Date of Award


Degree Type


Degree Name

Doctor of Philosophy


This study deals with the following questions: (1) How precisely are movement properties matched for the two arms? (2) Is matching of movements of the two arms affected by visual information? (3) Are movements of one arm affected by kinesthetic information arising from the contralateral arm? (4) Does alteration in the motor performance of one arm affect movement performance in the other arm?;During experiments, subjects grasped a vertical rod attached to a horizontal manipulandum bar. The subject's shoulder was abducted to 90 deg. The manipulandum bar was pivoted above the subject's elbow. Subjects made step-tracking flexion/extension movements about the elbow. Both simultaneously and independently made movements of the two arms, performed at the subject's own speed, were studied.;During simultaneous arm movements, movements of the two arms were initiated at the same times. The degree of matching of movement parameters was dependent on visual information. In the absence of visual information, these parameters were exactly matched in simultaneous movements of the two arms. When visual information was provided by displaying the position of right or left arm to the subject, the movements of the "non-displayed" arm were consistently of greater amplitudes and velocities than those of the "displayed" arm. The relation between movement peak velocity and amplitude was linear for each arm and was the same (matched) for both arms under all visual conditions. This matching was also seen for the independently made movements.;In some experiments the left arm was loaded. Loading altered the slope of the peak velocity-amplitude relation in movements of the left arm. Similar changes occurred in the velocity-amplitude relation of the right (non-loaded) arm.;To test interlimb responses to kinesthetic information, high frequency (120 Hz) mechanical vibration of muscle tendons was used to stimulate muscle spindles of the elbow movers. Vibration of the triceps muscle of one arm produced overshooting of the intended flexion end-position by the opposite arm.;It is concluded that the motor actions of the two arms are functionally linked. Matching of movements made by the two arms may reflect the operation of a common motor program which can be modified by visual and kinesthetic information.



To view the content in your browser, please download Adobe Reader or, alternately,
you may Download the file to your hard drive.

NOTE: The latest versions of Adobe Reader do not support viewing PDF files within Firefox on Mac OS and if you are using a modern (Intel) Mac, there is no official plugin for viewing PDF files within the browser window.