Combined DTI Tractography and Functional MRI Study of the Language Connectome in Healthy Volunteers: Extensive Mapping of White Matter Fascicles and Cortical ActivationsReportar como inadecuado




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Despite a better understanding of brain language organization into large-scale cortical networks, the underlying white matter WM connectivity is still not mastered. Here we combined diffusion tensor imaging DTI fiber tracking FT and language functional magnetic resonance imaging fMRI in twenty healthy subjects to gain new insights into the macroscopic structural connectivity of language. Eight putative WM fascicles for language were probed using a deterministic DTI-FT technique: the arcuate fascicle AF, superior longitudinal fascicle SLF, uncinate fascicle UF, temporo-occipital fascicle, inferior fronto-occipital fascicle IFOF, middle longitudinal fascicle MdLF, frontal aslant fascicle and operculopremotor fascicle. Specific measurements i.e. volume, length, fractional anisotropy and precise cortical terminations were derived for each WM fascicle within both hemispheres. Connections between these WM fascicles and fMRI activations were studied to determine which WM fascicles are related to language. WM fascicle volumes showed asymmetries: leftward for the AF, temporoparietal segment of SLF and UF, and rightward for the frontoparietal segment of the SLF. The lateralization of the AF, IFOF and MdLF extended to differences in patterns of anatomical connections, which may relate to specific hemispheric abilities. The leftward asymmetry of the AF was correlated to the leftward asymmetry of fMRI activations, suggesting that the lateralization of the AF is a structural substrate of hemispheric language dominance. We found consistent connections between fMRI activations and terminations of the eight WM fascicles, providing a detailed description of the language connectome. WM fascicle terminations were also observed beyond fMRI-confirmed language areas and reached numerous cortical areas involved in different functional brain networks. These findings suggest that the reported WM fascicles are not exclusively involved in language and might be related to other cognitive functions such as visual recognition, spatial attention, executive functions, memory, and processing of emotional and behavioral aspects.



Autor: François Vassal , Fabien Schneider , Claire Boutet , Betty Jean , Anna Sontheimer , Jean-Jacques Lemaire

Fuente: http://plos.srce.hr/



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