Central and peripheral components in the control of speech movements.
| Number | 977 |
|---|---|
| Year | 1995 |
| Drawer | 18 |
| Entry Date | 07/01/1998 |
| Authors | Gracco, Vincent L. |
| Contact | |
| Publication | Bell-Berti, F. and Raphael, L.J. Producing Speech: Contemporary Issues. For Katerhine Safford Harris. AIP Press: New York. |
| url | http://www.haskins.yale.edu/Reprints/HL0977.pdf |
| Abstract | In the late 1950s and 1960s, much of the work at Haskins Laboratories focused on issues related to the representation of the phoneme - the presumed unit of speech. Attempts to find evidence for invariant signal properties in the acoustic stream representing the phoneme had been generally unsuccessful because of contextual variation, that is, coarticulation. As suggested by MacNeilage (1970) this led to two related positions regarding the nature of phonemic invariance. One position, posited by Lindblom (1963), Ladefoged (1967), and Steven and House (1963), was the invariance is in the vocal tract targets rather than in the peripheral manifestations at any observable level. The Haskins position was “that the EMG [electromyographic] correlates of the phoneme will prove to be invariant in some significant sense” (Liberman, Cooper, Harris, MacNeilage, & Studdert-Kenny, 1967, p. 84). The motivation for this search was that if there were phonemic units of speech, and the evidence from speech perception studies suggested that there were, they should be invariantly present in the muscular activity output. They reasoned that the acoustic signal was too far removed from the source of the invariance, since the invariance was a reflection of characteristics internal to the organism, in the central motor commands. Therefore, the best place to search fro invariance was in the peripheral manifestation of the central motor commands, which can be examined in the activity of muscles of the vocal tract using electromyography. |
| Notes |
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