Mindwandering propensity modulates episodic memory consolidation

Abstract

Research into strategies that can combat episodic memory decline in healthy older adults has gained widespread attention over the years. Evidence suggests that a short period of rest immediately after learning can enhance memory consolidation, as compared to engaging in cognitive tasks. However, a recent study in younger adults has shown that post-encoding engagement in a working memory task leads to the same degree of memory consolidation as from post-encoding rest. Here, we tested whether this finding can be extended to older adults. Using a delayed recognition test, we compared the memory consolidation of word–picture pairs learned prior to 9 min of rest or a 2-Back working memory task, and examined its relationship with executive functioning and mindwandering propensity. Our results show that (1) similar to younger adults, memory for the word–picture associations did not differ when encoding was followed by post-encoding rest or 2-Back task and (2) older adults with higher mindwandering propensity retained more word–picture associations encoded prior to rest relative to those encoded prior to the 2-Back task, whereas participants with lower mindwandering propensity had better memory performance for the pairs encoded prior to the 2-Back task. Overall, our results indicate that the degree of episodic memory consolidation during both active and passive post-encoding periods depends on individual mindwandering tendency.Electronic supplementary materialThe online version of this article (10.1007/s40520-019-01251-1) contains supplementary material, which is available to authorized users.

Targeted Memory Reactivation during Mind-Wandering in Younger and Older Adults

“…Indeed, Craig and colleagues (2016) demonstrated that wakeful rest exhibited beneficial effects on cognitive map accuracy for both younger and older adults and Alber et al (2014) showed that wakeful rest benefited both amnestic patients and healthy controls on prose 1 One might argue that wakeful rest simply provides less interference than the distractor task. However, several pieces of literature have indicated that distractor tasks that do not engage episodic memory processes also allow for consolidation (see Varma et al, 2018;Varma et al, 2019).…”

“…The results of this study suggest that wakeful rest may benefit memory via a consolidation process supported by slow, oscillatory EEG activity and increased MW related to offline memory replay 2 . However, given the substantial variability in individuals' MW contents during wakeful rest periods (see Brokaw et al, 2016;Varma et al, 2019), one might wonder whether thoughts could be directly influenced to enhance memory reactivation during wakeful rest periods. Indeed, several targeted memory reactivation studies have investigated this issue.…”

“…Few studies in the extant literature have explored the possible benefits of MW in the context of aging and memory consolidation. However, one study by Varma et al (2019) examined whether a brief 9-minute post-encoding period of wakeful rest may combat older adults' declines in episodic memory and to what extent MW propensity may serve a role in this memory decline. Older adult participants were first asked to study a list of picture-word pairs.…”

“…Participants with greater MW propensity showed the largest benefit in memory performance following the rest period compared to the 2-back period. The authors argued that the degree to which episodic memory consolidation occurred during the postencoding wakeful rest period may depend on individual differences in MW propensity and that MW may assist in episodic memory formation and consolidation similar to memory reactivation during sleep (Varma et al, 2019).…”

“…Thus, it seems that MW may facilitate memory consolidation via mechanisms (possibly replay) similar to those that operate during sleep. Nevertheless, Brokaw et al (2016) and Varma et al (2019) are limited in several respects. First, neither study included both younger and older adults to compare memory performance and MW to address the issue of age-related changes in consolidation.…”