Auditory nerve encoding of high-frequency spectral information

Abstract

We have recently shown [1] that our ability to discriminate between a flat-spectrum noise and a similar noise with a high-frequency spectral notch deteriorates for levels around 70-80 dB SPL. The present paper explores an underlying physiological mechanism for this result. The hypothesis is that discriminability relies on the sensitivity of the auditory nerve to changes in the stimulus spectrum. A good correlation was found between behavioural results and sensitivity functions for two auditory nerve fibers with different dynamic ranges and with characteristic frequencies within the notch band. Although preliminary, these results suggest that the sensitivity of the auditory nerve to spectral notches is a non-monotonic function of stimulus level. © Springer-Verlag Berlin Heidelberg 2005.