Acquisition and contextual switching of multiple internal models for different viscous force fields
Acquisition and contextual switching of multiple internal models for different viscous force fields
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DOI：
10.1016/s0168-0102(03)00094-4
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发表时间：
2003-07-01
影响因子：
2.9
通讯作者：
Kawato, M
中科院分区：
文献类型：
--
作者：
Wada, Y;Kawabata, Y;Kawato, M
人类可以在不同的环境中学习大量的运动行为。为了解释这一点，马赛克模型提出，大脑中获得了多个内部模型，这些模型可以切换。然而，之前的行为研究考察了手臂运动对多种环境的适应，报告称学习能力相当有限。到目前为止，人们一直认为人类无法学习两个相反的粘性力场，这两个力场都是动态变换，都依赖于相同的状态变量，以随机顺序呈现，只有一个视觉提示。相比之下，这项研究发现人类有能力做到这一点。肘关节对指定目标的运动受到单自由度机械手产生的阻力或辅助粘性力场的干扰。阻性或辅助性粘性力场分别由CRT屏幕上的蓝色或红色提示。以终点到目标的平方距离和关节角速度的方差作为运动学性能指标。随着训练天数的增加，这些运动误差显著减少。在两个力场的随机呈现中，后效和学习巩固被展示出来。因此，经过几天的训练，人类能够学习这两个力场的多个不同的内部模型，并适当地切换它们，即使是在只根据颜色提示的随机演示中也是如此。这项研究表明，以前提出的多内部模型学习的条件都不是必要条件，学习的难度是由上下文信息的有效性和力场的相似性之间的平衡决定的。(C)2003年爱思唯尔爱尔兰科学有限公司和日本神经科学学会。版权所有。
Humans can learn an enormous number of motor behaviors in different environments. To explain this, the MOSAIC model proposes that multiple internal models are acquired in the brain, which can be switched. However, previous behavioral studies that examined arm-movement adaptations to multiple environments reported a rather limited learning capability. Hitherto, humans have been believed incapable of learning two opposite viscous force fields, which are both dynamic transformations and depend on the same state variable, presented in a random order with only a visual cue. In contrast, this study found that humans are capable of this. Elbow joint movements to specified targets were perturbed by either resistive or assistive viscous force fields generated by a single degree-of-freedom manipulandum. The resistive or assistive viscous force fields were cued by a blue or red color on a CRT screen, respectively. The squared distance between the end point and the target, and the variance of the joint angular velocities were used as kinematic performance indices. These movement errors decreased significantly as a function of the training days. Aftereffects and learning consolidation were demonstrated in the random presentation of the two force fields. Consequently, humans were able to learn the multiple and distinct internal models of the two force fields and appropriately switch them even for a random presentation cued only by color after several days of training. This study suggests that none of the previously proposed conditions for multiple internal model learning are necessary prerequisites, and indicates that the difficulty in learning is determined by the balance between the effectiveness of contextual information and the similarity of force fields. (C) 2003 Elsevier Science Ireland Ltd and the Japan Neuroscience Society. All rights reserved.