Excitable dynamical systems

Excitability, i.e., a large-amplitude response to a super- threshold perturbation while a sub-threshold perturbation leaves the system almost unchanged, is the key property of neural cells of the retina of human eye. Basic terms are introduced and the dynamic behavior under single-pulse and under periodic perturbation is discussed in detail using the firing ratio as a function of the perturbation amplitude and of the perturbation period forming a 'devil staircase' structure.