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Effects of psychedelics on human oscillatory brain activity
Kate Godfrey1, Lisa X Luan1, Christopher Timmermann1
1Division of Psychiatry, Department of Brain Sciences, Centres for Neuropsychopharmacology & Psychedelic Research, Imperial College London, London, United Kingdom.
International Review of Neurobiology
|June 20, 2025
Summary
Classic psychedelics like LSD and psilocybin reduce alpha brain waves and increase neural complexity. Real-time subjective intensity correlates with these objective electroencephalography (EEG) changes, suggesting potential biomarkers.
Area of Science:
- Neuroscience
- Psychopharmacology
Background:
- Classic psychedelics induce profound alterations in consciousness.
- Understanding their neurophysiological underpinnings is crucial for therapeutic applications.
Purpose of the Study:
- To review the effects of classic psychedelics on human brain activity.
- To explore the relationship between subjective experience and objective neural measures.
Main Methods:
- Analysis of resting-state electroencephalography (EEG) and magnetoencephalography (MEG) data.
- Measurement of spectral power, signal diversity (e.g., Lempel-Ziv complexity), and functional connectivity.
- Correlation with real-time subjective intensity and plasma drug levels.
Main Results:
- Consistent reduction in alpha power (8-13 Hz) across multiple psychedelics (LSD, psilocybin, ayahuasca, DMT).
- Increased signal diversity indicating more variable neural firing patterns.
- Real-time subjective intensity robustly covaries with EEG spectral power and complexity.
Conclusions:
- Psychedelic drug activity can be objectively measured through EEG biomarkers.
- Altered brain dynamics, including reduced top-down control, may underlie psychedelic experiences.
- Future research should integrate unified methods and high-resolution behavioral sampling for clinical translation.
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