Neural Reinstatement of Overlapping Memories in Young and Older Adults

摘要

When we update our episodic memories with new information,mnemonic competition between old and new memoriesmay result because of the presence of shared features. Behavioralstudies suggest that this competition can lead to proactiveinterference, resulting in unsuccessful memory updating, particularlyfor older adults. It is difficult with behavioral data aloneto measure the reactivation of old, overlapping memories duringretrieval and its impact on memory for new memories.Here, we applied encoding–retrieval representational similarity(ERS) analysis to EEG data to estimate event-specific encodingrelatedneural reinstatement of old associations during theretrieval of new ones and its impact on memory for new associationsin young and older adults. Our results showed thatolder adults’ new associative memory performance was morenegatively impacted by proactive interference from old memoriesthan that of young adults. In both age groups, ERS for oldassociative memories was greater for trials for which new associativememories were forgotten than remembered. In contrast,ERS for new associative memories was greater when they wereremembered than forgotten. In addition, older adults showedrelatively attenuated target (i.e., new associates) and lure (i.e.,old associates) ERS effects compared to younger adults. Collectively,these results suggest that the neural reinstatement ofinterfering memories during retrieval contributes to proactiveinterference across age, whereas overall attenuated ERS effectin older adults might reflect their reduced memory fidelity.