Selective Relationships Between Sensory System White Matter Connectivity And Sensory And Cognitive Function In Aged Macaques

Abstract

Normative aging results in deficits in both auditory and visual function, along with degradation of select cognitive functions. Studies have shown that sensory function is a predictor of late-life cognitive abilities, though the neurobiological base of this relationship is unclear. Previously our group found that the connectivity of medial temporal lobe-associated white matter was related to better auditory processing abilities and temporal lobe-dependent cognitive functions. This study concluded that shared impacts of aging on temporal lobe structures could account for the selectivity in these relationships. However, little is known about the association between sensory system white matter connectivity and sensory and cognitive function with age. In this study, adult and aged bonnet macaque monkeys were behaviorally characterized and evaluated for auditory and visual function. Measures of auditory and visual system white matter connectivity were extracted using diffusion MRI and probabilistic tractography. We found that higher connectivity of callosal auditory fibers was associated with better auditory function, and higher connectivity of the posterior forceps and optic radiation were associated with better visual function. Higher connectivity of auditory system white matter was associated with better performance on certain temporal-lobe dependent cognitive tasks. Our results support the idea that a shared impact of aging on temporal lobe structures could partially drive relationships between auditory processing and temporal lobe-dependent cognition.