New research published in Biological Psychology sheds light on the neurophysiological underpinnings of the psychedelic experience. The study provides new details about how psilocybin — the active component in “magic” mushrooms — changes the communication patterns between regions of the brain.
“Psychedelics are currently being investigated for the treatment of psychiatric disorders. However, it is still unclear how they change brain activity and connectivity to induce their unique effects,” explained study author Katrin Preller of the University of Zurich and Yale University.
“We therefore conducted a study to investigate the time-dependent effects of psilocybin on brain connectivity and the association between changes in brain connectivity and receptor pharmacology.”
In the study, 23 healthy human participants underwent MRI brain scanning 20 minutes, 40 minutes, and 70 minutes after receiving either psilocybin or a placebo. The researchers observed reduced connectivity between brain areas involved in planning and decision-making but increased connectivity between areas involved in sensation and movement while the participants were under the influence of the psychedelic drug.
Preller and her colleagues conducted a similar study on LSD, and obtained “virtually identical” results.
“Psilocybin – similar to LSD – induced a pattern of brain connectivity that is characterized by increased synchronization of sensory brain regions and decreased connectivity of associative networks,” she told PsyPost.
“Increased sensory processing but altered integration of this sensory information may therefore underlie the psychedelic state and explain the symptoms induced by psilocybin. Furthermore, this pattern of changes in connectivity was closely associated with spatial expression of the serotonin 2A and 1A receptors – pinpointing these receptors as critical for the effects of psilocybin.”
Another drug called ketanserin, a serotonin 2A antagonist, prevented the effects of both psilocybin and LSD, suggesting that changes in brain connectivity caused by these psychedelic drugs are linked to stimulation of the serotonin 2A receptor.
“In this study we investigated different time points from administration to subjective peak effects. Future studies need to investigate how psilocybin impacts brain connectivity during a later phase and post-acutely,” Preller noted.
The study, “Psilocybin induces time-dependent changes in global functional connectivity“, was authored by Katrin H. Preller, Patricia Duerler, Joshua B. Burt, Jie Lisa Ji, Brendan Adkinson, Philipp Stämpfli, Erich Seifritz, Grega Repovs, John H. Krystal, John D. Murray, Alan Anticevic, and Franz X. Vollenweider.