Age-related differences in cerebral morphology and microstructure in rhesus macaques

The rhesus macaque presents a promising model for translational research into human brain aging due to this species' long lifespan and close phylogenic relationship. We conducted a cross-sectional study identifying microstructural and morphological biomarkers of aging in a cohort of 37 healthy animals (18F/19M, aged 5-28 years), using high-resolution T2-weighted (T2w) and diffusion-weighted (DW) images. Using Tensor Based Morphometry, significant age-associated regional brain atrophy was observed in some areas of the frontal and parietal cortex, as well as the striatum. Additionally, age-associated differences in white matter diffusion were observed in several brain regions, including frontal and temporal white matter areas, and regions of the internal capsule and corpus callosum. Taken together, the results demonstrate that morphological and microstructural age-related differences can be disclosed in cortical, striatal, and thalamic regions, as well as in the white matter fiber pathways connecting these areas, using high-resolution DTI and MRI.