Figure 4.

OCD patient. Intraoperative recordings. Shown are averaged ERPs from the surface (Cz – A1) and from the depth electrode within the Nacc or 5 mm above the target. Button press errors (25% of trials) show a typical error-related negativity with a maximum at about 70 ms at Cz. By contrast correct trials show a positive deflection. Clearly, activity from the Nacc proper but not from the region 5 mm above the target shows error-related modulations. To rule out the possibility that differences in brain responses are due to differences in reaction times in error and correct trials, correct trials matched to the error trials with regard to RT are also shown.