Consciousness is a state of awareness. This includes a person’s feelings, sensations, ideas, and perceptions. There are many different states of consciousness.
Sleep is a state of altered consciousness, characterized by certain patterns of the brains activity and inactivity. An altered state of consciousness is when a person is not completely aware of their surroundings. Some researchers believe that we sleep to clear our minds of useless information. Other people believe that it is a type of primitive hibernation: we sleep to conserve energy.
There are four stages of sleep. In the first stage (10 min. into sleep), your pulse slows down and your muscles begin to relax. Your breathing becomes uneven, and your brain waves grow irregular. During the second stage, your brain waves occasionally shift from low aptitude, high frequency waves to high aptitude, low frequency waves. Your eyes then start to roll slowly back and forth. Thirty minutes into your sleep you enter stage three. In this stage, large-amplitude delta waves begin to sweep your brain about every second. Stage four is the deepest sleep a person gets into. Large regular delta waves occur about 50% of the time. This indicates a person is in a deep sleep. Talking out loud, sleepwalking, and bed wetting all occur during this deep sleep stage. Things that happen during this stage leave no trace on a person’s memory. While in stage four, a person goes through a stage of sleep called REM. REM sleep is a stage of sleep characterized by rapid eye movement, a high level of brain activity, a deep relaxation of the muscles, and dreaming.
Another state of consciousness is hypnosis. Hypnosis is a state of consciousness resulting from a narrowed focus of attention and characterized by heightened suggestibility. By allowing the hypnotist to direct them, people can be made conscious of things they’re usually not aware of. While a participant is hypnotized, they become
References: - Psychology Glencoe (Book) - www.alteredstatesofconsciousness.org/ - www.skepdic.com/altstates.html - www.unexplainedstuff.com/.../Altered-States-of-Consciousness.html