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| Research article summary (published 30 Dec 2001): |
Visuomotor transformations for eye-hand coordination.
Full Abstract
In recent years the scientific community has come to appreciate that the early cortical representations for visually guided arm movements are probably coded in a visual frame, i.e. relative to retinal landmarks. While this scheme accounts for many behavioral and neurophysiological observations, it also poses certain problems for manual control. For example, how are these oculocentric representations updated across eye movements, and how are they then transformed into useful commands for accurate movements of the arm relative to the body? Also, since we have two eyes, which is used as the reference point in eye-hand alignment tasks like pointing? We show that patterns of errors in human pointing suggest that early oculocentric representations for arm movement are remapped relative to the gaze direction during each saccade. To then transform these oculocentric representations into useful commands for accurate movements of the arm relative to the body, the brain correctly incorporates the three-dimensional, rotary geometry of the eyes when interpreting retinal images. We also explore the possibility that the eye-hand coordination system uses a strategy like ocular dominance, but switches alignment between the left and right eye in order to maximize eye-hand coordination in the best field of view. Finally, we describe the influence of eye position on eye-hand alignment, and then consider how head orientation influences the linkage between oculocentric visual frames and bodycentric motor frames. These findings are framed in terms of our 'conversion-on-demand' model, which suggests a virtual representation of egocentric space, i.e. one in which only those representations selected for action are put through the complex visuomotor transformations required for interaction with actual objects in personal space.
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Author information
Author/s: Henriques, D Y P (DY); Medendorp, W P (WP); Khan, A Z (AZ); Crawford, J D (JD);
Affiliation: York University, Centre for Visual Research, Departments of Psychology and Biology, 4700 Keele St., BSB, rm 291, Toronto, ON M3J 1P3, Canada.
Journal and publication information
Publication Type: Journal Article; Research Support, Non-U.S. Gov't; Review
Journal: Progress in brain research (Prog Brain Res), published in Netherlands. (Language: eng)
Reference: 2002-; vol 140 (issue ) : pp 329-40
Dates: Created 2003/01/01; Completed 2003/01/27; Revised 2006/11/15;
PMID: 12508600, status: MEDLINE (last retrieval date: 11/6/2008)
Sourced from the National Library of Medicine. Abstract text and other information may be subject to copyright.
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