In drug-free adults with narcolepsy type 1, successful dream recall after naps is linked to a more activated brain state during both REM and NREM sleep. Using scalp EEG, the study found that recall was associated with lower delta power over centro-parietal areas in both sleep stages, higher beta power in those areas during NREM, and a lower delta/beta ratio across most scalp locations during NREM. These results suggest that a more desynchronized, activated electrophysiological milieu promotes dream recall, and that parietal areas are important not only for generating dream experiences but also for the memory processes that enable recall.
Dream recall upon awakening from NREM sleep is predicted by reduced delta activity in left frontal and temporo-parietal areas during the final segment of sleep. This finding suggests that increased cortical activation is a prerequisite for remembering dreams from NREM sleep, challenging the traditional view that dreaming is unique to REM sleep. The study used a multiple nap protocol and within-subjects design to collect dream reports after stage 2 NREM sleep awakenings. The results indicate that the brain mechanisms underlying dream recall during NREM sleep may share features with those involved in encoding episodic memories during wakefulness, though they also depend on the specific electrophysiological state of sleep.