The Brain and Mind Institute, Western University , London, Ontario , Canada.
Department of Computer Science, Western University , London, Ontario , Canada.
J Neurophysiol. 2019 Jun 1;121(6):2088-2100. doi: 10.1152/jn.00041.2019. Epub 2019 Apr 10.
The ability to perform complex sequences of movements quickly and accurately is critical for many motor skills. Although training improves performance in a large variety of motor sequence tasks, the precise mechanisms behind such improvements are poorly understood. Here we investigated the contribution of single-action selection, sequence preplanning, online planning, and motor execution to performance in a discrete sequence production task. Five visually presented numbers cued a sequence of five finger presses, which had to be executed as quickly and accurately as possible. To study how sequence planning influenced sequence production, we manipulated the amount of time that participants were given to prepare each sequence by using a forced-response paradigm. Over 4 days, participants were trained on 10 sequences and tested on 80 novel sequences. Our results revealed that participants became faster in selecting individual finger presses. They also preplanned three or four sequence items into the future, and the speed of preplanning improved for trained, but not for untrained, sequences. Because preplanning capacity remained limited, the remaining sequence elements had to be planned online during sequence execution, a process that also improved with sequence-specific training. Overall, our results support the view that motor sequence learning effects are best characterized by improvements in planning processes that occur both before and concurrently with motor execution. Complex skills often require the production of sequential movements. Although practice improves performance, it remains unclear how these improvements are achieved. Our findings show that learning effects in a sequence production task can be attributed to an enhanced ability to plan upcoming movements. These results shed new light on planning processes in the context of movement sequences and have important implications for our understanding of the neural mechanisms that underlie skill acquisition.
快速而准确地执行复杂动作序列的能力对于许多运动技能至关重要。尽管训练可以提高各种运动序列任务的表现，但对于这种提高背后的精确机制仍知之甚少。在这里，我们研究了单项动作选择、序列预规划、在线规划和运动执行对离散序列产生任务表现的贡献。五个视觉呈现的数字提示了一个由五个手指按压组成的序列，参与者必须尽快且尽可能准确地执行该序列。为了研究序列规划如何影响序列产生，我们使用强制反应范式来控制参与者准备每个序列的时间量，从而研究序列规划如何影响序列产生。在 4 天的时间里，参与者接受了 10 个序列的训练，并接受了 80 个新序列的测试。我们的研究结果表明，参与者在选择单个手指按压时变得更快。他们还提前三到四个序列项进行预规划，并且预规划速度对于受过训练的序列而不是未受过训练的序列有所提高。由于预规划能力仍然有限，剩余的序列元素必须在序列执行过程中在线规划，这个过程也随着特定于序列的训练而提高。总的来说，我们的研究结果支持这样一种观点，即运动序列学习效果最好的特征是在运动执行之前和同时发生的规划过程的改进。 复杂技能通常需要产生序列运动。尽管练习可以提高表现，但仍不清楚这些提高是如何实现的。我们的发现表明，在序列产生任务中的学习效果可以归因于增强了规划即将到来的运动的能力。这些结果为运动序列中的规划过程提供了新的视角，并对我们理解技能习得背后的神经机制具有重要意义。
