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HIPPOCAMPAL GLUTAMATE MODULATION DURING MEMORY ENCODING: ASSOCIATION WITH AGE AND SUBFIELD VOLUMES

Hippocampal glutamatergic activity plays a pivotal role in memory consolidation, including the ability to form novel associations that declines with age. To test whether glutamatergic dysfunction may underpin age-related memory declines, we examined in vivo age differences in hippocampal glutamate m...

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Autores principales: Anand, Chaitali, Homayouni, Roya, Yu, Qijing, Ramesh, Sruthi, Khatib, Dalal, Dahle, Cheryl, Stanley, Jeffrey, Raz, Naftali
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Oxford University Press 2019
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6845574/
http://dx.doi.org/10.1093/geroni/igz038.3095
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author Anand, Chaitali
Homayouni, Roya
Yu, Qijing
Ramesh, Sruthi
Khatib, Dalal
Dahle, Cheryl
Stanley, Jeffrey
Raz, Naftali
author_facet Anand, Chaitali
Homayouni, Roya
Yu, Qijing
Ramesh, Sruthi
Khatib, Dalal
Dahle, Cheryl
Stanley, Jeffrey
Raz, Naftali
author_sort Anand, Chaitali
collection PubMed
description Hippocampal glutamatergic activity plays a pivotal role in memory consolidation, including the ability to form novel associations that declines with age. To test whether glutamatergic dysfunction may underpin age-related memory declines, we examined in vivo age differences in hippocampal glutamate modulation during encoding of associations, and its relationship with hippocampal subfield volumes. Proton functional magnetic resonance spectroscopy was performed on 32 young (25.1±2.8 years; 18 females) and 16 older (65.9±2.7 years; 7 females) adults to measure changes in hippocampal (randomly assigned right or left) glutamate during an object-location paired association learning task (with 12 cycles of encoding-retrieval epochs). Volumes of the dentate gyrus&CA3, CA1, subiculum, and entorhinal cortex were manually measured from T2-weighted MRI images. Memory performance differed between the age-groups [F(1, 46)=8.56, p<.01], with the older attaining a lower asymptote [t(46)=2.93, p<.05] compared to the younger. Age differences in glutamate were observed only during encoding (age-group x epoch: F(3,137)=5.28, p<.01), and varied over the epochs. Young adults showed increased glutamate during the first four encoding epochs of each cycle, with levels remaining high thereafter. Old adults evidenced a decrease in glutamate during the first four epochs, and a slow, sustained ramping-up afterwards. Including both age-groups, the maximum change in glutamate, calculated using the maximum and minimum levels during encoding, was positively associated with CA1 [F(2,39)=4.28, p<.05] and the dentate gyrus&CA3 volume [F(2,39)=4.4, p<.05], after correcting for multiple comparisons. Glutamate modulation specific to encoding may underlie age-related memory declines and be related to selected hippocampal subfield volumes.
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spelling pubmed-68455742019-11-18 HIPPOCAMPAL GLUTAMATE MODULATION DURING MEMORY ENCODING: ASSOCIATION WITH AGE AND SUBFIELD VOLUMES Anand, Chaitali Homayouni, Roya Yu, Qijing Ramesh, Sruthi Khatib, Dalal Dahle, Cheryl Stanley, Jeffrey Raz, Naftali Innov Aging Session Lb935 (Late Breaking Poster) Hippocampal glutamatergic activity plays a pivotal role in memory consolidation, including the ability to form novel associations that declines with age. To test whether glutamatergic dysfunction may underpin age-related memory declines, we examined in vivo age differences in hippocampal glutamate modulation during encoding of associations, and its relationship with hippocampal subfield volumes. Proton functional magnetic resonance spectroscopy was performed on 32 young (25.1±2.8 years; 18 females) and 16 older (65.9±2.7 years; 7 females) adults to measure changes in hippocampal (randomly assigned right or left) glutamate during an object-location paired association learning task (with 12 cycles of encoding-retrieval epochs). Volumes of the dentate gyrus&CA3, CA1, subiculum, and entorhinal cortex were manually measured from T2-weighted MRI images. Memory performance differed between the age-groups [F(1, 46)=8.56, p<.01], with the older attaining a lower asymptote [t(46)=2.93, p<.05] compared to the younger. Age differences in glutamate were observed only during encoding (age-group x epoch: F(3,137)=5.28, p<.01), and varied over the epochs. Young adults showed increased glutamate during the first four encoding epochs of each cycle, with levels remaining high thereafter. Old adults evidenced a decrease in glutamate during the first four epochs, and a slow, sustained ramping-up afterwards. Including both age-groups, the maximum change in glutamate, calculated using the maximum and minimum levels during encoding, was positively associated with CA1 [F(2,39)=4.28, p<.05] and the dentate gyrus&CA3 volume [F(2,39)=4.4, p<.05], after correcting for multiple comparisons. Glutamate modulation specific to encoding may underlie age-related memory declines and be related to selected hippocampal subfield volumes. Oxford University Press 2019-11-08 /pmc/articles/PMC6845574/ http://dx.doi.org/10.1093/geroni/igz038.3095 Text en © The Author(s) 2019. Published by Oxford University Press on behalf of The Gerontological Society of America. http://creativecommons.org/licenses/by/4.0/ This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited.
spellingShingle Session Lb935 (Late Breaking Poster)
Anand, Chaitali
Homayouni, Roya
Yu, Qijing
Ramesh, Sruthi
Khatib, Dalal
Dahle, Cheryl
Stanley, Jeffrey
Raz, Naftali
HIPPOCAMPAL GLUTAMATE MODULATION DURING MEMORY ENCODING: ASSOCIATION WITH AGE AND SUBFIELD VOLUMES
title HIPPOCAMPAL GLUTAMATE MODULATION DURING MEMORY ENCODING: ASSOCIATION WITH AGE AND SUBFIELD VOLUMES
title_full HIPPOCAMPAL GLUTAMATE MODULATION DURING MEMORY ENCODING: ASSOCIATION WITH AGE AND SUBFIELD VOLUMES
title_fullStr HIPPOCAMPAL GLUTAMATE MODULATION DURING MEMORY ENCODING: ASSOCIATION WITH AGE AND SUBFIELD VOLUMES
title_full_unstemmed HIPPOCAMPAL GLUTAMATE MODULATION DURING MEMORY ENCODING: ASSOCIATION WITH AGE AND SUBFIELD VOLUMES
title_short HIPPOCAMPAL GLUTAMATE MODULATION DURING MEMORY ENCODING: ASSOCIATION WITH AGE AND SUBFIELD VOLUMES
title_sort hippocampal glutamate modulation during memory encoding: association with age and subfield volumes
topic Session Lb935 (Late Breaking Poster)
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6845574/
http://dx.doi.org/10.1093/geroni/igz038.3095
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