 |
| Research article summary (published 30 Mar 2002): |
|
Free Full Text! See links below |
Role of eye, head, and shoulder geometry in the planning of accurate arm movements.
Full Abstract
Eye-hand coordination requires the brain to integrate visual information with the continuous changes in eye, head, and arm positions. This is a geometrically complex process because the eyes, head, and shoulder have different centers of rotation. As a result, head rotation causes the eye to translate with respect to the shoulder. The present study examines the consequences of this geometry for planning accurate arm movements in a pointing task with the head at different orientations. When asked to point at an object, subjects oriented their arm to position the fingertip on the line running from the target to the viewing eye. But this eye-target line shifts when the eyes translate with each new head orientation, thereby requiring a new arm pointing direction. We confirmed that subjects do realign their fingertip with the eye-target line during closed-loop pointing across various horizontal head orientations when gaze is on target. More importantly, subjects also showed this head-position-dependent pattern of pointing responses for the same paradigm performed in complete darkness. However, when gaze was not on target, compensation for these translations in the rotational centers partially broke down. As a result, subjects tended to overshoot the target direction relative to current gaze; perhaps explaining previously reported errors in aiming the arm to retinally peripheral targets. These results suggest that knowledge of head position signals and the resulting relative displacements in the centers of rotation of the eye and shoulder are incorporated using open-loop mechanisms for eye-hand coordination, but these translations are best calibrated for foveated, gaze-on-target movements.
Learn Faster Today Improve your study skills
Author information
Author/s: Henriques, D Y P (DY); Crawford, J D (JD);
Affiliation: Centre for Vision Research, York University, Toronto, Ontario M3J 1P3, Canada.
Journal and publication information
Publication Type: Journal Article; Research Support, Non-U.S. Gov't
Journal: Journal of neurophysiology (J Neurophysiol), published in United States. (Language: eng)
Reference: 2002-Apr; vol 87 (issue 4) : pp 1677-85
Dates: Created 2002/04/03; Completed 2002/06/12; Revised 2006/11/15;
PMID: 11929889, 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.
External Links for this article (including full text providers, if available):
Click Electronic Full-text Provider Links to see options for finding the electronic full text links to this article. Note there may be a subscription or fee required for access to the full text. See our FAQ for information on finding FREE full text articles.
This article may also be located in paper journal collections available in many libraries. Use the Journal and Publication Information above to find the full article.
MeSH headings (categories)
This article was linked to the MESH Headings shown below.
|
|
Related articles
This article has not been indexed for related articles as yet, however you can still use the live related article search links below.
See a large map of 100+ related articles.