In the video BBC Horizon- The Secret You, professionals explained how there have been cases where they have detected brain responses to stimuli in a physically unresponsive person. In a case of a woman in a vegetative state, when she was told to imagine playing tennis, the parts of the brain that are responsive when a conscious person plays tennis, responded. This shows that the woman's brain was somehow able to respond to an outside stimulus, even though her body was not.
This reminded me of Locked-in Syndrome. Locked-in Syndrome is when a patient is seemingly in a coma but they are actually able to sense their surroundings. Someone with Locked-in Syndrome can not respond physically to the outside stimuli. This article is an example of a patient with Locked-in Syndrome: http://www.bmj.com/content/331/7508/94.full
It is interesting to me how people can seem completely unaware but their brain is actually sensing and responding, but the signals are not reaching their body.