Preparation and Control of Movement

我们的许多行动都是由环境的变化引发的，其中大部分行动都可以在预期的变化之前做好准备。当在这些反应情况下观察到熟练的人类动作时，人们可能会忘记动作准备、启动和执行之间所需的精细同步，而每一个动作对有效控制动作都至关重要。这些过程的成功和失败可以在日常生活中的许多情况下看到，从奥运会短跑运动员准备快速出发，优雅平稳地追求他们的目标，到帕金森氏症患者，尽管似乎是最大的认知努力，但未能在路边的路边开始一个看似简单的步骤，并冻结。该提案将研究人们如何使用各种方法在各种环境背景下准备、发起和控制他们的行动。我们过去使用的一种方法效果很好，那就是通过发出一个令人吃惊的刺激沿着“go”命令来探测运动准备的过程。这种短暂的响亮声音会引起惊吓反射，但似乎也会触发和释放任何计划好的、储存好的、准备好开始的自主运动。事实上，当我们考虑前面提到的两个例子时，已经表明短跑运动员的非常快的反应时间（小于100毫秒）可能是像触发器一样的惊吓的结果，而不是错误的开始。我们还表明，惊恐可以非常顺利和毫不费力地触发帕金森病患者的准备运动。因为我们已经了解了惊吓反射的路径，所以当它与这个反射相互作用时，就有可能映射运动准备和启动。这项建议旨在继续我们的研究工作，以调查运动准备和启动使用的技术，如惊吓。第一系列实验将研究一组肌肉如何准备产生快速，准确和流畅的运动。虽然我们通过将四肢移动到太空中的目标来轻松有效地与环境进行交互，但单个关节上肌肉协同作用的编程和控制仍然没有得到清楚的理解。最近，我们提出，激动剂/拮抗剂协调活动可能是由皮质和皮质下的大脑结构控制。在这里，我们建议调查是否小脑参与调制的幅度和/或时间的协调行动作为一个简单的三相（激动剂-拮抗剂-激动剂）肌肉爆发的活动。第二个系列的实验探讨了复杂动作的反应准备。我们以前的大多数研究使用惊吓来探测简单的运动准备，手腕或肘部伸展的单一成分运动。然而，多成分运动的准备，定时和排序过程需要高水平的协调，这也将使用惊人的刺激来研究。我们的第三个系列实验将研究当一个惊人的声音触发一个准备好的反应时所涉及的过程。具体来说，我们将研究实验方案，这些方案可以区分已经提出的各种解释，以解释这种被称为StartReact效应的预期反应的触发。最后，我们将研究惊吓的实验指标。在我们实验室进行的许多研究已经成功地使用了一个响亮的声音刺激，以检查在各种情况下的反应准备过程。然而，我们不断评估我们的实验方法，以确保我们的结果是有效的和可重复的。

Many of our actions are triggered by changes in the environment and most of these actions can be prepared in advance of the anticipated change. When skillful human action is observed in these reactive situations one may be oblivious to the fine synchronization that is required between movement preparation, initiation and execution and yet each is vital to the effective control of action. Success and failure of these processes can be seen in many situations in everyday life, from the Olympic sprinter who prepares for a fast start out of the blocks in elegant smooth pursuit of their goal, to the Parkinson’s disease patient who fails to initiate a seemingly simple step over a roadside curb and freezes despite what appears to be maximum cognitive effort. This proposal will examine how people prepare, initiate and control their actions in various environmental contexts using a variety of methodologies. One method we have used to good effect in the past is to probe the processes of movement preparation by delivering a startling stimulus along with the “go” command. This brief loud sound causes a startle reflex but also appears to trigger and release any voluntary movement that is planned, stored and ready to initiate. Indeed when we consider the two examples mentioned earlier it has been shown that very fast reaction times of the sprinter (less than 100 milliseconds) may be the result of a startle like trigger and not a false start. We have also shown that startle can trigger prepared movements quite smoothly and effortlessly in patients with Parkinson’s disease. Because we have an understanding of the pathways responsible for the startle reflex, it then becomes possible to map movement preparation and initiation as it interacts with this reflex. This proposal is designed to continue our research efforts into the investigation of motor preparation and initiation using techniques such as startle. The first series of experiments will investigate how a group of muscles are prepared to produce fast, accurate and smooth movements. Although we easily and effectively interact with our environment by moving our limbs to targets in space, the programming and control of muscle synergies across a single joint is still not clearly understood. Recently we suggested that agonist/antagonist coordinated activity may be controlled by both cortical and subcortical brain structures. Here we propose to investigate whether the cerebellum is involved in modulating the amplitudes and/or timing of such coordinated actions as a simple triphasic (agonist-antagonist-agonist) muscle burst of activity. A second series of experiments explores response preparation for complex movements. Most of our previous studies used startle to probe movement preparation with simple, single component movements of either wrist or elbow extension. However, the process of preparing, timing and sequencing of multi-component movements requires high levels of coordination, which will also be studied using a startling stimulus. Our third series of experiments will examine the processes involved when a startling sound triggers a prepared response. Specifically we will examine experimental protocols that can differentiate between the various explanations that have been put forward to account for this triggering of intended responses known as the StartReact effect. Finally we will investigate the experimental indicators of startle. Many studies conducted in our lab have successfully used a loud acoustic stimulus to examine the process of response preparation under a variety of circumstances. However, we are constantly evaluating our experimental methodology to ensure our results are valid and reproducible.