scholarly journals Phase Locking of Auditory-Nerve Fibers Reveals Stereotyped Distortions and an Exponential Transfer Function with a Level-Dependent Slope

2019 ◽  
Vol 39 (21) ◽  
pp. 4077-4099 ◽  
Author(s):  
Adam J. Peterson ◽  
Peter Heil
Keyword(s):  
Transfer Function ◽  
Auditory Nerve ◽  
Phase Locking ◽  
Nerve Fibers ◽  
Auditory Nerve Fibers

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.

Sensitivity of auditory nerve fibers to spectral notches

1993 ◽  
Vol 70 (2) ◽  
pp. 655-666 ◽  
Author(s):  
P. W. Poon ◽  
J. F. Brugge
Keyword(s):  
Transfer Function ◽  
Auditory Nerve ◽  
Discharge Rate ◽  
Free Field ◽  
Nerve Fibers ◽  
Broadband Noise ◽  
Dependent Manner ◽  
Repeated Presentation ◽  
Spontaneous Rate ◽  
Auditory Nerve Fibers

1. Listeners use direction-dependent spectral cues introduced by the torso, head, and pinnae to localize the source of a sound in space. Among the prominent direction-dependent spectral features in the free field-to-eardrum transfer function are narrow regions of low acoustic energy referred to as spectral notches. In this paper, we studied the sensitivity of single auditory nerve fibers in the barbiturate-anesthetized cat to broadband noise that had been filtered by a function whose shape approximated natural notches in the free field-to-eardrum transfer function. 2. Two experimental paradigms were employed. The first was the repeated presentation of a burst of broadband noise filtered by the simulated-notch function. Center frequency of the notch was held constant at or around the fiber characteristic frequency (CF). We refer to this as a "stationary" notch stimulus. The second paradigm was the repeated presentation of a broadband noise that was constructed from noise segments, each filtered by the simulated notch, whose CF was incremented and then decremented in a systematic way. We refer to this as a "moving" notch stimulus. Results from these two paradigms were compared with respect to notch detection. 3. Data were obtained from 161 single auditory nerve fibers having CFs ranging from 0.4 to 40 kHz. Most fibers studied had CFs > 5 kHz, and they detected the presence of the spectral notch in an intensity- and frequency-dependent manner. Each fiber responded vigorously to the presence of broadband noise. When the CF of the notch encroached on the response area of the fiber, there was a demonstrable reduction in discharge rate. The greatest reduction in discharge rate occurred when the notch was centered at the fiber's CF and when the level of the notch signal was some 15-55 dB above the fiber's noise threshold. There was close association in the frequency-intensity plane between the position of the most effective notch and the fiber's threshold tuning curve. 4. For high-spontaneous rate fibers, a moving-notch stimulus, but not a stationary one, reduced the discharge below the spontaneous rate at and in the immediate vicinity of the most effective notch frequency. This increases sensitivity to a spectral notch and suggests a mechanism by which localization ability is enhanced when there is relative motion between a sound source and the head.(ABSTRACT TRUNCATED AT 400 WORDS)

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.

scholarly journals Phase Locking of Auditory-Nerve Fibers to the Envelopes of High-Frequency Sounds: Implications for Sound Localization

2006 ◽  
Vol 96 (5) ◽  
pp. 2327-2341 ◽  
Author(s):  
Anna Dreyer ◽  
Bertrand Delgutte
Keyword(s):  
Auditory Nerve ◽  
High Frequency ◽  
Phase Locking ◽  
Discrimination Performance ◽  
Nerve Fibers ◽  
Spontaneous Discharge ◽  
Neurophysiological Studies ◽  
Pure Tones ◽  
Auditory Nerve Fibers ◽  
Psychophysical Studies

Although listeners are sensitive to interaural time differences (ITDs) in the envelope of high-frequency sounds, both ITD discrimination performance and the extent of lateralization are poorer for high-frequency sinusoidally amplitude-modulated (SAM) tones than for low-frequency pure tones. Psychophysical studies have shown that ITD discrimination at high frequencies can be improved by using novel transposed-tone stimuli, formed by modulating a high-frequency carrier by a half-wave–rectified sinusoid. Transposed tones are designed to produce the same temporal discharge patterns in high-characteristic frequency (CF) neurons as occur in low-CF neurons for pure-tone stimuli. To directly test this hypothesis, we compared responses of auditory-nerve fibers in anesthetized cats to pure tones, SAM tones, and transposed tones. Phase locking was characterized using both the synchronization index and autocorrelograms. With both measures, phase locking was better for transposed tones than for SAM tones, consistent with the rationale for using transposed tones. However, phase locking to transposed tones and that to pure tones were comparable only when all three conditions were met: stimulus levels near thresholds, low modulation frequencies (<250 Hz), and low spontaneous discharge rates. In particular, phase locking to both SAM tones and transposed tones substantially degraded with increasing stimulus level, while remaining more stable for pure tones. These results suggest caution in assuming a close similarity between temporal patterns of peripheral activity produced by transposed tones and pure tones in both psychophysical studies and neurophysiological studies of central neurons.

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