Scientists are studying what makes flies and mice lash out
Eye of Science/Science Source
Male mice in David Anderson’s Caltech laboratory are typical rodents. Mellow most of the time, they’ll defend their cages if provoked — chasing male intruders away. The mice will lunge and nip until one admits, paws up, social defeat. Rarely do they actually hurt each other.
But with the flick of a switch, Anderson’s team can convert an ordinary lab mouse into a vicious brute that won’t back down. Like Bruce Banner morphing into the Hulk, the mouse seems to have no choice but to let the monster spring forth, inflicting bite after bite on its cowering victim.
To draw out the animal’s natural aggression, scientists activate a small group of nerve cells, or neurons, identified by Anderson’s group and others, that act as a control center for aggressive behavior. Turning on those brain cells instantly increases a mouse’s appetite to