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Posterior α EEG Dynamics Dissociate Current from Future Goals in Working Memory-Guided Visual Search

Current models of visual search assume that search is guided by an active visual working memory representation of what we are currently looking for. This attentional template for currently relevant stimuli can be dissociated from accessory memory representations that are only needed prospectively, f...

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Detalles Bibliográficos
Autores principales: de Vries, Ingmar E.J., van Driel, Joram, Olivers, Christian N.L.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Society for Neuroscience 2017
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5299573/
https://www.ncbi.nlm.nih.gov/pubmed/28069918
http://dx.doi.org/10.1523/JNEUROSCI.2945-16.2016
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author de Vries, Ingmar E.J.
van Driel, Joram
Olivers, Christian N.L.
author_facet de Vries, Ingmar E.J.
van Driel, Joram
Olivers, Christian N.L.
author_sort de Vries, Ingmar E.J.
collection PubMed
description Current models of visual search assume that search is guided by an active visual working memory representation of what we are currently looking for. This attentional template for currently relevant stimuli can be dissociated from accessory memory representations that are only needed prospectively, for a future task, and that should be prevented from guiding current attention. However, it remains unclear what electrophysiological mechanisms dissociate currently relevant (serving upcoming selection) from prospectively relevant memories (serving future selection). We measured EEG of 20 human subjects while they performed two consecutive visual search tasks. Before the search tasks, a cue instructed observers which item to look for first (current template) and which second (prospective template). During the delay leading up to the first search display, we found clear suppression of α band (8–14 Hz) activity in regions contralateral to remembered items, comprising both local power and interregional phase synchronization within a posterior parietal network. Importantly, these lateralization effects were stronger when the memory item was currently relevant (i.e., for the first search) compared with when it was prospectively relevant (i.e., for the second search), consistent with current templates being prioritized over future templates. In contrast, event-related potential analysis revealed that the contralateral delay activity was similar for all conditions, suggesting no difference in storage. Together, these findings support the idea that posterior α oscillations represent a state of increased processing or excitability in task-relevant cortical regions, and reflect enhanced cortical prioritization of memory representations that serve as a current selection filter. SIGNIFICANCE STATEMENT Our days are filled with looking for relevant objects while ignoring irrelevant visual information. Such visual search activity is thought to be driven by current goals activated in working memory. However, working memory not only serves current goals, but also future goals, with differential impact upon visual selection. Little is known about how the brain differentiates between current and future goals. Here we show, for the first time, that modulations of brain oscillations in the EEG α frequency band in posterior cortex can dissociate current from future search goals in working memory. Moreover, the dynamics of these oscillations uncover how we flexibly switch focus between memory representations. Together, we reveal how the brain assigns priority for selection.
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spelling pubmed-52995732017-03-01 Posterior α EEG Dynamics Dissociate Current from Future Goals in Working Memory-Guided Visual Search de Vries, Ingmar E.J. van Driel, Joram Olivers, Christian N.L. J Neurosci Research Articles Current models of visual search assume that search is guided by an active visual working memory representation of what we are currently looking for. This attentional template for currently relevant stimuli can be dissociated from accessory memory representations that are only needed prospectively, for a future task, and that should be prevented from guiding current attention. However, it remains unclear what electrophysiological mechanisms dissociate currently relevant (serving upcoming selection) from prospectively relevant memories (serving future selection). We measured EEG of 20 human subjects while they performed two consecutive visual search tasks. Before the search tasks, a cue instructed observers which item to look for first (current template) and which second (prospective template). During the delay leading up to the first search display, we found clear suppression of α band (8–14 Hz) activity in regions contralateral to remembered items, comprising both local power and interregional phase synchronization within a posterior parietal network. Importantly, these lateralization effects were stronger when the memory item was currently relevant (i.e., for the first search) compared with when it was prospectively relevant (i.e., for the second search), consistent with current templates being prioritized over future templates. In contrast, event-related potential analysis revealed that the contralateral delay activity was similar for all conditions, suggesting no difference in storage. Together, these findings support the idea that posterior α oscillations represent a state of increased processing or excitability in task-relevant cortical regions, and reflect enhanced cortical prioritization of memory representations that serve as a current selection filter. SIGNIFICANCE STATEMENT Our days are filled with looking for relevant objects while ignoring irrelevant visual information. Such visual search activity is thought to be driven by current goals activated in working memory. However, working memory not only serves current goals, but also future goals, with differential impact upon visual selection. Little is known about how the brain differentiates between current and future goals. Here we show, for the first time, that modulations of brain oscillations in the EEG α frequency band in posterior cortex can dissociate current from future search goals in working memory. Moreover, the dynamics of these oscillations uncover how we flexibly switch focus between memory representations. Together, we reveal how the brain assigns priority for selection. Society for Neuroscience 2017-02-08 /pmc/articles/PMC5299573/ /pubmed/28069918 http://dx.doi.org/10.1523/JNEUROSCI.2945-16.2016 Text en Copyright © 2017 de Vries et al. https://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License Creative Commons Attribution 4.0 International (https://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use, distribution and reproduction in any medium provided that the original work is properly attributed.
spellingShingle Research Articles
de Vries, Ingmar E.J.
van Driel, Joram
Olivers, Christian N.L.
Posterior α EEG Dynamics Dissociate Current from Future Goals in Working Memory-Guided Visual Search
title Posterior α EEG Dynamics Dissociate Current from Future Goals in Working Memory-Guided Visual Search
title_full Posterior α EEG Dynamics Dissociate Current from Future Goals in Working Memory-Guided Visual Search
title_fullStr Posterior α EEG Dynamics Dissociate Current from Future Goals in Working Memory-Guided Visual Search
title_full_unstemmed Posterior α EEG Dynamics Dissociate Current from Future Goals in Working Memory-Guided Visual Search
title_short Posterior α EEG Dynamics Dissociate Current from Future Goals in Working Memory-Guided Visual Search
title_sort posterior α eeg dynamics dissociate current from future goals in working memory-guided visual search
topic Research Articles
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5299573/
https://www.ncbi.nlm.nih.gov/pubmed/28069918
http://dx.doi.org/10.1523/JNEUROSCI.2945-16.2016
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