The deep secret of the brain is that not only the spinal cord but the entire central nervous system works this way: internally generated activity is modulated by sensory input. In this view, the difference between being awake and being asleep is merely that the data coming in from the eyes anchors the perception.
David EaglemanAs Carl Jung put it, "In each of us there is another whom we do not know." As Pink Floyd sang, "There's someone in my head, but it's not me."
David Eagleman