Fig. 5. Measured excitation patterns (circles) obtained from two cupulae (A,B) with model fits (solid lines) for three different distances, d, of the stimulus sphere along the y-axis. (A) Distances d from bottom to top are 7, 12 and 17 mm. (B) Distances d from bottom to top are 10, 15 and 20 mm. Broken lines in both panels are fairly well intersecting the zeros of the extracellular receptor potentials (ERPs) (indicated by crosses on the equidistant x-axes) and therefore illustrate the linear widening (S; Eqn 3a) of the excitation patterns with increasing distance d.