Vasopressin modulates neural responses related to emotional stimuli in the right amygdala.

The neuropeptide vasopressin has been shown to modulate social and affective processes. Using fMRI we investigated the influence of intranasal vasopressin (AVP) on neural activations related to social cognitions and emotion processing in a group of healthy young men. In a double-blind, placebo controlled between groups design, 20 IU AVP were administered intranasally to half of the participants before scanning, while the other half received saline intranasally. All participants viewed line drawings depicting either one or two persons (social factor) in an emotionally neutral or negative scene (emotional factor). Vasopressin modulated the activation of the right amygdala related to the emotional component of empathy. Moreover, vasopressin also increased connectivity of the right amygdala with the medial prefrontal cortex (mPFC) and the inferior parietal lobule during the processing of pictures illustrating a socially threatening scene. This suggests that AVP reduces suppressive effects of the mPFC on amygdala activity resulting in the observed enhanced neural pattern in the amygdala. At present, it remains unclear whether the increased amygdala activity reflects a direct impact of AVP on vasopressin V1 receptors in the amygdala or an indirect effect via vasopressin V1 receptors in the mPFC or other remote brain sites.