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.
Sci Rep
October 16, 2024
Andreas Krabbe, Pilleriin Sikka, Jussi Jylkkä
9 citations
Psychological flexibility—the ability to adapt thoughts and behaviors to changing circumstances—may explain why psychedelic experiences can improve mental well-being. In a cross-sectional internet survey of 629 people who had used classical psychedelics, network analysis showed that the depth of psychological insight during a single psychedelic experience, rather than how often someone had used psychedelics, was linked to the psychological flexibility component of Acceptance. Mediation analyses indicated that psychological flexibility mediated the relationship between past psychedelic use and both well-being and ill-being. The findings suggest that the quality of the psychedelic experience, especially fostering acceptance, is more important than frequency of use for long-term mental health benefits.
Conscious Cogn
July 7, 2025
Jussi Jylkkä, Hilla Väyrynen, Enyu Lin et al.
3 citations
Meditation and psychedelics both foster mystical, psychological, and philosophical-existential insights that predict wellbeing. A qualitative-quantitative study found that these insights, whether from meditation or controlled psychedelic use, are associated with positive shifts in personal wellbeing. The authors suggest that the types of insights from both practices overlap and can profoundly benefit individuals, leading to enhanced wellbeing and personal transformation.
JAMA psychiatry
June 1, 2026
Ben Deverett, Duan Li, Theresa R Lii et al.
1 citation
Ketamine produces distinct brain-wave patterns that may be linked to its therapeutic effects. General anesthesia selectively blocks one of these patterns—theta oscillations—while leaving another pattern, beta-gamma oscillations, intact. In 52 participants, ketamine given during anesthesia preserved beta-gamma power increases but eliminated the characteristic theta augmentation seen during awake administration. This suggests that different neurophysiologic effects of ketamine can be separated, offering a way to investigate which brain-wave changes underlie its antidepressant, analgesic, or dissociative properties.
Consciousness and Cognition
December 15, 2025
Andreas Krabbe, Pilleriin Sikka, Jussi Jylkkä
Meditation practice may enhance the benefits of psychedelic experiences and can confound associations between psychedelic use and well-being. In two cross-sectional online surveys, when examined separately, both cumulative psychedelic use and meditation practice were associated with greater well-being and psychological flexibility. However, when considered jointly, the associations for psychedelics were reduced or became nonsignificant, while meditation remained consistently associated with outcomes. In a second study, participants who experienced a personally meaningful event through meditation alone or combined with psychedelics reported significantly greater improvements in well-being compared with those who used psychedelics alone, though all groups showed positive change on average. Weak evidence suggested a potential synergy between the two practices.
medRxiv
August 7, 2025
Ben Deverett, Duan Li, Theresa R. Lii et al.
preprint
Ketamine produces dissociative, analgesic, and antidepressant effects, but it is unclear whether its underlying neurophysiological signatures can be separated. In this observational cohort study, 52 participants (healthy volunteers, elective surgery patients, and patients with depression) received a subanesthetic infusion of ketamine or placebo, with or without general anesthesia. When ketamine was given under general anesthesia, its characteristic low-frequency brain wave augmentation was absent, while high-frequency power modulation was preserved. This selective modulation suggests a method for investigating the distinct roles of high- and low-frequency neural activity in ketamine's behavioral effects.
British journal of anaesthesia
August 1, 2026
Pilleriin Sikka, Sherry Hu, Boris D Heifets
Dreaming during anaesthesia is common and has been documented for over a century, but remains poorly understood. This review of 157 studies from 1921 to 2024 involving 87,866 participants found that dream recall rates vary widely, from 3% to 8% in large clinical trials to 40% to 80% in experimental settings. Ketamine and propofol are most consistently associated with recall. Dreams are predominantly pleasant and feature everyday autobiographical content. Dream recall is not linked to intraoperative awareness, challenging the idea that dreams indicate inadequate anaesthetic depth. Higher home dream recall, preoperative suggestion, and immediate post-emergence assessment increase recall rates. Unpleasant dreams reduce willingness to undergo the same anaesthetic again. The positive nature and suggestibility of anaesthesia dreams suggest potential therapeutic uses.