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Jiřı́ Horáček

Charles University, National Institute of Mental Health

26 papers in the library · 936 citations · publishing 2007-2026

Papers

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Psilocybin-induced changes in electroencephalography link acute and long-term effects

Journal of Psychopharmacology September 4, 2026 M. Nikolič, Tom Froese, Pedro A. M. Mediano et al.

Background: Psilocybin’s therapeutic potential is neurophysiologically characterized by acute alpha power reductions and increased entropy. However, the systematic time-course of these changes from administration through the 24-hour sub-acute phase remains poorly characterized. Methods: In a double-blind, placebo-controlled, crossover trial ( N = 20, 10 females), healthy participants received a...

EEG microstate dynamics during psilocybin intoxication relate to acute experience and persisting psychological changes

bioRxiv (Cold Spring Harbor Laboratory) June 12, 2026 Nikola Jajcay, Čestmír Vejmola, Jakub Korčák et al.

Abstract Psilocybin and other serotonergic psychedelics show therapeutic promise for psychiatric disorders, yet objective neural correlates linking the acute psychedelic state to persisting psychological outcomes remain limited. Electroencephalography (EEG) microstate analysis characterizes the rapid spatiotemporal organization of large-scale brain activity, offering a millisecond-resolution...

The effects of psilocybin on time perception in humans: A comparative analysis of subjective and objective measures

Journal of Psychopharmacology 2026 Petr Scholle, Štěpán Wenke, Tereza Nekovářová et al. 1 citation

Background: Although psychedelics have regained attention as potential treatment tools for various mental disorders, little research has examined their impact on temporal perception. Aims: This double-blinded placebo-controlled study aimed to investigate changes in temporal perception under psilocybin, both through performance during the Temporal Bisection Task (TBT) and through subjective...

Regional specificity of the cingulate cortex thickness association with the intensity of psilocybin experience: a replication study

Psychopharmacology December 13, 2025 David Greguš, Jaroslav Hlinka, Filip Tylš et al.

Individual variability in psilocybin response is a major challenge for psychedelic-assisted therapy, with structural brain features potentially serving as predictive biomarkers. (Lewis et al. Biomedicines 8(2):34 2020) reported that rostral anterior cingulate cortex thickness predicted emotional experiences under psilocybin, suggesting cortical morphometry as a marker of psychedelic...

Regional Specificity of the Cingulate Cortex Thickness Association with the Intensity of Psilocybin Experience: A Replication Study

Research Square September 25, 2025 David Greguš, Jaroslav Hlinka, Filip Tylš et al.

Abstract Rationale: Individual variability in psilocybin response is a major challenge for psychedelic-assisted therapy, with structural brain features potentially serving as predictive biomarkers. Lewis et al. (2020) reported that rostral anterior cingulate cortex thickness predicted emotional experiences under psilocybin, suggesting cortical morphometry as a marker of psychedelic...

What fMRI studies say about the nature of the psychedelic effect: a scoping review

Frontiers in Neuroscience July 1, 2025 Michal Beneš, Tomáš Páleníček, Jiřı́ Horáček 4 citations

Research on psychedelic drugs, such as psilocybin, LSD or DMT, is a burgeoning field, with an increasing number of studies showing their promise in treatment of mental disorders as well as examining their mechanism of action. Determining their effect on the brain is crucial from clinical standpoint, but also offers highly promising avenues of advancement in basic neuroscience—functional...

Effects of Clozapine, Haloperidol, and the NMDA Antagonist Ketamine on Novel Object Recognition in Gnathonemus petersii: A New Possible Model for Schizophrenia Research

Fishes May 15, 2025 Petra Horká, Josefina Mavrogeni, Veronika Langová et al. 1 citation

In animal models, ketamine, a non-competitive N-methyl-D-aspartate (NMDA) antagonist, induces schizophrenia-like symptoms, such as positive and negative symptoms, as well as cognitive deficits. In the present study, we evaluated the behavioral responses and the number of EODs (electric organ discharges) of the weakly electric fish Gnathonemus petersii using the novel object recognition task...

Underlying pharmacological mechanisms of psilocin-induced broadband desynchronization and disconnection of EEG in rats

Frontiers in Neuroscience June 22, 2023 Filip Tylš, Čestmír Vejmola, Vlastimil Koudelka et al. 9 citations

Introduction Psilocybin is one of the most extensively studied psychedelic drugs with a broad therapeutic potential. Despite the fact that its psychoactivity is mainly attributed to the agonism at 5-HT 2A receptors, it has high binding affinity also to 5-HT 2C and 5-HT 1A receptors and indirectly modulates the dopaminergic system. Psilocybin and its active metabolite psilocin, as well as other...

Ketamine disrupts locomotion and electrolocation in a novel model of schizophrenia, Gnathonemus petersii fish

Journal of Neuroscience Research March 3, 2023 Veronika Langová, Petra Horká, Jan Hubený et al. 10 citations

The present study aimed to examine a weakly electric fish Gnathonemus petersii (G. petersii) as a candidate model organism of glutamatergic theory of schizophrenia. The idea of G. petersii elevating the modeling of schizophrenia symptoms is based on the fish's electrolocation and electrocommunication abilities. Fish were exposed to the NMDA antagonist ketamine in two distinct series differing...

Psilocybin—Mediated Attenuation of Gamma Band Auditory Steady-State Responses (ASSR) Is Driven by the Intensity of Cognitive and Emotional Domains of Psychedelic Experience

Journal of Personalized Medicine June 19, 2022 Vojtěch Viktorin, Inga Griškova-bulanova, Aleksandras Voicikas et al. 19 citations

Psilocybin is a classical serotoninergic psychedelic that induces cognitive disruptions similar to psychosis. Gamma activity is affected in psychosis and is tightly related to cognitive processing. The 40 Hz auditory steady-state responses (ASSR) are frequently used as indicators to test the ability to generate gamma activity. Based on previous literature, we studied the impact of psilocybin on...

Does Psychedelic Therapy Have a Transdiagnostic Action and Prophylactic Potential?

Frontiers in Psychiatry July 19, 2021 Rita Kočárová, Jiřı́ Horáček, Robin Carhart-Harris 95 citations

Addressing global mental health is a major 21st-century challenge. Current treatments have recognized limitations; in this context, new ones that are prophylactic and effective across diagnostic boundaries would represent a major advance. The view that there exists a core of transdiagnostic overlap between psychiatric disorders has re-emerged in recent years, and evidence that psychedelic...

Predictive value of heart rate in treatment of major depression with ketamine in two controlled trials

Clinical Neurophysiology March 14, 2021 Torsten M. Meyer, Martin Brunovský, Jiřı́ Horáček et al. 25 citations

OBJECTIVE: Ketamine has been shown to be effective in treatment of episodes of major depressive disorder (MDD). This controlled study aimed to analyse the predictive and discriminative power of heart rate (HR) and heart rate variability (HRV) for ketamine treatment in MDD. METHODS: In 51 patients, HR and HRV were assessed at baseline before and during ketamine infusion and 24 hours post...

The Effects of Daytime Psilocybin Administration on Sleep: Implications for Antidepressant Action

Frontiers in Pharmacology December 3, 2020 Daniela Dudysová, Karolína Janků, Michal Šmotek et al. 37 citations

Serotonergic agonist psilocybin is a psychedelic with antidepressant potential. Sleep may interact with psilocybin’s antidepressant properties like other antidepressant drugs via induction of neuroplasticity. The main aim of the study was to evaluate the effect of psilocybin on sleep architecture on the night after psilocybin administration. Regarding the potential antidepressant properties, we...

The Antidepressant Effect of Ketamine Is Dampened by Concomitant Benzodiazepine Medication

Frontiers in Psychiatry August 28, 2020 Veronika Andrashko, Tomáš Novák, Martin Brunovský et al. 46 citations

The rapid antidepressant effect of ketamine has become a breakthrough in the research and treatment of depression. Although predictive and modulating factors of the response to ketamine are broadly studied, little is known about optimal concurrent medication protocols. Concerning gamma-aminobutyric acid neurotransmission being a shared target for both ketamine and benzodiazepines (BZD), we...

Cannabis-induced altered states of consciousness are associated with specific dynamic brain connectivity states

Journal of Psychopharmacology June 3, 2019 Yuliya Zaytseva, Jiřı́ Horáček, Jaroslav Hlinka et al. 25 citations

BACKGROUND: Cannabis, and specifically one of its active compounds delta-9-tetrahydrocannabinol in recreational doses, has a variety of effects on cognitive processes. Most studies employ resting state functional magnetic resonance imaging techniques to assess the stationary effects of cannabis and to-date one report addressed the impact of delta-9-tetrahydrocannabinol on the dynamics of...

Intrinsic Rivalry. Can White Bears Help Us With the Other Side of Consciousness?

Frontiers in Psychology May 10, 2019 Marek Havlík, Eva Kozáková, Jiřı́ Horáček 4 citations

Studies of consciousness have traditionally been based mainly upon the perceptual domains of consciousness. However, there is another side of consciousness, represented by various types of intrinsic conscious experiences. Even though intrinsic experiences can represent up to 50 percent of our conscious experiences, they are still largely neglected in conscious studies. We assume there are two...

Do Personality Features Influence Our Intuitions of the Mind-Body Problem? A Pilot Study

Frontiers in Psychology July 20, 2018 Marek Havlík, Karolína Mladá, Iveta Fajnerová et al. 3 citations

The elusive relationship between the mental domain and the physical brain, known as the mind-body problem, is still a hot topic of discussion among philosophers and neuroscientists. Rather than solving this problem, our pilot study addresses the question as to whether personality features could influence intuitions of the mind-body problem, or more precisely, whether it is possible to identify...

Psilocybin disrupts sensory and higher order cognitive processing but not pre-attentive cognitive processing—study on P300 and mismatch negativity in healthy volunteers

Psychopharmacology January 5, 2018 Anna Bravermanová, Michaela Viktorinová, Filip Tylš et al. 50 citations

RationaleDisruption of auditory event-related evoked potentials (ERPs) P300 and mismatch negativity (MMN), electrophysiological markers of attentive and pre-attentive cognitive processing, is repeatedly described in psychosis and schizophrenia. Similar findings were observed in a glutamatergic model of psychosis, but the role of serotonergic 5-HT2A receptors in information processing is less...

PM506. Psilocybin Clinical Trial: Acute Effects and its relationship to the brain activity as measured by quantitative EEG

The International Journal of Neuropsychopharmacology May 27, 2016 Filip Tylš, Michaela Viktorinová, Dominika Prokopcova et al. 10 citations

Objective: Schizophrenia patients have a higher prevalence of type 2 diabetes mellitus than the general population, and even first-episode, drug-naive (FEDN) patients with schizophrenia have shown a higher prevalence of impaired glucose tolerance (IGT) than the general population.We aimed to investigate the prevalence of abnormal glucose tolerance after glucose loading, and to examine the...

Altered Neural Correlate of the Self-Agency Experience in First-Episode Schizophrenia-Spectrum Patients: An fMRI Study

Schizophrenia Bulletin December 18, 2015 Filip Španiel, Jaroslav Tintěra, Jan Rydlo et al. 55 citations

BACKGROUND: The phenomenology of the clinical symptoms indicates that disturbance of the sense of self be a core marker of schizophrenia. AIMS: To compare neural activity related to the self/other-agency judgment in patients with first-episode schizophrenia-spectrum disorders (FES, n = 35) and healthy controls (HC, n = 35). METHOD: A functional magnetic resonance imaging (fMRI) using motor task...

Sex differences and serotonergic mechanisms in the behavioural effects of psilocin

Behavioural Pharmacology October 13, 2015 Filip Tylš, Tomáš Páleníček, L. Kadeřábek et al. 86 citations

Psilocybin has recently attracted a great deal of attention as a clinical research and therapeutic tool. The aim of this paper is to bridge two major knowledge gaps regarding its behavioural pharmacology – sex differences and the underlying receptor mechanisms. We used psilocin (0.25, 1 and 4 mg/kg), an active metabolite of psilocybin, in two behavioural paradigms – the open-field test and...

Anti-correlated Brain Networks and Self-agency Experience in First-episode Schizophrenia-spectrum Patients. an FMRI Study.

European Psychiatry March 1, 2015 Filip Španiel, Jaroslav Tintěra, Jan Rydlo et al. 1 citation

In this study we sought to explore patterns of neural activity related to the self/other-agency judgment in patients with first-episode schizophrenia spectrum disorders (FES) and healthy controls (HC). Thirty-five FES patients and 35 age-, gender- and education-matched healthy controls. A task-related functional connectivity analysis with the use of independent component analysis (ICA). ICA...

Psilocybin – Summary of knowledge and new perspectives

European Neuropsychopharmacology December 17, 2013 Filip Tylš, Tomáš Páleníček, Jiřı́ Horáček 267 citations

Psilocybin, a psychoactive alkaloid contained in hallucinogenic mushrooms, is nowadays given a lot of attention in the scientific community as a research tool for modeling psychosis as well as due to its potential therapeutic effects. However, it is also a very popular and frequently abused natural hallucinogen. This review summarizes all the past and recent knowledge on psilocybin. It briefly...

Electroencephalographic Spectral and Coherence Analysis of Ketamine in Rats: Correlation with Behavioral Effects and Pharmacokinetics

Neuropsychobiology 2011 Tomáš Páleníček, Michaela Fujáková, Martin Brunovský et al. 85 citations

AIMS: This study was designed to evaluate the changes in EEG power spectra and EEG coherence in a ketamine model of psychosis in rats. Analyses of behavioral measurements--locomotion and sensorimotor gating--and the pharmacokinetics of ketamine and norketamine were also conducted. METHODS: Ketamine and norketamine levels in rat sera and brains were analyzed by gas chromatography-mass...

Subanesthetic dose of ketamine decreases prefrontal theta cordance in healthy volunteers: implications for antidepressant effect

Psychological Medicine December 9, 2009 Jiřı́ Horáček, Martin Brunovský, Tomáš Novák et al. 42 citations

BACKGROUND: Theta cordance is a novel quantitative electroencephalography (QEEG) measure that correlates with cerebral perfusion. A series of clinical studies has demonstrated that the prefrontal theta cordance value decreases after 1 week of treatment in responders to antidepressants and that this effect precedes clinical improvement. Ketamine, a non-competitive antagonist of...