In mammals, the suprachiasmatic nucleus (SCN), located in the hypothalamus serves as the master biological clock and precisely regulates circadian rhythms through a complex network structure. As a central pacemaker, the SCN has two primary functions: one is to synchronize the daily rhythms in physiological and behavioral activities; the other is to entrain the endogenous rhythms to the external light–dark cycle. A deep understanding of the SCN network structure is crucial for elucidating the functional mechanisms of the biological clock system. In this review, we systematically summarized the impact of the SCN network structure on functional regulation under light stimulation based on mathematical models. Studies have shown that the coupling between the light-sensitive subgroups in the left and right nuclei of the SCN can enhance the entrainment ability. As an integrated network structure, the SCN may have the characteristics of the small-world network or the scale-free network, as these properties are more conducive to the realization of functions. Additionally, the higher-order coupling mechanism within the SCN can effectively expand the entrainment range. These theoretical research results offer new insights into the relationship between the SCN network and functions and provide crucial theoretical guidance and validation directions for subsequent experimental research.
Feng et al. (2025) studied this question.