How psychedelic drug psilocybin works on brain

Date:
June 5, 2020
Source:
Johns Hopkins Medicine
Summary:
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.



FULL STORY ========================================================================== 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 3/4 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.


========================================================================== Story Source: Materials provided by Johns_Hopkins_Medicine. Note:
Content may be edited for style and length.


========================================================================== Journal Reference:
1. Frederick S. Barrett, Samuel R. Krimmel, Roland Griffiths, David A.

Seminowicz, Brian N. Mathur. Psilocybin acutely alters the
functional connectivity of the claustrum with brain networks
that support perception, memory, and attention. NeuroImage, 2020;
116980 DOI: 10.1016/ j.neuroimage.2020.116980 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/06/200605121512.htm

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