Night Terrors, for example, involve the partial arousal out of non-REM sleep.

This reactivation of the memory traces has also been seen in non-REM sleep specifically for hippocampus-dependant memories.

"At various times throughout the day, it will go into REM and non-REM sleep."

Delta activity is an indicator of depth of sleep within non-REM sleep.

Then we move into deeper, dreamless sleep, called non-REM sleep, that lasts several hours.

The purpose of non-REM sleep is even more mysterious.

The collective output of many such groups leads to what scientists called non-REM sleep, when dreams do not occur.

Stages 1-3 are together called non-REM sleep.

Rapid eye movement sleep is deeper than non-REM sleep.

During non-REM sleep, the tonic drive to most respiratory muscles of the upper airway is inhibited.