Your psychology instructor states that during a night of sleep, a person goes through cycles of light and deep sleep, while also experiencing bodily changes

Question

Using a description of the stages of NREM and REM, describe a night of sleep, including the type of brain waves present and the characteristics of each NREM stage and the characteristics of REM sleep.

What will be an ideal response?

Answer 1

Answer will include that the two most basic states of sleep are non-REM (NREM) sleep, which occurs during Stages 1, 2, 3, and 4, and REM sleep, with its associated dreaming. NREM sleep is dream free about 90 percent of the time and is deepest early in the night during the first few Stage 4 periods. Your first period of Stage 1 sleep also usually lacks REMs and dreams. Later Stage 1 periods typically include a shift into REM sleep. As you begin the process of going to sleep, your eyes close, breathing becomes slow and regular, the pulse rate slows, and body temperature drops. Soon after, the four separate NREM sleep stages occur. NREM Stage 1: As you enter light sleep, your heart rate slows even more. Breathing becomes more irregular. The muscles of your body relax. This may trigger a reflex muscle twitch called a hypnic jerk. In Stage 1 sleep the EEG is made up mainly of small, irregular waves with some alpha. Persons awakened at this time may or may not say they were asleep. NREM Stage 2: As sleep deepens, body temperature drops further.
Also, the EEG begins to include sleep spindles, which are short bursts of distinctive brain-wave activity. Spindles seem to mark the true boundary of sleep. Within four minutes after spindles appear, most people will say they were asleep. NREM Stage 3: In Stage 3, a new brain wave called delta begins to appear. Delta waves are very large and slow. They signal a move to deeper sleep and a further loss of consciousness. NREM Stage 4: Most people reach deep sleep in about an hour. Stage 4 brain waves are almost pure delta and the sleeper is in a state of oblivion. If awakened in this stage, the sleeper will wake up in a state of confusion and may not remember what awakened them. Fluctuations in sleep hormones cause recurring cycles of deeper and lighter sleep throughout the night. During these repeated periods of lighter sleep, the sleeper's eyes occasionally move under the eyelids. Rapid eye movements (REMs) are associated with dreaming. In addition, REM sleep is marked by a return of fast, irregular EEG patterns similar to Stage 1 sleep. In fact, the brain is so active during REM sleep that it looks as if the person is awake. REM sleep (dream sleep) is a time of high emotion. The heart beats irregularly. Blood pressure and breathing waver. Both males and females appear to be sexually aroused with males usually having an erection and genital blood flow increasing in women. During REM sleep the body becomes quite still, as if you were paralyzed, which keeps one from acting out their dreams.