Cerebral Cortex Advance Access published online on December 28, 2007
Cerebral Cortex, doi:10.1093/cercor/bhm243
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The Effects of Aging on the Neural Correlates of Subjective and Objective Recollection
1 Medical Research Council, Cognition and Brain Sciences Unit, Cambridge CB2 2QQ, UK, 2 Wales Institute of Cognitive Neuroscience and School of Psychology, Cardiff University, Cardiff CF10 3AT, UK
Address correspondence to Audrey Duarte, PhD, School of Psychology, Georgia Institute of Technology, 654 Cherry Street, Atlanta, GA 30332-0170, USA. Email: audrey.duarte{at}psych.gatech.edu.
High-functioning older adults can exhibit normal recollection when measured subjectively, via "remember" judgments, but not when measured objectively, via source judgments, whereas low-functioning older adults exhibit impairments for both measures. A potential explanation for this is that typical subjective and objective tests of recollection necessitate different processing demands, supported by distinct brain regions, and that deficits in these tests are observed according to the degree of age-related changes in these regions. Here, we used event-related functional magnetic resonance imaging to measure the effects of aging on neural correlates of subjective and objective measures of recollection, in young, high-functioning (Old-High) and low-functioning (Old-Low) older adults. Behaviorally, the Old-High group showed intact subjective ("remember" judgments) but impaired objective recollection (for 1 of 2 spatial or temporal sources), whereas the Old-Low group was impaired on both measures. Imaging data showed changes in parietal subjective recollection effects in the Old-Low group and in lateral frontal objective recollection effects in both older adult groups. Our results highlight the importance of examining performance variability in older adults and suggest that differential effects of aging on brain regions are associated with different patterns of performance on tests of subjective and objective recollection.
Key Words: aging familiarity fMRI frontal recollection