Gu Changgui, Li Jiahui, Zhou Jian, Yang Huijie, Rohling Jos
Business School, University of Shanghai for Science and Technology, Shanghai, China.
Laboratory for Neurophysiology, Department of Cell and Chemical Biology, Leiden University Medical Center, Leiden, Netherlands.
Front Physiol. 2021 Aug 16;12:678391. doi: 10.3389/fphys.2021.678391. eCollection 2021.
A master clock located in the suprachiasmatic nucleus (SCN) regulates the circadian rhythm of physiological and behavioral activities in mammals. The SCN has two main functions in the regulation: an endogenous clock produces the endogenous rhythmic signal in body rhythms, and a calibrator synchronizes the body rhythms to the external light-dark cycle. These two functions have been determined to depend on either the dynamic behaviors of individual neurons or the whole SCN neuronal network. In this review, we first introduce possible network structures for the SCN, as revealed by time series analysis from real experimental data. It was found that the SCN network is heterogeneous and sparse, that is, the average shortest path length is very short, some nodes are hubs with large node degrees but most nodes have small node degrees, and the average node degree of the network is small. Secondly, the effects of the SCN network structure on the SCN function are reviewed based on mathematical models of the SCN network. It was found that robust rhythms with large amplitudes, a high synchronization between SCN neurons and a large entrainment ability exists mainly in small-world and scale-free type networks, but not other types. We conclude that the SCN most probably is an efficient small-world type or scale-free type network, which drives SCN function.
位于视交叉上核（SCN）的主时钟调节哺乳动物生理和行为活动的昼夜节律。SCN在调节过程中有两个主要功能：一个内源性时钟在身体节律中产生内源性节律信号，一个校准器将身体节律与外部明暗周期同步。已确定这两个功能依赖于单个神经元的动态行为或整个SCN神经元网络。在本综述中，我们首先介绍从实际实验数据的时间序列分析中揭示的SCN可能的网络结构。发现SCN网络是异质且稀疏的，即平均最短路径长度非常短，一些节点是具有大节点度的枢纽，但大多数节点具有小节点度，并且网络的平均节点度较小。其次，基于SCN网络的数学模型综述SCN网络结构对SCN功能的影响。发现主要在小世界和无标度类型网络中存在具有大振幅的稳健节律、SCN神经元之间的高度同步以及大的夹带能力，而在其他类型网络中则不存在。我们得出结论，SCN很可能是一种有效的小世界类型或无标度类型网络，它驱动SCN功能。
