Forward Models, the Cerebellum and Development

描述(申请人提供)：为了在我们的一生中做出准确的动作，人们认为我们的大脑形成了我们身体和环境的内部模型。当我们的身体和与我们互动的环境发生变化时，这些内部模型就会适应。一种理论内部模型是前向模型(FM)，它预测我们的运动指令的感觉结果，并为我们提供预测误差来驱动适应。尽管Fms被用来在计算上模拟运动适应，但很少有实验试图找到Fms在大脑中的神经基础。此外，在适应期间，我们目前还没有方法来估计在不同的试验中，有多少马达输出的变化是由于FM的适应。在这里，我们提出了一种新的方法，用来量化FM在REACH期间的逐个试验的适应。使用这种新方法，我们可以通过测试患者群体来寻找FMS的神经底物。研究表明，小脑是FMS最可能的部位，并证明小脑损伤会导致适应障碍。最近，我们发现，小脑受试者能够改变他们的运动输出，以应对逐渐引入的扰动。如果FM依赖于小脑，那么应该有一些场景，在这些场景中，受试者的小脑表现出运动输出的正常变化，而FM则出现异常变化。我们的新实验方法将使我们能够检验这一预测。在发育过程中，小脑的成熟速度比大脑慢。这被怀疑是幼儿表现出与小脑受试者相似的异常运动适应模式的潜在原因。这与人们普遍认为幼儿比成年人更善于学习的看法背道而驰。我们假设，随着小脑的发育，适应更强烈地依赖于FM。除了健康对照，测试这些组还将提供一幅关于FM的重要新图景--它们如何影响我们的运动，它们的生物学基础，以及它们如何存在于我们的大脑中。 公共卫生相关性：这项研究旨在加深对人们如何从运动错误中学习的理解。我们希望确定大脑的哪个区域负责这种能力，以及它是如何在童年期间发展起来的。这将是改善与运动康复和发育障碍相关的治疗的重要知识。

DESCRIPTION (provided by applicant): In order to make accurate movements throughout our lifetime, it is thought that our brain forms internal models of our body and our environment. These internal models adapt as our body and the environment that we interact with undergo changes. One type of theoretical internal model is a forward model (FM), which makes predictions about the sensory consequences of our motor commands, and provides us with prediction errors to drive adaptation. Though FMs are used computationally to model motor adaptation, there have been few experiments that have attempted to find the neural basis of FMs in the brain. Furthermore, during adaptation, we currently have no method with which to estimate how much of the change in the motor output from trial to trial is due to adaptation of FMs. Here, we present a new method with which to quantify adaptation of FMs on a trial-by-trial basis during reaching. Using this new method, we can look for the neural substrates of FMs by testing patient populations. Studies implicate the cerebellum as the most likely location for FMs, and demonstrate that cerebellar damage leads to deficits in adaptation. Recently we discovered that cerebellar subjects are able to change their motor output in response to a gradually introduced perturbation. If FMs depend on the cerebellum, then there should be scenarios in which cerebellar subjects show normal changes in motor output, with abnormal changes in FMs. Our new experimental method will allow us to test this prediction. During development, the cerebellum matures more slowly than the cerebrum. This is suspected to be the underlying reason for why young children show abnormal patterns of locomotor adaptation, resembling that of cerebellar subjects. This runs against the common belief that young children are better learners than adults. We hypothesize that with development of the cerebellum, adaptation relies more strongly on FMs. Testing these groups, in addition to healthy controls, will provide a significant new picture of FMs - how they affect our movements, their biological underpinnings, and how they come to exist in our brains. PUBLIC HEALTH RELEVANCE: This research is geared towards developing a deeper understanding of how people learn from movement errors. We hope to determine which area of the brain is responsible for this ability and how it develops through childhood. This will be important knowledge for the improvement of therapeutics relating to motor rehabilitation and developmental disorders.