Functional Heterogeneity within the Default Network during Semantic Processing and Speech Production
This fMRI study investigated the functional heterogeneity of the core nodes of the default mode network (DMN) during language processing. The core nodes of the DMN were defined as task-induced deactivations over multiple tasks in 94 healthy subjects. We used a factorial design that manipulated diffe...
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| Format: | Online |
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Frontiers Research Foundation
2012
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| Online Access: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3417693/ |
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pubmed-34176932012-08-17 Functional Heterogeneity within the Default Network during Semantic Processing and Speech Production Seghier, Mohamed L. Price, Cathy J. Psychology This fMRI study investigated the functional heterogeneity of the core nodes of the default mode network (DMN) during language processing. The core nodes of the DMN were defined as task-induced deactivations over multiple tasks in 94 healthy subjects. We used a factorial design that manipulated different tasks (semantic matching or speech production) and stimuli (familiar words and objects or unfamiliar stimuli), alternating with periods of fixation/rest. Our findings revealed several consistent effects in the DMN, namely less deactivations in the left inferior parietal lobule during semantic than perceptual matching in parallel with greater deactivations during semantic matching in anterior subdivisions of the posterior cingulate cortex (PCC) and the ventromedial prefrontal cortex (MPFC). This suggests that, when the brain is engaged in effortful semantic tasks, a part of the DMN in the left angular gyrus was less deactivated as five other nodes of the DMN were more deactivated. These five DMN areas, where deactivation was greater for semantic than perceptual matching, were further differentiated because deactivation was greater in (i) posterior ventral MPFC for speech production relative to semantic matching, (ii) posterior precuneus and PCC for perceptual processing relative to speech production, and (iii) right inferior parietal cortex for pictures of objects relative to written words during both naming and semantic decisions. Our results thus highlight that task difficulty alone cannot fully explain the functional variability in task-induced deactivations. Together these results emphasize that core nodes within the DMN are functionally heterogeneous and differentially sensitive to the type of language processing. Frontiers Research Foundation 2012-08-13 /pmc/articles/PMC3417693/ /pubmed/22905029 http://dx.doi.org/10.3389/fpsyg.2012.00281 Text en Copyright © 2012 Seghier and Price. http://www.frontiersin.org/licenseagreement This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in other forums, provided the original authors and source are credited and subject to any copyright notices concerning any third-party graphics etc. |
| repository_type |
Open Access Journal |
| institution_category |
Foreign Institution |
| institution |
US National Center for Biotechnology Information |
| building |
NCBI PubMed |
| collection |
Online Access |
| language |
English |
| format |
Online |
| author |
Seghier, Mohamed L. Price, Cathy J. |
| spellingShingle |
Seghier, Mohamed L. Price, Cathy J. Functional Heterogeneity within the Default Network during Semantic Processing and Speech Production |
| author_facet |
Seghier, Mohamed L. Price, Cathy J. |
| author_sort |
Seghier, Mohamed L. |
| title |
Functional Heterogeneity within the Default Network during Semantic Processing and Speech Production |
| title_short |
Functional Heterogeneity within the Default Network during Semantic Processing and Speech Production |
| title_full |
Functional Heterogeneity within the Default Network during Semantic Processing and Speech Production |
| title_fullStr |
Functional Heterogeneity within the Default Network during Semantic Processing and Speech Production |
| title_full_unstemmed |
Functional Heterogeneity within the Default Network during Semantic Processing and Speech Production |
| title_sort |
functional heterogeneity within the default network during semantic processing and speech production |
| description |
This fMRI study investigated the functional heterogeneity of the core nodes of the default mode network (DMN) during language processing. The core nodes of the DMN were defined as task-induced deactivations over multiple tasks in 94 healthy subjects. We used a factorial design that manipulated different tasks (semantic matching or speech production) and stimuli (familiar words and objects or unfamiliar stimuli), alternating with periods of fixation/rest. Our findings revealed several consistent effects in the DMN, namely less deactivations in the left inferior parietal lobule during semantic than perceptual matching in parallel with greater deactivations during semantic matching in anterior subdivisions of the posterior cingulate cortex (PCC) and the ventromedial prefrontal cortex (MPFC). This suggests that, when the brain is engaged in effortful semantic tasks, a part of the DMN in the left angular gyrus was less deactivated as five other nodes of the DMN were more deactivated. These five DMN areas, where deactivation was greater for semantic than perceptual matching, were further differentiated because deactivation was greater in (i) posterior ventral MPFC for speech production relative to semantic matching, (ii) posterior precuneus and PCC for perceptual processing relative to speech production, and (iii) right inferior parietal cortex for pictures of objects relative to written words during both naming and semantic decisions. Our results thus highlight that task difficulty alone cannot fully explain the functional variability in task-induced deactivations. Together these results emphasize that core nodes within the DMN are functionally heterogeneous and differentially sensitive to the type of language processing. |
| publisher |
Frontiers Research Foundation |
| publishDate |
2012 |
| url |
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3417693/ |
| _version_ |
1611549288887746560 |