Auditory Nerve Encoding of High-Frequency Spectral Information

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.

[1]  N Suga,et al.  Properties of ‘two‐tone inhibition’ in primary auditory neurones , 1971, The Journal of physiology.

[2]  Bradford J. May.  Physiological and psychophysical assessments of the dynamic range of vowel representations in the auditory periphery , 2003, Speech Commun..

[3]  R. Butler,et al.  Spectral cues utilized in the localization of sound in the median sagittal plane. , 1977, The Journal of the Acoustical Society of America.

[4]  B. Delgutte,et al.  Speech coding in the auditory nerve: III. Voiceless fricative consonants. , 1984, The Journal of the Acoustical Society of America.

[5]  L. Carney,et al.  A phenomenological model for the responses of auditory-nerve fibers: I. Nonlinear tuning with compression and suppression. , 2001, The Journal of the Acoustical Society of America.

[6]  M. Sachs,et al.  Rate versus level functions for auditory-nerve fibers in cats: tone-burst stimuli. , 1974, The Journal of the Acoustical Society of America.

[7]  B. Delgutte,et al.  A Physiologically Based Model of Interaural Time Difference Discrimination , 2004, The Journal of Neuroscience.

[8]  D. M. Green,et al.  Signal detection theory and psychophysics , 1966 .

[9]  R. Humanski,et al.  Localization of sound in the vertical plane with and without high-frequency spectral cues , 1992, Perception & psychophysics.

[10]  Ian M. Winter,et al.  Diversity of characteristic frequency rate-intensity functions in guinea pig auditory nerve fibres , 1990, Hearing Research.

[11]  E. Young,et al.  Auditory-nerve encoding of pinna-based spectral cues: rate representation of high-frequency stimuli. , 1995, The Journal of the Acoustical Society of America.

[12]  D. H. Johnson,et al.  The relationship between spike rate and synchrony in responses of auditory-nerve fibers to single tones. , 1980, The Journal of the Acoustical Society of America.

[13]  J. Brugge,et al.  Sensitivity of auditory nerve fibers to spectral notches. , 1993, Journal of neurophysiology.

[14]  A Robert,et al.  A composite model of the auditory periphery for simulating responses to complex sounds. , 1999, The Journal of the Acoustical Society of America.

[15]  Ray Meddis,et al.  A revised model of the inner-hair cell and auditory-nerve complex. , 2002, The Journal of the Acoustical Society of America.

[16]  J. Hebrank,et al.  Spectral cues used in the localization of sound sources on the median plane. , 1974, The Journal of the Acoustical Society of America.

[17]  Enrique A. Lopez-Poveda,et al.  Detection of high-frequency spectral notches as a function of level , 2003 .

[18]  E. F. Evans,et al.  Relationship between the dynamic range of cochlear nerve fibres and their spontaneous activity , 2004, Experimental Brain Research.

[19]  M. Sachs,et al.  Encoding of steady-state vowels in the auditory nerve: representation in terms of discharge rate. , 1979, The Journal of the Acoustical Society of America.