scholarly journals Age-related Differences in White Matter Integrity in Healthy Human Brain: Evidence from Structural Mri and Diffusion Tensor Imaging

2016 ◽  
Vol 9 ◽  
pp. MRI.S39666 ◽  
Author(s):  
Rishu Rathee ◽  
V.P. Subramanyam Rallabandi ◽  
Prasun K. Roy
Keyword(s):  
Diffusion Tensor Imaging ◽  
White Matter ◽  
Spatial Statistics ◽  
Diffusion Tensor ◽  
Mean Diffusivity ◽  
Middle Aged ◽  
Healthy Human ◽  
Aged Group ◽  
Age Related ◽  
Tract Based Spatial Statistics

The aim is to investigate the relationship between microstructural white matter (WM) diffusivity indices and macrostructural WM volume (WMV) among healthy individuals (20–85 years). Whole-brain diffusion measures were calculated from diffusion tensor imaging using FMRIB software library while WMV was estimated through voxel-based morphometry, and voxel-based analysis was carried out using tract-based spatial statistics. Our results revealed that mean diffusivity, axial diffusivity, and radial diffusivity had shown good correlation with WMV but not for fractional anisotropy (FA). Voxel-wise tract-based spatial statistics analysis for FA showed a significant decrease in four regions for middle-aged group compared to young-aged group, in 22 regions for old-aged group compared to middle-aged group, and in 26 regions for old-aged group compared to young-aged group ( P < 0.05). We found significantly lower WMV, FA, and mean diffusivity values in females than males and inverted-U trend for FA in males. We conclude differential age- and gender-related changes for structural WMV and WM diffusion indices.

scholarly journals Structural brain connectivity in children with developmental dyscalculia

2021 ◽  
Author(s):  
Nazife Ayyildiz ◽  
Frauke Beyer ◽  
Sertac Ustun ◽  
Emre H. Kale ◽  
Oyku Mance Calisir ◽  
...  
Keyword(s):  
Diffusion Tensor Imaging ◽  
White Matter ◽  
Spatial Statistics ◽  
Diffusion Tensor ◽  
Neurodevelopmental Disorder ◽  
Probabilistic Tractography ◽  
Developmental Dyscalculia ◽  
Minus Sign ◽  
Tract Based Spatial Statistics ◽  
Anterior Thalamic Radiation

Developmental dyscalculia (DD) is a neurodevelopmental disorder specific to arithmetic learning even with normal intelligence and age-appropriate education. Difficulties often persist from childhood through adulthood. Underlying neurobiological mechanisms of DD, however, are poorly understood. This study aimed to identify possible structural connectivity alterations in DD. We evaluated 10 children with pure DD (11.3 plus-or-minus sign 0.7 years) and 16 typically developing (TD) peers (11.2 plus-or-minus sign 0.6 years) using diffusion tensor imaging. We first assessed white matter microstructure with tract-based spatial statistics. Then we used probabilistic tractography to evaluate tract lengths and probabilistic connectivity maps in specific regions. At whole brain level, we found no significant microstructural differences in white matter between children with DD and TD peers. Also, seed-based connectivity probabilities did not differ between groups. However, we did find significant differences in regions-of-interest tracts which had previously been related to math ability in children. The major findings of our study were reduced white matter coherence and shorter tract lengths of the left superior longitudinal/arcuate fasciculus and left anterior thalamic radiation in the DD group. Furthermore, lower white matter coherence and shorter pathways corresponded with the lower math performance as a result of the correlation analyses. These results from regional analyses indicate that learning, memory and language-related pathways in the left hemisphere might underlie DD. Keywords: Mathematical learning disability, diffusion tensor imaging, superior longitudinal fasciculus, anterior thalamic radiation, probabilistic tractography, tract-based spatial statistics

scholarly journals Tract Specificity of Age Effects on Diffusion Tensor Imaging Measures of White Matter Health

2021 ◽  
Vol 13 ◽  
Author(s):  
Stephanie Matijevic ◽  
Lee Ryan
Keyword(s):  
Older Adults ◽  
Diffusion Tensor Imaging ◽  
Individual Differences ◽  
White Matter ◽  
Diffusion Tensor ◽  
Mean Diffusivity ◽  
White Matter Integrity ◽  
White Matter Tracts ◽  
Apoe Ε4 ◽  
Age Related

Well-established literature indicates that older adults have poorer cerebral white matter integrity, as measured through diffusion tensor imaging (DTI). Age differences in DTI have been observed widely across white matter, although some tracts appear more sensitive to the effects of aging than others. Factors like APOE ε4 status and sex may contribute to individual differences in white matter integrity that also selectively impact certain tracts, and could influence DTI changes in aging. The present study explored the degree to which age, APOE ε4, and sex exerted global vs. tract specific effects on DTI metrics in cognitively healthy late middle-aged to older adults. Data from 49 older adults (ages 54–92) at two time-points separated by approximately 2.7 years were collected. DTI metrics, including fractional anisotropy (FA) and mean diffusivity (MD), were extracted from nine white matter tracts and global white matter. Results showed that across timepoints, FA and MD increased globally, with no tract-specific changes observed. Baseline age had a global influence on both measures, with increasing age associated with lower FA and higher MD. After controlling for global white matter FA, age additionally predicted FA for the genu, callosum body, inferior fronto-occipital fasciculus (IFOF), and both anterior and posterior cingulum. Females exhibited lower global FA on average compared to males. In contrast, MD was selectively elevated in the anterior cingulum and superior longitudinal fasciculus (SLF), for females compared to males. APOE ε4 status was not predictive of either measure. In summary, these results indicate that age and sex are associated with both global and tract-specific alterations to DTI metrics among a healthy older adult cohort. Older women have poorer white matter integrity compared to older men, perhaps related to menopause-induced metabolic changes. While age-related alterations to white matter integrity are global, there is substantial variation in the degree to which tracts are impacted, possibly as a consequence of tract anatomical variability. The present study highlights the importance of accounting for global sources of variation in DTI metrics when attempting to investigate individual differences (due to age, sex, or other factors) in specific white matter tracts.

Sign in / Sign up

Export Citation Format

Share Document