Wiener-Kernel Analysis of Responses to Noise of Chinchilla Auditory-Nerve Fibers

2005 ◽  
Vol 93 (6) ◽  
pp. 3615-3634 ◽  
Author(s):  
Alberto Recio-Spinoso ◽  
Andrei N. Temchin ◽  
Pim van Dijk ◽  
Yun-Hui Fan ◽  
Mario A. Ruggero
Keyword(s):  
Auditory Nerve ◽  
Signal To Noise Ratio ◽  
Phase Locking ◽  
Gaussian White Noise ◽  
Nerve Fibers ◽  
Second Order ◽  
First Order ◽  
Auditory Nerve Fibers ◽  
Onset Delays ◽  
Group Delays

Responses to broadband Gaussian white noise were recorded in auditory-nerve fibers of deeply anesthetized chinchillas and analyzed by computation of zeroth-, first-, and second-order Wiener kernels. The first-order kernels (similar to reverse correlations or “revcors”) of fibers with characteristic frequency (CF) <2 kHz consisted of lightly damped transient oscillations with frequency equal to CF. Because of the decay of phase locking strength as a function of frequency, the signal-to-noise ratio of first-order kernels of fibers with CFs >2 kHz decreased with increasing CF at a rate of about −18 dB per octave. However, residual first-order kernels could be detected in fibers with CF as high as 12 kHz. Second-order kernels, 2-dimensional matrices, reveal prominent periodicity at the CF frequency, regardless of CF. Thus onset delays, frequency glides, and near-CF group delays could be estimated for auditory-nerve fibers innervating the entire length of the chinchilla cochlea.

Pathophysiology of Tinnitus

1984 ◽  
Vol 93 (1) ◽  
pp. 39-44 ◽  
Author(s):  
Aage R. Møsller
Keyword(s):  
Auditory Nerve ◽  
Neural Coding ◽  
Temporal Pattern ◽  
Phase Locking ◽  
Cranial Nerves ◽  
Nerve Fibers ◽  
Complex Sounds ◽  
Ephaptic Transmission ◽  
Recent Developments ◽  
Auditory Nerve Fibers

The hypothesis is presented that certain forms of tinnitus are related to abnormal phase-locking of discharges in groups of auditory nerve fibers. Recent developments in auditory neurophysiology have shown that neural coding of the temporal pattern of sounds plays an important role in the analysis of complex sounds. In addition, it has been demonstrated that when some other cranial nerves are damaged, artificial synapses can occur between individual nerve fibers such that ephaptic transmission between nerve fibers is facilitated. Such “crosstalk” between auditory nerve fibers is assumed to result in phase-locking of the spontaneous activity of groups of neurons which in the absence of external sounds creates a neural pattern that resembles that evoked by sounds.

Nonlinear Modeling of Auditory-Nerve Rate Responses to Wideband Stimuli

2005 ◽  
Vol 94 (6) ◽  
pp. 4441-4454 ◽  
Author(s):  
Eric D. Young ◽  
Barbara M. Calhoun
Keyword(s):  
Auditory Nerve ◽  
Transfer Functions ◽  
Discharge Rate ◽  
Nonlinear Modeling ◽  
Nerve Fibers ◽  
Second Order ◽  
Spectral Processing ◽  
Spectrum Shape ◽  
Level Function ◽  
Auditory Nerve Fibers

The spectral selectivity of auditory nerve fibers was characterized by a method based on responses to random-spectrum-shape stimuli. The method models the average discharge rate of fibers for steady stimuli and is based on responses to ≈100 noise-like stimuli with pseudorandom spectral levels in 1/8- or 1/16-octave frequency bins. The model assumes that rate is determined by a linear weighting of the spectrum plus a second-order weighting of all pairs of spectrum values within a certain frequency range of best frequency. The method allows prediction of rate responses to stimuli with arbitrary wideband spectral shapes, thus providing a direct test of the degree of linearity of spectral processing Auditory-nerve fibers are shown to rely mainly on linear weighting of the stimulus spectrum; however, significant second-order terms are present and are important in predicting responses to random-spectrum shape stimuli, although not for predicting responses to noise filtered with cat head-related transfer functions. The second-order terms weight the products of levels at identical frequencies positively and the products of different frequencies negatively. As such, they model both curvature in the rate versus level function and suppressive interactions between different frequency components. The first- and second-order characterizations derived in this method provide a measure of higher-order nonlinearities in neurons, albeit without providing information about temporal characteristics.

scholarly journals Wiener Kernels of Chinchilla Auditory-Nerve Fibers: Verification Using Responses to Tones, Clicks, and Noise and Comparison With Basilar-Membrane Vibrations

2005 ◽  
Vol 93 (6) ◽  
pp. 3635-3648 ◽  
Author(s):  
Andrei N. Temchin ◽  
Alberto Recio-Spinoso ◽  
Pim van Dijk ◽  
Mario A. Ruggero
Keyword(s):  
Auditory Nerve ◽  
Characteristic Frequency ◽  
Basilar Membrane ◽  
Frequency Tuning ◽  
Nerve Fibers ◽  
Wiener Kernels ◽  
Neural Processes ◽  
Auditory Nerve Fibers ◽  
Group Delays ◽  
Membrane Vibrations

Responses to tones, clicks, and noise were recorded from chinchilla auditory-nerve fibers (ANFs). The responses to noise were analyzed by computing the zeroth-, first-, and second-order Wiener kernels (h0, h1, and h2). The h1s correctly predicted the frequency tuning and phases of responses to tones of ANFs with low characteristic frequency (CF). The h2s correctly predicted the frequency tuning and phases of responses to tones of all ANFs, regardless of CF. Also regardless of CF, the kernels jointly predicted about 77% of the features of ANF responses to “frozen” samples of noise. Near-CF group delays of kernels and signal-front delays of responses to intense rarefaction clicks exceeded by 1 ms the corresponding basilar-membrane delays at both apical and basal sites of the chinchilla cochlea. This result, confirming that synaptic and neural processes amount to 1 ms regardless of CF, permitted drawing a map of basilar-membrane delay as a function of position for the entire length of the chinchilla cochlea, a first for amniotic species.

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