Effects of aging on task- and stimulus-related cerebral attention networks.

Interactions between a dorsal attention network (DAN) and a ventral attention cerebral network (VAN) have been reported in young participants during attention or short-term memory (STM) tasks. Because it remains an underinvestigated question, age effects on DAN and VAN activity and their functional balance were explored during performance of an STM task. Older and younger groups showed similar behavioral patterns of results. At the cerebral level, DAN activation increased as a function of increasing STM load in both groups, suggesting preserved activity in DAN during healthy aging. Age-related over-recruitment in regions of the DAN in the higher task load raised the question of compensation attempt versus less efficient use of neural resources in older adults. Lesser decrease of VAN activation with increasing load and decreased stimulus-driven activation in the VAN, especially in the higher load, in older participants suggested age-related reduced response in the VAN. However, functional connectivity measures showed that VAN was still functionally connected to the DAN in older participants.