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

在过去的25年里，我利用心理物理学、多模态神经成像方法和先进的分析技术，研究了运动技能学习不同阶段的行为决定因素、神经基质和神经生理机制——通过反复练习，运动可以毫不费力地完成的过程。我最初的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，这些相互作用随后促进了运动技能行为的巩固、自动化和长期保留。然而，近年来，我的团队也开发并应用了开创性的技术，允许参与者在执行运动学习任务时同时记录大脑和颈椎脊髓的活动。这种创新的方法之所以至关重要，主要有两个原因。首先，考虑到中枢神经系统的脊髓部分位于大脑和效应器之间，如果我们不考虑脊髓在这一过程中的参与，现在很清楚，我们对神经基质介导运动技能学习的理解是不完整的。其次，尽管研究人员传统上分别关注大脑和脊髓，但这两个结构构成了一个系统，作为一个统一的实体参与行为产生和运动学习。使用这些方法，我的工作已经表明，例如，一种运动技能（运动序列学习）不仅依赖于大脑的可塑性（即学习后的持久变化），而且还依赖于内在的脊髓可塑性，以及特定的脑脊髓相互作用模式。此外，我们还报道了脊髓有助于运动学习后期（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认识，但需要进一步研究脊髓和脑脊髓相互作用，以解决这一领域脊髓神经影像学研究的缺乏，但最重要的是，我们对大脑和脊髓对运动技能习得的贡献的知识水平之间的差异。为此，在当前的5年拨款更新提案中，我们打算继续我们的研究计划并进行一系列研究，以调查专家与新手在获得不同运动技能（即运动适应），感觉运动刺激以及从左手到右手的运动技能转移过程中的脑脊髓功能相互作用。这一研究项目将极大地推动运动学习领域的发展，因为它考虑了中枢神经系统在这一过程中各个层面的贡献，并为其他研究人员寻求在其他研究领域采用同样的方法提供了一个模型。

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.