Latin for “hidden away” the word Claustrum also applies to a central and deep down region of the brain that some neuroscientists believe could be the region most responsible for consciousness, our sense of self, and the ego. An “extremely thin sheet of neurons deep within the cortex,” it nonetheless reaches out to touch every other part of the cortex.

The claustrum also contains, according to a new study from Johns Hopkins University, profoundly large numbers of receptors targeted by psilocybin, a psychedelic compound found in mushrooms, LSD, and other substances. Cells have receptors on the exterior membrane which receive particular chemicals like hormones, causing the cell to react in certain ways when receiving these biological signals.

When serotonin 2a 5-HT2A receptors in the claustrum receive psilocybin, there was a demonstrated reduction of activity in the claustrum by 15-30%.

Psilocybin is one of the most common hallucinogenic/psychedelic compounds, and makes up to 75% of the total psychedelic compound profile of psychedelic mushrooms. In 2006 Johns Hopkins began studying psilocybin as a possible treatment for a wide variety of psychiatric conditions, such as anxiety, depression, PTSD, and more, and has since published extensively on it and other compounds like MDMA and DMT.

Leggo my Ego

The study, published in NeuroImage by Frederick Barrett Ph.d., reports that claustrum activity is stimulated on the onset of doing a cognitively demanding task. This neural imaging evidence also linked claustrum activity with other large-scale brain networks called the “default mode network” or NMN.

“These observations are unique to the claustrum, distinct from the role of neighboring structures such as the insula and putamen, and consistent with the idea that the claustrum supports the co-activation of widespread cortical regions participating in the networks necessary for cognitive control of behavior,” writes Barrett in his paper.

Examining the claustrum in 15 healthy individuals, Barrett et al. found that psilocybin decreased activity in the claustrum by 15-30% while changing the way it communicated with other regions of the brain relating to attention, remembering, hearing, and decision-making.

“…the subjective effects of psilocybin, and ineffability in particular, were found to be associated with measures of claustrum activity,” writes Barrett. “…while psilocybin-evoked reductions in DMN connectivity correlate with ratings of subjective effects and peak mystical, or ego-dissolutive experiences”.

Ineffability is the inability to put an experience into words and was one of the subjective effects of psilocybin which the authors measured through a survey, along with others like now-ness, tranquility, and the reduction of the sense of self and the melding with a greater feeling of wholeness.

The researchers will look to continue to build on this body of work involving the claustrum, and see if the mysterious cortical region communicates a certain way in people with certain psychiatric disorders such as depression and substance use disorder.

The idea is that if the claustrum is communicating in a way that exacerbates the effects of these disorders, psilocybin can cool its response and perhaps alleviate the symptoms.

Continue exploring this topic — Study of DMT Users by Johns Hopkins Reports 89% Positive Changes in Life Satisfaction