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 via PubMed
Summary
AI-generated from the abstractClassical psychedelic drugs like psilocybin induce profound changes in consciousness, including heightened sensory-emotional awareness and arousal, accompanied by increased spontaneous EEG signal diversity. By combining Transcranial Magnetic Stimulation (TMS) with EEG, this work shows that psilocybin creates a state of increased chaotic brain activity, which is not due to altered complexity in causal interactions between brain regions. The study also maps regional effects of psilocybin on TMS-evoked activity, identifying changes in frontal brain structures that may relate to the phenomenology of psychedelic experiences.
Study at a glance
| Characteristics | Experimental study Peer reviewed |
|---|---|
| Intervention | Psilocybin |
| Topics | Psilocybin |
| Keywords | Medical imaging Pharmacology Neuroscience clinical neuroscience Brain science Neural studies |
| Citations | 47 |
| Key finding | 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.