title: Neuronal correlates of obsessions in the caudate nucleus.
abstract: BACKGROUND
  Metabolic overactivity of corticosubcortical loops including the caudate nucleus (CN) has been reported in obsessive-compulsive disorder (OCD) using functional imaging techniques. However, direct proof of a modification of neuronal activity within the CN of OCD patients is still lacking. We tested the hypothesis that obsessions or compulsions might be associated with particular features of neuronal activity in the CN of OCD patients.
  
  
  METHODS
  Single unit recordings were performed peroperatively in the CN of three patients with severe forms of obsessive-compulsive disorder (OCD) who were candidates for deep brain stimulation of the CN. Severity of obsessions was assessed preoperatively with the Yale-Brown Obsessive Compulsive Scale (Y-BOCS) and peroperatively with a subjective obsession score based on a visual analog scale (VAS).
  
  
  RESULTS
  Frequency of CN discharge and variability of interspike intervals were found to be abnormally high in two patients with a high VAS score during surgery but not in one with a low VAS score. Lateralization and depth of recording influenced neuronal activity variably among patients.
  
  
  CONCLUSIONS
  Because the three patients had high Y-BOCS scores before surgery, these findings suggest that caudate hyperactivity in OCD is concomitant with the occurrence of the obsession process.
authors.affiliation: Department of Clinical Neurophysiology, CHU de Bordeaux, Place Amélie Rabat-Léon, Centre National de Recherche Scientifique Unité Mixte de Recherche 5543, Université Victor Segalen, Bordeaux, France.
authors.forename: Dominique
authors.initials: D
authors.lastname: Guehl
authors.forename: Abdelhamid
authors.initials: A
authors.lastname: Benazzouz
authors.forename: Bruno
authors.initials: B
authors.lastname: Aouizerate
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Cuny
authors.forename: Jean-Yves
authors.initials: JY
authors.lastname: Rotgé
authors.forename: Alain
authors.initials: A
authors.lastname: Rougier
authors.forename: Jean
authors.initials: J
authors.lastname: Tignol
authors.forename: Bernard
authors.initials: B
authors.lastname: Bioulac
authors.forename: Pierre
authors.initials: P
authors.lastname: Burbaud
mesh_terms: D001931:Brain Mapping; D002421:Caudate Nucleus / Q000503:physiopathology*; D002540:Cerebral Cortex / Q000503:physiopathology; D046690:Deep Brain Stimulation; D004292:Dominance, Cerebral / Q000502:physiology; D004569:Electroencephalography; D005071:Evoked Potentials / Q000502:physiology; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009415:Nerve Net / Q000503:physiopathology; D009474:Neurons / Q000502:physiology; D009714:Nucleus Accumbens / Q000503:physiopathology; D009771:Obsessive-Compulsive Disorder / Q000175:diagnosis / Q000503:physiopathology* / Q000628:therapy; D009435:Synaptic Transmission / Q000502:physiology*