Effects of an improved auditory-periphery model on the response properties of modeled neurons in the Dorsal Cochlear Nucleus

Dorsal Cochlear Nucleus (DCN) neurons were simulated using two different models of auditory nerve (AN) fibers as inputs, the Carney model [1] and the Zilany & Bruce model [2], [3]. The change of AN models produced very different responses. DCN neurons simulated using the Zilany and Bruce model had much greater regions of excitation and significantly reduced regions of inhibition. Further investigation into the differences between the two AN models revealed that the broadened tuning of the auditory nerve fibers produced by the Zilany & Bruce model at higher stimulus intensities coupled with the lower excitation thresholds accounted for the discrepancies. Changes in DCN model connection parameters and their effects on the resulting simulated neurons were then explored in an attempt to provide a qualitative framework for determining a set of DCN parameters capable of reproducing physiological responses using the Zilany and Bruce AN fiber model. A mix of increased W-cell inhibition to narrow the response of type-II cells and changes in AN connection parameters to increase their excitability at higher intensities were found to be required to reproduce physiological response properties. These changes in the type-II cell response would provide adequate compensation for the increased excitation and broadened responses at higher intensities observed in DCN model P-cells.