Objective: Motor variability - performance variations across task repetitions - has been assumed to be undesirable. But recent studies argue that variability facilitates early motor learning by allowing exploratory search of reward-generating motion, and that variability's structure may be modulated by neural circuits for furthering learning. What are the neural sources of learning-relevant motor variability and its modulation in humans of different ages? Methods: Elderlies and young adults played a 3-session virtual bowling while multi-muscle electromyographic signals were collected. We quantified trial-to-trial variability of muscle synergies - neuromotor control modules - and of their activations. Results: In elderlies, bowling-score gain correlated with change of activation timing variability of specific synergies, but in young adults, with variability changes of synergy-activation magnitude, and of the synergies themselves. Conclusions: Variability modulation of specific muscle synergies and their activations contribute to early motor learning. Elderly and young individuals may rely on different aspects of motor variability to drive learning.

中文翻译：

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通过老年人和年轻人的特定肌肉协同作用调节技能学习的运动变异性结构

目的：运动变异性——任务重复中的表现变化——被认为是不可取的。但最近的研究认为，可变性通过允许对产生奖励的运动进行探索性搜索来促进早期运动学习，并且可变性的结构可能会受到神经回路的调节以促进学习。与学习相关的运动变异性及其在不同年龄的人类中的调节的神经来源是什么？方法：长者和青壮年打3节虚拟保龄球，同时采集多肌肉肌电信号。我们量化了肌肉协同作用（神经运动控制模块）及其激活的试验间变异性。结果：在老年人中，保龄球得分的增加与特定协同作用的激活时间变异性的变化相关，但在年轻人中，随着协同作用激活幅度和协同作用本身的可变性变化。结论：特定肌肉协同作用的可变性调节及其激活有助于早期运动学习。老年人和年轻人可能依赖运动变异性的不同方面来推动学习。