Consciousness Essays - Sleep, Non-rapid Eye Movement Sleep

Consciousness Numerous factors determine when and why you feel tired, full of energy, and hungry. A person's state of consciousness and awareness varies throughout the day and depends on a person's activity, environment, and time clock. As a human we have what is called circadian rhythms, which simply explains our daily highs and lows. An example of your basic up and down rhythm would be the sleep/wake cycle. Sunlight regulates the sleep/wake cycle by causing the suprachiasmatic nucleus to decrease its production of melatonin in the early morning and increase it in the evening. Melatonin is a hormone that if increased in blood levels makes an individual drowsy or tired and if decreased will make them more alert. Certain individuals will experience that their biological clock is often out of sync. This can be explained sometimes from either jet lag, working the night shifts or graveyards, and Monday-morning fog. Sleep in itself has its own biological patterns and rhythms. Hans Berger introduced the electroencephalograph to us so that we would be able to measure the patterns and rhythms of sleep through a record called an EEG. Two different patterns of sleep are REM sleep and NREM sleep. The NREM sleep actually has four stages involved in it. During the first stage a person becomes slightly drowsy because of the mixture of alpha and theta brain waves. At the second stage, an individual tends to have bursts of brain activity for a short time, which in terms are called sleep spindles. The second stage also involves theta brain waves and the beginning of delta waves. The third and fourth stages of NREM sleep are often referred to as "slow-wave sleep". Both of these stages are measured by the amount of delta brain wave activity. During REM sleep, the sleeper is unconsciously active. His eyelids may flutter, he may have increased heart rate, and occasional muscle spasms. The two basic sleep theories are the evolutionary and restorative theories of sleep. The evolutionary theory of sleep suggests that our sleep patterns are based on or defined by evolution. The second theory simply offers that sleeping restores and rejuvenates the body through physiological processes. Sleeping disorders have a variety of effects on a person. Insomnia simply disallows an individual to actually fall into deep sleep and feel rested in the morning. Sleepwalking and night terrors are much more common in childhood then in the adult life and occur during the deepest stages of NREM sleep. When a person repeatedly stops breathing during his sleep it is called sleep apnea. This sleeping disorder usually tends to occur in older more heavy weight men. Another sleeping disorder is narcolepsy, which sends an individual in an instant phase of deep REM sleep regardless of where they are and whom they are with. Dreaming is yet another state of consciousness. A dream is simply an unfolding episode of mental images that involve characters and events. Dreams usually tend to occur during REM sleep but can occur during NREM sleep as well. We dream on a variety of topics, subjects, and individuals. No dream can be exactly interpreted or defined, therefore people have always been fascinated with what, why, and how we dream. An unpleasant and almost terrifying type of dream is a nightmare. This is a very vivid, almost real like state that produces quick anxiety and a sense of helplessness in the situation. Another type of dream would be the lucid dream in which the dreamer knows he is dreaming and can often guide the course of his dream. Hypnosis is a very controversial state of awareness because of its changes to an individual's perception, memory, and behavior. Not everyone can be hypnotized. The most susceptible people are those who approach it with a positive attitude. When subjects are deeply hypnotized they have said to experience detachment from their bodies or extreme relaxation which changes their subjective experience of consciousness. When a posthypnotic suggestion is made during hypnosis the subject will act on that for a short time after being hypnotized and sometimes up to a couple of days after the session. Ernest Hilgard suggested that while hypnotized a person experiences dissociation that splits consciousness into two or more streams of mental activity. Psychoactive drugs are chemical substances that alter moods, perceptions, as well as a person's conscious state. After abusing a psychoactive drug for a period of time your body will become physically adapted to it and create a tolerance for it and in return a person will increase their intake of that drug to feel the