Gender differences in electrophysiological responses to facial stimuli

Background: A facial discrimination task was adapted to be used in an event-related potential (ERP) paradigm in order to evaluate whether young women’s brain responses to affective stimuli differed from those of young men. Methods: The stimuli used to generate a late positive component of the ERP, designated the “P450,” were male and female faces with neutral, sad, or happy facial expressions. Subjects were instructed to respond to the happy and sad faces but not to the neutral faces. The amplitude and latency of the P450 component was evaluated with respect to the gender of the subject, as well as the gender and emotional affect of the facial stimuli themselves. Results: In all subjects, the sad faces elicited longer latency and higher amplitude P450 components as compared to the happy faces. Female subjects were found to generate significantly longer latency and higher amplitude P450 components than male subjects to both happy and sad faces. All subjects were found to respond more quickly to: male happy faces > female happy faces > female sad faces > male sad faces. Conclusions: These data suggest that the morphology of the late positive component of the ERP differs depending on the emotional expression of the stimuli, the gender of the facial stimulus, and the gender of the subject.