Data from: Neural correlates of individual differences in circadian behavior

Daily rhythms in mammals are controlled by the circadian system, which is a collection of biological clocks regulated by a central pacemaker within the suprachiasmatic nucleus (SCN) of the anterior hypothalamus. Changes in SCN function have pronounced consequences for behaviour and physiology; however, few studies have examined whether individual differences in circadian behaviour reflect changes in SCN function. Here, PERIOD2::LUCIFERASE mice were exposed to a behavioural assay to characterize individual differences in baseline entrainment, rate of re-entrainment and free-running rhythms. SCN slices were then collected for ex vivo bioluminescence imaging to gain insight into how the properties of the SCN clock influence individual differences in behavioural rhythms. First, individual differences in the timing of locomotor activity rhythms were positively correlated with the timing of SCN rhythms. Second, slower adjustment during simulated jetlag was associated with a larger degree of phase heterogeneity among SCN neurons. Collectively, these findings highlight the role of the SCN network in determining individual differences in circadian behaviour. Furthermore, these results reveal novel ways that the network organization of the SCN influences plasticity at the behavioural level, and lend insight into potential interventions designed to modulate the rate of resynchronization during transmeridian travel and shift work..

哺乳动物的日常节律由昼夜节律系统（circadian system）调控，该系统由一系列受下丘脑前部视交叉上核（suprachiasmatic nucleus, SCN）内中央起搏器调控的生物时钟组成。视交叉上核功能的改变会对行为与生理产生显著影响；然而，鲜有研究探讨昼夜行为的个体差异是否与视交叉上核功能变化相关。本研究将PERIOD2::LUCIFERASE小鼠暴露于行为学实验，以表征基线同步化、重同步速率与自由运行节律的个体差异。随后收集视交叉上核脑片开展离体生物发光成像，以探究视交叉上核时钟的特性如何影响行为节律的个体差异。研究结果显示：其一，运动活动节律的时间个体差异与视交叉上核节律的时间呈正相关；其二，模拟时差情境下的调整速度更慢，与视交叉上核神经元间更大的相位异质性存在关联。综上，本研究结果凸显了视交叉上核网络在决定昼夜行为个体差异中的作用。此外，该研究揭示了视交叉上核网络组织影响行为层面可塑性的全新路径，并为旨在调节跨时区旅行与轮班工作期间再同步速率的潜在干预手段提供了科学见解。