Abstract
Face perception is mediated by a distributed neural system in the human brain, but conventional univariate fMRI data analysis has not clearly localized differential responses to male as compared with female faces within this network. We used fMRI and multivariate pattern decoding to test whether we could detect gender-specific neural responses in forty subjects (hetero- and homosexual men and women), who viewed male and female faces and rated their attractiveness. Face stimuli evoked activation in the inferior occipital gyrus (IOG), fusiform gyrus (FG), superior temporal sulcus (STS), amygdala, inferior frontal gyrus (IFG), insula, and orbitofrontal cortex (OFC). Pattern classification with a sparse logistic regression algorithm revealed successful decoding of gender information with above chance accuracies within the IOG, FG, STS, IFG, INS and OFC, but not in the amygdala. We did not find any differences in decoding the gender of face stimuli (male vs. female) as a function of the subject's gender (men vs. women) or their sexual orientation (hetero- vs. homosexual). Our findings suggest that gender information is widely distributed across the face network and is represented in the “core” regions that process invariant facial features, as well as the “extended” regions that process changeable aspects of faces. The lack of gender-specific information in the amygdala is likely due to its role in threat detection and emotional processing.