At what point do "you" end and the outside world begins? It might feel like a weird question with an obvious answer , but your brain has to work surprisingly hard to judge that boundary. Now, scientists have linked a specific set of brain waves in a certain part of the brain to a sense of body ownership. In a series of new experiments, researchers from Sweden and France put 106 participants through what's called the rubber hand illusion , monitoring and stimulating their brain activity to see