Oxytocinergic modulation of brain activation to cues related to reproduction and attachment: Differences and commonalities during the perception of erotic and fearful social scenes.

In animal research, the neuropeptide oxytocin (OT) has been known for its role in reproduction and attachment for a longer time. There is strong evidence for an involvement of the mesolimbic dopaminergic system for these effects of OT. In contrast, human research rather concentrated on more human concepts of social cognition and behavior (e.g. trust or processing of fearful faces) and mainly focused on the amygdala as the main neurobiological substrate. To extend this view, we wanted to gain more insight into the neurobiological effects of OT in the context of reproduction and attachment in humans and compare these effects to its well-known effects on fear processing. In a double-blind placebo-controlled fMRI study, we investigated 55 healthy young men using intranasal OT administration. During fMRI, participants saw attachment-related erotic scenes and fearful social scenes. Over all participants, OT had a differential effect on processing of erotic and fearful scenes. While OT administration led to a relative increase of neural activation in mesolimbic structures during processing of erotic stimuli, it decreased amygdala activation for fearful stimuli. On the individual level, we observed significant positive correlations between OT induced activation changes across different brain regions and under different stimulus conditions. Our findings extend the already existing animal literature and provide evidence for a similar involvement of the mesolimbic dopaminergic system for OT effects in the context of reproduction and attachment in humans.