Neural mechanisms of psychedelic visual imagery

medRxiv (Cold Spring Harbor Laboratory), Journal Year: 2022, Volume and Issue: unknown

Published: Sept. 9, 2022

Abstract Visual alterations under classic psychedelics can include rich phenomenological accounts of eyes-closed imagery. Preclinical evidence suggests agonism the 5-HT2A receptor may reduce synaptic gain to produce psychedelic-induced However, this has not been investigated in humans. To infer directed connectivity changes visual sensory underlying psychedelic imagery healthy adults, a double-blind, randomised, placebo-controlled, cross-over study was performed, and dynamic causal modelling applied resting state functional MRI scans 24 subjects after administration 0.2mg/kg serotonergic drug, psilocybin (magic mushrooms), or placebo. The effective model included early area, fusiform gyrus, intraparietal sulcus, inferior frontal gyrus. We observed pattern increased self-inhibition both higher visual-association regions that consistent with preclinical findings. also reduced inhibition from earlier areas indicated top-down is enhanced during results were associated behavioural measures taken immediately scans, suggesting psilocybin-induced decreased sensitivity neural inputs perception findings inform our basic clinical understanding perception. They reveal mechanisms that, by affecting balance, increase impact feedback on perception, which could contribute seen experiences.

Language: Английский

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Effective connectivity of emotion and cognition under psilocybin

medRxiv (Cold Spring Harbor Laboratory), Journal Year: 2022, Volume and Issue: unknown

Published: Sept. 9, 2022

Abstract Classic psychedelics alter sense of self and patterns self-related thought. These changes are hypothesised to underlie their therapeutic efficacy across internalising pathologies such as addiction depression. Using resting-state functional MRI images from a randomised, double blinded, placebo-controlled clinical trial 24 healthy adults under 0.215mg/kg psilocybin, we investigated how psilocybin modulates the effective connectivity between resting state networks amygdala that involved in appraisal regulation emotion association with symptoms. The included default mode network (DMN), salience (SN) central executive (CEN). Psilocybin decreased top-down within DMN SN, while CEN increased. Effective were also associated altered meaning psilocybin. Our findings identify cognitive-emotional subjective effects attenuation signal potential biomarker psilocybin’s efficacy.

Language: Английский

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Divergent Perception: Framing Creative Cognition Through the Lens of Sensory Flexibility

The Journal of Creative Behavior, Journal Year: 2024, Volume and Issue: unknown

Published: Dec. 24, 2024

ABSTRACT Creativity is a cornerstone of human evolution and typically defined as the multifaceted ability to produce novel useful artifacts. Although much research has focused on divergent thinking, growing evidence underscores importance perceptual processing in fostering creativity, particularly through flexibility. The present work aims offer framework that relates creativity perception, showing how sensory affordances, especially ambiguous stimuli, can contribute generation ideas. In doing so, we contextualize phenomenon pareidolia, which involves seeing familiar patterns noisy or key mechanism idea generation—one central stages creative process. We introduce “divergent perception” describe process by individuals actively engage with affordances provided information, illustrate this concept could account for heightened observed psychedelic psychotic states. Moreover, explore perception cognitive mechanisms crucial focusing role attention. Finally, discuss future paths exploration including targeted manipulation stimulus characteristics investigation intricate interplay between bottom‐up top‐down processes.

Language: Английский

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Long-term effects of psilocybin on dynamic and effectivity connectivity of fronto-striatal-thalamic circuits

bioRxiv (Cold Spring Harbor Laboratory), Journal Year: 2024, Volume and Issue: unknown

Published: Nov. 7, 2024

Abstract Psilocybin has been shown to induce fast and sustained improvements in mental well-being across various populations, yet its long-term mechanisms of action are not fully understood. Initial evidence suggests that longitudinal functional structural brain changes implicate fronto-striatal-thalamic (FST) circuitry, a broad system involved goal-directed behavior motivational states. Here, we apply empirical methods computational modeling resting-state fMRI data from within-subject psilocybin trial psychedelic-naïve healthy volunteers. We first show increases FST dynamic activity four weeks after full dose psilocybin. then proceed mechanistically account for these increased dynamics, by showing reduced constraints underlie post Further, come along with bottom-up top-down modulation circuits. While cortical reductions linked regional 5-HT2A receptor availability, information outflow via subcortical limbic regions relate local D2 availability. Together, findings flexibility administration is serotonergic-mediated decreases flow dopaminergic-mediated flow. This re-organization circuits may represent common mechanism underling the potential clinical efficacy neuropsychiatric disorders including substance abuse, major depression, anorexia. Significance Statement Fronto-striatal-thalamic systems, which motivation reward, go through profound following administration. leveraged participants as well dosing. Computational revealed this caused on dynamics. Further included mediated serotonergic dopaminergic systems. reflect underlying symptoms diagnostic groups, such openness, improved well-being, anhedonia, apathy, craving.

Language: Английский

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Mystical Experience

Oxford University Press eBooks, Journal Year: 2023, Volume and Issue: unknown, P. 255 - 294

Published: Oct. 19, 2023

Abstract This chapter tackles the issue of whether mystical experiences are psychedelic -- that is, they mind-revealing. The argues to answer this question, we need be able define and cannot done, given their ineffability. Nevertheless, demonstrates how can deepen our understanding asks by engaging with ineffability seriously. As part demonstration, explores parallels between maximal uncertainty. It also highlights discusses significance emphasis many traditions place on subjective uncertainty intellectual humility.

Language: Английский

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