The relative importance in the auditory nerve spiking of a neuron's internal dynamics versus an external input stimulus

Neuron spiking typically reflects both the intrinsic dynamics of the neuron as well as characteristics of extrinsic stimuli. In this paper, we compare the importance of the neuron's internal dynamics and the spectro-temporal characteristics of an input speech stimulus in a previously developed point process model for auditory nerve spiking. Using a relative deviance measure and Kolmogorov-Smirnov (KS) analysis, we show that, for low spontaneous rate neurons, the spectro-temporal characteristics of the input speech stimulus are much more important than the neuron's internal dynamics and, in fact, sufficient to explain the neuron spiking. However, for higher spontaneous rates, both are shown to be almost equally important to the spiking. The relative importance of one of these two aspects for spiking in the auditory nerve and their relevance in the neuron firing model therefore depends on the spontaneous rate of the neuron.