Understanding the physiological role of the cerebellum on human motor learning

描述(由申请人提供)：本方案的目标是了解小脑对不同形式的运动学习的生理贡献：适应和技能学习。众所周知，小脑(CB)参与适应性学习，通过重新校准运动动力学来满足可预测的需求。标定感觉运动动力学可以转化为几个运动过程，并且对于产生准确的动作是必不可少的。因此，CB似乎也可能以这种方式为技能学习做出贡献。从CB在学习感觉运动校准中起关键作用的前提出发，我们计划测试小脑在适应性和技能运动学习中的生理作用。我们将使用经颅磁刺激(TMS)来探索健康受试者CB和运动皮质(CBI)之间的连接，以获得关于小脑在运动学习中的生理作用的信息。我们预测，CBI只会在学习或转移效应器中发生变化，遵循体视学的特定规则，在适应期间和技能运动学习的早期。此外，技能学习过程中的变化将与学习感觉运动校准有关，而不是与序列相关的学习。具体目标1将检验我们的假设，即CBI的变化是躯体特异性的。为了做到这一点，实验1将使用已知在手臂和手之间不对称转移的视觉运动适应任务来确定CBI的变化是躯体定位特有的还是表明弥漫性小脑变化。我们的初步结果与先前的研究一致，该研究表明学习从手臂转移到手，并且CBI对两个效应器都有变化。在具体目标2中，我们将检验CBI在技能学习过程中早期减少的假设。在实验2中，我们将评估参与者的CBI，这些参与者要么学习等距手指捏序列技能任务，要么执行没有学习的随机任务。我们的初步数据显示，对于那些学习了这项任务的人来说，CBI的变化发生得更早。由于学习技能任务涉及两个主要组成部分，(1)获得感觉运动映射以成功使用感觉运动夹紧力传感器，(2)学习任务中嵌入的序列，我们将进行实验3。在这里，我们将理清CBI变化与学习感觉运动校准或学习任务序列有关。为此，我们将在参与者学习感觉运动校准(没有目标序列)之前和之后以及参与者学习目标序列之前和之后测试CBI。我们的初步行为数据表明，重复接触感觉运动映射可以改善技能任务的习得和整体表现。这一提议的结果将进一步加深我们对小脑在人类运动学习中的作用的理解。这一点很重要，因为经常经历运动障碍的神经科患者需要使用运动学习策略来改善他们的恢复。因此，了解小脑对运动学习和整体功能的贡献有助于制定旨在增强行为的康复策略。

DESCRIPTION (provided by applicant): The goal of this proposal is to understand the physiological cerebellar contributions to different forms of motor learning: adaptation and skill learning. The cerebellum (CB) is known to be engaged in adaptive learning by recalibrating movement dynamics to meet predictable demands. Calibrating sensorimotor dynamics can translate to several motor processes and is essential for producing accurate movements. Thus, it seems likely that the CB also contributes to skill learning in this fashion. Starting from the premise that the CB is crucially involved in learning sensorimotor calibrations, we plan to test the cerebellar physiological role during adaptive and skill motor learning. We will use transcranial magnetic stimulation (TMS) to explore the connectivity between the CB and motor cortex (CBI) in healthy participants to gain information about the cerebellar physiological role during motor learning. We predict that CBI will change only in the learning or transferred effector, following a somatotopic specific rule, during adaptation and early on during skill motor learning. Furthermore, the changes during skill learning will be related to learning sensorimotor calibrations, rather than sequence related learning. Specific Aim 1 will test our hypothesis that changes in CBI are somatotopic specific. To do this, Experiment 1 will use a visuomotor adaptation task known to transfer asymmetrically between the arm and hand to determine whether changes in CBI are somatotopic specific or indicate a diffuse cerebellar change. Our preliminary results are consistent with prior studies demonstrating that learning transfers from arm to hand, and that CBI changes for both effectors. In Specific Aim 2, we will test the hypothesis that CBI will be reduced early during skill learning. In experiment 2 we will assess CBI in participants that either learn an isometric finger-pinch sequence skill task or perform a random task where no learning occurs. Our preliminary data shows that CBI changes occur early on for those who learned the task. Since learning the skill task involves two main components, (1) acquiring a sensorimotor mapping to successfully use the sensorimotor pinch force transducer and (2) learning the sequence embedded in the task, we will perform experiment 3. Here, we will disentangle whether CBI changes are related to learning a sensorimotor calibration or learning the sequence of the task. To this end, we will test CBI before and after participants learn a sensorimotor calibration (without a sequence of targets), as well as before and after participants learn the sequence of targets. Our preliminary behavioral data shows that repeated exposure to the sensorimotor mapping improves both the acquisition and overall performance of the skill task. The results from this proposal will further our understanding of the cerebellar role in human motor learning. This is important because neurological patients who frequently experience motor impairment need to use motor learning strategies to improve their recovery. Thus, understanding the contributions of the cerebellum to motor learning and overall function can help develop rehabilitation strategies aimed to enhance behavior.