Powell H W Robert, Parker Geoff J M, Alexander Daniel C, Symms Mark R, Boulby Philip A, Wheeler-Kingshott Claudia A M, Barker Gareth J, Noppeney Uta, Koepp Matthias J, Duncan John S
Department of Clinical and Experimental Epilepsy, Institute of Neurology, University College London, Queen Square, London, WC1N 3BG, UK.
Neuroimage. 2006 Aug 1;32(1):388-99. doi: 10.1016/j.neuroimage.2006.03.011. Epub 2006 May 2.
Functional lateralization is a feature of human brain function, most apparent in the typical left-hemisphere specialization for language. A number of anatomical and imaging studies have examined whether structural asymmetries underlie this functional lateralization. We combined functional MRI (fMRI) and diffusion-weighted imaging (DWI) with tractography to study 10 healthy right-handed subjects. Three language fMRI paradigms were used to define language-related regions in inferior frontal and superior temporal regions. A probabilistic tractography technique was then employed to delineate the connections of these functionally defined regions. We demonstrated consistent connections between Broca's and Wernicke's areas along the superior longitudinal fasciculus bilaterally but more extensive fronto-temporal connectivity on the left than the right. Both tract volumes and mean fractional anisotropy (FA) were significantly greater on the left than the right. We also demonstrated a correlation between measures of structure and function, with subjects with more lateralized fMRI activation having a more highly lateralized mean FA of their connections. These structural asymmetries are in keeping with the lateralization of language function and indicate the major structural connections underlying this function.
功能偏侧化是人类大脑功能的一个特征，在典型的左半球语言特化中最为明显。许多解剖学和影像学研究探讨了结构不对称是否是这种功能偏侧化的基础。我们将功能磁共振成像（fMRI）和弥散加权成像（DWI）与纤维束成像相结合，对10名健康右利手受试者进行研究。使用三种语言fMRI范式来定义额下回和颞上回的语言相关区域。然后采用概率纤维束成像技术描绘这些功能定义区域的连接。我们证实了双侧沿上纵束的布洛卡区和韦尼克区之间存在一致的连接，但左侧额颞连接比右侧更广泛。左侧的纤维束体积和平均分数各向异性（FA）均显著大于右侧。我们还证明了结构和功能测量之间的相关性，即fMRI激活偏侧化程度更高的受试者，其连接的平均FA偏侧化程度也更高。这些结构不对称与语言功能的偏侧化一致，并表明了该功能的主要结构连接。
