The circadian clock network regulates daily rhythms in mammalian physiology and behavior to optimally adapt the organism to the 24-h day/night cycle. A central pacemaker, the hypothalamic suprachiasmatic nucleus (SCN), coordinates subordinate cellular oscillators in the brain, as well as in peripheral organs to align with each other and external time. Stability and coordination of this vast network of cellular oscillators is achieved through different levels of coupling. Although coupling at the molecular level and across the SCN is well established and believed to define its function as pacemaker structure, the notion of coupling in other tissues and across the whole system is less well understood. In this review, we describe the different levels of coupling in the mammalian circadian clock system - from molecules to the whole organism. We highlight recent advances in gaining knowledge of the complex organization and function of circadian network regulation and its significance for the generation of stable but plastic intrinsic 24-h rhythms.

中文翻译：

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哺乳动物昼夜节律时钟网络中的耦合概念。

昼夜节律时钟网络调节哺乳动物生理和行为的日常节律，以使生物体最佳地适应24小时昼夜循环。中央起搏器，下丘脑上视交叉上核（SCN），协调大脑以及周围器官中的下级细胞振荡器，以相互协调并与外部时间保持一致。通过不同程度的耦合，可以实现庞大的蜂窝振荡器网络的稳定性和协调性。尽管在分子水平和整个SCN上的偶联已被很好地建立，并被认为可以定义其起搏器结构的功能，但在其他组织和整个系统中偶联的概念却鲜为人知。在这篇综述中，我们描述了哺乳动物生物钟系统中从分子到整个生物体的不同耦合水平。