Neural encoding of auditory processing in schizophrenia

Abstract

Auditory processing abnormalities are a core feature of schizophrenia and are linked to deficits in speech perception, cognitive function, and everyday communication. It remains unclear which stages of auditory processing are most disrupted and how these disruptions relate to symptoms at the level of population-wide neural representations. We used fMRI recordings acquired while individuals with schizophrenia and matched healthy controls completed a controlled block-design speech-perception task. Voxel-wise encoding models mapped self-supervised speech-model representations, together with complementary acoustic and linguistic features, to neural responses. Across cross-validated evaluations, individuals with schizophrenia showed numerically higher encoding alignment than matched controls across all evaluated regions of interest, although no effect survived false discovery rate correction in this small sample. The largest numerical group differences occurred in frontal language regions, including the middle frontal gyrus and dorsomedial prefrontal cortex, and in early auditory cortex. Subgroup analyses suggested that patients without auditory verbal hallucinations drove much of this numerical separation. These descriptive, hypothesis-generating findings suggest that model-based encoding can reveal a frontal-auditory signature in schizophrenia, but they do not establish a clinically actionable biomarker or preserved or enhanced speech encoding. Larger, adequately powered studies with richer feature spaces are needed for confirmatory inference and to test whether encoding-based measures can serve as clinically meaningful biomarkers.