The Human Motor Output Map

项目摘要/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 有关电机命令结构的信息。值得注意的是，这些信息在人类中是可以访问的， 因为运动神经元的棘波和它们的肌肉纤维是1：1。我们的总体理念是 运动神经元的放电模式在人体肌肉中有系统地变化，这种变化 反映了运动指令的突触组织、 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，创建详细的人体运动输出图。该阵列 电极被放置在皮肤上，能够测量多达30个发动机单元的发射模式 同时在下面的肌肉中。我们计划进一步开发这些阵列的技术，以扩大 它们可用于各种运动任务。人体运动输出图将从以下分析中创建 在匹配的运动任务中，全身肌肉中的运动单位群体的放电模式。我们会 根据我们在理解放电模式方面的最新进展来解释结果图 运动神经元是由它们的突触输入的组织决定的。兴奋性和刺激性 对放电模式的抑制性输入是产生放电模式的基础，但神经调制输入 来自脑干的信息即使不是更重要也同样重要。这些神经调节输入释放5-羟色胺和 去甲肾上腺素，对运动神经元的内在兴奋性有深刻的影响，从而控制 运动神经元如何处理它们的兴奋性和抑制性输入。在目标1中，我们创建基本版本的 通过要求受试者产生缓慢的线性增加和减少的扭矩来绘制人类运动输出图 全身20多块肌肉。肌肉之间的协议保持完全相同，以允许 对所产生的发射模式进行比较。我们的主要假设是，参与稳定的肌肉 身体，如近端的肌肉，将产生与高水平的 神经调节驱动，而肌肉更多地参与精确任务将产生与 神经调节水平低。这些实验本质上是功能解剖学，近端-远端 放电模式的变化可能是由于突触输入到 汽车共用车。在目标2中，我们评估在激发模式中是否存在任务相关的变化，例如 神经调节的增加随着努力的增加而驱动，感觉抑制随着运动的增加而增加。 综上所述，这些实验将定义人类运动输出的基本结构 肌肉骨骼结构，并提供一个定量的基础，以了解扭曲发生在 疾病状态，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.