The circadian clock of mammals is located in the suprachiasmatic nuclei (SCN) of the hypothalamus. While individual neurons of the SCN are capable of expressing circadian rhythms of electrical activity, a major unanswered question in the field of circadian rhythms biology is how the activity of the 16,000 to 20,000 neurons of the paired nuclei is coordinated to produce the characteristic behaviors of a circadian clock. This thesis presents a model mechanism by which the SCN neurons can be coordinated with one another and entrained by the environmental light-dark cycle. The model is based on...