Prefrontal cortex activity during response inhibition associated with excitement symptoms in schizophrenia.

Previous fMRI studies of schizophrenia have shown a prefrontal abnormality during response inhibition. However, the association with the clinical symptoms in schizophrenia remains unclear. The aim of the present study was to clarify the association of psychotic symptoms with the prefrontal function during response inhibition in patients with schizophrenia. We evaluated the prefrontal activity during the Go/NoGo task in 14 patients with schizophrenia and age- and gender-matched 40 healthy controls using multi-channel near-infrared spectroscopy. We also examined the relationship between the prefrontal function during the Go/NoGo task and psychotic symptoms assessed by the PANSS five-factor model in patients with schizophrenia. Subjects in both groups performed well on the task, and the omission and commission error rates in the NoGo condition showed no statistically significant differences. The comparison of prefrontal activation between the Go condition and the NoGo condition in each group revealed that the healthy controls had a significant deactivation during the NoGo condition in the dorsolateral prefrontal cortex (DLPFC), and such changes were not shown in patients with schizophrenia. Furthermore, in patients with schizophrenia, the excitement score of the PANSS five-factor model was positively correlated with the activation in the right prefrontal cortex and frontopolar region. These results suggested that the abnormal prefrontal activity during simple inhibition of response would be associated with excitement symptoms in patients with schizophrenia.