基于场耦合的神经网络放电特性影响因素

Factors affecting discharge characteristics of neural networks based on field coupling

神经网络放电特性是决定脑电位变化规律的重要因素。除化学突触作用,磁耦合对其他神经元放电特性的影响成为了近年的研究热点。然而,目前的研究只考虑放电神经元膜电流在空间产生的磁耦合,没有考虑其电学自突触电流产生的磁场作用。基于场耦合理论,充分考虑放电神经元的电学自突触电流对空间磁场的作用,根据神经元Hindmarsh-Rose(H-R)等效模型,构建仅含磁耦合作用的链式神经网络模型。通过模型研究刺激频率、距离权重、场耦合强度和电学自突触增益等因素变化对神经网络放电特性的影响规律。结果表明:①随着刺激频率从零开始增加,神经网络的放电状态呈现从“抑制”到“放电”再到“抑制”的“窗口”变化特性;②神经元网络的同步程度均随磁耦合强度和距离权重的增加而增强;③无论正、负反馈,放电神经元的电学自突触作用均能改变神经元网络的放电特性,其中正反馈的影响更显著;④电学自突触增益大于零时,同步程度随增益增大而提高。研究结果进一步表明磁耦合是实现神经元之间信号传递的一个重要方式,其中电学自突触电流的磁耦合作用不可忽视。说明神经突触的化学作用如果失效,由放电神经元膜电流和其电自学突触电流共同产生的磁场也可能引起其他神经元膜电位超过阈值而放电。

The discharge characteristics of neural network are important factors that determine the variation of brain potential.In addition to chemical synapses,the effect of magnetic coupling on the discharge characteristics of other neurons has become a research hotspot in recent years.However,previous studies have only considered the spatial magnetic coupling of the membrane current of the firing neurons without considering the magnetic field effect of the current from the electrical autaptic.In this paper,based on the field coupling theory,the effect of electrical autaptic current of firing neurons on the spatial magnetic field is fully taken into consideration.According to the Hindmarsh Rose(H-R)equivalent model of neurons,a chain-type neural network model with magnetic coupling is constructed.The effects of stimulus frequency,distance weight,field coupling intensity and electrical autaptic gain on the discharge characteristics of the neural network are studied by the model.The results show that:①With the increase of stimulus frequency from zero,the discharge state of the neural network changes from“inhibition”to“discharge”and then to“inhibition”.②The degree of synchronization of neural networks intensifies with the increase of magnetic coupling strength and distance weight.③The electrical autaptic of the firing neurons can change the firing characteristics of the neuronal network regardless of the positive feedback and negative feedback,but the positive feedback has more significant effect.④When the electrical autaptic gain is greater than zero,the degree of synchronization increases with the increase of the gain.The results further show that magnetic coupling is an important way to realize signal transmission between neurons,and the magnetic coupling effect of electrical autaptic current cannot be ignored.This suggests that if the chemical action of the synapse fails,the magnetic field generated by the membrane current of the firing neuron and its electrical autaptic current may also cause the membrane potential of other neurons to discharge over the threshold value.