Understanding population-specific structural differences in brain aging

Understanding distinct neurological aging patterns across various populations is vital in the context of a globally aging populace. This study seeks to unravel the structural variations in the aging brain, taking into consideration different ethnic backgrounds. MRI data from Indian, Chinese, Japanese, and Caucasian populations were analyzed using a two-pronged approach. Initially, a group analysis was performed involving tissue segmentation through FSL-FAST, examining gray matter (GM), white matter (WM), and cerebrospinal fluid (CSF). Subsequently, a continuous model-based analysis was employed, defining aging as a diffeomorphic transformation, which facilitated a detailed intra- and inter-population analysis, and examined both global anatomy and age-dependent distances of each population in comparison to the Indian population. The analysis revealed distinct aging trajectories in the different populations. Notably, the Japanese demographic exhibited a delayed onset of GM reductions and ventricular expansion. Additionally, we observed a significant hemispherical asymmetry in the expansion rate in the left brain's CSF-filled region across all populations. Detailed insights into the spatial distribution of brain deformations over time were obtained, with particular focus on anatomical changes relative to a reference time point. Our findings are a step towards a nuanced understanding of the aging process, opening avenues for personalized age-related healthcare strategies rooted in a understanding of population-specific neurological aging trajectories.