"Are you ready to go into the spaceship? Remember to stay very still!" This is what you hear before the bed you are lying down on starts to slide into a long, tube shaped machine. You can almost imagine that it really is a spaceship, and that you, with your helmet, earphones and small viewing screen, are the pilot, about to blast off into outer space! Your favorite space movie starts playing on the screen, and the machine suddenly turns on, making very loud sounds like "boop-boop-bleep", and you imagine you are in an alien spaceship battle. But this is no spaceship - it is a special machine called a magnetic resonance imaging (MRI) scanner, and it can take hundreds of pictures of your brain that help us to see how your brain works and what it is made of.