Age differences in functional connectivity and dedifferentiation of category representations

Abstract

With advancing age, the distinctiveness of neural representations of information declines. While the finding of this so-called age-related neural dedifferentiation in category-selective neural regions is well-described, how neural dedifferentiation manifests at the level of large-scale functional networks is less understood. Furthermore, the relationship between age-related changes in network organization and dedifferentiation is unknown. Here, we investigated age-related neural dedifferentiation of category-selective regions as well as whole-brain functional networks. We additionally examined age differences in connectivity of category-selective regions to the rest of the brain. Younger and older adults viewed blocks of face and house stimuli while performing memory encoding and retrieval in the fMRI scanner. We found an age-related decline in neural distinctiveness for faces in the fusiform gyrus (FG) and for houses in the parahippocampal gyrus (PHG). Functional connectivity analyses revealed age-related dedifferentiation of global network structure as well as age differences in the connectivity profiles to category-selective regions. Together, our findings suggest that age-related neural dedifferentiation manifests both in regional categorical representations as well as in whole- brain functional networks. HighlightsO_LICategory representations are less distinctive, or dedifferentiated, in older adults C_LIO_LIFunctional networks are less segregated in older adults C_LIO_LIOlder adults reveal less connectivity between fusiform gyrus and visual cortices C_LI