[Neural Mechanisms Underlying the Central Circadian Clock of the Suprachiasmatic Nucleus].

Circadian rhythms are oscillations with an approximately 24-h period and appear in most of the physiological events of our body. The suprachiasmatic nucleus (SCN) of the hypothalamus functions as the central circadian clock in mammals and entrains to the environmental light/dark (day/night) cycle. Here, I briefly review the molecular, cellular, and anatomical structures of the SCN, present findings of recent studies on the differential roles of multiple neuropeptides and neuropeptide-expressing neurons in the SCN, and discuss the mechanisms of the SCN network.