Abstract

The reward generated by social interactions is critical for promoting prosocial behaviors. Here we present evidence that oxytocin (OXT) release in the ventral tegmental area (VTA), a key node of the brain’s reward circuitry, is necessary to elicit social reward. During social interactions, activity in paraventricular nucleus (PVN) OXT neurons increased. Direct activation of these neurons in the PVN or their terminals in the VTA enhanced prosocial behaviors. Conversely, inhibition of PVN OXT axon terminals in the VTA decreased social interactions. OXT increased excitatory drive onto reward-specific VTA dopamine (DA) neurons. These results demonstrate that OXT promotes prosocial behavior through direct effects on VTA DA neurons, thus providing mechanistic insight into how social interactions can generate rewarding experiences.

Brain circuits that modulate sociability

Understanding the neural mechanisms that mediate social reward has important societal and clinical implications. Hung et al. found that release of the neuropeptide oxytocin in the ventral tegmental area of the brain increased prosocial behaviors in mice (see the Perspective by Preston). Optogenetic manipulation of oxytocin release influenced sociability in a context-dependent manner. Oxytocin increased activity in dopamine cells that project to the nucleus accumbens, another key node of reward circuitry in the brain.