Montane and prairie voles differ both in V1a-receptor binding pattern and behavioral response to arginine vasopressin (AVP).

Receptor autoradiography illustrates the different patterns of V_1a-receptor binding in the brains of a) the nonmonogamous montane vole, and b) the monogamous prairie vole. Note the high intensity of binding in the lateral septum (LS) of the montane vole but not the prairie vole and in the diagonal band (DB) of the prairie vole but not the montane vole. Similar differences exist throughout the brain. c) Male prairie but not montane voles exhibit elevated levels of affiliative behavior after AVP is administered directly into the brain. The affiliative behaviors following injection of AVP in each group of voles were compared to controls injected with artificial cerebrospinal fluid (CSF).