Ratio of variance to mean of action potential counts for an auditory nerve fiber model with second-order refractory behavior.

Sequences of interval times were generated with the first- and second-order interval probability dependence proposed by Gaumond et al. [J. Neurophysiol. 48, 856-873 (1982)] to characterize cochlear nerve fiber spontaneous action potential (AP) sequences. The ratio F(T) of the variance to the mean of the count of APs in bins of T s was computed for the simulated sequences, and compared to the corresponding measure for cochlear nerve fiber data presented by Lowen and Teich [J. Acoust. Soc. Am. 92, 803-806 (1992)]. The simulations were generally consistent with the data in the range 15 < T < 100 ms.