ABSTRACT
Studies of primate premotor cortex, and, in particular, of the so-called mirror system, including humans, suggest the existence of a double hand/mouth motor command system involved in ingestion activities. This may be the platform on which a combined manual and vocal communication system was constructed. In support of this view, we will present behavioral and TMS data showing that the execution/observation of hand transitive actions, such as grasping and bringing-to-the-mouth, influences mouth movements and production of phonological units (i.e. syllables). Conversely, mouth postures and vocalization influence the control of transitive actions. This hand/mouth motor command system is found to play an important role in the development of speech in infants. Finally, we suggest that this system evolved a system controlling words and symbolic gestures: we propose that this system is located in Broca’s area.
