title: Modulation of Beta oscillations in the subthalamic nucleus with prosaccades and antisaccades in Parkinson's disease.
abstract: Increased oscillations in the beta band are thought to be related to motor symptoms of Parkinson's disease (PD). Previous studies have shown that beta-band desynchronization in the subthalamic nucleus (STN) is reduced just before and during limb movements. While the STN is part of the basal ganglia (BG)-thalamocortical circuit controlling limb movements, it is also part of the BG-brainstem projection controlling saccadic eye movements. Late-stage PD patients have deficits in saccades in addition to difficulties with limb movements arising from impaired functions of the BG. We investigated saccade-related changes in beta-band (15-30 Hz) oscillatory activities in the human STN while PD patients performed visually guided prosaccades and antisaccades, the latter requiring suppression of reflexive responses and volitional initiation of saccades. We recorded local field potentials from deep brain stimulation electrodes implanted in the STN in human PD patients 1-5 d after surgery and compared prosaccades and antisaccades with these and with limb movements. Saccade-related beta-band desynchronizations were observed just before and during saccades in all subjects, suggesting that reduction of beta-band oscillatory activity in the STN is related to preparation and execution of saccades. Furthermore, beta-band desynchronizations for antisaccades started earlier, were sustained for longer periods, were of greater magnitude, and were observed more often than prosaccades. Beta-band desynchronization in the STN may reflect the additional processes associated with suppression of reflexive responses and volitional execution of saccades in the opposite direction.
authors.affiliation: Division of Neurology, Toronto Western Research Institute, and the Edmond J. Safra Program in Parkinson's Disease, University of Toronto, Toronto, Ontario M5T 2S8, Canada. yugetaa-tky@umin.ac.jp
authors.forename: Akihiro
authors.initials: A
authors.lastname: Yugeta
authors.forename: William D
authors.initials: WD
authors.lastname: Hutchison
authors.forename: Clement
authors.initials: C
authors.lastname: Hamani
authors.forename: Utpal
authors.initials: U
authors.lastname: Saha
authors.forename: Andres M
authors.initials: AM
authors.lastname: Lozano
authors.forename: Mojgan
authors.initials: M
authors.lastname: Hodaie
authors.forename: Elena
authors.initials: E
authors.lastname: Moro
authors.forename: Bogdan
authors.initials: B
authors.lastname: Neagu
authors.forename: Robert
authors.initials: R
authors.lastname: Chen
mesh_terms: D000368:Aged; D001611:Beta Rhythm / Q000502:physiology*; D046690:Deep Brain Stimulation / Q000379:methods*; D004576:Electromyography; D004596:Electroretinography; D005071:Evoked Potentials / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015835:Ocular Motility Disorders / Q000209:etiology / Q000628:therapy*; D010300:Parkinson Disease / Q000150:complications / Q000628:therapy*; D011930:Reaction Time / Q000502:physiology; D012438:Saccades; D020531:Subthalamic Nucleus / Q000502:physiology*