This original paper analyses a very interesting example of evolutionary adaptation. In rat infected with the brain parasite Toxoplasma gondii avoidance responses to cat odors are abolished and rats tend to approach places marked with odors of their predator. Interestingly Toxoplasma requires the cat to sexually reproduce. In the present article, the authors investigated the brain activity of infected rats. They found that “Toxoplasma infection alters neural activity in limbic brain areas necessary for innate defensive behavior in response to cat odor”. Furthermore “Toxoplasma increases activity in nearby limbic regions of sexual attraction when the rat is exposed to cat urine”. These amazing data clarify how a parasite can, for reproductive needs and in an evolutionary adaptive manner, manipulate the behaviour of its host through an action on its brain. This switch of rat behaviour from innate fear of cat odor to attraction is quite remarkable and should interest a broad readership