Journal Article

Functional organization of human sensorimotor cortex for speech articulation

Chang, Edward F., Mesgarani, Nima, Bouchard, Kristofer E., Johnson, Keith

2013

Overview

Speaking is one of the most complex actions that we perform, but nearly all of us learn to do it effortlessly. Production of fluent speech requires the precise, coordinated movement of multiple articulators (for example, the lips, jaw, tongue and larynx) over rapid time scales. Here we used 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 speech-articulator representations that are arranged somatotopically on ventral pre- and post-central gyri, and that partially overlap at individual electrodes. 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. Multi-electrode cortical recordings during the production of different consonant-vowel syllables reveal distinct speech-articulator representations that are arranged somatotopically, with temporal and spatial patterns of activity across the neural population corresponding to phonetic features and dynamics. Brain organization for speech The act of speaking requires precisely timed coordinated movement of the lips, jaw, tongue and larynx. Edward Chang and colleagues have explored the neural basis of this precise motor control. Multi-electrode recordings in human sensorimotor cortex reveal that the region of the brain involved in speech is laid out according to a somatotopic representation of the face and vocal tract, with large populations of cells corresponding to specific phonetic features. Of particular interest is an additional laryngeal representation located at the dorsal-most end of the ventral sensorimotor cortex, apparently absent in non-human primates, that may be a feature developed uniquely for the specialized control of speech.

• Publisher: Nature Publishing Group UK,Nature Publishing Group
• Subject: 631/378/2649/1594 / Biological and medical sciences / Cerebral Cortex - physiology / Electromagnetic Phenomena / Feedback, Sensory - physiology / Fundamental and applied biological sciences. Psychology / Humanities and Social Sciences / Humans / multidisciplinary / Phonetics / Principal Component Analysis / Science / Speech - physiology / Time Factors / Vertebrates: nervous system and sense organs