Neural and Muscular Control of Finger Movements

描述(申请人提供)：能够相对独立地移动手指，使人类和非人类灵长类动物能够操纵环境中的各种物体，并执行各种动作和手势。运动皮质的损伤，如与中风相关的损伤，会导致单独移动手指的能力持续存在缺陷，即使控制其他肢体节段的能力已经恢复。中风后手指灵活性的严重损害可能是因为多块肌肉之间需要异常复杂的协调才能产生即使是简单的手指运动。然而，关于中枢神经系统如何协调肌肉群来减少手指和手的运动，人们知之甚少。因此，这个项目的主要目标是确定神经机制，通过这种机制，多个肌肉的活动在手指运动的详细阐述中得到协调。具体地说，对受试者不同手部肌肉中运动单位的发射时间进行交叉相关分析，将被用来估计肌肉之间的协调活动在多大程度上是由于下行通路的分歧，这些下行通路提供了跨运动核组的共同突触输入。这些具体目标旨在确定手部肌肉是如何组合成四种不同形式的协同活动的功能组的：1)插入多个手指的多腱肌肉之间的协调，2)插入同一手指的单独肌肉的协调，3)插入不同手指但习惯性地一起用于特定功能的单独肌肉的协调，以及4)手指主动者与其活动提供有效手指运动所需的关节稳定所需的肌肉之间的协调。这些研究将扩大我们对大脑控制随意运动的机制的了解，并可能为与中风相关的运动功能障碍的原因提供重要的见解。

DESCRIPTION (provided by applicant): The ability to move the fingers relatively independently of one another enables humans and non-human primates to manipulate diverse objects in the environment and to execute an immense variety of movements and gestures. Lesions of the motor cortex, such as those associated with stroke, give rise to persistent deficits in the ability to move the fingers individually even though the capacity to control other limb segments recovers. Such severe impairment in finger dexterity following stroke might arise because of the unusually complex coordination required among multiple muscles to produce even simple finger movements. However, little is known about how the central nervous system orchestrates ensembles of muscles to 3roduce movements of the fingers and hand. The broad goal of this project, therefore, is to identify the neural mechanisms whereby the activities of multiple muscles are coordinated in the elaboration of finger movements. Specifically, cross-correlation analysis of the firing times of motor units located in different hand muscles of human subjects will be used to estimate the extent to which coordinated activity among muscles is due to divergence of descending pathways providing common synpatic input across sets of motor nuclei. The specific aims are designed to identify how hand muscles are assembled into functional groups for four widely different forms of synergistic activity that underlie: 1) the coordination of compartments of multi-tendoned muscles that insert upon multiple digits, 2) the coordination of separate muscles that insert upon the same digit, 3) the coordination of separate muscles that insert upon different digits yet are used habitually together for specific functions, and 4) the coordination between prime movers of digits and muscles whose activity provides joint stabilization necessary for effective digit movements. These studies will expand our knowledge of the mechanisms by which the brain controls voluntary movements and may provide important insights into the causes of motor dysfunction associated with stroke.