ASA 127th Meeting M.I.T. 1994 June 6-10

1pSP34. Sagittal plane tongue-jaw coordination in speech.

K. G. Munhall

Dept. of Psychol., Queen's Univ., Kingston, ON K7L 3N6, Canada

D. J. Ostry

McGill Univ., Montreal, Quebec, Canada

In this presentation, the coordination of tongue and jaw movements in speech on the basis of two-dimensional x-ray microbeam recordings was examined. The goal is to specify the relationship between tongue motion and the motion of the jaw in each of its degrees of freedom. Specifically, the relationship between jaw position and orientation and the motion of x-ray tracking pellets on the tongue was examined. The relationship is studied both in the case in which the mechanical coupling of tongue and jaw motion is present and in the case where the contribution of jaw motion to tongue movements has been mathematically removed. Elsewhere, x-ray microbeam data have been presented that suggest that jaw position (i.e., translation) and orientation (i.e., rotation) in speech may be separately controlled [Ostry and Munhall, J. Neurophysiol. (in press)]. The present study extends this finding to address whether tongue and jaw motions in speech are coordinated on the basis of a linkage at the level of the system's degrees of freedom or whether the linkage occurs on some other basis. [Work supported by NSERC.]