Patton James L, Mussa-Ivaldi Ferdinando A
Sensory Motor Performance Program, Rehabilitation Institute of Chicago, Physical Medicine and Rehabilitation, Mechanical & Biomedical Engineering, Northwestern University, 345 East Superior St., Room 1406, Chicago, IL 60611, USA.
IEEE Trans Biomed Eng. 2004 Apr;51(4):636-46. doi: 10.1109/TBME.2003.821035.
Based on recent studies of neuro-adaptive control, we tested a new iterative algorithm to generate custom training forces to "trick" subjects into altering their target-directed reaching movements to a prechosen movement as an after-effect of adaptation. The prechosen movement goal, a sinusoidal-shaped path from start to end point, was never explicitly conveyed to the subject. We hypothesized that the adaptation would cause an alteration in the feedforward command that would result in the prechosen movement. Our results showed that when forces were suddenly removed after a training period of 330 movements, trajectories were significantly shifted toward the prechosen movement. However, de-adaptation occurred (i.e., the after-effect "washed out") in the 50-75 movements that followed the removal of the training forces. A second experiment suppressed vision of hand location and found a detectable reduction in the washout of after-effects, suggesting that visual feedback of error critically influences learning. A final experiment demonstrated that after-effects were also present in the neighborhood of training--44% of original directional shift was seen in adjacent, unpracticed movement directions to targets that were 60 degrees different from the targets used for training. These results demonstrate the potential for these methods for teaching motor skills and for neuro-rehabilitation of brain-injured patients. This is a form of "implicit learning," because unlike explicit training methods, subjects learn movements with minimal instructions, no knowledge of, and little attention to the trajectory.
基于最近对神经自适应控制的研究，我们测试了一种新的迭代算法，以生成定制的训练力，从而“诱使”受试者改变其目标导向的伸手动作，使其作为适应的后效应而向预先选定的动作转变。预先选定的动作目标，即从起点到终点的正弦形路径，从未明确传达给受试者。我们假设这种适应会导致前馈指令发生改变，从而产生预先选定的动作。我们的结果表明，在进行330次动作的训练期后突然撤去力时，轨迹会显著向预先选定的动作方向偏移。然而，在撤去训练力后的50 - 75次动作中出现了去适应现象（即后效应“消失”）。第二个实验抑制了手部位置的视觉反馈，发现后效应的消退有明显减少，这表明误差的视觉反馈对学习有至关重要的影响。最后一个实验表明，在训练区域附近也存在后效应——在与训练所用目标相差60度的相邻未练习动作方向上，观察到了原始方向偏移的44%。这些结果证明了这些方法在教授运动技能和对脑损伤患者进行神经康复方面的潜力。这是一种“内隐学习”形式，因为与明确的训练方法不同，受试者在极少的指令、对轨迹没有了解且很少关注轨迹的情况下学习动作。
