BIFURCATION PROPERTIES OF THE 2 PROCESS MODEL

Daan's two process model is known to be one of the most powerful model s, covering various situations from free-running to sleep deprivation. In this study, bifurcation properties of the model dynamics as functi on of a gap, D, between the threshold processes are clarified using a circle map. As a function of D, we will show that the model has the di fferent types of the mutual entrainment regions that are intervened by the tangent bifurcation. The variable behavior of human circadian rhy thm is suggested to be systematically understood based on the bifurcat ion properties of the two process model.