Entrainment versus chaos in a model for a circadian oscillator driven by light-dark cycles
Entrainment versus chaos in a model for a circadian oscillator driven by light-dark cycles
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DOI：
10.1023/a:1026410121183
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发表时间：
2000-10-01
影响因子：
1.6
通讯作者：
Goldbeter, A
中科院分区：
文献类型：
--
作者：
Gonze, D;Goldbeter, A
几乎所有生物体都有昼夜节律，周期接近24小时。这些节律构成了一类重要的生物振荡器，它们呈现出自然地受到光暗（LD）周期强迫的特征。为了研究这种强迫可能导致混沌的条件，我们考虑了一个昼夜极限环振荡器模型，并评估了当光敏参数被LD周期性强迫时的动力学行为。我们确定作为一个函数的强制周期和光引起的变化的光敏参数的各种模式的动态行为，如准周期性，夹带，倍周期和混乱的发生的振幅。振荡行为的类型显着依赖于强迫波形，因此夹带的域增长的区域的混乱作为强迫函数逐渐从方波到正弦波的牺牲。还研究了周期性或非周期性振荡的相位对控制参数的光致变化的振幅的依赖性。结果进行了讨论，相对于昼夜节律的主要生理作用，这是让生物体适应其周期性变化的环境夹带自然LD周期。
Circadian rhythms occur in nearly all living organisms with a period close to 24 h. These rhythms constitute an important class of biological oscillators which present the characteristic of being naturally subjected to forcing by light-dark (LD)cycles. Tn order to investigate the conditions in which such a forcing might lead to chaos, we consider a model for a circadian limit cycle oscillator and assess its dynamic behavior when a light-sensitive parameter is periodically forced by LD cycles. We determine as a function of the forcing period and of the amplitude of the light-induced changes in the light-sensitive parameter the occurrence of various modes of dynamic behavior such as quasi-periodicity, entrainment, period-doubling and chaos. The type of oscillatory behavior markedly depends on the forcing waveform; thus the domain of entrainment grows at the expense of the domain of chaos as the forcing function progressively goes from a square wave to a sine wave. Also studied is the dependence of the phase of periodic or aperiodic oscillations on the amplitude of the light-induced changes in the control parameter. The results are discussed with respect to the main physiological role of circadian rhythms which is to allow organisms to adapt to their periodically varying environment by entrainment to the natural LD cycle.