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Gary F. Egan

8 papers in the library · 224 citations · publishing 2003-2025

Papers

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Neural mechanisms of psychedelic visual imagery.

Molecular Psychiatry April 1, 2025 Devon Stoliker, Katrin H. Preller, Leonardo Novelli et al. 19 citations

Visual alterations under classic psychedelics can include rich phenomenological accounts of eyes-closed imagery. Preclinical evidence suggests agonism of the 5-HT2A receptor may reduce synaptic gain to produce psychedelic-induced imagery. However, this has not been investigated in humans. To infer the directed connectivity changes to visual connectivity underlying psychedelic visual imagery in...

Psychedelics Align Brain Activity with Context

bioRxiv (Cold Spring Harbor Laboratory) March 11, 2025 Devon Stoliker, Leonardo Novelli, Moein Khajehnejad et al. 8 citations preprint

Abstract Psychedelics can profoundly alter consciousness by reorganising brain connectivity; however, their effects are contextsensitive. To understand how this reorganisation depends on the context, we collected and comprehensively analysed the largest psychedelic neuroimaging dataset to date. Sixty-two adults were scanned with functional MRI and EEG during rest and naturalistic stimuli...

Neural Mechanisms of Resting-State Networks and the Amygdala Underlying the Cognitive and Emotional Effects of Psilocybin

Biological Psychiatry January 5, 2024 Devon Stoliker, Leonardo Novelli, Adeel Razi et al. 42 citations

Our findings suggest that temporary amygdala signal attenuation is associated with mechanistic changes to resting-state network connectivity. These changes are significant for altered cognition and perception and suggest targets for research investigating the efficacy of psychedelic therapy for internalizing psychiatric disorders. More broadly, our study suggests the value of quantifying the...

Effective Connectivity of Functionally Anticorrelated Networks Under Lysergic Acid Diethylamide.

Biological Psychiatry February 1, 2023 Devon Stoliker, Leonardo Novelli, Franz X. Vollenweider et al. 49 citations

Classic psychedelic-induced ego dissolution involves a shift in the sense of self and a blurring of the boundary between the self and the world. A similar phenomenon is identified in psychopathology and is associated with the balance of anticorrelated activity between the default mode network, which directs attention inward, and the salience network, which recruits the dorsal attention network...

Neural Mechanisms and Psychology of Psychedelic Ego Dissolution

Pharmacological Reviews September 9, 2022 Devon Stoliker, Adeel Razi, Gary F. Egan et al. 83 citations

Neuroimaging studies of psychedelics have advanced our understanding of hierarchical brain organization and the mechanisms underlying their subjective and therapeutic effects. The primary mechanism of action of classic psychedelics is binding to serotonergic 5-HT2A receptors. Agonist activity at these receptors leads to neuromodulatory changes in synaptic efficacy that can have a profound...

Effective connectivity of emotion and cognition under psilocybin

medRxiv September 9, 2022 Devon Stoliker, Leonardo Novelli, Franz X. Vollenweider et al. 4 citations preprint

Abstract Classic psychedelics alter sense of self and patterns of self-related thought. These changes are hypothesised to underlie their therapeutic efficacy across internalising pathologies such as addiction and depression. Using resting-state functional MRI images from a randomised, double blinded, placebo-controlled clinical trial of 24 healthy adults under 0.215mg/kg psilocybin, we...

Reduced Precision Underwrites Ego Dissolution and Therapeutic Outcomes Under Psychedelics

Frontiers in Neuroscience March 17, 2022 Devon Stoliker, Gary F. Egan, Adeel Razi 19 citations

Evidence suggests classic psychedelics reduce the precision of belief updating and enable access to a range of alternate hypotheses that underwrite how we make sense of the world. This process, in the higher cortices, has been postulated to explain the therapeutic efficacy of psychedelics for the treatment of internalizing disorders. We argue reduced precision also underpins change to...

Neural correlates of the emergence of consciousness of thirst.

Proceedings of the National Academy of Sciences of the United States of America December 9, 2003 Gary F. Egan, Tim Silk, Frank Zamarripa et al.

Thirst was induced by rapid i.v. infusion of hypertonic saline (0.51 M at 13.4 ml/min). Ten humans were neuroimaged by positron-emission tomography (PET) and four by functional MRI (fMRI). PET images were made 25 min after beginning infusion, when the sensation of thirst began to enter the stream of consciousness. The fMRI images were made when the maximum rate of increase of thirst occurred....