title: Neural responses to facial expressions of disgust but not fear are modulated by washing symptoms in OCD.
abstract: BACKGROUND
  Washing symptoms in Obsessive-Compulsive Disorder (OCD) are associated with increased trait sensitivity to disgust. This study explored neural systems underlying sensitivity to symptom-unrelated disgust and fear in OCD using functional neuroimaging.
  
  
  METHODS
  Seventeen OCD subjects and 19 controls viewed facial expressions of disgust and fear (versus neutral) presented just above the level of conscious awareness in a backward masking paradigm.
  
  
  RESULTS
  The OCD group showed greater activation than controls in the left ventrolateral prefrontal cortex, but reduced activation in the thalamus, to facial expressions of disgust. There were no between-group differences in response to fear. Further analysis using a median-split to divide OCD subjects into high and low washers suggested that the enhanced ventrolateral prefrontal cortex response was being driven by predominantly female OCD subjects with high washing symptoms. These subjects also reported higher levels of trait sensitivity to disgust.
  
  
  CONCLUSIONS
  These findings are consistent with previous reports of increased response to symptom-relevant and generally disgusting stimuli in neural regions associated with disgust and autonomic response processing in OCD patients with prominent washing symptoms. Together, these findings point to increased sensitivity to disgust stimuli as a component of the pathophysiology of the washing/contamination symptom dimension of OCD.
authors.affiliation: Division of Psychological Medicine, Section of Neuroscience & Emotion, King's College London, London, United Kingdom. n.lawrence@iop.kcl.ac.uk
authors.forename: Natalia S
authors.initials: NS
authors.lastname: Lawrence
authors.forename: Suk Kyoon
authors.initials: SK
authors.lastname: An
authors.forename: David
authors.initials: D
authors.lastname: Mataix-Cols
authors.forename: Florian
authors.initials: F
authors.lastname: Ruths
authors.forename: Anne
authors.initials: A
authors.lastname: Speckens
authors.forename: Mary L
authors.initials: ML
authors.lastname: Phillips
mesh_terms: D000328:Adult; D001921:Brain / Q000503:physiopathology; D001923:Brain Chemistry / Q000502:physiology; D019260:Expressed Emotion / Q000502:physiology*; D005149:Facial Expression; D005239:Fear / Q000502:physiology* / Q000523:psychology*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D009771:Obsessive-Compulsive Disorder / Q000503:physiopathology* / Q000523:psychology*; D010101:Oxygen Consumption / Q000502:physiology; D011569:Psychiatric Status Rating Scales