Distinct processing stages of cross-modal conflict in schizophrenia: The role of auditory cortex underactivation.

Background: The cross-modal conflict deficit is a key feature of schizophrenia. However, it remains largely unknown whether cross-modal conflict in schizophrenia diverges at distinct processing stages and its potential association with the auditory cortex.

Methods: In Experiment 1, we divided cross-modal conflict into semantic and response stages, and we investigated the cross-modal conflict between schizophrenia patients (n = 30) and health individuals (n = 32). In Experiment 2, we utilized tDCS (transcranial direct current stimulation) to inhibit the activity of the auditory cortex in healthy individuals (n = 20), and we substituted auditory sounds with visual words in healthy individuals (n = 34) in Experiment 3, exploring the association between the patients' cross-modal conflict patterns and the auditory cortex. Furthermore, we employed machine learning techniques to further validate the stability of the distinct pattern.

Results: We found that schizophrenia patients exhibited auditory dominance at the semantic conflict stage and visual dominance at the response conflict stage, contrary to healthy individuals. By causally interfering with the normal function of the auditory cortex in healthy individuals, we observed behavioral similarities to those with schizophrenia, supporting the critical role of insufficient auditory cortex activation in the early development of schizophrenia. The classification analysis further confirmed the double dissociation of cross-modal conflicts in schizophrenia and the role of auditory cortex underactivation.

Conclusions: These findings not only demonstrate a unique mechanism and its neural correlate in how schizophrenia patients cope with cross-modal conflicts but also provide potential early diagnostic markers or therapeutic targets for schizophrenia.