title: Subthalamic neuronal firing in obsessive-compulsive disorder and Parkinson disease.
abstract: OBJECTIVE
  Although electrophysiologic dysfunction of the subthalamic nucleus is putative, deep brain stimulation of this structure has recently been reported to improve obsessions and compulsions. In Parkinson disease, sensorimotor subthalamic neurons display high-frequency burst firing, which is considered as an electrophysiologic signature of motor loop dysfunction. We addressed whether such neuronal dysfunction of the subthalamic nucleus also exists in the nonmotor loops involved in patients with obsessive-compulsive disorder.
  
  
  METHODS
  We compared the neuronal activity of the subthalamic nucleus recorded in 9 patients with obsessive-compulsive disorder with that of 11 patients with Parkinson disease measured during intraoperative exploration for deep brain stimulation.
  
  
  RESULTS
  The mean subthalamic neuron discharge rate was statistically lower in patients with obsessive-compulsive disorder than in patients with Parkinson disease (20.5 ± 11.0 Hz, n = 100 and 30.8 ± 15.6 Hz, n = 93, respectively, p < 0.001). The relative proportion of burst neurons did not differ significantly between the 2 diseases (75% vs 73%). Interestingly, burst neurons were predominantly left-sided in obsessive-compulsive disorder.
  
  
  CONCLUSIONS
  The recording of burst neurons within the nonmotor subthalamic nucleus in patients with obsessive-compulsive disorder is a novel finding that suggests the existence of deregulation of the nonmotor basal ganglia loop, possibly left-sided. Potentially, burst activity might interfere with normal processes occurring within nonmotor loops.
authors.affiliation: Grenoble University, France.
authors.forename: Brigitte
authors.initials: B
authors.lastname: Piallat
authors.forename: Mircea
authors.initials: M
authors.lastname: Polosan
authors.forename: Valérie
authors.initials: V
authors.lastname: Fraix
authors.forename: Laurent
authors.initials: L
authors.lastname: Goetz
authors.forename: Olivier
authors.initials: O
authors.lastname: David
authors.forename: Albert
authors.initials: A
authors.lastname: Fenoy
authors.forename: Napoleon
authors.initials: N
authors.lastname: Torres
authors.forename: Jean-Louis
authors.initials: JL
authors.lastname: Quesada
authors.forename: Eric
authors.initials: E
authors.lastname: Seigneuret
authors.forename: Pierre
authors.initials: P
authors.lastname: Pollak
authors.forename: Paul
authors.initials: P
authors.lastname: Krack
authors.forename: Thierry
authors.initials: T
authors.lastname: Bougerol
authors.forename: Alim L
authors.initials: AL
authors.lastname: Benabid
authors.forename: Stéphan
authors.initials: S
authors.lastname: Chabardès
mesh_terms: D000200:Action Potentials / Q000502:physiology*; D000328:Adult; D000368:Aged; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D009474:Neurons / Q000502:physiology*; D009771:Obsessive-Compulsive Disorder / Q000473:pathology*; D010300:Parkinson Disease / Q000473:pathology*; D020531:Subthalamic Nucleus / Q000473:pathology*