Neural and Muscular Control of Finger Movements

描述（由申请人提供）：相互相对独立地移动手指的能力使人类和非人类灵长类动物能够操纵环境中的各种物体，并执行各种各样的运动和手势。运动皮层的损伤，例如与中风相关的损伤，会导致单独移动手指的能力持续缺陷，即使控制其他肢体部分的能力恢复。中风后手指灵活性的严重损害可能是由于多块肌肉之间异常复杂的协调所导致的，即使是简单的手指运动。然而，人们对中枢神经系统如何协调肌肉群来产生手指和手的运动知之甚少。因此，这个项目的主要目标是确定神经机制，从而协调多个肌肉的活动，在手指运动的阐述。具体而言，位于人类受试者的不同手部肌肉中的运动单元的发射时间的互相关分析将用于估计肌肉之间的协调活动是由于下行通路的发散而导致的程度，下行通路提供跨运动核组的共同突触输入。具体目标旨在确定手部肌肉是如何组装成功能组的四种不同形式的协同活动，这些活动是：1）插入多个手指的多腱肌肉的隔室的协调，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）手指的原动者与肌肉之间的协调，肌肉的活动提供有效手指运动所必需的关节稳定性。这些研究将扩大我们对大脑控制自主运动机制的了解，并可能为了解与中风相关的运动功能障碍的原因提供重要见解。

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.