Time of spike initiation in the auditory nerve in relation to basilar membrane motion

1982 ◽  
Vol 71 (S1) ◽  
pp. S17-S17 ◽  
Author(s):  
Mario A. Ruggero ◽  
Nola Cofer Rich
Keyword(s):  
Auditory Nerve ◽  
Basilar Membrane ◽  
Spike Initiation

Late Waves in the Response Recorded from the Intracranial Portion of the Auditory Nerve in Humans

1993 ◽  
Vol 102 (12) ◽  
pp. 945-953 ◽  
Author(s):  
Aage R. Møller
Keyword(s):  
Auditory Nerve ◽  
High Frequency ◽  
Basilar Membrane ◽  
Opposite Polarity ◽  
Surgical Trauma ◽  
Moderate Degree ◽  
Speech Discrimination ◽  
Eighth Nerve ◽  
Pure Tone Threshold ◽  
Click Polarity

We showed in previous studies that the click-evoked responses from the exposed eighth nerve in some patients contain quasiperiodic components that appear in the interval between 4 and 16 milliseconds after the click stimulus, and that the phase of these oscillatory components reverses when the click polarity is reversed. When the responses to clicks of opposite polarity are subtracted from each other, these late waves appear as a prolonged quasiperiodic oscillation with a frequency around 700 Hz. These late components appear more frequently in patients with high-frequency hearing losses than in patients with normal hearing. We have attributed these components to prolonged and in-phase oscillations of a large portion of the basilar membrane, possibly caused by the generation of standing waves on the basilar membrane. The results of the present study show that these oscillations correspond closely in both frequency and phase to the late oscillations that are seen in the cross-correlograms of the responses from the exposed eighth nerve to pseudorandom noise. The finding that similar quasiperiodic components can be retrieved from the responses from the exposed eighth nerve to both transient and continuous sounds is taken as an indication that the neural activity that these components represent reflects some general property of the cochlear frequency analyzer. We also found that the speech discrimination is not noticeably different in patients with such waves compared with what it is in patients with similar hearing loss who do not have such waves. This is taken as an indication that spectral analysis in the cochlea is less important in speech discrimination than previously assumed. The importance of timing of auditory nerve activity for speech perception is indicated by the finding that surgical trauma of the intracranial portion of the auditory nerve that only causes a moderate degree of deterioration of the pure tone threshold reduces speech discrimination scores to zero.

scholarly journals Basilar membrane responses to two-tone and broadband stimuli

1992 ◽  
Vol 336 (1278) ◽  
pp. 307-315 ◽  
Keyword(s):  
Auditory Nerve ◽  
Basilar Membrane ◽  
Stimulus Frequency ◽  
Cell Receptor ◽  
Outer Hair Cells ◽  
Intermodulation Distortion ◽  
Mechanical Responses ◽  
Distortion Products ◽  
Cochlear Neurons ◽  
Rate Suppression

The responses to sound of mammalian cochlear neurons exhibit many nonlinearities, some of which (such as two-tone rate suppression and intermodulation distortion) are highly frequency specific, being strongly tuned to the characteristic frequency (CF) of the neuron. With the goal of establishing the cochlear origin of these auditory-nerve nonlinearities, mechanical responses to clicks and to pairs of tones were studied in relatively healthy chinchilla cochleae at a basal site of the basilar membrane with CF of 8-10 kHz. Responses were also obtained in cochleae in which hair cell receptor potentials were reduced by systemic furosemide injection. Vibrations were recorded using either the Mossbauer technique or laser Doppler-shift velocimetry. Responses to tone pairs contained intermodulation distortion products whose magnitudes as a function of stimulus frequency and intensity were com parable to those of distortion products in cochlear afferent responses. Responses to CF tones could be selectively suppressed by tones with frequency either higher or lower than CF; in most respects, mechanical two-tone suppression resembled rate suppression in cochlear afferents. Responses to clicks displayed a CF-specific compressive nonlinearity, similar to that present in responses to single tones, which could be profoundly and selectively reduced by furosemide. The present findings firmly support the hypothesis that all CF-specific nonlinearities present in the auditory nerve originate in analogous phenomena of basilar membrane vibration. However, because of their lability, it is almost certain that the mechanical nonlinearities themselves originate in outer hair cells.

Basilar Membrane Motion and Spike Initiation in the Cochlear Nerve

1986 ◽  
pp. 189-198 ◽  
Author(s):  
M. A. Ruggero ◽  
L. Robles ◽  
N. C. Rich ◽  
J. A. Costalupes
Keyword(s):  
Basilar Membrane ◽  
Cochlear Nerve ◽  
Spike Initiation

Two-tone suppression in the basilar membrane of the cochlea: mechanical basis of auditory-nerve rate suppression

1992 ◽  
Vol 68 (4) ◽  
pp. 1087-1099 ◽  
Author(s):  
M. A. Ruggero ◽  
L. Robles ◽  
N. C. Rich
Keyword(s):  
Auditory Nerve ◽  
Outer Hair Cell ◽  
Basilar Membrane ◽  
Frequency Tuning ◽  
Low Frequency ◽  
Nerve Fibers ◽  
Oval Window ◽  
Outer Hair Cells ◽  
Probe Intensity ◽  
Rate Suppression

1. The vibratory response to two-tone stimuli was measured in the basilar membrane of the chinchilla cochlea by means of the Mossbauer technique or laser velocimetry. Measurements were made at sites with characteristic frequency (CF, the frequency at which an auditory structure is most sensitive) of 7-10 kHz, located approximately 3.5 mm from the oval window. 2. Two-tone suppression (reduction in the response to one tone due to the presence of another) was demonstrated for CF probe tones and suppressor tones with frequencies both higher and lower than CF, at moderately low stimulus levels, including probe-suppressor combinations for which responses to the suppressor were lower than responses to the probe tone alone. 3. For a fixed suppressor tone, suppression magnitude decreased as a function of increasing probe intensity. 4. The magnitude of suppression increased monotonically with suppressor intensity. 5. The rate of growth of suppression magnitude with suppressor intensity was higher for suppressors in the region below CF than for those in the region above CF. 6. For low-frequency suppressor tones, suppression magnitude varied periodically, attaining one or two maxima within each period of the suppressor tone. 7. Suppression was frequency tuned: for either above-CF or below-CF suppressor tones, suppression magnitude reached a maximum for probe frequencies near CF. 8. Cochlear damage or death diminished or abolished suppression. There was a clear positive correlation between magnitude of suppression and basilar-membrane sensitivity for responses to CF tones. 9. Suppression tended to be accompanied by small phase lags in responses to CF probe tones. 10. Because all of the features of two-tone suppression at the basilar membrane match qualitatively (and, generally, also quantitatively) the features of two-tone rate suppression in auditory-nerve fibers, it is concluded that neural two-tone rate suppression originates in mechanical phenomena at the basilar membrane. 11. Because the lability of mechanical suppression parallels the loss of sensitivity and frequency tuning due to outer hair cell dysfunction, the present findings suggest that mechanical two-tone suppression arises from an interaction between the outer hair cells and the basilar membrane.

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.

scholarly journals Complementary metrics of human auditory nerve function derived from compound action potentials

2017 ◽  
Author(s):  
Kelly C. Harris ◽  
Kenneth I. Vaden ◽  
Carolyn M. McClaskey ◽  
James W. Dias ◽  
Judy R. Dubno
Keyword(s):  
Auditory Processing ◽  
Auditory Nerve ◽  
Noise Exposure ◽  
Basilar Membrane ◽  
Compound Action Potential ◽  
Neural Synchrony ◽  
Younger Adults ◽  
Physiological Properties ◽  
Compound Action Potentials ◽  
Compound Action

AbstractDeclines in auditory nerve (AN) function contribute to suprathreshold auditory processing and communication deficits in individuals with normal hearing, hearing loss, hyperacusis, and tinnitus. Procedures to characterize AN loss or dysfunction in humans are limited. We report several novel complementary metrics to characterize AN function noninvasively in humans using the compound action potential (CAP), a direct measure of summated AN activity. We examined how these metrics change with stimulus intensity, and interpreted these changes within a framework of known physiological properties of the basilar membrane and AN. Our results reveal how neural synchrony and the recruitment of AN fibers with later first-spike latencies likely contribute to the CAP, affect auditory processing, and differ with noise exposure history in younger adults despite normal pure-tone thresholds. Moving forward, these new metrics, when applied to patient populations, can provide a means to characterize cochlear synaptopathy and other deficits in AN function in humans.New and noteworthyLoss or inactivity of auditory nerve (AN) fibers is thought to contribute to suprathreshold auditory processing deficits, but evidence-based methods to assess these effects are not available. We describe several novel metrics that may be used to quantify neural synchrony and characterize AN function.

Sign in / Sign up

Export Citation Format

Share Document