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Barking up the right tree: Univariate and multivariate fMRI analyses of homonym comprehension

Homonyms are a critical test case for investigating how the brain resolves ambiguity in language and, more generally, how context influences semantic processing. Previous neuroimaging studies have associated processing of homonyms with greater engagement of regions involved in executive control of s...

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Autores principales: Hoffman, Paul, Tamm, Andres
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Academic Press 2020
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7443701/
https://www.ncbi.nlm.nih.gov/pubmed/32534964
http://dx.doi.org/10.1016/j.neuroimage.2020.117050
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author Hoffman, Paul
Tamm, Andres
author_facet Hoffman, Paul
Tamm, Andres
author_sort Hoffman, Paul
collection PubMed
description Homonyms are a critical test case for investigating how the brain resolves ambiguity in language and, more generally, how context influences semantic processing. Previous neuroimaging studies have associated processing of homonyms with greater engagement of regions involved in executive control of semantic processing. However, the precise role of these areas and the involvement of semantic representational regions in homonym comprehension remain elusive. We addressed this by combining univariate and multivariate fMRI analyses of homonym processing. We tested whether multi-voxel activation patterns could discriminate between presentations of the same homonym in different contexts (e.g., bark following tree vs. bark following dog). The ventral anterior temporal lobe, implicated in semantic representation but not previously in homonym comprehension, showed this meaning-specific coding, despite not showing increased mean activation for homonyms. Within inferior frontal gyrus (IFG), a key site for semantic control, there was a dissociation between pars orbitalis, which also showed meaning-specific coding, and pars triangularis, which discriminated more generally between semantically related and unrelated word pairs. IFG effects were goal-dependent, only occurring when the task required semantic decisions, in line with a top-down control function. Finally, posterior middle temporal cortex showed a hybrid pattern of responses, supporting the idea that it acts as an interface between semantic representations and the control system. The study provides new evidence for context-dependent coding in the semantic system and clarifies the role of control regions in processing ambiguity. It also highlights the importance of combining univariate and multivariate neuroimaging data to fully elucidate the role of a brain region in semantic cognition.
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spelling pubmed-74437012020-10-01 Barking up the right tree: Univariate and multivariate fMRI analyses of homonym comprehension Hoffman, Paul Tamm, Andres Neuroimage Article Homonyms are a critical test case for investigating how the brain resolves ambiguity in language and, more generally, how context influences semantic processing. Previous neuroimaging studies have associated processing of homonyms with greater engagement of regions involved in executive control of semantic processing. However, the precise role of these areas and the involvement of semantic representational regions in homonym comprehension remain elusive. We addressed this by combining univariate and multivariate fMRI analyses of homonym processing. We tested whether multi-voxel activation patterns could discriminate between presentations of the same homonym in different contexts (e.g., bark following tree vs. bark following dog). The ventral anterior temporal lobe, implicated in semantic representation but not previously in homonym comprehension, showed this meaning-specific coding, despite not showing increased mean activation for homonyms. Within inferior frontal gyrus (IFG), a key site for semantic control, there was a dissociation between pars orbitalis, which also showed meaning-specific coding, and pars triangularis, which discriminated more generally between semantically related and unrelated word pairs. IFG effects were goal-dependent, only occurring when the task required semantic decisions, in line with a top-down control function. Finally, posterior middle temporal cortex showed a hybrid pattern of responses, supporting the idea that it acts as an interface between semantic representations and the control system. The study provides new evidence for context-dependent coding in the semantic system and clarifies the role of control regions in processing ambiguity. It also highlights the importance of combining univariate and multivariate neuroimaging data to fully elucidate the role of a brain region in semantic cognition. Academic Press 2020-10-01 /pmc/articles/PMC7443701/ /pubmed/32534964 http://dx.doi.org/10.1016/j.neuroimage.2020.117050 Text en © 2020 The Author(s) http://creativecommons.org/licenses/by/4.0/ This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Hoffman, Paul
Tamm, Andres
Barking up the right tree: Univariate and multivariate fMRI analyses of homonym comprehension
title Barking up the right tree: Univariate and multivariate fMRI analyses of homonym comprehension
title_full Barking up the right tree: Univariate and multivariate fMRI analyses of homonym comprehension
title_fullStr Barking up the right tree: Univariate and multivariate fMRI analyses of homonym comprehension
title_full_unstemmed Barking up the right tree: Univariate and multivariate fMRI analyses of homonym comprehension
title_short Barking up the right tree: Univariate and multivariate fMRI analyses of homonym comprehension
title_sort barking up the right tree: univariate and multivariate fmri analyses of homonym comprehension
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7443701/
https://www.ncbi.nlm.nih.gov/pubmed/32534964
http://dx.doi.org/10.1016/j.neuroimage.2020.117050
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