| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
1Department of Biomedical Engineering, Marquette University, Milwaukee, Wisconsin; 2Department of Physical Medicine and Rehabilitation, Northwestern University Medical School, Chicago, Illinois; 3Sensory Motor Performance Program, Rehabilitation Institute of Chicago, Chicago, Illinois; 4Institute of Orthopaedic Research and Education, Houston, Texas; and 5Dipartimento di Informatica e Sistemistica, Universita' di Pavia, Pavia, Italy
Submitted 3 September 2004; accepted in final form 15 January 2005
People tend to make straight and smooth hand movements when reaching for an object. These trajectory features are resistant to perturbation, and both proprioceptive as well as visual feedback may guide the adaptive updating of motor commands enforcing this regularity. How is information from the two senses combined to generate a coherent internal representation of how the arm moves? Here we show that eliminating visual feedback of hand-path deviations from the straight-line reach (constraining visual feedback of motion within a virtual, "visual channel") prevents compensation of initial direction errors induced by perturbations. Because adaptive reduction in direction errors occurred with proprioception alone, proprioceptive and visual information are not combined in this reaching task using a fixed, linear weighting scheme as reported for static tasks not requiring arm motion. A computer model can explain these findings, assuming that proprioceptive estimates of initial limb posture are used to select motor commands for a desired reach and visual feedback of hand-path errors brings proprioceptive estimates into registration with a visuocentric representation of limb position relative to its target. Simulations demonstrate that initial configuration estimation errors lead to movement direction errors as observed experimentally. Registration improves movement accuracy when veridical visual feedback is provided but is not invoked when hand-path errors are eliminated. However, the visual channel did not exclude adjustment of terminal movement features maximizing hand-path smoothness. Thus visual and proprioceptive feedback may be combined in fundamentally different ways during trajectory control and final position regulation of reaching movements.
This article has been cited by other articles:
|
|
 |
|
  A. Reichenbach, A. Thielscher, A. Peer, H. H. Bülthoff, and J.-P. Bresciani Seeing the hand while reaching speeds up on-line responses to a sudden change in target position J. Physiol., October 1, 2009; 587(19): 4605 - 4616. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 R. A. Scheidt and C. Ghez Separate Adaptive Mechanisms for Controlling Trajectory and Final Position in Reaching J Neurophysiol, December 1, 2007; 98(6): 3600 - 3613. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
T. E. Hudson, L. T. Maloney, and M. S. Landy Movement Planning With Probabilistic Target Information J Neurophysiol, November 1, 2007; 98(5): 3034 - 3046. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. A. Scheidt and T. Stoeckmann Reach Adaptation and Final Position Control Amid Environmental Uncertainty After Stroke J Neurophysiol, April 1, 2007; 97(4): 2824 - 2836. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 T. D. Sanger, D. Chen, M. R. Delgado, D. Gaebler-Spira, M. Hallett, J. W. Mink, and the Taskforce on Childhood Motor Disorders Definition and Classification of Negative Motor Signs in Childhood Pediatrics, November 1, 2006; 118(5): 2159 - 2167. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
L. Ren, A. Z. Khan, G. Blohm, D.Y.P. Henriques, L. E. Sergio, and J. D. Crawford Proprioceptive Guidance of Saccades in Eye-Hand Coordination J Neurophysiol, September 1, 2006; 96(3): 1464 - 1477. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |
