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 and
inhibitory high-frequency input with and without correlations. For each value of the correlation a relative maximum of spike coherence
can be observed for intermediate noise strengths (coherence resonance). Moreover, the FHN system exhibits an absolute maximum of
coherent spiking for intermediate values of both the noise amplitude and the strength of correlation (double coherence resonance). The
underlying mechanisms can be explained by means of the discrete input statistics