Age-related Differences in Agenda-driven Monitoring of Format and Task Information

Age-related source memory deficits may arise, in part, from changes in the agenda-driven processes that control what features of events are relevant during remembering. Using fMRI, we compared young and older adults on tests assessing source memory for format (picture, word) or encoding task (self-, other-referential), as well as on old–new recognition. Behaviorally, relative to old–new recognition, older adults showed disproportionate and equivalent deficits on both source tests compared to young adults. At encoding, both age groups showed expected activation associated with format in posterior visual processing areas, and with task in medial prefrontal cortex. At test, the groups showed similar selective, agenda-related activity in these representational areas. There were, however, marked age differences in the activity of control regions in lateral and medial prefrontal cortex and lateral parietal cortex. Results of correlation analyses were consistent with the idea that young adults had greater trial-by-trial agenda-driven modulation of activity (i.e., greater selectivity) than did older adults in representational regions. Thus, under selective remembering conditions where older adults showed clear differential regional activity in representational areas depending on type of test, they also showed evidence of disrupted frontal and parietal function and reduced item-by-item modulation of test-appropriate features. This pattern of results is consistent with an age-related deficit in the engagement of selective reflective attention. Normal aging is associated with a disproportionate decrement in the ability to correctly recollect specific features of events (source memory), relative to less specific forms of memory such as old–new recognition The use of neuroimaging in source memory studies with healthy older adults is beginning to yield important information about the relative impact of aging on the various, intertwined factors involved in source memory (e.g., encoding features and binding them together, controlled reflective attention to particular features during remembering), but there is still much to be learned. In particular, little is known about age-related changes in the neural correlates of selective, agenda-driven processes engaged during remembering—that is, those processes involved in determining which features are sought, revived, and used in making a specific memory attribution (see Johnson, Hashtroudi, and Lindsay (1993), Mitchell and Johnson (2009), for further discussion and reviews). This is the focus of the current study. Source memory is related to encoding activity in representa-tional regions associated with the processing of specific features, such as perceptual processing of color or location consistent with the context reinstatement hypothesis (Tulving and Thomson, 1973), the extent to …