Refinement of a limit cycle oscillator model of the effects of light on the human circadian pacemaker
Refinement of a limit cycle oscillator model of the effects of light on the human circadian pacemaker
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DOI：
10.1006/jtbi.1998.0667
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发表时间：
1998-06-21
影响因子：
2
通讯作者：
Kronauer, RE
中科院分区：
文献类型：
--
作者：
Jewett, ME;Kronauer, RE
1990年，Kronauer提出了光对人体昼夜节律起搏器影响的数学模型。尽管该模型预测了人类昼夜节律起搏器对光照反应的许多一般特征，但现在可用的额外数据使我们能够改进原始模型。我们首先通过将光剂量响应曲线的结果纳入模型预测的光强度与起搏器驱动强度之间的关系来完善原始模型。然后使用来自三个亮光相位重置实验的数据来改进模型的幅度恢复特性。最后，使用来自广泛的相位重置实验的数据对该模型进行了测试并进一步完善，其中在昏暗的光背景下呈现 3 周期的亮光刺激。为了描述四次重置实验的结果，需要对原始模型进行以下重大改进：(i) 对于 150 至 10000 勒克斯之间的光照强度，光强度 (I) 与起搏器驱动之间的关系从 I-1/3 减少到 I-0.23；(ii) 将原始模型中的范德波尔振荡器替换为高阶极限环振荡器，以便幅度恢复在奇点附近较慢，在极限附近较快周期；（iii）模型中纳入了光对昼夜节律周期（tau（x））的直接影响，随着I的增加，tau（x）减少，这符合“阿绍夫规则”。这个改进的模型产生了以下可测试的预测：通过强光增强正常的昼夜节律幅度应该是困难的；在 0 型相位响应曲线 (PRC) 的临界点附近，斜率应比 1 型 PRC 中的斜率更陡；在强制不同步期间测量的昼夜节律周期应直接受到环境光强度的影响。 (C) 1998 年学术出版社。
In 1990, Kronauer proposed a mathematical model of the effects of light on the human circadian pacemaker. Although this model predicted many general features of the response of the human circadian pacemaker to light exposure, additional data now available enable us to refine the original model. We first refined the original model by incorporating the results of a dose response curve to light into the model's predicted relationship between light intensity and the strength of the drive onto the pacemaker. Data from three bright light phase resetting experiments were then used to refine the amplitude recovery characteristics of the model. Finally, the model was tested and further refined using data from an extensive phase resetting experiment in which a 3-cycle bright light stimulus was presented against a background of dim light. In order to describe the results of the four resetting experiments, the following major refinements to the original model were necessary:(i) the relationship between light intensity (I) and drive onto the pacemaker was reduced from I-1/3 to I-0.23 for light levels between 150 and 10000 lux;(ii) the van der Pol oscillator from the original model was replaced with a higher-order limit cycle oscillator so that amplitude recovery is slower near the singularity and faster near the limit cycle;(iii) a direct effect of light on circadian period (tau(x)) was incorporated into the model such that as I increases, tau(x) decreases, which is in accordance with "Aschoff's rule".This refined model generates the following testable predictions: it should be difficult to enhance normal circadian amplitude via bright light; near the critical point of a type 0 phase response curve (PRC) the slope should be steeper than it is in a type 1 PRC; and circadian period measured during forced desynchrony should be directly affected by ambient light intensity. (C) 1998 Academic Press.