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Predictability matters: role of the hippocampus and prefrontal cortex in disambiguation of overlapping sequences

Previous research has demonstrated that areas in the medial temporal lobe and prefrontal cortex (PFC) show increased activation during retrieval of overlapping sequences. In this study, we designed a task in which degree of overlap varied between conditions in order to parse out the contributions of...

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Detalles Bibliográficos
Autores principales: Cohen, Justine E., Ross, Robert S., Stern, Chantal E.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Cold Spring Harbor Laboratory Press 2018
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6049392/
https://www.ncbi.nlm.nih.gov/pubmed/30012878
http://dx.doi.org/10.1101/lm.047175.117
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author Cohen, Justine E.
Ross, Robert S.
Stern, Chantal E.
author_facet Cohen, Justine E.
Ross, Robert S.
Stern, Chantal E.
author_sort Cohen, Justine E.
collection PubMed
description Previous research has demonstrated that areas in the medial temporal lobe and prefrontal cortex (PFC) show increased activation during retrieval of overlapping sequences. In this study, we designed a task in which degree of overlap varied between conditions in order to parse out the contributions of hippocampal and prefrontal subregions as overlap between associations increased. In the task, participants learned sequential associations consisting of a picture frame, a face within the picture frame, and an outdoor scene. The control condition consisted of a single frame-face-scene sequence. In the low overlap condition, each frame was paired with two faces and two scenes. In the high overlap condition, each frame was paired with four faces and four scenes. In all conditions the correct scene was chosen among four possible scenes and was dependent on the frame and face that preceded the choice point. One day after training, participants were tested on the retrieval of learned sequences during fMRI scanning. Results showed that the middle and posterior hippocampus (HC) was active at times when participants acquired information that increased predictability of the correct response in the overlapping sequences. Activation of dorsolateral PFC occurred at time points when the participant was able to ascertain which set of sequences the correct response belonged to. The ventrolateral PFC was active when inhibition was required, either of irrelevant stimuli or incorrect responses. These results indicate that areas of lateral PFC work in concert with the HC to disambiguate between overlapping sequences and that sequence predictability is key to when specific brain regions become active.
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spelling pubmed-60493922019-08-01 Predictability matters: role of the hippocampus and prefrontal cortex in disambiguation of overlapping sequences Cohen, Justine E. Ross, Robert S. Stern, Chantal E. Learn Mem Research Previous research has demonstrated that areas in the medial temporal lobe and prefrontal cortex (PFC) show increased activation during retrieval of overlapping sequences. In this study, we designed a task in which degree of overlap varied between conditions in order to parse out the contributions of hippocampal and prefrontal subregions as overlap between associations increased. In the task, participants learned sequential associations consisting of a picture frame, a face within the picture frame, and an outdoor scene. The control condition consisted of a single frame-face-scene sequence. In the low overlap condition, each frame was paired with two faces and two scenes. In the high overlap condition, each frame was paired with four faces and four scenes. In all conditions the correct scene was chosen among four possible scenes and was dependent on the frame and face that preceded the choice point. One day after training, participants were tested on the retrieval of learned sequences during fMRI scanning. Results showed that the middle and posterior hippocampus (HC) was active at times when participants acquired information that increased predictability of the correct response in the overlapping sequences. Activation of dorsolateral PFC occurred at time points when the participant was able to ascertain which set of sequences the correct response belonged to. The ventrolateral PFC was active when inhibition was required, either of irrelevant stimuli or incorrect responses. These results indicate that areas of lateral PFC work in concert with the HC to disambiguate between overlapping sequences and that sequence predictability is key to when specific brain regions become active. Cold Spring Harbor Laboratory Press 2018-08 /pmc/articles/PMC6049392/ /pubmed/30012878 http://dx.doi.org/10.1101/lm.047175.117 Text en © 2018 Cohen et al.; Published by Cold Spring Harbor Laboratory Press http://creativecommons.org/licenses/by-nc/4.0/ This article is distributed exclusively by Cold Spring Harbor Laboratory Press for the first 12 months after the full-issue publication date (see http://learnmem.cshlp.org/site/misc/terms.xhtml). After 12 months, it is available under a Creative Commons License (Attribution-NonCommercial 4.0 International), as described at http://creativecommons.org/licenses/by-nc/4.0/.
spellingShingle Research
Cohen, Justine E.
Ross, Robert S.
Stern, Chantal E.
Predictability matters: role of the hippocampus and prefrontal cortex in disambiguation of overlapping sequences
title Predictability matters: role of the hippocampus and prefrontal cortex in disambiguation of overlapping sequences
title_full Predictability matters: role of the hippocampus and prefrontal cortex in disambiguation of overlapping sequences
title_fullStr Predictability matters: role of the hippocampus and prefrontal cortex in disambiguation of overlapping sequences
title_full_unstemmed Predictability matters: role of the hippocampus and prefrontal cortex in disambiguation of overlapping sequences
title_short Predictability matters: role of the hippocampus and prefrontal cortex in disambiguation of overlapping sequences
title_sort predictability matters: role of the hippocampus and prefrontal cortex in disambiguation of overlapping sequences
topic Research
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6049392/
https://www.ncbi.nlm.nih.gov/pubmed/30012878
http://dx.doi.org/10.1101/lm.047175.117
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