Motor Coordination for Functional Human Behaviors: Perspectives From A Speech Motor Data Base

The term coordination , justifiably, is almost as common in discussions of motor systems as the word control In this vein, speech motor coordination provides a potential model system for examining this phenomenon. For speech and for most natural motor tasks, generating properly timed and measured multiple muscle contractions is a primary role of the motorsensory system. However, the understanding of the neurobiological processes underlying motor coordination has been hampered by several difficulties. First, single joint or oversimplified behaviors have been emphasized: it is dimcult to examine coordination if the number of elements being coordinated is unnaturally restricted. Second, many investigators have utilized superficial measures of behavior (keystrokes, speech acoustic signals, cursive writing patterns), thus largely ignoring the multiple underlying motor actions that are the crux of coordination. Finally, several lines of study, apparently aimed at coordination, have consisted largely of blanket searches for invariant patterns in certain aspects of system output-primarily without scientific hypotheses regarding biological processes. Fortunately, recent analyses of speech motor actions not only address some of these difficulties but also offer some more concrete data on underlying neurobiological mechanisms.