Cardoso Francisco Roberto Gomes, de Oliveira Cruz Frederico Alan, Silva Dílson, Cortez Célia Martins
Department of Physiological Sciences, Rio de Janeiro State University, Rio de Janeiro, Brazil.
Biol Cybern. 2009 May;100(5):385-93. doi: 10.1007/s00422-009-0309-6. Epub 2009 Apr 15.
This paper presents a model for the circadian temporization system of mammals which associates the synchronization dynamics of coupling oscillators to a set of equations able to reproduce the synaptic characteristics of somatodendritic membrane of neurons. The circadian timing system is organized in a way to receive information from the external and internal environments, and its function is the timing organization of physiological and behavioral processes in a circadian pattern. Circadian timing system in mammals is constituted by a group of structures which includes the suprachiasmatic nucleus, the intergeniculate leaflet and the pineal gland. In suprachiasmatic nucleus are found neuron groups working as a biological pacemaker-the so-called biological master clock. By means of numerical simulations using the Kuramoto model, we simulated the dynamics behavior of the biological pacemaker. For this we used a set of 1,000 coupled oscillators with long-range coupling, which were distributed on a 10 x 10 x 10 spherical lattice, and a new method to estimate the order parameter, which characterizes the degree of synchronization of oscillator system. Our model has been able to produce frequency responses in accordance with physiological patterns, and to reproduce two fundamental characteristics of biological rhythms: the endogenous generation and synchronization to the light-dark cycle.
本文提出了一种哺乳动物昼夜节律定时系统模型，该模型将耦合振荡器的同步动力学与一组能够再现神经元体树突膜突触特征的方程相关联。昼夜节律定时系统以一种接收来自外部和内部环境信息的方式组织起来，其功能是以昼夜节律模式对生理和行为过程进行定时组织。哺乳动物的昼夜节律定时系统由一组结构组成，包括视交叉上核、膝间小叶和松果体。在视交叉上核中发现了作为生物起搏器工作的神经元群——即所谓的生物主时钟。通过使用Kuramoto模型进行数值模拟，我们模拟了生物起搏器的动力学行为。为此，我们使用了一组1000个具有长程耦合的耦合振荡器，它们分布在一个10×10×10的球形晶格上，以及一种估计序参量的新方法，该序参量表征了振荡器系统的同步程度。我们的模型能够产生符合生理模式的频率响应，并再现生物节律的两个基本特征：内源性产生和与明暗周期同步。
