What is the difference between being asleep and being unconscious?

Sleeping is a state actively chosen by the manas, and during sleep one is generally quite peaceful, able to rest contentedly in the sleeping state. If the manas feels it has slept enough, or there is some matter at hand, it will decide to wake up. Falling into a dead faint, however, is a passive and unwilling state. Because the body has been severely injured, the six sense-objects cannot be properly transmitted to the supreme faculty (rūpa-prasāda), so the six consciousnesses are unable to continue their activity, and the activity of the five aggregates (pañcaskandha) has no choice but to cease. When the manas becomes aware of this condition of the five-aggregate body, it is extremely anxious and unwilling; therefore it always seeks an opportunity to wake up. As soon as the body recovers a little, it will struggle to get up and move about; then, when the body truly cannot manage it, it faints once again. Some people may even send their soul out of the body to inform their family members and seek help from others. This shows that the manas is not willing to lie unconscious, unable to use the five-aggregate body. He relies on the five-aggregate body in order to survive within worldly dharmas, and so He clings to the five aggregates and the six consciousnesses, unwilling to die and unwilling to remain unconscious.