Scientists know how to make mice angry--but mice know how to keep their cool

Male territoriality is a pretty well-defined scientific concept. Some animals mark their domain with rocks or urine, others attack intruders (and we've all seen guys who pick fights at the bar). Researchers at Stanford University Medical Center have taken a closer look at the roots of this rage in the mouse brain, and in a study published today in Neuron, they pinpoint the brain cells that give rise to male territorial aggression. They also found that in some cases, the mice know when fighting would be a faux pas. The neurons in question are clustered in the ventromedial hypothalamus (VMH), located deep in the center of the brain in a region that plays a role in many hormonally-controlled activities--things like fear, eating and sexual activity. It's old news that the VMH is involved in aggression, but the Stanford researchers narrowed the culprits down to approximately 4,000 cells with receptors that detect sex hormones.