Muscle Re-Assembly in MI During Skill Acquisition

技能习得过程中 MI 中的肌肉重新组装

• 批准号: 6540316
• 负责人: Donald R. Humphrey
• 金额: $ 30.24万
• 依托单位: EMORY UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-04-01 至 2004-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6540316
• 关键词: Macaca mulatta; behavior test; behavioral /social science research tag; brain mapping; electrodes; electromyography; histology; learning; magnetic resonance imaging; motor cortex; muscle function; neural information processing; neural plasticity; neuroanatomy; neuromuscular system; performance; spinal cord

DESCRIPTION:(from applicant's abstract) It is now clear that motor cortical maps may undergo dynamic changes as new motor skills are acquired. Many studies have shown that the motor map of a body part may expand and become more excitable when that part is used in a new motor skill. Conversely, nearby, task-unrelated motor/muscle maps may shrink. The involvement of both excitatory and inhibitory processes has been shown, and the cellular mechanisms underlying these changes, including synaptic plasticity in intracortical horizontal connections, have been proposed. Significantly, however, we have as yet no clear understanding of how such changes in map size or configuration may contribute to the programming of new muscle synergies as a new skill is acquired. This application addresses this important problem. Using chronically implanted intracortical and EMG electrode arrays, we have tracked changes in the maps for task-related, single muscles, in the precentral (MI) motor cortex of an alert monkey, as it learned successive variants of a visuomotor, forelimb tracking task. Unexpectedly, we found that skill acquisition was marked by a fractionation of cortical muscle maps rather than an expansion. In addition, fractionated components of different muscle maps were observed to "move" into or out of spatial correlation with one another, as new tasks were acquired. We propose that such fractionation and re-assembly of MI muscle maps may contribute to and/or reflect the development of new muscle synergies during skill acquisition. Experiments are proposed here that will allow us to obtain new evidence for or against this hypothesis. In addition, we will examine: (a) the extent to which these learning induced changes in cortical muscle maps reflect intracortical as opposed to spinal sites of plasticity; (b) the extent to which changing cortical maps and related muscle synergies are reversible; and (c) the potentially confounding effects of repeated microstimulation in measuring cortical motor maps. Together, these experiments will provide important new evidence about the relationship between cortical map plasticity and the reprogramming of intramuscular coordination as new skills are acquired.

描述：（来自申请人摘要） 现在很清楚，运动皮层地图可能会经历动态变化， 获得运动技能。许多研究表明，身体的运动地图 当该部件用于新的发动机时，该部件可能会膨胀并变得更易兴奋 技能相反，附近与任务无关的运动/肌肉地图可能会缩小。的 参与兴奋性和抑制性过程已被证明， 这些变化背后的细胞机制，包括突触可塑性， 皮质内水平连接。重要的是， 然而，我们还没有清楚地了解地图大小的这种变化是如何发生的， 或配置可能有助于新的肌肉协同作用的编程， 新的技能获得。这个应用程序解决了这个重要的问题。使用 长期植入的皮质内和EMG电极阵列，我们已经跟踪 中央前肌（MI）中任务相关的单个肌肉的地图变化 一个警觉的猴子的运动皮层，因为它学习了一个连续的变体， 视觉，前肢跟踪任务。出乎意料的是，我们发现， 采集通过皮层肌肉图的分级而不是 一个扩展。此外，不同肌肉图的细分组件 被观察到“移动”进入或离开彼此的空间相关性， 获得了新的任务。我们建议，这种分馏和重组的 MI肌肉图可能有助于和/或反映新肌肉的发育 在技能获取过程中的协同作用。这里提出的实验将 让我们获得支持或反对这一假设的新证据。另外我们 将研究：（a）这些学习在多大程度上引起了变化， 皮质肌肉地图反映了皮质内，而不是脊髓部位， 可塑性;（B）改变皮质映射和相关肌肉 协同作用是可逆的;以及（c） 重复微刺激测量皮质运动地图。所有这些 实验将提供重要的新证据， 皮层地图可塑性和肌肉协调的重新编程， 新的技能被获得。