This is the fifth renewal of a longstanding project focused on age-related declines in the ability to remember specific past personal experiences, commonly referred to episodic memory. Episodic memory plays an important role in supporting adaptive cognitive functions that require the ability to retrieve and flexibly recombine episodic information, such as imagining novel future experiences or making inferences that link distinct events. However, cognitive aging research has only recently begun to examine the consequences of episodic memory decline for these adaptive functions. Several studies, for example, have documented that reduced episodic retrieval in healthy older adults and patients with Alzheimer's disease is associated with declines in imagining details about future experiences (episodic simulation). Functional magnetic resonance imaging (fMRI) studies have revealed that episodic simulation is associated with a core brain network that includes medial prefrontal, temporal, and parietal cortices as well as lateral temporal and parietal cortices, but little is known about how age-associated changes in episodic simulation are related to the functions of specific regions within this core network. The main goals of the proposed research are to use both neuroimaging and cognitive/behavioral paradigms to identify the effects of aging on the neural mechanisms and cognitive consequences of episodic processes involved in recombining elements of past experiences to construct novel event representations. The first set of experiments will test hypotheses regarding the effects of aging on the neural mechanisms that support flexible recombination of episodic details when participants imagine novel future experiences by applying new fMRI paradigms and procedures developed in recent research: 1) an episodic specificity induction that increases the generation of episodic details during future imagining in both old and young adults; 2) an analytic procedure that allows the identification of core network regions as a function of the timecourse of their engagement during simulation and the amount of information that is simulated; and 3) a novel repetition suppression procedure that has documented that particular core network regions demonstrate repetition-related reductions in neural activity that are linked with specific components of simulated events. The second set of experiments will examine the effects of aging on cognitive consequences of flexible recombination using a new procedure that provides evidence for a link between flexible recombination processes used to make associative inferences about the relations among distinct events and subsequent memory distortions. Several experiments have shown that young adults commit more source memory errors after successful than unsuccessful associative inferences, but preliminary data indicate that older adults do not show this effect. The proposed experiments will explore the conditions under which this striking age difference occurs and test theoretical accounts of why it occurs. Taken together, the proposed studies should provide important new insights into the nature of constructive memory and future imagining with aging.
Statement Memory is fundamentally important to numerous aspects of our everyday lives, and disorders of memory that impair everyday functions are commonly observed in normal aging and Alzheimer's disease. Imagining or mentally simulating events that might occur in the future is crucial to adaptive function, important to planning for the future, and disrupted in healthy aging and Alzheimer's disease. Our work should yield novel insights that will enhance understanding of both neural and cognitive aspects of age-related changes in constructive memory and future imagining.
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