Abstract
It has been hypothesized that the end-point position of reaching may be specified in an egocentric frame of reference. In most previous studies, however, reaching was toward a memorized target, rather than an actual target. Thus, the role played by sensorimotor transformation could not be disassociated from the role played by storage in short-term memory. In the present study the direct process of sensorimotor transformation was investigated in reaching toward continuously visible targets that need not be stored in memory. A virtual reality system was used to present visual targets in different three-dimensional (3D) locations in two different tasks, one with visual feedback of the hand and arm position (Seen Hand) and the other without such feedback (Unseen Hand). In the Seen Hand task, the axes of maximum variability and of maximum contraction converge toward the mid-point between the eyes. In the Unseen Hand task only the maximum contraction correlates with the sight-line and the axes of maximum variability are not viewer-centered but rotate anti-clockwise around the body and the effector arm during the move from the right to the left workspace. The bulk of findings from these and previous experiments support the hypothesis of a two-stage process, with a gradual transformation from viewer-centered to body-centered and arm-centered coordinates. Retinal, extra-retinal and arm-related signals appear to be progressively combined in superior and inferior parietal areas, giving rise to egocentric representations of the end-point position of reaching.
| Original language | English |
|---|---|
| Pages (from-to) | 201-210 |
| Number of pages | 10 |
| Journal | Experimental Brain Research |
| Volume | 129 |
| Issue number | 2 |
| DOIs | |
| Publication status | Published - 1999 |
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Keywords
- Reaching
- Reference frame
- Spatial psychophysics
- Virtual reality
- Vision
ASJC Scopus subject areas
- Neuroscience(all)
Cite this
Viewer-centered and body-centered frames of reference in direct visuomotor transformations. / Carrozzo, M.; McIntyre, J.; Zago, M.; Lacquaniti, F.
In: Experimental Brain Research, Vol. 129, No. 2, 1999, p. 201-210.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Viewer-centered and body-centered frames of reference in direct visuomotor transformations
AU - Carrozzo, M.
AU - McIntyre, J.
AU - Zago, M.
AU - Lacquaniti, F.
PY - 1999
Y1 - 1999
N2 - It has been hypothesized that the end-point position of reaching may be specified in an egocentric frame of reference. In most previous studies, however, reaching was toward a memorized target, rather than an actual target. Thus, the role played by sensorimotor transformation could not be disassociated from the role played by storage in short-term memory. In the present study the direct process of sensorimotor transformation was investigated in reaching toward continuously visible targets that need not be stored in memory. A virtual reality system was used to present visual targets in different three-dimensional (3D) locations in two different tasks, one with visual feedback of the hand and arm position (Seen Hand) and the other without such feedback (Unseen Hand). In the Seen Hand task, the axes of maximum variability and of maximum contraction converge toward the mid-point between the eyes. In the Unseen Hand task only the maximum contraction correlates with the sight-line and the axes of maximum variability are not viewer-centered but rotate anti-clockwise around the body and the effector arm during the move from the right to the left workspace. The bulk of findings from these and previous experiments support the hypothesis of a two-stage process, with a gradual transformation from viewer-centered to body-centered and arm-centered coordinates. Retinal, extra-retinal and arm-related signals appear to be progressively combined in superior and inferior parietal areas, giving rise to egocentric representations of the end-point position of reaching.
AB - It has been hypothesized that the end-point position of reaching may be specified in an egocentric frame of reference. In most previous studies, however, reaching was toward a memorized target, rather than an actual target. Thus, the role played by sensorimotor transformation could not be disassociated from the role played by storage in short-term memory. In the present study the direct process of sensorimotor transformation was investigated in reaching toward continuously visible targets that need not be stored in memory. A virtual reality system was used to present visual targets in different three-dimensional (3D) locations in two different tasks, one with visual feedback of the hand and arm position (Seen Hand) and the other without such feedback (Unseen Hand). In the Seen Hand task, the axes of maximum variability and of maximum contraction converge toward the mid-point between the eyes. In the Unseen Hand task only the maximum contraction correlates with the sight-line and the axes of maximum variability are not viewer-centered but rotate anti-clockwise around the body and the effector arm during the move from the right to the left workspace. The bulk of findings from these and previous experiments support the hypothesis of a two-stage process, with a gradual transformation from viewer-centered to body-centered and arm-centered coordinates. Retinal, extra-retinal and arm-related signals appear to be progressively combined in superior and inferior parietal areas, giving rise to egocentric representations of the end-point position of reaching.
KW - Reaching
KW - Reference frame
KW - Spatial psychophysics
KW - Virtual reality
KW - Vision
UR - http://www.scopus.com/inward/record.url?scp=0032740798&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0032740798&partnerID=8YFLogxK
U2 - 10.1007/s002210050890
DO - 10.1007/s002210050890
M3 - Article
C2 - 10591894
AN - SCOPUS:0032740798
VL - 129
SP - 201
EP - 210
JO - Experimental Brain Research
JF - Experimental Brain Research
SN - 0014-4819
IS - 2
ER -