One night of sleep is insufficient to achieve sleep-to-forget emotional decontextualisation processes

Abstract

Neutral memories unbind from their emotional acquisition context when sleep is allowed the night after learning and testing takes place after two additional nights of sleep. However, mood-dependent memory (MDM) effects are not abolished after a restricted sleep episode mostly featuring non rapid-eye-movement (NREM) or rapid-eye-movement (REM) sleep. Here, we tested whether (1) one night of sleep featuring several NREM-REM sleep cycles is sufficient to suppress MDM effects and (2) a neutral mood is a sufficiently contrasting state to induce MDM effects, i.e. interfere with the recall of information learned in happy or sad states. Results disclosed MDM effects both in the post-learning sleep and wake conditions, with better recall in congruent than incongruent emotional contexts. Our findings suggest that the emotional unbinding needs several consecutive nights of sleep to be complete, and that even subtle mood changes are sufficient to produce MDM effects.

Keywords:

• Mood-dependent memory
• Sleep
• Memory consolidation
• Mood
• Interference

The authors thank Svenia Schreiner for help in data acquisition and Rachel Leproult for her careful proofreading of English language. Gaétane Deliens is Research Fellows at the Belgian Fonds National de la Recherche Scientifique (FNRS).

This study was supported by FRS-FNRS (Belgian National Fund of Scientific Research—Fonds National Belge de la Recherche Scientifique) [grant CC 1.5.184.10F].

The authors thank Svenia Schreiner for help in data acquisition and Rachel Leproult for her careful proofreading of English language. Gaétane Deliens is Research Fellows at the Belgian Fonds National de la Recherche Scientifique (FNRS).

This study was supported by FRS-FNRS (Belgian National Fund of Scientific Research—Fonds National Belge de la Recherche Scientifique) [grant CC 1.5.184.10F].