scholarly journals Electrocochleography in Auditory Neuropathy Related to Mutations in the OTOF or OPA1 Gene

2021 ◽  
Vol 11 (4) ◽  
pp. 639-652
Author(s):  
Rosamaria Santarelli ◽  
Pietro Scimemi ◽  
Chiara La Morgia ◽  
Elona Cama ◽  
Ignacio del Castillo ◽  
...  
Keyword(s):  
Hair Cell ◽  
Auditory Nerve ◽  
Nerve Fibers ◽  
Temporal Coding ◽  
Auditory Neuropathy ◽  
Auditory Brainstem Responses ◽  
Inner Hair Cell ◽  
Ribbon Synapses ◽  
Summating Potential ◽  
Auditory Nerve Fibers

Auditory Neuropathy (AN) is a hearing disorder characterized by disruption of temporal coding of acoustic signals in auditory nerve fibers resulting in the impairment of auditory perceptions that rely on temporal cues. Mutations in several nuclear and mitochondrial genes have been associated to the most well-known forms of AN. Underlying mechanisms include both pre-synaptic and post-synaptic disorders affecting inner hair cell (IHC) depolarization, neurotransmitter release from ribbon synapses, spike initiation in auditory nerve terminals, loss of nerve fibers and impaired conduction, all occurring in the presence of normal physiological measures of outer hair cell (OHC) activities (otoacoustic emissions [OAEs] and cochlear microphonic [CM]). Disordered synchrony of auditory nerve activity has been suggested as the basis of both the profound alterations of auditory brainstem responses (ABRs) and impairment of speech perception. We will review how electrocochleography (ECochG) recordings provide detailed information to help objectively define the sites of auditory neural dysfunction and their effect on inner hair cell receptor summating potential (SP) and compound action potential (CAP), the latter reflecting disorders of ribbon synapses and auditory nerve fibers.

Spontaneous Activity of Auditory Nerve Fibers in the Barn Owl (Tyto alba): Analyses of Interspike Interval Distributions

2009 ◽  
Vol 101 (6) ◽  
pp. 3169-3191 ◽  
Author(s):  
Heinrich Neubauer ◽  
Christine Köppl ◽  
Peter Heil
Keyword(s):  
Spontaneous Activity ◽  
Auditory Nerve ◽  
Interspike Interval ◽  
Barn Owl ◽  
Nerve Fibers ◽  
Temporal Coding ◽  
Tyto Alba ◽  
Ribbon Synapses ◽  
Auditory Systems ◽  
The Mean

In vertebrate auditory systems, the conversion from graded receptor potentials across the hair-cell membrane into stochastic spike trains of the auditory nerve (AN) fibers is performed by ribbon synapses. The statistics underlying this process constrain auditory coding but are not precisely known. Here, we examine the distributions of interspike intervals (ISIs) from spontaneous activity of AN fibers of the barn owl ( Tyto alba), a nocturnal avian predator whose auditory system is specialized for precise temporal coding. The spontaneous activity of AN fibers, with the exception of those showing preferred intervals, is commonly thought to result from excitatory events generated by a homogeneous Poisson point process, which lead to spikes unless the fiber is refractory. We show that the ISI distributions in the owl are better explained as resulting from the action of a brief refractory period (∼0.5 ms) on excitatory events generated by a homogeneous stochastic process where the distribution of interevent intervals is a mixture of an exponential and a gamma distribution with shape factor 2, both with the same scaling parameter. The same model was previously shown to apply to AN fibers in the cat. However, the mean proportions of exponentially versus gamma-distributed intervals in the mixture were different for cat and owl. Furthermore, those proportions were constant across fibers in the cat, whereas they covaried with mean spontaneous rate and with characteristic frequency in the owl. We hypothesize that in birds, unlike in mammals, more than one ribbon may provide excitation to most fibers, accounting for the different proportions, and that variation in the number of ribbons may underlie the variation in the proportions.

scholarly journals Temporal Coding of Periodicity Pitch in the Auditory System: An Overview

1999 ◽  
Vol 6 (4) ◽  
pp. 147-172 ◽  
Author(s):  
Peter Cariani
Keyword(s):  
Cochlear Nucleus ◽  
Auditory Nerve ◽  
Sensory Information ◽  
Nerve Fibers ◽  
Temporal Coding ◽  
Single Type ◽  
Time Of Arrival ◽  
Type I ◽  
Pitch Frequency ◽  
Auditory Nerve Fibers

This paper outlines a taxonomy of neural pulse codes and reviews neurophysiological evidence for interspike interval-based representations for pitch and timbre in the auditory nerve and cochlear nucleus. Neural pulse codes can be divided into channel-based codes, temporal-pattern codes, and time-of-arrival codes. Timings of discharges in auditory nerve fibers reflect the time structure of acoustic waveforms, such that the interspike intervals that are produced precisely convey information concerning stimulus periodicities. Population-wide inter-spike interval distributions are constructed by summing together intervals from the observed responses of many single Type I auditory nerve fibers. Features in such distributions correspond closely with pitches that are heard by human listeners. The most common all-order interval present in the auditory nerve array almost invariably corresponds to the pitch frequency, whereas the relative fraction of pitchrelated intervals amongst all others qualitatively corresponds to the strength of the pitch. Consequently, many diverse aspects of pitch perception are explained in terms of such temporal representations. Similar stimulus-driven temporal discharge patterns are observed in major neuronal populations of the cochlear nucleus. Population-interval distributions constitute an alternative time-domain strategy for representing sensory information that complements spatially organized sensory maps. Similar autocorrelation-like representations are possible in other sensory systems, in which neural discharges are time-locked to stimulus waveforms.

scholarly journals Refractoriness Enhances Temporal Coding by Auditory Nerve Fibers

2013 ◽  
Vol 33 (18) ◽  
pp. 7681-7690 ◽  
Author(s):  
M. Avissar ◽  
J. H. Wittig ◽  
J. C. Saunders ◽  
T. D. Parsons
Keyword(s):  
Auditory Nerve ◽  
Nerve Fibers ◽  
Temporal Coding ◽  
Auditory Nerve Fibers

scholarly journals Mechanics of the Mammalian Cochlea

2001 ◽  
Vol 81 (3) ◽  
pp. 1305-1352 ◽  
Author(s):  
Luis Robles ◽  
Mario A. Ruggero
Keyword(s):  
Hair Cell ◽  
Auditory Nerve ◽  
Basilar Membrane ◽  
Frequency Tuning ◽  
Stimulus Frequency ◽  
Nerve Fibers ◽  
Outer Hair Cells ◽  
Cochlear Amplifier ◽  
Ear Ossicles ◽  
Auditory Nerve Fibers

In mammals, environmental sounds stimulate the auditory receptor, the cochlea, via vibrations of the stapes, the innermost of the middle ear ossicles. These vibrations produce displacement waves that travel on the elongated and spirally wound basilar membrane (BM). As they travel, waves grow in amplitude, reaching a maximum and then dying out. The location of maximum BM motion is a function of stimulus frequency, with high-frequency waves being localized to the “base” of the cochlea (near the stapes) and low-frequency waves approaching the “apex” of the cochlea. Thus each cochlear site has a characteristic frequency (CF), to which it responds maximally. BM vibrations produce motion of hair cell stereocilia, which gates stereociliar transduction channels leading to the generation of hair cell receptor potentials and the excitation of afferent auditory nerve fibers. At the base of the cochlea, BM motion exhibits a CF-specific and level-dependent compressive nonlinearity such that responses to low-level, near-CF stimuli are sensitive and sharply frequency-tuned and responses to intense stimuli are insensitive and poorly tuned. The high sensitivity and sharp-frequency tuning, as well as compression and other nonlinearities (two-tone suppression and intermodulation distortion), are highly labile, indicating the presence in normal cochleae of a positive feedback from the organ of Corti, the “cochlear amplifier.” This mechanism involves forces generated by the outer hair cells and controlled, directly or indirectly, by their transduction currents. At the apex of the cochlea, nonlinearities appear to be less prominent than at the base, perhaps implying that the cochlear amplifier plays a lesser role in determining apical mechanical responses to sound. Whether at the base or the apex, the properties of BM vibration adequately account for most frequency-specific properties of the responses to sound of auditory nerve fibers.

scholarly journals Temporal Coding of Single Auditory Nerve Fibers Is Not Degraded in Aging Gerbils

2019 ◽  
Vol 40 (2) ◽  
pp. 343-354 ◽  
Author(s):  
Amarins N. Heeringa ◽  
Lichun Zhang ◽  
Go Ashida ◽  
Rainer Beutelmann ◽  
Friederike Steenken ◽  
...  
Keyword(s):  
Auditory Nerve ◽  
Nerve Fibers ◽  
Temporal Coding ◽  
Auditory Nerve Fibers
Sign in / Sign up

Export Citation Format

Share Document