Reply To: T-shirt designers unite and take over

[Zara]

NREM sleep is divided into four stages:

Stage 1 – occurs in the beginning of sleep, with slow eye movements. Disappearance of alpha waves and appearance of the theta wave. People in this stage often believe that they are fully awake. During the transition into Stage 1 sleep, it is common to experience hypnic jerks.
Stage 2 – the person is unconscious[verification needed], though awakened easily. No eye movements occur, and dreaming is very rare during this stage. EEG recordings tend to show characteristic “sleep spindles” and “K-complexes” during this stage.
Stage 3 – transition between stage 2 and stage 4. Delta waves begin to occur which are associated with “deep” sleep.
Stage 4 – slow-wave sleep (SWS) refers to the “deepest” stage of sleep in which there is a continuation of the delta wave. Dreaming is more common in this stage than in other stages of NREM sleep though not as common as in REM sleep. The content of SWS dreams tends to be disconnected and not as vivid as those that occur during REM sleep. This is also the most common stage in which parasomnias occur.