Galanin neurons in the brain's medial preoptic area that appear to regulate parental behavior, a mouse study finds. If similar neurons are at work in humans, it could offer clues to the treatment of conditions like post-partum depression. "If you look across different animal species, there are some species in which the father contributes to caring for the young -- sometimes the work is divided equally, sometimes the father does most of the work -- and there are species in which the father does nothing," a researcher said. "The essential question is where is that variability coming from? We may be tempted to say that the mom has the neurons required to engage in parental behavior, and dads don't -- this paper shows that's wrong."