No Change in Medial Olivocochlear Efferent Activity during an Auditory or Visual Task: Dual Evidence from Otoacoustic Emissions and Event-Related Potentials.

W Wiktor Jedrzejczak,Rafal Milner,Henryk Skarzynski,Malgorzata Ganc,Edyta Pilka

doi:10.3390/brainsci10110894

W Wiktor Jedrzejczak, Rafal Milner + Show 3 more

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https://doi.org/10.3390/brainsci10110894

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Abstract

The medial olivocochlear (MOC) system is thought to be responsible for modulation of peripheral hearing through descending (efferent) pathways. This study investigated the connection between peripheral hearing function and conscious attention during two different modality tasks, auditory and visual. Peripheral hearing function was evaluated by analyzing the amount of suppression of otoacoustic emissions (OAEs) by contralateral acoustic stimulation (CAS), a well-known effect of the MOC. Simultaneously, attention was evaluated by event-related potentials (ERPs). Although the ERPs showed clear differences in processing of auditory and visual tasks, there were no differences in the levels of OAE suppression. We also analyzed OAEs for the highest magnitude resonant mode signal detected by the matching pursuit method, but again did not find a significant effect of task, and no difference in noise level or number of rejected trials. However, for auditory tasks, the amplitude of the P3 cognitive wave negatively correlated with the level of OAE suppression. We conclude that there seems to be no change in MOC function when performing different modality tasks, although the cortex still remains able to modulate some aspects of MOC activity.

Highlights

Everyone with normal hearing sometimes experiences, when focusing on visual information, failure to hear surrounding sounds, for example, while reading we ignore background sounds and may not even hear someone talking to us
There was no significant difference between transiently evoked OAEs (TEOAEs) suppression measured during auditory and visual tasks (for dB effect, t(38) = −0.19, p = 0.84 and for percentage effect, t(38) =
This study has investigated whether changing attention from the auditory to the visual modality has an effect on the medial olivocochlear (MOC) system

Summary

Introduction

Everyone with normal hearing sometimes experiences, when focusing on visual information, failure to hear surrounding sounds, for example, while reading we ignore background sounds and may not even hear someone talking to us. If we focus our attention on auditory information, such as listening to a radio or another person, it is difficult to read. If the ear itself plays an active or “conscious” part in switching attention, it is most likely to be through activity of the medial olivocochlear (MOC) system. MOC neurons descend from the brainstem to the cochleae of both ears, while the brainstem receives input from auditory cortex. The function of this system is not entirely understood; probably its role relates to bilateral hearing tasks such as localization or detecting speech in noise [1,2]. The activity of this system can be studied noninvasively by measuring changes in otoacoustic emissions (OAEs) in response to

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