Sex differences in neural responses to disgusting visual stimuli: implications for disgust-related psychiatric disorders.
BACKGROUND
A majority of patients with disgust-related psychiatric disorders such as animal phobias and contamination-related obsessive-compulsive disorder are women. The aim of this functional magnetic resonance imaging (fMRI) study was to examine possible sex differences in neural responses to disgust-inducing stimuli that might help explain this female predominance.


METHODS
Thirty-four healthy adult volunteers (17 women, all right-handed) were scanned while viewing alternating blocks of disgusting and neutral pictures from the International Affective Picture System. Using a partially-silent fMRI sequence, the participants rated their level of discomfort after each block of pictures. Skin conductance responses (SCR) were measured throughout the experiment. All participants completed the Disgust Scale.


RESULTS
Both women and men reported greater subjective discomfort and showed more SCR fluctuations during the disgusting picture blocks than during the neutral picture blocks. Women and men also demonstrated a similar pattern of brain response to disgusting compared with neutral pictures, showing activation in the anterior insula, ventrolateral and dorsolateral prefrontal cortices, and visual regions. Compared with men, women had significantly higher disgust sensitivity scores, experienced more subjective discomfort, and demonstrated greater activity in left ventrolateral prefrontal regions. However, these differences were no longer significant when disgust sensitivity scores were controlled for.


CONCLUSIONS
In healthy adult volunteers, there are significant sex-related differences in brain responses to disgusting stimuli that are irrevocably linked to greater disgust sensitivity scores in women. The implications for disgust-related psychiatric disorders are discussed.
Caseras
Xavier
X
Department of Psychological Medicine, King's College London, Institute of Psychiatry, United Kingdom.
Mataix-Cols
David
D
An
Suk Kyoon
SK
Lawrence
Natalia S
NS
Speckens
Anne
A
Giampietro
Vincent
V
Brammer
Michael J
MJ
Phillips
Mary L
ML
D000293:Adolescent; D000328:Adult; D001921:Brain / Q000098:blood supply / Q000502:physiology*; D001931:Brain Mapping; D004192:Discrimination, Psychological / Q000502:physiology*; D004644:Emotions / Q000502:physiology*; D005260:Female; D005712:Galvanic Skin Response; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D001523:Mental Disorders / Q000175:diagnosis / Q000503:physiopathology; D008875:Middle Aged; D010100:Oxygen / Q000097:blood; D010364:Pattern Recognition, Visual / Q000502:physiology; D010775:Photic Stimulation / Q000379:methods; D011569:Psychiatric Status Rating Scales; D012016:Reference Values; D012727:Sex Characteristics
D010100:Oxygen