Psychopharmacology
January 5, 2018
Anna Bravermanová, Michaela Viktorinová, Filip Tylš et al.
50 citations
Psilocybin, a psychedelic that activates 5-HT2A receptors, disrupted early perceptual and higher-order cognitive processing in healthy volunteers but left pre-attentive cognition intact. In a double-blind, placebo-controlled crossover trial, 20 participants (10 men, 10 women) received 0.26 mg/kg of psilocybin orally. The drug produced robust psychedelic effects and psychotic-like symptoms, decreased the amplitude of the P300 event-related potential (a marker of attentive processing) and the N100 (an early perceptual marker), but did not affect mismatch negativity (MMN), a measure of pre-attentive processing. The disruption of P300 correlated with the intensity of the psychedelic state, which depended on psilocin serum levels. These findings suggest that 5-HT2A receptors play a role in altered information processing in psychosis and schizophrenia, particularly at early perceptual and higher-order cognitive levels.
Translational Psychiatry
October 2, 2021
Čestmír Vejmola, Filip Tylš, Václava Piorecká et al.
41 citations
Serotonergic psychedelics, including psilocin, LSD, mescaline, and DOB, all caused a time-dependent global decrease and desynchronization of EEG activity and functional disconnection in the 1–40 Hz range in freely moving rats, regardless of their chemical family. Major changes occurred in the frontal and sensorimotor cortex, with subtle spatial patterns unique to each substance. A rebound of occipital theta (4–8 Hz) activity appeared later after mescaline and LSD. Connectivity analyses revealed an overall decrease in global connectivity for both cross-spectral and phase-lagged coherence. These effects closely mirror those seen in human EEG/MEG studies, supporting the translational validity of this rodent model.
Frontiers in Neuroscience
June 22, 2023
Filip Tylš, Čestmír Vejmola, Vlastimil Koudelka et al.
9 citations
Psilocybin's psychoactivity is primarily attributed to agonism at 5-HT2A receptors, but it also binds to 5-HT2C and 5-HT1A receptors and indirectly modulates the dopaminergic system. In an animal model, psilocin (psilocybin's active metabolite) induced broadband desynchronization and disconnection in EEG, decreasing mean absolute power across 1–25 Hz and reducing global functional connectivity, particularly fronto-temporal connections. Antagonists of 5-HT1A, 5-HT2A, and 5-HT2C receptors, as well as antipsychotics haloperidol (D2 antagonist) and clozapine (mixed D2/5-HT antagonist), normalized power decreases in 1–25 Hz, but only clozapine affected 25–40 Hz decreases. The 5-HT2A antagonist reversed psilocin-induced connectivity decreases, while other drugs had no effect, indicating that multiple serotonergic and dopaminergic mechanisms contribute to these neurophysiological changes.