Episodic memory, including autobiographical memory (AM) for our personal past, shows the earliest and steepest decline in healthy aging and Alzheimer's disease (AD). More recently, several lines of evidence have suggested that both remembering and imagining are supported by a constructive episodic memory system that allows the flexible recombination of details from past episodes into simulations of possible future events. Yet, there are scarce data on the cognitive and neural basis underlying AM and episodic simulation in healthy older adults or AD patients, which is a serious oversight to understanding abnormalities in the episodic memory system in aging. Moreover, patterns of decline in AM and episodic simulation may be due to separable underlying cognitive and neural changes in healthy aging vs. AD. Thus, better understanding these effects could help to differentiate healthy from pathological aging, and potentially contribute to biomarkers of disease. The goal of the proposed research is to elucidate the cognitive and neural mechanisms underlying AM and episodic simulation in healthy aging vs. AD. In the first study, participants will recall past memories and novel future events under varying levels of retrieval support in order to distinguish the contribution of strategic retrieval vs. declarative memory deficits in each group. In the second study, participants will recall past memories and episodic simulations elicited by personal photographs in order to determine the impact of more effective retrieval cues on group differences. Finally, in the third study, resting state functional MRI and structural MRI will be combined to determine the neural correlates of AM and episodic simulations in healthy older adults vs. AD. Collectively, the proposed project will reveal the cognitive and neural mechanisms underlying episodic simulation in AD and healthy older adults.
Elucidating the relationship between memory and episodic simulation in AD has the potential to provide novel interventions for slowing impairment and subsequently improving quality of life. The proposed project aims to provide an empirical foundation that will be critical for future clinical interventions in this devastating disease.
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