0248 STUDYING SLEEP STAGE SPECIFICITY OF EMOTIONAL MEMORY CONSOLIDATION USING TARGETED MEMORY REACTIVATION

Abstract

A growing body of evidence indicate that sleep plays a role in emotional processing, including consolidation of emotionally salient memories. However, the roles of different sleep stages in emotional memory consolidation are not clear. Recent studies have shown that memory reactivation using external cues during specific sleep stages can enhance sleep-dependent memory consolidation. In this study, we aimed to investigate the sleep stage specificity for emotional memory consolidation by using a sleep-dependent spatial task and targeted memory reactivation (TMR). Participants were healthy adults between the ages of 18–30. During the computerized task, pictures with aversive content appeared in different locations while an associated sound played in the background. After a learning period, participants were tested for their memory of picture locations prior to (T1) and after (T2) a daytime nap. During nap, a subset of the sounds was replayed during slow wave sleep (SWS) or rapid eye movement (REM) sleep. Change in error in locating the pictures from T1 to T2 were compared between the reactivated (REA) and non-reactivated (non-REA) stimuli within and between SWS and REM conditions. Results are preliminary, as we continue to recruit participants in both groups. In SWS (n=7), there was significantly smaller error at T2 in non-REA (t=5.545, p=0.01), and a strong trend towards significantly smaller increase in error (T2-T1) in the same group (t=2.363, p=0.056). In REM (n=10), there was significantly smaller error at T2 (t=2.476, p=0.035), and a smaller numerical (T2-T1; t=2.653, p=0.026) and percentage ((T2-T1)/T1; t=2.779, p=0.021) increase in error in non-REA. We observed a different pattern compared to the majority of previous TMR studies which used neutral stimuli and reported improvement in memory for reactivated stimuli or no effects. Our results suggest that reactivation of emotional memories and neutral memories may have contrasting effects on sleep-dependent memory consolidation. N/A.