Analysis Of Mammalian Circadian Clock At The Level Of Single Cell And Multicellular

The main clock of mammalian is located on the Suprachiasmatic Nucleus,which contains 20000 neuron oscillators with different internal periods.According to the different regions of Suprachiasmatic Nucleus producing different polypeptide neurons,Suprachiasmatic Nucleus is anatomically divided into ventrolateral neurons and dorsomedial neurons.There is no rhythm in the expression of circadian clock genes in ventrolateral neurons.However,the expression of circadian clock gene in dorsal neurons is rhythmic,and the neurons in ventrolateral and dorsal are coupled through neurotransmitters.And the topological structure of the coupling mode will affect the period of mammalian clock and the synchronization behavior between neuron oscillators.In some existing studies,we discussed that the coupling mode can be considered by using the knowledge of complex networks,based on this,this paper analyzed the periodic behavior and synchronization behavior among the neurons oscillators in four different coupling modes.These four coupling modes are All-to-All fully connected networks,Newman-Watts Small World Networks,Barab?asi-Albert scale-free networks,Erd?os-Re?nyi random networks.Based on the modified Goodwin model,this paper analyzed the dynamic behavior of mammalian circadian clock at single cell level and found that the maximum generation rate affects the dynamic behavior of mammalian single neuron oscillator through numerical simulation.In addition,this paper also found the light intensity can not only lower the threshold of the maximum generation rate that oscillates the single neuron oscillator of the mammal,but also increase the range of the maximum generation rate when the period of a single neuron oscillator of the mammal is consistent with the external cycle.Based on the coupled neuron oscillators model,this paper analyzed the dynamic behavior of mammalian circadian clock at multicellular level.The result showed that weak light intensity is beneficial to the synchronization of weakly coupled neuron oscillators,and when there is light,neuron oscillators are coupled by the generation method of NW small world networks is more prone to synchronization than by the generation method of All-to-All networks,BA networks,ER networks.In addition,this paper also analyzed the effect of light duration on the synchronization behavior of coupled neuron oscillators.The result showed that when the coupling mode and light intensity of the neuron oscillatorare constant,The synchronization degree of neuron oscillators under the light duration of less than 12 h is higher than under 12h:12h light duration and greater than 12 h light duration.To make the result more general,we analyzed the topology of the coupling modes.The analysis result show that the topology of the coupling modes do not change this conclusion.