Can scientists tell if someone is conscious?

In a landmark study in 2006, Adrian Owen and his colleagues used an fMRI scanner to investigate if a person in a ‘vegetative state’ was conscious or not. Because different parts of your brain are responsible for doing different things, Owen could see which parts of the patient’s brain became active at any one time. When asked to imagine playing tennis or moving around her house, the patient’s brain lit up in exactly the same way as healthy volunteers’ brains, showing that she was indeed conscious, but unable to respond.