A generalization of the FitzHugh-Nagumo model for excitability is provided
to account for salient features of Inferior Olive neurons. The base state i
s a limit cycle and excitability appears as spiking over peaks of the oscil
lations. The response of the model to various types of external stimulus is
also presented. In particular, we show the relevance of an appropriate bal
ance between amplitude and duration of the stimulus.