Mice lacking a set of receptors in one type of neuron in the brain developed compulsive, anti-social behaviors, scientists have found. The importance of the receptor, called mGluR5, in other areas of the brain had been previously established. Until now, however, no one had studied their specific role in a cell type known as parvalbumin-positive interneurons, thought to be important in general cognition and generating certain types of oscillatory wave patterns in the brain.