Age-related gray matter volume changes in the brain during non-elderly adulthood

Abstract

Previous magnetic resonance imaging (MRI) studies described consistent age-related gray matter (GM) reductions in the fronto-parietal neocortex, insula and cerebellum in elderly subjects, but not as frequently in limbic/paralimbic structures. However, it is unclear whether such features are already present during earlier stages of adulthood, and if age-related GM changes may follow non-linear patterns at such age range. This voxel-based morphometry study investigated the relationship between GM volumes and age specifically during non-elderly life (18-50 years) in 89 healthy individuals (48 males and 41 females). Voxelwise analyses showed significant (p<0.05, corrected) negative correlations in the right prefrontal cortex and left cerebellum, and positive correlations (indicating lack of GM loss) in the medial temporal region, cingulate gyrus, insula and temporal neocortex. Analyses using ROI masks showed that age-related dorsolateral prefrontal volume decrements followed non-linear patterns, and were less prominent in females compared to males at this age range. These findings further support for the notion of a heterogeneous and asynchronous pattern of age-related brain morphometric changes, with region-specific non-linear features.

Fig. 1

Results of the whole-brain search of significant correlations between gray matter (GM) volumes and age in the overall sample of healthy non-elderly individuals (n = 89) (at the Z > 3.09 threshold, corresponding to p < 0.001 and an extent threshold of 300 voxels). Foci of significance were overlaid on sagittal brain slices spatially normalized into an approximation to the Talairach and Tournoux stereotactic atlas (1988). The numbers associated with each frame represent standard coordinates in the x axis. (A) Foci of negative correlation without covariance for total GM volume (highlighted in blue), representing the atrophic changes that occur with the aging process. The right prefrontal cortex and left cerebellum are the most prominent areas of global brain volume reduction. (B) Areas of negative correlation with covariance for total GM volume (highlighted in blue) showed restricted areas of atrophy in the right prefrontal cortex and left cerebellum. (C) Foci of significant positive correlation with covariance for total GM volume (highlighted in yellow) indicating the brain regions where GM decrements did not occur in the same proportion as the overall degree of GM loss with aging, including: the entire extension of the cingulate gyrus, the amygdala-hippocampal complex, the parahippocampal gyrus and insula bilaterally, as well as the posterior temporal cortex and precuneus. Abbreviations: S, superior; I, inferior; R, right; L, left. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of the article.)

Fig. 2

Plots of gray matter versus age (including best fit regression lines) in the overall sample healthy individuals (n = 89). Mean gray matter volumes for each brain region were extracted from the spatially normalized images of each subject using standardized ROI masks, and corrected for the total amount of gray matter in the brain. Only regions in which at least one regression model was significant at the p < 0.05 threshold are represented (see Table 5 for details).

Fig. 3

Plots of gray matter versus age (including best fit regression lines) in male (n = 48) and female (n = 41) subgroups. Mean gray matter volumes for each brain region were extracted from the spatially normalized images of each subject using standardized ROI masks, and corrected for the total amount of gray matter in the brain. Only regions in which at least one regression model was significant for male or female subgroups at the p < 0.05 threshold are represented (see Table 5 for details).