REM sleep
Has anyone figured out the purpose of rapid eye movement during sleep? Certainly, it's an indicator of dreaming, but why the darting eyes? Are we actually looking at the back of our eyelids? Probably not. More likely, our visual cortex is being stimulated by what we 'see' in our dreams and flickering eye movements are a by-product of the action of shifting our visual fields in our mind's eye (whew..) Sort of like some of the movements we might make in deep sleep. So why are they so fast? I mean, it is called rapid eye movement. Are we seeing things at an accelerated pace? Do we then process, make decisions and likewise think faster in deep sleep? Is this a primordial way of thinking, where a split second meant the difference between life and death?