Memory consolidation during rest forms shortcuts in a cognitive map

Abstract

AbstractRest and sleep not only strengthen existing memories but also reorganise memories to generate new knowledge that extends beyond direct experience. However, it remains unclear bothhowmemories are reorganised and the effect of this reorganisation on behaviour. Here, to resolve this issue we designed a novel protocol to casually manipulate memory consolidation during rest using awake, contextual targeted memory reactivation (TMR). We found that promoting memory consolidation during rest reorganises memories byforming ‘shortcuts’ between memorieswhich have not been experienced together. These shortcuts in memory extend beyond direct experience to facilitate our ability to make novel inferences. However, these shortcuts impair our ability to flexibly update memories in response to rapid changes in the environment. These findings reveal how memories are reorganised during awake rest to construct a cognitive map of our environment that sets a trade-off between efficient and flexible behaviour.