Static and dynamic brain region activation abnormalities in schizophrenia: Evidence from fNIRS

Schizophrenia (SZ) is characterized by marked cognitive impairments and substantial clinical heterogeneity. The temporal variability of brain activity may contribute to its complex symptoms, but remains poorly understood. This study examined static and dynamic brain region activation (BRA) using functional near-infrared spectroscopy (fNIRS) to identify neural alterations in SZ and explore their clinical relevance.

Forty-four SZ patients and 36 healthy controls were recruited and completed fNIRS during a verbal fluency task. Cognition and symptoms were assessed using the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) and Positive and Negative Syndrome Scale (PANSS). Static BRA was calculated from time-averaged activation, while dynamic BRA was derived using sliding-window and principal component analyses. Correlations and regressions examined relationships between BRA and clinical measures.

SZ patients showed nominally increased static BRA in the right prefrontal cortex (RPFC) and premotor cortex (RPMC) at the uncorrected level. Dynamic analysis revealed reduced PC1-derived BRA in the right medial prefrontal cortex, right occipital lobe (ROL), and RPMC (all p-FDR < 0.05). Several dynamic BRA were associated with clinical symptoms and cognitive function. Regression models confirmed that RPFC activation contributed to general psychopathology scores (β = -0.476, p-FDR = 0.017) and PANSS total scores (β = -0.534, p-FDR = 0.009). Regarding cognition, left supplementary motor area activation contributed to language scores (β = -0.502, p-FDR = 0.012), and ROL activation contributed to visuospatial/constructional scores (β = -0.378, p-FDR = 0.033).

SZ involves both altered overall activation and abnormal dynamic hemodynamic responses during verbal fluency.