Neural basis of aggressive behavior toward newborns in Mice: Advances and future Challenges

Infanticidal or pup-directed aggressive behavior is present in most species, including humans. It occurs in both reproductive and non-reproductive contexts and its incidence and biological basis may vary among species, strains, sex, and individual experiences. This review has two objectives: 1) to describe the most likely neural circuit that mediates aggressive behavior towards pups in mice, including hormonal, neuroendocrine and neurochemical changes that may increase the probability of attacking pups; and 2) to discuss whether aggressive behavior toward pups in mice is rewarding, an impulsive or predatory response, or a form of maltreatment or adaptive behavior. We propose a neural model to explain aggressive behavior towards pups and discuss evidence suggesting that infanticidal and pup-directed aggressive behavior, although hard-wired in the brain, can be blocked or inhibited by changing the experiences of the subject prior to the access to pups.