Time In Rem Sleep example essay topic

Dreams are a form of cognitive activity that occur during sleep. Like vivid memories and daytime fantasies, dreams involve visual images in the absence of external visual stimulation. Some dreams are so realistic and well organized that we feel as though they must be real -- that we simply cannot be dreaming this time. Dreaming has always been the subject of controversy. Egyptian papyrus documents dating back to 2000 BC discuss dreams and their interpretations.

In ancient Greece the dreamer was believed to be in contact with the gods. In 1900, Sigmund Freud ushered in the modern age of dream research in his monumentally original book The Interpretation of dreams. According to Freud, dreams have a meaning which can be deciphered if one looks deeply enough. In his view, the dreams concerns the dreamers past and present, and it arises from unknown regions within.

He saw the dream as significantly analogous to a hysterical symptom. On the surface, they both appear meaningless and bizarre, but they become understandable when understood as veiled expressions of an unconscious clash between competing motives. Freud developed an elaborate theory and how the mind works while asleep. In 1953 sleep researchers led by Nathaniel Kleinman made the important discovery of rapid eye movement -- or REM -- sleep. Curious about the long-standing observation that the eyeballs of sleeping subjects in both humans and animals periodically move during sleep, they connected laboratory subjects to equipment that measured their brain waves, muscle tone, and eye movement. About 90% of the time when subjects were awakened during REM sleep, they reported a dream.

Prior to laboratory REM research, it was unknown how frequently Humans dreamed. Some theories even held that dreaming was a signal of mental disturbance. With laboratory REM research, however, subjects can be awakened after each REM period in order for researchers to extensively sample most mental activity that occurs during sleep. It was discovered that humans, and all mammals -- except the echidna or spiny anteater, and perhaps the duckbill platypus -- dream every night. In adult humans these dreams begin about 90 minutes after the sleep begins and recur about 90 minutes apart with increasing length, for a total of nearly 2 hours of REM dreaming per night. With approximately five dreams a night, humans will have about 136,000 dreams in a lifetime, spending the equivalent of six years in a REM dream state.

For a newborn, REM sleep constitutes 50% of sleep. This level gradually decreases to a stabilization level of 20 to 25% at adolescence. It reaches a low of 18% during old age. The severely mentally retarded and those with an extreme low I.Q. spend less time in REM sleep than normal subjects.

Variations in REM sleep also occur with some kinds of mental disorders. In the middle ages nightmares were thought to be the work of demons who were sent to pay sleepers for their sins, or they might try to suffocate you. If you were given to sexual fantasies or behaviour, they might have sexual intercourse with you. Night terrors are similar to nightmares but more severe. Night terrors usually occur during REM sleep. They occur early during the night while nightmares are usually events of the morning hours.

The dreamer may suddenly sit up with a surge in the heart and respiration rates, talk incoherently, and move about wildly. The dreamer is never fully awake, returns to sleep, and may recall a brief image of someone pressing on the chest. In contrast to the nightmare, memories of the episode are not vivid. Night terrors are often decreased by a minor tranquillize r at bedtime, which reduces the amount of time spent in stage 4 sleep.

Calvin Hall has linked dreams to life stresses, He has interviewed hundreds of dreamers and recorded the content of thousands of dreams, most dreams are simple extensions of the activities and problems of the day. If we are preoccupied with death or illness, sexual or aggressive urges, or moral dilemmas, we are likely to dream about them. The characters in our dreams are more likely to be friends and neighbours than spies, monsters, and princes. Dreams have been studied for hundreds of years and will continue to be studied for hundreds of years.

Some people may believe that these groups of subjective images and thoughts are our key to the past, present, and future.