Perception is in the Details. A Predictive Processing Account of the Effects of 5-Hydroxytryptamine 2A (5-HT2A) Agonists On Perception
This paper uses the Predictive Processing framework to model the effect of 5-Hydroxytryptamine 2A (5-HT2A) agonists such as Psilocybin on the brain. This framework is becoming increasingly popular, explaining cortical processes using key concepts such as the brain as prediction machine (Dayan, Hinton, & Neal, 1995; Hohwy, 2007), the free energy principle (Friston, 2010) and the hierarchical organization of the brain (Friston, 2005). Our model explains results from studies regarding 5-HT2A agonists as stemming from the distribution of predictions from affected areas becoming more diffuse due to over excitability of layer 5-pyramidal neurons. These diffuse predictions create a higher entropic state in the brain. Lower areas in the brain now classify incoming data into more granular bins which leads to higher prediction errors. We show that the brain’s attempts to minimise higher levels of prediction error while being in this state explain the core effects of the psychedelic experience.
Following her BSc in Physics from the Hebrew University, Sarit worked for the forensic department for a few years then traveled the world teaching and studying martial arts and dance. She is currently completing a master’s degree in Cognitive Neuroscience at the Donders Institute for Brain, Cognition and Behaviour. Her research has been focused on using ideas from the Predictive Coding framework to understand how the brain creates prediction and how these predictions might be changed and updated to allow the brain to learn.