Suppression in auditory-nerve fibers of cats using low-side suppressors. II. Effect of spontaneous rates

The responses of auditory nerve fibers with different spontaneous rates were studied in anesthetized cats, using harmonically related characteristic frequency (CF) tone and suppressor (SUP) tone (50-2000 Hz) as stimuli. The relative-response index, defined as the ratio of the maximum response level in the two-tone segment to the response level in the CF-alone segment, at or near the intensity of maximum suppression (i.e., where the two-tone rate was lowest), was dependent on fiber's spontaneous rate (SR). For all the SUP frequencies used, lower-SR fibers almost always showed values less than unity, while high-SR fibers almost always gave values near or greater than unity. The phase of maximum suppression was not dependent upon fiber SR. In one experiment, a pair of low- and high-SR fibers with the same CF (12 kHz) were recorded consecutively in the same electrode penetration, and were studied with the same stimulus parameters. Their temporal responses showed dramatic temporal resemblances, with very similar phases of suppression and response. But the relative-response indexes were different. The similarities in the lower- and high-SR fibers support the idea that the basic response and suppression patterns in all fibers are formed at or before the inner hair cell (IHC) stage, while the differences suggest that processes more central than the IHC receptor potential are important in determining the magnitudes of suppression, particularly in the lower-SR fibers.

[1]  M. Sachs.  Stimulus-response relation for auditory-noise fibers: two-tone stimuli. , 1969, The Journal of the Acoustical Society of America.

[2]  A model proposing synaptic and extra-synaptic influences on the responses of cochlear nerve fibres , 1989, Hearing Research.

[3]  William S. Rhode,et al.  Two-tone suppression and distortion production on the basilar membrane in the hook region of cat and guinea pig cochleae , 1993, Hearing Research.

[4]  C. Daniel Geisler,et al.  Saturation of outer hair cell receptor currents causes two-tone suppression , 1990, Hearing Research.

[5]  Effects of altering organ of Corti on cochlear distortion products f2 - f1 and 2f1 - f2. , 1982, Journal of neurophysiology.

[6]  A R Cody,et al.  Transfer characteristic of the inner hair cell synapse: steady-state analysis. , 1994, The Journal of the Acoustical Society of America.

[7]  J. Doucet,et al.  Recovery from prior stimulation. I: Relationship to spontaneous firing rates of primary auditory neurons , 1991, Hearing Research.

[8]  C. Daniel Geisler,et al.  Temporal patterns of the responses of auditory-nerve fibers to low-frequency tones , 1996, Hearing Research.

[9]  B. M. Johnstone,et al.  Modulation of responses of spiral ganglion cells in the guinea pig cochlea by low frequency sound , 1982, Hearing Research.

[10]  C. Geisler,et al.  Long-term suppression of the responses of auditory nerve fibers to a characteristic-frequency tone by a low-frequency suppressor , 1996, Hearing Research.

[11]  P. Sellick,et al.  The responses of inner hair cells to basilar membrane velocity during low frequency auditory stimulation in the guinea pig cochlea , 1980, Hearing Research.

[12]  P Dallos,et al.  Comparison of low- and high-side two-tone suppression in inner hair cell and organ of corti responses , 1990, Hearing Research.

[13]  M. Liberman.  Morphological differences among radial afferent fibers in the cat cochlea: An electron-microscopic study of serial sections , 1980, Hearing Research.

[14]  N. Kiang,et al.  Hair-cell innervation by spiral ganglion cells in adult cats. , 1982, Science.

[15]  M. Cheatham,et al.  Physiological correlates of off-frequency listening , 1992, Hearing Research.

[16]  M. Liberman,et al.  Auditory-nerve response from cats raised in a low-noise chamber. , 1978, The Journal of the Acoustical Society of America.

[17]  Bertrand Delgutte,et al.  Two-tone rate suppression in auditory-nerve fibers: Dependence on suppressor frequency and level , 1990, Hearing Research.

[18]  IJ Russell,et al.  Modulation of hair cell voltage responses to tones by low-frequency biasing of the basilar membrane in the guinea pig cochlea , 1992, The Journal of neuroscience : the official journal of the Society for Neuroscience.

[19]  W. S. Rhode,et al.  Characteristics of tone-pip response patterns in relationship to spontaneous rate in cat auditory nerve fibers , 1985, Hearing Research.

[20]  M. Cheatham,et al.  Stimulus biasing: A comparison between cochlear hair cell and organ of corti response patterns , 1994, Hearing Research.

[21]  M. Liberman.  Single-neuron labeling in the cat auditory nerve. , 1982, Science.

[22]  C D Geisler,et al.  Thresholds for primary auditory fibers using statistically defined criteria. , 1985, The Journal of the Acoustical Society of America.

[23]  Two-tone suppression, excitation and the after effect in rate responses in auditory nerve fibres in the cat , 1992, Hearing Research.

[24]  Alfred L. Nuttall,et al.  Inner hair cell responses to the velocity of basilar membrane motion in the guinea pig , 1981, Brain Research.

[25]  R. A. Schmiedt.  Boundaries of two-tone rate suppression of cochlear-nerve activity , 1982, Hearing Research.

[26]  P J Abbas,et al.  Two-tone suppression in auditory-nerve fibers: extension of a stimulus-response relationship. , 1976, The Journal of the Acoustical Society of America.

[27]  A. R. Palmer,et al.  Time course of rate responses to two-tone stimuli in auditory nerve fibres in the guinea pig , 1991, Hearing Research.

[28]  C. Geisler,et al.  Suppression in auditory-nerve fibers of cats using low-side suppressors. I. Temporal aspects , 1996, Hearing Research.

[29]  M. A. Cheatham,et al.  Two-tone suppression in inner hair cell responses: Correlates of rate suppression in the auditory nerve , 1992, Hearing Research.

[30]  A. Nuttall,et al.  Two-tone suppression of inner hair cell and basilar membrane responses in the guinea pig. , 1993, The Journal of the Acoustical Society of America.

[31]  B. M. Johnstone,et al.  The modulation of the sensitivity of the mammalian cochlea by low frequency tones. I. Primary afferent activity , 1984, Hearing Research.

[32]  L. Robles,et al.  Two-tone suppression in the basilar membrane of the cochlea: mechanical basis of auditory-nerve rate suppression. , 1992, Journal of neurophysiology.

[33]  G. K. Yates,et al.  Cochlear nerve fiber responses to amplitude-modulated stimuli: variations with spontaneous rate and other response characteristics. , 1993, Journal of neurophysiology.

[34]  J. Allen,et al.  Nonlinear phenomena as observed in the ear canal and at the auditory nerve. , 1985, The Journal of the Acoustical Society of America.