Psychedelics: How do they work?
In this blog post, I will explain what makes a drug psychedelic and the impact that it has on your brain. For our purposes I will be focusing on psilocybin, the active ingredient in magic mushrooms. Although different psychedelics have many similar neurological effects, information about psilocybin’s affects is the most available.
A Chemical Flood
The main way that psychedelics affect your brain is through their manipulation of the chemical serotonin, a hormone involved in the regulation of emotions, mood, and perception of external stimuli[1]. When psilocybin is ingested, it dissolves in your stomach and takes the form of a chemical called psilocin. Psilocin then enters the brain through the bloodstream, where it takes effect.
Psilocin molecules are extremely similar in structure to serotonin molecules, allowing them to lock snugly into place in the brain’s serotonin receptors. Once in place, they force the brain to secrete serotonin for hours on end.
By flooding the brain with serotonin, psilocybin causes dramatic effects on your subjective experience of the world and can result in an alteration of the perception of stimuli like light, sound, and texture. This may explain why people who ingest magic mushrooms often report having enhanced visual acuity, increased auditory sensitivity, and seeing objects “flow” or “move” before their very eyes.
A Buzz of Activity
Research also shows that psilocybin causes a dramatic increase in brain activity, or so-called “Brain entropy”[2], meaning that parts of the brain normally uncommunicative suddenly begin to talk to each other at length.
The diagram above shows how neural connectivity between various sections of the brain increase dramatically while on psilocybin. This could explain various anecdotal reports of experiences like synesthesia (i.e., seeing sounds or hearing colors) while on magic mushrooms.
Ego Suppression
Another interesting facet of many psychedelic experiences is the affect they have on a collection of brain structures called the “Default Mode Network”, which is associated with self-perception and self-conscious thought. Through brain scans and imaging technology, researchers have found that during psilocybin sessions, blood flow to the default mode network decreases drastically.[3]
“If the ego has an address in the brain it’s somewhere in this network,” says author of 6 New York Times best sellers and multiple book awards Micheal Pollan in his 2018 novel “How to Change Your Mind”. In his novel, he explores promising new research into the science and application of psychedelics and touches on his own unique experiences with them in therapeutic settings.
Pollan's words are an echoing of what is now a commonly held belief among experts in the field of psychedelic therapy, that the default mode network can be linked to what we might otherwise call the “ego”, the part of the brain that experiences “I” as a separate entity from the rest of the world.
What does it mean?
So what does all this mean? Well, as the available body of psychedelic research continues to grow, we will have more and more information and specificity about the affects psychedelics have on the brain, as well as their potential uses and real-life applications. For now, it seems that psychedelics are able to induce altered states through increasing brain activity and shutting down the parts of the brain associated with normal conscious thought.
Works Cited
[1] Jarrett, C. (2020, April 8). How do psychedelics affect the brain? BBC Science Focus Magazine. Retrieved October 5, 2021, from https://www.sciencefocus.com/the-human-body/how-do-psychedelics-affect-the-brain/.
[2]Tagliazucchi, E., Carhart-Harris, R., Leech, R., Nutt, D., & Chialvo, D. R. (2014). Enhanced repertoire of brain dynamical states during The psychedelic experience. Human Brain Mapping, 35(11), 5442–5456. https://doi.org/10.1002/hbm.22562
[3]Carhart-Harris, R. L., Erritzoe, D., Williams, T., Stone, J. M., Reed, L. J., Colasanti, A., Tyacke, R. J., Leech, R., Malizia, A. L., Murphy, K., Hobden, P., Evans, J., Feilding, A., Wise, R. G., & Nutt, D. J. (2012). Neural correlates of the psychedelic state as determined by fmri studies with psilocybin. Proceedings of the National Academy of Sciences, 109(6), 2138–2143. https://doi.org/10.1073/pnas.1119598109
