The Human Motor Output Map

项目总结/摘要 所有的运动输出都是由运动神经元产生的，因此它们的放电模式包含详细的 关于运动指令结构的信息。值得注意的是，这些信息在人类中是可以获得的， 因为运动神经元的峰电位与肌肉纤维的峰电位是1比1。我们的总体概念是， 运动神经元的放电模式在人体的肌肉中系统地变化， 反映了运动指令的突触组织之间的基本联系， 肌肉骨骼系统和运动任务的多样性。为了理解这些联系，我们的总体目标是 使用新开发的阵列电极创建人体的详细“电机输出图”。阵列 电极被放置在皮肤上，能够测量多达30个运动单元的放电模式 同时在肌肉中。我们计划对这些阵列进行进一步的技术开发， 一系列的运动任务，他们可以使用。人类运动输出图将通过分析 全身肌肉中运动单位群体的放电模式，用于匹配运动任务。我们将 根据我们最近在理解大脑的放电模式方面的进展， 运动神经元由它们的突触输入的组织决定。兴奋性和 对放电模式的抑制性输入是产生放电模式的基础，但神经调节性输入 都是同等重要的这些神经调节输入释放血清素， 去甲肾上腺素，其对运动神经元的内在兴奋性具有深远的影响，从而控制 运动神经元如何处理兴奋性和抑制性输入。在目标1中，我们创建了 通过要求受试者产生扭矩的缓慢线性增加和减少来绘制人类运动输出图， 全身有20多块肌肉协议在肌肉之间保持完全相同， 比较所产生的发射模式。我们的主要假设是，肌肉参与稳定的 身体（例如近端肌肉）将产生与高水平的运动神经元放电相一致的运动单元放电模式， 神经调节驱动，而肌肉参与更多的精确任务将产生模式一致， 低水平的神经调节这些实验基本上是功能解剖学， 放电模式的变化可能源于突触输入的解剖投射的差异， 车辆调配场在目标2中，我们评估是否有任务相关的变化，如放电模式， 随着努力的增加，神经调节驱动增加，随着运动，感觉抑制增加。 综合起来，这些实验将确定人类运动输出的基本结构 肌肉骨骼结构，并提供定量基础，了解发生的扭曲， 比如脊髓损伤

PROJECT SUMMARY/ABSTRACT All motor output is generated by motoneurons and consequently their firing patterns contain detailed information about the structure of motor commands. Remarkably, this information is accessible in humans, because motoneuron spikes are 1 to 1 with those of their muscle fibers. Our overall concept is that motoneuronal firing patterns vary systematically across the muscles of the human body and that this variation reflects fundamental connections between the synaptic organization of motor commands, the structure of the musculoskeletal system and the diversity of motor tasks. To understand these connections, our overall goal is to create a detailed “motor output map” of the human body, using newly developed array electrodes. The array electrodes are placed on the skin and are capable of measuring the firing patterns of up to 30 motor units simultaneously in the underlying muscle. We plan further technical development of these arrays to expand the range of motor tasks they can be used for. The human motor output map will be created from the analysis of firing patterns of populations of motor units in muscles throughout the body for matched motor tasks. We will interpret the resulting map in light of our recent advances in understanding of how firing patterns of motoneurons are determined by the organization of their synaptic inputs. The effects of excitatory and inhibitory inputs on firing patterns are fundamental for generating firing patterns, but neuromodulatory inputs from the brainstem are equally if not more important. These neuromodulatory inputs release serotonin and norepinephrine, which have a profound influence on the intrinsic excitability of motoneurons and thus control how motoneurons process their excitatory and inhibitory inputs. In Aim 1, we create a basic version of the human motor output map by asking subjects to generate slow linear increases and decreases in torque for more than 20 muscles across the body. The protocol is kept exactly the same across muscles to allow comparisons of the resulting firing patterns. Our primary hypothesis is that muscles involved in stabilization of the body, such as proximal muscles, will generate motor unit firing patterns consistent with high levels of neuromodulatory drive, while muscles involved more in precision tasks will generate patterns consistent with low levels of neuromodulation. These experiments are essentially function anatomy, the proximal-distal variations in firing patterns probably arise from differences in the anatomical projections of synaptic inputs to motor pools. In Aim 2, we assess whether there are task dependent changes in firing patterns, such as increases in neuromodulation drive with increased effort and increases in sensory inhibition with movement. Taken together, these experiments will define the fundamental structure of motor output for the human musculoskeletal structure and provide a quantitative basis for understanding the distortions that occur in disease states like spinal cord injury.