【作者】 徐飞；

【导师】 张季谦；

【作者基本信息】 安徽师范大学 ， 生物物理学， 2019， 硕士

【摘要】 神经系统中大规模的离子交换和信号传输会产生复杂的电磁辐射,该电磁辐射对神经系统动力学行为的影响是不可忽略的。本文使用具有磁通变量的忆阻器模型改进了经典电突触模型,考察了神经系统内电磁辐射对其动力学行为的影响。论文首先为提高忆阻器模型在复杂网络中应用的有效性,进一步优化了忆阻器的漂移模型,发展了一种新型正弦窗口函数。仿真表明具有正弦型窗口函数的忆阻器模型表现出很好的可靠性。将新模型作为突触耦合项应用于Hopfield神经网络,并引入了电磁辐射效应作为控制参量。模拟发现该网络呈现出丰富的动力学行为,例如稳定态,周期态和混沌态。这部分工作已发表在Indian J Phys.期刊上。其次,构建忆阻突触耦合的Hindmarsh-Rose神经元系统,研究了电磁辐射下神经系统的集体行为和调节机制。模拟发现,神经系统中电磁辐射可能会引起神经元出现异常放电和异常同步放电,为进一步研究癫痫等神经系统疾病提供了新的思路。另外,当耦合系统处于同步状态时,忆阻突触的忆阻会随着神经元的放电行为变化而同时发生变化,这意味着忆阻突触可以有效地模拟生物突触的可塑性,并可以实现忆阻突触对外部刺激信号的有效记忆功能,这部分工作在Nonlinear Dyn.期刊上发表。最后,我们考察了电磁辐射效应对多层忆阻神经网络的时空动力学的影响。通过调节耦合强度和忆阻突触的参数,每层子网中都出现了相干态和非相干状态共存的奇异态,并且层间忆阻突触网络中也发现了奇异态。此外,通过讨论这种多层忆阻神经网络的层间同步行为,研究了多层网络的不同子网中奇异态的时空演化规律,这个工作也被发表在Nonlinear Dyn.期刊。本文研究结果表明,构建具有忆阻突触耦合的神经系统模型,发现系统内电磁辐射作用在调节其动力学行为中起着重要作用,这为研究神经系统相关疾病发生机制找到了新的重要思路,也为揭示人脑中神经系统的记忆行为提供了有用的线索。更多还原

【Abstract】 Large-scale ion exchange and signal transmission in the neural system will inevitably produce complex electromagnetic radiation,and the effect of this electromagnetic radiation on dynamic behavior of the neural system cannot be ignored.In this paper,we improved the electrical synapse model based on the memristor model with flux variables,and investigated the effect of electromagnetic radiation in the neural system on its dynamic behaviors.Firstly,to improve the effectiveness of memristor model in complex network,the drift model of memristor was further optimized,and a new sinusoidal window function had been developed.The simulation results show that the memristor model with sinusoidal window function has good reliability.The new model is applied to the Hopfield neural network as synapse coupling term,and electromagnetic radiation effect is introduced as control parameter.The results show that the network exhibits rich dynamic behaviors such as steady state,periodic state,chaotic state under different electromagnetic radiation parameters.The works of this part have been published in ’Indian J Phys.’.Secondly,Hindmarsh-Rose neural system with memristive synapse coupling was constructed,and the collective behavior and regulation mechanism of neural system under electromagnetic radiation are studied.The simulation shows that the complex electromagnetic radiation in theneural system may induce abnormal firing patterns in neurons and abnormal synchronous discharge in the neural system,which provides a new idea for further study of nervous system diseases such as epilepsy.In addition,when the coupled system is in the synchronization state,one can see that the varying of the memristance will simultaneously change with the firing behavior of neurons.It means that the plasticity of biological synapses could be effectively mimicked by using the memristive synapse and thus the effective memory function of the memristive synapse to the external stimulus signal may be realized.This part of work has been also published in ’Nonlinear Dyn.’.Finally,we investigate the effect of electromagnetic radiation on the spatio-temporal dynamic behavior of multilayer memristive neural networks.It is found that,by adjusting the coupled strength of electrical synapses and the parameters of memristive synapses,the coexistence behavior of coherent and incoherent states,i.e.,the chimera states,could appear in each layer.Meanwhile,The chimera states are also found in inter-layer memristive synapse network.In addition,by discussing the interlayer synchronization behavior of this multilayer memristive neural networks,the spatio-temporal consistency of the chimera states in each layer neural network is observed.The work was also published in ’Nonlinear Dyn.’.The results of this paper show that by constructing neural networkswith memristive synapse coupling,it is found that electromagnetic radiation in the system plays an important role in regulating its dynamic behavior,which may find new important ideas for studying the mechanism of diseases related to the nervous system and provide useful clues to reveal the memory behavior of the nervous system in the human brain.更多还原