The neurobiology of social bonds.

When released in the brain through giving birth or mating, the neuropeptides oxytocin and vasopressin are involved in promoting parent-offspring and monogamous bonds in animals such as sheep and voles. Bonds are only formed in species where receptors for these neuropeptides are highly expressed in dopamine-producing reward centres. In humans, dysfunctions in these same systems can be associated with autism and, when we see people we love, these systems become activated.