Abstract

Theoretical linguistics stipulates that the core combinatorial system that builds hierarchical syntactic structure is modality-independent. Two recent studies with deaf native signers tested this claim neurobiologically using functional MRI and diffusion-weighted MRI: The functional MRI study showed that deaf signers recruit the same left posterior inferior frontal and posterior temporal regions for compositional processes which have previously been associated with syntactic processing in hearing users of a spoken language. The diffusion MRI study examined language-relevant white-matter pathways and found no group differences in the left arcuate fasciculus which interconnects these core language regions. Group differences emerged only in right-hemispheric pathways implicated in visuospatial processing. Together, these findings suggest that the adult human brain implements a primarily left-hemispheric fronto-temporal syntactic‑combinatorial network that is independent of the modality of language use.