REBUS and the Anarchic Brain: Toward a Unified Model of the Brain Action of Psychedelics
Pharmacological Reviews June 20, 2019 R.L. Carhart-Harris, K.J. Friston 1,163 citations
Psychedelics work by relaxing the precision of deeply held beliefs (high-level priors) in the brain, allowing more bottom-up information flow from intrinsic sources like the limbic system. This process, called REBUS (Relaxed Beliefs Under Psychedelics) and the anarchic brain, integrates the free-energy principle with the entropic brain hypothesis. The model explains how psychedelics can revise pathologically over-weighted priors underlying mental illness, and also potentially alter strongly held priors related to political, religious, or philosophical perspectives. The authors propose that this relaxation and sensitization of priors to bottom-up signaling enables therapeutic revision, especially when combined with appropriate intention, care, and context.