scholarly journals The Temporal Relationship Between Motion of the Basilar Membrane and Initiation of Nerve Impulses in the Auditory Nerve Fibers

1973 ◽  
Vol 53 (1) ◽  
pp. 325-325 ◽  
Author(s):  
T. Konishi ◽  
D. W. Nielsen
Keyword(s):  
Auditory Nerve ◽  
Temporal Relationship ◽  
Basilar Membrane ◽  
Nerve Fibers ◽  
Nerve Impulses ◽  
Auditory Nerve Fibers

scholarly journals Threshold Tuning Curves of Chinchilla Auditory-Nerve Fibers. I. Dependence on Characteristic Frequency and Relation to the Magnitudes of Cochlear Vibrations

2008 ◽  
Vol 100 (5) ◽  
pp. 2889-2898 ◽  
Author(s):  
Andrei N. Temchin ◽  
Nola C. Rich ◽  
Mario A. Ruggero
Keyword(s):  
Auditory Nerve ◽  
Basilar Membrane ◽  
Frequency Tuning ◽  
Nerve Fibers ◽  
Lower Limbs ◽  
Gradual Transition ◽  
Characteristic Frequencies ◽  
Tuning Curves ◽  
Auditory Nerve Fibers ◽  
Threshold Tuning

Frequency-threshold tuning curves were recorded in thousands of auditory-nerve fibers (ANFs) in chinchilla. Synthetic tuning curves with 21 characteristic frequencies (187 Hz to 19.04 kHz, spaced every 1/3 octave) were constructed by averaging individual tuning curves within 2/3-octave frequency bands. Tuning curves undergo a gradual transition in symmetry at characteristic frequencies (CFs) of 1 kHz and an abrupt change in shape at CFs of 3–4 kHz. For CFs ≤3 kHz, the lower limbs of tuning curves have similar slopes, about −18 dB/octave, but the upper limbs have slopes that become increasingly steep with increasing frequency and CF. For CFs >4 kHz, tuning curves normalized to the CF are nearly identical and consist of three segments. A tip segment, within 30–40 dB of CF threshold, has lower- and upper-limb slopes of −60 and +120 dB/octave, respectively, and is flanked by a low-frequency (“tail”) segment, with shallow slope, and a terminal high-frequency segment with very steep slope (several hundreds of dB/octave). The tuning curves of fibers innervating basal cochlear sites closely resemble basilar-membrane tuning curves computed with low isovelocity criteria. At the apex of the chinchilla cochlea, frequency tuning is substantially sharper for ANFs than for available recordings of organ of Corti vibrations.

Biomechanics of Hearing Sensitivity

1991 ◽  
Vol 113 (1) ◽  
pp. 1-13 ◽  
Author(s):  
Sir James Lighthill
Keyword(s):  
Hair Cells ◽  
Auditory Nerve ◽  
Basilar Membrane ◽  
Nerve Fibers ◽  
Outer Hair Cells ◽  
Hearing Sensitivity ◽  
Sound Levels ◽  
Auditory Nerve Fibers ◽  
The Brain ◽  
Stiffness Distribution

This survey lecture on the biomechanics of hearing sensitivity is concerned, not with how the brain in man and other mammals analyzes the data coming to it along auditory nerve fibers, but with the initial capture of that data in the cochlea. The brain, needless to say, can produce all its miracles of interpretation only where it works on good initial data. For frequency selectivity these depend on some remarkable properties of the cochlea as a passive macromechanical system, comprising the basilar membrane with its steeply graded stiffness distribution vibrating within the cochlear fluids. But the biomechanics of hearing sensitivity to low levels of sound (at any particular frequency) calls also into play an active micromechanical system, which during the past few years has progressively been identified as located in the outer hair cells, and which, through a process of positive feedback, amplifies (in healthy ears) that basilar membrane vibration. This in turn offers the inner hair cells an enhanced signal at low sound levels, so that the threshold at which they can generate activity in auditory nerve fibers is, in consequence, very substantially lowered.

scholarly journals Threshold Tuning Curves of Chinchilla Auditory Nerve Fibers. II. Dependence on Spontaneous Activity and Relation to Cochlear Nonlinearity

2008 ◽  
Vol 100 (5) ◽  
pp. 2899-2906 ◽  
Author(s):  
Andrei N. Temchin ◽  
Nola C. Rich ◽  
Mario A. Ruggero
Keyword(s):  
Spontaneous Activity ◽  
Auditory Nerve ◽  
Characteristic Frequency ◽  
Basilar Membrane ◽  
Frequency Tuning ◽  
Nerve Fibers ◽  
Nonmonotonic Dependence ◽  
Tuning Curves ◽  
Auditory Nerve Fibers ◽  
Threshold Tuning

Spontaneous activity and frequency threshold tuning curves were studied in thousands of auditory nerve fibers in chinchilla. The frequency distribution of spontaneous activity rates is strongly bimodal for auditory nerve fibers with characteristic frequency <3 kHz but only mildly bimodal for the entire sample. Spontaneous activity rates and thresholds at the characteristic frequency are inversely related. Auditory-nerve fibers with low spontaneous rate have tuning curves with lower tip-to-tail ratios and more sharply tuned tips than the tuning curves of fibers with high spontaneous rates. It is shown here that this dependence of tuning on spontaneous rates is consistent with a previously unnoticed nonmonotonic dependence on iso-velocity criterion of the frequency tuning of basilar membrane vibrations.

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