Fig. 11.

Simulation of a central gain change after impairment that normalizes total AN activity at high sound levels. The summed AN data from Figures 8 and 10 were recomputed by normalizing the impaired population responses to match the saturated normal response at 95 dB SPL (solid lines). The dotted lines show the same calculation when the three highest BF channels are deleted. (A, B) The renormalized summed responses for the entire-population calculations from Figure 8, with the same conventions used as in Figure 8C and B. (C, D) The renormalized summed responses for the 2-kHz BF channel calculations from Figure 10. The mild-loss case without high BFs (thicker dotted line in A and B) provides an example of how recruitment-like effects can be produced by a change in central gain to overcome reduced peripheral activity. However, in all other cases, the renormalization does not alleviate the discrepancy between summed AN activity and recruitment.