The Role of Human Primary Motor Cortex in the Production of Skilled Finger Sequences
The Role of Human Primary Motor Cortex in the Production of Skilled Finger Sequences
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DOI：
10.1523/jneurosci.2798-17.2017
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发表时间：
2018-02
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影响因子：
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通讯作者：
Atsushi Yokoi;Spencer A. Arbuckle;J. Diedrichsen
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作者：
Atsushi Yokoi;Spencer A. Arbuckle;J. Diedrichsen
人类初级运动皮层（M1）是产生灵巧手运动所必需的。虽然不同的神经元亚群在单指运动过程中被激活，但仍不清楚M1是否也代表多指运动的序列。利用新的多变量功能磁共振成像（fMRI）分析技术，并结合证据从3T和7T fMRI数据，我们发现，经过5天的激烈的练习，运动前区和顶叶区编码不同的运动序列。有很少或没有证据表明，在M1的序列表示。相反，M1中的活动模式可以完全由构成个体手指运动的模式的线性组合来解释，其中序列的第一个手指上的权重最大。使用被动重放的序列，我们表明，这第一指效应是由于参与主动执行的神经元过程，而不是血液动力学的非线性。这些结果表明，在序列开始时，M1从具有序列表示的区域接收到更多的输入，但M1活动本身仅与手指按压组件的执行有关。这些结果提高了我们对短期训练后手指序列在人类新皮层中的代表性的理解，并为长期技能发展的研究提供了重要的方法学进展。有明确的证据表明，人类初级运动皮层（M1）对于产生个性化的手指运动（如按下按钮）至关重要。除了参与动作执行之外，尚不清楚M1是否还在学习和控制多个手指动作的序列中发挥作用，例如在弹钢琴时。使用先进的多变量功能磁共振成像分析和精心控制的实验，我们在这里证明，虽然运动前区清楚地显示了序列表示，在M1的活动模式可以完全解释从个人手指运动的模式。这些结果为M1和前运动皮层的相互作用提供了重要的新见解，以学习顺序运动。
Human primary motor cortex (M1) is essential for producing dexterous hand movements. Although distinct subpopulations of neurons are activated during single-finger movements, it remains unknown whether M1 also represents sequences of multiple finger movements. Using novel multivariate functional magnetic resonance imaging (fMRI) analysis techniques and combining evidence from both 3T and 7T fMRI data, we found that after 5 d of intense practice, premotor and parietal areas encoded the different movement sequences. There was little or no evidence for a sequence representation in M1. Instead, activity patterns in M1 could be fully explained by a linear combination of patterns for the constituent individual finger movements, with the strongest weight on the first finger of the sequence. Using passive replay of sequences, we show that this first-finger effect is due to neuronal processes involved in the active execution, rather than to a hemodynamic nonlinearity. These results suggest that M1 receives increased input from areas with sequence representations at the initiation of a sequence, but that M1 activity itself relates to the execution of component finger presses only. These results improve our understanding of the representation of finger sequences in the human neocortex after short-term training and provide important methodological advances for the study of long-term skill development. SIGNIFICANCE STATEMENT There is clear evidence that human primary motor cortex (M1) is essential for producing individuated finger movements, such as pressing a button. Over and above its involvement in movement execution, it is less clear whether M1 also plays a role in learning and controlling sequences of multiple finger movements, such as when playing the piano. Using cutting-edge multivariate fMRI analysis and carefully controlled experiments, we demonstrate here that, while premotor areas clearly show a sequence representation, activity patterns in M1 can be fully explained from the patterns for individual finger movements. The results provide important new insights into the interplay of M1 and premotor cortex for learning of sequential movements.