Pain-Induced Beta Activity in the Subthalamic Nucleus of Parkinson's Disease.

BACKGROUND: The subthalamic nucleus (STN) is a common target for deep brain stimulation (DBS) in Parkinson's disease (PD) and is believed to serve a role in sensorimotor integration. In addition to therapeutic neuromodulation, DBS facilitates the recording of local-field potentials (LFPs) in order to further understand the neurophysiological basis of disease. The capacity to wirelessly transmit these signals in real time has overcome the obstacle of externalization of electrodes during LFP recordings. OBJECTIVE: Using the G102RS device (PINS Medical, China), we investigated the LFP changes in response to mechanical pain stimulation to further elucidate the representation of pain sensation in the basal ganglia. METHODS: LFPs from 2 patients who had undergone bilateral STN-DBS were wirelessly recorded during no stimulation, low-frequency stimulation (60 and 90 Hz), and high-frequency stimulation (130 and 150 Hz) while introducing painful and nonpainful stimuli. Power spectral analysis was conducted to compare the changes in β frequency (13-30 Hz) during each stimulus. RESULTS: During painful stimuli, STN power spectra (n = 4) revealed a significant increase in β activity compared to non-painful and no-stimulus epochs. Both low- and high-frequency stimulation produced a significant decrease in pain-related β activity. CONCLUSION: These 2 cases have demonstrated the potential for acute noxious stimuli to exacerbate pathologic β oscillatory activity in the STN. Our findings represent novel evidence of the neurophysiologic representation of pain in the STN of PD patients.