Journal article
Perception of arm orientation in three-dimensional space
Experimental brain research, Vol.102(3), pp.495-502
1995
DOI: 10.1007/BF00230653
PMID: 7737395
Abstract
The purpose of this investigation was to determine the preferred coordinate system for perception of arm (humerus) orientation in three-dimensional space. Perception of arm orientation relative to trunk fixed versus earth-fixed axes were compared in seven human subjects. The experimenter first moved the subject's trunk and arm into a target configuration (in which the arm's orientation relative to the trunk and/or earth was perceived and memorized by the subject) and then moved the trunk and arm to a new configuration. The blindfolded subject then attempted to reproduce the target orientation of their arm relative to either the trunk (i.e., reproduce shoulder angles intrinsic kinesthetic coordinate system) or earth-fixed axes (extrinsic kinesthetic coordinate system). Perceptual errors were similar for both shoulder (arm relative to trunk) and extrinsic (arm relative to earth) angles. However, elevation angles were perceived with greater accuracy than yaw angles in the two coordinate systems. Also, perceptual errors for arm yaw angles in the extrinsic kinesthetic coordinate system task were better predicted from changes in trunk orientation than the errors for other angles. Furthermore, four subjects matched arm yaw angle relative to the trunk-fixed axis more accurately than to the earth-fixed axis in the extrinsic coordinate system task. These results suggests a bias toward perception of yaw angles relative to trunk-fixed axes (i.e., in an intrinsic coordinate system). These data suggest that the preferred coordinate system for kinesthetic perception of arm orientation is probably fixed in the trunk. Sensory receptors in soft tissues surrounding the shoulder joint can provide sensations related directly to intrinsic (shoulder) angles, but not to angles of the arm in relation to external axes. However, elevation angles of the arm are perceived with about equal accuracy in relation to the trunk and the gravitational axis. Accurate perceptions of the angle of the arm with respect to gravity may be important for computations of the shoulder joint torques needed when producing upper limb movements. © 1995 Springer-Verlag.
Details
- Title: Subtitle
- Perception of arm orientation in three-dimensional space
- Creators
- W. G Darling - University of IowaG. F Miller - University of Iowa
- Resource Type
- Journal article
- Publication Details
- Experimental brain research, Vol.102(3), pp.495-502
- Publisher
- Springer
- DOI
- 10.1007/BF00230653
- PMID
- 7737395
- ISSN
- 0014-4819
- eISSN
- 1432-1106
- Language
- English
- Date published
- 1995
- Academic Unit
- Physical Therapy and Rehabilitation Science; Health and Human Physiology
- Record Identifier
- 9984259399202771
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