Functional organization of speech motor cortex

Edward Chang MD. Associate Professor in Residence of Neurological Surgery and Physiology, Keck Center for Integrative Neuroscience

Production of fluent speech requires the precise, coordinated movement of multiple articulators over rapid time scales. We describe the use of high-resolution, multi-electrode cortical recordings during the production of consonant-vowel syllables to determine the organization of speech sensorimotor cortex in humans. We found somatotopic arrangement of speech-articulator representations on ventral pre- and post-central gyri. These representations were coordinated temporally as sequences during syllable production. Spatial patterns of cortical activity showed an emergent, population-level representation, which was organized by phonetic features. Over tens of milliseconds, the spatial patterns transitioned between distinct representations for different consonants and vowels. These results reveal the dynamic organization of speech sensorimotor cortex during the generation of multi-articulator movements that underlies our ability to speak.