TMS-EEG and resting-state EEG applied to altered states of consciousness: oscillations, complexity, and phenomenology.
Andres Ort, John W Smallridge, Simone Sarasso, Silvia Casarotto, Robin von Rotz, Andrea Casanova, Erich Seifritz, Katrin H. Preller, Giulio Tononi, Franz X. Vollenweider
iScience May 19, 2023 DOI: 10.1016/j.isci.2023.106589 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Experimental study Peer reviewed |
|---|---|
| Intervention | Psilocybin |
| Topics | Psilocybin Altered states of consciousness Philosophy of mind |
| Keywords | Medical imaging Pharmacology Neuroscience clinical neuroscience Brain science Neural studies Psychedelics hallucinogens Psychoactive compounds Neuroimaging Brain scanning |
| Citations | 47 |
| Key findings | Psilocybin produces a state of increased chaotic brain activity that is not a result of altered complexity in the underlying causal interactions between brain regions, and it evokes changes in frontal brain structures potentially linked to psychedelic experiences. |
Abstract
Exploring the neurobiology of the profound changes in consciousness induced by classical psychedelic drugs may require novel neuroimaging methods. Serotonergic psychedelic drugs such as psilocybin produce states of increased sensory-emotional awareness and arousal, accompanied by increased spontaneous electroencephalographic (EEG) signal diversity. By directly stimulating cortical tissue, the altered dynamics and propagation of the evoked EEG activity can reveal drug-induced changes in the overall brain state. We combine Transcranial Magnetic Stimulation (TMS) and EEG to reveal that psilocybin produces a state of increased chaotic brain activity which is not a result of altered complexity in the underlying causal interactions between brain regions. We also map the regional effects of psilocybin on TMS-evoked activity and identify changes in frontal brain structures that may be associated with the phenomenology of psychedelic experiences.
Comparable studies
Other experimental studies on altered states of consciousness, most cited first.
| Study | Year | Design | Participants |
|---|---|---|---|
| The Standardized Psychometric Assessment of Altered States of Consciousness (ASCs) in Humans Healthy subjects in six countries | 1998 | Experimental and field study | n = 1,133 |
| A Test of the Psychedelic Model of Altered States of Consciousness | 1976 | Experimental study with comparison groups | |
| Neural Correlates of Non-ordinary States of Consciousness in Pranayama Practitioners: The Role of Slow Nasal Breathing Experienced meditators | 2022 | Within-subjects comparison | n = 12 |
| Increased spontaneous EEG signal diversity during stroboscopically-induced altered states of consciousness Healthy adults | 2019 | Experimental study | |
| Cannabis-induced altered states of consciousness are associated with specific dynamic brain connectivity states Healthy occasional cannabis users (smoking cannabis ≤2 per week) | 2019 | Repeated-measures, within-subjects design | n = 19 |
Citations in the library
Cited by 33
- Neural complexity is increased after low doses of LSD, but not moderate to high doses of oral THC or methamphetamine. Neuropsychopharmacology June 1, 2024
- Psychedelics and disorders of consciousness: the current landscape and the path forward. Neuroscience of Consciousness June 15, 2024
- Paradoxical pharmacological dissociations result from drugs that enhance delta oscillations but preserve consciousness Communications Biology June 20, 2023
- Complex slow waves in the human brain under 5-MeO-DMT. Cell Reports July 22, 2025
- Psychedelics, entactogens and psychoplastogens for depression and related disorders British Journal of Pharmacology June 15, 2025
and 28 more in the library
Cites 37
- An information integration theory of consciousness BMC Neuroscience November 2, 2004
- A Theoretically Based Index of Consciousness Independent of Sensory Processing and Behavior Science Translational Medicine August 14, 2013
- Psilocybin induces schizophrenia-like psychosis in humans via a serotonin-2 agonist action Neuroreport December 1, 1998
- Neural correlates of the LSD experience revealed by multimodal neuroimaging. Proceedings of the National Academy of Sciences April 11, 2016
- Psychometric Evaluation of the Altered States of Consciousness Rating Scale (OAV) PLoS One August 31, 2010
and 32 more in the library