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Gary F. Egan

12 papers in the library · 224 citations · publishing 1999-2025

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...

Correction: Neural mechanisms of psychedelic visual imagery.

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

In the sentence beginning ‘Connectivity from the EVA follows two broad pathways. The dorsal pathway is connected with the fusiform gyrus (FG), which is part of the inferior temporal cortex that functions to recognise objects and faces [45]. The ventral pathway from the EVA is connected to the intraparietal sulcus (IPS), which, along with the inferior frontal gyrus (IFG), is involved 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...

DOI: 10.1101/2025.03.09.642197 (opens in new tab) Full text (opens in new tab) Psilocybin Consciousness Context archaeology Cognitive psychology +6

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...

DOI: 10.1016/j.biopsych.2024.01.002 (opens in new tab) Psilocybin Amygdala Cognition Resting State FMRI +3

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...

DOI: 10.1016/j.biopsych.2022.07.013 (opens in new tab) Full text (opens in new tab) Ego dissolution Anticorrelated networks Dynamic causal modeling Effective connectivity +8

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...

DOI: 10.3389/fnins.2022.827400 (opens in new tab) Ego dissolution Belief updating Hierarchical predictive coding Precision +1

The role of primordial emotions in the evolutionary origin of consciousness.

Consciousness and Cognition June 2009 Derek Denton, Michael McKinley, M Farrell et al.

Primordial emotions are the subjective element of the instincts which are the genetically programmed behaviour patterns which contrive homeostasis. They include thirst, hunger for air, hunger for food, pain and hunger for specific minerals etc. There are two constituents of a primordial emotion--the specific sensation which when severe may be imperious, and the compelling intention for...

Neural correlates of the emergence of consciousness of thirst.

Proceedings of the National Academy of Sciences 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....

Neuroimaging of genesis and satiation of thirst and an interoceptor-driven theory of origins of primary consciousness.

Proceedings of the National Academy of Sciences of the United States of America April 1, 1999 Derek Denton, Robert Shade, F Zamarippa et al.

There are defined hypothalamic functions in the genesis of thirst, but little is known of the cortical processes subserving consciousness of thirst notwithstanding the medical disorders that occur in psychiatric illness, addiction, and the attested decline of thirst with aging. In 10 adult males, positron emission tomography scans were made (i) during genesis of moderate thirst by infusion of...

DOI: 10.1073/pnas.96.9.5304 (opens in new tab) Full text (opens in new tab) Brain Animals Humans Saline solution, hypertonic +6

Resting state functional coupling between the ascending synchronising system, limbic system and the default mode network via theta oscillations

Parnesh Raniga, Bryan Paton, Gary F. Egan preprint

Abstract: In order to better understand dysfunction in dementia and psychiatric illnesses, the underlying neuronal systems that give rise to normal memory and cognitive processes need to be better understood. Based on electrophysiological recordings in animals, theta oscillations have been proposed as an intrinsic mechanism for the orchestration of memory functions, especially episodic and...