Reduced top-down connectivity as an underlying mechanism for psychotic experiences in healthy people

Perception results from our brain’s ability to make predictive models of sensory information. Recently, it has been proposed that psychotic traits may be linked to impaired predictive processes. Here, we examine the brain dynamics underlying prediction formation in a population of healthy individuals with a range of psychotic experiences. We designed a novel paradigm, which incorporated both stable and volatile sound sequences by manipulating their probability. We measured prediction error with electroencephalography and gauged prediction formation explicitly by behaviourally recording sensory ‘regularity’ learning errors. Critically, we show that top-down frontotemporal connectivity may be a neural mechanism by which impaired regularity learning influences psychotic experiences. These findings further our understanding of the neurobiological underpinnings of prediction formation and provide evidence for a continuum of psychosis in the healthy, non-clinical population. One Sentence Summary Healthy individuals with psychotic experiences have impaired sensory learning, mediated by reduced top-down frontotemporal connectivity.