This neuroimaging study (n=20) aimed to understand the effects of DMT (20mg) on the human brain. The researchers used EEG-fMRI (electroencephalography-functional MRI) to measure brain activity before, during, and after administering DMT to healthy volunteers. They found that DMT increased global functional connectivity (GFC), network disintegration and desegregation, and a compression of the principal cortical gradient. These changes were associated with the brain’s transmodal association pole, which is linked to species-specific psychological advancements and high expression of 5-HT2A receptors.

Abstract of Human brain effects of DMT assessed via EEG-fMRI

“Psychedelics have attracted medical interest, but their effects on human brain function are incompletely understood. In a comprehensive, within-subjects, placebo-controlled design, we acquired multimodal neuroimaging [i.e., EEG-fMRI (electroencephalography-functional MRI)] data to assess the effects of intravenous (IV) N,N-Dimethyltryptamine (DMT) on brain function in 20 healthy volunteers. Simultaneous EEG-fMRI was acquired prior to, during, and after a bolus IV administration of 20 mg DMT, and, separately, placebo. At dosages consistent with the present study, DMT, a serotonin 2A receptor (5-HT2AR) agonist, induces a deeply immersive and radically altered state of consciousness. DMT is thus a useful research tool for probing the neural correlates of conscious experience. Here, fMRI results revealed robust increases in global functional connectivity (GFC), network disintegration and desegregation, and a compression of the principal cortical gradient under DMT. GFC × subjective intensity maps correlated with independent positron emission tomography (PET)-derived 5-HT2AR maps, and both overlapped with meta-analytical data implying human-specific psychological functions. Changes in major EEG-measured neurophysiological properties correlated with specific changes in various fMRI metrics, enriching our understanding of the neural basis of DMT’s effects. The present findings advance on previous work by confirming a predominant action of DMT—and likely other 5-HT2AR agonist psychedelics—on the brain’s transmodal association pole, i.e., the neurodevelopmentally and evolutionarily recent cortex that is associated with species-specific psychological advancements, and high expression of 5-HT2A receptors.”

Authors: Christopher Timmermann, Leor Roseman, Sharad Haridas, Fernando E. Rosas, Lisa Luan, Hannes Kettner, Jonny Martell, David Erritzoe, Enzo Tagliazucchi, Carla Pallavicini, Manesh Girn, Andrea Alamia, Robert Leech, David J. Nutt & Robin L. Carhart-Harris

Summary of Human brain effects of DMT assessed via EEG-fMRI

DMT is a classic serotonergic psychedelic drug that induces an intense and immersive altered state of consciousness, characterized by vivid and complex imagery, and a sense of being transported to an alternative reality or dimension, without any diminishment in wakefulness.

Clinical trials of psychedelic therapy have yielded consistently promising safety and efficacy findings, suggesting that 5-HT2A receptor agonism is the trigger event in psychedelics’ therapeutic action.

Most human research with pure DMT involves an intravenous mode of administration. Previous functional MRI studies revealed decreased within-network functional connectivity (FC) and increased between-network FC (a globally hyperconnected brain state).

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Human brain effects of DMT assessed via EEG-fMRI

https://doi.org/10.1073/pnas.2218949120

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Cite this paper (APA)

Timmermann, C., Roseman, L., Haridas, S., Rosas, F. E., Luan, L., Kettner, H., ... & Carhart-Harris, R. L. (2023). Human brain effects of DMT assessed via EEG-fMRI. Proceedings of the National Academy of Sciences, 120(13), e2218949120.

Study details

Compounds studied
DMT

Topics studied
Neuroscience

Study characteristics
Original Placebo-Controlled Single-Blind Randomized

Participants
20 Humans

Authors

Authors associated with this publication with profiles on Blossom

Chris Timmermann
Chris Timmerman is a postdoc at Imperial College London. His research is mostly focussed on DMT.

David Nutt
David John Nutt is a great advocate for looking at drugs and their harm objectively and scientifically. This got him dismissed as ACMD (Advisory Council on the Misuse of Drugs) chairman.

Robin Carhart-Harris
Dr. Robin Carhart-Harris is the Founding Director of the Neuroscape Psychedelics Division at UCSF. Previously he led the Psychedelic group at Imperial College London.

Institutes

Institutes associated with this publication

Imperial College London
The Centre for Psychedelic Research studies the action (in the brain) and clinical use of psychedelics, with a focus on depression.

Compound Details

The psychedelics given at which dose and how many times

DMT 20 mg | 1x

Linked Research Papers

Notable research papers that build on or are influenced by this paper

Time-resolved network control analysis links reduced control energy under DMT with the serotonin 2a receptor, signal diversity, and subjective experience
This re-analysis (n=14) applies a receptor-informed network control theory framework to investigate the effects of DMT on the brain's control energy landscape. It reveals that DMT, like LSD and psilocybin, reduces global control energy, with these trajectories correlating with EEG signal diversity and subjective intensity ratings. Furthermore, the regional effects of DMT correlate with serotonin 2a receptor density, demonstrating a potential proof-of-concept for predicting pharmacological intervention effects on brain dynamics using control models.