Researchers from Imperial College London uncover how DMT induces intense altered states of consciousness by changing brain activity

A study conducted at Imperial College London detailed brain imaging data from 20 healthy volunteers to reveal how the potent psychedelic compound DMT (dimethyltryptamine) alters brain function. During the immersive DMT experience researchers found there is increased connectivity across the brain, with more communication between different areas and systems. The changes to brain activity are most prominent in areas linked with “higher level” functions, such as imagination.

“One increasingly popular view is that much of brain function is concerned with modeling or predicting its environment. Humans have unusually big brains and model an unusually large amount of the world. For example, like with optical illusions, when we’re looking at something, some of what we’re actually seeing is our brain filling in the blanks based on what we already know. 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’,”  stated Chris Timmermann, PhD, a research associate at Imperial College London at the Centre for Psychedelic Research, and first author on the study.

Experts say that DMT’s effects on the brain are relatively brief, lasting a matter of minutes, rather than hours. DMT can produce intense and immersive altered states of consciousness, with the experience characterized by vivid and bizarre visions, a sense of “visiting” alternative realities or dimensions, and similarities with near death experiences. But exactly how the compound alters brain function to account for such effects has been unclear.

The study’s participants received a high dose of DMT (20mg, given intravenously), while simultaneously undergoing two types of brain imaging: functional magnetic resonance imaging (fMRI) and electroencephalography (EEG). The total psychedelic experience lasted about 20 minutes, and at regular intervals, volunteers provided a rating of the subjective intensity of their experience (on a 1 to 10 scale).

The fMRI scans reportedly found changes to activity within and between brain regions in volunteers under the influence of DMT. Effects included increased connectivity across the brain, with more communication between different areas and systems. These phenomena, termed “network disintegration and desegregation” and increased “global functional connectivity”, align with previous studies with other psychedelics. The changes to activity were most prominent in brain areas linked with ‘higher level’, human-specific functions, such as imagination, the researchers noted.

“Motivated by, and building on our previous research with psychedelics, the present work combined two complementary methods for imaging the brain. fMRI allowed us to see the whole of the brain, including its deepest structures, and EEG helped us view the brain’s fine-grained rhythmic activity,” commented Robin Carhart-Harris, founder of the Centre for Psychedelic Research at Imperial College London, and senior author on the paper. “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.”

To read the full study, visit PNAS.