Cortical Encoding of Manual Articulatory and Linguistic Features in American Sign Language

The fluent production of a signed language requires exquisite coordination of sensory, motor, and cognitive processes. Similar to speech production, language produced with the hands by fluent signers appears effortless but reflects the precise coordination of both large-scale and local cortical networks. The organization and representational structure of sensorimotor features underlying sign language phonology in these networks remains unknown. Here, we present a unique case study of high-density electrocorticography (ECoG) recordings from the cortical surface of profoundly deaf signer during awake craniotomy. While neural activity was recorded from sensorimotor cortex, the participant produced a large variety of movements in linguistic and transitional movement contexts. We found that at both single electrode and neural population levels, high-gamma activity reflected tuning for particular hand, arm, and face movements, which were organized along dimensions that are relevant for phonology in sign language. Decoding of manual articulatory features revealed a clear functional organization and population dynamics for these highly practiced movements. Furthermore, neural activity clearly differentiated linguistic and transitional movements, demonstrating encoding of language-relevant articulatory features. These results provide a novel and unique view of the fine-scale dynamics of complex and meaningful sensorimotor actions. [Display omitted] •Sign language production requires coordinating sensorimotor and cognitive processes•We recorded electrocorticography (ECoG) while a deaf signer produced signs•Phonological sign features were distinctly represented in sensorimotor cortex•Population neural activity reflected linguistically relevant sensorimotor features Producing sign language requires coordination of phonologically organized hand movements. Leonard et al. record direct neural activity in a deaf signer undergoing brain surgery while he produces signs and other movements. Location and handshape are distinctly represented in sensorimotor cortex, revealing neural organization for sign articulation.