New research using advanced brain imaging has furthered scientists’ understanding of how psychedelics change conscious experience.
A group of 20 volunteers were given the psychedelic compound DMT (dimethyltryptamine), while detailed brain imaging was used to assess how it alters brain function.
Researchers from Imperial College London found increased communication between different areas and systems within the brain, with the most notable changes seen in the ‘higher level’ functions like imagination.
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Senior author Prof Robin Carhart-Harris, founder of the Centre for Psychedelic Research at Imperial College London who is now working at the University of California, San Francisco, said: “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.”
It is the first study to examine brain activity in detail, using two types of brain imaging before, during and after the DMT experience.
DMT is found naturally in certain plants and animals and is used in a psychedelic brew made from leaves and vines that is commonly used in ceremonies in south American and central American countries.
DMT can trigger intense, altered states of consciousness, with bizarre visions a common feature. It can also bring on a sense of experiencing alternative realities. However, exactly how it changes brain function to bring about such effects had been relatively unknown.
First author Dr Chris Timmerman, from the Centre for Psychedelic Research at Imperial College London, said: “This work is exciting as it provides the most advanced human neuroimaging view of the psychedelic state to-date.
“One increasingly popular view is that much of brain function is concerned with modelling or predicting its environment. Humans have unusually big brains and model an unusually large amount of the world.
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“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’.”
For the study, the volunteers were injected with the drug while functional magnetic resonance imaging (fMRI) and electroencephalography (EEG) brain imaging was used during the psychedelic experience, which went on for about 20 minutes. The volunteers were asked to rate the intensity of their experience at regular intervals.
The study was the first to combine imaging techniques to examine brain activity during psychedelic experience, and it picked up the increased connectivity across the brain.
Some of the researchers from Imperial College are now advising on a commercial trial looking to see if DMT could be used for people with depression.
Read the study in the journal Proceedings of the National Academy of Sciences.
