Task-specific sensorimotor adaptation to reversing prisms.
We tested between three levels of visuospatial adaptation (global map, parallel feature modules, and parallel sensorimotor transformations) by training subjects to reach and grasp virtual objects viewed through a left-right reversing prism, with either visual location or orientation feedback. Even though spatial information about the global left-right reversal was present in every training session, subjects trained with location feedback reached to the correct location but with the wrong (reversed) grasp orientation. Subjects trained with orientation feedback showed the opposite pattern. These errors were task-specific and not feature-specific; subjects trained to correctly grasp visually reversed-oriented bars failed to show knowledge of the reversal when asked to point to the end locations of these bars. These results show that adaptation to visuospatial distortion--even global reversals--is implemented through learning rules that operate on parallel sensorimotor transformations (e.g., reach vs. grasp).
Marotta
Jonathan J
JJ
York Centre for Vision Research and Canadian Institutes of Health Research Group for Action and Perception, Department of Psychology, York University, Toronto, Ontario, Canada. marotta@cc.umanitoba.ca
Keith
Gerald P
GP
Crawford
J Douglas
JD
D000222:Adaptation, Physiological / Q000502:physiology*; D006801:Humans; D009949:Orientation / Q000502:physiology*; D010775:Photic Stimulation / Q000379:methods*; D011597:Psychomotor Performance / Q000502:physiology*