Cochlear microphonics and the initiation of spikes in the auditory nerve: Correlation of single‐unit data with neural and receptor potentials recorded from the round window

1986 ◽  
Vol 79 (5) ◽  
pp. 1491-1498 ◽  
Author(s):  
Mario A. Ruggero ◽  
Luis Robles ◽  
Nola C. Rich
Keyword(s):  
Auditory Nerve ◽  
Single Unit ◽  
Round Window ◽  
Cochlear Microphonics

Contribution of auditory nerve fibers to compound action potential of the auditory nerve

2014 ◽  
Vol 112 (5) ◽  
pp. 1025-1039 ◽  
Author(s):  
Jérôme Bourien ◽  
Yong Tang ◽  
Charlène Batrel ◽  
Antoine Huet ◽  
Marc Lenoir ◽  
...  
Keyword(s):  
Action Potential ◽  
Auditory Nerve ◽  
Computational Simulation ◽  
Round Window ◽  
Hearing Threshold ◽  
Compound Action Potential ◽  
Nerve Fibers ◽  
Auditory Nerve Fibers ◽  
Round Window Niche ◽  
Compound Action

Sound-evoked compound action potential (CAP), which captures the synchronous activation of the auditory nerve fibers (ANFs), is commonly used to probe deafness in experimental and clinical settings. All ANFs are believed to contribute to CAP threshold and amplitude: low sound pressure levels activate the high-spontaneous rate (SR) fibers, and increasing levels gradually recruit medium- and then low-SR fibers. In this study, we quantitatively analyze the contribution of the ANFs to CAP 6 days after 30-min infusion of ouabain into the round window niche. Anatomic examination showed a progressive ablation of ANFs following increasing concentration of ouabain. CAP amplitude and threshold plotted against loss of ANFs revealed three ANF pools: 1) a highly ouabain-sensitive pool, which does not participate in either CAP threshold or amplitude, 2) a less sensitive pool, which only encoded CAP amplitude, and 3) a ouabain-resistant pool, required for CAP threshold and amplitude. Remarkably, distribution of the three pools was similar to the SR-based ANF distribution (low-, medium-, and high-SR fibers), suggesting that the low-SR fiber loss leaves the CAP unaffected. Single-unit recordings from the auditory nerve confirmed this hypothesis and further showed that it is due to the delayed and broad first spike latency distribution of low-SR fibers. In addition to unraveling the neural mechanisms that encode CAP, our computational simulation of an assembly of guinea pig ANFs generalizes and extends our experimental findings to different species of mammals. Altogether, our data demonstrate that substantial ANF loss can coexist with normal hearing threshold and even unchanged CAP amplitude.

Electrical Cochlear Stimulation in the Deaf Cat: Comparisons Between Psychophysical and Central Auditory Neuronal Thresholds

2000 ◽  
Vol 83 (4) ◽  
pp. 2145-2162 ◽  
Author(s):  
Ralph E. Beitel ◽  
Russell L. Snyder ◽  
Christoph E. Schreiner ◽  
Marcia W. Raggio ◽  
Patricia A. Leake
Keyword(s):  
Electrical Stimulation ◽  
Auditory System ◽  
Pulse Rate ◽  
Auditory Nerve ◽  
Round Window ◽  
Electrode Array ◽  
Scala Tympani ◽  
Behavioral Thresholds ◽  
Current Pulses ◽  
Stimulation Of

Cochlear prostheses for electrical stimulation of the auditory nerve (“electrical hearing”) can provide auditory capacity for profoundly deaf adults and children, including in many cases a restored ability to perceive speech without visual cues. A fundamental challenge in auditory neuroscience is to understand the neural and perceptual mechanisms that make rehabilitation of hearing possible in these deaf humans. We have developed a feline behavioral model that allows us to study behavioral and physiological variables in the same deaf animals. Cats deafened by injection of ototoxic antibiotics were implanted with either a monopolar round window electrode or a multichannel scala tympani electrode array. To evaluate the effects of perceptually significant electrical stimulation of the auditory nerve on the central auditory system, an animal was trained to avoid a mild electrocutaneous shock when biphasic current pulses (0.2 ms/phase) were delivered to its implanted cochlea. Psychophysical detection thresholds and electrical auditory brain stem response (EABR) thresholds were estimated in each cat. At the conclusion of behavioral testing, acute physiological experiments were conducted, and threshold responses were recorded for single neurons and multineuronal clusters in the central nucleus of the inferior colliculus (ICC) and the primary auditory cortex (A1). Behavioral and neurophysiological thresholds were evaluated with reference to cochlear histopathology in the same deaf cats. The results of the present study include: 1) in the cats implanted with a scala tympani electrode array, the lowest ICC and A1 neural thresholds were virtually identical to the behavioral thresholds for intracochlear bipolar stimulation; 2) behavioral thresholds were lower than ICC and A1 neural thresholds in each of the cats implanted with a monopolar round window electrode; 3) EABR thresholds were higher than behavioral thresholds in all of the cats (mean difference = 6.5 dB); and 4) the cumulative number of action potentials for a sample of ICC neurons increased monotonically as a function of the amplitude and the number of stimulating biphasic pulses. This physiological result suggests that the output from the ICC may be integrated spatially across neurons and temporally integrated across pulses when the auditory nerve array is stimulated with a train of biphasic current pulses. Because behavioral thresholds were lower and reaction times were faster at a pulse rate of 30 pps compared with a pulse rate of 2 pps, spatial-temporal integration in the central auditory system was presumably reflected in psychophysical performance.

scholarly journals PromBERA: A preoperative eABR: An update

2018 ◽  
Vol 4 (1) ◽  
pp. 563-565 ◽  
Author(s):  
Daniel Polterauer ◽  
Maike Neuling ◽  
Joachim Müller ◽  
John-Martin Hempel ◽  
Giacomo Mandruzzato ◽  
...  
Keyword(s):  
Cochlear Implantation ◽  
Auditory Nerve ◽  
Round Window ◽  
Electrode Array ◽  
Auditory Brainstem ◽  
Auditory Brainstem Responses ◽  
Speech Comprehension ◽  
Testing Procedures ◽  
Brainstem Response ◽  
Round Window Niche

AbstractPrior to cochlear implantation, audiological tests are performed to determine candidacy in subjects with a hearing loss. This is usually done by measuring the acoustic auditory brainstem response (ABR). Unfortunately, for some subjects, a reproducible ABR recording cannot be obtained, even at high acoustic levels. Having a healthy stimulating auditory nerve is required for cochlear implantation in order to benefit from the electrical pulses that are generated by the implant and to improve speech comprehension. In some subjects, this prerequisite cannot be measured using routine audiological tests. In this study, the feasibility of recording electrically evoked auditory brainstem responses (eABR) using a stimulating transtympanic electrode, placed on the round window niche, together with MED-EL clinical system is investigated. The results show that it is possible to record reproducible eABR measurements using PromBERA. The response was also confirmed with intraoperative eABR measurements that were stimulated using the implanted CI electrode array. Similarities between the intraoperative measurements and the preoperative recorded waveforms were observed. In summary, the integrity and excitability of the auditory nerve can be objectively measured using the PromBERA in subjects where standard clinical testing procedures are unable to provide the information required.

scholarly journals BDNF Increases Survival and Neuronal Differentiation of Human Neural Precursor Cells Cotransplanted with a Nanofiber Gel to the Auditory Nerve in a Rat Model of Neuronal Damage

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Yu Jiao ◽  
Björn Palmgren ◽  
Ekaterina Novozhilova ◽  
Ulrica Englund Johansson ◽  
Anne L. Spieles-Engemann ◽  
...  
Keyword(s):  
Neuronal Differentiation ◽  
Auditory Nerve ◽  
Neuronal Damage ◽  
Round Window ◽  
Precursor Cells ◽  
Neural Precursor Cells ◽  
Neural Precursor ◽  
Phenotypic Differentiation ◽  
Round Window Niche ◽  
The Brain

Objectives. To study possible nerve regeneration of a damaged auditory nerve by the use of stem cell transplantation.Methods. We transplanted HNPCs to the rat AN trunk by the internal auditory meatus (IAM). Furthermore, we studied if addition of BDNF affects survival and phenotypic differentiation of the grafted HNPCs. A bioactive nanofiber gel (PA gel), in selected groups mixed with BDNF, was applied close to the implanted cells. Before transplantation, all rats had been deafened by a round window niche application ofβ-bungarotoxin. This neurotoxin causes a selective toxic destruction of the AN while keeping the hair cells intact.Results. Overall, HNPCs survived well for up to six weeks in all groups. However, transplants receiving the BDNF-containing PA gel demonstrated significantly higher numbers of HNPCs and neuronal differentiation. At six weeks, a majority of the HNPCs had migrated into the brain stem and differentiated. Differentiated human cells as well as neurites were observed in the vicinity of the cochlear nucleus.Conclusion. Our results indicate that human neural precursor cells (HNPC) integration with host tissue benefits from additional brain derived neurotrophic factor (BDNF) treatment and that these cells appear to be good candidates for further regenerative studies on the auditory nerve (AN).

scholarly journals Cochlear NMDA Receptors as a Therapeutic Target of Noise-Induced Tinnitus

2015 ◽  
Vol 35 (5) ◽  
pp. 1905-1923 ◽  
Author(s):  
Dan Bing ◽  
Sze Chim Lee ◽  
Dario Campanelli ◽  
Hao Xiong ◽  
Masahiro Matsumoto ◽  
...  
Keyword(s):  
Nmda Receptor ◽  
Auditory Nerve ◽  
Noise Exposure ◽  
Round Window ◽  
Receptor Activation ◽  
Auditory Brainstem ◽  
Nmda Receptor Antagonist ◽  
Inner Hair Cell ◽  
Ribbon Synapses ◽  
Brainstem Response

Background: Accumulating evidence suggests that tinnitus may occur despite normal auditory sensitivity, probably linked to partial degeneration of the cochlear nerve and damage of the inner hair cell (IHC) synapse. Damage to the IHC synapses and deafferentation may occur even after moderate noise exposure. For both salicylate- and noise-induced tinnitus, aberrant N-methyl-d-aspartate (NMDA) receptor activation and related auditory nerve excitation have been suggested as origin of cochlear tinnitus. Accordingly, NMDA receptor inhibition has been proposed as a pharmacologic approach for treatment of synaptopathic tinnitus. Methods: Round-window application of the NMDA receptor antagonist AM-101 (Esketamine hydrochloride gel; Auris Medical AG, Basel, Switzerland) was tested in an animal model of tinnitus induced by acute traumatic noise. The study included the quantification of IHC ribbon synapses as a correlate for deafferentation as well as the measurement of the auditory brainstem response (ABR) to close-threshold sensation level stimuli as an indication of sound-induced auditory nerve activity. Results: We have shown that AM-101 reduced the trauma-induced loss of IHC ribbons and counteracted the decline of ABR wave I amplitude generated in the cochlea/auditory nerve. Conclusion: Local round-window application of AM-101 may be a promising therapeutic intervention for the treatment of synaptopathic tinnitus.

scholarly journals Effects of Calcitonin-Gene-Related-Peptide on Auditory Nerve Activity

2021 ◽  
Vol 9 ◽  
Author(s):  
Colleen G. Le Prell ◽  
Larry F. Hughes ◽  
David F. Dolan ◽  
Sanford C. Bledsoe
Keyword(s):  
Auditory Nerve ◽  
Outer Hair Cell ◽  
Round Window ◽  
Calcitonin Gene Related Peptide ◽  
Distortion Product Otoacoustic Emission ◽  
Nerve Activity ◽  
Distortion Product ◽  
Related Peptide ◽  
Calcitonin Gene ◽  
Brainstem Response

Calcitonin-gene-related peptide (CGRP) is a lateral olivocochlear (LOC) efferent neurotransmitter. Depression of sound-driven auditory brainstem response amplitude in CGRP-null mice suggests the potential for endogenous CGRP release to upregulate spontaneous and/or sound-driven auditory nerve (AN) activity. We chronically infused CGRP into the guinea pig cochlea and evaluated changes in AN activity as well as outer hair cell (OHC) function. The amplitude of both round window noise (a measure of ensemble spontaneous activity) and the synchronous whole-nerve response to sound (compound action potential, CAP) were enhanced. Lack of change in both onset adaptation and steady state amplitude of sound-evoked distortion product otoacoustic emission (DPOAE) responses indicated CGRP had no effect on OHCs, suggesting the origin of the observed changes was neural. Combined with results from the CGRP-null mice, these results appear to confirm that endogenous CGRP enhances auditory nerve activity when released by the LOC neurons. However, infusion of the CGRP receptor antagonist CGRP (8–37) did not reliably influence spontaneous or sound-driven AN activity, or OHC function, results that contrast with the decreased ABR amplitude measured in CGRP-null mice.

Brain Stem Response Evoked by Electrical Stimulation of the round Window of the Guinea Pig

1981 ◽  
Vol 89 (1) ◽  
pp. 117-124 ◽  
Author(s):  
Hitoshi Yamane ◽  
Roger R. Marsh ◽  
William P. Potsic
Keyword(s):  
Electrical Stimulation ◽  
Guinea Pig ◽  
Auditory Nerve ◽  
Round Window ◽  
Direct Electrical Stimulation ◽  
Output Function ◽  
Input Output ◽  
Nerve Excitability ◽  
Brain Stem Response ◽  
Stimulation Of

The wave that is believed to correspond to wave V in man is an appropriate indicator of auditory nerve excitability because it is not contaminated by nonauditory neurogenic responses to electrical stimulation. The responses to direct electrical stimulation of the auditory nerve could be distinguished from the electrophonic response by the steep input-output function and constant latency of the former. Myogenic responses are prominent unless a muscle relaxant is administered.

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