Development of force adaptation during childhood
Development of force adaptation during childhood
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DOI：
10.1080/00222890309602120
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发表时间：
2003-03-01
影响因子：
1.4
通讯作者：
Kalveram, KT
中科院分区：
文献类型：
--
作者：
Konczak, J;Jansen-Osmann, P;Kalveram, KT
人类通过获取肢体动力学的内部运动模型来学习在新的动态环境中进行伸展运动。在这里，作者调查了4至11岁的儿童（N = 39）和成人（N = 7）如何适应手臂动力学的变化，并研究了这些数据是否支持人类大脑在发育过程中获得逆动力学模型（IDM）的观点。当施加外部阻尼力时，孩子们学会了执行目标导向的前臂屈曲运动。在阻尼变化后，所有的儿童表现出运动学的后效，表明神经控制器仍然试图补偿不再存在的阻尼力。随着年龄的增长，完全适应的试验次数减少。当阻尼是存在的，前臂路径是最扰动和最小的孩子，但在年龄较大的儿童得到改善的变量。研究结果表明，肢体动力学的神经表征在儿童中不太精确，在时间上也不太稳定。这种控制器的不稳定性可能是儿童时期在许多运动任务中观察到的高运动变异性的主要原因。最后，年幼的孩子无法以与年长的孩子相同的速度更新这些模型，反过来，他们比成年人适应得更慢。总之，适应未知力量的能力是一种发展成就。目前的结果是一致的，认为收购和修改的内部模型的肢体动力学形成的基础上，自适应过程。
Humans learn to make reaching movements in novel dynamic environments by acquiring an internal motor model of their limb dynamics. Here, the authors investigated how 4- to 11-year-old children (N = 39) and adults (N = 7) adapted to changes in arm dynamics, and they examined whether those data support the view that the human brain acquires inverse dynamics models (IDM) during development. While external damping forces were applied, the children learned to perform goal-directed forearm flexion movements. After changes in damping, all children showed kinematic aftereffects indicative of a neural controller that still attempted to compensate the no longer existing damping force. With increasing age, the number of trials toward complete adaptation decreased. When damping was present, forearm paths were most perturbed and most variable in the youngest children but were improved in the older children. The findings indicate that the neural representations of limb dynamics are less precise in children and less stable in time than those of adults. Such controller instability might be a primary cause of the high kinematic variability observed in many motor tasks during childhood. Finally, the young children were not able to update those models at the same rate as the older children, who, in turn, adapted more slowly than adults. In conclusion, the ability to adapt to unknown forces is a developmental achievement. The present results are consistent with the view that the acquisition and modification of internal models of the limb dynamics form the basis of that adaptive process.