Size of Error Affects Cerebellar Contributions to Motor Learning
Size of Error Affects Cerebellar Contributions to Motor Learning
复制标题
DOI：
10.1152/jn.00822.2009
复制
发表时间：
2010-04-01
影响因子：
2.5
通讯作者：
Shadmehr, Reza
中科院分区：
文献类型：
--
作者：
Criscimagna-Hemminger, Sarah E.;Bastian, Amy J.;Shadmehr, Reza
放大图片作者：John S.错误的大小影响小脑对运动学习的贡献。J Neurophysiol 103：2275-2284，2010.首次发表于2010年2月17日; doi：10.1152/jn.00822.2009。小错误可能会以与大错误完全不同的方式影响学习过程。例如，响应于小扰动而调整到达运动产生不同于大扰动的泛化模式。对大错误和小错误的反应是否有不同的神经机制？在这里，我们研究了严重小脑退化患者的运动学习过程。与早期的报告一致，我们发现，患者在适应他们的运动指令，在达到运动响应大，突然扰动深刻受损。然而，当在许多试验中逐渐施加相同幅度的干扰时，患者表现出明显的改善，揭示了从错误中学习的潜在能力。在突然移除扰动时，患者表现出的后遗症持续时间比健康对照组长得多。也就是说，尽管小脑受损，大脑仍保持着从小错误中学习的能力，而这种学习产生的运动记忆对变化有很强的抵抗力。值得注意的是，在完成学习后，小脑患者的运动输出在时间特征方面仍然与健康对照组不同。因此，小脑变性损害了从大幅度错误中学习的能力，但对从小错误中学习的影响较小。针对小错误和大错误的运动学习的神经基础似乎是不同的。
Criscimagna-Hemminger SE, Bastian AJ, Shadmehr R. Size of error affects cerebellar contributions to motor learning. J Neurophysiol 103: 2275-2284, 2010. First published February 17, 2010; doi: 10.1152/jn.00822.2009. Small errors may affect the process of learning in a fundamentally different way than large errors. For example, adapting reaching movements in response to a small perturbation produces generalization patterns that are different from large perturbations. Are distinct neural mechanisms engaged in response to large versus small errors? Here, we examined the motor learning process in patients with severe degeneration of the cerebellum. Consistent with earlier reports, we found that the patients were profoundly impaired in adapting their motor commands during reaching movements in response to large, sudden perturbations. However, when the same magnitude perturbation was imposed gradually over many trials, the patients showed marked improvements, uncovering a latent ability to learn from errors. On sudden removal of the perturbation, the patients exhibited aftereffects that persisted much longer than did those in healthy controls. That is, despite cerebellar damage, the brain maintained the ability to learn from small errors and the motor memory that resulted from this learning was strongly resistant to change. Of note was the fact that on completion of learning, the motor output of the cerebellar patients remained distinct from healthy controls in terms of its temporal characteristics. Therefore cerebellar degeneration impaired the ability to learn from large-magnitude errors, but had a lesser impact on learning from small errors. The neural basis of motor learning in response to small and large errors appears to be distinct.