The Neuroendocrine and Cardiovascular Responses to a Pup in Male Prairie Voles (M. ochrogaster)

The neurobiology of alloparental care and neuroendocrine regulation of the autonomic nervous system were both investigated in male prairie voles (Microtus ochrogaster). The activity of the autonomic nervous system underlies mammalian social approach, and here we have shown that alloparental care in male voles is accompanied by an unexpected and sustained increase in heart rate in response to presentation with a pup. Adult male voles readily care for unfamiliar pups and do so with a diminishment of stress-related hormones and behaviors, while simultaneously experiencing a dramatic increase in the activity of the sympathetic nervous system. This increase in sympathetic activity does not habituate, but its expression does require a direct physical contact with a newborn pup. The neuropeptide oxytocin is critical for the expression of alloparental behavior, as blockade of the oxytocin receptor reduces males’ care for pups. Oxytocin is also involved in achieving the autonomic state male voles experience during alloparental care. Alloparental care is a fundamental aspect of human social behavior and understanding its neurobiology is critical towards future efforts at elucidating the etiology of alloparental dysfunction, which places children at risk.