Centre for Cognitive Science, Indian Institute of Technology Gandhinagar, Gujarat, India.
Department of Mechanical Engineering, Indian Institute of Technology Gandhinagar, Gujarat, India.
J Neurophysiol. 2018 Sep 1;120(3):1061-1073. doi: 10.1152/jn.00905.2017. Epub 2018 May 23.
Learning from motor errors that occur across different limbs is essential for effective tool use, sports training, and rehabilitation. To probe the neural organization of error-driven learning across limbs, we asked whether learning opposing visuomotor mappings with the two arms would interfere. Young right-handers first adapted to opposite visuomotor rotations A and B with different arms and were then reexposed to A 24 h later. We observed that relearning of A was never faster nor were initial errors smaller than prior A learning, which would be expected if there was no interference from B. Rather, errors were greater than or similar to, and learning rate was slower than or comparable to, previous A learning depending on the order in which the arms learned. This indicated robust interference between the motor memories of A and B when they were learned with different arms in close succession. We then proceeded to uncover that the order-dependent asymmetry in performance upon reexposure resulted from asymmetric transfer of learning from the left arm to the right but not vice versa and that the observed interference was retrograde in nature. Such retrograde interference likely occurs because the two arms require the same neural resources for learning, a suggestion consistent with that of our past work showing impaired learning following left inferior parietal damage regardless of the arm used. These results thus point to a common neural basis for formation of new motor memories with different limbs and hold significant implications for how newly formed motor memories interact. NEW & NOTEWORTHY In a series of experiments, we demonstrate robust retrograde interference between competing motor memories developed through error-based learning with different arms. These results provide evidence for shared neural resources for the acquisition of motor memories across different limbs and also suggest that practice with two effectors in close succession may not be a sound approach in either sports or rehabilitation. Such training may not allow newly acquired motor memories to be stabilized.
从不同肢体中出现的运动错误中学习对于有效的工具使用、运动训练和康复至关重要。为了探究跨肢体的错误驱动学习的神经组织，我们研究了使用双臂学习相反的视动映射是否会产生干扰。年轻的右利手者首先用不同的手臂适应相反的视动旋转 A 和 B，然后在 24 小时后重新暴露于 A。我们观察到，A 的重新学习速度从未更快，初始错误也从未小于之前的 A 学习，这表明 B 没有干扰。相反，错误比以前的 A 学习更大或相似，学习速度比以前的 A 学习更慢或相当，这取决于手臂学习的顺序。这表明当双臂在紧密的连续顺序中学习时，A 和 B 的运动记忆之间存在强烈的干扰。然后，我们发现重新暴露时的性能出现依赖于顺序的不对称性，这是由于从左到右的学习不对称转移造成的，而不是相反，并且观察到的干扰是逆行的。这种逆行干扰可能是因为两个手臂在学习时需要相同的神经资源，这一建议与我们过去的工作一致，即无论使用哪只手臂，左顶下叶损伤后都会导致学习能力受损。因此，这些结果指向了使用不同肢体形成新运动记忆的共同神经基础，并对新形成的运动记忆如何相互作用具有重要意义。新的和值得注意的是，在一系列实验中，我们证明了通过使用不同的手臂进行基于错误的学习而形成的竞争运动记忆之间存在强烈的逆行干扰。这些结果为不同肢体的运动记忆获取共享神经资源提供了证据，也表明在运动或康复中，两个效应器的紧密连续练习可能不是一个明智的方法。这种训练可能不允许新获得的运动记忆稳定下来。
