Neural mechanisms of predictive movement planning

计划和执行协调的运动是非常复杂的，但似乎只需要很少的有意识的努力，除了最初的决定，以实现预期的目标。尽管表面上看起来很简单，但这样的动作需要一系列复杂的感觉运动转换，利用视觉、本体感觉、皮肤和前庭信息。基本计划和执行过程的复杂性从感觉运动障碍患者面临的挑战中可见一斑，这些患者难以进行简单的日常生活活动。我的研究利用KINARM机器人系统来更好地了解这些规划和执行过程。我们使用这个设备来评估不同感觉反馈条件下的运动轨迹，并在这些轨迹期间应用扰动来探索进行在线校正的能力。此外，我们使用经颅磁刺激(TMS)来检查不同皮质和皮质下部位对计划和执行过程的贡献。最后，通过让参与者在站立时执行这些任务，我们还可以确定运动规划和在线校正如何与预期和反应性姿势调整相互作用。通过这些方法，我们可以获得站立姿势上肢运动的综合计划和执行的综合图景，以及被认为参与这些过程的特定大脑部位的假定贡献。运动规划的关键特征之一是它的预测性。这既可以在肢体运动本身的特征中观察到，也可以在运动开始前姿势调整的预期性质中观察到。这些预测机制是如何受运动的复杂性和注意过程的影响程度影响的，目前还知之甚少。此外，目前尚不清楚影响肢体运动计划和执行的不同神经回路如何影响大脑中的姿势控制中心。因此，本研究的目的是研究1)站立姿势控制和上肢运动之间的相互作用；2)注意力在这些相互作用中所起的作用；3)预期和反应性姿势反应对受干扰和未受干扰的上肢运动的贡献；以及4)顶叶和辅助运动区以及小脑外侧区对这些过程的不同贡献。本申请中提出的实验将使我们更好地了解上肢运动的规划和执行过程，它们如何与站立姿势控制相结合，以及顶叶和辅助运动区以及外侧小脑在这一整合中所起的作用。这些信息可以用来更好地为当前的肢体运动控制理论提供信息。

Planning and executing coordinated movement is remarkably complex, yet appears to take very little conscious effort beyond the initial decision to achieve a desired goal. Despite this apparent simplicity, such movements require a complex series of sensorimotor transformations that make use of visual, proprioceptive, cutaneous, and vestibular information. The complexity of the underlying planning and execution processes is made clear by the challenges faced by patients with sensorimotor deficits who have difficulty carrying out simple activities of daily living. My research makes use of the KINARM robot system to gain a better understanding of these planning and executions processes. We use this device to assess movement trajectories under varying sensory feedback conditions and apply perturbations during these trajectories to probe the ability to make on-line corrections. In addition, we use transcranial magnetic stimulation (TMS) to examine the contribution of different cortical and subcortical sites to the planning and execution processes. Finally, by having participants perform these tasks while standing, we can also determine how movement planning and on-line corrections interact with anticipatory and reactive postural adjustments. By these means, we can obtain a comprehensive picture of the integrated planning and execution of upper limb movements in a standing posture and the putative contributions from specific brain sites thought to be involved in these processes. One of the key features of movement planning is its predictive nature. This is observed both within the features of limb movements themselves as well as in the anticipatory nature of postural adjustments prior to movement onset. How these predictive mechanisms are affected by the complexity of the movement and the extent to which attentional processes contribute is currently poorly understood. In addition, it is not known how different neural circuits which contribute to limb movement planning and execution also influence or are influenced postural control centres in the brain. Thus, the objectives of the current proposal are to examine 1) the interaction between standing postural control and upper limb movements; 2) the role attention plays in these interactions; 3) the contribution of anticipatory versus reactive postural responses to perturbed and unperturbed upper limb movements; and 4) the different manner in which parietal and supplementary motor areas and lateral cerebellum contribute to these processes. The experiments proposed in this application will allow us to better understand the planning and execution processes of upper limb movements, how they are integrated with standing postural control, and the role played by parietal and supplementary motor areas and the lateral cerebellum in this integration. This information can be used to better inform current theories of limb motor control.**