美国哈佛大学Bence P. Ölveczky等研究人员合作发现，运动皮层在运动序列执行中的作用依赖于灵活性需求。相关论文于2024年11月4日在线发表在《自然—神经科学》杂志上。

研究人员探讨了运动皮层的参与程度是否依赖于任务需求，特别是其在高度练习的“自动”序列与受外部提示驱动的灵活序列中的作用是否不同。为了测试这一点，研究人员训练大鼠生成三元素运动序列，一组通过对单一序列进行过度训练，另一组则通过跟随视觉提示完成任务。

通过对运动皮层进行损伤，研究人员发现运动皮层对于灵活的提示驱动型运动序列是必需的，但对于单一自动行为（在隔离状态下训练）则不必要。然而，当一个自动运动序列与灵活任务一起练习时，它变得依赖于运动皮层，表明当同一个序列也在灵活背景下产生时，自动运动序列未能在皮层下整合。一个简单的神经网络模型重现了这些结果，并提供了一个回路层级的解释。

这些结果明确了运动皮层在运动序列执行中的作用，描述了它参与的条件和履行的功能，从而调和了关于运动皮层在运动序列生成中的作用的看似矛盾的观点。

据悉，运动皮层在执行运动序列中的作用被广泛争论，研究支持不同的观点。

附：英文原文

Title: The role of motor cortex in motor sequence execution depends on demands for flexibility

Author: Mizes, Kevin G. C., Lindsey, Jack, Escola, G. Sean, lveczky, Bence P.

Issue&Volume: 2024-11-04

Abstract: The role of the motor cortex in executing motor sequences is widely debated, with studies supporting disparate views. Here we probe the degree to which the motor cortex’s engagement depends on task demands, specifically whether its role differs for highly practiced, or ‘automatic’, sequences versus flexible sequences informed by external cues. To test this, we trained rats to generate three-element motor sequences either by overtraining them on a single sequence or by having them follow instructive visual cues. Lesioning motor cortex showed that it is necessary for flexible cue-driven motor sequences but dispensable for single automatic behaviors trained in isolation. However, when an automatic motor sequence was practiced alongside the flexible task, it became motor cortex dependent, suggesting that an automatic motor sequence fails to consolidate subcortically when the same sequence is produced also in a flexible context. A simple neural network model recapitulated these results and offered a circuit-level explanation. Our results critically delineate the role of the motor cortex in motor sequence execution, describing the conditions under which it is engaged and the functions it fulfills, thus reconciling seemingly conflicting views about motor cortex’s role in motor sequence generation.

DOI: 10.1038/s41593-024-01792-3

Source: https://www.nature.com/articles/s41593-024-01792-3