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Connectivity Gradient in the Human Left Inferior Frontal Gyrus: Intraoperative Cortico-Cortical Evoked Potential Study.

Accepted version
Peer-reviewed

Type

Article

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Authors

Nakae, Takuro 
Matsumoto, Riki 
Kunieda, Takeharu 
Arakawa, Yoshiki 
Kobayashi, Katsuya 

Abstract

In the dual-stream model of language processing, the exact connectivity of the ventral stream to the anterior temporal lobe remains elusive. To investigate the connectivity between the inferior frontal gyrus (IFG) and the lateral part of the temporal and parietal lobes, we integrated spatiotemporal profiles of cortico-cortical evoked potentials (CCEPs) recorded intraoperatively in 14 patients who had undergone surgical resection for a brain tumor or epileptic focus. Four-dimensional visualization of the combined CCEP data showed that the pars opercularis (Broca's area) is connected to the posterior temporal cortices and the supramarginal gyrus, whereas the pars orbitalis is connected to the anterior lateral temporal cortices and angular gyrus. Quantitative topographical analysis of CCEP connectivity confirmed an anterior-posterior gradient of connectivity from IFG stimulus sites to the temporal response sites. Reciprocality analysis indicated that the anterior part of the IFG is bidirectionally connected to the temporal or parietal area. This study shows that each IFG subdivision has different connectivity to the temporal lobe with an anterior-posterior gradient and supports the classical connectivity concept of Dejerine; that is, the frontal lobe is connected to the temporal lobe through the arcuate fasciculus and also a double fan-shaped structure anchored at the limen insulae.

Description

Keywords

4D visualization, cortico-cortical evoked potential, dual-stream language model, fronto-temporal radiation, Adult, Aged, Brain Mapping, Cerebral Cortex, Comprehension, Electrocorticography, Evoked Potentials, Female, Humans, Language, Male, Middle Aged, Neural Pathways, Prefrontal Cortex, Semantics, Speech Perception

Journal Title

Cereb Cortex

Conference Name

Journal ISSN

1047-3211
1460-2199

Volume Title

30

Publisher

Oxford University Press (OUP)

Rights

All rights reserved
Sponsorship
MRC (Unknown)
Medical Research Council (MR/R023883/1)