Motion Analysis Laboratory, Kennedy Krieger Institute, Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA.
J Neurosci. 2010 Dec 15;30(50):17015-22. doi: 10.1523/JNEUROSCI.4205-10.2010.
Devices such as robots or treadmills are often used to drive motor learning because they can create novel physical environments. However, the learning (i.e., adaptation) acquired on these devices only partially generalizes to natural movements. What determines the specificity of motor learning, and can this be reliably made more general? Here we investigated the effect of visual cues on the specificity of split-belt walking adaptation. We systematically removed vision to eliminate the visual-proprioceptive mismatch that is a salient cue specific to treadmills: vision indicates that we are not moving while leg proprioception indicates that we are. We evaluated the adaptation of temporal and spatial features of gait (i.e., timing and location of foot landing), their transfer to walking over ground, and washout of adaptation when subjects returned to the treadmill. Removing vision during both training (i.e., on the treadmill) and testing (i.e., over ground) strongly improved the transfer of treadmill adaptation to natural walking. Removing vision only during training increased transfer of temporal adaptation, whereas removing vision only during testing increased the transfer of spatial adaptation. This dissociation reveals differences in adaptive mechanisms for temporal and spatial features of walking. Finally training without vision increased the amount that was learned and was linked to the variability in the behavior during adaptation. In conclusion, contextual cues can be manipulated to modulate the magnitude, transfer, and washout of device-induced learning in humans. These results bring us closer to our ultimate goal of developing rehabilitation strategies that improve movements beyond the clinical setting.
设备，如机器人或跑步机，通常用于驱动运动学习，因为它们可以创造新的物理环境。然而，在这些设备上获得的学习（即适应）仅部分地泛化到自然运动。什么决定了运动学习的特异性，并且可以可靠地使其更具通用性？在这里，我们研究了视觉提示对分割带行走适应特异性的影响。我们系统地去除了视觉，以消除跑步机特有的明显视觉-本体感觉失配：视觉表明我们没有移动，而腿部本体感觉表明我们在移动。我们评估了步态的时间和空间特征（即脚步落地的时间和位置）的适应，它们在地面行走中的转移，以及当受试者返回跑步机时适应的消退。在训练（即在跑步机上）和测试（即在地面上）期间去除视觉强烈改善了跑步机适应向自然行走的转移。仅在训练期间去除视觉会增加时间适应的转移，而仅在测试期间去除视觉会增加空间适应的转移。这种分离揭示了行走的时间和空间特征的适应性机制的差异。最后，没有视觉的训练增加了学习的量，并与适应过程中的行为变异性有关。总之，可以操纵上下文提示来调节设备诱导学习的幅度、转移和消退。这些结果使我们更接近我们的最终目标，即开发改善临床环境以外运动的康复策略。
