The effect of sleep deprivation on retrieval of emotional memory: a behavioural study using film stimuli

Although the deleterious effects of sleep deprivation on memory consolidation are well documented, it is still unclear how the facilitating effect of emotions on memory consolidation processes could be modulated by the lack of sleep. In this study, we investigated the effects of sleep deprivation on episodic memory using emotional and non-emotional film stimuli. Forty-eight healthy subjects, divided into a sleep group (SG) and a sleep-deprived (SD) group, completed an Encoding and a Recall phase. Participants in the SD group were sleep deprived the night immediately following the Encoding phase, whereas the control group slept at home. The Recall phase was administered to all subjects 48 h after the Encoding. During the Encoding phase, six film clips of different valence (two positive, two neutral and two negative) were presented to the participants. During the Recall phase, episodic memory was assessed by a recognition task. Results showed that the SD group had a lower discrimination memory performance for all stimuli compared to the SG, confirming the deleterious effect of sleep deprivation on episodic memory consolidation. Therefore, lack of sleep severely impairs the consolidation of both emotional and neutral memories, as valence-related effects on memory consolidation were not observed after sleep deprivation.