Hoping to glean new insights into how psychedelics alter a person’s conscious experience, the scientists conducted an experiment with DMT (dimethyltryptamine).
This is the natural psychedelic used in ayahuasca, in which participants drink an infusion in a spiritual ceremony typically led by a shaman.
The study, published in the journal PNASis the first to track brain activity before, during, and after the DMT experience in such detail.
Unlike other well-known psychedelics such as LSD or psilocybin, DMT’s effects on the brain are brief, lasting only minutes rather than hours.
The drug produces intensely altered states of consciousness, and people who have taken it often experience vivid and bizarre visions, or feel they have visited alternate realities or dimensions.
However, it is unclear how the compound actually alters brain function to explain these effects.
To find out, researchers at Imperial College London scanned the brains of 20 healthy volunteers who were given relatively high doses of DMT by injection.
Increased communications between brain systems
Two types of brain scans of the participants were performed before, during and after the trip: functional magnetic resonance imaging (Fmri) and electroencephalography (EEG).
FMRI measures the small changes in blood flow that occur with brain activity, while an EEG is conducted by attaching small sensors to a person’s scalp to pick up electrical signals produced by the brain.
The total psychedelic experience lasted approximately 20 minutes and, at regular intervals, the volunteers rated the subjective intensity of their experience on a scale of 1 to 10.
The fMRI scans showed changes in activity within and between brain regions, with increased communication between different areas and systems.
The changes have been most evident in areas related to what are called higher-level functions, such as the imagination.
“This work is exciting, as it provides the most advanced human neuroimaging view of the psychedelic state to date,” said Chris Timmerman of Imperial College London’s Center for Psychedelic Research, lead author of the study. that much of the brain’s function involves modeling or predicting its environment. Humans have unusually large brains and they model an unusually large amount of the world.”
He gave an example of how, when we observe optical illusions, our brains are actually filling in the blanks based on what we already know.
“What we’ve seen with DMT is that activity in highly evolved brain areas and systems that encode particularly high-level patterns becomes highly dysregulated under the influence of the drug, and this relates to the intense ‘trip’ of the drug itself.” “.
Relating brain activity to conscious experience
While it’s not the first study to image the brain during a psychedelic trip, it’s the first to combine the two imaging techniques to study what’s going on.
The researchers said the work provides further evidence of how DMT – and psychedelics more generally – exert their effects by disrupting high-level brain systems.
“Motivated by and based on our previous research with psychedelics, the present work has combined two complementary methods for imaging brain imaging.
Fmri has allowed us to see the whole brain, including its deeper structures, and Eeg has helped us visualize the brain’s fine-grained rhythmic activity,” said Professor Robin Carhart-Harris, founder of the Center for Psychedelic Research at Imperial College London – our results revealed that when a volunteer was on DMT there was marked dysregulation of some of the brain rhythms, which would normally be dominant.
The brain has changed its way of functioning into something completely more anarchic.”
He added that psychedelics are powerful tools for understanding how brain activity relates to conscious experience.
Researchers are continuing to explore how to prolong the peak of a psychedelic experience using continuous DMT infusion.
(Euronews of 23/03/2023)
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