Neural correlates of error-related brain activity in obsessive-compulsive disorder

Abstract

Patients with obsessive–compulsive disorder (OCD) typically view perceived inadequacy or error in daily activities and often feel that compensatory action is needed to rid themselves of this perception. Enhanced error monitoring provides evidence for the fronto-striatal model of OCD, typically examined by measuring error-related negativity (ERN). This study examined ERN in OCD patients and compared it with that in healthy subjects through affective modulation induced by task-irrelevant emotional stimuli (fearful faces). A modified version of the flanker task with task-irrelevant emotional face stimuli was performed by 22 OCD patients and 22 healthy subjects while EEG signals were recorded from 65 electrodes. To quantify response-locked ERN, a mean amplitude of 20–120 msec post-response was computed. During trials with fearful face stimuli, the patients with OCD showed more significantly enhanced ERN amplitude than did the control. The difference between ERN following fearful and neutral face stimuli was larger in the OCD patients than in the control group. Across the entire sample, ERN following fearful and neutral face stimuli was reversely correlated with the responsibility subscore of the Dimensional Obsessive–Compulsive Scale. Only the OCD patients exhibited significantly increased ERN amplitude under fearful face conditions compared with neutral face conditions. The ERN amplitude of the healthy control did not vary with emotional interference. The OCD patients exhibited significantly larger and correct-related negativity amplitudes than did the control in both fearful and neutral conditions. These data provide further support for the view that performance monitoring is overactive in OCD. These findings also suggest that emotional interference using emotionally valent facial images modulates performance monitoring processes in OCD. On the basis of ERN as a state affect-independent property, changes in performance monitoring associated with emotional interference suggest that affective function in the fronto-striatal network be considered in understanding the neural bases of OCD.