Viewer-centered and body-centered frames of reference in direct visuomotor transformations.

摘要: It has been hypothesized that the end-point position of reaching may be specified in an egocentric frame reference. In most previous studies, however, was toward a memorized target, rather than actual target. Thus, role played by sensorimotor transformation could not disassociated from storage short-term memory. present study direct process investigated continuously visible targets need stored A virtual reality system used to visual different three-dimensional (3D) locations two tasks, one with feedback hand and arm (Seen Hand) other without such (Unseen Hand). Seen Hand task, axes maximum variability contraction converge mid-point between eyes. Unseen task only correlates sight-line are viewer-centered but rotate anti-clockwise around body effector during move right left workspace. The bulk findings these experiments support hypothesis two-stage process, gradual body-centered arm-centered coordinates. Retinal, extra-retinal arm-related signals appear progressively combined superior inferior parietal areas, giving rise representations reaching.