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Long-Term Evolution of Brainstem Electrical Evoked Responses to Sound after Restricted Ablation of the Auditory Cortex

INTRODUCTION: This study aimed to assess the top-down control of sound processing in the auditory brainstem of rats. Short latency evoked responses were analyzed after unilateral or bilateral ablation of auditory cortex. This experimental paradigm was also used towards analyzing the long-term evolut...

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Autores principales: Lamas, Verónica, Alvarado, Juan C., Carro, Juan, Merchán, Miguel A.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Public Library of Science 2013
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3774800/
https://www.ncbi.nlm.nih.gov/pubmed/24066057
http://dx.doi.org/10.1371/journal.pone.0073585
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author Lamas, Verónica
Alvarado, Juan C.
Carro, Juan
Merchán, Miguel A.
author_facet Lamas, Verónica
Alvarado, Juan C.
Carro, Juan
Merchán, Miguel A.
author_sort Lamas, Verónica
collection PubMed
description INTRODUCTION: This study aimed to assess the top-down control of sound processing in the auditory brainstem of rats. Short latency evoked responses were analyzed after unilateral or bilateral ablation of auditory cortex. This experimental paradigm was also used towards analyzing the long-term evolution of post-lesion plasticity in the auditory system and its ability to self-repair. METHOD: Auditory cortex lesions were performed in rats by stereotactically guided fine-needle aspiration of the cerebrocortical surface. Auditory Brainstem Responses (ABR) were recorded at post-surgery day (PSD) 1, 7, 15 and 30. Recordings were performed under closed-field conditions, using click trains at different sound intensity levels, followed by statistical analysis of threshold values and ABR amplitude and latency variables. Subsequently, brains were sectioned and immunostained for GAD and parvalbumin to assess the location and extent of lesions accurately. RESULTS: Alterations in ABR variables depended on the type of lesion and post-surgery time of ABR recordings. Accordingly, bilateral ablations caused a statistically significant increase in thresholds at PSD1 and 7 and a decrease in waves amplitudes at PSD1 that recover at PSD7. No effects on latency were noted at PSD1 and 7, whilst recordings at PSD15 and 30 showed statistically significant decreases in latency. Conversely, unilateral ablations had no effect on auditory thresholds or latencies, while wave amplitudes only decreased at PSD1 strictly in the ipsilateral ear. CONCLUSION: Post-lesion plasticity in the auditory system acts in two time periods: short-term period of decreased sound sensitivity (until PSD7), most likely resulting from axonal degeneration; and a long-term period (up to PSD7), with changes in latency responses and recovery of thresholds and amplitudes values. The cerebral cortex may have a net positive gain on the auditory pathway response to sound.
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spelling pubmed-37748002013-09-24 Long-Term Evolution of Brainstem Electrical Evoked Responses to Sound after Restricted Ablation of the Auditory Cortex Lamas, Verónica Alvarado, Juan C. Carro, Juan Merchán, Miguel A. PLoS One Research Article INTRODUCTION: This study aimed to assess the top-down control of sound processing in the auditory brainstem of rats. Short latency evoked responses were analyzed after unilateral or bilateral ablation of auditory cortex. This experimental paradigm was also used towards analyzing the long-term evolution of post-lesion plasticity in the auditory system and its ability to self-repair. METHOD: Auditory cortex lesions were performed in rats by stereotactically guided fine-needle aspiration of the cerebrocortical surface. Auditory Brainstem Responses (ABR) were recorded at post-surgery day (PSD) 1, 7, 15 and 30. Recordings were performed under closed-field conditions, using click trains at different sound intensity levels, followed by statistical analysis of threshold values and ABR amplitude and latency variables. Subsequently, brains were sectioned and immunostained for GAD and parvalbumin to assess the location and extent of lesions accurately. RESULTS: Alterations in ABR variables depended on the type of lesion and post-surgery time of ABR recordings. Accordingly, bilateral ablations caused a statistically significant increase in thresholds at PSD1 and 7 and a decrease in waves amplitudes at PSD1 that recover at PSD7. No effects on latency were noted at PSD1 and 7, whilst recordings at PSD15 and 30 showed statistically significant decreases in latency. Conversely, unilateral ablations had no effect on auditory thresholds or latencies, while wave amplitudes only decreased at PSD1 strictly in the ipsilateral ear. CONCLUSION: Post-lesion plasticity in the auditory system acts in two time periods: short-term period of decreased sound sensitivity (until PSD7), most likely resulting from axonal degeneration; and a long-term period (up to PSD7), with changes in latency responses and recovery of thresholds and amplitudes values. The cerebral cortex may have a net positive gain on the auditory pathway response to sound. Public Library of Science 2013-09-16 /pmc/articles/PMC3774800/ /pubmed/24066057 http://dx.doi.org/10.1371/journal.pone.0073585 Text en © 2013 Lamas et al http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are properly credited.
spellingShingle Research Article
Lamas, Verónica
Alvarado, Juan C.
Carro, Juan
Merchán, Miguel A.
Long-Term Evolution of Brainstem Electrical Evoked Responses to Sound after Restricted Ablation of the Auditory Cortex
title Long-Term Evolution of Brainstem Electrical Evoked Responses to Sound after Restricted Ablation of the Auditory Cortex
title_full Long-Term Evolution of Brainstem Electrical Evoked Responses to Sound after Restricted Ablation of the Auditory Cortex
title_fullStr Long-Term Evolution of Brainstem Electrical Evoked Responses to Sound after Restricted Ablation of the Auditory Cortex
title_full_unstemmed Long-Term Evolution of Brainstem Electrical Evoked Responses to Sound after Restricted Ablation of the Auditory Cortex
title_short Long-Term Evolution of Brainstem Electrical Evoked Responses to Sound after Restricted Ablation of the Auditory Cortex
title_sort long-term evolution of brainstem electrical evoked responses to sound after restricted ablation of the auditory cortex
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3774800/
https://www.ncbi.nlm.nih.gov/pubmed/24066057
http://dx.doi.org/10.1371/journal.pone.0073585
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