Patients with schizophrenia show response inhibition deficits equal to or greater than those seen in impulse-control disorders, and these deficits contribute to poor outcome. However, little is known about the circuit abnormalities underlying this impairment. To address this, we examined stop signal task performance in 21 patients with schizophrenia and 21 healthy controls using event related potential (ERP) and resting state functional connectivity. Patients showed prolonged stop signal reaction time (SSRT) and reduced N1, N2, and P3 amplitudes compared to controls. Across groups, P3 amplitudes were maximal after SSRT (i.e., after the time associated with the decision to stop occurred), suggesting that this component indexed response monitoring. Multiple regression analyses showed that longer SSRTs were independently related to 1) patient status, 2) reduced N1 amplitude on successful stop trials and 3) reduced anticorrelated resting state functional connectivity between visual and frontoparietal cortical networks. This study used a combined multimodal imaging approach to better understand the network abnormalities that underlie response inhibition in schizophrenia. It is the first of its kind to specifically assess the brain's resting state functional architecture in combination with behavioral and ERP methods to investigate response inhibition in schizophrenia.
Keywords: EEG; Impulsivity; Resting state functional connectivity; Schizophrenia; Stop signal task.