Subacute Effects of the Psychedelic Ayahuasca on the Salience and Default Mode Networks

This randomized placebo-controlled study (n=43) inspects the subacute effects of psychedelic ayahuasca on the primary sensory brain networks and networks supporting higher-order effective and self-referential functions in healthy participants (21 placebo/22 ayahuasca) using task-free functional magnetic resonance imaging data (fMRI). The studies propose that connectivity of primary sensory networks did not differ between groups however, the increase in salience network connectivity was linked to altered somesthesia scores, lowered default mode network connectivity was linked to altered volition scores.

Abstract

Background: Neuroimaging studies have just begun to explore the acute effects of psychedelics on large-scale brain networks’ functional organization. Even less is known about the neural correlates of subacute effects taking place days after the psychedelic experience. This study explores the subacute changes of primary sensory brain networks and networks supporting higher-order affective and self-referential functions 24 hours after a single session with the psychedelic ayahuasca.

Methods: We leveraged task-free functional magnetic resonance imaging data 1 day before and 1 day after a randomized placebo-controlled trial exploring the effects of ayahuasca in naïve healthy participants (21 placebo/22 ayahuasca). We derived intra- and inter-network functional connectivity of the salience, default mode, visual, and sensorimotor networks, and assessed post-session connectivity changes between the ayahuasca and placebo groups. Connectivity changes were associated with Hallucinogen Rating Scale scores assessed during the acute effects.

Results: Our findings revealed increased anterior cingulate cortex connectivity within the salience network, decreased posterior cingulate cortex connectivity within the default mode network, and increased connectivity between the salience and default mode networks 1 day after the session in the ayahuasca group compared to placebo. Connectivity of primary sensory networks did not differ between groups. Salience network connectivity increases correlated with altered somesthesia scores, decreased default mode network connectivity correlated with altered volition scores, and increased salience default mode network connectivity correlated with altered affect scores.

Conclusion: These findings provide preliminary evidence for subacute functional changes induced by the psychedelic ayahuasca on higher-order cognitive brain networks that support interoceptive, affective, and self-referential functions.”

Authors: Lorenzo Pasquini, Fernanda Palhano-Fontes & Draulio B. Araujo

Study details

Compounds studied
Ayahuasca

Topics studied
Neuroscience

Study characteristics
Placebo-Controlled Double-Blind Randomized Bio/Neuro

Participants
43

Authors

Authors associated with this publication with profiles on Blossom

Fernanda Palhano Xavier de Fontes
Fernanda Palhano Xavier de Fontes is a research engineer at the Brain Institute, UFRN. Her main areas of interest are psychedelics, psychiatry, and neuroimaging techniques such as fMRI and electroencephalography.

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