Faculty Bibliography

OBJECTIVE: The neuropeptide oxytocin is implicated in social processing, and recent research has begun to explore how gender relates to the reported effects. This study examined the effects of oxytocin on social affective perception and learning. METHODS: Forty-seven male and female participants made judgments of faces during two different tasks, after being randomized to either double-blinded intranasal oxytocin or placebo. In the first task, "unseen" affective stimuli were presented in a continuous flash suppression paradigm, and participants evaluated faces paired with these stimuli on dimensions of competence, trustworthiness, and warmth. In the second task, participants learned affective associations between neutral faces and affective acts through a gossip learning procedure and later made affective ratings of the faces. RESULTS: In both tasks, we found that gender moderated the effect of oxytocin, such that male participants in the oxytocin condition rated faces more negatively, compared with placebo. The opposite pattern of findings emerged for female participants: they rated faces more positively in the oxytocin condition, compared with placebo. CONCLUSIONS: These findings contribute to a small but growing body of research demonstrating differential effects of oxytocin in men and women.

BACKGROUND: Exaggerated amygdala and reduced ventromedial prefrontal cortex (vmPFC) responsiveness during emotional processing have been reported in studies examining individual anxiety disorders. Studies are needed, however, which directly compare activation of amygdalo-cortical circuitry across multiple anxiety disorders within the same study. Here we compared cortico-limbic neurocircuitry across three different anxiety disorders using a well-validated emotional probe task. METHODS: Sixty-five adult volunteers, including 22 healthy controls (HC) and participants meeting DSM-IV criteria for either posttraumatic stress disorder (14 PTSD), panic disorder (14 PD), or specific animal phobia (15 SP), underwent functional magnetic resonance imaging (fMRI) at 3 T while passively viewing backward-masked images of faces expressing fear, happy, and neutral emotions. RESULTS: A group comprising all three anxiety disorders showed greater activation within the left amygdala and reduced activation within the vmPFC compared to the HC group during the masked fear versus neutral condition. Pairwise group comparisons showed that amygdala activation only reached significance for the PTSD versus HCs, whereas decreased vmPFC was only evident for SP and PD groups versus the HC group. Furthermore, activation did not differ among the anxiety groups when contrasted directly with one another. A similar pattern was observed for masked happy versus neutral faces. CONCLUSIONS: Exclusive of specific diagnostic category, anxiety disorders were generally associated with increased activation of the amygdala and reduced activation within vmPFC. Categorical distinctions were generally weak or not observed and suggest that functional differences may reflect the magnitude of responses within a common neurocircuitry across disorders rather than activation of distinct systems.