scholarly journals Cerebral White Matter Myelination and Relations to Age, Gender, and Cognition: A Selective Review

2021 ◽  
Vol 15 ◽  
Author(s):  
Irina S. Buyanova ◽  
Marie Arsalidou
Keyword(s):  
White Matter ◽  
Cognitive Abilities ◽  
Brain Maturation ◽  
Cerebral White Matter ◽  
Childhood And Adolescence ◽  
Spatial And Temporal Patterns ◽  
Fiber Tracts ◽  
Selective Review ◽  
And Gender ◽  
Neuroimaging Techniques

White matter makes up about fifty percent of the human brain. Maturation of white matter accompanies biological development and undergoes the most dramatic changes during childhood and adolescence. Despite the advances in neuroimaging techniques, controversy concerning spatial, and temporal patterns of myelination, as well as the degree to which the microstructural characteristics of white matter can vary in a healthy brain as a function of age, gender and cognitive abilities still exists. In a selective review we describe methods of assessing myelination and evaluate effects of age and gender in nine major fiber tracts, highlighting their role in higher-order cognitive functions. Our findings suggests that myelination indices vary by age, fiber tract, and hemisphere. Effects of gender were also identified, although some attribute differences to methodological factors or social and learning opportunities. Findings point to further directions of research that will improve our understanding of the complex myelination-behavior relation across development that may have implications for educational and clinical practice.

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 Motor cortex gliomas induces microstructural changes of large fiber tracts revealed by TBSS

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Xiangdong Wang ◽  
Chunyao Zhou ◽  
Lei Wang ◽  
Yinyan Wang ◽  
Tao Jiang
Keyword(s):  
White Matter ◽  
Motor Cortex ◽  
Diffusion Tensor ◽  
Early Stage ◽  
Mean Diffusivity ◽  
Cerebral White Matter ◽  
Control Group ◽  
Fiber Tracts ◽  
3.0 T ◽  
White Matter Fiber Tracts

Abstract Gliomas grow and invade along white matter fiber tracts. This study assessed the effects of motor cortex gliomas on the cerebral white matter fiber bundle skeleton. The motor cortex glioma group included 21 patients, and the control group comprised 14 healthy volunteers. Both groups underwent magnetic resonance imaging-based 3.0 T diffusion tensor imaging. We used tract-based spatial statistics to analyze the characteristics of white matter fiber bundles. The left and right motor cortex glioma groups were analyzed separately from the control group. Results were statistically corrected by the family-wise error rate. Compared with the controls, patients with left motor cortex gliomas exhibited significantly reduced fractional anisotropy and an increased radial diffusivity in the corpus callosum. The alterations in mean diffusivity (MD) and the axial diffusivity (AD) were widely distributed throughout the brain. Furthermore, atlas-based analysis showed elevated MD and AD in the contralateral superior fronto-occipital fasciculus. Motor cortex gliomas significantly affect white matter fiber microstructure proximal to the tumor. The range of affected white matter fibers may extend beyond the tumor-affected area. These changes are primarily related to early stage tumor invasion.

Gerstmann Meets Geschwind

2011 ◽  
Vol 17 (6) ◽  
pp. 633-644 ◽  
Author(s):  
Andreas Kleinschmidt ◽  
Elena Rusconi
Keyword(s):  
White Matter ◽  
Clinical Symptoms ◽  
Cerebral White Matter ◽  
Focal Lesion ◽  
Cortical Lesions ◽  
White Matter Damage ◽  
Fiber Tract ◽  
Fiber Tracts ◽  
Behavioral Neurology ◽  
Clinical Phenomenology

That disconnection causes clinical symptoms is a very influential concept in behavioral neurology. Criteria for subcortical disconnection usually are symptoms that are distinct from those following cortical lesions and damage to a single, long-range fiber tract. Yet, a recent study combining functional magnetic resonance imaging and fiber tracking concluded that a focal lesion in left parietal white matter provides the only tenable explanation for pure Gerstmann’s syndrome, an enigmatic tetrad of acalculia, agraphia, finger agnosia, and left-right disorientation. Such a lesion would affect not only a single fiber tract but crossing or “kissing” of different fiber tracts and hence disconnect separate cortical networks. As fiber crossing is prominent in the cerebral white matter, the authors propose an extension to the subcortical disconnection framework that opens the door to ascribing a more diversified clinical phenomenology to white matter damage and ensuing disconnection than has been the case so far.

scholarly journals White matter of perinatally HIV infected older youths shows low frequency fluctuations that may reflect glial cycling

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Manoj K. Sarma ◽  
Amrita Pal ◽  
Margaret A. Keller ◽  
Tamara Welikson ◽  
Joseph Ventura ◽  
...  
Keyword(s):  
White Matter ◽  
Brain Activity ◽  
Low Frequency ◽  
Brain Regions ◽  
Cerebral White Matter ◽  
Frequency Fluctuations ◽  
And Gender ◽  
Latent Hiv ◽  
The Right ◽  
The Brain

AbstractIn perinatally HIV-infected (PHIV) children, neurodevelopment occurs in the presence of HIV-infection, and even with combination antiretroviral therapy (cART) the brain can be a reservoir for latent HIV. Consequently, patients often demonstrate long-term cognitive deficits and developmental delay, which may be reflected in altered functional brain activity. Our objective was to examine brain function in PHIV on cART by quantifying the amplitude of low frequency fluctuations (ALFF) and regional homogeneity (ReHo). Further, we studied ALFF and ReHo changes with neuropsychological performance and measures of immune health including CD4 count and viral loads in the HIV-infected youths. We found higher ALFF and ReHo in cerebral white matter in the medial orbital lobe for PHIV (N = 11, age mean ± sd = 22.5 ± 2.9 years) compared to controls (N = 16, age = 22.5 ± 3.0 years), with age and gender as co-variates. Bilateral cerebral white matter showed increased spontaneous regional activity in PHIV compared to healthy controls. No brain regions showed lower ALFF or ReHo in PHIV compared to controls. Higher log10 viral load was associated with higher ALFF and ReHo in PHIV in bilateral cerebral white matter and right cerebral white matter respectively after masking the outcomes intrinsic to the brain regions that showed significantly higher ALFF and ReHo in the PHIV compared to the control. Reductions in social cognition and abstract thinking in PHIV were correlated with higher ALFF at the left cerebral white matter in the left medial orbital gyrus and higher ReHo at the right cerebral white matter in the PHIV patients. Although neuroinflammation and associated neuro repair were not directly measured, the findings support their potential role in PHIV impacting neurodevelopment and cognition.

Track-based study of age and gender difference in maturation and senescence of cerebral white matter.

NeuroImage ◽  
2009 ◽  
Vol 47 ◽  
pp. S151
Author(s):  
P Kochunov ◽  
DE Williamson ◽  
D Glahn ◽  
JL Lancaster ◽  
J Blangero ◽  
...  
Keyword(s):  
White Matter ◽  
Gender Difference ◽  
Cerebral White Matter ◽  
Age And Gender ◽  
And Gender

scholarly journals White Matter Microstructure in Superior Longitudinal Fasciculus Associated with Spatial Working Memory Performance in Children

2011 ◽  
Vol 23 (9) ◽  
pp. 2135-2146 ◽  
Author(s):  
Martin Vestergaard ◽  
Kathrine Skak Madsen ◽  
William F. C. Baaré ◽  
Arnold Skimminge ◽  
Lisser Rye Ejersbo ◽  
...  
Keyword(s):  
Working Memory ◽  
Individual Differences ◽  
White Matter ◽  
Posterior Parietal Cortex ◽  
Spatial Working Memory ◽  
Childhood And Adolescence ◽  
Superior Longitudinal Fasciculus ◽  
Fiber Tract ◽  
Fiber Tracts ◽  
Parietal Cortices

During childhood and adolescence, ongoing white matter maturation in the fronto-parietal cortices and connecting fiber tracts is measurable with diffusion-weighted imaging. Important questions remain, however, about the links between these changes and developing cognitive functions. Spatial working memory (SWM) performance improves significantly throughout the childhood years, and several lines of evidence implicate the left fronto-parietal cortices and connecting fiber tracts in SWM processing. Here we report results from a study of 76 typically developing children, 7 to 13 years of age. We hypothesized that better SWM performance would be associated with increased fractional anisotropy (FA) in a left fronto-parietal network composed of the superior longitudinal fasciculus (SLF), the regional white matter underlying the dorsolateral pFC, and the posterior parietal cortex. As hypothesized, we observed a significant association between higher FA in the left fronto-parietal network and better SWM skills, and the effect was independent of age. This association was mainly accounted for by variability in left SLF FA and remained significant when FA measures from global fiber tracts or right SLF were included in the model. Further, the effect of FA in left SLF appeared to be mediated primarily by decreasing perpendicular diffusivity. Such associations could be related to individual differences among children in the architecture of fronto-parietal connections and/or to differences in the pace of fiber tract development. Further studies are needed to determine the contributions of intrinsic and experiential factors to the development of functionally significant individual differences in fiber tract structure.

scholarly journals A hierarchical watershed model of fluid intelligence in childhood and adolescence

2018 ◽  
Author(s):  
D. Fuhrmann ◽  
I. L. Simpson-Kent ◽  
J. Bathelt ◽  
R. A. Kievit ◽  
Keyword(s):  
White Matter ◽  
Cognitive Abilities ◽  
Structural Equation ◽  
Fluid Intelligence ◽  
Childhood And Adolescence ◽  
Watershed Model ◽  
Early Puberty ◽  
Specific Knowledge ◽  
Independent Effects ◽  
The Relationship

AbstractFluid intelligence is the capacity to solve novel problems in the absence of task-specific knowledge, and is highly predictive of outcomes like educational attainment and psychopathology. Here, we modelled the neurocognitive architecture of fluid intelligence in two cohorts: CALM (N = 551, aged 5 - 17 years) and NKI-RS (N = 335, aged 6 - 17 years). We used multivariate Structural Equation Modelling to test a preregistered watershed model of fluid intelligence. This model predicts that white matter contributes to intermediate cognitive phenotypes, like working memory and processing speed, which, in turn, contribute to fluid intelligence. We found that this model performed well for both samples and explained large amounts of variance in fluid intelligence (R2CALM = 51.2%, R2NKI-RS = 78.3%). The relationship between cognitive abilities and white matter differed with age, showing a dip in strength around ages 7 - 12 years. This age-effect may reflect a reorganization of the neurocognitive architecture around pre- and early puberty. Overall, these findings highlight that intelligence is part of a complex hierarchical system of partially independent effects.

scholarly journals Neurocognitive reorganization between crystallized intelligence, fluid intelligence and white matter microstructure in two age-heterogeneous developmental cohorts

2019 ◽  
Author(s):  
Ivan L. Simpson-Kent ◽  
Delia Fuhrmann ◽  
Joe Bathelt ◽  
Jascha Achterberg ◽  
Gesa Sophia Borgeest ◽  
...  
Keyword(s):  
White Matter ◽  
Cognitive Ability ◽  
Cognitive Abilities ◽  
Structural Equation ◽  
Fluid Intelligence ◽  
Childhood And Adolescence ◽  
Pivotal Phase ◽  
Cross Sectional ◽  
White Matter Microstructure ◽  
Age Range

AbstractDespite the reliability of intelligence measures in predicting important life outcomes such as educational achievement and mortality, the exact configuration and neural correlates of cognitive abilities remain poorly understood, especially in childhood and adolescence. Therefore, we sought to elucidate the factorial structure and neural substrates of child and adolescent intelligence using two cross-sectional, developmental samples (CALM: N=551 (N=165 imaging), age range: 5-18 years, NKI-Rockland: N=337 (N=65 imaging), age range: 6-18 years). In a preregistered analysis, we used structural equation modelling (SEM) to examine the neurocognitive architecture of individual differences in childhood and adolescent cognitive ability. In both samples, we found that cognitive ability in lower and typical-ability cohorts is best understood as two separable constructs, crystallized and fluid intelligence, which became more distinct across development, in line with the age differentiation hypothesis. Further analyses revealed that white matter microstructure, most prominently the superior longitudinal fasciculus, was strongly associated with crystallized (gc) and fluid (gf) abilities. Finally, we used SEM trees to demonstrate evidence for developmental reorganization of gc and gf and their white matter substrates such that the relationships among these factors dropped between 7-8 years before increasing around age 10. Together, our results suggest that shortly before puberty marks a pivotal phase of change in the neurocognitive architecture of intelligence.

scholarly journals A Hierarchical Watershed Model of Fluid Intelligence in Childhood and Adolescence

2019 ◽  
Vol 30 (1) ◽  
pp. 339-352 ◽  
Author(s):  
Delia Fuhrmann ◽  
Ivan L Simpson-Kent ◽  
Joe Bathelt ◽  
Rogier A Kievit ◽  
◽  
...  
Keyword(s):  
White Matter ◽  
Cognitive Abilities ◽  
Structural Equation ◽  
Fluid Intelligence ◽  
Equation Modeling ◽  
Childhood And Adolescence ◽  
Watershed Model ◽  
Early Puberty ◽  
Independent Effects ◽  
The Relationship

AbstractFluid intelligence is the capacity to solve novel problems in the absence of task-specific knowledge and is highly predictive of outcomes like educational attainment and psychopathology. Here, we modeled the neurocognitive architecture of fluid intelligence in two cohorts: the Centre for Attention, Leaning and Memory sample (CALM) (N = 551, aged 5–17 years) and the Enhanced Nathan Kline Institute—Rockland Sample (NKI-RS) (N = 335, aged 6–17 years). We used multivariate structural equation modeling to test a preregistered watershed model of fluid intelligence. This model predicts that white matter contributes to intermediate cognitive phenotypes, like working memory and processing speed, which, in turn, contribute to fluid intelligence. We found that this model performed well for both samples and explained large amounts of variance in fluid intelligence (R2CALM = 51.2%, R2NKI-RS = 78.3%). The relationship between cognitive abilities and white matter differed with age, showing a dip in strength around ages 7–12 years. This age effect may reflect a reorganization of the neurocognitive architecture around pre- and early puberty. Overall, these findings highlight that intelligence is part of a complex hierarchical system of partially independent effects.

Abstract T MP118: Microinfarct Disruption of Cerebral White Matter: A Longitudinal Diffusion Tractography Analysis

Stroke ◽  
2014 ◽  
Vol 45 (suppl_1) ◽  
Author(s):  
Eitan Auriel ◽  
Yael Reijmar ◽  
Brian Edlow ◽  
Panagiotis Fotiadis ◽  
Sergi Martinez-Ramirez ◽  
...  
Keyword(s):  
White Matter ◽  
Cognitive Decline ◽  
Longitudinal Analysis ◽  
Diffusion Tensor ◽  
Mean Diffusivity ◽  
Cerebral White Matter ◽  
Amyloid Angiopathy ◽  
Longitudinal Diffusion ◽  
Short Segment ◽  
Fiber Tracts

Introduction: Cerebral microinfarcts (CMI) are associated with cognitive decline in clinico-pathological studies. Acute CMI can be detected by diffusion-weighted imaging (DWI). We prospectively evaluated the effect of incidental CMI on white matter (WM) ultrastructure using longitudinal diffusion tensor imaging (DTI)-based tractography. Methods: Nine incidental DWI lesions were identified in six subjects (all males, age 67±9 years, mean pre-to-post lesional scan interval 19±4 months). All patients were diagnosed with probable cerebral amyloid angiopathy and underwent at least three MRIs as part of a prospective study. Silent DWI lesions were observed on the middle scan, enabling longitudinal analysis. Control regions-of-interest (ROIs) were generated in the contralateral hemisphere using semi-automated coregistration, and the lesion/control ROIs were coregistered to the pre- and post-lesional scans. DTI parameters [fractional anisotropy (FA); mean diffusivity (MD)] were measured within each ROI, along a short-segment of WM fiber tracts (within 6mm of the ROI), and along the entire tract. For the lesional scan, we compared DTI parameters between lesion and control ROIs. For the longitudinal analysis, we compared the ratio of lesion-to-control FA and MD at the pre-lesional and post-lesional scans. Results: On the lesional scan, FA within the lesion ROI was significantly lower than in the control ROI (0.28±0.13 vs. 0.40±0.20, p=0.04) and MD was non-significantly reduced in the lesion ROI versus the control ROI (p=0.09). A significant decline within lesion ROI in FA ratio (1.22±0.45 vs. 0.91±0.439, p=0.04) and an increase in MD ratio (0.96±0.14 vs. 1.25±0.37, p=0.02) were observed between the pre-lesional and post-lesional scans. There was no difference in FA ratio or MD ratio for the short segment or entire tracts at the time of the lesion and in the longitudinal analysis. Conclusion: We demonstrate persistent microstructural alterations of WM caused by incidental DWI lesions. Although these alterations do not extend outside the lesional ROI to associated fiber tracts, their accumulation over time may explain their association with cognitive decline.

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