Brains of people who took hallucinogenic mushrooms were found to be disrupted by the neural networks related to self-consciousness

The principle by which psilocybin, a psychoactive extract of the Mexican magic mushroom that has recently been spotlighted as a candidate for antidepressant, works on the brain has been discovered. It is said that it temporarily disrupts the “default mode network” of the human brain involved in self-awareness, space, and time perception, preventing the corresponding nerve cells from performing synchronized functions. This is what the health and medical webzine “Health Day” reported on the 18th (local time) based on a paper by American researchers published in Nature.

The findings, led by researchers at Washington University School of Medicine in St. Louis, suggest that psilocybin may make brain connections more flexible, which could help people who experience rigid maladaptive patterns of thought and behavior. It could also lay the foundation for a better understanding of how the drug could be used to treat mental health conditions such as depression, the researchers said.

The researchers noted in a background note that psilocybin showed promise as a treatment for depression in the 1950s and 1960s, but research on it was halted in the late 1960s when the U.S. federal government deemed it an illegal drug. However, research on psilocybin has been revitalized in recent years since it was legalized in states such as Oregon and Colorado.

“We know a lot about the psychological effects of psilocybin and the molecular and cellular effects,” said study lead author Dr. Joshua Siegel, a neurologist at WUSTL. “But we don’t know much about what’s happening at the level that connects the two—at the functional brain network level.”

The researchers recruited a small group of adults who agreed to take psilocybin in a controlled setting. They administered 25 milligrams of psilocybin before and after the subjects underwent functional magnetic resonance imaging (fMRI) to measure activity in various brain regions, on average 18 times over three weeks.

The results showed that psilocybin causes a temporary desynchronization of the brain’s default mode network, a set of interconnected neurons that are all active when the brain is not performing any specific task and are primarily responsible for self-awareness and reflection.

Psilocybin temporarily disrupted the communication between neurons in this default mode network, causing them to become unsynchronized. When the effects of psilocybin wore off, the default mode network resumed functioning, but the small differences persisted for several weeks.

This study suggests that this desynchronization of the default mode network can lead to acute hallucinations, and provides strong evidence that it can contribute to changes in neural activity in brain regions that play a role in regulating self, emotions, and thoughts about life. For example, it could provide people with addictions with new perspectives on their addictions and relationships, or help them overcome depression.

However, experts point out that a verification process through large-scale clinical trials using diverse patient populations and factorial study designs is needed to investigate the efficacy of psychedelics such as psilocybin. It also seems necessary to investigate whether other psychedelics such as LSD or DMT and psychoactive substances such as MDMA (ecstasy) or ketamine have similar effects on communication between brain regions.

The paper can be found at the following link (