Are there differences in the types of dreams that occur at different Essay

Are there differences in the types of dreams that occur at different times & Describe how sleep changes during the course of one night - Essay Example Polysomnography reveals a 50% drop in activity between alertness and phase 1 sleep. The eyes are shut during phase 1 sleep, but if woken up from it, then an individual might feel as if they have not slept yet. Stage 1 might last between 5 to 10 minutes (Harris 23). Stage 2 is a time of light sleep where polysomnographic readings portray irregular peaks and valleys, or negative and positive waves (Harris 24). These waves show spontaneous phases of muscle tone joined with phases of muscle relaxation. Muscle tone of this type can be witnessed in other phases of sleep as a response to audio stimuli (Jung 53). The heart deep slows, plus body temperature goes up. At this stage, the body gets ready to go into a deep sleep. These stages are deep sleep phases, with Stage 3 being less intense compared to Stage 4. These stages are referred to as delta or slow-wave sleep (Harris 24). In slow-wave sleep, particularly during Phase 4, the electromyogram records sluggish waves of high amplitude, showing a pattern of rhythmic continuity and deep sleep (Harris 24 and Jung 54). The time of non-REM sleep, abbreviated as NREM, comprises of phases 1 to 4 and lasts between 90 minutes to two hours, each phases lasting roughly five to 15 minutes (Harris 25). However, surprisingly enough, phase 2 and phase 3 reiterate backwards prior to attaining REM sleep. Thus, a normal sleep sequence has this pattern: waking, stage 1 to 4, and then back to 2 via 3, REM. In essence, REM sleep takes place just 90 minutes following sleep onset (Harris 25). REM sleep is discernible from NREM sleep through transformations in physiological states, including its distinguishing fast eye movements (Harris 25). Nevertheless, polysomnograms reveal wave patterns in REM similar as the ones in phase 1 sleep (Jung 57). During normal sleep (in individuals missing disorders of wake-sleep patterns or REM behaviour disorder), respiration and heart rate accelerate and become irregular, whereas the legs,