Neuronal Firing Rates and Patterns in the Globus Pallidus Internus of Patients With Cervical Dystonia Differ From Those With Parkinson's Disease

• Published in: Journal of neurophysiology Vol. 98; no. 2; pp. 720 - 729
• Main Authors: Tang, Joyce K. H, Moro, Elena, Mahant, Neil, Hutchison, William D, Lang, Anthony E, Lozano, Andres M, Dostrovsky, Jonathan O
• Format: Journal Article
• Language: English
• Published: United States Am Phys Soc 01.08.2007
• Subjects: Action Potentials - physiology; Adult; Aged; Analysis of Variance; Electric Stimulation - methods; Female; Globus Pallidus - pathology; Globus Pallidus - physiopathology; Humans; Male; Middle Aged; Neurons - physiology; Parkinson Disease - pathology; Parkinson Disease - physiopathology; Severity of Illness Index; Statistics, Nonparametric; Torticollis - pathology; Torticollis - physiopathology
• ISSN: 0022-3077; 1522-1598
• DOI: 10.1152/jn.01107.2006

1 Department of Physiology, University of Toronto; and 2 Movement Disorder Clinic and 3 Department of Neurosurgery, Toronto Western Hospital, Toronto, Canada Submitted 16 October 2006; accepted in final form 26 May 2007 Cervical dystonia (CD) is a movement disorder that involves involuntary turning and twisting of the neck caused by abnormal muscle contraction. Deep brain stimulation (DBS) in the globus pallidus internus (GPi) is used to treat both CD and the motor symptoms of Parkinson's disease (PD). It has been suggested that the differing motor symptoms in CD and PD may arise from a decreased GPi output in CD and elevation of output in PD. To test this hypothesis, extracellular recordings of GPi neuronal activity were obtained during stereotactic surgery for the implantation of DBS electrodes in seven idiopathic CD and 14 PD patients. The mean GPi neuronal firing rate recorded from CD patients was lower than that in PD patients ( P < 0.001; means ± SE: 71.4 ± 2.2 and 91.7 ± 3.0 Hz, respectively). Furthermore, GPi neurons fired in a more irregular pattern consisting of more frequent and longer pauses in CD compared with PD patients. When comparisons were done based on locations of recordings, these differences in firing rates and patterns were limited to the ventral portion of the GPi. In contrast, no difference in firing rate or pattern was observed in the globus pallidus externus between the two groups. These findings suggest that alterations in both firing rate and firing pattern may underlie the differing motor symptoms associated with these two movement disorders. Address for reprint requests and other correspondence: J. Dostrovsky, Dept. of Physiology, Medical Science Bldg. 3302, 1 King's College Circle, University of Toronto, Toronto, ON, Canada M5S 1A8 (E-mail: j.dostrovsky{at}utoronto.ca )