Aging and the neural correlates of source memory: over-recruitment and functional reorganization.
Behavioral evidence suggests that memory for context (i.e., source memory) is more vulnerable to age-related decline than item memory. It is not clear, however, whether this pattern reflects a specific age-related deficit in context memory or a more general effect of task difficulty. In the present study, we used event-related functional magnetic resonance imaging (fMRI) with healthy younger and older adults to dissociate the effects of age, task (item vs. source memory), and task difficulty (1 vs. 2 study presentations) on patterns of blood oxygen level-dependent (BOLD) signal changes during memory retrieval. Behavioral performance was similar in both age groups, but was sensitive to task and difficulty (item > source; easy > difficult). Data-driven multivariate analyses revealed age differences consistent with age-related overrecruitment of frontoparietal regions during difficult task conditions, and age-related functional reorganization in bilateral frontal and right-lateralized posterior regions that were sensitive to difficulty in younger adults, but to task (i.e., context demand) in older adults. These findings support the hypothesis of a specific context memory deficit in older adults.
Department of Psychology, Ryerson University, Toronto, Ontario, Canada. jspaniol@psych.ryerson.ca
Julia
J
Spaniol
Cheryl
C
Grady
D000328:Adult; D000368:Aged; D000375:Aging / Q000502:physiology*; D001921:Brain / Q000502:physiology*; D001931:Brain Mapping; D003657:Decision Making / Q000502:physiology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D061212:Memory, Episodic; D008875:Middle Aged; D011999:Recruitment, Neurophysiological / Q000502:physiology*; D055815:Young Adult