Which brain structure is known as the master clock that regulates the sleep-wake cycle in humans?

• A. Cerebellum
• B. Suprachiasmatic nucleus
• C. Pineal gland
• D. Amygdala

Answer: (B)

Verified step by step guidance

1. Understand that the question is asking about the brain structure responsible for regulating the sleep-wake cycle, which is a circadian rhythm.
2. Recall that the circadian rhythm is controlled by an internal biological clock located in the brain.
3. Identify the brain structure known as the 'master clock' that synchronizes the body's daily cycles with environmental light and dark cues.
4. Recognize that the Suprachiasmatic nucleus (SCN), located in the hypothalamus, serves this role by receiving light information from the eyes and regulating melatonin production.
5. Conclude that among the options given, the Suprachiasmatic nucleus is the correct answer as it directly controls the sleep-wake cycle.