White-matter connectivity shapes visual and semantic representations in the aging brain

Abstract

Multiple lines of evidence indicate that aging is associated with a reduction in the quality of sensory information coupled with increased reliance on semantic information. Consistent with this evidence, functional MRI studies have repeatedly found that, compared to younger adults, older adults show weaker visual representations but stronger semantic representations. However, the factors that engender this visuo-semantic representational shift (VSRS) remain unclear. Here, we test whether structural connectivity within the representational network predicts these shifts. In the face of typical age-related declines in visual memory and structural connectivity, we find that structural connectivity (i) mediates age-related decline in perceptual representation, and (ii) supports semantic and perceptual mnemonic representations in older adults. These findings outline a potential mechanism of age-related perceptual processing declines and highlight the adaptability of the memory system with age.