Cochlear nerve responses to waveform singularities and envelope corners

One way that discrete acoustic events may be signaled to the central nervous system is through spike synchrony over a subpopulation of cochlear axons. Each of the four corners of a trapezoidally modulated tone burst is such an event. Ordinarily, each corner comprises both an abrupt change in envelope slope and a singularity in the modulated waveform. In this study, in addition to stimuli of this sort, we employed a stimulus waveform in which a corner occurred without a waveform singularity. We obtained masker tuning curves for the CAPs corresponding to both kinds of corners and single-unit responses to both kinds of corners. The results suggest that the subpopulation of cochlear axons excited by the singularity component of a corner is distinct from that excited by the abrupt change in envelope slope.