Neural Substrates of Muscle Co-contraction during Dynamic Motor Adaptation
Neural Substrates of Muscle Co-contraction during Dynamic Motor Adaptation
复制标题
DOI：
10.1523/jneurosci.2924-19.2021
复制
发表时间：
2021-06-30
影响因子：
5.3
通讯作者：
Milner, Theodore E.
中科院分区：
文献类型：
--
作者：
Babadi, Saeed;Vandat, Shahabeddin;Milner, Theodore E.
当我们学习用新的动力学来执行运动任务时，中枢神经系统必须适应运动命令并修改感觉运动转换。目前的研究的目的是确定适应过程的神经机制。先前已经表明，肌肉共收缩的增加通常与适应的初始阶段相关联，并且随着性能的提高，共收缩逐渐减少。我们的调查集中在肌肉共同收缩的神经基板在运动适应过程中使用静息状态的功能磁共振成像方法在健康的人类受试者的性别。我们分析了在适应的三个阶段，对应于不同的肌肉共同收缩水平的静息状态网络的功能连接，并发现在一个大脑网络的功能连接的强度的变化与共同收缩的度量，并在另一个与运动学习的度量。我们确定小脑是调节肌肉共同收缩的关键组成部分，特别是它与顶下小叶的连接，这在早期适应中特别突出。小脑，上级额回和运动皮质区域之间的神经联系与适应后期共同收缩的减少有关。我们还发现了涉及初级运动皮层的网络功能连接的可靠变化，结果表明，小脑和顶叶上级小叶与运动学习密切相关。收缩肌肉是通过调节机械阻抗提供姿势稳定性的有效策略，从而允许中枢神经系统补偿不熟悉或意外的身体状况，可以适当地调整命令。本研究阐明了神经基板的能力，调制机械阻抗的肢体，因为我们在运动适应学习。使用静息态功能磁共振成像分析，我们证明了一个分布式小脑顶叶额叶网络的功能，以调节肌肉的共同收缩与小脑作为其关键组成部分。
As we learn to perform a motor task with novel dynamics, the central nervous system must adapt motor commands and modify sensorimotor transformations. The objective of the current research is to identify the neural mechanisms underlying the adaptive process. It has been shown previously that an increase in muscle co-contraction is frequently associated with the initial phase of adaptation and that co-contraction is gradually reduced as performance improves. Our investigation focused on the neural substrates of muscle co-contraction during the course of motor adaptation using a resting-state fMRI approach in healthy human subjects of both genders. We analyzed the functional connectivity in resting-state networks during three phases of adaptation, corresponding to different muscle co-contraction levels and found that change in the strength of functional connectivity in one brain network was correlated with a metric of co-contraction, and in another with a metric of motor learning. We identified the cerebellum as the key component for regulating muscle co-contraction, especially its connection to the inferior parietal lobule, which was particularly prominent in early stage adaptation. A neural link between cerebellum, superior frontal gyrus and motor cortical regions was associated with reduction of co-contraction during later stages of adaptation. We also found reliable changes in the functional connectivity of a network involving primary motor cortex, superior parietal lobule and cerebellum that were specifically related to the motor learning.Significance StatementIt is well known that co-contracting muscles is an effective strategy for providing postural stability by modulating mechanical impedance and thereby allowing the central nervous system to compensate for unfamiliar or unexpected physical conditions until motor commands can be appropriately adapted. The present study elucidates the neural substrates underlying the ability to modulate the mechanical impedance of a limb as we learn during motor adaptation. Using resting-state fMRI analysis we demonstrate that a distributed cerebellar-parietal-frontal network functions to regulate muscle co-contraction with the cerebellum as its key component.