In terms of brain activity, we found that movement-related PAC in the pressing task was persistently enhanced in patients compared with controls. This was the case in four cortical areas, all involved in motor control, namely PMC, M1, BA3, and BA1&2. By contrast, we found no differences in the movement-related PAC level between patients and controls in the repetitive tapping tasks, despite the abnormal motor behavior of patients. These results suggest that abnormal enhancement of state-related PAC in movement states is neither necessary nor sufficient for Parkinsonian motor impairment and, therefore, not directly related to the motor symptoms. In addition, our finding that state-related PAC was more strongly suppressed during movements in patients than in controls is consistent with previous suggestions (17) that enhanced resting PAC in patients with PD may return to normal during the movement.
