A MATHEMATICAL-MODEL OF THE HUMAN CIRCADIAN SYSTEM AND ITS APPLICATION TO JET-LAG

被引:15
作者
GUNDEL, A
SPENCER, MB
机构
[1] DLR-Institute for Aerospace Medicine, Cologne
[2] Royal Air Force Institute of Aviation Medicine, Farnborough
关键词
MATHEMATICAL MODEL; VANDERPOL OSCILLATOR; CIRCADIAN REGULATION; JET LAG;
D O I
10.3109/07420529209064526
中图分类号
Q [生物科学];
学科分类号
07 ; 0710 ; 09 ;
摘要
A mathematical model of the circadian system is described that is appropriate for application to jet lag. The core of the model is a van der Pol equation with an external force. Approximate solutions of this equation in which the external force is composed of a constant and an oscillating term are investigated. They lead to analytical expressions for the amplitude and period of free-running rhythms and for the frequency limits of the entrainment region. The free-running period increases quadratically with stiffness. Both period and amplitude depend on the value of the constant external force. The width of the range of entrainment is mostly determined by the external force, whereas the relative position of this range follows the intrinsic period of the oscillator. Experiments with forced and spontaneous internal desynchronization were evaluated using these analytical expressions, and estimates were obtained for the intrinsic period of the oscillator, its stiffness, and the external force. A knowledge of these model parameters is essential for predictions about circadian dynamics, and there are practical implications for the assessment of the adaptation after rapid transmeridian travel.
引用
收藏
页码:148 / 159
页数:12
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