Dorothee Saur1,2, Björn W. Kreher3,4, Susanne Schnell3,4, Dorothee Kümmerer2,4, Philipp Kellmeyer2,4, Magnus‐Sebastian Vry2,4, Roza M. Umarova2,4, Mariacristina Musso2,4, Volkmar Glauche2,4, Stefanie Abel5, Walter Huber5, Michel Rijntjes6,2, Jürgen Hennig3,4, Cornelius Weiller2,4
1Department of Neurology, University Medical Center Freiburg, Breisacher Strasse 64, 79106 Freiburg, Germany. [email protected] 2Departments of aNeurology and
3Department of Diagnostic Radiology, University Medical Center Freiburg, Freiburg, Germany
4Freiburg Brain Imaging, University Medical Center Freiburg, Breisacher Strasse 64, 79106 Freiburg, Germany; and
5Section of Neurolinguistics, Department of Neurology, RWTH Aachen University, Pauwelsstrasse 30, 52074 Aachen, Germany
6Department of Neurology, University Medical Center Freiburg, Freiburg, Germany
Tóm tắt
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.
