A, Typical responses of IN neurons during on-axis neck rotations about the C1–C2 axis (left, PNR) and off-axis neck flexion about the C6–T3 axis (right, EVA-PNR). Shown are the responses during 2 Hz rotations (±10°/s) for a canal-only (top), otolith-only (middle), and canal–otolith neuron (bottom). Traces shown include neck angular velocity (solid trace) and unit discharge rate (histogram). Fits for estimating the unit's gain and phase are shown superimposed on the unit's discharge rate. The neurons illustrated here are the same as in Figure 3. B, Summary of the IN neuron response properties during axial PNRs and lateral neck flexion (EVA-PNR). Left, A polar plot summarizing the gain and phase characteristics of neuron responses during PNR as a function of unit type. Right, A polar plot summarizing the gain and phase characteristics of neuron responses during EVA-PNR as a function of unit type. Filled (ipsilateral sensitive) and open (contralateral sensitive) symbols in all plots denote the unit's vestibular sensitivity.