How does the brain work when your sleeping?

When you are asleep, your brain IS actually working. It is never not working. You always breathe, whether your forcing it or not. That is called involuntary breathing. I do not know how you dream, but I know it maybe has to do with your cerebrum..? That is where your memories and thoughts are saved. -1/9/10

If your brain is not working, how do you dream and breathe . Your brain is always working until you are brain-dead .