How psychedelic drug psilocybin works on brain

June 5, 2020

Science Daily/Johns Hopkins Medicine

To see how psychedelics impact the claustrum, a mysterious region of the brain believed to control the ego, researchers compared the brain scans of people after they took psilocybin with their scans after taking a placebo.

Perhaps no region of the brain is more fittingly named than the claustrum, taken from the Latin word for "hidden or shut away." The claustrum is an extremely thin sheet of neurons deep within the cortex, yet it reaches out to every other region of the brain. Its true purpose remains "hidden away" as well, with researchers speculating about many functions. For example, Francis Crick of DNA-discovery fame believed that the claustrum is the seat of consciousness, responsible for awareness and sense of self.

What is known is that this region contains a large number of receptors targeted by psychedelic drugs such as LSD or psilocybin ¾ the hallucinogenic chemical found in certain mushrooms. To see what happens in the claustrum when people are on psychedelics, Johns Hopkins Medicine researchers compared the brain scans of people after they took psilocybin with their scans after taking a placebo.

Their findings were published online on May 23, 2020, in the journal NeuroImage.

The scans after psilocybin use showed that the claustrum was less active, meaning the area of the brain believed responsible for setting attention and switching tasks is turned down when on the drug. The researchers say that this ties in with what people report as typical effects of psychedelic drugs, including feelings of being connected to everything and reduced senses of self or ego.

"Our findings move us one step closer to understanding mechanisms underlying how psilocybin works in the brain," says Frederick Barrett, Ph.D., assistant professor of psychiatry and behavioral sciences at the Johns Hopkins University School of Medicine and a member of the school's Center for Psychedelic and Consciousness Research. "This will hopefully enable us to better understand why it's an effective therapy for certain psychiatric disorders, which might help us tailor therapies to help people more."

Because of its deep-rooted location in the brain, the claustrum has been difficult to access and study. Last year, Barrett and his colleagues at the University of Maryland, Baltimore, developed a method to detect brain activity in the claustrum using functional magnetic resonance imaging (fMRI).

For this new study, the researchers used fMRI with 15 people and observed the claustrum brain region after the participants took either psilocybin or a placebo. They found that psilocybin reduced neural activity in the claustrum by 15% to 30%. This lowered activity also appeared to be associated with stronger subjective effects of the drug, such as emotional and mystical experiences. The researchers also found that psilocybin changed the way that the claustrum communicated with brain regions involved in hearing, attention, decision-making and remembering.

With the highly detailed imaging of the claustrum provided by fMRI, the researchers next hope to look at the mysterious brain region in people with certain psychiatric disorders such as depression and substance use disorder. The goal of these experiments will be to see what roles, if any, the claustrum plays in these conditions. The researchers also plan to observe the claustrum's activity when under the influence of other psychedelics, such as salvinorin A, a hallucinogen derived from a Mexican plant.

https://www.sciencedaily.com/releases/2020/06/200605121512.htm

Classic psychedelic use protective with regard to psychological distress and suicidality

January 21, 2015

Science Daily/SAGE Publications

Classic psychedelics, such as LSD, psilocybin mushrooms and mescaline, previously have been shown to occasion lasting improvements in mental health. But researchers led by University of Alabama at Birmingham School of Public Health investigators wanted to advance the existing research and determine whether classic psychedelics might be protective with regard to suicidal thoughts and behaviors.

Approximately 30,000 lives in the United States are claimed by suicide every year, and more than 90 percent of victims have been diagnosed with mental illness, according to the National Alliance on Mental Illness.

Using data from more than 190,000 respondents of the National Survey on Drug Use and Health from 2008-2012, the researchers found that those who reported ever having used a classic psychedelic drug in their lifetime had a decreased likelihood of psychological distress in the past month, and decreased suicidal thinking, planning and attempts in the past year.

"Despite advances in mental health treatments, suicide rates generally have not declined in the past 60 years. Novel and potentially more effective interventions need to be explored," said Peter S. Hendricks, Ph.D., assistant professor in the Department of Health Behavior and lead study author. "This study sets the stage for future research to test the efficacy of classic psychedelics in addressing suicidality as well as pathologies associated with increased suicide risk (e.g., affective disturbance, addiction and impulsive-aggressive personality traits)."

Hendricks says the take-home message from this study is that classic psychedelics may hold great promise in the prevention of suicide and evaluating the therapeutic effectiveness of classic psychedelics should be a priority for future research.

https://www.sciencedaily.com/releases/2015/01/150121093544.htm