title: Adaptive grip force is modulated by subthalamic beta activity in Parkinson's disease patients.
abstract: BACKGROUND
  Healthy subjects scale grip force to match the load defined by physical object properties such as weight, or dynamic properties such as inertia. Patients with Parkinson's disease (PD) show an elevated grip force in dynamic object handling, but temporal aspects of anticipatory grip force control are relatively preserved. In PD patients, beta frequency oscillatory activity in the basal ganglia is suppressed prior to externally paced movements. However, the role of the subthalamic nucleus (STN) in anticipatory grip force control is not known.
  
  
  METHODS
  After implantation of deep brain stimulation (DBS) electrodes in the STN, PD patients performed adaptive and voluntary grip force tasks, while we recorded subthalamic local field potentials (LFP) and scalp EEG.
  
  
  RESULTS
  During adaptive grip force control (Shake), we found event related desynchronization (ERD) in the beta frequency band, which was time-locked to the grip force. In contrast, during voluntary grip force control (Press) we recorded a biphasic ERD, corresponding to peak grip force and grip force release. Beta synchronization between STN and cortical EEG was reduced during adaptive grip force control.
  
  
  CONCLUSIONS
  The time-locked suppression of beta oscillatory activity in the STN is in line with previous reports of beta ERD prior to voluntary movements. Our results show that the STN is involved in anticipatory grip force control in PD patients. The difference in the phasic beta ERD between the two tasks and the reduction of cortico-subthalamic synchronization suggests that qualitatively different neuronal network states are involved in different grip force control tasks.
authors.affiliation: Department of Neurology, University Hospital Zurich, Frauenklinikstrasse 26, Zurich 8091, Switzerland ; University of Zurich, Zurich, Switzerland.
authors.forename: Lukas L
authors.initials: LL
authors.lastname: Imbach
authors.affiliation: Department of Neurology, University Hospital Zurich, Frauenklinikstrasse 26, Zurich 8091, Switzerland ; University of Zurich, Zurich, Switzerland.
authors.forename: Heide
authors.initials: H
authors.lastname: Baumann-Vogel
authors.affiliation: Department of Neurology, University Hospital Zurich, Frauenklinikstrasse 26, Zurich 8091, Switzerland ; Neuroscience Center, University of Zurich and ETH Zurich, Zurich, Switzerland ; University of Zurich, Zurich, Switzerland.
authors.forename: Christian R
authors.initials: CR
authors.lastname: Baumann
authors.affiliation: Department of Neurosurgery, University Hospital Zurich, Frauenklinikstrasse 10, Zurich 8091, Switzerland ; University of Zurich, Zurich, Switzerland.
authors.forename: Oguzkan
authors.initials: O
authors.lastname: Sürücü
authors.affiliation: Department of Sport and Health Sciences, Georg-Brauchle-Ring 60/62, Technische Universität München, München D-80992, Germany.
authors.forename: Joachim
authors.initials: J
authors.lastname: Hermsdörfer
authors.affiliation: Neuroscience Center, University of Zurich and ETH Zurich, Zurich, Switzerland ; Department of Neurosurgery, University Hospital Zurich, Frauenklinikstrasse 10, Zurich 8091, Switzerland ; University of Zurich, Zurich, Switzerland.
authors.forename: Johannes
authors.initials: J
authors.lastname: Sarnthein
mesh_terms: D000222:Adaptation, Physiological; D000368:Aged; D059031:Anticipation, Psychological / Q000502:physiology*; D001611:Beta Rhythm; D002540:Cerebral Cortex / Q000503:physiopathology; D046690:Deep Brain Stimulation; D004569:Electroencephalography; D005260:Female; D018737:Hand Strength; D006801:Humans; D008297:Male; D008875:Middle Aged; D009043:Motor Activity; D010300:Parkinson Disease / Q000503:physiopathology* / Q000628:therapy; D020531:Subthalamic Nucleus / Q000503:physiopathology*
keywords: Beta oscillations; DBS, deep brain stimulation; EEG; ERD, event related desynchronization; ERP, event related potentials; Motor control; PD, Parkinson's disease; STN, subthalamic nucleus; Subthalamic nucleus; Synchronization