AUTHOR=Li Xiaoyu , Zhuang Ping , Li Yongjie 

TITLE=Altered Neuronal Firing Pattern of the Basal Ganglia Nucleus Plays a Role in Levodopa-Induced Dyskinesia in Patients with Parkinson’s Disease

JOURNAL=Frontiers in Human Neuroscience

VOLUME=9

YEAR=2015

URL=https://www.frontiersin.org/journals/human-neuroscience/articles/10.3389/fnhum.2015.00630

DOI=10.3389/fnhum.2015.00630

ISSN=1662-5161

ABSTRACT=<p><bold>Background</bold>: Levodopa therapy alleviates the symptoms of Parkinson’s disease (PD), but long-term treatment often leads to motor complications such as levodopa-induced dyskinesia (LID).</p><p><bold>Aim</bold>: To explore the neuronal activity in the basal ganglia nuclei in patients with PD and LID.</p><p><bold>Methods</bold>: Thirty patients with idiopathic PD (age, 55.1 ± 11.0 years; disease duration, 8.7 ± 5.6 years) were enrolled between August 2006 and August 2013 at the Xuanwu Hospital, Capital Medical University, China. Their Hoehn and Yahr (<xref ref-type="bibr" rid="B16">1967</xref>) scores ranged from 2–4 and their UPDRS III scores were 28.5 ± 5.2. Fifteen of them had severe LID (UPDRS IV scores of 6.7 ± 1.6). Microelectrode recording was performed in the globus pallidus internus (GPi) and subthalamic nucleus (STN) during pallidotomy (<italic>n</italic> = 12) or STN deep brain stimulation (DBS; bilateral, <italic>n</italic> = 12; unilateral, <italic>n</italic> = 6). The firing patterns and frequencies of various cell types were analyzed by assessing single cell interspike intervals (ISIs) and the corresponding coefficient of variation (CV).</p><p><bold>Results</bold>: A total of 295 neurons were identified from the GPi (<italic>n</italic> = 12) and STN (<italic>n</italic> = 18). These included 26 (8.8%) highly grouped discharge, 30 (10.2%) low frequency firing, 78 (26.4%) rapid tonic discharge, 103 (34.9%) irregular activity, and 58 (19.7%) tremor-related activity. There were significant differences between the two groups (<italic>p</italic> &lt; 0.05) for neurons with irregular firing, highly irregular cluster-like firing, and low-frequency firing.</p><p><bold>Conclusion</bold>: Altered neuronal activity was observed in the basal ganglia nucleus of GPi and STN, and may play important roles in the pathophysiology of PD and LID.</p>