system
Given the following post, respond as if you're commenting on Reddit:
human
What's the difference between being knocked out and being unconcscious when you sleep?
gpt
Sleep is a complicated, organized process in which your brain slows down but does not stop working. Many parts of your brain remain active while you sleep. 

For example, you might sleep through a quiet conversation in the same room, but then suddenly wake up when someone says your name. The part of your brain that processes sounds is active enough to recognize your name, interpret that it might be important, and send a signal that prompts you to wake up. 

Unconsciousness is different because it's an abnormal state. The system controls wakefulness is either not working properly, or is not able to communicate with the rest of the brain. An unconscious person cannot be awakened by any stimulus. 

In the hospital, this is one of the quick ways we distinguish true unconsciousness from sleep (or acting). We provide a noxious stimulus, something that a sleeping or wakeful person would be unable to ignore, such as ammonia vapors in the nose or a painful rub on the sternum. A sleeping person would respond by waking up, but an unconscious person cannot wake.