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Pilleriin Sikka

Stanford University

4 papers in the library · 11 citations · publishing 2025-2026

Papers

A dream EEG and mentation database.

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.

General Anesthesia and Discrete Components of Ketamine Neurophysiology.

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.

The interplay of psychedelic use and meditation in shaping psychological well-being

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.

General anesthesia dissociates discrete components of ketamine neurophysiology

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.