Saur Dorothee, Kreher Björn W, Schnell Susanne, Kümmerer Dorothee, Kellmeyer Philipp, Vry Magnus-Sebastian, Umarova Roza, Musso Mariacristina, Glauche Volkmar, Abel Stefanie, Huber Walter, Rijntjes Michel, Hennig Jürgen, Weiller Cornelius
Department of Neurology, University Medical Center Freiburg, Breisacher Strasse 64, 79106 Freiburg, Germany.
Proc Natl Acad Sci U S A. 2008 Nov 18;105(46):18035-40. doi: 10.1073/pnas.0805234105. Epub 2008 Nov 12.
Built on an analogy between the visual and auditory systems, the following dual stream model for language processing was suggested recently: a dorsal stream is involved in mapping sound to articulation, and a ventral stream in mapping sound to meaning. The goal of the study presented here was to test the neuroanatomical basis of this model. Combining functional magnetic resonance imaging (fMRI) with a novel diffusion tensor imaging (DTI)-based tractography method we were able to identify the most probable anatomical pathways connecting brain regions activated during two prototypical language tasks. Sublexical repetition of speech is subserved by a dorsal pathway, connecting the superior temporal lobe and premotor cortices in the frontal lobe via the arcuate and superior longitudinal fascicle. In contrast, higher-level language comprehension is mediated by a ventral pathway connecting the middle temporal lobe and the ventrolateral prefrontal cortex via the extreme capsule. Thus, according to our findings, the function of the dorsal route, traditionally considered to be the major language pathway, is mainly restricted to sensory-motor mapping of sound to articulation, whereas linguistic processing of sound to meaning requires temporofrontal interaction transmitted via the ventral route.
基于视觉和听觉系统之间的类比，最近有人提出了以下语言处理双流模型：背侧流参与将声音映射到发音，腹侧流参与将声音映射到意义。本文所呈现的研究目的是检验该模型的神经解剖学基础。通过将功能磁共振成像（fMRI）与一种基于新颖扩散张量成像（DTI）的纤维束成像方法相结合，我们能够确定在两项典型语言任务中被激活的脑区之间最可能的解剖学通路。言语的亚词汇重复由一条背侧通路支撑，该通路通过弓状束和上纵束连接颞上叶和额叶的运动前区皮质。相比之下，高级语言理解由一条腹侧通路介导，该通路通过极端囊连接颞中叶和腹外侧前额叶皮质。因此，根据我们的研究结果，传统上被认为是主要语言通路的背侧通路的功能主要局限于声音到发音的感觉运动映射，而声音到意义的语言处理则需要通过腹侧通路传递的颞额叶相互作用。
