Hinder Mark R, Woolley Daniel G, Tresilian James R, Riek Stephan, Carson Richard G
Perception and Motor Systems Laboratory, School of Human Movement Studies, University of Queensland, Brisbane 4072, Australia.
Exp Brain Res. 2008 Nov;191(2):143-55. doi: 10.1007/s00221-008-1513-7. Epub 2008 Aug 5.
We investigated visuomotor adaptation using an isometric, target-acquisition task. Following trials with no rotation, two participant groups were exposed to a random sequence of 30 degrees clockwise (CW) and 60 degrees counter-clockwise (CCW) rotations, with (DUAL-CUE), or without (DUAL-NO CUE), colour cues that enabled each environment (non-rotated, 30 degrees CW and 60 degrees CCW) to be identified. A further three groups experienced only 30 degrees CW trials or only 60 degrees CCW trials (SINGLE rotation groups) in which each visuomotor mapping was again associated with a colour cue. During training, all SINGLE groups reduced angular deviations of the cursor path during the initial portion of the movements, indicating feedforward adaptation. Consistent with the view that the adaptation occurred automatically via recalibration of the visuomotor mapping (Krakauer et al. 1999), post-training aftereffects were observed, despite colour cues that indicated that no rotation was present. For the DUAL-CUE group, angular deviations decreased with training in the 60 degrees trials, but were unchanged in the 30 degrees trials, while for the DUAL-NO CUE group angular deviations decreased for the 60 degrees CW trials but increased for the 30 degrees CW trials. These results suggest that in a dual adaptation paradigm a colour cue can permit delineation of the two environments, with a subsequent change in behaviour resulting in improved performance in at least one of these environments. Increased reaction times within the training block, together with the absence of aftereffects in the post-training period for the DUAL-CUE group suggest an explicit cue-dependent strategy was used in an attempt to compensate for the rotations.
我们使用等长目标获取任务来研究视觉运动适应。在进行无旋转的试验后，两个参与者组被暴露于30度顺时针（CW）和60度逆时针（CCW）旋转的随机序列中，一组有（双线索组），另一组没有（无双线索组）颜色线索，这些线索能够识别每个环境（非旋转、30度CW和60度CCW）。另外三组只经历30度CW试验或只经历60度CCW试验（单旋转组），其中每个视觉运动映射再次与一个颜色线索相关联。在训练过程中，所有单旋转组在运动初始阶段都减少了光标路径的角度偏差，表明存在前馈适应。与通过视觉运动映射重新校准自动发生适应的观点一致（Krakauer等人，1999年），尽管颜色线索表明没有旋转，但在训练后仍观察到了后效。对于双线索组，在60度试验中角度偏差随训练而减小，但在30度试验中保持不变，而对于无双线索组，60度CW试验中角度偏差减小，但30度CW试验中角度偏差增加。这些结果表明，在双重适应范式中，颜色线索可以区分两种环境，随后行为的改变会导致至少在其中一种环境中的表现得到改善。双线索组在训练块内反应时间增加，以及在训练后阶段没有后效，这表明使用了一种明确的依赖线索策略来试图补偿旋转。
