Schematic structure of the ABR model. 500 AN fibers tuned to different CFs are individually simulated by the AN model. The summed activity, integrated across frequency, is then convolved with a UR and represents the simulated ABR to a given stimulus.
Diagram of the auditory-nerve model developed by Zilany and Bruce (2006). Reprinted from Zilany and Bruce (2006) with permission from the Acoustical Society of America (© 2006). The input to the AN model is the instantaneous pressure waveform of the stimulus in units of pascals. This waveform is bandpass filtered by a middle-ear filter. A feed-forward control path filter determines the characteristics of the main C1 filter path which is mainly active at levels below approximately 96 dB SPL. A parallel C2 filter path is mainly active at higher stimulus levels. The two filter paths are followed by a nonlinear IHC stage and a nonlinear synapse model. The output of the AN model, used in this study, is the instantaneous discharge rate obtained at the output of the synapse model.
Filter bandwidths, Q ERB, derived from the output of the C1 filter path (from Fig. 2). The dashed curve shows Q ERB estimates based on the data of Shera et al. (2002) obtained at a stimulation level of 40 dB pe SPL.
Left panel: Grand average ABR evoked by 60 dB nHL click (Elberling et al., 2010). Right panel: The derived UR function used throughout this study. This was calculated as the deconvolution of the grand average ABR and the summed neural activity pattern generated by the AN model in response to an identical click stimulus.
Simulated (solid curves) and modeled [dashed curves based on Eq. (9), dotted curve, based on Harte et al., 2009] ABR wave-V latencies as a function of tone-burst center frequency and level. Each line fitted to the empirical data of Neely et al. (1988) corresponds to one simulated level. Open symbols to the right show simulated click-evoked ABR wave-V latencies, filled symbols show Elberling et al. (2010) measured click latencies. All levels are given in dB peSPL.
Black lines: Simulated ABR wave-V amplitudes evoked by click and five chirps with different frequency-delay functions at three different stimulus levels. Gray lines: ABR wave-V amplitudes evoked by the click and five chirps (recorded by Elberling et al., 2010). All simulations are well within one standard deviation of the measured value. Note that the error bars in the figure represents one standard error.
Black lines: Simulated ABR wave-V latencies evoked by click and five chirps with different frequency-delay functions at three different stimulus levels. Gray lines: ABR wave-V latencies evoked by the click and five chirps (recorded by Elberling et al., 2010). Note that the error bars represents one standard deviation.
Tone burst stimuli used, with durations represented in ms and as number of cycles.
Values of the paired parameter, k and d, which define the delay-frequency function [Eq. (8)].
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