Researchers study effects of psilocybin magic mushrooms on brain activity

Back in 2012, a few studies on psilocybin and the brain were published. In several studies, healthy volunteers underwent MRIs, finding that psilocybin reduced brain activity in specific areas. 

Psilocybin and Effects on the Brain

The senior author of those 2012 studies, renown Professor David Nutt,said at the time: “Psilocybin actually caused activity to decrease in areas that have the densest connections with other areas. These hubs constrain our experience of the world and keep it orderly. We now know that deactivating these regions leads to a state in which the world is experienced as strange.” 

A few years later, in 2018, the first study of the dose effects of psilocybin found that cognitive impairment was not observed on the 20 hallucinogen users recruited for the study. They were administered the following blinded drug administration sessions:

  • 10, 20, and 30 mg/70 kg psilocybin OR 400 mg/70 kg DXM; and placebo)

Some effects were observed on psychomotor performance, working memory, episodic memory, associative learning, and visual perception.

Psilocybin Effects on the Claustrum

In 2020, Johns Hopskins University released another publication which found that psilicybin reduced neural activity in the claustrum 15% to 30%, which was associated with stronger subjective (mystical or emotional) experiences. The claustrum is, put simply, a grey matter lining that is involved in functions such as sensations and rewarding behaviour. They also found that the claustrum changed how it communicated in hearing, attention, decision-making and remembering brain regions. The MRI imaging of the claustrum is the key to helping further research for treatment-resistent depression and substance use disorders..

Psilocybin Brain Study on Treatment-Resistant Depression

On the other hand, a psilocybin study published in 2022 — also contributed to by Professor Nutt, as well as several other well-known names in the psychedelic field, such as Robin Earhart-Harris — showed that psilocybin therapy caused quite a bit of transformation in depressed people’s brains. 

The two trials performed had the following dosing regimen for patients with treatment-resistant depression: 

  • 10 mg and 25 mg, 7 days apart 
  • 25 mg x2 oral psilocybin, 3 weeks apart, plus 6 weeks of daily placebo (‘psilocybin arm’) OR 1 mg x2 oral psilocybin, 3 weeks apart, plus 6 weeks of 10-20mg daily escitalopram (a common SSRI drug used for depression). Interestingly, those patients taking escitalopram did not have the same recorded changes as those not.

In this case, the conclusion was that psilocybin therapy could provide opportunity for new psychiatric treatment options.