Age-Related Gray and White Matter Changes in Normal Adult Brains

Abstract

Normal aging is associated with both structural changes in many brain regions and functional declines in several cognitive domains with advancing age. Advanced neuroimaging techniques enable explorative analyses of structural alterations that can be used as assessments of such age-related changes. Here we used voxel-based morphometry (VBM) to investigate regional and global brain volume differences among four groups of healthy adults from the IXI Dataset: older females (OF, mean age 68.35 yrs; n=69), older males (OM, 68.43 yrs; n=66), young females (YF, 27.09 yrs; n=71), and young males (YM, 27.91 yrs; n=71), using 3D T1-weighted MRI data. At the global level, we investigated the influence of age and gender on brain volumes using a two-way analysis of variance. With respect to gender, we used the Pearson correlation to investigate global brain volume alterations due to age in the older and young groups. At the regional level, we used a flexible factorial statistical test to compare the means of gray matter (GM) and white matter (WM) volume alterations among the four groups. We observed different patterns in both the global and regional GM and WM alterations in the young and older groups with respect to gender. At the global level, we observed significant influences of age and gender on global brain volumes. At the regional level, the older subjects showed a widespread reduction in GM volume in regions of the frontal, insular, and cingulate cortices compared to the young subjects in both genders. Compared to the young subjects, the older subjects showed a widespread WM decline prominently in the thalamic radiations, in addition to increased WM in pericentral and occipital areas. Knowledge of these observed brain volume differences and changes may contribute to the elucidation of mechanisms underlying aging as well as age-related brain atrophy and disease.

Whole Brain and Cranial Size Adjustments in Volumetric Brain Analyses of Sex- and Age-Related Trends

“…Ge Y et al described the adjusted WM volume changes during the lifespan-according to their observations, the WM volume increases approximately up to age 40, then decreases (Ge et al, 2002). Farokhian et al explained that it could be due to the ongoing maturation of the white matter during normal aging (Farokhian et al, 2017). Coming back to our results, it is worth noting that with the TBV adjustment the negative age dependence of the GM volume is more pronounced in the males, while in case of WM the age-related positive trend in the female group is weaker (Table 5, Figure 7).…”

Enhanced fitness relates to reduced cerebrovascular reactivity and perfusion in a sample of very healthy older adults

“…The impact of healthy aging on brain structure and function is an active field of research and the age group comparisons performed as part of this study are consistent with these existing results. Older adults were found to have a lower GMV volume as compared to young adults, similar to previous reports of age-related atrophy in GM [54][55][56] . Our findings of decreased CVR in older adults compared to young adults is also in line with previous research 32,33,39,57,58 , as are the findings of decreased resting CBF 32,33 .…”

Does age affect medial prefrontal functions? A behavioral investigation.

“…In the older age group sampled here, there is evidence to suggest deficits in conflict monitoring and response inhibition; two MPFC functions assessed by the AX-CPT and the Simon task, once the contributions of intelligence and processing speed are removed. In line with suggestions of anatomical shrinking (e.g., Farokhian et al, 2017), performance on tasks which tax the MPFC suggests that the associated functions are impaired with age alongside those associated with the DLPFC. Indeed, this study is the first that allows comparison between performance on tasks associated with dorsolateral, orbital, and medial PFC, within the same individuals.…”