During which sleep stage is the arousal threshold highest?

During which sleep stage is the arousal threshold highest?

• A. N2
• B. N1
• C. REM
• D. N3

Answer: (D)

Arousal threshold tracks how deeply you’re sleeping—the deeper the sleep, the harder it is to wake. The highest threshold occurs in the deepest stage of non-REM sleep, known as slow-wave sleep. In this stage, the brain shows large, synchronized delta activity and sensory processing is greatly dampened, making external stimuli less likely to bring someone to wakefulness. In lighter sleep stages, such as the transition from wake to sleep and the lighter non-REM stage, stimuli are more easily noticed and can wake you more readily. REM sleep also has wakefulness-like brain activity, but it isn’t as resistant to arousal as the deepest non-REM sleep. So, the arousal threshold is greatest during slow-wave sleep.

Arousal threshold tracks how deeply you’re sleeping—the deeper the sleep, the harder it is to wake. The highest threshold occurs in the deepest stage of non-REM sleep, known as slow-wave sleep. In this stage, the brain shows large, synchronized delta activity and sensory processing is greatly dampened, making external stimuli less likely to bring someone to wakefulness. In lighter sleep stages, such as the transition from wake to sleep and the lighter non-REM stage, stimuli are more easily noticed and can wake you more readily. REM sleep also has wakefulness-like brain activity, but it isn’t as resistant to arousal as the deepest non-REM sleep. So, the arousal threshold is greatest during slow-wave sleep.