Nature Communications
August 13, 2025
William Wong, Rubén Herzog, Kátia Cristine Andrade et al.
10 citations
A new open database, the DREAM database, combines standardized sleep magneto/electroencephalography (M/EEG) recordings with dream reports from 505 participants across 20 datasets, totaling 2,643 awakenings. Each awakening includes at least 20 seconds of high-resolution sleep EEG (≥100 Hz, ≥2 electrodes) and a classification of the sleeper's reported experience. Analyses showed that reports of conscious experiences during sleep can be predicted from objective EEG features in both REM and NREM sleep. The database aims to overcome limitations of small sample sizes and methodological variability in dream research, enabling larger-scale investigations of the neurocognitive basis of dreaming.
bioRxiv (Cold Spring Harbor Laboratory)
June 28, 2025
Jessica Palmieri, Valentina Elce, Monika Schönauer
1 citation
preprint
Emotional intensity in dreams increases as the night progresses, with late-night dreams rated as more emotional than those from early sleep. This pattern was observed in a multiple awakening study of 20 participants who provided 61 dream reports. Contrary to expectations, the rise in emotionality was not tied to REM sleep awakenings. Late-night dream reports were also longer, but report length did not correlate with emotional intensity, suggesting that emotionality is independent of recall ability or narrative complexity. The findings indicate that emotional processing during sleep may unfold across the night through mechanisms separate from those governing dream recall or story elaboration.
Sleep
September 18, 2025
Jessica Palmieri, Deniz Kumral, Sammy-Jo Wymer et al.
Dreams incorporate specific information from waking experiences, and this incorporation may aid memory consolidation. Participants listened to an audiobook while falling asleep and were awakened during the night to report dreams. Blind raters could identify which audiobook a participant had heard based solely on dream reports, for both NREM and REM sleep dreams. Participants whose dreams more strongly incorporated the audiobook content tended to recognize more of that content later. The findings suggest that salient daytime experiences resurface in dreams and that content selected for memory consolidation during sleep is more strongly incorporated into dreams.
Deniz Kumral, Jessica Palmieri, Steffen Gais et al.
preprint
Dreams incorporate recent experiences, and memory-related brain activity is reactivated during sleep, suggesting a tight link between dreaming, memory consolidation, and reactivation. In this study, participants listened to different audiobooks before falling asleep. Brain activity during rapid eye movement (REM) sleep, particularly in the beta range, carried information about the audiobook. Global beta power during REM sleep was associated with better memory performance, but the amount of neural reinstatement did not correlate with memory retention. Blind raters could determine which audiobook participants had studied based on dream reports. Participants who dreamt of the audiobook showed stronger neural reinstatement. Reprocessing of pre-sleep experiences during sleep may thus shape brain activity, dreams, and memories.