title: High functional connectivity of tremor related subthalamic neurons in Parkinson's disease.
abstract: OBJECTIVE
  Tremor is a core symptom of Parkinson's disease (PD). The subthalamic nucleus (STN) seems to be crucial for tremor pathophysiology considering that deep brain stimulation (DBS) of the STN leads to an effective reduction of Parkinsonian tremor. Here, we investigate the functional connectivity between STN neurons in patients with Parkinsonian tremor.
  
  
  METHODS
  STN activity was analyzed in 7 patients with Parkinsonian rest tremor who underwent stereotactic surgery for DBS. Spike activity was registered in different depths of the STN using an array of five microelectrodes. Interneuronal coherence within the STN was analyzed.
  
  
  RESULTS
  Significant interneuronal coherence at the tremor frequency was detected in 78 out of 145 neurons. In contrast, interneuronal coherence in the beta band occurred only in 26 out of 145 neurons. Functional connectivity at the tremor frequency can be characterized by a slowly decaying exponential curve which describes coherence between STN neurons as a function of interneuronal distances between 0 and 4mm.
  
  
  CONCLUSIONS
  Spatially distributed synchronization at the tremor frequency seems to be a key feature of STN pathophysiology in patients with Parkinsonian tremor.
  
  
  CONCLUSIONS
  The findings suggest a subthalamic tremor network which is widely extended and strongly coupled.
authors.affiliation: Department of Neurology and Neurophysiology, University of Freiburg, Germany. florian.amtage@uniklinik-freiburg.de
authors.forename: Florian
authors.initials: F
authors.lastname: Amtage
authors.forename: Kathrin
authors.initials: K
authors.lastname: Henschel
authors.forename: Björn
authors.initials: B
authors.lastname: Schelter
authors.forename: Jan
authors.initials: J
authors.lastname: Vesper
authors.forename: Jens
authors.initials: J
authors.lastname: Timmer
authors.forename: Carl Hermann
authors.initials: CH
authors.lastname: Lücking
authors.forename: Bernhard
authors.initials: B
authors.lastname: Hellwig
mesh_terms: D000328:Adult; D017668:Age of Onset; D000368:Aged; D003627:Data Interpretation, Statistical; D046690:Deep Brain Stimulation; D004567:Electrodes, Implanted; D005260:Female; D006801:Humans; D007395:Interneurons / Q000502:physiology*; D008279:Magnetic Resonance Imaging; D008297:Male; D008839:Microelectrodes; D008875:Middle Aged; D009474:Neurons / Q000502:physiology*; D010300:Parkinson Disease / Q000503:physiopathology*; D013238:Stereotaxic Techniques; D020531:Subthalamic Nucleus / Q000166:cytology / Q000503:physiopathology*; D014202:Tremor / Q000503:physiopathology*