The circadian system of mammals is composed of a hierarchy of oscillators that function at
the cellular, tissue, and systems levels. A common molecular mechanism underlies the cell-
autonomous circadian oscillator throughout the body, yet this clock system is adapted to
different functional contexts. In the central suprachiasmatic nucleus (SCN) of the
hypothalamus, a coupled population of neuronal circadian oscillators acts as a master
pacemaker for the organism to drive rhythms in activity and rest, feeding, body temperature …