Discussion and Relevance of the Findings to Cochlear Activity

We observed neural response in the supra-CF plateau region. Neural plateau (gerbil) is at least 10~15 dB higher than BM plateau (chinchilla). 1. Gerbil BM data is usually in the high-BF region. We lack high-CF AN units to compare at this point. 2. Windowing problem: it is possible that the synaptic/neural delay is not correctly accounted for. ie. spikes during a tone-on period are mistaken for a tone-off period. This problem would lead to false positive threshold attainment. However, this problem is eliminated by monitoring overall firing rate increase with the use of rate level functions. 3. Spectral splatter problem: on ramp/off ramp in the stimulus envelope introduce frequencies other than the stimulus itself. It is conceivable that this frequency splatter could cause spurious transient response. This can be mostly avoided by a) inspecting raster plots to identify the transient response, 2) using only the steady-state response, 3) monitoring firing rates. (see Methods) 4. It is possible for the high SPL stimuli to cause AN threshold shift and/or hearing damage. 5. Subharmonics could be the source of the AN plateau response. AN units have a lower threshold (near CF) at subharmonics frequencies of the stimulus. (see Future Studies) 6. The BM motion data acquired by Laser measurement could be contaminated by the round windo