title: Excessive synchronization of basal ganglia neurons at 20 Hz slows movement in Parkinson's disease.
abstract: Excessive synchronization of neuronal activity at around 20 Hz is a common finding in the basal ganglia of patients with untreated Parkinson's disease (PD). Correlative evidence suggests, but does not prove, that this spontaneous activity may contribute to slowness of movement in this condition. Here we investigate whether externally imposed synchronization through direct stimulation of the region of the subthalamic nucleus at 20 Hz can slow motor performance in a simple unimanual tapping task and whether this effect is frequency selective. Tapping rates were recorded on 42 sides in 22 patients with PD after overnight withdrawal of medication. Tapping was performed without stimulation and during bilateral stimulation at 20 Hz, 50 Hz and 130 Hz. We found that tapping rates were slowed by 8.2+/-3.2% (p=0.014) during 20-Hz stimulation in subjects with relatively preserved baseline function in the task. This effect was frequency selective. The current data provide proof of the principle that excessive beta synchrony within the basal ganglia-cortical loop may contribute to the slowing of movements in Parkinson's disease.
authors.affiliation: Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, London, UK.
authors.forename: Chiung Chu
authors.initials: CC
authors.lastname: Chen
authors.forename: Vladimir
authors.initials: V
authors.lastname: Litvak
authors.forename: Thomas
authors.initials: T
authors.lastname: Gilbertson
authors.forename: Andrea
authors.initials: A
authors.lastname: Kühn
authors.forename: Chin Song
authors.initials: CS
authors.lastname: Lu
authors.forename: Shih Tseng
authors.initials: ST
authors.lastname: Lee
authors.forename: Chon Haw
authors.initials: CH
authors.lastname: Tsai
authors.forename: Stephen
authors.initials: S
authors.lastname: Tisch
authors.forename: Patricia
authors.initials: P
authors.lastname: Limousin
authors.forename: Marwan
authors.initials: M
authors.lastname: Hariz
authors.forename: Peter
authors.initials: P
authors.lastname: Brown
mesh_terms: D000368:Aged; D001479:Basal Ganglia / Q000503:physiopathology*; D004558:Electric Stimulation / Q000379:methods; D004594:Electrophysiology; D005260:Female; D005385:Fingers / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009068:Movement; D009474:Neurons; D010300:Parkinson Disease / Q000503:physiopathology*; D011930:Reaction Time; D020531:Subthalamic Nucleus / Q000503:physiopathology