FIG. 8.

There are two parameters of spiral ganglion neuron phenotypic specializations that vary along the tonotopic map. The first represented by the timing of the musical notes at the tips of the neuronal tuning curves is the kinetic features of the neurons at thresholds that vary in a linear gradient. The second represented by the shape of the neuronal cluster shown in the background (gray, stained with anti-β-tubulin antibody) and the U-shaped scale bar is the non-monotonic neuronal sensitivity. The most sensitive neurons (red within the mid-apical region) have elevated resting membrane potentials and enhanced excitability due to reduced threshold voltages.