Neural responses to facial expressions of disgust but not fear are modulated by washing symptoms in OCD.
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.
Lawrence
Natalia S
NS
Division of Psychological Medicine, Section of Neuroscience & Emotion, King's College London, London, United Kingdom. n.lawrence@iop.kcl.ac.uk
An
Suk Kyoon
SK
Mataix-Cols
David
D
Ruths
Florian
F
Speckens
Anne
A
Phillips
Mary L
ML
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