Predictive coding and hallucinations: a question of balance: Comment on Powers, Mathys, and Corlett (2017)“Pavlovian conditioning induced hallucinations result from …

A principle of the cognitive neuropsychiatric approach is to go beyond surface phenomenology and to comprehend the symptoms of psychiatric illness in terms of altered functioning within the normal system. This requires us to “take the best cognitive models for a range of normal psychological functions and treat them as if psychiatric phenomena fall within their ambit”(David & Halligan, 1996) bridging the gap between high-level experiences or behaviours and the neural systems that underpin them (Halligan & David, 2001). A recent study by Powers, Mathys, and Corlett (2017) applies computational modelling in the context of an elegant experimental design to achieve this. In doing so, they show how this principled approach may provide mechanistic understandings of how symptoms of psychosis may emerge, evolve, and interact. Their work draws on the principles of predictive coding (PC)(Rao & Ballard, 1999 …