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Duality of Function: Activation for Meaningless Nonwords and Semantic Codes in the Same Brain Areas

Studies of the neural substrates of semantic (word meaning) processing have typically focused on semantic manipulations, with less consideration for potential differences in difficulty across conditions. While the idea that particular brain regions can support multiple functions is widely accepted,...

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Autores principales: Mattheiss, Samantha R, Levinson, Hillary, Graves, William W
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Oxford University Press 2018
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5998986/
https://www.ncbi.nlm.nih.gov/pubmed/29901789
http://dx.doi.org/10.1093/cercor/bhy053
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author Mattheiss, Samantha R
Levinson, Hillary
Graves, William W
author_facet Mattheiss, Samantha R
Levinson, Hillary
Graves, William W
author_sort Mattheiss, Samantha R
collection PubMed
description Studies of the neural substrates of semantic (word meaning) processing have typically focused on semantic manipulations, with less consideration for potential differences in difficulty across conditions. While the idea that particular brain regions can support multiple functions is widely accepted, studies of specific cognitive domains rarely test for co-location with other functions. Here we start with standard univariate analyses comparing words to meaningless nonwords, replicating our recent finding that this contrast can activate task-positive regions for words, and default-mode regions in the putative semantic network for nonwords, pointing to difficulty effects. Critically, this was followed up with a multivariate analysis to test whether the same areas activated for meaningless nonwords contained semantic information sufficient to distinguish high- from low-imageability words. Indeed, this classification was performed reliably better than chance at 75% accuracy. This is compatible with two non-exclusive interpretations. Numerous areas in the default-mode network are task-negative in the sense of activating for less demanding conditions, and the same areas contain information supporting semantic cognition. Therefore, while areas of the default mode network have been hypothesized to support semantic cognition, we offer evidence that these areas can respond to both domain-general difficulty effects, and to specific aspects of semantics.
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spelling pubmed-59989862018-06-18 Duality of Function: Activation for Meaningless Nonwords and Semantic Codes in the Same Brain Areas Mattheiss, Samantha R Levinson, Hillary Graves, William W Cereb Cortex Original Articles Studies of the neural substrates of semantic (word meaning) processing have typically focused on semantic manipulations, with less consideration for potential differences in difficulty across conditions. While the idea that particular brain regions can support multiple functions is widely accepted, studies of specific cognitive domains rarely test for co-location with other functions. Here we start with standard univariate analyses comparing words to meaningless nonwords, replicating our recent finding that this contrast can activate task-positive regions for words, and default-mode regions in the putative semantic network for nonwords, pointing to difficulty effects. Critically, this was followed up with a multivariate analysis to test whether the same areas activated for meaningless nonwords contained semantic information sufficient to distinguish high- from low-imageability words. Indeed, this classification was performed reliably better than chance at 75% accuracy. This is compatible with two non-exclusive interpretations. Numerous areas in the default-mode network are task-negative in the sense of activating for less demanding conditions, and the same areas contain information supporting semantic cognition. Therefore, while areas of the default mode network have been hypothesized to support semantic cognition, we offer evidence that these areas can respond to both domain-general difficulty effects, and to specific aspects of semantics. Oxford University Press 2018-07 2018-04-18 /pmc/articles/PMC5998986/ /pubmed/29901789 http://dx.doi.org/10.1093/cercor/bhy053 Text en © The Author(s) 2018. Published by Oxford University Press. http://creativecommons.org/licenses/by-nc/4.0/ This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0/), which permits non-commercial re-use, distribution, and reproduction in any medium, provided the original work is properly cited. For commercial re-use, please contact journals.permissions@oup.com
spellingShingle Original Articles
Mattheiss, Samantha R
Levinson, Hillary
Graves, William W
Duality of Function: Activation for Meaningless Nonwords and Semantic Codes in the Same Brain Areas
title Duality of Function: Activation for Meaningless Nonwords and Semantic Codes in the Same Brain Areas
title_full Duality of Function: Activation for Meaningless Nonwords and Semantic Codes in the Same Brain Areas
title_fullStr Duality of Function: Activation for Meaningless Nonwords and Semantic Codes in the Same Brain Areas
title_full_unstemmed Duality of Function: Activation for Meaningless Nonwords and Semantic Codes in the Same Brain Areas
title_short Duality of Function: Activation for Meaningless Nonwords and Semantic Codes in the Same Brain Areas
title_sort duality of function: activation for meaningless nonwords and semantic codes in the same brain areas
topic Original Articles
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5998986/
https://www.ncbi.nlm.nih.gov/pubmed/29901789
http://dx.doi.org/10.1093/cercor/bhy053
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