Daily biological clocks in the mammal brain

Circadian rhythms in mammals are largely controlled by the suprachiasmatic nuclei (SCN) in the hypothalamus.

• Circadian rhythms are daily cycles in physiology and behavior found in multicellular organisms.
• The SCN functions as the central circadian clock, regulating various rhythms including activity/rest and neuroendocrine functions.
• Intrinsic circadian oscillators exist in the retina, indicating multiple sources of circadian regulation.
• Mammalian versions of certain genes from Drosophila, which play roles in circadian mechanisms, have been identified.
• In Drosophila, these genes interact in a feedback loop to create a circadian cycle in gene expression.
• Understanding the roles of mammalian clock genes in the SCN could enhance knowledge of the molecular basis of behavior.

Simplified