Which stage of sleep comes before rem sleep?

NREM (non rapid eye movement ) is the stage of sleep comes before REM sleep.

Explanation:

Sleep stages are nothing but electrical wave activities in the brain. This wave movement is measured by an electroencephalogram (EEG). There are 2 main stages in our sleep such as REM and NREM.

The NREM is the first stage of the sleep cycle. It has 3 substages - N1, N2, N3 stages. In the N1 stage individuals feel sleepy, hallucinates. It is the light sleep stage and people can awake from this stage of sleep easily.

N2 stage is the next sleeping stage. In this stage, the electrical waves are more and called theta waves. Here, it is hard to awake. Sleep spindles, K - complex are found in this stage, which helps in a deep sleep.

N3 is slow-wave sleep. The waves are called delta waves. This is the deep sleep stage. It is difficult for a person to awake from this sleep. The walking during sleep occurs in this stage.

REM or rapid eye movement is a deep sleep stage. It is also called paradoxical sleep. Here, the brain is more active and the body is paralyzed. During this stage a person dreams.

where is the scientific experiment?