Finding Cortical Subregions Regarding the Dorsal Language Pathway Based on the Structural Connectivity

Young-Eun Hwang; Young-Bo Kim; Young-Don Son

doi:10.3389/fnhum.2022.784340

Finding Cortical Subregions Regarding the Dorsal Language Pathway Based on the Structural Connectivity

Front Hum Neurosci. 2022 May 2:16:784340. doi: 10.3389/fnhum.2022.784340. eCollection 2022.

Authors

Young-Eun Hwang^{1

2

3}, Young-Bo Kim⁴, Young-Don Son^{2

3}

Affiliations

¹ Neuroscience Convergence Center, Korea University, Seoul, South Korea.
² Department of Health Sciences and Technology, Gachion Advanced Institute for Health Sciences & Technology (GAHIST), Gachon University, Incheon, South Korea.
³ Department of Biomedical Engineering, Gachon University, Incheon, South Korea.
⁴ Department of Neurosurgery, Gil Medical Center, College of Medicine, Gachon University, Incheon, South Korea.

Abstract

Although the language-related fiber pathways in the human brain, such as the superior longitudinal fasciculus (SLF) and arcuate fasciculus (AF), are already well-known, understanding more sophisticated cortical regions connected by the fiber tracts is essential to scrutinize the structural connectivity of language circuits. With the regions of interest that were selected based on the Brainnetome atlas, the fiber orientation distribution estimation method for tractography was used to produce further elaborate connectivity information. The results indicated that both fiber bundles had two distinct connections with the prefrontal cortex (PFC). The SLF-II and dorsal AF are mainly connected to the rostrodorsal part of the inferior parietal cortex (IPC) and lateral part of the fusiform gyrus with the inferior frontal junction (IFJ), respectively. In contrast, the SLF-III and ventral AF were primarily linked to the anterior part of the supramarginal gyrus and superior part of the temporal cortex with the inferior frontal cortex, including the Broca's area. Moreover, the IFJ in the PFC, which has rarely been emphasized as a language-related subregion, also had the strongest connectivity with the previously known language-related subregions among the PFC; consequently, we proposed that these specific regions are interconnected via the SLF and AF within the PFC, IPC, and temporal cortex as language-related circuitry.

Keywords: arcuate fasciculus (AF); connectome; diffusion-weighted magnetic resonance imaging (dMRI); language pathway; superior longitudinal fasciculus (SLF); tractography.