Understanding the neural basis of motor development in early childhood

熟练运动能力的获得是人类发展中最重要的方面之一。然而，精细运动控制和协调直到学龄前才接近成人的稳定模式，这一时期也出现了许多运动障碍。我们对运动控制的潜在神经发育知之甚少，尽管我们知道大脑结构和功能在儿童早期都经历了巨大的变化。通过对学龄前儿童的脑磁图（MEG）功能测量，我们最近证明，直到学龄前儿童之后，与运动相关的大脑活动才表现出成人的模式。对非人类灵长类动物的研究表明，运动皮层及其相关的传出通路在出生后的神经组织中发生了显著的变化。这包括源于后运动皮层的系统发育上的新运动通路的延迟成熟，该运动通路与脊髓运动神经元直接相连，皮质神经元（CM）通路对精细运动控制至关重要，如灵巧的手部运动。这表明该运动系统的成熟也发生在人类发育的后期，但这种变化从未被直接测量过，也不知道它们对正常运动发育的影响。在本研究中，我们将首次将非侵入性神经成像技术（功能性MEG和结构MRI）与6至10岁典型发育儿童精细运动技能评估的运动学测量相结合，以识别和跟踪运动技能发展中关键里程碑的神经学相关性。******我们将使用儿童友好的运动任务来获得高分辨率的MEG运动源成像，并结合MRI运动路径图，直接验证运动技能随着年龄的增长而成熟（例如，灵巧性的提高）将伴随着CM神经元在熟练运动控制过程中的激活转变的假设。重要的是，我们将在不同发育阶段的个体儿童中纵向跟踪这些变化，提供典型和延迟运动发育的神经生理指标。我们还将使用这些信息来指导所涉及的皮质运动网络的计算建模，这些网络可以预测观察到的脑电活动变化，以测试和验证这些网络中发育变化的生理模型。我们的研究将首次结合功能性脑磁图测量，以及对同一组儿童的一般和精细运动功能的详细评估，来检查关键年龄段的大脑结构变化。这将为典型发育儿童运动能力的产后发展提供一个新的视角，为更好地理解儿童早期典型和非典型运动技能的发展奠定基础。***********

The acquisition of skilled motor abilities is one of the most important aspects of human development. However, fine motor control and coordination does not approach adult patterns of stability until after the preschool years, a period when many motor disorders also emerge. Little is known about the underlying neural development of motor control, although it is known that both brain structure and function undergo dramatic changes throughout early childhood. Using Magnetoencephalography (MEG) functional measures in preschool children, we have recently demonstrated that movement-related brain activity does not demonstrate adult-like patterns until after preschool age. Studies in non-human primates have demonstrated that the motor cortex and its associated efferent pathways undergo significant changes in neural organization postnatally. This includes the delayed maturation of phylogenetically newer motor pathways originating in posterior motor cortex with direct connections to spinal motor neurons the corticomotoneuronal (CM) pathways which are critical for fine motor control such as dexterous hand movements. This suggests that the maturation of this motor system also occurs late in human development, yet such changes have never been directly measured, nor is their impact on normal motor development known. In the proposed research, we will combine for the first time, non-invasive neuroimaging techniques (functional MEG and structural MRI) with kinematic measures of fine motor skill assessments in typically developing children from ages 6 to 10 years to identify and track neurological correlates of critical milestones in motor skill development. ******We will use child-friendly motor tasks to obtain high-resolution MEG motor source imaging, combined with MRI tractography of motor pathways, to directly test the hypothesis that the maturation of motor skills with age (e.g., improved dexterity) will be accompanied by a shift to activation of CM neurons during the control of skilled movements. Importantly, we will track these changes longitudinally within individual children at different stages of development, providing neurophysiological indicators of both typical and delayed motor development. We will also use this information to guide computational modeling of the involved cortical motor networks that can predict the observed changes in electrical brain activity to test and validate physiological models of developmental changes in these networks. Our study will be the first to examine structural brain changes over a critical age period in combination with functional MEG measures, and detailed assessments of general and fine motor function in the same group of children. This will provide a new perspective on the postnatal development of motor abilities in typically developing children, laying the groundwork for a better understanding of both typical and atypical motor skill development during early childhood.***********