In order to treat the effect of subthreshold dynamics on noisy neuron behavior we focus on parameters region of FitzHugh-Nagumo
model close to the so called canard-explosion. Such parameter region corresponds to transition from excitable regime to continuous spiking. We observe the number of noise-induced effects, such as (i) noise-induced stabilization of firing frequency; (ii) noise-induced
suppression of spiking; (iii) noise-induced chaos. We show that for small ensemble of resonator-type neurons activated by noise there is the global maxima of firing frequency at some optimal noise intensity. The underlying mechanisms of such behavior are closely related to noise-activated subthreshold dynamics.