Decreased Broca-Left Supplementary Motor Area Connectivity underlying Auditory Verbal Hallucination: A Resting-State NIRS Study

Background: Despite decades of research, the underlying mechanism of auditory verbal hallucinations (AVH), a core symptom of schizophrenia, is still unrevealed. Previous studies have tried to capture the neural activity during AVH episodes while the trait features of AVH were less investigated. To address this gap, we employed a resting-state functional Near Infrared Spectroscopy (fNIRS) to investigate the neuroimaging patterns in schizophrenia patients with AVH history (AVHh+). We hypothesized that significant differences of network activity modality may be observed in AVHh+. Method: We recruited 23 AVHh+, 16 schizophrenia patients without AVH history (AVHh-), and 17 matched healthy controls (HCs). Participants underwent an 8-minute resting-state fNIRS scanning. Data processing and analysis were conducted by the NirSpark software (HuiChuang, China) package and R Studio. Result: A significant lower bilateral functional connectivity (FC) strength in a range of frontal-temporal regions was observed in schizophrenic patients. Compared to the AVHh- group, the AVHh+ group showed significantly lower FC in the Broca's area and the left supplementary motor area (SMA). Conclusion: Schizophrenia demonstrated a widespread reduced FC in frontal and temporal regions. The hypoconnectivity of Broca-left SMA circuit might serve as a trait marker specific to AVH.