Study Reveals DMT’s Effects on the Human Brain in Unprecedented Detail

A new study has unveiled how psychedelics achieve their perception-altering effects in the human brain. The research used a powerful combination of brain analysis techniques to provide the clearest picture yet of how the short-acting, but powerful psychedelic DMT (dimethyltryptamine) affects brain activity.

The research was published in the journal PNAS.

DMT: The key ingredient in ayahuasca

DMT has a storied history. Used for thousands of years in rituals and other ceremonies across Central and South America, it is the key active component of the potent psychedelic brew ayahuasca. More recently, the compound was synthetically created by German–Canadian chemist Richard Manske in 1931.

The DMT experience makes it particularly promising as a therapeutic psychedelic. The University of New Mexico’s Professor Rick Strassman, an expert in the compound, describes it as inducing effects like “visions, voices, a seeming separation of consciousness from the body, extreme emotional states and contact with seemingly discarnate intelligences.” But the compound does so over relatively short periods of time as compared to other classic psychedelics such as psilocybin. That makes it much more flexible as a tool for psychedelic-assisted psychotherapy. But no previous study has exploited this short duration to study the effects of DMT on the human brain in high detail before, during and after a DMT trip.

That has all changed with the release of the new paper. “This work is exciting as it provides the most advanced human neuroimaging view of the psychedelic state to date,” said study first author Dr. Chris Timmermann, from the Centre for Psychedelic Research at Imperial College London.

Brain activity analysis

Timmermann and colleagues recruited 20 healthy volunteers, who were given a high-dose injection of DMT (20 mg) and then subjected to two types of brain analysis. They were fitted with an electroencephalography (EEG) cap and placed inside a functional magnetic resonance imaging (fMRI) scanner.

The cap measured electrical signals from the volunteers’ scalps over 31 different sites. At the same time, the fMRI scan detected the movement of oxygenated blood inside their brains as a proxy for brain activity. This allows the team to create a detailed image of their participants’ brain activity. Their trip lasted around 20 minutes in total. Over that period, there were dramatic changes in their brains.

Brain activity is usually segregated into discrete networks. After DMT injection, those networks appeared to break down, meaning that overall brain connectivity increased. This aligns with a previous study of the brain response to psilocybin published by senior author Robin Carhart-Harris. The most significant changes were detected in brain areas linked to high-level cognitive functions like imagination.

Timmermann summarized the findings: “What we have seen with DMT is that activity in highly evolved areas and systems of the brain that encode especially high-level models becomes highly dysregulated under the drug, and this relates to the intense drug ‘trip’.”

The team now hopes to prolong DMT’s psychedelic “peak” through a continuous infusion protocol. Carhart-Harris, now of the University of California, San Francisco, added, “Our results revealed that when a volunteer was on DMT there was a marked dysregulation of some of the brain rhythms that would ordinarily be dominant. The brain switched in its mode of functioning to something altogether more anarchic. It will be fascinating to follow up on these insights in the years to come. Psychedelics are proving to be extremely powerful scientific tools for furthering our understanding of how brain activity relates to conscious experience.”

Reference: Timmermann C, Roseman L, Haridas S et al. Human brain effects of DMT assessed via EEG-fMRI. PNAS. 2023; 120: e2218949120. doi: 10.1073/pnas.2218949120.

This article is a rework of a press release issued by Imperial College London. Material has been edited for length and content. 

Correction: The image description erroneously suggested that Banisteriopsis caapi is a natural source of DMT in ayahuasca. Instead, it is a source of monoamine oxidase inhibitors (MAOIs) that extend the psychedelic experience.