Publication Date
9-1-2024
Document Type
Article
Publication Title
eNeuro
Volume
11
Issue
9
DOI
10.1523/ENEURO.0365-24.2024
Abstract
Previous physiological and psychophysical studies have explored whether feedback to the cochlea from the efferent system influences forward masking. The present work proposes that the limited growth-of-masking (GOM) observed in auditory nerve (AN) fibers may have been misunderstood; namely, that this limitation may be due to the influence of anesthesia on the efferent system. Building on the premise that the unanesthetized AN may exhibit GOM similar to more central nuclei, the present computational modeling study demonstrates that feedback from the medial olivocochlear (MOC) efferents may contribute to GOM observed physiologically in onset-type neurons in both the cochlear nucleus and inferior colliculus (IC). Additionally, the computational model of MOC efferents used here generates a decrease in masking with longer masker-signal delays similar to that observed in IC physiology and in psychophysical studies. An advantage of this explanation over alternative physiological explanations (e.g., that forward masking requires inhibition from the superior paraolivary nucleus) is that this theory can explain forward masking observed in the brainstem, early in the ascending pathway. For explaining psychoacoustic results, one strength of this model is that it can account for the lack of elevation in thresholds observed when masker level is randomly varied from interval-to-interval, a result that is difficult to explain using the conventional temporal window model of psychophysical forward masking. Future directions for evaluating the efferent mechanism as a contributing mechanism for psychoacoustic results are discussed.
Funding Number
RFP2022
Funding Sponsor
Hearing Industry Research Consortium
Keywords
auditory nerve, computational model, forward masking, inferior colliculus, medial olivocochlear reflex, temporal window
Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 License.
Department
Audiology
Recommended Citation
Braden N. Maxwell, Afagh Farhadi, Marc A. Brennan, Adam Svec, and Laurel H. Carney. "A Subcortical Model for Auditory Forward Masking with Efferent Control of Cochlear Gain" eNeuro (2024). https://doi.org/10.1523/ENEURO.0365-24.2024
