Psilocybin disintegrates brain networks momentarily

Your brain has a distinct pattern of activity inside your skull that is exclusive to you, like a neural fingerprint. Strong psilocybin doses cause the prints to momentarily disappear.

A recent brain scanning study published on July 17 in Nature demonstrates how the hallucinogenic drug psilocybin drastically alters how networks of nerve cells function in the brain, removing normal connectivity across brain areas. These brain scans, which were obtained prior to, during, and following a high dosage of psilocybin, provide additional insight into the effects of the drug, which is being researched for its potential to treat mental health conditions including depression.

The researchers utilized a rigorous technique for brain scans. Joshua Siegel is a neuroscientist and psychiatrist at Washington University School of Medicine in St. Louis. “We had a small number of people, just seven participants in the whole study,” he says. Over the duration of the trial, each participant had around 18 functional MRI brain scans, or about every other day.

As stated by Cornell University neuroscientist Alex Kwan, who was not involved in the work, “an unprecedented view on how brain connectivity evolves after a dose of psilocybin” is provided by that recurrent scanning.

During the initial phase of the study, Siegel and associates documented the individual’s resting-state brain activity, which consists of distinct patterns that arise similar to the whorls, loops, and arches seen in a fingerprint.

Afterwards, researchers observed what happened in the scanner after giving people 25 milligrams of psilocybin, a major component of some hallucinogenic mushrooms. Each subject also received a dosage of methylphenidate, the generic version of Ritalin, a brain stimulant, on a different day for comparison.

Psilocybin’s effects were significant and readily apparent. A neuroscientist at Washington University School of Medicine named Nico Dosenbach claims that psilocybin “had humongous acute effects on the human brain.” The methylphenidate was “way, way, way bigger than the active control.”

The default mode network, or DMN, is a brain circuit where some of the largest alterations were found. When nothing specific is going on, this coordinated group of brain regions is active. According to scientists, the DMN plays a part in the formation of our concept of self (SN: 7/3/09). According to Siegel, “it’s multiple brain regions in both hemispheres, but they’re all activating and deactivating in a very ordered, synchronous way.” “And when psilocybin is used, it basically turns into chaos.”

Dosenbach is able to confirm that using the medicine results in a loss of identity. Being one of the seven study volunteers as well as a researcher gave him a unique viewpoint on the effects of psilocybin on the brain. “After reading about it and giving it some thought, you experience it and realize, ‘Wow, that’s even more real.'”

The MRI scans revealed clues related to those encounters. The researchers observed that the participants’ neuronal fingerprints appeared to be erased by psilocybin. “You’d be like, ‘That is my face, and that is your face.’ And then you took a medicine, and we both had a puppy face — very similar, but very different from our normal faces,” says Dosenbach in an analogy to illustrate the brain alterations in the scans.

According to Siegel, the majority of psilocybin’s effects on the brain vanished a day after consumption. However, one alteration remained for three weeks. The DMN and a portion of the hippocampal, a region involved in memory, showed reduced cooperation. It is unknown at this time how long this alteration may persist, how it impacts the brain as a whole, or whether it may portend the therapeutic benefits of psilocybin. Data from four of the patients who returned for scans six to twelve months later did not show it, but the study did not have enough information to conclude that it had disappeared.

The results demonstrate that the effects of psychedelic drugs are complex and build upon previous research that aimed to understand how they alter the brain. According to Kwan, psilocybin is more complex than just adjusting brain activity levels. “The findings provide a more intricate and nuanced picture than previously believed about how psychedelics alter neural activity dynamics.”

According to recent studies, psychedelic drugs show potential as treatments for addiction, depression, and PTSD, among other conditions (SN: 12/3/21). Improved therapies for some of these illnesses may result from a better understanding of how these medications impact the brain in the hours, days, and months following use.