Altered auditory feature discrimination in a rat model of Fragile X Syndrome.

Atypical sensory processing, particularly in the auditory domain, is one of the most common and quality-of-life affecting symptoms seen in autism spectrum disorders (ASD). Fragile X Syndrome (FXS) is a leading inherited cause of ASD and a majority of FXS individuals present with auditory processing...

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Main Authors: D Walker Gauthier, Noelle James, Benjamin D Auerbach
Format: Article
Language:English
Published: Public Library of Science (PLoS) 2025-07-01
Series:PLoS Biology
Online Access:https://doi.org/10.1371/journal.pbio.3003248
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author D Walker Gauthier
Noelle James
Benjamin D Auerbach
author_facet D Walker Gauthier
Noelle James
Benjamin D Auerbach
author_sort D Walker Gauthier
collection DOAJ
description Atypical sensory processing, particularly in the auditory domain, is one of the most common and quality-of-life affecting symptoms seen in autism spectrum disorders (ASD). Fragile X Syndrome (FXS) is a leading inherited cause of ASD and a majority of FXS individuals present with auditory processing alterations. While auditory hypersensitivity is a common phenotype observed in FXS and Fmr1 knockout (KO) rodent models, it is important to consider other auditory coding impairments that could contribute to sound processing difficulties and disrupted language comprehension in FXS. We have shown previously that a Fmr1 KO rat model of FXS exhibits heightened sound sensitivity that coincided with abnormal perceptual integration of stimulus bandwidth, indicative of altered spectral processing. Frequency discrimination is a fundamental aspect of sound encoding that is important for a range of auditory processes, such as source segregation and speech comprehension, and disrupted frequency coding could thus contribute to a range of auditory issues in FXS and ASD. Here we explicitly characterized spectral processing deficits in male Fmr1 KO rats using an operant conditioning tone discrimination assay and in vivo electrophysiological recordings from the auditory cortex and inferior colliculus. We found that Fmr1 KO rats exhibited poorer frequency resolution, which corresponded with neuronal hyperactivity and broader frequency tuning in auditory cortical but not collicular neurons. Using an experimentally informed population model, we show that these cortical physiological differences can recapitulate the observed behavior discrimination deficits, with decoder performance being tightly linked to differences in cortical tuning width and signal-to-noise ratios. Together, these findings indicate that cortical hyperexcitability in Fmr1 KO rats may act to preserve signal-to-noise ratios and signal detection threshold at the expense of sound sensitivity and fine feature discrimination, highlighting a potential mechanistic locus for a range of auditory behavioral phenotypes in FXS.
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spelling doaj-art-5ced3146a87d4188866b0f94884c1a132025-08-20T03:29:14ZengPublic Library of Science (PLoS)PLoS Biology1544-91731545-78852025-07-01237e300324810.1371/journal.pbio.3003248Altered auditory feature discrimination in a rat model of Fragile X Syndrome.D Walker GauthierNoelle JamesBenjamin D AuerbachAtypical sensory processing, particularly in the auditory domain, is one of the most common and quality-of-life affecting symptoms seen in autism spectrum disorders (ASD). Fragile X Syndrome (FXS) is a leading inherited cause of ASD and a majority of FXS individuals present with auditory processing alterations. While auditory hypersensitivity is a common phenotype observed in FXS and Fmr1 knockout (KO) rodent models, it is important to consider other auditory coding impairments that could contribute to sound processing difficulties and disrupted language comprehension in FXS. We have shown previously that a Fmr1 KO rat model of FXS exhibits heightened sound sensitivity that coincided with abnormal perceptual integration of stimulus bandwidth, indicative of altered spectral processing. Frequency discrimination is a fundamental aspect of sound encoding that is important for a range of auditory processes, such as source segregation and speech comprehension, and disrupted frequency coding could thus contribute to a range of auditory issues in FXS and ASD. Here we explicitly characterized spectral processing deficits in male Fmr1 KO rats using an operant conditioning tone discrimination assay and in vivo electrophysiological recordings from the auditory cortex and inferior colliculus. We found that Fmr1 KO rats exhibited poorer frequency resolution, which corresponded with neuronal hyperactivity and broader frequency tuning in auditory cortical but not collicular neurons. Using an experimentally informed population model, we show that these cortical physiological differences can recapitulate the observed behavior discrimination deficits, with decoder performance being tightly linked to differences in cortical tuning width and signal-to-noise ratios. Together, these findings indicate that cortical hyperexcitability in Fmr1 KO rats may act to preserve signal-to-noise ratios and signal detection threshold at the expense of sound sensitivity and fine feature discrimination, highlighting a potential mechanistic locus for a range of auditory behavioral phenotypes in FXS.https://doi.org/10.1371/journal.pbio.3003248
spellingShingle D Walker Gauthier
Noelle James
Benjamin D Auerbach
Altered auditory feature discrimination in a rat model of Fragile X Syndrome.
PLoS Biology
title Altered auditory feature discrimination in a rat model of Fragile X Syndrome.
title_full Altered auditory feature discrimination in a rat model of Fragile X Syndrome.
title_fullStr Altered auditory feature discrimination in a rat model of Fragile X Syndrome.
title_full_unstemmed Altered auditory feature discrimination in a rat model of Fragile X Syndrome.
title_short Altered auditory feature discrimination in a rat model of Fragile X Syndrome.
title_sort altered auditory feature discrimination in a rat model of fragile x syndrome
url https://doi.org/10.1371/journal.pbio.3003248
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AT noellejames alteredauditoryfeaturediscriminationinaratmodeloffragilexsyndrome
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