scholarly journals Medial-olivocochlear-efferent inhibition of the first peak of auditory-nerve responses: Evidence for a new motion within the cochlea

2005 ◽  
Vol 118 (4) ◽  
pp. 2421-2433 ◽  
Author(s):  
John J. Guinan ◽  
Tai Lin ◽  
Holden Cheng
Keyword(s):  
Auditory Nerve ◽  
Efferent Inhibition ◽  
Medial Olivocochlear

scholarly journals The role of efferents in human auditory development: efferent inhibition predicts frequency discrimination in noise for children

2020 ◽  
Vol 123 (6) ◽  
pp. 2437-2448 ◽  
Author(s):  
Srikanta K. Mishra
Keyword(s):  
Frequency Discrimination ◽  
Childhood Development ◽  
Older Children ◽  
Efferent System ◽  
Efferent Inhibition ◽  
Hearing In Noise ◽  
Medial Olivocochlear Efferents ◽  
Medial Olivocochlear ◽  
Listening In Noise

Despite several decades of research, the functional role of medial olivocochlear efferents in humans remains controversial and is thought to be insignificant. Here it is shown that medial efferent inhibition strongly predicts frequency discrimination in noise for younger children but not for older children and adults. Young children are relatively more dependent on the efferent system for listening-in-noise. This study highlights the role of the efferent system in hearing-in-noise during childhood development.

The Influence of Efferent Inhibition on Speech Perception in Noise: A Revisit Through Its Level-Dependent Function

2019 ◽  
Vol 28 (2S) ◽  
pp. 508-515
Author(s):  
L. Yashaswini ◽  
Sandeep Maruthy
Keyword(s):  
Speech Perception ◽  
Broadband Noise ◽  
Speech Perception In Noise ◽  
Contralateral Noise ◽  
Olivocochlear Bundle ◽  
Efferent Inhibition ◽  
Dependent Function ◽  
Contralateral Suppression ◽  
Medial Olivocochlear ◽  
Medial Olivocochlear Bundle

Purpose The study aimed to assess the relationship between the level-dependent function of efferent inhibition and speech perception in noise across different intensities of suppressor and across different signal-to-noise ratios (SNRs) of speech. Method Twenty-six young normal-hearing adults participated in the study. Contralateral suppression of transient evoked otoacoustic emissions (TEOAEs) was measured for 3 levels of suppressor (40, 50, and 60 dB SPL). Speech identification score (SIS) was measured at 5 ipsilateral SNR conditions (quiet, 0, −5, −10, and −15 dB), with and without contralateral broadband noise at 3 levels (40, 50, and 60 dB SPL). Furthermore, SNR-50 was measured with and without the same 3 levels of contralateral broadband noise. Results The results showed that the suppression magnitude of TEOAE increased with an increase in suppressor level. However, neither SIS nor SNR-50 was influenced by the contralateral noise. In addition, SIS and SNR-50 did not show significant correlation with contralateral suppression of TEOAEs. This was true at all the SNRs and contralateral noise levels used in the study. Conclusions The findings suggest that the intensity of noise directly influences medial olivocochlear bundle–mediated efferent inhibition. However, the role of the medial olivocochlear bundle in regulating speech perception in noise needs to be revisited. Supplemental Material https://doi.org/10.23641/asha.9336353

scholarly journals Recording and labeling at a site along the cochlea shows alignment of medial olivocochlear and auditory nerve tonotopic mappings

2016 ◽  
Vol 115 (3) ◽  
pp. 1644-1653 ◽  
Author(s):  
M. Christian Brown
Keyword(s):  
Hair Cells ◽  
Auditory Nerve ◽  
Extracellular Recording ◽  
Nerve Fibers ◽  
Outer Hair Cells ◽  
Basal Turn ◽  
Afferent Fibers ◽  
Medial Olivocochlear ◽  
A Site

Medial olivocochlear (MOC) neurons provide an efferent innervation to outer hair cells (OHCs) of the cochlea, but their tonotopic mapping is incompletely known. In the present study of anesthetized guinea pigs, the MOC mapping was investigated using in vivo, extracellular recording, and labeling at a site along the cochlear course of the axons. The MOC axons enter the cochlea at its base and spiral apically, successively turning out to innervate OHCs according to their characteristic frequencies (CFs). Recordings made at a site in the cochlear basal turn yielded a distribution of MOC CFs with an upper limit, or “edge,” due to usually absent higher-CF axons that presumably innervate more basal locations. The CFs at the edge, normalized across preparations, were equal to the CFs of the auditory nerve fibers (ANFs) at the recording sites (near 16 kHz). Corresponding anatomical data from extracellular injections showed spiraling MOC axons giving rise to an edge of labeling at the position of a narrow band of labeled ANFs. Overall, the edges of the MOC CFs and labeling, with their correspondences to ANFs, suggest similar tonotopic mappings of these efferent and afferent fibers, at least in the cochlear basal turn. They also suggest that MOC axons miss much of the position of the more basally located cochlear amplifier appropriate for their CF; instead, the MOC innervation may be optimized for protection from damage by acoustic overstimulation.

Sign in / Sign up

Export Citation Format

Share Document