Role of Prefrontal Cortex in Locomotor Learning

 描述(由申请人提供)：步态功能是老年人和运动障碍患者总体健康和生活质量的有力预测指标。然而，我们通过康复恢复健康步态模式的能力受到缺乏对神经系统如何学习和存储新步态模式的理解的限制。这项提议旨在促进我们对影响运动学习的大脑结构的理解，并研究如何通过非侵入性刺激来操纵这些结构中的活动来增强学习。具体地说，我们将关注前额叶皮质及其在策略性和适应性运动学习中的作用。前额叶皮质参与认知功能、步态调节和多种运动学习机制(包括策略性学习和适应性学习)。在这里，我们将研究前额叶对运动学习的贡献，以及重要的是，我们是否可以操纵前额叶活动来增强学习。目标1考察自适应运动学习过程中错误大小如何影响明确回忆扰动的能力。我们观察到，在分裂带跑步机行走过程中，突然的适应会导致更快的重新学习(即储蓄)，而逐渐适应不会。我们认为，在逐步适应之后，可能不会节省成本，因为小误差提供的关于扰动大小(即皮带速度之间的差异)的明确信息很少。我们还怀疑，检测扰动并确定它是否以前经历过的能力可能是由额叶介导的，因为有前额叶损害的人很难检测到上肢运动的扰动。目的2研究兴奋性(阳极)和抑制性(阴极)经颅直流电刺激(Tdcs)对脑电活动的影响。 在适应性运动学习中，前额叶皮质影响对扰动的外显回忆，而在策略性运动学习中，前额皮质影响对所学知识的保留。这一信息可能会为步态康复开辟一条新的途径，因为它证明了tDCs可以刺激前额叶皮质，以增强运动学习。在目的3中，我们研究了前额叶tdcs对小脑损伤者策略性运动学习的影响。有小脑损伤的人表现出适应性运动学习障碍。因此，需要其他机制来促进这一群体中的运动学习。我们将尝试使用前额叶tdcs来加强小脑损伤患者的战略性运动学习。这项建议的目的是了解前额叶皮质在适应性和策略性运动学习中的作用，并研究如何操纵前额叶皮质的活动来增强这些学习机制。这一建议的发现可能会对步态康复产生深远的影响，因为它促进了对运动学习涉及的神经机制的理解，并提供了非侵入性脑刺激可以增强战略性和适应性运动学习的直接证据。

 DESCRIPTION (provided by applicant): Gait function is a strong predictor of general health and quality of life in older adults and persons with movement disorders. However, our ability to restore healthy gait patterns through rehabilitation is limited by a lack of understanding about how the nervous system learns and stores new gait patterns. This proposal aims to advance our understanding of the brain structures that influence locomotor learning and investigate how activity in these structures can be manipulated with non-invasive stimulation to enhance learning. Specifically, we will focus on the prefrontal cortex and its role in strategic and adaptie locomotor learning. The prefrontal cortex has been implicated in cognitive function, gait modulation, and multiple mechanisms of motor learning (including strategic and adaptive learning). Here, we will investigate prefrontal contributions to locomotor learning and, importantly, whether we can manipulate prefrontal activity to enhance learning. Aim 1 examines how error size during adaptive locomotor learning affects the ability to explicitly recall a perturbation. We have observed that, during split-belt treadmill walking, abrupt adaptation leads to faster relearning (i.e., savings) while gradual adaptation does not. We think that savings might be absent following gradual adaptation because small errors provide little explicit information about the magnitude of the perturbation (i.e., difference between belt speeds). We also suspect that the abilities to detect a perturbation and determine whether it has been previously-experienced may be frontally-mediated, as persons with prefrontal lesions have difficulty detecting perturbations in upper extremity movements. Aim 2 investigates how excitatory (anodal) and inhibitory (cathodal) transcranial direct current stimulation (tDCS) of the prefrontal cortex affects explicit recall of a perturbation during adaptive locomotor learning and retention of what has been learned during strategic locomotor learning. This information could open a new avenue for gait rehabilitation by demonstrating that the prefrontal cortex can be stimulated with tDCS to enhance locomotor learning. In Aim 3, we study the effects of prefrontal tDCS on strategic locomotor learning in persons with cerebellar damage. Persons with cerebellar damage demonstrate adaptive motor learning impairments. Accordingly, alternative mechanisms are required to facilitate locomotor learning within this population. We will attempt to enhance strategic locomotor learning in persons with cerebellar damage using prefrontal tDCS. The goals of this proposal are to understand the role of the prefrontal cortex during adaptive and strategic locomotor learning and to investigate how to manipulate activity of the prefrontal cortex to enhance these learning mechanisms. The findings of this proposal could have a profound impact on gait rehabilitation by advancing the understanding of the neural mechanisms involved in locomotor learning and providing direct evidence that non-invasive brain stimulation can enhance strategic and adaptive locomotor learning.