Stability of phase locked oscillations in the circadian clock

The existence of an internal timing mechanism in mammals has been well established and it is known that the circadian rhythm is generated in a bilateral structure contained in the hypothalamus called the Suprachaismatic Nucleus (SCN) consisting of 16000 neurons. Individually, each SCN neuron behaves like a clock, and the ensemble of neurons are capable of producing well synchronized and phase locked clock signals with precise timing patterns. In the presence of light, these clocks synchronize up to a phase shift with the light cycle. The clock mechanism is analyzed using bifurcation theory and the theory of nonlinear stabilization