Mice and rats have long been used in medical research because of their biological similarities to humans. The tiny animals have already shown an ability to recognize objects, push buttons and find their way through complex paths. Now, scientists have trained rats to drive small vehicles created for them. One of the main findings of the experiment was that the driving activity seemed to help the rats relax. Researchers at the University of Richmond in Virginia led the experiment. Their findings were published in Behavioural Brain Research. The team built tiny cars out of plastic and other materials. The vehicles had an opening at one end where electrical wires were attached. By touching one of three different wires, the rat could steer the car in different directions.