Overactive performance monitoring in obsessive-compulsive disorder: ERP evidence from correct and erroneous reactions.

Obsessive-compulsive disorder (OCD) has repeatedly been associated with hyperactivity in fronto-striatal brain regions and regions related to performance monitoring. The aim of the current study was to further investigate electrophysiological correlates of performance monitoring. Specifically, we intended to replicate previous results revealing enhanced error-related negativity (ERN) amplitudes in OCD patients. Furthermore, we examined whether OCD patients also showed alterations regarding the correct-related negativity (CRN), the error positivity (Pe) and behavioural correlates of performance monitoring. Event-related brain potentials (ERPs) were recorded from a group of 20 OCD patients and 20 healthy control participants during a modified flanker task. Force sensitive response buttons were utilized to separate correct trials from incorrect trials with full and partial response activation. Both groups displayed substantial ERN and Pe amplitudes for full and partial errors. On error trials OCD patients showed enhanced ERN amplitudes, but group differences were not significant for the Pe and for behavioural adjustment. Further, the OCD group also exhibited enhanced CRN amplitudes and a correlation of frontal CRN amplitudes with symptom severity. These data provide further support for the view that performance monitoring is overactive in OCD. Further, since the amplitude enhancement is not specific to error processing, but is also observed for correct reactions, a response monitoring or evaluation process that contributes to both ERP components might be overactive in OCD. This is in line with fMRI results that revealed higher error- and conflict-related activity in the medial frontal cortex in OCD patients.