How distinct autism and schizotypal trait dimensions influence neural predictive processing: An Event-related potential study.

The Predictive Processing framework offers insights into the neural mechanisms underlying autism and schizophrenia spectra. This study employed visual and auditory oddball tasks with varying difficulty levels to test whether brain-responses to unexpected events are different within these spectra. A total of 122 participants underwent EEG recordings and completed self-reports of autistic and schizotypal traits. Results showed that increased task difficulty significantly reduced P300 amplitudes across both sensory modalities. Higher Restricted Interests and Detail Orientation autistic traits were associated with enhanced N2 amplitudes in the difficult visual task, but there were no effects in the P300 time-window. Bayesian analyses yielded moderate evidence against any reliable association between P300 amplitudes and both autistic traits and schizotypy. Early auditory N1-P2 showed no credible relationships with schizotypal traits and only weak, task-dependent associations with autistic communication difficulties. Our study contributes to the growing literature on neural variability in autism and schizophrenia, emphasizing the importance of symptom-specific research and paving the way for more targeted investigations on predictive processing mechanisms. Moreover, the divergent findings for communication versus restricted-interests traits strengthen proposals that social and non-social dimensions in autism rely on distinct neural processes.