"Neuronal responses are often characterized by the
firing rate as a function of the stimulus mean, or the f–I curve.
We introduce a novel classification of neurons into Types A,
B−, and B+ according to how f–I curves are modulated by
input fluctuations. ..."
Lundstrom BN, Famulare M, Sorensen LB, Spain WJ, Fairhall AL (2009) Sensitivity of firing rate to input fluctuations depends on time scale separation between fast and slow variables in single neurons J Comput Neurosci