread white matter disturbances in both early-onset and adult-onset DM1. Results suggest that further investigation of white matter pathology is warranted in DM1 and that non-invasive measures such as DTI have a potentially important clinical value in characterizing the status of individuals with DM1. PMID:24768314

Wozniak, Jeffrey R; Mueller, Bryon A; Lim, Kelvin O; Hemmy, Laura S; Day, John W

2014-06-15

253

Thymus Involution and Cerebral White Matter Damage in Extremely Low Gestational Age Neonates  

Microsoft Academic Search

Background: Among newborns who die, those who have cerebral white matter damage are more likely than others to have thymus involution and low thymus weights. Objective: We sought to evaluate in a population of preterm newborns who did not die if those who developed a cerebral white matter damage (as defined by an echolucency) are more likely than others to

Joshua David Kuban; Elizabeth N. Allred; Alan Leviton

2006-01-01

254

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

255

Cerebral White Matter Disease is Associated with Alzheimer Pathology in a Prospective Cohort  

PubMed Central

Background Although MRI detected white matter disease has been correlated with cognitive decline in the elderly, it is unclear whether white matter disease is primarily responsible for the cognitive deterioration or whether another process is common to white matter disease and dementia. Methods We examined the relationship between Alzheimer type brain pathology at autopsy and MRI detected cerebral white matter disease in 50 participants from the Baltimore Longitudinal Study of Aging (BLSA) Autopsy Program, a prospective study of aging which includes detailed cognitive assessments. Results White matter disease was quantitated in pre- and postmortem MRI scans using the Cardiovascular Health Study (CHS) criteria in a blinded fashion. We found that several measures of Alzheimer disease (AD) pathology including CERAD score, Braak score and a composite AD pathology score, along with hypertension, were significantly associated with CHS white matter score using univariate and multivariate ordinal regression. In contrast, amyloid angiopathy was not independently related to with CHS score. While a clinical diagnosis of dementia was associated with CHS score in univariate analysis, the association disappeared after accounting for AD pathology. Conclusion Alzheimer’s pathology at autopsy is associated with MRI detected cerebral white matter disease. This relationship may explain, in part, the association between cerebral white matter disease and cognitive decline in the elderly.

Moghekar, Abhay; Kraut, Michael; Elkins, Wendy; Troncoso, Juan; Zonderman, Alan B.; Resnick, Susan M; OBrien, Richard J

2012-01-01

256

White matter tracts in first-episode psychosis: A DTI tractography study of the uncinate fasciculus  

Microsoft Academic Search

A model of disconnectivity involving abnormalities in the cortex and connecting white matter pathways may explain the symptoms and cognitive abnormalities of schizophrenia. Recently, diffusion imaging tractography has made it possible to study white matter pathways in detail, and we present here a study of patients with first-episode psychosis using this technique. We studied the uncinate fasciculus (UF), the largest

Gary Price; Mara Cercignani; Geoffrey J. M. Parker; Daniel R. Altmann; Thomas R. E. Barnes; Gareth J. Barker; Eileen M. Joyce; Maria A. Ron

2008-01-01

257

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

Microsoft Academic Search

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

Thomas R Barrick; Chris A Clark

2004-01-01

258

Diffusion tractography based group mapping of major white-matter pathways in the human brain  

Microsoft Academic Search

Tractography uses diffusion tensor imaging data to trace white matter pathways in vivo within the brain. We have constructed group maps that represent three major white matter tracts—the anterior callosal fibers, optic radiations, and pyramidal tracts—in a group of 21 volunteers. For each individual tract the fast marching tractography (FMT) algorithm was used to generate a VSC (voxel scale connectivity)

O Ciccarelli; A. T Toosy; G. J. M Parker; C. A. M Wheeler-Kingshott; G. J Barker; D. H Miller; A. J Thompson

2003-01-01

259

Quantifying cerebellum grey matter and white matter perfusion using pulsed arterial spin labeling.  

PubMed

To facilitate quantification of cerebellum cerebral blood flow (CBF), studies were performed to systematically optimize arterial spin labeling (ASL) parameters for measuring cerebellum perfusion, segment cerebellum to obtain separate CBF values for grey matter (GM) and white matter (WM), and compare FAIR ASST to PICORE. Cerebellum GM and WM CBF were measured with optimized ASL parameters using FAIR ASST and PICORE in five subjects. Influence of volume averaging in voxels on cerebellar grey and white matter boundaries was minimized by high-probability threshold masks. Cerebellar CBF values determined by FAIR ASST were 43.8 ± 5.1?mL/100?g/min for GM and 27.6 ± 4.5?mL/100?g/min for WM. Quantitative perfusion studies indicated that CBF in cerebellum GM is 1.6 times greater than that in cerebellum WM. Compared to PICORE, FAIR ASST produced similar CBF estimations but less subtraction error and lower temporal, spatial, and intersubject variability. These are important advantages for detecting group and/or condition differences in CBF values. PMID:24949416

Li, Xiufeng; Sarkar, Subhendra N; Purdy, David E; Briggs, Richard W

2014-01-01

260

Influences of lobar gray matter and white matter lesion load on cognition and mood  

PubMed Central

Depressed mood is a frequent co-morbidity of dementia suggesting that they might share a common neuropathological substrate. Gray matter (GM) atrophy and white matter lesions (WML) have been described in both conditions. Our aims were to determine the relationship of GM and WML with cognition and depressed mood in the same population. Structural brain images were obtained from 42 controls, 20 Alzheimer’s disease (AD) patients and 32 subjects with cognitive impairment/dementia due to subcortical cerebrovascular disease (vascCIND/IVD) and segmented to obtain lobar GM, white matter and WML volumes. Lobar WML had a negative effect on GM in all lobes in controls, on frontal, parietal and occipital GM in AD and on frontal GM in vascCIND/IVD. Frontal, temporal and hippocampal GM were associated with cognitive functions and frontal WML load with depressed mood. Cognitive function is associated with GM atrophy and depressed mood is associated with frontal WML. This indicates that although both often occur together depressed mood and cognitive impairment are caused by different pathological correlates.

Mueller, Susanne G.; Mack, Wendy J; Mungas, Dan; Kramer, Joel H.; Cardenas-Nicolson, Valerie; Lavretsky, Helen; Greene, Maxwell; Schuff, Norbert; Chui, Helena C.; Weiner, Michael W.

2009-01-01

261

Quantifying Cerebellum Grey Matter and White Matter Perfusion Using Pulsed Arterial Spin Labeling  

PubMed Central

To facilitate quantification of cerebellum cerebral blood flow (CBF), studies were performed to systematically optimize arterial spin labeling (ASL) parameters for measuring cerebellum perfusion, segment cerebellum to obtain separate CBF values for grey matter (GM) and white matter (WM), and compare FAIR ASST to PICORE. Cerebellum GM and WM CBF were measured with optimized ASL parameters using FAIR ASST and PICORE in five subjects. Influence of volume averaging in voxels on cerebellar grey and white matter boundaries was minimized by high-probability threshold masks. Cerebellar CBF values determined by FAIR ASST were 43.8 ± 5.1?mL/100?g/min for GM and 27.6 ± 4.5?mL/100?g/min for WM. Quantitative perfusion studies indicated that CBF in cerebellum GM is 1.6 times greater than that in cerebellum WM. Compared to PICORE, FAIR ASST produced similar CBF estimations but less subtraction error and lower temporal, spatial, and intersubject variability. These are important advantages for detecting group and/or condition differences in CBF values.

Li, Xiufeng; Sarkar, Subhendra N.; Purdy, David E.; Briggs, Richard W.

2014-01-01

262

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

263

Attention-network specific alterations of structural connectivity in the undamaged white matter in acute neglect.  

PubMed

Visual neglect results from dysfunction within the spatial attention network. The structural connectivity in undamaged brain tissue in neglect has barely been investigated until now. In the present study, we explored the microstructural white matter characteristics of the contralesional hemisphere in relation to neglect severity and recovery in acute stroke patients. We compared age-matched healthy subjects and three groups of acute stroke patients (9?±?0.5 days after stroke): (i) patients with nonrecovered neglect (n?=?12); (ii) patients with rapid recovery from initial neglect (within the first week post-stroke, n?=?7), (iii) stroke patients without neglect (n?=?17). We analyzed the differences between groups in grey and white matter density and fractional anisotropy (FA) and used fiber tracking to identify the affected fibers. Patients with nonrecovered neglect differed from those with rapid recovery by FA-reduction in the left inferior parietal lobe. Fibers passing through this region connect the left-hemispheric analogues of the ventral attention system. Compared with healthy subjects, neglect patients with persisting neglect had FA-reduction in the left superior parietal lobe, optic radiation, and left corpus callosum/cingulum. Fibers passing through these regions connect centers of the left dorsal attention system. FA-reduction in the identified regions correlated with neglect severity. The study shows for the first time white matter changes within the spatial attention system remote from the lesion and correlating with the extent and persistence of neglect. The data support the concept of neglect as disintegration within the whole attention system and illustrate the dynamics of structural-functional correlates in acute stroke. Hum Brain Mapp 35:4678-4692, 2014. © 2014 Wiley Periodicals, Inc. PMID:24668692

Umarova, Roza M; Reisert, Marco; Beier, Tanja-Ute; Kiselev, Valerij G; Klöppel, Stefan; Kaller, Christoph P; Glauche, Volkmar; Mader, Irina; Beume, Lena; Hennig, Jürgen; Weiller, Cornelius

2014-09-01

264

Widespread reductions of white matter integrity in patients with long-term remission of Cushing's disease  

PubMed Central

Background Hypercortisolism leads to various physical, psychological and cognitive symptoms, which may partly persist after the treatment of Cushing's disease. The aim of the present study was to investigate abnormalities in white matter integrity in patients with long-term remission of Cushing's disease, and their relation with psychological symptoms, cognitive impairment and clinical characteristics. Methods In patients with long-term remission of Cushing's disease (n = 22) and matched healthy controls (n = 22) we examined fractional anisotropy (FA) values of white matter in a region-of-interest (ROI; bilateral cingulate cingulum, bilateral hippocampal cingulum, bilateral uncinate fasciculus and corpus callosum) and the whole brain, using 3 T diffusion tensor imaging (DTI) and a tract-based spatial statistics (TBSS) approach. Psychological and cognitive functioning were assessed with validated questionnaires and clinical severity was assessed using the Cushing's syndrome Severity Index. Results The ROI analysis showed FA reductions in all of the hypothesized regions, with the exception of the bilateral hippocampal cingulum, in patients when compared to controls. The exploratory whole brain analysis showed multiple regions with lower FA values throughout the brain. Patients reported more apathy (p = .003) and more depressive symptoms (p < .001), whereas depression symptom severity in the patient group was negatively associated with FA in the left uncinate fasciculus (p < 0.05). Post-hoc analyses showed increased radial and mean diffusivity in the patient group. Conclusion Patients with a history of endogenous hypercortisolism in present remission show widespread changes of white matter integrity in the brain, with abnormalities in the integrity of the uncinate fasciculus being related to the severity of depressive symptoms, suggesting persistent structural effects of hypercortisolism.

van der Werff, Steven J.A.; Andela, Cornelie D.; Nienke Pannekoek, J.; Meijer, Onno C.; van Buchem, Mark A.; Rombouts, Serge A.R.B.; van der Mast, Roos C.; Biermasz, Nienke R.; Pereira, Alberto M.; van der Wee, Nic J.A.

2014-01-01

265

White Matter Hyperintensities, Exercise and Improvement in Gait Speed: Does the Type of Gait Rehabilitation Matter?  

PubMed Central

Background and Objectives White matter hyperintensities (WMH) on brain MRI are associated with cognitive and mobility impairment in older adults. We examined whether WMH in tracts in older adults with mobility impairment are linked to outcomes of gait rehabilitation interventions. Design A 12-week randomized controlled single-blind trial. Setting University-based mobility research laboratory. Participants Ambulatory adults aged 65 and older with mobility impairment. Intervention A conventional gait intervention focusing on walking, endurance, balance, and strength (WEBS, n=21) compared to a task-oriented intervention focused on timing and coordination of gait (TC, n=23). Measurements We measured self-paced gait speed over an instrumented walkway, pre and post intervention, and quantified WMH and brain volumes on pre-intervention brain MRI using an automated segmentation process. We overlaid a white matter tract atlas on the segmented images to measure tract WMH volumes and normalized WMH volumes to total brain volume. Aggregate WMH volumes in all white matter tracts and individual WMH volumes in specific longitudinal tracts (the superior longitudinal fasciculus, inferior longitudinal fasciculus and the fronto-occipital fasciculus) and cingulum were obtained. Results Gait speed gains in the TC group were of the same magnitude, independent of the WMH volume measures in all except the cingulum. However, in the WEBS group, gain in gait speed was smaller with greater overall tract WMH volumes (P<0.001) and with greater WMH volume in the three longitudinal tracts (P< 0.001 to 0.025). Conclusion Gains in gait speed with two types of gait rehabilitation are associated with individual differences in WMH. Task-oriented therapy that targets timing and coordination of gait may particularly benefit older adults with WMH in brain tracts that influence gait and cognition.

Nadkarni, Neelesh K.; Studenski, Stephanie A.; Perera, Subashan; Rosano, Caterina; Aizenstein, Howard J.; Brach, Jennifer S.; VanSwearingen, Jessie M.

2013-01-01

266

Dark matter in the MSSM golden region  

SciTech Connect

Dark matter is examined within the 'golden region' of the minimal supersymmetric standard model. This region satisfies experimental constraints, including a lower bound on the Higgs mass of 114 GeV, and minimizes fine-tuning of the Z boson mass. Here we impose additional constraints (particularly due to experimental bounds on b{yields}s{gamma}). Then we find the properties of the dark matter in this region. Neutralinos with a relic density that provides the amount of dark matter required by cosmological data are shown to consist of a predominant gaugino (rather than Higgsino) fraction. In addition, the U(1){sub Y} gaugino mass parameter must satisfy M{sub 1} < or approx. 300 GeV.

Kasahara, Junya; Gondolo, Paolo [Department of Physics, University of Utah, 115 South 1400 East, Suite 201, Salt Lake City, Utah 84112-0830 (United States); Freese, Katherine [Michigan Center for Theoretical Physics, Physics Department, University of Michigan, Ann Arbor, Michigan 48109 (United States)

2009-02-15

267

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

2013-06-01

268

Individual Differences in Distinct Components of Attention are Linked to Anatomical Variations in Distinct White Matter Tracts  

PubMed Central

Inter-subject variations in white matter tract properties are known to correlate with individual differences in performance in cognitive domains such as attention. The specificity of such linkages, however, is largely unexplored at the level of specific component operations of attention associated with distinct anatomical networks. This study examines individual performance variation within three functional components of attention – alerting, orienting, and conflict processing – identified by the Attention Network Task (ANT), and relates each to inter-subject variation in a distinct set of white matter tract regions. Diffusion tensor imaging data collected at 3T was used to calculate average fractional anisotropy within a set of individualized a priori defined regions of interest using the Reproducible Objective Quantification Scheme (ROQS) (Niogi and McCandliss, 2006; Niogi et al., 2007). Results demonstrate three functionally distinct components of attention that each correlate distinctly with three white matter tract regions. Structure–function correlations were found between alerting and the anterior limb of the internal capsule, orienting and the splenium of the corpus callosum, and conflict and the anterior corona radiata. A multiple regression/dissociation analysis demonstrated a triple dissociation between these three structure-function relationships that provided evidence of three anatomically and functionally separable networks. These results extend previous findings from functional imaging and lesion studies that suggest these three components of attention are subserved by dissociable networks, and suggest that variations in white matter tract microstructure may modulate the efficiency of these cognitive processes in highly specific ways.

Niogi, Sumit; Mukherjee, Pratik; Ghajar, Jamshid; McCandliss, Bruce D.

2009-01-01

269

White Matter Abnormalities and Working Memory Impairment in Systemic Lupus Erythematosus  

PubMed Central

Objective/Background Many patients with systemic lupus erythematosus (SLE) have working memory deficits. Few studies have evaluated working memory performance and neurometabolite profile using magnetic resonance spectroscopy (MRS) in SLE. Methods We gave the Paced Auditory Serial Addition Test (PASAT), a measure of working memory, to 73 patients with SLE. We calculated total score, dyads, chunking, and cognitive fatigue. Using MRS, we determined the ratio of choline to creatine (Ch/Cr) in normal-looking right and left frontal lobe white matter. Results Twenty-nine percent of patients showed impaired working memory on the PASAT. Total PASAT score inversely correlated with right and left frontal white matter Ch/Cr. Left frontal white matter Ch/Cr correlated with percent chunking and inversely correlated with total and percent of dyads. Right frontal white matter Ch/Cr correlated with percent chunking and inversely correlated with total and percent dyads. There was no relationship between cognitive fatigue and either left or right frontal white matter Ch/Cr. Longer disease duration was associated with higher left frontal white matter Ch/Cr. Correlations remained significant between left frontal white matter Ch/Cr and total PASAT score and total dyads when disease duration was considered. Conclusions Patients with SLE were impaired on the PASAT. Lower total PASAT score and fewer dyads correlated with higher left frontal microstructural white matter damage, while cognitive fatigue did not. This pattern suggests that early white matter damage interferes with working memory in SLE and provides further insight into the neurobiological basis of mild cognitive dysfunction related to microstructural white matter injury.

Kozora, Elizabeth; Arciniegas, David B.; Duggan, Emily; West, Sterling; Brown, Mark; Filley, Christopher M.

2013-01-01

270

A universal scaling law between gray matter and white matter of cerebral cortex  

PubMed Central

Neocortex, a new and rapidly evolving brain structure in mammals, has a similar layered architecture in species over a wide range of brain sizes. Larger brains require longer fibers to communicate between distant cortical areas; the volume of the white matter that contains long axons increases disproportionally faster than the volume of the gray matter that contains cell bodies, dendrites, and axons for local information processing, according to a power law. The theoretical analysis presented here shows how this remarkable anatomical regularity might arise naturally as a consequence of the local uniformity of the cortex and the requirement for compact arrangement of long axonal fibers. The predicted power law with an exponent of 4/3 minus a small correction for the thickness of the cortex accurately accounts for empirical data spanning several orders of magnitude in brain sizes for various mammalian species, including human and nonhuman primates.

Zhang, Kechen; Sejnowski, Terrence J.

2000-01-01

271

White matter damage in primary progressive aphasias: a diffusion tensor tractography study  

PubMed Central

Primary progressive aphasia is a clinical syndrome that encompasses three major phenotypes: non-fluent/agrammatic, semantic and logopenic. These clinical entities have been associated with characteristic patterns of focal grey matter atrophy in left posterior frontoinsular, anterior temporal and left temporoparietal regions, respectively. Recently, network-level dysfunction has been hypothesized but research to date has focused largely on studying grey matter damage. The aim of this study was to assess the integrity of white matter tracts in the different primary progressive aphasia subtypes. We used diffusion tensor imaging in 48 individuals: nine non-fluent, nine semantic, nine logopenic and 21 age-matched controls. Probabilistic tractography was used to identify bilateral inferior longitudinal (anterior, middle, posterior) and uncinate fasciculi (referred to as the ventral pathway); and the superior longitudinal fasciculus segmented into its frontosupramarginal, frontoangular, frontotemporal and temporoparietal components, (referred to as the dorsal pathway). We compared the tracts’ mean fractional anisotropy, axial, radial and mean diffusivities for each tract in the different diagnostic categories. The most prominent white matter changes were found in the dorsal pathways in non-fluent patients, in the two ventral pathways and the temporal components of the dorsal pathways in semantic variant, and in the temporoparietal component of the dorsal bundles in logopenic patients. Each of the primary progressive aphasia variants showed different patterns of diffusion tensor metrics alterations: non-fluent patients showed the greatest changes in fractional anisotropy and radial and mean diffusivities; semantic variant patients had severe changes in all metrics; and logopenic patients had the least white matter damage, mainly involving diffusivity, with fractional anisotropy altered only in the temporoparietal component of the dorsal pathway. This study demonstrates that both careful dissection of the main language tracts and consideration of all diffusion tensor metrics are necessary to characterize the white matter changes that occur in the variants of primary progressive aphasia. These results highlight the potential value of diffusion tensor imaging as a new tool in the multimodal diagnostic evaluation of primary progressive aphasia.

Galantucci, Sebastiano; Tartaglia, Maria Carmela; Wilson, Stephen M.; Henry, Maya L.; Filippi, Massimo; Agosta, Federica; Dronkers, Nina F.; Henry, Roland G.; Ogar, Jennifer M.; Miller, Bruce L.

2011-01-01

272

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

2013-10-01

273

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

274

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

275

White matter microstructural changes in psychogenic erectile dysfunction patients.  

PubMed

Brain dysfunction in erectile dysfunction (ED) has been identified by multiple neuroimaging studies. A recent MRI study indicated grey matter alterations in ED patients. This study aims to investigate the microstructural changes of cerebral white matter (WM) in psychological ED patients and their possible correlations with clinical variables. Twenty-seven psychological ED patients and 27 healthy subjects (HS) were included and underwent a magnetic resonance (MR) diffusion tensor imaging (DTI) scan. The tract-based spatial statistics were employed to identify the WM structure alterations in psychological ED patients. The multiple DTI-derived indices' [fractional anisotropy (FA), axial diffusivity (AD) and mean diffusivity (MD)] correlations with the symptoms and their durations, respectively, were analysed. The IIEF-5, quality of erection questionnaire (QEQ) and the self-esteem and relationship (SEAR) questionnaire were used to assess the symptoms of psychological ED patients. Compared with HS, the psychological ED patients showed increased FA values, reduced MD values and reduced AD values in multiple WM tracts including the corpus callosum (genu, body and splenium), corticospinal tract, internal capsule, corona radiata, external capsule and superior longitudinal fasciculus (p < 0.05, threshold-free cluster enhancement corrected). Both of the IIEF scores and QEQ scores of ED patients showed a significantly negative correlation with the average FA values, and positive correlation with average AD values and MD values in the splenium of the corpus callosum (p < 0.05). The results provided preliminary evidence of WM microstructural changes in patients with psychological ED. The morphological alterations in the splenium of the corpus callosum were related to the symptom severity. PMID:24711250

Zhang, P; Liu, J; Li, G; Pan, J; Li, Z; Liu, Q; Qin, W; Dong, M; Sun, J; Huang, X; Wu, T; Chang, D

2014-05-01

276

Human adult white matter progenitor cells are multipotent neuroprogenitors similar to adult hippocampal progenitors.  

PubMed

Adult neural progenitor cells (aNPC) are a potential autologous cell source for cell replacement in neurologic diseases or for cell-based gene therapy of neurometabolic diseases. Easy accessibility, long-term expandability, and detailed characterization of neural progenitor cell (NPC) properties are important requisites for their future translational/clinical applications. aNPC can be isolated from different regions of the adult human brain, including the accessible subcortical white matter (aNPCWM), but systematic studies comparing long-term expanded aNPCWM with aNPC from neurogenic brain regions are not available. Freshly isolated cells from subcortical white matter and hippocampus expressed oligodendrocyte progenitor cell markers such as A2B5, neuron-glial antigen 2 (NG2), and oligodendrocyte transcription factor 2 (OLIG2) in ?20% of cells but no neural stem cell (NSC) markers such as CD133 (Prominin1), Nestin, SOX2, or PAX6. The epidermal growth factor receptor protein was expressed in 18% of aNPCWM and 7% of hippocampal aNPC (aNPCHIP), but only a small fraction of cells, 1 of 694 cells from white matter and 1 of 1,331 hippocampal cells, was able to generate neurospheres. Studies comparing subcortical aNPCWM with their hippocampal counterparts showed that both NPC types expressed mainly markers of glial origin such as NG2, A2B5, and OLIG2, and the NSC/NPC marker Nestin, but no pericyte markers. Both NPC types were able to produce neurons, astrocytes, and oligodendrocytes in amounts comparable to fetal NSC. Whole transcriptome analyses confirmed the strong similarity of aNPCWM to aNPCHIP. Our data show that aNPCWM are multipotent NPC with long-term expandability similar to NPC from hippocampus, making them a more easily accessible source for possible autologous NPC-based treatment strategies. PMID:24558163

Lojewski, Xenia; Hermann, Andreas; Wegner, Florian; Araúzo-Bravo, Marcos J; Hallmeyer-Elgner, Susanne; Kirsch, Matthias; Schwarz, Johannes; Schöler, Hans R; Storch, Alexander

2014-04-01

277

Parahippocampal white matter volume predicts Alzheimer's disease risk in cognitively normal old adults.  

PubMed

An in vivo marker of the underlying pathology in Alzheimer's disease (AD) is atrophy in select brain regions detected with quantitative magnetic resonance imaging (MRI). Although gray matter changes have been documented to be predictive of cognitive decline culminating in AD among healthy older adults, very little attention has been given to alterations in white matter as a possible MRI biomarker predictive of AD. In this investigation, we examined parahippocampal white matter (PWM) volume derived from baseline MRI scans in 2 independent samples of 65 cognitively normal older adults, followed longitudinally, to determine if it was predictive of AD risk. The average follow-up period for the 2 samples was 8.5 years. Comparisons between the stable participants (N = 50) and those who declined to AD (N = 15) over time revealed a significant difference in baseline PWM volume (p < 0.001). Furthermore, baseline PWM volume was predictive not only of time to AD (hazard ratio = 3.1, p < 0.05), but also of baseline episodic memory performance (p = 0.041). These results demonstrate that PWM atrophy provides a sensitive MRI biomarker of AD dementia risk among those with normal cognitive function. PMID:24656833

Stoub, Travis R; Detoledo-Morrell, Leyla; Dickerson, Bradford C

2014-08-01

278

Modeling blast induced neurotrauma in isolated spinal cord white matter.  

PubMed

Blast-induced neurotrauma (BINT) is a common injury associated with the present military conflicts. Exposure to the shock-wave produced from exploding ordnances leads to significant neurological deficits throughout the brain and spinal cord. Prevention and treatment of this injury requires an appropriate understanding of the mechanisms governing the neurological response. Here, we present a novel ex-vivo BINT model where an isolated section of guinea pig spinal cord white matter is exposed to the shock-wave produced from a small scale explosive event. Additionally, we define the relationship between shock-wave impact, tissue deformation and resulting anatomical and functional deficits associated with BINT. Our findings suggest an inverse relationship between the magnitude of the shock-wave overpressure and the degree of functional deficits using a double sucrose gap recording chamber. Similar correlations are drawn between overpressure and degree of anatomical damage of neuronal processes using a dye-exclusion assay. The following approach is expected to significantly contribute to the detection, mitigation and eventual treatment of BINT. PMID:20703730

Connell, Sean; Ouyang, Hui; Shi, Riyi

2011-10-01

279

Fiber-to-bundle registration of white matter tracts  

NASA Astrophysics Data System (ADS)

Magnetic resonance diffusion tensor imaging (DTI) is being widely used to reconstruct brain white matter (WM) fiber tracts. For further characterization of the tracts, the fibers with similar courses often need to be grouped into a fiber bundle that corresponds to certain underlying WM anatomic structure. In addition, the alignments of fibers from different studies are often desirable for bundle comparisons and group analysis. In this work, a novel registration algorithm based on fiber-to-bundle matching was proposed to address the above two needs. Using an Expectation Maximization (EM) algorithm, the proposed method is capable of estimating a Thin-Plate- Spline transformation that optimally aligns whole-brain target fiber sets with a reference bundle model. Based on the resulting transformations, the fibers from different target datasets can all be warped into the reference coordinate system for comparisons and group analysis. The fibers can be further automatically labeled according to their similarity to the reference model. The algorithm was evaluated with eight human brain DTI data volumes acquired in vivo at 3T. After registration, the warped target bundles exhibit good similarity to the reference bundles. Quantitative experiments further demonstrated that the detected target bundles agree with ground truth obtained by manual segmentation at a sub-voxel accuracy.

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

2009-02-01

280

Social reward dependence and brain white matter microstructure.  

PubMed

People show consistent differences in their cognitive and emotional responses to environmental cues, manifesting, for example, as variability in social reward processing and novelty-seeking behavior. However, the neurobiological foundation of human temperament and personality is poorly understood. A likely hypothesis is that personality traits rely on the integrity and function of distributed neurocircuitry. In this diffusion tensor imaging (DTI) study, this hypothesis was tested by examining the associations between reward dependence (RD) and novelty seeking (NS), as measured by Cloninger's Temperament and Character Inventory, and fractional anisotropy (FA) and mean diffusivity (MD) as DTI-derived indices of white matter (WM) microstructure across the brain. The results supported the hypothesis. RD was associated with WM architecture coherence as indicated by a negative correlation between RD and FA in frontally distributed areas including pathways connecting important constituents of reward-related neurocircuitry. The associations between RD and FA could not be explained by age, sex, alcohol consumption, or trait anxiety. In contrast, no effects were observed for NS. These findings support the theory that WM fiber tract properties modulate individual differences in social reward processing. PMID:22156472

Bjørnebekk, Astrid; Westlye, Lars T; Fjell, Anders M; Grydeland, Håkon; Walhovd, Kristine B

2012-11-01

281

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

282

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

2013-06-01

283

White Matter Hyperintensity Burden and Susceptibility to Cerebral Ischemia  

PubMed Central

Background and Purpose White matter hyperintensity (WMH) burden increases risk of ischemic stroke; furthermore, it predicts infarct growth in acute cerebral ischemia. We hypothesized that WMH would be less severe in patients with transient ischemic attack (TIA), as compared to those with acute ischemic stroke (AIS) and completed infarct. Methods Cases (TIA, n=30) and controls (AIS, n=120) were selected from an ongoing longitudinal cohort study of patients with stroke and matched for age, gender, and race/ethnicity. All subjects had brain MRI within 48 hours of presentation to evaluate for acute cerebral ischemia. WMH burden on MRI was quantified using a validated computer-assisted program with high inter-rater reliability. Results Median WMH in individuals with TIA was 3.7 cm3 (IQR 1.5 - 8.33cm3) compared to 6.9 cm3 (IQR 3.1 - 11.9 cm3) in AIS (p<0.04). In multivariable analysis, the odds of completed infarct were higher (OR 2.19, 95% CI 1.27 - 3.77, p<0.005) in subjects with larger volumes of WMH. Conclusions WMH burden was significantly less in subjects with TIA as opposed to ischemic stroke. These data provide further evidence to support a detrimental role of WMH burden on the capacity of cerebral tissue to survive acute ischemia.

Rost, Natalia S; Fitzpatrick, Kaitlin; Biffi, Alessandro; Kanakis, Allison; Devan, William; Anderson, Christopher D.; Cortellini, Lynelle; Furie, Karen L; Rosand, Jonathan

2010-01-01

284

White Matter Hyperintensities and Dynamics of Postural Control  

PubMed Central

Background White matter hyperintensities (WMHs) on MRI have been associated with age, cardiovascular risk factors, and falls in the elderly. This study evaluated the relationship between WMHs and dynamics of postural control in older adults without history of falls. Methods We studied 76 community living subjects without history of falls (age 64.5±7.3 yrs). Brain and WMHs volume calculations and clinical rating were done on FLAIR and MP-RAGE MR images on 3 Tesla. Balance was assessed from the center of pressure displacement using the force platform during 3 minutes of quiet standing using traditional and dynamic measures (using stabilogram-diffusion analysis). Gait speed was measured from 12 minute walk. Results Age-adjusted periventricular and focal WMHs were associated with changes in certain dynamic balance measures, including reduced range of postural sway in anteroposterior direction (fronto-temporal WMHs, p=0.045; parieto-occipital WMHs, p=0.009) and more irregular longterm mediolateral fluctuations (p=0.046). Normal walking speed was not affected by WMHs. Conclusions Periventricul and focal WMHs affect long-term dynamics of postural control, which requires engagement of feedback mechanisms, and may contribute to mobility decline in the elderly.

Novak, Vera; Haertle, Mareile; Zhao, Peng; Hu, Kun; Munshi, Medha; Novak, Peter; Abduljalil, Amir; Alsop, David

2009-01-01

285

Neurocognitive deficits in medulloblastoma survivors and white matter loss.  

PubMed

Although previous studies have documented a significant risk of intellectual loss after treatment for childhood medulloblastoma (MED), the pathophysiology underlying this process is poorly understood. The purpose of this study was to test the hypotheses that (1) patients treated for MED in childhood have reduced volumes of normal white matter (NWM) related to their treatment with craniospinal irradiation with or without chemotherapy, and (2) deficits in NWM among patients surviving MED can at least partially explain deficits in their intellectual performance. Eighteen pediatric patients previously treated for MED were matched on the basis of age at the time of evaluation to 18 patients previously treated for low-grade posterior fossa tumors with surgery alone (mean difference, 3.7 months). Evaluations were conducted with age-appropriate neurocognitive testing and quantitative magnetic resonance imaging by using a novel automated segmentation and classification algorithm constructed from a hybrid neural network. Patients treated for MED had significantly less NWM (p < 0.01) and significantly lower Full-Scale IQ values than those treated for low-grade tumors (mean, 82.1 vs 92.9). In addition, NWM had a positive and statistically significant association with Full-Scale IQ among the patients treated for MED. We conclude that irradiation- or chemotherapy-induced destruction of NWM can at least partially explain intellectual and academic achievement deficits among MED survivors. PMID:10589535

Mulhern, R K; Reddick, W E; Palmer, S L; Glass, J O; Elkin, T D; Kun, L E; Taylor, J; Langston, J; Gajjar, A

1999-12-01

286

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

287

Identity Form Matters: White Racial Identity and Attitudes Toward Diversity  

Microsoft Academic Search

Previous research has drawn mixed conclusions regarding the relationship between White racial identity and attitudes toward diversity. We propose that identity form may help to disambiguate this relationship. In the present study, White participants wrote brief essays and were grouped based on their exhibition of one of three White identity forms: power-cognizant, prideful, or weakly identified. These groups were then

Matt J. Goren; Victoria C. Plaut

2012-01-01

288

Identity form matters: White racial identity and attitudes toward diversity  

Microsoft Academic Search

Previous research has drawn mixed conclusions regarding the relationship between White racial identity and attitudes toward diversity. We propose that identity form may help to disambiguate this relationship. In the present study, White participants wrote brief essays and were grouped based on their exhibition of one of three White identity forms: power-cognizant, prideful, or weakly identified. These groups were then

Matt J. Goren; Victoria C. Plaut

2011-01-01

289

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

290

Automatic clustering of white matter fibers based on symbolic sequence analysis  

NASA Astrophysics Data System (ADS)

Fiber clustering is a very important step towards tract-based, quantitative analysis of white matter via diffusion tensor imaging (DTI). This work proposes a new computational framework for white matter fiber clustering based on symbolic sequence analysis method. We first perform brain tissue segmentation on the DTI image using a multi-channel fusion method and parcellate the whole brain into anatomically labeled regions via a hybrid volumetric and surface warping algorithm. Then, we perform standard fiber tractography on the DTI image and encode each tracked fiber by a sequence of labeled brain regions. Afterwards, the similarity between any pair of anatomically encoded fibers is defined as the similarity of symbolic sequences, which is a well-studied problem in the bioinformatics domain such as is used for gene and protein symbolic sequences comparisons. Finally, the normalized graph cut algorithm is applied to cluster the fibers into bundles based on the above defined similarities between any pair of fibers. Our experiments show promising results of the proposed fiber clustering framework.

Ge, Bao; Guo, Lei; Li, Kaiming; Li, Hai; Faraco, Carlos; Zhao, Qun; Miller, Stephen; Liu, Tianming

2010-03-01

291

A crucial role for white matter alterations in interference control problems of very preterm children.  

PubMed

Background:Attention problems are among the most prominent behavioral deficits reported in very preterm children (below 32?wk of gestation) at school age. In this study, we aimed to elucidate the brain abnormalities underlying attention problems in very preterm children by investigating the role of abnormalities in white and gray brain matter during interference control, using functional magnetic resonance imaging (fMRI)-guided probabilistic diffusion tensor tractography.Methods:Twenty-nine very preterm children (mean (SD) age: 8.6 (0.3) y), and 47 term controls (mean (SD) age: 8.7 (0.5) y), performed a fMRI version of the Eriksen Flanker task measuring interference control.Results:Very preterm children showed slower reaction times than term controls when interfering stimuli were presented, indicating poorer interference control. Very preterm children and term controls did not differ in mean activation of the cortical regions involved in interference control. However, impaired fractional anisotropy (FA) was found in very preterm children in specifically those fiber tracts that innervate the cortical regions involved in interference control. Lower FA was related to poorer interference control in very preterm children.Conclusion:White matter alterations have a crucial role in the interference control problems of very preterm children at school age. PMID:24695275

de Kieviet, Jorrit F; Heslenfeld, Dirk J; Pouwels, Petra J W; Lafeber, Harrie N; Vermeulen, R Jeroen; van Elburg, Ruurd M; Oosterlaan, Jaap

2014-06-01

292

Changes in white matter integrity follow excitatory rTMS treatment of post-stroke aphasia  

PubMed Central

Purpose In this study, we examine whether an excitatory repetitive transcranial magnetic stimulation (rTMS) protocol called intermittent theta burst stimulation (iTBS) applied to the affected left hemisphere leads to changes in white matter fractional anisotropy (FA). Methods Diffusion tensor imaging (DTI) data were collected in 8 aphasic stroke patients before and after 10 daily iTBS treatments. Alignment of structural and DTI data and derivation of diffusion index maps were performed using Analysis of Functional NeuroImages software followed by Tract-Based Spatial Statistics using FMRIB Software Library. Paired t-tests were performed to compare pre- to post-rTMS changes in FA. Results There were significant (p<0.001) left-hemispheric FA increases near the inferior and superior frontal gyri and anterior corpus callosum. FA also increased in the right midbrain and bilaterally near temporal, parietal and posterior cingulate regions. FA decreased bilaterally near the fusiform gyrus and in left cerebellum. Conclusions Overall, left-hemispheric regions that showed increased FA corresponded to areas previously shown to have increases in fMRI language activation after iTBS. The increased white matter integrity near the stimulation sites may reflect improvements in cortical function mediated by excitatory rTMS through its ability to facilitate synaptic connections.

Allendorfer, Jane B.; Storrs, Judd M.; Szaflarski, Jerzy P.

2012-01-01

293

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

294

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

PubMed Central

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 (T1/T2/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 (Pcorrected?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.

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

2011-01-01

295

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

296

Can magnetoencephalography track the afferent information flow along white matter thalamo-cortical fibers?  

PubMed

White matter thalamo-cortical fibers allow the communication of distant brain regions by carrying neuronal signals. Mapping non-invasively the information flow within white matter fibers is regarded so far as impossible. We investigated here whether information flow propagating along thalamo-cortical fibers can be detected using magnetoencephalography (MEG). Somatosensory evoked fields (SEFs) were recorded from healthy subjects and a patient with a unilateral, prenatally acquired, white matter lesion, which had induced the development of an abnormal trajectory of thalamo-cortical fibers. Equivalent current dipole (ECD) was used to model sources of SEFs. ECD at ~15 ms after stimulus onset was located within or close to the contralateral thalamus at the proximity of a hemodynamic response detected during a similar fMRI experiment. At the M20 peak latency, ECD was localized within the hand area of the contralateral primary somatosensory cortex (Brodmann area 3b (BA3b)). In healthy subjects, ECD changed dynamically position from thalamus to BA3b following a curved path, which was partially overlapping the thalamo-cortical fibers reconstructed by tractography. In the patient, ECD followed a similar path only in the intact hemisphere. In the affected hemisphere, the dipole trajectory circumnavigated the extended lesion on its way to the preserved primary somatosensory cortex--similar to the trajectory findings. Evidence from different methodological approaches converges on the conclusion that MEG can track the afferent information flow along thalamo-cortical fibers and in contrast to the traditional view can localize under presuppositions deep thalamic sources. PMID:22266410

Papadelis, Christos; Leonardelli, Elisa; Staudt, Martin; Braun, Christoph

2012-04-01

297

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

298

White matter hyperintensities in subjects with bipolar disorder.  

PubMed

There have been divergent reports on the prevalence and severity of white matter hyperintensities (WMH) on brain magnetic resonance (MR) images in subjects with bipolar disorder. In the present study, evaluations were made on the prevalence and severity of WMH in subjects with bipolar disorder using contiguous 3-mm thick MR slices as well as fluid attenuated inversion recovery (FLAIR) images. A detailed WMH rating system was employed to assess these WMH. A total of 43 bipolar patients, as diagnosed by the Structured Clinical Interview from the Diagnostic and Statistical Manual-IV (SCID-IV), and 39 healthy comparison subjects were scanned using a 1.5-T whole body GE magnetic resonance scanner. WMH were assessed with a modified composite version of the Fazekas' and Coffey's rating scales to detect less severe WMH. Periventricular and subcortical WMH were coded separately. Subjects with bipolar disorder had greater prevalence of WMH abnormalities than comparison subjects (Bipolar, grade 1 = 11.6%, grade 2 = 9.3%, grade 3 = 7.0%; Comparison, grade 1 = 5.1%, grade 2 = 2.6%, grade 3 = 0%). This difference is mainly due to the differences in deep WMH (Bipolar, grade 1 = 14.0%, grade 2 = 14.0%; Comparison, grade 1 = 7.7%, grade 2 = 0%). The current study confirms the higher prevalence of WMH in subjects with bipolar disorder. Differences of small-sized WMH abnormalities between groups were successfully detected using a large number of bipolar subjects and thinner sliced MR images with FLAIR. PMID:15482583

Ahn, Kyung Heup; Lyoo, In Kyoon; Lee, Ho Kyu; Song, In Chan; Oh, Jung Su; Hwang, Jaeuk; Kwon, Juyong; Kim, Minue J; Kim, Minjeong; Renshaw, Perry F

2004-10-01

299

The role of pre-treatment white matter abnormalities in developing white matter changes following whole brain radiation: a volumetric study.  

PubMed

White matter injury is a known complication of whole brain radiation (WBRT). Little is known about the factors that predispose a patient to such injury. The current study used MR volumetrics to examine risk factors, in particular the influence of pre-treatment white matter health, in developing white matter change (WMC) following WBRT. Thirty-four patients with unilateral metastatic disease underwent FLAIR MRI pre-treatment and at several time points following treatment. The volume of abnormal FLAIR signal in the white matter was measured in the hemisphere contralateral to the diseased hemisphere at each time point. Analyses were restricted to the uninvolved hemisphere to allow for the measurement of WBRT effects without the potential confounding effects of the disease on imaging findings. The relationship between select pre-treatment clinical variables and the degree of WMC following treatment was examined using correlational and regression based analyses. Age when treated and volume of abnormal FLAIR prior to treatment were significantly associated with WMC following WBRT; however, pre-treatment FLAIR volume was the strongest predictor of post-treatment WMCs. Age did not add any predictive value once white matter status was considered. No significant relationships were found between biological equivalent dose and select cerebrovascular risk factors (total glucose, blood pressure, BMI) and development of WMCs. The findings from this study identify pre-treatment white matter health as an important risk factor in developing WMC following WBRT. This information can be used to make more informed decisions and counsel patients on their risk for treatment effects. PMID:23813291

Sabsevitz, David S; Bovi, Joseph A; Leo, Peter D; Laviolette, Peter S; Rand, Scott D; Mueller, Wade M; Schultz, Christopher J

2013-09-01

300

Neurodevelopmental and neurodegenerative models of schizophrenia: white matter at the center stage.  

PubMed

Schizophrenia is a disorder of cerebral disconnectivity whose lifetime course is modeled as both neurodevelopmental and neurodegenerative. The neurodevelopmental models attribute schizophrenia to alterations in the prenatal-to-early adolescent development. The neurodegenerative models identify progressive neurodegeneration as its core attribute. Historically, the physiology, pharmacology, and treatment targets in schizophrenia were conceptualized in terms of neurons, neurotransmitter levels, and synaptic receptors. Much of the evidence for both models was derived from studies of cortical and subcortical gray matter. We argue that the dynamics of the lifetime trajectory of white matter, and the consistency of connectivity deficits in schizophrenia, support white matter integrity as a promising phenotype to evaluate the competing evidence for and against neurodevelopmental and neurodegenerative heuristics. We develop this perspective by reviewing normal lifetime trajectories of white and gray matter changes. We highlighted the overlap between the age of peak of white matter development and the age of onset of schizophrenia and reviewed findings of white matter abnormalities prior to, at the onset, and at chronic stages of schizophrenia. We emphasized the findings of reduced white matter integrity at the onset and findings of accelerated decline in chronic stages, but the developmental trajectory that precedes the onset is largely unknown. We propose 4 probable lifetime white matter trajectory models that can be used as the basis for separation between the neurodevelopmental and neurodegenerative etiologies. We argue that a combination of the cross-sectional and longitudinal studies of white matter integrity in patients may be used to bridge the neurodevelopment and degeneration heuristics to advance schizophrenia research. PMID:24870447

Kochunov, Peter; Hong, L Elliot

2014-07-01

301

Oligodendrocytes within astrocytes ("emperipolesis") in the white matter in Creutzfeldt-Jakob disease.  

PubMed

The occurrence of oligodendrocytes within astrocytes ("emperipolesis") has been described in demyelinating lesions in cases of multiple sclerosis and also in other non-demyelinating disorders. We found that this finding was common in the cerebral white matter of patients with Creutzfeldt-Jakob disease (CJD). Eight consecutive autopsy cases of sporadic CJD were reviewed, and in every case the gray matter exhibited classical histopathological features of CJD. In five cases with a long clinical course, the cerebral white matter was severely involved, and both axons and myelin sheaths were lost markedly. Within this devastated white matter, many hypertrophic astrocytes were found to engulf one to several oligodendrocytes within their cytoplasm (emperipolesis). The oligodendroglial nature of the engulfed cells was corroborated by nuclear immunoreactivity for anti-human Olig 2 antibody. In the remaining three cases, whose clinical course was short, the cerebral white matter was relatively well preserved, and emperipolesis was not or only very rarely found. The prevalence of emperipolesis of this type in the white matter in CJD was well correlated with the severity of the white matter lesions. PMID:15235800

Shintaku, Masayuki; Yutani, Chikao

2004-09-01

302

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

303

Diffusely abnormal white matter in multiple sclerosis: further histologic studies provide evidence for a primary lipid abnormality with neurodegeneration.  

PubMed

Although multiple sclerosis (MS) lesions have been studied extensively using histology and magnetic resonance imaging (MRI), little is known about diffusely abnormal white matter (DAWM). Diffusely abnormal white matter, regions with reduced mild MRI hyperintensity and ill-defined boundaries, show reduced myelin water fraction, and decreased Luxol fast blue staining of myelin phospholipids, with relative preservation of myelin basic protein and 2',3'-cyclic-nucleotide 3'-phosphohydrolase. Because DAWM may be important in MS disability and progression, further histologic characterization is warranted. The MRI data were collected on 14 formalin-fixed MS brain samples that were then stained for myelin phospholipids, myelin proteins, astrocytes and axons. Diffusely abnormal white matter showed reduced myelin water fraction (-30%, p < 0.05 for 13 samples). Myelin phospholipids showed the most dramatic and consistent histologic reductions in staining optical density (-29% Luxol fast blue and -24% Weil's, p < 0.05 for 13 and 14 samples,respectively) with lesser myelin protein involvement (-11% myelin-associated glycoprotein, -10% myelin basic protein, -8% myelin-oligodendrocyte glycoprotein, -7% proteolipid protein, -5% 2',3'-cyclic-nucleotide 3'-phosphohydrolase, p < 0.05 for 3, 3, 1, 2, and 3 samples, respectively). Axonal involvement was intermediate. Diffusely abnormal white matter lipid and protein reductions occurred independently. These findings suggest a primary lipid abnormality in DAWM that exceeds protein loss and is accompanied by axonal degeneration. These phenomena may be important in MS pathogenesis and disease progression, which is prominent in individuals with DAWM. PMID:23242281

Laule, Cornelia; Pavlova, Vlady; Leung, Esther; Zhao, Guojun; MacKay, Alex L; Kozlowski, Piotr; Traboulsee, Anthony L; Li, David K B; Moore, G R Wayne

2013-01-01

304

White matter hyperintensities are associated with visual search behavior independent of generalized slowing in aging.  

PubMed

A fundamental controversy is whether cognitive decline with advancing age can be entirely explained by decreased processing speed, or whether specific neural changes can elicit cognitive decline, independent of slowing. These hypotheses are anchored by studies of healthy older individuals where age is presumed the sole influence. Unfortunately, advancing age is also associated with asymptomatic brain white matter injury. We hypothesized that differences in white matter injury extent, manifest by MRI white matter hyperintensities (WMH), mediate differences in visual attentional control in healthy aging, beyond processing speed differences. We tested young and cognitively healthy older adults on search tasks indexing speed and attentional control. Increasing age was associated with generally slowed performance. WMH were also associated with slowed search times independent of processing speed differences. Consistent with evidence attributing reduced network connectivity to WMH, these results conclusively demonstrate that clinically silent white matter injury contributes to slower search performance indicative of compromised cognitive control, independent of generalized slowing of processing speed. PMID:24183716

Lockhart, Samuel N; Roach, Alexandra E; Luck, Steven J; Geng, Joy; Beckett, Laurel; Carmichael, Owen; DeCarli, Charles

2014-01-01

305

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

306

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

307

Quantitative and visual analysis of white matter integrity using diffusion tensor imaging  

NASA Astrophysics Data System (ADS)

A new fiber tract-oriented quantitative and visual analysis scheme using diffusion tensor imaging (DTI) is developed to study the regional micro structural white matter changes along major fiber bundles which may not be effectively revealed by existing methods due to the curved spatial nature of neuronal paths. Our technique is based on DTI tractography and geodesic path mapping, which establishes correspondences to allow cross-subject evaluation of diffusion properties by parameterizing the fiber pathways as a function of geodesic distance. A novel isonodes visualization scheme is proposed to render regional statistical features along the fiber pathways. Assessment of the technique reveals specific anatomical locations along the genu of the corpus callosum paths with significant diffusion property changes in the amnestic mild cognitive impairment subjects. The experimental results show that this approach is promising and may provide a sensitive technique to study the integrity of neuronal connectivity in human brain.

Liang, Xuwei; Zhuang, Qi; Cao, Ning; Zhang, Jun

2009-02-01

308

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

309

Atlas-based whole brain white matter analysis using large deformation diffeomorphic metric mapping: application to normal elderly and Alzheimer's disease participants.  

PubMed

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. PMID:19385016

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

2009-06-01

310

Adolescent Engagement in Dangerous Behaviors Is Associated with Increased White Matter Maturity of Frontal Cortex  

Microsoft Academic Search

BackgroundMyelination of white matter in the brain continues throughout adolescence and early adulthood. This cortical immaturity has been suggested as a potential cause of dangerous and impulsive behaviors in adolescence.Methodology\\/Principal FindingsWe tested this hypothesis in a group of healthy adolescents, age 12–18 (N = 91), who underwent diffusion tensor imaging (DTI) to delineate cortical white matter tracts. As a measure

Gregory S. Berns; Sara Moore; C. Monica Capra; Antonio Verdejo García

2009-01-01

311

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

312

Maturation-Dependent Vulnerability of Perinatal White Matter in Premature Birth  

Microsoft Academic Search

Abstract—Survivors of premature birth have a predilection for perinatal brain injury, especially to 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 cystic necrotic lesions (periventricular leukomalacia) and diffuse myelination disturbances. Recent neuroimaging,studies support that

Stephen A. Back; Melissa M. McClure

2010-01-01

313

Automated measurement of brain and white matter lesion volume in type 2 diabetes mellitus  

Microsoft Academic Search

Aims\\/hypothesis  Type 2 diabetes mellitus has been associated with brain atrophy and cognitive decline, but the association with ischaemic\\u000a white matter lesions is unclear. Previous neuroimaging studies have mainly used semiquantitative rating scales to measure\\u000a atrophy and white matter lesions (WMLs). In this study we used an automated segmentation technique to investigate the association\\u000a of type 2 diabetes, several diabetes-related risk

C. Jongen; J. van der Grond; L. J. Kappelle; G. J. Biessels; M. A. Viergever; J. P. W. Pluim

2007-01-01

314

Mapping of ApoE4 related white matter damage using diffusion MRI  

NASA Astrophysics Data System (ADS)

ApoliopoproteinE ?4 (ApoE-?4) polymorphism is the most well known genetic risk factor for developing Alzheimers Disease. The exact mechanism through which ApoE 4 increases AD risk is not fully known, but may be related to decreased clearance and increased oligomerization of A?. By making measurements of white matter integrity via diffusion MR and correlating the metrics in a voxel-based statistical analysis with ApoE-?4 genotype (whilst controlling for vascular risk factor, gender, cognitive status and age) we are able to identify changes in white matter associated with carrying an ApoE ?4 allele. We found potentially significant regions (Puncorrected < 0:05) near the hippocampus and the posterior cingulum that were independent of voxels that correlated with age or clinical dementia rating (CDR) status suggesting that ApoE may affect cognitive decline via a pathway in dependent of normal aging and acute insults that can be measured by CDR and Framingham Coronary Risk Score (FCRS).

Tsao, Sinchai; Gajawelli, Niharika; Hwang, Darryl H.; Kriger, Stephen; Law, Meng; Chui, Helena; Weiner, Michael; Lepore, Natasha

2014-04-01

315

Microembolism Induces Anhedonia but No Detectable Changes in White Matter Integrity in Aged Rats  

PubMed Central

Microvascular disease leads to alterations of cerebral vasculature including the formation of microembolic (ME) strokes. Though ME are associated with changes in mood and the severity and progression of cognitive decline, the effect of ME strokes on cerebral microstructure and its relationship to behavioral endpoints is unknown. Here, we used adult and aged male rats to test the hypotheses that ME lesions result in subtle changes to white and gray matter integrity as detected by high-throughput diffusion tensor imaging (DTI) and that these structural disruptions correspond to behavioral deficits. Two weeks post-surgery, aged animals showed depressive-like behaviors in the sucrose consumption test in the absence of altered cerebral diffusivity as assessed by ex-vivo DTI. Furthermore, DTI indices did not correlate with the degree of behavioral disruption in aged animals or in a subset of animals with observed tissue cavitation and subtle DTI alterations. Together, data suggest that behavioral deficits are not the result of damage to brain regions or white matter tracts, rather the activity of other systems may underlie functional disruption and recovery.

Nemeth, Christina L.; Gutman, David A.; Majeed, Waqas; Keilholz, Shella D.; Neigh, Gretchen N.

2014-01-01

316

Automated Fiber Tracking of Human Brain White Matter Using Diffusion Tensor Imaging  

PubMed Central

Reconstruction of white matter tracts based on diffusion tensor imaging (DTI) is currently widely used in clinical research. This reconstruction allows us to identify coordinates of specific white matter tracts and to investigate their anatomy. Fiber reconstruction, however, relies on manual identification of anatomical landmarks of a tract of interest, which is based on subjective judgment and thus a potential source of experimental variability. Here, an automated tract reconstruction approach is introduced. A set of reference regions of interest (rROIs) known to select a tract of interest was marked in our DTI brain atlas. The atlas was then linearly transformed to each subject, and the rROI set was transferred to the subject for tract reconstruction. Agreement between the automated and manual approaches was measured for 11 tracts in 10 healthy volunteers and found to be excellent (kappa > 0.8) and remained high up to 4–5 mm of the linear transformation errors. As a first example, the automated approach was applied to brain tumor patients and strategies to cope with severe anatomical abnormalities are discussed.

Zhang, Weihong; Olivi, Alessandro; Hertig, Samuel J.; van Zijl, Peter; Mori, Susumu

2008-01-01

317

Novel homozygous DEAF1 variant suspected in causing white matter disease, intellectual disability, and microcephaly.  

PubMed

DEAF1 encodes a transcriptional binding factor and is a regulator of serotonin receptor 1A. Its protein has a significant expression in the neurons of different brain regions and is involved in early embryonic development. In addition, its role in neural tube development is evident from the knockout mouse as many homozygotes have exencephaly. Heterozygous mutations of this gene have been linked to intellectual disability in addition to the gene's involvement in major depression, suicidal tendencies, and panic disorder. In this clinical report, we describe two children from a consanguineous family with intellectual disability, microcephaly, and hypotonia. The brain MRI of both patients showed bilateral and symmetrical white matter abnormalities, and one of the patients had a seizure disorder. Using whole exome sequencing combined with homozygosity mapping, a homozygous p.R226W (c.676C>T) mutation in DEAF1 was found in both patients. Furthermore, sequencing analysis confirmed complete segregation in tested family members and absence of the mutation in control cohort (n = 650). The mutation is located in a highly conserved structural domain that mediates DNA binding and therefore regulates transcriptional activity of its target molecules. This study indicates, for the first time to our knowledge, a hereditary role of DEAF1 in white matter abnormalities, microcephaly and syndromic intellectual disability. PMID:24668509

Faqeih, Eissa A; Al-Owain, Mohammed; Colak, Dilek; Kenana, Rosan; Al-Yafee, Yusra; Al-Dosary, Mazhor; Al-Saman, Abdulaziz; Albalawi, Fadwa; Al-Sarar, Dalia; Domiaty, Dalia; Daghestani, Maha; Kaya, Namik

2014-06-01

318

Atlas-guided tract reconstruction for automated and comprehensive examination of the white matter anatomy.  

PubMed

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. PMID:20570617

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

2010-10-01

319

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

320

Microembolism induces anhedonia but no detectable changes in white matter integrity in aged rats.  

PubMed

Microvascular disease leads to alterations of cerebral vasculature including the formation of microembolic (ME) strokes. Though ME are associated with changes in mood and the severity and progression of cognitive decline, the effect of ME strokes on cerebral microstructure and its relationship to behavioral endpoints is unknown. Here, we used adult and aged male rats to test the hypotheses that ME lesions result in subtle changes to white and gray matter integrity as detected by high-throughput diffusion tensor imaging (DTI) and that these structural disruptions correspond to behavioral deficits. Two weeks post-surgery, aged animals showed depressive-like behaviors in the sucrose consumption test in the absence of altered cerebral diffusivity as assessed by ex-vivo DTI. Furthermore, DTI indices did not correlate with the degree of behavioral disruption in aged animals or in a subset of animals with observed tissue cavitation and subtle DTI alterations. Together, data suggest that behavioral deficits are not the result of damage to brain regions or white matter tracts, rather the activity of other systems may underlie functional disruption and recovery. PMID:24811070

Nemeth, Christina L; Gutman, David A; Majeed, Waqas; Keilholz, Shella D; Neigh, Gretchen N

2014-01-01

321

Expert cognitive control and individual differences associated with frontal and parietal white matter microstructure  

PubMed Central

Although many functional imaging studies have reported frontal activity associated with ‘cognitive control’ tasks, little is understood about factors underlying individual differences in performance. Here we compared the behaviour and brain structure of healthy controls with fighter pilots, an expert group trained to make precision choices at speed in the presence of conflicting cues. Two different behavioural paradigms – Eriksen Flanker and Change of plan tasks – were used to assess the influence of distractors and the ability to update ongoing action plans. Fighter pilots demonstrated superior cognitive control as indexed by accuracy and post-conflict adaptation on the flanker task, but also showed increased sensitivity to irrelevant, distracting choices. By contrast, when pilots were examined on their ability to inhibit a current action plan in favour of an alternative response, their performance was no better than the control group. Diffusion weighted imaging revealed differences in white matter radial diffusivity between pilots and controls not only in the right dorsomedial frontal region but also in the right parietal lobe. Moreover, analysis of individual differences in reaction time costs for conflict trials on the flanker task demonstrated significant correlations with radial diffusivity at these locations, but in different directions. Post-conflict adaptation effects, however, were confined to the dorsomedial frontal locus. The findings demonstrate that in humans expert cognitive control may surprisingly be mediated by enhanced response gain to both relevant and irrelevant stimuli, and is accompanied by structural alterations in the white matter of the frontal and parietal lobe.

Roberts, R.E.; Anderson, E. J.; Husain, M.

2011-01-01

322

Mapping of ApoE4 Related White Matter Damage using Diffusion MRI  

PubMed Central

ApoliopoproteinE ?4 (ApoE-?4) polymorphism is the most well known genetic risk factor for developing Alzheimers Disease. The exact mechanism through which ApoE ?4 increases AD risk is not fully known, but may be related to decreased clearance and increased oligomerization of A?. By making measurements of white matter integrity via diffusion MR and correlating the metrics in a voxel-based statistical analysis with ApoE-?4 genotype (whilst controlling for vascular risk factor, gender, cognitive status and age) we are able to identify changes in white matter associated with carrying an ApoE ?4 allele. We found potentially significant regions (Puncorrected < 0.05) near the hippocampus and the posterior cingulum that were independent of voxels that correlated with age or clinical dementia rating (CDR) status suggesting that ApoE may affect cognitive decline via a pathway in dependent of normal aging and acute insults that can be measured by CDR and Framingham Coronary Risk Score (FCRS).

Tsao, Sinchai; Gajawelli, Niharika; Hwang, Darryl Hwa; Kriger, Stephen; Law, Meng; Chui, Helena; Weiner, Michael; Lepore, Natasha

2014-01-01

323

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

324

Nociceptin/orphanin FQ exacerbates excitotoxic white-matter lesions in the murine neonatal brain  

PubMed Central

Intracerebral administration of the excitotoxin ibotenate to newborn mice induces white-matter lesions, mimicking brain lesions that occur in human preterm infants. Nociceptin (NC), also called orphanin FQ, is the endogenous ligand of the opioid receptor-like 1 (ORL1) receptor and does not bind classical high-affinity opioid receptors. In the present study, administration of NC exacerbated ibotenate-induced white-matter lesions while coadministration of ibotenate with either of two NC antagonists reduced excitotoxic white-matter lesions by up to 64%. Neither ibotenate plus endomorphin I (a selective ? receptor agonist), nor ibotenate plus naloxone (a classical opioid receptor antagonist) modulated the excitotoxic lesion. Pretreatment with antisense oligonucleotides targeting the NC precursor peptide mRNA significantly reduced ibotenate-induced white-matter damage. Finally, high doses of fentanyl, which stimulates both classical ? opioid receptors and ORL1, exacerbated excitotoxic white-matter lesion. This toxic effect was blocked by inhibiting ORL1 but not classical opioid receptors. Together, these findings show that endogenous or exogenous stimulation of the ORL1 receptor can be neurotoxic and that blocking NC signaling protects the white matter against excitotoxic challenge. These data point to potential new avenues for neuroprotection in human preterm infants at high risk of brain lesions.

Laudenbach, Vincent; Calo, Girolamo; Guerrini, Remo; Lamboley, Geraldine; Benoist, Jean-Francois; Evrard, Philippe; Gressens, Pierre

2001-01-01

325

Altered white matter integrity in the congenital and late blind people.  

PubMed

The blind subjects have experienced a series of brain structural and functional alterations due to the visual deprivation. It remains unclear as to whether white matter changes differ between blind subjects with visual deprivation before and after a critical developmental period. The present study offered a direct comparison in changes of white matter fractional anisotropy (FA) between congenital blind (CB) and late blind (LB) individuals. Twenty CB, 21 LB (blindness onset after 18 years old), and 40 sight control (SC) subjects were recruited. Both the tract-based spatial statistics (TBSS) and voxel-based analysis (VBA) showed lower FA in the bilateral optic radiations in both blind groups, suggesting that the loss of white matter integrity was the prominent hallmark in the blind people. The LB group showed more extensive white matter impairment than the CB group, indicating the mechanisms of white matter FA changes are different between the CB and LB groups. Using a loose threshold, a trend of an increased FA was found in the bilateral corticospinal tracts in the LB but with a smaller spatial extent relative to the CB. These results suggest that white matter FA changes in the blind subjects are the reflection of multiple mechanisms, including the axonal degeneration, deafferentation, and plasticity. PMID:23710371

Wang, Dawei; Qin, Wen; Liu, Yong; Zhang, Yunting; Jiang, Tianzi; Yu, Chunshui

2013-01-01

326

Altered White Matter Integrity in the Congenital and Late Blind People  

PubMed Central

The blind subjects have experienced a series of brain structural and functional alterations due to the visual deprivation. It remains unclear as to whether white matter changes differ between blind subjects with visual deprivation before and after a critical developmental period. The present study offered a direct comparison in changes of white matter fractional anisotropy (FA) between congenital blind (CB) and late blind (LB) individuals. Twenty CB, 21 LB (blindness onset after 18 years old), and 40 sight control (SC) subjects were recruited. Both the tract-based spatial statistics (TBSS) and voxel-based analysis (VBA) showed lower FA in the bilateral optic radiations in both blind groups, suggesting that the loss of white matter integrity was the prominent hallmark in the blind people. The LB group showed more extensive white matter impairment than the CB group, indicating the mechanisms of white matter FA changes are different between the CB and LB groups. Using a loose threshold, a trend of an increased FA was found in the bilateral corticospinal tracts in the LB but with a smaller spatial extent relative to the CB. These results suggest that white matter FA changes in the blind subjects are the reflection of multiple mechanisms, including the axonal degeneration, deafferentation, and plasticity.

Wang, Dawei; Qin, Wen; Liu, Yong; Zhang, Yunting; Jiang, Tianzi; Yu, Chunshui

2013-01-01

327

Vestibular Loss and Balance Training Cause Similar Changes in Human Cerebral White Matter Fractional Anisotropy  

PubMed Central

Patients with bilateral vestibular loss suffer from severe balance deficits during normal everyday movements. Ballet dancers, figure skaters, or slackliners, in contrast, are extraordinarily well trained in maintaining balance for the extreme balance situations that they are exposed to. Both training and disease can lead to changes in the diffusion properties of white matter that are related to skill level or disease progression respectively. In this study, we used diffusion tensor imaging (DTI) to compare white matter diffusivity between these two study groups and their age- and sex-matched controls. We found that vestibular patients and balance-trained subjects show a reduction of fractional anisotropy in similar white matter tracts, due to a relative increase in radial diffusivity (perpendicular to the main diffusion direction). Reduced fractional anisotropy was not only found in sensory and motor areas, but in a widespread network including long-range connections, limbic and association pathways. The reduced fractional anisotropy did not correlate with any cognitive, disease-related or skill-related factors. The similarity in FA between the two study groups, together with the absence of a relationship between skill or disease factors and white matter changes, suggests a common mechanism for these white matter differences. We propose that both study groups must exert increased effort to meet their respective usual balance requirements. Since balance training has been shown to effectively reduce the symptoms of vestibular failure, the changes in white matter shown here may represent a neuronal mechanism for rehabilitation.

Hummel, Nadine; Hufner, Katharina; Stephan, Thomas; Linn, Jennifer; Kremmyda, Olympia; Brandt, Thomas; Flanagin, Virginia L.

2014-01-01

328

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

329

Vestibular loss and balance training cause similar changes in human cerebral white matter fractional anisotropy.  

PubMed

Patients with bilateral vestibular loss suffer from severe balance deficits during normal everyday movements. Ballet dancers, figure skaters, or slackliners, in contrast, are extraordinarily well trained in maintaining balance for the extreme balance situations that they are exposed to. Both training and disease can lead to changes in the diffusion properties of white matter that are related to skill level or disease progression respectively. In this study, we used diffusion tensor imaging (DTI) to compare white matter diffusivity between these two study groups and their age- and sex-matched controls. We found that vestibular patients and balance-trained subjects show a reduction of fractional anisotropy in similar white matter tracts, due to a relative increase in radial diffusivity (perpendicular to the main diffusion direction). Reduced fractional anisotropy was not only found in sensory and motor areas, but in a widespread network including long-range connections, limbic and association pathways. The reduced fractional anisotropy did not correlate with any cognitive, disease-related or skill-related factors. The similarity in FA between the two study groups, together with the absence of a relationship between skill or disease factors and white matter changes, suggests a common mechanism for these white matter differences. We propose that both study groups must exert increased effort to meet their respective usual balance requirements. Since balance training has been shown to effectively reduce the symptoms of vestibular failure, the changes in white matter shown here may represent a neuronal mechanism for rehabilitation. PMID:24776524

Hummel, Nadine; Hüfner, Katharina; Stephan, Thomas; Linn, Jennifer; Kremmyda, Olympia; Brandt, Thomas; Flanagin, Virginia L

2014-01-01

330

Mapping joint grey and white matter reductions in Alzheimer's disease using joint independent component analysis  

PubMed Central

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.

Guo, Xiaojuan; Han, Yuan; Chen, Kewei; Wang, Yan; Yao, Li

2013-01-01

331

Oligodendrocyte precursors induce early blood-brain barrier opening after white matter injury.  

PubMed

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. PMID:23281396

Seo, Ji Hae; Miyamoto, Nobukazu; Hayakawa, Kazuhide; Pham, Loc-Duyen D; Maki, Takakuni; Ayata, Cenk; Kim, Kyu-Won; Lo, Eng H; Arai, Ken

2013-02-01

332

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

333

Reconstruction of White Matter Tracts via Repeated Deterministic Streamline Tracking - Initial Experience  

PubMed Central

Diffusion Tensor Imaging (DTI) and fiber tractography are established methods to reconstruct major white matter tracts in the human brain in-vivo. Particularly in the context of neurosurgical procedures, reliable information about the course of fiber bundles is important to minimize postoperative deficits while maximizing the tumor resection volume. Since routinely used deterministic streamline tractography approaches often underestimate the spatial extent of white matter tracts, a novel approach to improve fiber segmentation is presented here, considering clinical time constraints. Therefore, fiber tracking visualization is enhanced with statistical information from multiple tracking applications to determine uncertainty in reconstruction based on clinical DTI data. After initial deterministic fiber tracking and centerline calculation, new seed regions are generated along the result’s midline. Tracking is applied to all new seed regions afterwards, varying in number and applied offset. The number of fibers passing each voxel is computed to model different levels of fiber bundle membership. Experimental results using an artificial data set of an anatomical software phantom are presented, using the Dice Similarity Coefficient (DSC) as a measure of segmentation quality. Different parameter combinations were classified to be superior to others providing significantly improved results with DSCs of 81.02%±4.12%, 81.32%±4.22% and 80.99%±3.81% for different levels of added noise in comparison to the deterministic fiber tracking procedure using the two-ROI approach with average DSCs of 65.08%±5.31%, 64.73%±6.02% and 65.91%±6.42%. Whole brain tractography based on the seed volume generated by the calculated seeds delivers average DSCs of 67.12%±0.86%, 75.10%±0.28% and 72.91%±0.15%, original whole brain tractography delivers DSCs of 67.16%, 75.03% and 75.54%, using initial ROIs as combined include regions, which is clearly improved by the repeated fiber tractography method.

Bauer, Miriam H. A.; Kuhnt, Daniela; Barbieri, Sebastiano; Klein, Jan; Becker, Andreas; Freisleben, Bernd; Hahn, Horst K.; Nimsky, Christopher

2013-01-01

334

Community Influences on White Racial Attitudes: What Matters and Why?  

PubMed Central

Tracing the roots of racial attitudes in historical events and individual biographies has been a longstanding goal of race relations scholars. Recent years have seen a new development in racial attitude research: Local community context has entered the spotlight as a potential influence on racial views. The race composition of the locality has been the most common focus; evidence from earlier decades suggests that white Americans are more likely to hold anti-black attitudes if they live in areas where the African American population is relatively large. However, an influential 2000 article argued that the socioeconomic composition of the white community is a more powerful influence on white attitudes: In low-SES locales, “stress-inducing” deprivations and hardships in whites’ own lives purportedly lead them to disparage blacks. The study reported here re-assesses this “scapegoating” claim, using data from the 1998–2002 General Social Surveys linked to 2000 census information about communities. Across many dimensions of racial attitudes, there is pronounced influence of both local racial proportions and college completion rates among white residents. However, the economic dimension of SES exerts negligible influence on white racial attitudes, suggesting that local processes other than scapegoating must be at work.

Taylor, Marylee C.; Mateyka, Peter J.

2014-01-01

335

Combining Fiber Dissection, Plastination, and Tractography for Neuroanatomical Education: Revealing the Cerebellar Nuclei and Their White Matter Connections  

ERIC Educational Resources Information Center

In recent years, there has been a growing interest in white matter anatomy of the human brain. With advances in brain imaging techniques, the significance of white matter integrity for brain function has been demonstrated in various neurological and psychiatric disorders. As the demand for interpretation of clinical and imaging data on white

Arnts, Hisse; Kleinnijenhuis, Michiel; Kooloos, Jan G. M.; Schepens-Franke, Annelieke N.; van Cappellen van Walsum, Anne-Marie

2014-01-01

336

Grey and white matter abnormalities in temporal lobe epilepsy with and without mesial temporal sclerosis  

PubMed Central

Temporal lobe epilepsy with (TLE-mts) and without (TLE-no) mesial temporal sclerosis display different patterns of cortical neuronal loss, suggesting that the distribution of white matter damage may also differ between the sub-groups. The purpose of this study was to examine patterns of white matter damage in TLE-mts and TLE-no and to determine if identified changes are related to neuronal loss at the presumed seizure focus. The 4 T diffusion tensor imaging (DTI) and T1-weighted data were acquired for 22 TLE-mts, 21 TLE-no and 31 healthy controls. Tract-based spatial statistics (TBSS) was used to compare fractional anisotropy (FA) maps and voxel-based morphometry (VBM) was used to identify grey matter (GM) volume atrophy. Correlation analysis was conducted between the FA maps and neuronal loss at the presumed seizure focus. In TLE-mts, reduced FA was identified in the genu, body and splenium of the corpus callosum, bilateral corona radiata, cingulum, external capsule, ipsilateral internal capsule and uncinate fasciculus. In TLE-no, FA decreases were identified in the genu, the body of the corpus callosum and ipsilateral anterior corona radiata. The FA positively correlated with ipsilateral hippocampal volume. Widespread extra-focal GM atrophy was associated with both sub-groups. Despite widespread and extensive GM atrophy displaying different anatomical patterns in both sub-groups, TLE-mts demonstrated more extensive FA abnormalities than TLE-no. The microstructural organization in the corpus callosum was related to hippocampal volume in both patients and healthy subjects demonstrating the association of these distal regions.

Scanlon, Cathy; Mueller, Susanne G.; Cheong, Ian; Hartig, Miriam; Weiner, Michael W.

2013-01-01

337

Increased white matter connectivity in euthymic bipolar patients: diffusion tensor tractography between the subgenual cingulate and the amygdalo-hippocampal complex  

Microsoft Academic Search

Bipolar disorder has been associated with anatomical as well as functional abnormalities in a brain network that mediates normal and impaired emotion regulation. Previous brain imaging studies have highlighted the subgenual cingulate (SC) and the amygdalo-hippocampal (AH) complex as core regions of this network. Thus we investigated white matter (WM) fiber tracts between the SC and the AH region, the

J Houenou; M Wessa; G Douaud; M Leboyer; S Chanraud; M Perrin; C Poupon; J-L Martinot; M-L Paillere-Martinot

2007-01-01

338

White matter damage disorganizes brain functional networks in amnestic mild cognitive impairment.  

PubMed

Abstract Although progressive functional brain network disruption has been one of the hallmarks of Alzheimer's Disease, little is known about the origin of this functional impairment that underlies cognitive symptoms. We investigated how the loss of white matter (WM) integrity disrupts the organization of the functional networks at different frequency bands. The analyses were performed in a sample of healthy elders and mild cognitive impairment (MCI) subjects. Spontaneous brain magnetic activity (measured with magnetoencephalography) was characterized with phase synchronization analysis, and graph theory was applied to the functional networks. We identified WM areas (using diffusion weighted magnetic resonance imaging) that showed a statistical dependence between the fractional anisotropy and the graph metrics. These regions are part of an episodic memory network and were also related to cognitive functions. Our data support the hypothesis that disruption of the anatomical networks influences the organization at the functional level resulting in the prodromal dementia syndrome of MCI. PMID:24617580

Pineda-Pardo, José Angel; Garcés, Pilar; López, María Eugenia; Aurtenetxe, Sara; Cuesta, Pablo; Marcos, Alberto; Montejo, Pedro; Yus, Miguel; Hernández-Tamames, Juan Antonio; Del Pozo, Francisco; Becker, James T; Maestú, Fernando

2014-06-01

339

Effects of the BDNF Val66Met Polymorphism on White Matter Microstructure in Healthy Adults  

PubMed Central

The BDNF Val66Met polymorphism, a possible risk variant for mental disorders, is a potent modulator of neural plasticity in humans and has been linked to deficits in gray matter structure, function, and cognition. The impact of the variant on brain white matter structure, however, is controversial and remains poorly understood. Here, we used diffusion tensor imaging to examine the effects of BDNF Val66Met genotype on white matter microstructure in a sample of 85 healthy Caucasian adults. We demonstrate decreases of fractional anisotropy and widespread increases in radial diffusivity in Val/Val homozygotes compared with Met-allele carriers, particularly in prefrontal and occipital pathways. These data provide an independent confirmation of prior imaging genetics work, are consistent with complex effects of the BDNF Val66Met polymorphism on human brain structure, and may serve to generate hypotheses about variation in white matter microstructure in mental disorders associated with this variant.

Tost, Heike; Alam, Tajvar; Geramita, Matthew; Rebsch, Christine; Kolachana, Bhaskar; Dickinson, Dwight; Verchinski, Beth A; Lemaitre, Herve; Barnett, Alan S; Trampush, Joey W; Weinberger, Daniel R; Marenco, Stefano

2013-01-01

340

Specific relations between neurodevelopmental abilities and white matter microstructure in children born preterm.  

PubMed

Survivors of preterm birth have a high incidence of neurodevelopmental impairment which is not explained by currently understood brain abnormalities. The aim of this study was to test the hypothesis that the neurodevelopmental abilities of 2-year-old children who were born preterm and who had no evidence of focal abnormality on conventional MR imaging were consistently linearly related to specific local changes in white matter microstructure. We studied 33 children, born at a median (range) gestational age of 28(+5) (24(+4)-32(+1)) weeks. The children were recruited as infants from the Neonatal Intensive Care Unit at Queen Charlotte's and Hammersmith Hospital in the early neonatal period and imaged at a median corrected age of 25.5 (24-27) months. The children underwent diffusion tensor imaging to measure fractional anisotropy (FA) as a measure of tissue microstructure, and neurodevelopmental assessment using the Griffiths Mental Development Scales [giving an overall developmental quotient (DQ) and sub-quotients scores for motor, personal-social, hearing-language, eye-hand coordination and performance scales] at 2 years corrected age. Tract-based spatial statistics with linear regression analysis of voxel-wise cross-subject statistics were used to assess the relationship between FA and DQ/sub-quotient scores and results confirmed by reduced major axis regression of regions with significant correlations. We found that DQ was linearly related to FA values in parts of the corpus callosum; performance sub-scores to FA values in the corpus callosum and right cingulum; and eye-hand coordination sub-scores to FA values in the cingulum, fornix, anterior commissure, corpus callosum and right uncinate fasciculus. This study shows that specific neurodevelopmental impairments in infants born preterm are precisely related to microstructural abnormalities in particular regions of cerebral white matter which are consistent between individuals. FA may aid prognostication and provide a biomarker for therapeutic or mechanistic studies of preterm brain injury. PMID:18952670

Counsell, Serena J; Edwards, A David; Chew, Andrew T M; Anjari, Mustafa; Dyet, Leigh E; Srinivasan, Latha; Boardman, James P; Allsop, Joanna M; Hajnal, Joseph V; Rutherford, Mary A; Cowan, Frances M

2008-12-01

341

Depressive symptoms and white matter dysfunction in retired NFL players with concussion history  

PubMed Central

Objective: To determine whether correlates of white matter integrity can provide general as well as specific insight into the chronic effects of head injury coupled with depression symptom expression in professional football players. Method: We studied 26 retired National Football League (NFL) athletes who underwent diffusion tensor imaging (DTI) scanning. Depressive symptom severity was measured using the Beck Depression Inventory II (BDI-II) including affective, cognitive, and somatic subfactor scores (Buckley 3-factor model). Fractional anisotropy (FA) maps were processed using tract-based spatial statistics from FSL. Correlations between FA and BDI-II scores were assessed using both voxel-wise and region of interest (ROI) techniques, with ROIs that corresponded to white matter tracts. Tracts demonstrating significant correlations were further evaluated using a receiver operating characteristic curve that utilized the mean FA to distinguish depressed from nondepressed subjects. Results: Voxel-wise analysis identified widely distributed voxels that negatively correlated with total BDI-II and cognitive and somatic subfactors, with voxels correlating with the affective component (p < 0.05 corrected) localized to frontal regions. Four tract ROIs negatively correlated (p < 0.01) with total BDI-II: forceps minor, right frontal aslant tract, right uncinate fasciculus, and left superior longitudinal fasciculus. FA of the forceps minor differentiated depressed from nondepressed athletes with 100% sensitivity and 95% specificity. Conclusion: Depressive symptoms in retired NFL athletes correlate negatively with FA using either an unbiased voxel-wise or an ROI-based, tract-wise approach. DTI is a promising biomarker for depression in this population.

Strain, Jeremy; Didehbani, Nyaz; Cullum, C. Munro; Mansinghani, Sethesh; Conover, Heather; Kraut, Michael A.; Womack, Kyle B.

2013-01-01

342

Microstructural White Matter Changes, Not Hippocampal Atrophy, Detect Early Amnestic Mild Cognitive Impairment  

PubMed Central

Background Alzheimer’s disease (AD) is generally considered to be characterized by pathology in gray matter of the brain, but convergent evidence suggests that white matter degradation also plays a vital role in its pathogenesis. The evolution of white matter deterioration and its relationship with gray matter atrophy remains elusive in amnestic mild cognitive impairment (aMCI), a prodromal stage of AD. Methods We studied 155 cognitively normal (CN) and 27 ‘late’ aMCI individuals with stable diagnosis over 2 years, and 39 ‘early’ aMCI individuals who had converted from CN to aMCI at 2-year follow up. Diffusion tensor imaging (DTI) tractography was used to reconstruct six white matter tracts three limbic tracts critical for episodic memory function - the fornix, the parahippocampal cingulum, and the uncinate fasciculus; two cortico-cortical association fiber tracts - superior longitudinal fasciculus and inferior longitudinal fasciculus; and one projection fiber tract - corticospinal tract. Microstructural integrity as measured by fractional anisotropy (FA), mean diffusivity (MD), radial diffusivity (RD) and axial diffusivity (AxD) was assessed for these tracts. Results Compared with CN, late aMCI had lower white matter integrity in the fornix, the parahippocampal cingulum, and the uncinate fasciculus, while early aMCI showed white matter damage in the fornix. In addition, fornical measures were correlated with hippocampal atrophy in late aMCI, whereas abnormality of the fornix in early aMCI occurred in the absence of hippocampal atrophy and did not correlate with hippocampal volumes. Conclusions Limbic white matter tracts are preferentially affected in the early stages of cognitive dysfunction. Microstructural degradation of the fornix preceding hippocampal atrophy may serve as a novel imaging marker for aMCI at an early stage.

Zhuang, Lin; Sachdev, Perminder S.; Trollor, Julian N.; Reppermund, Simone; Kochan, Nicole A.; Brodaty, Henry; Wen, Wei

2013-01-01

343

Tissue Transglutaminase in Marmoset Experimental Multiple Sclerosis: Discrepancy between White and Grey Matter  

PubMed Central

Infiltration of leukocytes is a major pathological event in white matter lesion formation in the brain of multiple sclerosis (MS) patients. In grey matter lesions, less infiltration of these cells occur, but microglial activation is present. Thus far, the interaction of ?-integrins with extracellular matrix proteins, e.g. fibronectin, is considered to be of importance for the influx of immune cells. Recent in vitro studies indicate a possible role for the enzyme tissue Transglutaminase (TG2) in mediating cell adhesion and migration. In the present study we questioned whether TG2 is present in white and grey matter lesions observed in the marmoset model for MS. To this end, immunohistochemical studies were performed. We observed that TG2, expressed by infiltrating monocytes in white matter lesions co-expressed ?1-integrin and is located in close apposition to deposited fibronectin. These data suggest an important role for TG2 in the adhesion and migration of infiltrating monocytes during white matter lesion formation. Moreover, in grey matter lesions, TG2 is mainly present in microglial cells together with some ?1-integrin, whereas fibronectin is absent in these lesions. These data imply an alternative role for microglial-derived TG2 in grey matter lesions, e.g. cell proliferation. Further research should clarify the functional role of TG2 in monocytes or microglial cells in MS lesion formation.

Espitia Pinzon, Nathaly; Stroo, Esther; 't Hart, Bert A.; Bol, John G. J. M.; Drukarch, Benjamin

2014-01-01

344

White Matter Integrity Linked To Functional Impairments in Aging and Early Alzheimer's Disease  

PubMed Central

Background Alzheimer’s disease (AD) is associated with changes in cerebral white matter (WM) but the functional significance of such findings is not yet established. We hypothesized that diffusion tensor imaging (DTI) might reveal links between regional WM changes and specific neuropsychologically and psychophysically defined impairments in early AD. Methods Older adult control subjects (OA, n=18) and mildly impaired AD patients (n=14) underwent neuropsychological and visual perceptual testing along with DTI of cerebral WM. DTI yielded factional anisotropy (FA) and mean diffusivity () maps for nine ROIs in three brain regions that were then compared to the performance measures. Results AD patients showed non-significant trends toward lower FAs in the posterior region’s callosal and sub-cortical ROIs. However, posterior callosal FA was significantly correlated with verbal fluency and figural memory impairments, whereas posterior subcortical FA was correlated with delayed verbal memory, figural memory, and optic flow perceptual impairments. Conclusions WM changes in early AD are concentrated in posterior cerebral areas with distributions that correspond to specific functional impairments. DTI can be used to assess regional pathology related to individual’s deficits in early AD.

Kavcic, Voyko; Ni, Hongyan; Zhu, Tong; Zhong, Jianhui; Duffy, Charles J.

2008-01-01

345

Improving MRI differentiation of gray and white matter in epileptogenic lesions based on nonlinear feedback.  

PubMed

A new method for enhancing MRI contrast between gray matter (GM) and white matter (WM) in epilepsy surgery patients with symptomatic lesions is presented. This method uses the radiation damping feedback interaction in high-field MRI to amplify contrast due to small differences in resonance frequency in GM and WM corresponding to variations in tissue susceptibility. High-resolution radiation damping-enhanced (RD) images of in vitro brain tissue from five patients were acquired at 14 T and compared with corresponding conventional T(1)-, T(2) (*)-, and proton density (PD)-weighted images. The RD images yielded a six times better contrast-to-noise ratio (CNR = 44.8) on average than the best optimized T(1)-weighted (CNR = 7.92), T(2) (*)-weighted (CNR = 4.20), and PD-weighted images (CNR = 2.52). Regional analysis of the signal as a function of evolution time and initial pulse flip angle, and comparison with numerical simulations confirmed that radiation damping was responsible for the observed signal growth. The time evolution of the signal in different tissue regions was also used to identify subtle changes in tissue composition that were not revealed in conventional MR images. RD contrast is compared with conventional MR methods for separating different tissue types, and its value and limitations are discussed. PMID:16941616

Huang, Susie Y; Wolahan, Stephanie M; Mathern, Gary W; Chute, Dennis J; Akhtari, Massoud; Nguyen, Snow T; Huynh, My N; Salamon, Noriko; Lin, Yung-Ya

2006-10-01

346

Associations of white matter integrity and cortical thickness in patients with schizophrenia and healthy controls.  

PubMed

Typical brain development includes coordinated changes in both white matter (WM) integrity and cortical thickness (CT). These processes have been shown to be disrupted in schizophrenia, which is characterized by abnormalities in WM microstructure and by reduced CT. The aim of this study was to identify patterns of association between WM markers and cortex-wide CT in healthy controls (HCs) and patients with schizophrenia (SCZ). Using diffusion tensor imaging and structural magnetic resonance imaging data of the Mind Clinical Imaging Consortium study (130 HC and 111 SCZ), we tested for associations between (a) fractional anisotropy in selected manually labeled WM pathways (corpus callosum, anterior thalamic radiation, and superior longitudinal fasciculus) and CT, and (b) the number of lesion-like WM regions ("potholes") and CT. In HC, but not SCZ, we found highly significant negative associations between WM integrity and CT in several pathways, including frontal, temporal, and occipital brain regions. Conversely, in SCZ the number of WM potholes correlated with reduced CT in the left lateral temporal gyrus, left fusiform, and left lateral occipital brain area. Taken together, we found differential patterns of association between WM integrity and CT in HC and SCZ. Although the pattern in HC can be explained from a developmental perspective, the reduced gray matter CT in SCZ patients might be the result of focal but spatially heterogeneous disruptions of WM integrity. PMID:23661633

Ehrlich, Stefan; Geisler, Daniel; Yendiki, Anastasia; Panneck, Patricia; Roessner, Veit; Calhoun, Vince D; Magnotta, Vincent A; Gollub, Randy L; White, Tonya

2014-05-01

347

Multi-exponential T2, Magnetization Transfer and Quantitative Histology in White Matter Tracts of Rat Spinal Cord  

PubMed Central

Quantitative MRI measures of multi-exponential T2 relaxation (MET2) and magnetization transfer (qMT) were acquired from six samples of excised and fixed rat spinal cord and compared with quantitative histology. MRI and histology data were analyzed from six white matter tracts, each of which possessed unique micro-anatomical characteristics (axon diameter and myelin thickness, in particular) but a relatively constant volume fraction of myelin. The results indicated that MET2 characteristics varied substantially with variation of microanatomy while the qMT characteristics remained close to constant. The most-often cited MET2 metric, myelin water fraction (MWF) varied by almost a factor of 2 between two regions with myelin volume fractions that differed by only ? 12 %. Based on the quantitative histology, the proposed explanation for this variation was inter-compartmental water exchange, which caused the underestimation of MWF and T2 values and is, presumably, a greater factor in white matter regions where axons are small and myelin is thin. In contrast to the MET2 observations, qMT metrics were relatively constant across white matter tracts and concluded to be relatively insensitive to inter-compartmental water exchange.

Dula, Adrienne N.; Gochberg, Daniel F.; Valentine, Holly L.; Valentine, William M.; Does, Mark D.

2009-01-01

348

Persistent homological sparse network approach to detecting white matter abnormality in maltreated children: MRI and DTI multimodal study.  

PubMed

We present a novel persistent homological sparse network analysis framework for characterizing white matter abnormalities in tensor-based morphometry (TBM) in magnetic resonance imaging (MRI). Traditionally TBM is used in quantifying tissue volume change in each voxel in a massive univariate fashion. However, this obvious approach cannot be used in testing, for instance, if the change in one voxel is related to other voxels. To address this limitation of univariate-TBM, we propose a new persistent homological approach to testing more complex relational hypotheses across brain regions. The proposed methods are applied to characterize abnormal white matter in maltreated children. The results are further validated using fractional anisotropy (FA) values in diffusion tensor imaging (DTI). PMID:24505679

Chung, Moo K; Hanson, Jamie L; Lee, Hyekyoung; Adluru, Nagesh; Alexander, Andrew L; Davidson, Richard J; Pollak, Seth D

2013-01-01

349

A schizophrenia risk gene, ZNF804A, is associated with brain white matter microstructure.  

PubMed

Genome-wide association studies have provided strong evidence for association of the SNP rs1344706 in the ZNF804A gene with schizophrenia and bipolar disorder. Neuroimaging studies have suggested that variation at rs1344706 may be associated with neural endophenotypes such as white matter volumes and densities. However, analyses of white matter microstructure using diffusion tensor imaging (DTI) have produced conflicting results. We examined the association between rs1344706 and white matter microstructure in 107 healthy individuals using tract-based spatial statistics (TBSS). TBSS analysis showed significant association between the risk allele and lower fractional anisotropy in the corpus callosum, left forceps minor, and right parietal white matter (p<.05; FWE corrected). Post-hoc analyses indicated that this association was largely driven by alterations in radial diffusivity, consistent with an effect of genotype on myelination. In light of the strong DTI evidence for white matter microstructural abnormalities in schizophrenia, the current results implicate a potential mechanism for schizophrenia risk formation by ZNF804A rs1344706 genotype. PMID:24685285

Ikuta, T; Peters, B D; Guha, S; John, M; Karlsgodt, K H; Lencz, T; Szeszko, P R; Malhotra, A K

2014-05-01

350

Risk factors of migraine-related brain white matter hyperintensities: an investigation of 186 patients.  

PubMed

Brain white matter hyperintensities are more prevalent in migraine patients than in the general population, but the pathogenesis and the risk factors of these hyperintensities are not fully elucidated. The authors analyzed the routine clinical data of 186 migraine patients who were referred to the Outpatient Headache Department of the Department of Neurology, Medical School, University of Pécs, Hungary between 2007 and 2009: 58 patients with white matter hyperintensities and 128 patients without white matter hyperintensities on 3 T MRI. Significant associations between the presence of white matter hyperintensities and longer disease duration (14.4 vs. 19.9 years, p = 0.004), higher headache frequency (4.1 vs. 5.5 attacks/month, p = 0.017), hyperhomocysteinemia (incidence of hyperintensity is 9/9 = 100%, p = 0.009) and thyroid gland dysfunction (incidence of hyperintensity is 8/14 = 57.1%, p = 0.038) were found. These data support the theory that both the disease duration and the attack frequency have a key role in the formation of migraine-related brain white matter hyperintensities, but the effects of comorbid diseases may also contribute to the development of the hyperintensities. PMID:21331756

Trauninger, Anita; Leél-Ossy, Eszter; Kamson, David Olayinka; Pótó, László; Aradi, Mihály; Kövér, Ferenc; Imre, Marianna; Komáromy, Hedvig; Erdélyi-Botor, Szilvia; Patzkó, Agnes; Pfund, Zoltán

2011-02-01

351

Brain White Matter Abnormality in a Newborn Infant with Congenital Adrenal Hyperplasia  

PubMed Central

Several studies have described brain white matter abnormalities on magnetic resonance imaging (MRI) in children and adults with congenital adrenal hyperplasia (CAH), while the brain MRI findings of newborn infants with CAH have not been clarified. We report a newborn boy with CAH who presented brain white matter abnormality on MRI. He was diagnosed as having salt-wasting CAH with a high 17-OHP level at neonatal screening and was initially treated with hydrocortisone at 8 days of age. On day 11 after birth, he had a generalized tonic seizure. No evidence of serum electrolyte abnormalities was observed. Brain MRI revealed white matter abnormalities that consisted of bilateral small diffuse hyperintensities on T1-weighted images with slightly low intensity on T2-weighted images in the watershed area. Several factors associated with brain white matter abnormalities in adults with CAH, such as increasing age, hypertension, diabetes and corticosteroid replacement, were not applicable. Although the cause of the phenomenon in this case is unclear, brain white matter abnormality could be observed in newborn infants with CAH as well as in adult patients.

Kaga, Akimune; Saito-hakoda, Akiko; Uematsu, Mitsugu; Kamimura, Miki; Kanno, Junko; Kure, Shigeo; Fujiwara, Ikuma

2013-01-01

352

Tract Probability Maps in Stereotaxic Spaces: Analyses of White Matter Anatomy and Tract-Specific Quantification  

PubMed Central

Diffusion tensor imaging (DTI) is an exciting new MRI modality that can reveal detailed anatomy of the white matter. DTI also allows us to approximate the 3D trajectories of major white matter bundles. By combining the identified tract coordinates with various types of MR parameter maps, such as T2 and diffusion properties, we can perform tract-specific analysis of these parameters. Unfortunately, 3D tract reconstruction is marred by noise, partial volume effects, and complicated axonal structures. Furthermore, changes in diffusion anisotropy under pathological conditions could alter the results of 3D tract reconstruction. In this study, we created a white matter parcellation atlas based on probabilistic maps of 11 major white matter tracts derived from the DTI data from 28 normal subjects. Using these probabilistic maps, automated tract-specific quantification of fractional anisotropy and mean diffusivity were performed. Excellent correlation was found between the automated and the individual tractography-based results. This tool allows efficient initial screening of the status of multiple white matter tracts.

Hua, Kegang; Zhang, Jiangyang; Wakana, Setsu; Jiang, Hangyi; Li, Xin; Reich, Daniel S.; Calabresi, Peter A.; Pekar, James J.; van Zijl, Peter C. M.; Mori, Susumu

2009-01-01