Paradoxical Sleep
Paradoxical sleep is another term for activated sleep, deep sleep, desynchronized sleep, rapid eye-moyement or REM sleep, para sleep, and rhombencephalic sleep. Since dreaming occurs almost exclusively during this sleep state, it is also called dreaming sleep or D-state. During paradoxical sleep your brain is very active, and your eyes move in a sharp, back and forth motion as opposed to a slower, more rolling fashion that occurs in other stages of sleep. However, even though your eyes are moving a lot and your brain is active, your muscles are in a state of almost complete paralysis. That's why it's paradoxical sleep--you're asleep, your brain is active and your muscles are inactive.