Sex Differences in Neural Activation to Ambiguous Facial Expression in Happy and Sad Context

Functional magnetic resonance imaging (fMRI) was used to investigate brain activation associated with a facial expression identification task (stimuli were full emotional, half emotional, or ambiguous in both happy and sad context) in 10 men and 10 women. fMRI assessment revealed significant interaction of sex × context in the right putamen for the ambiguous faces. Women showed a greater BOLD response to ambiguous facial expression in the sad context than in the happy context, while men showed a greater response in the happy context. Further, women showed a greater BOLD response than did men to ambiguous facial expression in the sad context, while men showed a greater response than women in the happy context. These results suggest that sad and happy context differentially modulate right putamen activation related to processing of ambiguous facial expression in men and women.