Non-REM Sleep

There are five stages in the sleep cycle, non-REM sleep covers 80% of one's sleep cycle, 20% is covered by REM. Rapid eye movement sleep is a state that normally occurs within 90 minutes of one falling asleep. This sleep state is characterized by random eye movement, low muscle tone, vivid dreaming, irregular heartbeat and breathing, as well as high brain activity. The brain activity during (REM) is comparable to the brain waves one would have while awake and functioning. Within an eight hour period the sleep stages cycle four to six times. The first stage of the sleep cycle begins as you close your eyes and begin to fall asleep. When in first non-REM stage of sleep breathing slows, the heartbeat becomes regular, while brain temperature and

This stage covers about 25% of overall sleep time, however REM sleep can account for 80% of an infant's total sleep time. Rapid eye movement sleep occurs more often in the second half of the sleep period, especially in the hours prior to waking up. Characteristics of REM sleep include random horizontal eye movements which can be tracked with the use of an electrooculography (EOG). It is believed that these eye movements are a result of internal visuals while dreaming. Low-amplitude mixed brain waves account for the majority of the brain's activity during this stage, these include: theta, alpha, and high frequency beta waves. The brain activity while in REM deep sleep is very similar to the brain activity of someone waking. Although the body is at rest in REM the brain's oxygen, and energy consumption match that of when one is conscious and active. Due to the similarity to waking state REM has been given the name “paradoxical sleep”. Muscles become paralyzed and unresponsive, this is phenomenon is known as “atonia”, it occurs because the region of the brain that controls muscle movement is almost completely suppressed, with exceptions for eye movement, and other systems such as the heart and diaphragm. The most vivid and memorable take place in the REM stage, although some dreams do occur in other stages. Muscular atonia (paralysis) is believed to be a built in defense mechanism that keeps humans from physically acting out the visuals which are experienced while dreaming. Michel Jouvet carried out a study in which a cat’s muscle inhibition nerve was severed, this resulted in the cat running, and playing even though it was in a deep stage of