fbpx

Exerpts from the publication

Background
The emerging novel therapeutic psilocybin produces psychedelic effects via engagement of cerebral serotonergic targets by psilocin (active metabolite). The serotonin 2A receptor critically mediates these effects by altering distributed neural processes that manifest as increased entropy, reduced functional connectivity (FC) within discrete brain networks (i.e., reduced integrity) and increased FC between networks (i.e., reduced segregation). Reduced integrity of the default mode network (DMN) is proposed to play a particularly prominent role in psychedelic phenomenology, including perceived ego-dissolution.

Methods
Here, we investigate the effects of a psychoactive peroral dose of psilocybin (0.2–0.3 mg/kg) on plasma psilocin level (PPL), subjective drug intensity (SDI) and their association in fifteen healthy individuals. We further evaluate associations between these measures and resting-state FC, measured with functional magnetic resonance imaging, acquired over the course of five hours after psilocybin administration.

Results
We show that PPL and SDI correlate negatively with measures of network integrity (including DMN) and segregation, both spatially constrained and unconstrained. We also find that the executive control network and dorsal attention network desegregate, increasing connectivity with other networks and throughout the brain as a function of PPL and SDI.

Conclusions
These findings provide direct evidence that psilocin critically shapes the time course and magnitude of changes in the cerebral functional architecture and subjective experience following psilocybin administration. Our findings provide novel insight into the neurobiological mechanisms underlying profound perceptual experiences evoked by this emerging transnosological therapeutic and implicate the expression of network integrity and segregation in the psychedelic experience and consciousness.

Read more

Long-term Follow-up of Psilocybin-facilitated Smoking Cessation

Matthew W. Johnson, PhD, Albert Garcia-Romeu, PhD, and Roland R. Griffiths, PhD
July 2016

Optimal dosing for psilocybin pharmacotherapy: Considering weight-adjusted and fixed dosing approaches

Albert Garcia-Romeu, Frederick S Barrett, Theresa M Carbonaro, Matthew W Johnson, Roland R Griffiths
February 2021

The cost-effectiveness of MDMA-assisted psychotherapy for the treatment of chronic, treatment-resistant PTSD

Elliot Marseille , James G. Kahn, Berra Yazar-Klosinski, Rick Doblin
October 2020

Integrating psychotherapy and psychopharmacology: psychedelic-assisted psychotherapy and other combined treatments

Kyle T. Greenway , Nicolas Garel , Lisa Jerome & Allison A. Feduccia
June 2020

Details