Motor planning center for speech articulation in the normal human brain

IN order to locate the coordination center of speech movements in the dominant hemisphere of the normal human brain, we measured magnetoencephalographic (MEG) signals from the left frontal area of right-handed subjects while they pronounced different words. A broad response appeared during a period of 120-320 ms before the onset of speech sound, and its current dipole sources were localized on the magnetic resonance images in a region around the superior end of the left insula. Further, the onset of the MEG response preceded by about 100 ms the perioral muscle activities that occurred for the articulation in speaking the words. These results suggest that the deep frontal region is involved in the articulatory programming of speech movements. NeuroReport 10:765-769 (C) 1999 Lippincott Williams & Wilkins.