PSYCHOLOGY OF EMOTIONS

Detailed explanation-1: -Electroencephalography. These four sleep stages are called non-rapid eye movement (non-REM) sleep, and its most prominent feature is the slow-wave (stage IV) sleep. It is most difficult to awaken people from slow-wave sleep; hence it is considered to be the deepest stage of sleep.

Detailed explanation-2: -It is very difficult to wake someone during stages 3 and 4, which together are called deep sleep. There is no eye movement or muscle activity. People awakened during deep sleep do not adjust immediately and often feel groggy and disoriented for several minutes after they wake up.

Detailed explanation-3: -Stage 4: REM Sleep While your brain is aroused with mental activities during REM sleep, the fourth stage of sleep, your voluntary muscles become immobilized. Your brain also uses this time to cement information into memory, making it an important stage for learning.

Detailed explanation-4: -Sleep can be broadly segmented into rapid eye movement (REM) sleep and non-REM (NREM) sleep. Most adults will enter sleep from the drowsy state into NREM sleep. NREM sleep is divided into three sub-stages: stage N1, stage N2, and stage N3. Older classification had four stages of NREM sleep.