Department of Biomedical Engineering, Washington University in Saint Louis, Saint Louis, MO 63130, USA.
J Neurophysiol. 2013 Sep;110(5):1246-56. doi: 10.1152/jn.00353.2012. Epub 2013 Jun 12.
Humans readily learn to move through direct physical practice and by watching the movements of others. Some researchers have proposed that action observation can inform subsequent changes in control through the acquisition of a neural representation of the novel dynamics, but to date learning following observation has been described by kinematic metrics. Here we designed an experiment to consider the specificity of adaptation to novel dynamic perturbations at the level of force generation. We measured changes in temporal patterns of force output following either the performance or observation of movements perturbed by either position- or velocity-dependent dynamic environments to 1) establish whether previously described observational motor learning effects were attributable to changes in predictive limb control and 2) determine whether such adaptation reflected a learned dependence on limb states appropriate to the haptic environment. We found that subjects who observed perturbed movements produced significant compensatory changes in their lateral force output, despite never directly experiencing force perturbations firsthand while performing the motor task. The time series of observers' adapted force outputs suggested that the state dependence of observed dynamics shapes adaptation. We conclude that the brain can transform observation of kinematics into state-dependent adaptation of reach dynamics.
人类可以通过直接的身体实践和观察他人的动作来轻松地学习运动。一些研究人员提出，通过获得对新动力学的神经表示，动作观察可以为后续的控制变化提供信息，但迄今为止，观察后的学习一直是通过运动学指标来描述的。在这里，我们设计了一个实验来考虑在力产生水平上对新动态干扰的适应的特异性。我们测量了在受到位置或速度相关动态环境干扰的运动的执行或观察之后，力输出的时间模式的变化，以确定先前描述的观察运动学习效应是否归因于对预测肢体控制的变化，以及是否这种适应反映了对适合触觉环境的肢体状态的习得依赖性。我们发现，尽管在执行运动任务时从未直接体验过力干扰，但观察到受干扰运动的受试者会在其侧向力输出中产生显著的补偿性变化。观察者适应的力输出的时间序列表明，观察到的动力学的状态依赖性塑造了适应。我们得出的结论是，大脑可以将运动学的观察转化为对接近动力学的状态依赖的适应。
