What language does the motor cortex use to speak to motoneurons?

运动皮层使用什么语言与运动神经元对话？

• 批准号: 8476282
• 负责人: Darcy M. Griffin
• 金额: $ 5.57万
• 依托单位: UNIVERSITY OF PITTSBURGH AT PITTSBURGH
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-07-01 至 2014-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8476282
• 关键词: Agonist; Animals; Avidin; Behavioral; Biotin; Brain Stem; Cell Nucleus; Cells; Data; Elbow; Fingers; Flexor; Hand; Histology; Human; Injection of therapeutic agent; Interneurons; Label; Language; Lead; Learning; Location; Macaca mulatta; Maps; Methods; Monkeys; Motor; Motor Cortex; Motor Neurons; Motor Skills; Motor output; Movement; Muscle; Muscle Cells; Nature; Neurons; Output; Peroxidases; Play; Pongidae; Population; Positioning Attribute; Property; Rabies virus; Shoulder; Signal Transduction; Slice; Source; Spinal; Spinal Cord; Staining method; Techniques; Time; Training; Translating; Wrist; brain surgery; frontal lobe; kinematics; motor skill learning; research study; skills; tool

DESCRIPTION (provided by applicant): What language does the motor cortex use to speak to motoneurons? The primary motor cortex (M1) is a major source of descending commands to the spinal cord for generating motor output. Approximately 50% of the corticospinal neurons from the frontal lobe originate from M1. A special set of these corticospinal neurons are corticomotoneural (CM cells) which have direct connections to motoneurons. We will investigate CM cells using a combination of behavioral, electrophysiological and anatomical methods. We propose to provide, for the first time, a clear and consistent view of signaling from CM cells to motoneurons. We will identify CM cells and their target muscles using spike-triggered averaging (SpTA) of electromyographic (EMG) activity. The activity of CM cells and their target muscles will be investigated in relation to wrist movements involved in a multi-directional wrist task capable of dissociating intrinsic (muscle-like) and extrinsic (movement-like) parameters of wrist movement. Previous studies have shown that both intrinsic and extrinsic parameters are present in M1 activity (Kakei et al., 1999). One way to explain the presence of both "muscles" and "movements" is the existence of a hierarchy. The hierarchy hypothesis would predict that CM cell activity is muscle like and non-CM cell activity is movement like. In other words, direct input to motoneurons is in a language that does not need to be translated. The alternative is that a mixture of muscle-like and movement-like activity reaches the motoneuron and is used to create movements under different conditions. This project will determine which hypothesis is correct. We will also document, for the first time, the location and distribution of CM cells projecting to wrist muscle motoneurons. We will use the transneuronal transport of rabies virus to define the location of CM cells in the motor cortex that influence antagonist wrist muscles; flexor carpi radialis and extensor carpi radialis. If time permits, we will compare the distribution of CM cells in naive animals to those of animals trained to perform a skilled wrist task. This experiment will enable us to determine whether extensive training alters the cortical territory of CM cells in M1.

描述（由申请人提供）：运动皮层使用什么语言与运动神经元对话？初级运动皮层 (M1) 是向脊髓发出下行命令以产生运动输出的主要来源。额叶皮质脊髓神经元中大约 50% 起源于 M1。一组特殊的皮质脊髓神经元是皮质运动神经元（CM 细胞），它们与运动神经元有直接连接。我们将结合行为学、电生理学和解剖学方法来研究 CM 细胞。我们建议首次提供从 CM 细胞到运动神经元的信号传导的清晰一致的视图。我们将使用肌电图 (EMG) 活动的尖峰触发平均 (SpTA) 来识别 CM 细胞及其目标肌肉。将研究 CM 细胞及其目标肌肉的活动与多向手腕任务中涉及的手腕运动的关系，该任务能够分离手腕运动的内在（类肌肉）和外在（类运动）参数。先前的研究表明，M1 活性中存在内在和外在参数（Kakei 等人，1999）。解释“肌肉”和“运动”两者存在的一种方法是层次结构的存在。层次假设将预测 CM 细胞活动类似于肌肉，而非 CM 细胞活动类似于运动。换句话说，运动神经元的直接输入是不需要翻译的语言。另一种方法是，类似肌肉和类似运动的活动的混合到达运动神经元，并用于在不同条件下产生运动。该项目将确定哪种假设是正确的。我们还将首次记录投射到腕部肌肉运动神经元的 CM 细胞的位置和分布。我们将利用狂犬病病毒的跨神经元转运来确定运动皮层中影响拮抗腕肌的 CM 细胞的位置；桡侧腕屈肌和桡侧腕伸肌。如果时间允许，我们将比较幼稚动物和经过训练以执行熟练手腕任务的动物的 CM 细胞分布。该实验将使我们能够确定大量训练是否会改变 M1 中 CM 细胞的皮质区域。