Which term is used to describe REM sleep, emphasizing the paradox of brain activity with muscle atonia?

• A. REM sleep
• B. NREM sleep
• C. Jet lag
• D. Paradoxical sleep

Answer: (D)

Paradoxical sleep is the term that highlights the strange mix seen in REM sleep: the brain is highly active—as if awake—while the body is effectively paralyzed due to muscle atonia. This combination, with rapid eye movements and dreaming, creates a paradoxical picture, which is why this label is used. In contrast, non-REM sleep features slower, synchronized brain activity and lacks the vivid dreams and muscle paralysis prominent in REM, and jet lag describes circadian disruption rather than a sleep stage’s intrinsic characteristics.