FitzHugh―Nagumo神经元模型非阈下响应的随机共振

研究了当FitzHugh-Nagumo(FHN)神经元模型在弱信号激励下只有阈上振荡响应时的随机共振。研究结果表明:随着FHN神经元模型的分岔参数的增加,发生了一个由两个吸引子(阈上振荡和阈下振荡)变化到一个吸引子(阈上振荡)的分岔;当FHN神经元模型的分岔参数位于分岔点的右边时,在弱信号激励下系统的响应只有阈上振荡存在,此时在外噪声或者内噪声的调制下,系统响应的能量向输入信号频率处集中,而信噪比随噪声强度的变化曲线呈现出单峰曲线,随机共振发生了,并且此时随机共振发生的机制是由于系统运动在分岔点左右三个吸引子(两个在分岔前一个在分岔后)之间的跃迁而产生的。

Stochastic Resonance of Non-sub-threshold Response of FHN Neuron Model

In this paper stochastic resonance of FHN neuron model when there exists only the response of suprathreshold oscillation with weak periodic signal is studied.The results of research show: A bifurcation of transition from two attractors(suprathreshold oscillation and sub-threshold oscillation) to one attractor(suprathreshold oscillation) occurs with the increase of bifurcation parameter,when the bifurcation parameter of system is on the right side of bifurcation point there exists only the response of suprathreshold oscillation in FHN neuron model excited by weak signal,in this case,under the modulation of external noise or internal noise,the energy of system response concentrating on the frequency of input signal,and the curve of signal-noise-ratio(SNR) of system response vs noise extensity is a mon-peak curve,stochastic resonance occurs,and the mechanism of stochastic resonance in this case is related to the transitions among the three attractors(two before bifurcation and one after it) on the left and right sides of bifurcation point.