Brain - Spinal cord functional contributions to the learning of motor skills

在过去的25年里，我研究了运动技能学习不同阶段背后的行为决定因素、神经基础和神经生理机制。运动技能学习是指通过使用心理物理、多模式神经成像方法和先进的分析技术，通过反复练习来轻松地执行动作的过程。我的初步工作揭示了皮质-纹状体和皮质-小脑系统的特殊贡献，以及它们在早期学习阶段与海马体的相互作用，从而促进了运动技能行为的巩固、自动化和长期保持。 然而，近年来，我的团队也开发并应用了开创性的技术，允许在参与者执行运动学习任务时同时记录大脑和颈髓活动。这种创新方法之所以至关重要，主要有两个原因。首先，鉴于中枢神经系统的这一部分位于大脑和效应器之间，现在很明显，如果我们不考虑脊髓参与这一过程，我们对介导运动技能学习的神经底物的理解是不完整的。其次，尽管研究人员传统上将注意力分别放在大脑和脊髓上，但这两个结构构成了一个系统，作为一个整体参与行为产生和运动学习。例如，使用这些方法，我的工作表明，一种类型的运动技能(运动序列学习)不仅依赖于大脑的可塑性(即学习后的长期变化)，还依赖于固有的脊髓可塑性，以及特定的脑-脊髓相互作用模式。此外，我们还报告了脊髓有助于运动学习的后期阶段(即经过一周的练习)的证据。 因此，虽然我们的工作拓宽了我们对神经基质介导运动学习的知识，但还需要进一步研究脊髓和脑-脊髓的相互作用，不仅要解决这一领域脊髓神经成像研究的匮乏，而且最重要的是，我们关于大脑和脊髓对获得运动技能的贡献的知识水平之间的差异。 为此，在目前的5年资助续期建议中，我们打算继续我们的研究计划，并进行一系列研究，以探讨在获得不同运动技能(即运动适应)、感觉运动刺激和从左手运动技能向右手运动技能迁移过程中，专家与新手之间的功能性脑-脊髓相互作用。 这一研究计划将极大地推动运动学习领域的发展，因为它考虑到了所有水平的中枢神经系统在这一过程中的贡献，并为其他寻求在其他研究领域采用相同方法的研究人员提供了一个样板。

Over the past 25 years, I have investigated the behavioral determinants, neural substrates and neurophysiological mechanisms underlying different phases of motor skill learning the process by which movements come to be performed effortlessly through repeated practice using psychophysical, multimodal neuroimaging methods and advanced analysis techniques. My initial work has uncovered the specialized contributions of the cortico-striatal and cortico-cerebellar systems, as well as their interaction with the hippocampus in the early learning phase, which subsequently facilitate the consolidation, automatization and long-term retention of motor skilled behavior. In recent years, however, my team has also developed and applied pioneering techniques that allow the simultaneous recording of brain and the cervical spinal cord activity while participants execute motor learning tasks. This innovative approach has been crucial for two main reasons. First, it is now clear that our understanding of the neural substrate mediating motor skill learning cannot be complete if we do not account for the spinal cord involvement in this process, given that this part of the central nervous system is located between the brain and effectors. Second, even though researchers have traditionally focus separately on brain and spinal cord, these two structures constitute a system that is involved in behavior production and motor learning as a unitary entity. Using these approaches, my work has shown, for example, that one type of motor skill (motor sequence learning) relies not only on brain plasticity (i.e. long lasting changes following learning), but also on intrinsic spinal plasticity, as well as in specific brain-spinal cord interaction patterns. Furthermore, we have also reported evidence that the spinal cord contributes to the late phase of motor learning (i.e. after a week-long practice). Thus while our work has broaden our knowledge of neural substrates mediating motor learning, further investigation of the spinal cord and brain-spinal cord interaction is needed to address not only the scarcity of spinal cord neuroimaging studies in this area, but, most importantly, the discrepancy between our knowledge levels regarding the brain versus spinal cord's contribution to the acquisition of motor skills. To this end, in the current 5-year grant renewal proposal, we intend to continue our research program and conduct a series of studies that will investigate the functional brain-spinal cord interactions during acquisition of a different motor skill (i.e. motor adaptation), sensorimotor stimulation and during motor skill transfer from the left-hand to right-hand in experts vs. novices. This research program will greatly advance the field of motor learning by accounting for the contribution of all level of the central nervous system in this process, and by serving as a model for other researchers seeking to employ the same approaches in other research areas.