Oxytocin neural responses distinguish social novelty from familiarity but not kin from non-kin in male spiny mice.

In most species, individuals must be able to identify threats, peers, and potential mates to survive. The distinction of kin from non-kin and novel conspecifics from familiars is essential to the successful categorization of these identities. Although oxytocin (OXT) signaling has been implicated in social recognition, little is known about the contributions of distinct OXT-producing cell groups to distinguishing conspecific type. To determine whether OXT-producing neuronal populations differentially respond to novelty or kinship status, we conducted immediate early gene tests in male spiny mice (Acomys dimidiatus), a communally breeding species that we previously showed distinguishes between novelty and kinship status. Immunohistochemical analysis of brain tissue revealed that the OXT cell populations in the paraventricular nucleus of the hypothalamus and the anterior hypothalamus did not differentially respond to the kinship or novelty status of same-sex conspecifics. However, while OXT-producing neurons in the bed nucleus of the stria terminalis did not distinguish between kin and non-kin spiny mice, this cell group was more responsive to familiar than novel conspecifics. These results suggest that extrahypothalamic OXT neurons may be involved in aspects of processing the novelty status of a conspecific.