Knowing that spending time with dogs helps with anxiety and depression, researchers at the University of Basel in Switzerland decided to investigate what happens in the human brain when we interact with a fury friend. Volunteers petted either a dog or a stuffed animal with a hot-water bottle inside it while a machine measured the subjects' brain activity. Those who cuddled a real animal showed more activity in the prefrontal cortex, a brain region involved in social and emotional processes. This potentially therapeutic response continued even after the dog had left the room.