The electroencephalographic changes in animal serotonergic model of psychosis-the study of EEG connectivity in relation to behavior

The present thesis deals with the electrophysiological and behavioral correlates of the effects of serotonergic psychedelics in an animal model of psychosis. In the general part, we describe the phenomenology and neurobiology of psychotic diseases and the altered states of consciousness induced by serotonergic psychedelics. Furthermore, we outline the pharmacological models of acute psychosis with a focus on serotonergic substances, particularly the active substances from hallucinogenic mushroom - the indolamine psilocybin and its active metabolite psilocin. We briefly explain the method of quantitative electroencephalography (QEEG) and summarize the main findings of QEEG in animals and humans intoxicated by serotonergic psychedelics. The experimental part of the thesis describes the pharmacokinetics of psilocin, its effects on the behavioral pattern, locomotion and sensorimotor processing of information, as well as sex differences in the behavioral response. A medium dose of psilocin caused atypical behavioral figures, decreased locomotion and disturbance in sensorimotor processing of information, with the females being more resistant to this effect. Another focus of the thesis is the dynamics of QEEG changes in time (EEG absolute power spectra and EEG coherences), as recorded from the cortex of...SOUHRN Předkládaná práce se zabývá elektrofyziologickými a behaviorálními koreláty účinku serotonergních psychedelik v rámci animálního modelu psychózy. V obecné části je popsána fenomenologie a neurobiologie psychotických onemocnění a změněných stavů vědomí způsobených intoxikací serotonergními psychedeliky. Dále se práce věnuje přehledu farmakologických modelů akutní psychózy se zaměřením na serotonergní látky, zejména pak aktivní látky z halucinogenních hub - indolamin psilocybin a jeho aktivní metabolit psilocin. Ve stručnosti je přiblížena je metoda kvantitativní elektrofyziologie (QEEG) a shrnuty hlavní nálezy v QEEG u zvířat i lidí způsobených intoxikací serotonergními psycheliky. Vlastní experimentální část práce popisuje farmakokinetiku psilocinu, jeho vliv na behaviorální vzorec, lokomoci a senzorimotorické zpracování informace a také pohlavní rozdíly v behaviorální odpovědi. Psilocin vedl k atypickým behaviorálním figurám, snížení lokomoce a narušení sezorimotorického zpracování informace ve střední dávce, přičemž samice byli k těmto účinkům rezistentnější. Dále se zaměřuje na dynamiku QEEG změn v čase (EEG absolutní výkonová spektra a EEG koherence) snímané z kůry mozku volně se pohybujícího laboratorního potkana v průběhu behaviorální inaktivity vyvolané intoxikací psilocinem a dalšími...Department of Psychiatry and Medical Psychology - Department of PsychiatryKlinika psychiatrie a lékařské psychologie - klinika psychiatrie3. lékařská fakultaThird Faculty of Medicin

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

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 hypothesized that psilocybin, similar to other classical antidepressants, would reduce rapid eye movement (REM) sleep and prolong REM sleep latency. Moreover, we also hypothesized that psilocybin would promote slow-wave activity (SWA) expression in the first sleep cycle, a marker of sleep-related neuroplasticity. Twenty healthy volunteers (10 women, age 28–53) underwent two drug administration sessions, psilocybin or placebo, in a randomized, double-blinded design. Changes in sleep macrostructure, SWA during the first sleep cycle, whole night EEG spectral power across frequencies in non-rapid eye movement (NREM) and REM sleep, and changes in subjective sleep measures were analyzed. The results revealed prolonged REM sleep latency after psilocybin administration and a trend toward a decrease in overall REM sleep duration. No changes in NREM sleep were observed. Psilocybin did not affect EEG power spectra in NREM or REM sleep when examined across the whole night. However, psilocybin suppressed SWA in the first sleep cycle. No evidence was found for sleep-related neuroplasticity, however, a different dosage, timing, effect on homeostatic regulation of sleep, or other mechanisms related to antidepressant effects may play a role. Overall, this study suggests that potential antidepressant properties of psilocybin might be related to changes in sleep

The electroencephalographic changes in animal serotonergic model of psychosis-the study of EEG connectivity in relation to behavior

The present thesis deals with the electrophysiological and behavioral correlates of the effects of serotonergic psychedelics in an animal model of psychosis. In the general part, we describe the phenomenology and neurobiology of psychotic diseases and the altered states of consciousness induced by serotonergic psychedelics. Furthermore, we outline the pharmacological models of acute psychosis with a focus on serotonergic substances, particularly the active substances from hallucinogenic mushroom - the indolamine psilocybin and its active metabolite psilocin. We briefly explain the method of quantitative electroencephalography (QEEG) and summarize the main findings of QEEG in animals and humans intoxicated by serotonergic psychedelics. The experimental part of the thesis describes the pharmacokinetics of psilocin, its effects on the behavioral pattern, locomotion and sensorimotor processing of information, as well as sex differences in the behavioral response. A medium dose of psilocin caused atypical behavioral figures, decreased locomotion and disturbance in sensorimotor processing of information, with the females being more resistant to this effect. Another focus of the thesis is the dynamics of QEEG changes in time (EEG absolute power spectra and EEG coherences), as recorded from the cortex of..

What are the effects of chamber REST on the scientific understanding of reality? An exploratory study

In this paper we present an exploratory study on the understanding of reality among scientists. The nature of reality has been a conundrum for generations of theologians, philosophers, and scientists as well as the lay public. It also appears as a scientific problem in various disciplines, from physics to psychiatry and neuroscience. For the purpose of our study, we employed Chamber REST (Restricted Environmental Stimulation), which has been known to produce substantial perceptual effects such as visual or auditory pseudo-hallucinations. We hypothesized that such experiences could alter basic underlying metaphysical beliefs which our subject-scientists hold about reality. We conclude that the technique showed the potential to induce such changes, but the outcome is also probably dependent on their pre-existing views gained through previous experi-ences, such as for example altered states of consciousness. Also, the effects of Chamber REST seem to be in this respect comparable to psychedelic sessions

Psilocybin - mediated attenuation of gamma band auditory steady-state responses (ASSR) is driven by the intensity of cognitive and emotional domains of psychedelic experience

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 40 Hz ASSR in healthy volunteers. The study was double blind and placebo controlled with a crossover design. A sample of 20 healthy subjects (10M/10F) received psilocybin orally 0.26 mg/kg or placebo. Participants were measured four times in total, one time before ingestion of psilocybin/placebo and one time after ingestion, during the peak of intoxication. A series of 500 ms click trains were used for stimulation. Psilocybin induced a psychedelic effect and decreased 40 Hz ASSR phase-locking index compared to placebo. The extent of the attenuation was related to Cognition and Affect on the Hallucinogen Rating Scale. The current study shows that psilocybin lowers the synchronization level and the amplitude of 40 Hz auditory steady-state responses, which yields further support for the role of gamma oscillations in cognitive processing and its disturbance

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

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 hypothesized that psilocybin, similar to other classical antidepressants, would reduce rapid eye movement (REM) sleep and prolong REM sleep latency. Moreover, we also hypothesized that psilocybin would promote slow-wave activity (SWA) expression in the first sleep cycle, a marker of sleep-related neuroplasticity. Twenty healthy volunteers (10 women, age 28-53) underwent two drug administration sessions, psilocybin or placebo, in a randomized, double-blinded design. Changes in sleep macrostructure, SWA during the first sleep cycle, whole night EEG spectral power across frequencies in non-rapid eye movement (NREM) and REM sleep, and changes in subjective sleep measures were analyzed. The results revealed prolonged REM sleep latency after psilocybin administration and a trend toward a decrease in overall REM sleep duration. No changes in NREM sleep were observed. Psilocybin did not affect EEG power spectra in NREM or REM sleep when examined across the whole night. However, psilocybin suppressed SWA in the first sleep cycle. No evidence was found for sleep-related neuroplasticity, however, a different dosage, timing, effect on homeostatic regulation of sleep, or other mechanisms related to antidepressant effects may play a role. Overall, this study suggests that potential antidepressant properties of psilocybin might be related to changes in sleep