The Relationship between the Rhythmic Alpha Activity of the Subthalamic Nucleus and Motor Symptoms in Patients with Parkinson’s Disease

Increases in oscillatory β activity in the basal ganglia are regarded as one of the main electrophysiological biomarkers of impaired motor control in Parkinson’s disease. The functional role of dynamic changes in rhythmic activity during movement execution is still not fully understood. Microelectrode recording analysis addressed rhythmic neuronal activity in the subthalamic nucleus in nine patients with Parkinson’s disease during neurosurgical operations to implant deep brain stimulation systems. The results revealed a significant positive correlation between the amplitudes of α (7–12 Hz) and low β (12–20 Hz) activity in the subthalamic nucleus and evaluations of motor symptoms in patients with Parkinson’s disease. The amplitude of rhythmic α activity, in contrast to that of β rhythms, was also found to decrease significantly when patients performed motor tests. Moreover, the extent of decreases in α activity correlated directly with the severity of bradykinesia. The results obtained suggest that, along with β activity, the rhythmic α-activity of neurons in the subthalamic nucleus also plays a role in motor control in patients with Parkinson’s disease.