• Cordo, Paul (PI)

Project: Research project

Project Details


This study proposes to investigate central nervous system control
strategies used to produce accurate movements. Control of voluntary
movement is viewed in this study as a stratified process with several
levels of control: 1) movements are initiated by high level construction
of open-loop motor commands, which are 2) executed form a reference frame
stabilized by a postural control system, and are 3) modified by sensory
feedback during both command execution ("concurrent feedback") and after
movement completion using knowledge of results ("delayed feedback").
Skilled movements and isometric force production are evaluated in terms of
these three control mechanisms.
Adult, human subjects will track various waveforms presented on a visual
display by exerting force on a manipulandum with their elbow musculature.
Comparison will be made of motor accuracy under a variety of conditions
affecting: 1) the predictability of the stimulus (tracking waveform)
amplitude, 2) the availability of visual feedback, 3) the degree of
postural stability, and 4) movement of the elbow joint. In most
experiments subjects will track step waveforms on an oscilloscope screen
while, in one experiment, designed to distinguish between strategies
subserving timing and metrical movement precision, graphical displays will
be more complex. Electromyographic activity will be recorded from
appropriate muscles during tracking experiments in order to characterize
movement strategies at a level of peripheral neural commands to muscles.
Amputees fitted with myoelectrically controlled arm prostheses will be used
in several phases of this study. In one experiment, these individuals will
be used as a model of the "deafferented arm" in order to characterize this
role of pehipheral somesthetic feedback in the control of accurate
movements in normal subjects. In addition, a pilot experiment is proposed
which directly addresses the problem of user control of multiple
degree-of-freedom powered arms. It is hoped that the latter experiment
will lead to the development of a large-scale research and training program
for amputees at Good Samaritan Hospital and Medical Center.
Effective start/end date12/1/8311/30/86


  • National Institutes of Health


  • Medicine(all)


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