Fig. 10.

The magnitude, rise time, and level sensitivity of the population response differs between AI and R. A: the population response (mean spike density for all significant responses) in AI is effectively monotonic (magnitude and rising slope increase with SPL), whereas the response in R rises more slowly and bears a more complex relation to sound level. Some evidence of an offset response is evident at the highest SPLs, seen as a bump in the function after 100 ms. Black bar indicates tone duration. B: same data, plotted to compare the population response between fields at 20, 40, 60, and 80 dB SPL (top to bottom panels). Mean spike density (±1 SE) is plotted for AI (black) and R (gray), with shading indicating time points at which the responses are significantly different by a Wilcoxon rank-sum test (P < 0.01). The point of significant divergence between the 2 curves is 17–18 ms from tone onset at all SPLs.