Ancient hallucinogen offers deep insights in brain-scan research

The brew is so potent that those who take it report not only powerful hallucinations but near-death experiences, contact with higher-dimensional beings, and life-transforming voyages through alternative realities.

Now, scientists have gleaned deep insights of their own by monitoring the brain under the influence of DMT, or dimethyltryptamine, the psychedelic compound found in the Amazonian drink ayahuasca.

The recordings reveal a profound impact across the brain, particularly in areas instrumental in planning, language, memory, complex decision-making and imagination.

"People describe leaving this world and breaking through into another that is incredibly immersive and richly complex, sometimes being populated by other beings that they feel might hold special power over them, like gods,” said Robin Carhart-Harris, a professor of neurology and psychiatry at the University of California, San Francisco.

Human have sought the altered states brought on by ayahuasca for at least 1,000 years. The brew is typically made by boiling Banisteriopsis caapi, a giant vine, with leaves from the Psychotria viridis shrub.

For the latest study, Chris Timmermann, the head of the DMT research group at Imperial College London, recruited 20 healthy volunteers who received a 20mg injection of DMT and a placebo on separate visits to the lab. All were screened to ensure they were physically and mentally suitable for the study.

Using electroencephalography and functional magnetic resonance imaging), the scientists recorded the participants’ brain activity before, during and after the drug took hold.

The results, published in the journal Proceedings of the National Academy of Sciences, are the most advanced picture yet of the human brain on psychedelics. They show how the brain’s hierarchical organisation breaks down, electrical activity becomes anarchic, and connectivity between regions soars. “The stronger the intensity of the experience, the more hyperconnected were those brain areas,” said Timmermann.

This ability to make brain activity more fluid and flexible is thought to underpin not only the profound psychedelic experience but the promising results from early clinical trial patients who were given DMT in combination with psychotherapy to treat depression.

"This is just the beginning in cracking the question of how DMT works to alter consciousness so dramatically,” said Carhart-Harris.