| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH |
|
|
|
|||||||
|
|||||||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
1 Nijmegen Institute for Cognition and Information, Radboud University Nijmegen, Nijmegen, Netherlands; FC Donders Centre for Cognitive Neuroimaging, Radboud University Nijmegen, Nijmegen, Netherlands
* To whom correspondence should be addressed. E-mail: s.beurze{at}nici.ru.nl.
At some stage in the process of a sensorimotor transformation for a reaching movement, information about the current position of the hand and information about the location of the target must be encoded in the same frame of reference in order to compute the hand-to-target difference vector. Two main hypotheses have been proposed regarding this reference frame: an eye-centered frame and a body-centered frame. Here we evaluated these hypotheses using the pointing errors that subjects made when planning and executing arm movements to memorized targets starting from various initial hand positions while keeping gaze fixed in various directions. One group of subjects (n=10) was tested without visual information about hand position during movement planning (Unseen Hand condition); another group (n=8) was tested with hand and target position simultaneously visible before movement onset (Seen Hand condition). We found that both initial hand position and gaze fixation direction had a significant effect on the magnitude and direction of the pointing error. Errors were significantly smaller in the Seen Hand condition. For both conditions, though, a reference frame analysis showed that the errors arose either at an eye-centered stage, or at a hand-centered stage, or both, but not at a body-centered stage. As a common reference frame is required to specify a movement vector, these results suggest that an eye-centered mechanism is involved in integrating target and hand position in programming reaching movements. We discuss how simple gain elements modulating the eye-centered target and hand position signals can account for these results.
This article has been cited by other articles:
|
|
 |
|
  T. R. Makin, N. P. Holmes, C. Brozzoli, Y. Rossetti, and A. Farne Coding of Visual Space during Motor Preparation: Approaching Objects Rapidly Modulate Corticospinal Excitability in Hand-Centered Coordinates J. Neurosci., September 23, 2009; 29(38): 11841 - 11851. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. M. Beurze, F. P. de Lange, I. Toni, and W. P. Medendorp Spatial and Effector Processing in the Human Parietofrontal Network for Reaches and Saccades J Neurophysiol, June 1, 2009; 101(6): 3053 - 3062. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
P. Bedard and J. N. Sanes Gaze and Hand Position Effects on Finger-Movement-Related Human Brain Activation J Neurophysiol, February 1, 2009; 101(2): 834 - 842. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. A. Thompson and D. Y. P. Henriques Updating Visual Memory Across Eye Movements for Ocular and Arm Motor Control J Neurophysiol, November 1, 2008; 100(5): 2507 - 2514. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. R. Flanagan, Y. Terao, and R. S. Johansson Gaze Behavior When Reaching to Remembered Targets J Neurophysiol, September 1, 2008; 100(3): 1533 - 1543. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
G. U. Sorrento and D. Y. P. Henriques Reference Frame Conversions for Repeated Arm Movements J Neurophysiol, June 1, 2008; 99(6): 2968 - 2984. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. Van Pelt and W. P. Medendorp Updating Target Distance Across Eye Movements in Depth J Neurophysiol, May 1, 2008; 99(5): 2281 - 2290. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. Van Pelt and W. P. Medendorp Gaze-Centered Updating of Remembered Visual Space During Active Whole-Body Translations J Neurophysiol, February 1, 2007; 97(2): 1209 - 1220. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. M. Beurze, F. P. de Lange, I. Toni, and W. P. Medendorp Integration of Target and Effector Information in the Human Brain During Reach Planning J Neurophysiol, January 1, 2007; 97(1): 188 - 199. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH |
| Visit Other APS Journals Online |
