Week Six Sleeping and Dreaming
PSY/240
Sleeping and Dreaming Sleep is considered a natural state in which there is reduced consciousness, reduced sensory activity, and inactivity of all muscles. Sleep is needed for the body to recharge, grow, and is essential for health and well-being. There are three standard psychophysiological measures of sleep and they define the stages of sleep. They are the electroencephalogram (EEG), the electrooculogram (EOG), and the neck electromyogram (EMG). There are four different stages of EEG sleep. Stage 1 EEG is a low-voltage, high-frequency signal slower than being awake. When going from stage to stage the EEG voltage increases and the EEG frequency decreases. Once a person goes from stage 1 to stage 4, the cycles of sleep go back and forth throughout the stages while a person is sleeping. Each cycle is about 90 minutes long. REM sleep is associated with stage 1 EEG while NREM sleep is a combination of all other stages. Stages 3 and 4 are considered slow-wave sleep or SWS due to the delta waves. During REM sleep people have rapid eye movements. Dreaming occurs during the REM stage of sleep. Some people believe that external stimuli can affect their dreams. Some people believe dreams are quick and only last a few minutes, while research suggests they last as long as the person is dreaming. Some people say they do not have any dreams, but more than likely they just do not remember their dreams. Penile erections are said to be associated with sexual dreams, but there is no direct research to prove this. Another common belief is that sleep talking and sleep walking only occurs while a person is dreaming. Sleep walking occurs during stage 2 and 3, not during the REM or dream stage. The two theories for sleep are the recuperation theory and the circadian theory. The recuperation theory is that