Bad dreams and nightmares are among the most startling and emotionally potent of remembered dreams. Even a partially remembered disturbing dream can linger in our waking minds. But what do we know about this phenomenon of disturbed dreaming? And what's the difference between a bad dream and a nightmare?
There is now good evidence that parts of the brain may be awake while other parts are asleep. Sleepwalking is a premiere example: The portion of the brain capable of generating complex behaviors is awake while those portions which normally monitor our activity and lay down memory of our behaviors are asleep.