"With the discovery of anesthesia, however, came a strange new problem: nobody was quite sure what was happening when the brain slipped from consciousness into this new, drugged state.
radiolab.org/story/anesthesia
The "mind" and "self" were formerly the domain of philosophers and priests. But in this hour of Radiolab, neurologists lead the charge on profound questions like "How does the brain make me?"
radiolab.org/story/91496-who-am-i
Basic info on brain activity in sleep, sleep disorders
ninds.nih.gov/disorders/brain_basics/understanding_sleep.htm