May 16, 2023
William Wong, Kátia C. Andrade, Thomas Andrillon et al.
21 citations
preprint
A new open-access database, DREAM, combines sleep magneto/electroencephalography (M/EEG) recordings with standardized dream reports to enable large-scale neurocognitive research on dreaming. The initial release includes 20 datasets from 561 participants and 2649 awakenings, each with at least 20 seconds of high-frequency M/EEG data and a classification of the subject's experience. Analyses demonstrate that features extracted from EEG can predict whether a person reports having had a conscious experience during both REM and NREM sleep. The database aims to overcome the limitations of small sample sizes and methodological variability in dream research, allowing new questions to be addressed at a scale unattainable by individual labs.
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)
September 8, 2025
Adriana Michalak, Davide Marzoli, Francesco Pietrogiacomi et al.
preprint
Perceived sleep depth, a key factor in subjective sleep quality, is traditionally linked to unconsciousness and reduced brain activity. Using high-density EEG and a serial awakening paradigm during NREM sleep, researchers found that deeper sleep corresponded to lower high-to-low frequency power ratio, indicating reduced cortical activation. However, this relationship weakened when dreaming occurred, suggesting immersive conscious experiences can counteract the effect of cortical activation on perceived depth. Perceived sleep depth was lowest during states with a mere sense of presence and highest during immersive dreaming or deep unconsciousness. As the night progressed, physiological sleep pressure and subjective sleepiness declined, but perceived sleep depth increased alongside rising dream immersiveness. These findings challenge the view that deep sleep stems solely from reduced brain activity.
PLoS Biology
March 1, 2026
Adriana Michalak, Davide Marzoli, Francesco Pietrogiacomi et al.
Perceived sleep depth, a key part of subjective sleep quality, is traditionally linked to unconsciousness and reduced brain activity. Combining high-density EEG with a serial awakening paradigm during N2 sleep in healthy participants, the study found that deeper sleep was associated with a lower high-to-low frequency power ratio, indicating reduced cortical activation. However, this relationship weakened when dreaming occurred, suggesting immersive conscious experiences can counteract the impact of cortical activation on perceived depth. Perceived sleep depth was lowest during minimal awareness (a mere sense of presence) and highest during immersive dreaming or deep unconsciousness.
Communications Psychology
February 18, 2025
Valentina Elce, Damiana Bergamo, Giorgia Bontempi et al.
Dream recall varies widely between people and across nights. In 217 healthy adults aged 18 to 70, attitude toward dreaming, tendency to mind-wander, and sleep patterns were associated with whether a person reported a dream upon waking. The likelihood of recalling dream content was predicted by age and vulnerability to interference. Night-to-night changes in sleep patterns and seasonal fluctuations also influenced dream recall. These findings help explain why some people remember dreams more often than others and why recall varies within the same person.
Valentina Elce, Damiana Bergamo, Giorgia Bontempi et al.
preprint
Dream recall varies greatly between people and across nights. In a study of 204 healthy adults aged 18 to 70, attitude toward dreaming, tendency to mind-wander, and sleep patterns were associated with how likely someone was to report a dream upon waking. The probability of recalling specific dream content was predicted by age and vulnerability to interference. Dream recall also fluctuated with nightly changes in sleep patterns and showed seasonal variation. These findings help explain why dream recall differs both between individuals and within the same person over time.