Involvement of classical anterior and posterior language areas in sign language production, as investigated by 4 T functional magnetic resonance imaging

Abstract

To investigate the cerebral organization for language production across the particular channels supporting linguistic behavior, a functional magnetic resonance (fMRI) study was conducted in deaf native users of American Sign Language (ASL) and age-matched hearing controls. Seven native ASL speakers and 15 vocal English speaking subjects covertly performed an object naming task inside the 4 T scanner using their native languages ASL or English, respectively. In subjects of both groups, classical language areas were found to be activated, including posterior Broca's area, the anterior insula, premotor cortex, and the posterior parts of the superior temporal cortex. Activations showed a predominance of the left hemisphere for both groups. In the deaf group, however, there was markedly larger involvement of the cerebellum, the inferior frontal gyrus, and the posterior insula and more robust activation in occipito-temporal and superior parietal cortices. In summary, it could be demonstrated by fMRI that native language production using ASL is associated with activation of classical language areas, although the neural organization for language processing is not identical in the two language modalities ASL and English language.