Decreasing integration within face network and segregation beyond the face network in the aging brain.

Face processing is known to decline in older adults; however, a clear understanding of the brain networks behind this cognitive decline is still lacking. In this study, we investigated the neural correlates of the declined face processing with aging from a resting-state brain network perspective. Nineteen healthy old adults and 22 young adults were recruited and underwent two functional magnetic resonance imaging (fMRI) scanning sessions (i.e., resting-state and localizer task) and two behavioral tests (face matching and symbol-form matching). We examined age-related alterations in resting-state functional connectivity (FC) within face network as well as between face network and other networks, and tested their associations with behavioral performance of face and symbol-form processing. We found that (a) compared with young adults, old adults exhibited decreased FC between face-selective regions (fusiform face area and occipital face area), but increased FC between face-selective regions and non-face-selective regions; (b) these age-related FC alterations were correlated with individuals' behavioral performance of face and symbol-form processing. Collectively, these findings suggest the declines of face processing are associated with a mixture of decreased integration within the face network and segregation beyond the face network in the aging brain, and provide evidence for a neural basis of cognitive aging in face processing from an intrinsic brain network perspective.