title: A differential neural response in obsessive-compulsive disorder patients with washing compared with checking symptoms to disgust.
abstract: BACKGROUND
  Patients with obsessive-compulsive disorder (OCD) have symptoms that predominantly concern washing (washers) or checking (checkers), or both. Functional neuroimaging has been used to identify the neural correlates of the urge to ritualize but has not distinguished between washing and checking symptoms in OCD. We used functional magnetic resonance imaging to compare the neural response to emotive pictures in washers and checkers.
  
  
  METHODS
  In one of two 5-minute experiments, washers (N = 7), checkers (N = 7) and age-matched normal controls (N = 14) were scanned while viewing alternating blocks of normally disgusting (rated as disgusting by all subjects) and neutral pictures. In the other experiment, all patients and a normal subgroup (N = 8) viewed alternating blocks of washer-relevant (rated as more disgusting by washers than normal controls or checkers) and neutral pictures.
  
  
  RESULTS
  In all subjects, normally disgusting pictures activated visual regions implicated in perception of aversive stimuli and the insula, important in disgust perception. Only in washers were similar regions activated by washer-relevant pictures. In checkers, these pictures activated fronto-striatal regions associated with the urge to ritualize in OCD. Normal controls were more similar in neural response to checkers than washers to these pictures. Both normal controls and checkers had frontal regions activated significantly more by washer-relevant than normally disgusting pictures, and had these regions activated significantly more than washers by washer-relevant pictures.
  
  
  CONCLUSIONS
  We demonstrate a differential neural response to washer-relevant disgust in washers and checkers: only washers demonstrate a neural response to washer-relevant disgust associated with emotion perception rather than attention to non-emotive visual detail.
authors.affiliation: Department of Psychological Medicine, Institute of Psychiatry and GKT School of Medicine, University of London.
authors.forename: M L
authors.initials: ML
authors.lastname: Phillips
authors.forename: I M
authors.initials: IM
authors.lastname: Marks
authors.forename: C
authors.initials: C
authors.lastname: Senior
authors.forename: D
authors.initials: D
authors.lastname: Lythgoe
authors.forename: A M
authors.initials: AM
authors.lastname: O'Dwyer
authors.forename: O
authors.initials: O
authors.lastname: Meehan
authors.forename: S C
authors.initials: SC
authors.lastname: Williams
authors.forename: M J
authors.initials: MJ
authors.lastname: Brammer
authors.forename: E T
authors.initials: ET
authors.lastname: Bullmore
authors.forename: P K
authors.initials: PK
authors.lastname: McGuire
mesh_terms: D000293:Adolescent; D000328:Adult; D001143:Arousal / Q000502:physiology*; D001288:Attention / Q000502:physiology; D001931:Brain Mapping; D004644:Emotions / Q000502:physiology*; D005260:Female; D005625:Frontal Lobe / Q000503:physiopathology; D006235:Hand Disinfection; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D011939:Mental Recall / Q000502:physiology; D009042:Motivation; D009771:Obsessive-Compulsive Disorder / Q000175:diagnosis / Q000503:physiopathology* / Q000523:psychology; D009435:Synaptic Transmission / Q000502:physiology*; D014796:Visual Perception / Q000502:physiology