| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH |
|
|
|
|||||||
|
|||||||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
1 Biophysics, University of Nijmegen, Nijmegen, The Netherlands
* To whom correspondence should be addressed. E-mail: marjana{at}mbfys.kun.nl.
We examined the role of gaze in a task where subjects had to reproduce the position of a remembered visual target with the tip of the index finger, referred to as pointing. Subjects were tested in three visual feedback conditions: complete darkness (DARK), complete darkness with visual feedback of the finger position (FINGER), and with vision of a well-defined environment and feedback of the finger position (FRAME). Pointing accuracy increases with feedback about the finger or visual environment. In the FINGER and FRAME conditions, the 95% confidence regions of the variable errors have an ellipsoidal distribution with the main axis oriented towards the subjects' head. During the one-second period, when the target is visible, gaze is almost on target. However, gaze drifts away from the target relative to the subject in the delay period after target disappearance. In the FINGER and FRAME conditions, gaze returns towards the remembered target during pointing. In all three feedback conditions, the correlations between the variable errors of gaze and pointing position increase during the delay period, reaching highly significant values at the time of pointing. Our results demonstrate that gaze affects the accuracy of pointing. We conclude that the covariance between gaze and pointing position reflects a common drive for gaze and arm movements and an effect of gaze on pointing accuracy at the time of pointing. Previous studies interpreted the orientation of variable errors as indicative for a frame of reference used for pointing. Our results suggest that the orientation of the error ellipses towards the head is at least partly the result of gaze drift in the delay period.
This article has been cited by other articles:
|
|
 |
|
  C. Ghez, R. Scheidt, and H. Heijink Different Learned Coordinate Frames for Planning Trajectories and Final Positions in Reaching J Neurophysiol, December 1, 2007; 98(6): 3614 - 3626. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
E. J. Schlicht and P. R. Schrater Impact of Coordinate Transformation Uncertainty on Human Sensorimotor Control J Neurophysiol, June 1, 2007; 97(6): 4203 - 4214. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. Mapstone, D. Logan, and C. J. Duffy Cue integration for the perception and control of self-movement in ageing and Alzheimer's disease. Brain, November 1, 2006; 129(Pt 11): 2931 - 2944. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. M. Beurze, S. Van Pelt, and W. P. Medendorp Behavioral Reference Frames for Planning Human Reaching Movements J Neurophysiol, July 1, 2006; 96(1): 352 - 362. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
P. Vindras, M. Desmurget, and P. Viviani Error Parsing in Visuomotor Pointing Reveals Independent Processing of Amplitude and Direction J Neurophysiol, August 1, 2005; 94(2): 1212 - 1224. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. A. Admiraal, N.L.W. Keijsers, and C.C.A.M. Gielen Gaze Affects Pointing Toward Remembered Visual Targets After a Self-Initiated Step J Neurophysiol, October 1, 2004; 92(4): 2380 - 2393. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH |
| Visit Other APS Journals Online |
