Frequency dependence of tone-burst-generated whole nerve action potentials

Abstract

At high sound-pressure levels, whole nerve action potentials (AP) elicited by tone burst, have been said to be generated by the click-like action of the onset of the bursts. The contrary opinion, that the AP is frequency dependent, has also been voiced. By using high-pass noise and tone-on-tone masking, tone-burst-elicited APs can indeed be shown to be highly frequency specific. In fact, by changing the cutoff frequency of masking noise, it is demonstrated that only a specific region on the basilar membrane, corresponding to the frequency of the tone burst, contributes to AP. As the frequency of the tone burst is changed, the masking curves shift accordingly. Tone-on-tone masking confirms these results by generating curves that are similar to the ones found in human psychophysical masking experiments. These findings might prove valuable in human electrocochleography where the use of high-intensity tones is desirable for obtaining better signal-to-noise ratios. [Supported by grants from NIH.]