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Distinct roles for the anterior temporal lobe and angular gyrus in the spatiotemporal cortical semantic network.
- Source :
-
Cerebral cortex (New York, N.Y. : 1991) [Cereb Cortex] 2022 Oct 08; Vol. 32 (20), pp. 4549-4564. - Publication Year :
- 2022
-
Abstract
- Semantic knowledge is supported by numerous brain regions, but the spatiotemporal configuration of the network that links these areas remains an open question. The hub-and-spokes model posits that a central semantic hub coordinates this network. In this study, we explored distinct aspects that define a semantic hub, as reflected in the spatiotemporal modulation of neural activity and connectivity by semantic variables, from the earliest stages of semantic processing. We used source-reconstructed electro/magnetoencephalography, and investigated the concreteness contrast across three tasks. In a whole-cortex analysis, the left anterior temporal lobe (ATL) was the only area that showed modulation of evoked brain activity from 100 ms post-stimulus. Furthermore, using Dynamic Causal Modeling of the evoked responses, we investigated effective connectivity amongst the candidate semantic hub regions, that is, left ATL, supramarginal/angular gyrus (SMG/AG), middle temporal gyrus, and inferior frontal gyrus. We found that models with a single semantic hub showed the highest Bayesian evidence, and the hub region was found to change from ATL (within 250 ms) to SMG/AG (within 450 ms) over time. Our results support a single semantic hub view, with ATL showing sustained modulation of neural activity by semantics, and both ATL and AG underlying connectivity depending on the stage of semantic processing.<br /> (© The Author(s) 2022. Published by Oxford University Press.)
Details
- Language :
- English
- ISSN :
- 1460-2199
- Volume :
- 32
- Issue :
- 20
- Database :
- MEDLINE
- Journal :
- Cerebral cortex (New York, N.Y. : 1991)
- Publication Type :
- Academic Journal
- Accession number :
- 35094061
- Full Text :
- https://doi.org/10.1093/cercor/bhab501