REM
Sleep is a transient and reversible state, which alternates with wakefulness when awake. It is an active process involving multiple and complex physiological and behavioral mechanisms in various systems and regions of the central nervous system. Two distinct states are identified in sleep: slower sleep, or non-REM sleep, and sleep with faster brain activity, or REM sleep.
Non-REM sleep is divided into three stages or stages according to the progression of its depth. On the other hand, the REM sleep is characterized by the cerebral activity of low amplitude and faster, by episodes of rapid ocular movements and maximum muscle relaxation. In addition, this stage is also characterized as the stage where dreams occur.
