The brain’s daily internal clock system in mammals

Circadian rhythms in humans and other mammals are regulated by an endogenous clock in the suprachiasmatic nuclei of the hypothalamus.

• Circadian rhythms involve cyclical changes in physiology and behavior.
• These rhythms are synchronized with the light-dark cycle in the environment.
• Circadian rhythms can persist even in constant environmental conditions.
• The suprachiasmatic nuclei contain cells with unique properties that drive these rhythms.
• The central clock influences daily activities and physiological processes.

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