Cortical representation of sign language: Comparison of deaf signers and hearing non-signers

Numerous studies have demonstrated activation of the classical left-hemisph ere language areas when native signers process sign language. More recently , specific sign language-related processing has been suggested to occur in homologous areas of the right hemisphere as well. We now show that these co rtical areas are also activated in hearing non-signers during passive viewi ng of signs that for them are linguistically meaningless. Neuromagnetic act ivity was stronger in deaf signers than in hearing non-signers in the regio n of the right superior temporal sulcus and the left dorsal promotor cortex , probably reflecting familiarity and linguistic meaningfulness of the obse rved movement sequences. In contrast, the right superior parietal lobule, t he mesial parieto-occipital region, and the mesial paracentral lobule were more strongly activated in hearing non-signers, apparently reflecting activ e visuomotor encoding of complex unfamiliar movement sequences.