scholarly journals Cortical atrophy and transcallosal diaschisis following isolated subcortical stroke

2019 ◽  
Vol 40 (3) ◽  
pp. 611-621 ◽  
Author(s):  
Bastian Cheng ◽  
Philipp Dietzmann ◽  
Robert Schulz ◽  
Marlene Boenstrup ◽  
Lutz Krawinkel ◽  
...  
Keyword(s):  
White Matter ◽  
Cortical Thickness ◽  
Diffusion Tensor ◽  
Brain Regions ◽  
White Matter Integrity ◽  
Cortical Atrophy ◽  
Fiber Tractography ◽  
Stroke Patients ◽  
Fiber Tracts ◽  
One Year

Following acute ischemic stroke, isolated subcortical lesions induce gray matter atrophy in anatomically connected, yet distant cortical brain regions. We expand on previous studies by analyzing cortical thinning in contralesional, homologous regions indirectly linked to primary stroke lesions via ipsilesional cortical areas. For this purpose, stroke patients were serially studied by magnetic resonance imaging (diffusion tensor imaging and high-resolution anatomical imaging) in the acute (days 3–5) and late chronic stage one year after stroke. We analyzed changes of gray and white matter integrity in 18 stroke patients (median age 68 years) with subcortical stroke. We applied probabilistic fiber tractography to identify brain regions connected to stroke lesions and contralesional homologous areas. Cortical thickness was quantified by semi-automatic measurements, and fractional anisotropy was analyzed. One year after stroke, significant decrease of cortical thickness was detected in areas connected to ischemic lesions (mean −0.15 mm; 95% CI −0.23 to −0.07 mm) as well as homologous contralateral brain regions (mean −0.13 mm; 95% CI −0.07 to −0.19 mm). We detected reduced white matter integrity of inter- and intrahemispheric fiber tracts. There were no significant associations with clinical recovery. Our results indicate that impact of subcortical lesions extends to homologous brain areas via transcallosal diaschisis.

scholarly journals Prediction of white matter integrity pattern in overweight and obese adults

2020 ◽  
Vol 79 (OCE2) ◽  
Author(s):  
Sussanne Reyes ◽  
Patricio Peirano ◽  
Betsy Lozoff ◽  
Cecilia Algarin
Keyword(s):  
White Matter ◽  
Cognitive Flexibility ◽  
Diffusion Tensor ◽  
Brain Regions ◽  
Normal Weight ◽  
White Matter Integrity ◽  
School Age ◽  
Loss Avoidance ◽  
Neurocognitive Tasks ◽  
The Relationship

Abstract IntroductionObesity has been associated with lower white matter integrity (WMI) in limbic brain regions, including the fornix. Both early decrease of WMI in the fornix (WMIf) and midlife obesity have been related to dementia incidence with advancing age. No studies have explored early cognitive predictors of WMIf in overweight-obese (OO) adults. Aim of this study was to compare OO and normal-weight (NW) participants with respect to (a) WMIf in adulthood and (b) the relationship between cognitive performance at school-age and in adolescence with WMIf in adulthood.MethodsParticipants were part of a cohort followed since infancy who underwent magnetic resonance imaging studies in adulthood (22.3 ± 1.3 years). Diffusion tensor imaging was performed and Tract Based Spatial Statistics (TBSS) was used to obtain fractional anisotropy (FA) skeleton; increased FA relates to greater WMI. A mask for the fornix was created (JHU-ICBM DTI-81 Atlas) and then used to extract the average FA for each individual. Participants also performed neurocognitive tasks: (a) school-age (10.3 ± 1.0 years): the trail making test comprises two conditions and time difference between conditions reflects cognitive flexibility; (b) adolescence (15.6 ± 0.5 years): incentive task that test the effect of incentives (reward, loss avoidance or neutral) on inhibitory control performance (correct responses latency). In adulthood, BMI was categorized as NW (≥ 18.5 to < 25.0 kg/m2) and OO (≥ 25.0 kg/m2) groups. A t-test and univariate GLM were conducted. Analysis were adjusted by sex and age-specific BMI z-scores.ResultsParticipants were 27 NW (41% female) and 41 OO (49% female). Compared to NW, OO participants showed decreased FA in the fornix (0.585 vs. 0.618, p < 0.05), i.e. lower WMIf. Differences were apparent in the relationship between cognitive flexibility at school-age (F = 2.9, p = 0.06) and loss avoidance latency in adolescence (F = 3.5, p < 0.05) with FA in the fornix in adulthood. Increased cognitive flexibility at school-age (β = 0.335, p < 0.05) and decreased loss avoidance latency in adolescence (β = -0.581, p < 0.001) were related to higher FA in the fornix in OO adults. No relationship resulted significant in NW adults.DiscussionPerformance in neurocognitive tasks at earlier developmental stages were related with WMIf only in OO adults, group characterized by decreased WMIf. Our results provide evidence regarding specific neurocognitive tasks with predictive value for WMIf alterations. Further, they could contribute to the understanding of neural mechanisms underlying obesity and also provide insight relative to neurodegenerative risk with advancing age.SupportFondecyt 11160671 and NIH HD33487.

Diffusion Tensor Imaging and Fiber Tractography

2009 ◽  
pp. 229-246
Author(s):  
Evanthia E. Tripoliti ◽  
Dimitrios I. Fotiadis ◽  
Konstantia Veliou
Keyword(s):  
Diffusion Tensor Imaging ◽  
White Matter ◽  
Diffusion Tensor ◽  
Brain Regions ◽  
Cerebral White Matter ◽  
Tissue Microstructure ◽  
Diffusion Weighted Images ◽  
Fiber Tracts ◽  
Diffusion Weighted ◽  
Magnetic Resonance Imaging Mri

Diffusion Tensor Imaging (DTI) is a magnetic resonance imaging (MRI) modality which can significantly improve our understanding of the brain structures and neural connectivity. DTI measures are thought to be representative of brain tissue microstructure and are particularly useful for examining organized brain regions, such as white matter tract areas. DTI measures the water diffusion tensor using diffusion weighted pulse sequences which are sensitive to microscopic random water motion. The resulting diffusion weighted images (DWI) display and allow quantification of how water diffuses along axes or diffusion encoding directions. This can help to measure and quantify the tissue’s orientation and structure, making it an ideal tool for examining cerebral white matter and neural fiber tracts. In this chapter the authors discuss the theoretical aspects of DTI, the information that can be extracted from DTI data, and the use of the extracted information for the reconstruction of fiber tracts and the diagnosis of a disease. In addition, a review of known fiber tracking algorithms is presented.

scholarly journals White matter degeneration in remote brain areas of stroke patients with motor impairment due to basal ganglia lesions

2021 ◽  
Author(s):  
Xuejin Cao ◽  
Zan Wang ◽  
Xiaohui Chen ◽  
Yanli Liu ◽  
Wei Wang ◽  
...  
Keyword(s):  
White Matter ◽  
Basal Ganglia ◽  
Structural Changes ◽  
Diffusion Tensor ◽  
Motor Impairment ◽  
Brain Regions ◽  
Stroke Patients ◽  
Brain Areas ◽  
Structural Network ◽  
Multivariate Pattern

Abstract Diffusion tensor imaging (DTI) studies have revealed distinct white matter characteristics of the brain following diseases. Beyond the lesion-symptom maps, stroke is characterized by extensive structural and functional alterations of brain areas remote to local lesions. Here, we further investigated the structural changes over a global level by using DTI data of ten ischemic stroke patients showing motor impairment due to basal ganglia lesions and 11 healthy controls. DTI data were processed to obtain fractional anisotropy (FA) maps, and multivariate pattern analysis (MVPA) was used to explore brain regions that play an important role in classification based on FA maps. The white matter (WM) structural network was constructed by the deterministic fiber-tracking approach. In comparison with the controls, the stroke patients showed FA reductions in the perilesional basal ganglia, brainstem, and bilateral frontal lobes. Using network-based statistics (NBS), we found a significant reduction in the WM subnetwork in stroke patients. We identified the patterns of WM degeneration affecting brain areas remote to the lesions, revealing the abnormal organization of the structural network in stroke patients, which may be helpful in understanding of the neural mechanisms underlying hemiplegia.

scholarly journals Changes in fronto-parieto-temporal connectivity following Do-As-I-Do imitation training in chimpanzees (Pan troglodytes)

2017 ◽  
Author(s):  
Sarah Pope ◽  
Jared Taglialatela ◽  
Sara Skiba ◽  
William D. Hopkins
Keyword(s):  
White Matter ◽  
Pan Troglodytes ◽  
Diffusion Tensor ◽  
Brain Regions ◽  
Mirror System ◽  
White Matter Integrity ◽  
Primate Species ◽  
Learning Abilities ◽  
Trained Subjects ◽  
Temporal Connectivity

Human imitation is supported by an underlying ‘mirror system’ principally composed of inferior frontal (IF), inferior parietal (IP), and superior temporal (ST) cortical regions. Across primate species, differences in fronto-parieto-temporal connectivity have been hypothesized to explain phylogenetic variation in imitative abilities. However, if and to what extent these regions are involved in imitation in non-human primates is unknown. We hypothesized that ‘Do As I Do’ (DAID) imitation training would enhance white matter integrity within and between fronto-parieto-temporal regions. To this end, four captive chimpanzees (Pan troglodytes) were trained to reproduce 23 demonstrated actions, while four age/sex-matched controls were trained to produce basic husbandry behaviors in response to manual cues. Diffusion tensor images were acquired before and after 600 minutes of training over an average of 112 days. Bilateral and asymmetrical changes in fronto-parieto-temporal white matter integrity were compared between DAID trained subjects and controls. We found that imitation trained subjects exhibited leftward shifts in both mean fractional anisotropy and tract strength asymmetry measures in brain regions within the mirror system. This is the first report of training-induced changes in white matter integrity in chimpanzees and suggests that fronto-parieto-temporal connectivity, particularly in the left hemisphere, may have facilitated the emergence of increasingly complex imitation learning abilities.

scholarly journals Decreased White Matter Integrity in Neuropsychologically Defined Mild Cognitive Impairment Is Independent of Cortical Thinning

2013 ◽  
Vol 19 (8) ◽  
pp. 925-937 ◽  
Author(s):  
Nikki H. Stricker ◽  
David H. Salat ◽  
Jessica M. Foley ◽  
Tyler A. Zink ◽  
Ida L. Kellison ◽  
...  
Keyword(s):  
Cognitive Impairment ◽  
Mild Cognitive Impairment ◽  
White Matter ◽  
Cortical Thickness ◽  
Gray Matter ◽  
Diffusion Tensor ◽  
A Priori ◽  
Hippocampal Volume ◽  
White Matter Integrity ◽  
White Matter Changes

AbstractImproved understanding of the pattern of white matter changes in early and prodromal Alzheimer's disease (AD) states such as mild cognitive impairment (MCI) is necessary to support earlier preclinical detection of AD, and debate remains whether white matter changes in MCI are secondary to gray matter changes. We applied neuropsychologically based MCI criteria to a sample of normally aging older adults; 32 participants met criteria for MCI and 81 participants were classified as normal control (NC) subjects. Whole-head high resolution T1 and diffusion tensor imaging scans were completed. Tract-Based Spatial Statistics was applied and a priori selected regions of interest were extracted. Hippocampal volume and cortical thickness averaged across regions with known vulnerability to AD were derived. Controlling for cortical thickness, the MCI group showed decreased average fractional anisotropy (FA) and decreased FA in parietal white matter and in white matter underlying the entorhinal and posterior cingulate cortices relative to the NC group. Statistically controlling for cortical thickness, medial temporal FA was related to memory and parietal FA was related to executive functioning. These results provide further support for the potential role of white matter integrity as an early biomarker for individuals at risk for AD and highlight that changes in white matter may be independent of gray matter changes. (JINS, 2013, 19, 1–13)

scholarly journals Changes in Frontoparietotemporal Connectivity following Do-As-I-Do Imitation Training in Chimpanzees (Pan troglodytes)

2018 ◽  
Vol 30 (3) ◽  
pp. 421-431 ◽  
Author(s):  
Sarah M. Pope ◽  
Jared P. Taglialatela ◽  
Sara A. Skiba ◽  
William D. Hopkins
Keyword(s):  
White Matter ◽  
Pan Troglodytes ◽  
Diffusion Tensor ◽  
Brain Regions ◽  
Mirror System ◽  
White Matter Integrity ◽  
Primate Species ◽  
Learning Abilities ◽  
Trained Subjects ◽  
Diffusion Tensor Images

Human imitation is supported by an underlying “mirror system” principally composed of inferior frontal, inferior parietal, and superior temporal cortical regions. Across primate species, differences in frontoparietotemporal connectivity have been hypothesized to explain phylogenetic variation in imitative abilities. However, if and to what extent these regions are involved in imitation in nonhuman primates is unknown. We hypothesized that “Do As I Do” (DAID) imitation training would enhance white matter integrity within and between frontoparietotemporal regions. To this end, four captive chimpanzees ( Pan troglodytes) were trained to reproduce 23 demonstrated actions, and four age-/sex-matched controls were trained to produce basic husbandry behaviors in response to manual cues. Diffusion tensor images were acquired before and after 600 min of training over an average of 112 days. Bilateral and asymmetrical changes in frontoparietotemporal white matter integrity were compared between DAID trained subjects and controls. We found that imitation trained subjects exhibited leftward shifts in both mean fractional anisotropy and tract strength asymmetry measures in brain regions within the mirror system. This is the first report of training-induced changes in white matter integrity in chimpanzees and suggests that frontoparietotemporal connectivity, particularly in the left hemisphere, may have facilitated the emergence of increasingly complex imitation learning abilities.

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

2010 ◽  
Vol 12 (4) ◽  
pp. 554-560 ◽  
Keyword(s):  
White Matter ◽  
Diffusion Tensor ◽  
Chronic Alcoholism ◽  
Emotional Dysregulation ◽  
Fiber Tractography ◽  
Fiber Tracts ◽  
Fiber Degradation ◽  
Clinical Impairment

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

scholarly journals Alterations in Cortical Thickness and White Matter Integrity in Mild-to-Moderate Communicating Hydrocephalic School-Aged Children Measured by Whole-Brain Cortical Thickness Mapping and DTI

2017 ◽  
Vol 2017 ◽  
pp. 1-6 ◽  
Author(s):  
Siyu Zhang ◽  
Xinjian Ye ◽  
Guanghui Bai ◽  
Yuchuan Fu ◽  
Chuanwan Mao ◽  
...  
Keyword(s):  
White Matter ◽  
Fractional Anisotropy ◽  
Cortical Thickness ◽  
Diffusion Tensor ◽  
Structural Mri ◽  
Middle Frontal Gyrus ◽  
White Matter Integrity ◽  
Communicating Hydrocephalus ◽  
Middle Temporal

Follow-up observation is required for mild-to-moderate hydrocephalic patients because of the potential damage to brain. However, effects of mild-to-moderate hydrocephalus on gray and white matter remain unclear in vivo. Using structural MRI and diffusion tensor imaging (DTI), current study compared the cortical thickness and white matter integrity between children with mild-to-moderate communicating hydrocephalus and healthy controls. The relationships between cortical changes and intelligence quota were also examined in patients. We found that cortical thickness in the left middle temporal and left rostral middle frontal gyrus was significantly lower in the hydrocephalus group compared with that of controls. Fractional anisotropy in the right corpus callosum body was significantly lower in the hydrocephalus group compared with that of controls. In addition, there was no association of cortical thinning or white matter fractional anisotropy with intelligence quota in either group. Thus, our findings provide clues to that mild-to-moderate hydrocephalus could lead to structural brain deficits especially in the middle temporal and middle frontal gyrus prior to the behavior changes.

Arterial Stiffness Is Associated with White Matter Disruption and Cognitive Impairment: A Community-Based Cohort Study

2021 ◽  
Vol 80 (2) ◽  
pp. 567-576
Author(s):  
Fei Han ◽  
Fei-Fei Zhai ◽  
Ming-Li Li ◽  
Li-Xin Zhou ◽  
Jun Ni ◽  
...  
Keyword(s):  
Cognitive Function ◽  
White Matter ◽  
Arterial Stiffness ◽  
Cognitive Decline ◽  
Sex Education ◽  
Diffusion Tensor ◽  
Mean Diffusivity ◽  
White Matter Injury ◽  
White Matter Integrity ◽  
Cross Sectional

Background: Mechanisms through which arterial stiffness impacts cognitive function are crucial for devising better strategies to prevent cognitive decline. Objective: To examine the associations of arterial stiffness with white matter integrity and cognition in community dwellings, and to investigate whether white matter injury was the intermediate of the associations between arterial stiffness and cognition. Methods: This study was a cross-sectional analysis on 952 subjects (aged 55.5±9.1 years) who underwent diffusion tensor imaging and measurement of brachial-ankle pulse wave velocity (baPWV). Both linear regression and tract-based spatial statistics were used to investigate the association between baPWV and white matter integrity. The association between baPWV and global cognitive function, measured as the mini-mental state examination (MMSE) was evaluated. Mediation analysis was performed to assess the influence of white matter integrity on the association of baPWV with MMSE. Results: Increased baPWV was significantly associated with lower mean global fractional anisotropy (β= –0.118, p < 0.001), higher mean diffusivity (β= 0.161, p < 0.001), axial diffusivity (β= 0.160, p < 0.001), and radial diffusivity (β= 0.147, p < 0.001) after adjustment of age, sex, and hypertension, which were measures having a direct effect on arterial stiffness and white matter integrity. After adjustment of age, sex, education, apolipoprotein E ɛ4, cardiovascular risk factors, and brain atrophy, we found an association of increased baPWV with worse performance on MMSE (β= –0.093, p = 0.011). White matter disruption partially mediated the effect of baPWV on MMSE. Conclusion: Arterial stiffness is associated with white matter disruption and cognitive decline. Reduced white matter integrity partially explained the effect of arterial stiffness on cognition.

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