Evans Jennifer A, Leise Tanya L, Castanon-Cervantes Oscar, Davidson Alec J
Morehouse School of Medicine, Neuroscience Institute, 720 Westview Drive SW, Atlanta, GA 30310, USA
Department of Mathematics and Statistics, Amherst College, Amherst, MA 01002, USA.
Proc Biol Sci. 2015 Jul 7;282(1810). doi: 10.1098/rspb.2015.0769.
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控制，该系统是一组生物钟的集合，由下丘脑前部视交叉上核（SCN）内的中央起搏器调节。SCN功能的变化会对行为和生理产生显著影响；然而，很少有研究探讨昼夜节律行为的个体差异是否反映了SCN功能的变化。在这里，将PERIOD2::LUCIFERASE小鼠进行行为分析，以表征其在基线同步、重新同步速率和自由运行节律方面的个体差异。然后收集SCN切片进行离体生物发光成像，以深入了解SCN生物钟的特性如何影响行为节律的个体差异。首先，运动活动节律时间的个体差异与SCN节律的时间呈正相关。其次，模拟时差期间较慢的调整与SCN神经元之间更大程度的相位异质性有关。总的来说，这些发现突出了SCN网络在决定昼夜节律行为个体差异中的作用。此外，这些结果揭示了SCN的网络组织影响行为水平可塑性的新方式，并为旨在调节跨子午线旅行和轮班工作期间重新同步速率的潜在干预措施提供了见解。
