Targeted memory reactivation during non-rapid eye movement sleep enhances neutral, but not negative, components of memory

Abstract

Emotionally salient components of memory are preferentially remembered at the expense of accompanying neutral information. This emotional memory trade-off is enhanced over time, and possibly sleep, though a process of memory consolidation. Sleep is believed to benefit memory through a process of memory reactivation during non-rapid eye movement sleep (NREM). Here, targeted memory reactivation (TMR) was used to manipulate the reactivation of negative and neutral memories during NREM sleep. Thirty-one participants encoded scenes containing either a negative or neutral object superimposed on an always neutral background. During NREM sleep, sounds associated with these scenes were replayed, and memory for scene components was tested the following morning. We found that TMR during NREM sleep improved memory for neutral, but not negative scene objects. This effect was associated with sleep spindle activity, with a larger spindle response following TMR cues predicting TMR effectiveness for neutral items only. These findings therefore do not suggest a role of NREM memory reactivation in enhancing the emotional memory trade-off across a 12-hour period but do align with growing evidence of spindle-mediated memory reactivation in service of neutral declarative memory.

Reactivating Positive Personality Traits During Sleep Promotes Positive Self-Referential Processing

“…During NREM sleep, cardinal neural oscillations such as slow oscillations (<1 Hz), delta waves (1–4 Hz) and the 12-16 Hz spindles are instrumental in mediating memory reactivation and consolidation (Born & Wilhelm, 2012; Rasch & Born, 2013; Antony et al, 2017; Klinzing et al, 2019; Schreiner et al, 2021; Petzka et al, 2022; Brodt et al, 2023). Specifically, in TMR, researchers repeatedly found that the cue-elicited delta and sigma EEG power changes predicted TMR benefits (Lehmann et al, 2016; Blume et al, 2017; Göldi et al, 2019; Denis & Payne, 2023; Liu et al, 2023; Schechtman et al, 2023; Xia et al, 2023). While these findings have significantly advanced our understanding, they remained silent on how propagation of sleep EEG oscillations may contribute to memory consolidation.…”