| Summary: | 碩士 === 國立陽明大學 === 神經科學研究所 === 95 === Neuroanatomical connection is crucial to the understanding of brain function. The language anatomical model proposed that Broca’s area located in the inferior frontal lobe and Wernicke’s area located in the superior temporal gyrus, both were connected through the arcuate fasciculus, which functions in fast, automatic word repetition. Furthermore, the supramarginal gyrus has been highlighted the importance for phonological processing in recent neuroimaging studies.
The aim of this study is to estimate the corticocortical connection of language areas via diffusion MRI. Diffusion MRI is a non-invasive technique for in vivo measurement of microstructural properties of brain white matter. Integrated with fiber tractography algorithm, there can be visualized the three-dimensional (3D) pathways of white matter tracts.
In this study, diffusion tensor imaging and q-ball imaging were performed on the language related cerebral cortex to map the corticocortical connection. The results show that language related areas connected by two parallel pathways: a direct way runs medially and corresponds with classical descriptions of the arcuate fasciculus; an indirect pathway runs laterally and is composed of an anterior segment connecting parietal and frontal regions, and a posterior segment connecting temporal and parietal regions. And the pathways shown by tractography results are closely related to Wernicke-Lichtheim model.
In conclusion, this study uses tractography to visualize the network of connections relating to language in human brain. In the future, combining diffusion MRI with function MRI or MEG might be offset the lack of language activated cortex area and temporal resolution of diffusion MRI, and further, extended to interpretation Connectionist model of language.
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