Stochastic impact in Fitzhugh-Nagumo neural system with time delays driven by colored noises

In this paper, stochastic behavior of FitzHugh-Nagumo neural system with two different kinds of time delays driven by colored noises is investigated. Based on the extended unified colored noise theory and the method of the probability density approximation, the Fokker-Planck equation and the steady-state probability density function are derived. Then through the two-state theory, the analytical expression of the signal-to-noise ratio (SNR) is also obtained. Finally, the effects of time delays and noise auto-correlation times in nonlinear dynamical system on the stationary probability density and the SNR are discussed respectively.