REM Sleep mystery has been solved

For taking up so much of our time, there is quite a bit we still don't know about sleep. Why do we need it? What happens during sleep? What happens if we don't get enough?

The threshold between what we do know and what we don't know however has shrunk.

In our deepest level of sleep, our brain takes part in an activity known as REM sleep, or Rapid Eye Movement. During this phase of sleep our eyes can be seen shifting left to right underneath our eye lids. The question is: why?

A team of neuroscientists have now figured out why.

The eye flickers during REM sleep carry many similarities to when people see a new image when they're awake. This is indicative of a "change of scene" during a dream.

This would explain why REM sleep is perceived in fetuses and blind people as well; the mental imagery is changing.