基于抑制性反馈的神经元放电频率适应性调控机制研究

Study on Adaptive Regulation Mechanism of Neuronal Firing Frequency Based on Inhibitory Feed-back

目的探究基于抑制性反馈机制的神经元放电频率适应性,以解决反馈结构在神经元放电频率适应性调控中的作用。方法构建抑制性反馈神经回路模型,采用基于电导的LIF神经元模型;定义响应敏感度、适应精度两个评价指标定量描述反馈结构对神经元放电频率适应性的调控规律,利用MAT-LAB进行仿真分析。结果输入为100 pA时,反馈连接强度在1到4的范围内,随着反馈回路时间参数的增加,神经元适应性范围以及敏感度和精度值逐渐增加;反馈回路时间参数为5 ms时,随着输入强度的增加,神经元产生适应性放电的反馈连接强度和反馈回路参数区域随之右移,敏感度和精度值逐渐减小。结论当抑制性反馈连接强度在1~4的范围以及反馈回路时间参数在4~10ms范围内时,兴奋性神经元在抑制性反馈作用下会呈现出较明显的放电频率适应性特征,表明抑制性反馈是神经元放电适应性的一种重要机制。

Objective To explore the neural firing frequency adaptability based on inhibitory feedback mechanism,so as to solve the important role of feedback structure in the regulation of neural firing frequency adaptability.Methods An inhibitory feedback neural loop model was constructed and the LIF(leaky integrate and-fire)neuron model based on conductance was adopted.Two evaluation inde-xes were defined including the response sensitivity and the adaptive precision to describe the regulation of feedback structure on the spike-frequency adaptation.Then simulation analysis was carried out with MATLAB.Results When the input was 100 pA,the feedback connection strength was in the range of 1 to 4,with the increase of feedback loop time parameters,the adaptive range and the sensitivity and accuracy value of the neuron increased gradually;when the feedback loop time parameter was 5ms,with the increase of input strength,the feedback connection strength and the feedback loop parameter area of the neuron generating adaptive discharge moved right,the sensitivity and accuracy value de-creased gradually.Conclusion When the inhibitory feedback connection strength was in the range of 1 to 4 and the feedback loop time parameters were in the range of 4 to 10 ms,the excitatory neuron a-chieved obvious spike frequency adaptation under the regulation of inhibitory feedback.Furthermore,the two sides interacted to synergistically regulate the spike frequency adaptation,indicating that in-hibitory feedback was an important mechanism of spike frequency adaptation of the neurons.