Auditory prediction errors and auditory white matter microstructure as predictors of psychotic experiences in healthy individuals

Our sensory systems actively predict sensory information based on previously learnt patterns. An inability to accurately predict forthcoming information results in prediction errors. Individuals with schizophrenia consistently show reduced auditory prediction errors as well as reduced microstructure in auditory white matter pathways. However, it is not clear if also healthy individuals with psychotic experiences demonstrate such deficits. Participants underwent electroencephalography (EEG) recordings while listening to a simple two-tone duration deviant oddball paradigm (N=103) and a stochastic oddball paradigm (N=89). A subset of participants (N=89) also underwent diffusion-weighted magnetic resonance imaging (MRI), from which fractional anisotropy (FA), a measure of overall white matter microstructure, was obtained for auditory pathways namely the auditory interhemispheric pathway, as well as the left and right arcuate fasciculi. We investigated both structural and functional predictors of positive psychotic experiences in healthy participants as measured by the Community Assessment for Psychic Experiences positive dimension (CAPE+) scores. Prediction errors evoked by the classical oddball paradigm failed to reveal significant effects, whereas the stochastic oddball paradigm revealed significant clusters at typical mismatch negativity periods predictive of CAPE+ scores. Furthermore, we show that white matter microstructure from auditory pathways in addition to mismatches significantly predict CAPE+ scores. We suggest that structural and functional prediction error measures together may have potential in predicting psychotic experiences in the healthy population.