Thesexand the violence isinterconnected in the brainof mice. The activity ofun small group of neurons locatedon theventromedial hypothalamus region(VHM) of the male brain determines whether to start a fight or have sexual relations, and there is good reason to think that human beings have a similar circuit, a study published in the scientific journal suggestsNature.
Specifically, David Anderson, from the California Institute of Technology (Caltech), and his colleagues have identified that a part of the neurons in this nucleus is activated only in case of aggression and others are activated only in case of mating, but there is close 25% that is activated in both situations.
By implanting fiber optics in the brains of the rodents, the researchers were able to artificially modify the activity of these neural networks at will. In this way they were able to verify thatwhile the circuit of aggressiveness lay idle, the ratsignored the presence of male intrudersthose they would naturally attack, virtually eliminating violent behavior. Conversely,when neurons fired out of time, mice became so aggressive that they even attacked inanimate objectslike an inflated glove, to castrated males or to females they previously tried to woo. However, if these same neurons were activatedwhile the animal was already immersed in sexual activity, no violent behaviors appeareds. The neurons analyzed, the scientists conclude, are activated in aggressive behaviors and are inhibited during mating.
According to Anderson, it could be deduced from this study that a dysfunctional connection in these areas of the brain could explain why some individuals have inappropriate sexual and violent urges.
