Fig. 3.

Circadian clocks in the SCN and other regions of the brain. In addition to the central pacemaker residing in the suprachiasmatic nucleus (SCN), other clocks exist in various regions of the brain. Light induces the generation of circadian rhythm in the master circadian clock, SCN. The SCN master clock seems to function as a synchronizer of the brain clocks. A metabolic signal, such as feeding, can be delivered to the CNS via a local clock in the DMH region. OB: olfactory bulb, SCN: suprachiasmatic nucleus, PVN: paraventricular nucleus, PVT: paraventricular nuclei of the thalamus, MBH: mediobasal hypothalamus, Arc: arcuate nucleus, CNS: central nervous system.