Photic desynchronization of two subgroups of circadian oscillators in a network model of the suprachiasmatic nucleus with dispersed coupling strengths.
Photic desynchronization of two subgroups of circadian oscillators in a network model of the suprachiasmatic nucleus with dispersed coupling strengths.
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DOI：
10.1371/journal.pone.0036900
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发表时间：
2012
期刊：
影响因子：
3.7
通讯作者：
Indic P
中科院分区：
文献类型：
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作者：
Gu C;Liu Z;Schwartz WJ;Indic P
视交叉上核(SCN)是哺乳动物的主生物钟，由数千个神经元振荡器组成，表达不同的内在周期。这些振荡器形成了一个耦合网络，在恒定的黑暗中有一个大约24小时的自由运行周期，并且可以携带到外部的明暗周期(T周期)。耦合对网络周期及其夹带范围的确定起着重要的作用。在大鼠的实验表明，SCN内的两个振荡器亚群，即接受光输入的腹外侧(VL)亚群和耦合到VL的背内侧(DM)亚群，可以在短(22小时)T周期内被去同步化，VL被带到周期中，而DM自由运行。我们使用一个改进的Goodwin模型来理解亚群到短(22-h)和长(26-h)T周期的夹带如何受到光强度、接受光输入的神经元的比例以及耦合异质性的影响。我们发现，模型中光敏感神经元比例的临界值与实际的实验估计值是一致的，而模型中包含的分散耦合可以解释VL和DM在22小时比26小时的T周期下更容易去同步的实验观察。SCN内的异质性细胞间耦合可能是复杂行为模式产生的核心。
The suprachiasmatic nucleus (SCN) is the master circadian clock in mammals and is composed of thousands of neuronal oscillators expressing different intrinsic periods. These oscillators form a coupled network with a free-running period around 24 h in constant darkness and entrainable to the external light-dark cycle (T cycle). Coupling plays an important role in setting the period of the network and its range of entrainment. Experiments in rats have shown that two subgroups of oscillators within the SCN, a ventrolateral (VL) subgroup that receives photic input and a dorsomedial (DM) subgroup that is coupled to VL, can be desynchronized under a short (22-h) T cycle, with VL entrained to the cycle and DM free-running. We use a modified Goodwin model to understand how entrainment of the subgroups to short (22-h) and long (26-h) T cycles is influenced by light intensity, the proportion of neurons that receives photic input, and coupling heterogeneity. We find that the model’s critical value for the proportion of photically-sensitive neurons is in accord with actual experimental estimates, while the model’s inclusion of dispersed coupling can account for the experimental observation that VL and DM desynchronize more readily under the 22-h than under the 26-h T cycle. Heterogeneous intercellular coupling within the SCN is likely central to the generation of complex behavioral patterns.
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影响因子：
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