Modeling the effects of medial olivocochlear efferent stimulation at the level of the inferior colliculus

Kwan, Timothy; Zilany, Muhammad S. A.; Davies-Venn, Evelyn E.; Wahab, Ahmad Khairi Abdul

doi:10.1007/s00221-019-05511-4

Cited by 3 publications

(2 citation statements)

References 32 publications

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“…2 C, albeit speculative, potentially adds further credibility to our hypothesis, in that these compensatory mechanisms may sometimes overshoot in their amount of compensation. Additionally, the MOC neurons also project rostrally to the inferior colliculus, a major site of generation for the 80 Hz ASSR and wave-V of the ABR, where they both increase and decrease the firing rate of different neuronal types as a function of input level 30 , 48 . The MOC neurons, therefore, have the potential to compensate for their self-imposed peripheral inhibition either through (1) the aforementioned cochlear nucleus feedback circuits, (2) directly influencing the inferior colliculus neurons, (3) a combination of influencing both the cochlear nucleus and inferior colliculus neurons, and/or (4) a different, currently unknown, pathway where the MOC projects.…”

Section: Discussionmentioning

confidence: 99%

Auditory brainstem mechanisms likely compensate for self-imposed peripheral inhibition

Boothalingam

Peterson

Powell

et al. 2023

Sci Rep

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Feedback networks in the brain regulate downstream auditory function as peripheral as the cochlea. However, the upstream neural consequences of this peripheral regulation are less understood. For instance, the medial olivocochlear reflex (MOCR) in the brainstem causes putative attenuation of responses generated in the cochlea and cortex, but those generated in the brainstem are perplexingly unaffected. Based on known neural circuitry, we hypothesized that the inhibition of peripheral input is compensated for by positive feedback in the brainstem over time. We predicted that the inhibition could be captured at the brainstem with shorter (1.5 s) than previously employed long duration (240 s) stimuli where this inhibition is likely compensated for. Results from 16 normal-hearing human listeners support our hypothesis in that when the MOCR is activated, there is a robust reduction of responses generated at the periphery, brainstem, and cortex for short-duration stimuli. Such inhibition at the brainstem, however, diminishes for long-duration stimuli suggesting some compensatory mechanisms at play. Our findings provide a novel non-invasive window into potential gain compensation mechanisms in the brainstem that may have implications for auditory disorders such as tinnitus. Our methodology will be useful in the evaluation of efferent function in individuals with hearing loss.

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Section: Discussionmentioning

confidence: 99%

Auditory brainstem mechanisms likely compensate for self-imposed peripheral inhibition

Boothalingam

Peterson

Powell

et al. 2023

Sci Rep

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“…Several previous AN models include efferent signals driven by the periphery (Clark et al, 2012; Giguere & Woodland, 1994; Kwan et al, 2019; Smalt et al, 2014; Yasin et al, 2020). In some of these previous implementations, cochlear gain was set to remain constant over time, omitting the dynamics of MOC efferents (Brown et al, 2010; Ferry & Meddis, 2007; Giguere & Woodland, 1994; Jennings et al, 2011).…”

Section: Discussionmentioning

confidence: 99%

Subcortical Auditory Model including Efferent Dynamic Gain Control with Inputs from Cochlear Nucleus and Inferior Colliculus

Farhadi

Jennings

Strickland

et al. 2022

Preprint

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The focus of most existing auditory models is on the afferent system. The auditory efferent system contains descending projections from several levels of the auditory pathway, from the auditory cortex to the brainstem, that control gain in the cochlea. We developed a model with a time-varying, gain-control signal from the efferent system that includes sub-cortical ascending and descending neural pathways. The medial olivocochlear (MOC) efferent stage of the model receives excitatory projections from both fluctuation-sensitive neurons in the inferior colliculus (IC) and wide-dynamic-range neurons in the cochlear nucleus (CN). The response of the model MOC stage controlled cochlear gain dynamically. Changes in the rates of IC neurons in awake rabbit to long-duration amplitude-modulated (AM) noise were employed to adjust the parameters of the proposed model. In response to AM stimuli, physiological response rates of most IC neurons with band-enhanced (BE) modulation transfer functions (MTFs) increased over a time course consistent with the dynamics of the MOC efferent feedback. The time constant of the MOC model that best matched the IC physiology was compared to available descriptions of the MOC. Responses of the proposed subcortical model to AM noise simulate the trend of increasing rate over time, while the model without the efferent system did not show this trend.

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Subcortical auditory model including efferent dynamic gain control with inputs from cochlear nucleus and inferior colliculus

Farhadi,

Jennings,

Strickland

et al. 2023

The Journal of the Acoustical Society of America

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An auditory model has been developed with a time-varying, gain-control signal based on the physiology of the efferent system and subcortical neural pathways. The medial olivocochlear (MOC) efferent stage of the model receives excitatory projections from fluctuation-sensitive model neurons of the inferior colliculus (IC) and wide-dynamic-range model neurons of the cochlear nucleus. The response of the model MOC stage dynamically controls cochlear gain via simulated outer hair cells. In response to amplitude-modulated (AM) noise, firing rates of most IC neurons with band-enhanced modulation transfer functions in awake rabbits increase over a time course consistent with the dynamics of the MOC efferent feedback. These changes in the rates of IC neurons in awake rabbits were employed to adjust the parameters of the efferent stage of the proposed model. Responses of the proposed model to AM noise were able to simulate the increasing IC rate over time, whereas the model without the efferent system did not show this trend. The proposed model with efferent gain control provides a powerful tool for testing hypotheses, shedding insight on mechanisms in hearing, specifically those involving the efferent system.

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Modeling the effects of medial olivocochlear efferent stimulation at the level of the inferior colliculus

Cited by 3 publications

References 32 publications

Auditory brainstem mechanisms likely compensate for self-imposed peripheral inhibition

Auditory brainstem mechanisms likely compensate for self-imposed peripheral inhibition

Subcortical Auditory Model including Efferent Dynamic Gain Control with Inputs from Cochlear Nucleus and Inferior Colliculus

Subcortical auditory model including efferent dynamic gain control with inputs from cochlear nucleus and inferior colliculus

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