A Modified Hodgkin-Huxley Spiking Model with Continuous Spiking Output

We have used a modified Hodgkin and Huxley (HH) description of voltage dependent channels to model the currents involved in spike generation in the cricket cercal sensory system. We included this spiking model in a compartmental neuron model in order to obtain the correct scaling factor between the current actually injected in an experiment and the current arriving at the spiking initiating zone. After fixing the parameters for our spiking model so that we were able to match the spike shape of the real neuron, we found ourselves with a model which showed an almost continuous intensity versus rate characteristic. The rate of firing would increase smoothly from 0 as the intensity of the stimulus was increased. This is result is radically different from the typical bifurcation one finds in a traditional HH model. Our results were reminiscent of the characteristics of neurons with additional A-currents. We found that neither an additional A-current nor a consideration of sources of current noise is needed to obtain the continuous firing rate. Noise is, however, necessary to model the variability in the firing rate and therefore to investigate neural coding.