What stage of sleep is characterized by rapid eye movement?

The stage of sleep characterized by rapid eye movement (REM) is known for several distinct features that set it apart from other sleep stages. During REM sleep, the brain exhibits increased activity that resembles wakefulness, along with the characteristic rapid movements of the eyes beneath the eyelids. This stage is crucial for dreaming, memory consolidation, and emotional processing.

Additionally, during REM sleep, the body's muscle tone is significantly reduced, preventing individuals from acting out their dreams, a phenomenon known as REM atonia. This is in contrast to non-REM sleep stages, where such eye movements and brain activity patterns are not observed. The importance of REM sleep in overall health and well-being cannot be understated, as it plays a vital role in cognitive functions and emotional health.