TMS-EEG and resting-state EEG applied to altered states of consciousness: oscillations, complexity, and phenomenology.
iScience – May 19, 2023
Source: PubMed
Summary
Clinical neuroscience reveals fascinating insights into how psychedelic compounds affect brain activity. Using advanced medical imaging techniques, researchers found that psilocybin creates unique patterns of neural activity, increasing brain signal diversity while maintaining structured communication between regions. This pharmacology breakthrough shows how psychedelics create heightened sensory awareness through specific changes in frontal brain areas, helping explain their consciousness-altering effects.
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.