0066 Reactivating Remote Emotional Memory Before Sleep Impacts Dream Affect, but Not Dream Content

Recalling a personal emotional memory before sleep did not make people dream about that memory more than writing about a neutral topic. However, dreams after recalling an angry memory were rated as more negative in emotion, especially the first dream reported. This suggests that while pre-sleep experiences rarely appear directly in dream content, emotional stimuli can influence the emotional tone of dreams, possibly reflecting emotional memory consolidation or a general effect of pre-sleep mood on dream emotion.

Study at a glance

Abstract

Abstract Introduction Completing a learning task just before sleep often induces task-related dreams. This is thought to reflect the consolidation of recently formed memories in the sleeping brain. However, this literature has focused almost exclusively on how recent experiences newly introduced before sleep are incorporated into dreams. It is unknown whether and how remote memories may also be reactivated during sleep and incorporated into dreaming. Methods We aimed to experimentally trigger participants to dream about a remote emotional episodic memory. Just before a nap, participants (N = 34) completed the Autobiographical Emotional Memory Task (AEMT). In this task, participants were asked to recall and write about “the one situation that has made you the most angry you have been in your life”. In a control condition (within-subjects), participants instead wrote about designing a new college course. During the subsequent nap, participants were awoken up to four times to report their dream experiences. Following the nap, participants rated the extent to which they felt each dream was related to the earlier writing task, and rated the emotional valence of each dream. Results The AEMT elicited negative mood (pre-nap PANAS-negative score in AEMT vs. control condition: t(33)= 6.20, p< 0.0001). Although participants rated some dreams as related to the pre-sleep writing task in both conditions, dreams were not significantly more related following the AEMT, as compared to the control condition (Wald test: χ2(1)=2.67, p=0.10). However, dream emotion was significantly more negative following the AEMT, relative to the control condition (Wald test: χ2(1)=5.15, p=0.02). This effect was strongest for the first dream reported. Conclusion Recalling a personal memory had no greater influence on dream content than writing about a neutral, memory-nrelated topic. At the same time, recalling a remote, emotional memory before sleep did affect the emotional valence of dreams. These data echo observations dating back to the 1960s suggesting that while transparent representations of presleep experience in dreams are rare, emotional stimuli do reliably influence dream affect. This might reflect emotional memory consolidation, or be a more general influence of pre-sleep mood on subsequent emotion during sleep. Support (if any)