Coherence resonance due to correlated noise in neuronal models

We study the regularity of noise-induced excitations in the FitzHugh-Nagumo (FHN) neuronal model subject to excitatory andinhibitory high-frequency input with and without correlations. For each value of the correlation a relative maximum of spike coherencecan be observed for intermediate noise strengths (coherence resonance). Moreover, the FHN system exhibits an absolute maximum ofcoherent spiking for intermediate values of both the noise amplitude and the strength of correlation (double coherence resonance). Theunderlying mechanisms can be explained by means of the discrete input statistics