Microstimulation-Induced Inhibition of Neuronal Firing in Human Globus Pallidus

• Published in: Journal of neurophysiology Vol. 84; no. 1; pp. 570 - 574
• Main Authors: Dostrovsky, J. O, Levy, R, Wu, J. P, Hutchison, W. D, Tasker, R. R, Lozano, A. M
• Format: Journal Article
• Language: English
• Published: United States Am Phys Soc 01.07.2000
• Subjects: Action Potentials - physiology; Electric Stimulation; Globus Pallidus - physiology; Globus Pallidus - surgery; Humans; Microelectrodes; Neural Inhibition - physiology; Neurons - physiology; Parkinson Disease - physiopathology
• ISSN: 0022-3077; 1522-1598
• DOI: 10.1152/jn.2000.84.1.570

Departments of   1 Physiology and   2 Surgery, University of Toronto, Toronto, Ontario M5S 1A8, Canada Dostrovsky, J. O., R. Levy, J. P. Wu, W. D. Hutchison, R. R. Tasker, and A. M. Lozano. Microstimulation-Induced Inhibition of Neuronal Firing in Human Globus Pallidus. J. Neurophysiol. 84: 570-574, 2000. Neurosurgical treatment of Parkinson's disease (PD) frequently employs chronic high-frequency deep brain stimulation (DBS) within the internal segment of globus pallidus (GPi) and can very effectively reduce L-dopa-induced dyskinesias and bradykinesia, but the mechanisms are unknown. The present study examined the effects of microstimulation in GPi on the activity of neurons close to the stimulation site. Recordings were made from GPi using two fixed or independently controlled microelectrodes, with the electrode tips usually ~250 or >600 µm apart in PD patients undergoing stereotactic exploration to localize the optimal site for placement of a lesion or DBS electrode. The spontaneous activity of nearly all of the cells (22/23) recorded in GPi in three patients was inhibited by microstimulation at currents typically <10 µA (0.15-ms pulses at 5 Hz). The inhibition had a duration of 10-25 ms at threshold. These findings suggest that microstimulation within GPi preferentially excites the axon terminals of striatal and/or external pallidal neurons causing release of GABA and inhibition of GPi neurons.