MOTOR CORTEX FIELDS AND SPEECH MOVEMENTS - SIMPLE DUAL CONTROL IS IMPLAUSIBLE

We applaud the spirit of Macneilage's attempts to better explain the e volution and cortical control of speech by drawing on the vast literat ure in nonhuman primate neurobiology. However, he oversimplifies motor cortical fields and their known individual functions to such an exten t that he undermines the value of his effort. In particular, MacNeilag e has lumped together the functional characteristics across multiple m esial and lateral motor cortex fields, inadvertantly creating two hypo thetical centers that simply may not exist.