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Extinction recall of fear memories formed before stress is not affected despite higher theta activity in the amygdala

Stress is known to exert its detrimental effects not only by enhancing fear, but also by impairing its extinction. However, in earlier studies stress exposure preceded both processes. Thus, compared to unstressed animals, stressed animals had to extinguish fear memories that were strengthened by pri...

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Detalles Bibliográficos
Autores principales: Rahman, Mohammed Mostafizur, Shukla, Ashutosh, Chattarji, Sumantra
Formato: Online Artículo Texto
Lenguaje:English
Publicado: eLife Sciences Publications, Ltd 2018
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6125126/
https://www.ncbi.nlm.nih.gov/pubmed/30102149
http://dx.doi.org/10.7554/eLife.35450
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author Rahman, Mohammed Mostafizur
Shukla, Ashutosh
Chattarji, Sumantra
author_facet Rahman, Mohammed Mostafizur
Shukla, Ashutosh
Chattarji, Sumantra
author_sort Rahman, Mohammed Mostafizur
collection PubMed
description Stress is known to exert its detrimental effects not only by enhancing fear, but also by impairing its extinction. However, in earlier studies stress exposure preceded both processes. Thus, compared to unstressed animals, stressed animals had to extinguish fear memories that were strengthened by prior exposure to stress. Here, we dissociate the two processes to examine if stress specifically impairs the acquisition and recall of fear extinction. Strikingly, when fear memories were formed before stress exposure, thereby allowing animals to initiate extinction from comparable levels of fear, recall of fear extinction was unaffected. Despite this, we observed a persistent increase in theta activity in the BLA. Theta activity in the mPFC, by contrast, was normal. Stress also disrupted mPFC-BLA theta-frequency synchrony and directional coupling. Thus, in the absence of the fear-enhancing effects of stress, the expression of fear during and after extinction reflects normal regulation of theta activity in the mPFC, not theta hyperactivity in the amygdala.
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spelling pubmed-61251262018-09-07 Extinction recall of fear memories formed before stress is not affected despite higher theta activity in the amygdala Rahman, Mohammed Mostafizur Shukla, Ashutosh Chattarji, Sumantra eLife Neuroscience Stress is known to exert its detrimental effects not only by enhancing fear, but also by impairing its extinction. However, in earlier studies stress exposure preceded both processes. Thus, compared to unstressed animals, stressed animals had to extinguish fear memories that were strengthened by prior exposure to stress. Here, we dissociate the two processes to examine if stress specifically impairs the acquisition and recall of fear extinction. Strikingly, when fear memories were formed before stress exposure, thereby allowing animals to initiate extinction from comparable levels of fear, recall of fear extinction was unaffected. Despite this, we observed a persistent increase in theta activity in the BLA. Theta activity in the mPFC, by contrast, was normal. Stress also disrupted mPFC-BLA theta-frequency synchrony and directional coupling. Thus, in the absence of the fear-enhancing effects of stress, the expression of fear during and after extinction reflects normal regulation of theta activity in the mPFC, not theta hyperactivity in the amygdala. eLife Sciences Publications, Ltd 2018-08-13 /pmc/articles/PMC6125126/ /pubmed/30102149 http://dx.doi.org/10.7554/eLife.35450 Text en © 2018, Rahman et al http://creativecommons.org/licenses/by/4.0/ http://creativecommons.org/licenses/by/4.0/This article is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use and redistribution provided that the original author and source are credited.
spellingShingle Neuroscience
Rahman, Mohammed Mostafizur
Shukla, Ashutosh
Chattarji, Sumantra
Extinction recall of fear memories formed before stress is not affected despite higher theta activity in the amygdala
title Extinction recall of fear memories formed before stress is not affected despite higher theta activity in the amygdala
title_full Extinction recall of fear memories formed before stress is not affected despite higher theta activity in the amygdala
title_fullStr Extinction recall of fear memories formed before stress is not affected despite higher theta activity in the amygdala
title_full_unstemmed Extinction recall of fear memories formed before stress is not affected despite higher theta activity in the amygdala
title_short Extinction recall of fear memories formed before stress is not affected despite higher theta activity in the amygdala
title_sort extinction recall of fear memories formed before stress is not affected despite higher theta activity in the amygdala
topic Neuroscience
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6125126/
https://www.ncbi.nlm.nih.gov/pubmed/30102149
http://dx.doi.org/10.7554/eLife.35450
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