Abstract
Over a lifetime, humans build relationships with family, friends, and partners that are critically important for our mental and physical health. Unlike commonly used laboratory mice and rats, Microtine rodents provide a unique model to study the neurobiology underlying pair bonding and the selective attachments that form between adults. Comparisons between monogamous prairie voles and the closely related but nonmonogamous meadow and montane voles have revealed that brain-region-specific neuropeptide receptor patterning modulates social behavior between and within species. In particular, diversity in vasopressin 1a receptor (V1aR) distribution has been linked to individual and species differences in monogamy-related behaviors such as partner preference, mate guarding, and space use. Given the importance of differential receptor expression for regulating social behavior, a critical question has emerged: What are the genetic and epigenetic mechanisms that underlie brain-region-specific receptor patterns? This review will summarize what is known about how the vasopressin (AVP)-V1aR axis regulates social behaviors via signaling in discrete brain regions. From this work, we propose that brain-region-specific regulatory mechanisms facilitate robust evolvability of V1aR expression to generate diverse sociobehavioral traits. Translationally, we provide a perspective on how these studies have contributed to our understanding of human social behaviors and how brain-region-specific regulatory mechanisms might be harnessed for targeted therapies to treat social deficits in psychiatric disorders such as depression, complicated grief, and autism spectrum disorder.