Lesions of inferior temporal (IT) cortex in humans can result in the syndrome termed prosopagnosia, an inability to recognize familiar faces. Single-cell recordings from IT cortex of monkeys have revealed the existence of neurons that are selectively activated by visual images of faces. Additionally, fMRI of both human and monkey brains has demonstrated face-selective regions, in which the fMRI signal evoked by faces is greater compared to that evoked by non-face objects. Together, these studies point to specialized neural machinery in the primate brain for processing faces. Thus far, our group and others have shown that the neural circuitry for face processing consists of a network of brain regions in the temporal and prefrontal cortex as well as in the amygdala. During the past year, we have made a number of important discoveries regarding the neural mechanisms mediating face processing: 1. Intranasal administration of oxytocin, a neuropeptide and potential treatment for autism, selectively altered behavioral responses to emotional expressions in monkeys, significantly reducing responses to both fearful and aggressive faces while leaving responses to appeasing and neutral faces unchanged, thereby explaining the beneficial effects of oxytocin on social cognition. 2. Unlike face-selective regions in the ventral stream, which all showed a contralateral visual field bias, those in the posterior superior temporal sulcus did not, indicating that these regions may form part of a anatomically distinct visual pathway that preferentially processes moving biological information such as facial expressions and human movement. 3. FMRI activation at 7T showed that the enhanced response to fearful relative to neutral faces in the primary visual cortex was confined to the superficial layers, consistent with the idea that the processing of facial valence in visual cortex is mediated through feedback projections from the amygdala. 4. Theta-burst transcranial magnetic stimulation (TBS) of the face-selective posterior superior temporal sulcus reduced resting-state fMRI functional connectivity across the face network, including face-selective areas on the ventral and medial surfaces, indicating that combined TBS/fMRI can be a useful method for mapping intrinsic brain network organization. 5. Granger causality analysis of MEG data revealed that, during configural face processing but not during featural face processing, dorsal stream visual areas send information to ventral stream visual areas, indicating that visuospatial information is transmitted from parietal cortex to ventral face-processing regions during configural face processing. 6. The results of an fMRI adaptation paradigm showed that changes in facial expression and changes in head orientation engage separate neural substrates within the superior temporal sulcus of macaques, indicating a division of labor within the network of brain regions specialized for processing faces. 7. Behavioral and fMRI results showed that individuals with Moebius Syndrome, a rare genetic disorder characterized by facial paralysis, leads to a specific impairment in processing facial expressions, such that their inability to produce facial expressions negatively impacts their perception of these expressions.