Age-related changes in prefrontal cortex activity are associated with behavioural deficits in both temporal and spatial context memory retrieval in older adults

Abstract 

Aging is associated with decrements in both spatial and temporal context retrieval. Functional neuroimaging studies of young adults suggest that there are differences in left versus right lateral prefrontal cortex (PFC) contributions to spatial versus temporal source (recency) retrieval, respectively. The goal of the current study was to determine if age-related decreases in temporal and spatial context retrieval are due to common or distinct changes in PFC function. To address this goal we conducted an event-related functional magnetic resonance imaging (fMRI) study in which young and older adults performed recognition, recency and spatial context retrieval tasks using face stimuli to identify event-related PFC regions associated with these retrieval tasks in both age groups. Our behavioural results indicated that older adults did not differ on recognition performance, but did exhibit a deficit in both context retrieval tasks, compared to young adults. The fMRI results suggest that age-related deficits in both spatial and temporal context retrieval may be linked to functional changes in right dorsolateral and left medial anterior PFC (APFC) function. In addition, based on brain-behaviour correlations in older adults, our results imply that older adults attempt to compensate for these deficits by engaging left dorsolateral PFC during spatial context retrieval and right APFC during temporal context retrieval.

Keywords: Aging, Prefrontal cortex, Temporal context memory, Spatial source memory and fMRI