Role of Eye, Head, and Shoulder Geometry in the Planning of Accurate Arm Movements
1 Centre for Vision Research, 2 Canadian Institutes of Health Research Group for Action and Perception, 3 Department of Psychology, 4 Department of Biology, and 5 Department of Kinesiology and Health Sciences, York University, Toronto, Ontario M3J 1P3, Canada Henriques, D.Y.P. and J. D. Cr...
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Published in | Journal of neurophysiology Vol. 87; no. 4; pp. 1677 - 1685 |
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Main Authors | , |
Format | Journal Article |
Language | English |
Published |
United States
Am Phys Soc
01.04.2002
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Subjects | |
Online Access | Get full text |
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Summary: | 1 Centre for Vision Research,
2 Canadian Institutes of Health Research
Group for Action and Perception, 3 Department of
Psychology, 4 Department of Biology, and
5 Department of Kinesiology and Health Sciences,
York University, Toronto, Ontario M3J 1P3, Canada
Henriques, D.Y.P. and
J. D. Crawford.
Role of Eye, Head, and Shoulder Geometry in the Planning of
Accurate Arm Movements. J. Neurophysiol. 87: 1677-1685, 2002. 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. |
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Bibliography: | ObjectType-Article-2 SourceType-Scholarly Journals-1 ObjectType-Feature-1 content type line 23 ObjectType-Article-1 ObjectType-Feature-2 |
ISSN: | 0022-3077 1522-1598 |
DOI: | 10.1152/jn.00509.2001 |