Oxytocin has been called the 'love hormone' because it plays an important role in social behaviors, such as maternal care and pair bonding. In a new study researchers uncover oxytocin-responsive brain cells that are necessary for female social interest in male mice during estrus -- the sexually receptive phase of their cycle. These neurons, found in the prefrontal cortex, may play a role in other oxytocin-related social behaviors such as intimacy, love, or mother-child bonding.