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）：电动机皮质使用哪种语言与运动神经元说话？主电机皮层（M1）是脊髓下降命令的主要来源，以产生电动机输出。额叶的皮质脊髓神经元中约有50％起源于M1。这些皮质脊髓神经元的特殊集是与运动神经元直接连接的皮质骨术（CM细胞）。我们将使用行为，电生理和解剖学方法的组合研究CM细胞。我们提议首次提供从CM细胞到运动神经元的信号传导的清晰而一致的视图。我们将使用施肌电（EMG）活性的尖峰触发平均（SPTA）鉴定CM细胞及其目标肌肉。 CM细胞及其目标肌肉的活性将与涉及的手腕运动有关，该运动涉及能够分离手腕运动的固有（肌肉样）和外在的（运动状）参数的多向腕部任务。先前的研究表明，M1活性中存在固有和外在参数（Kakei等，1999）。解释“肌肉”和“运动”的存在的一种方法是层次结构的存在。层次结构假设将预测CM细胞活性是肌肉，而非CM细胞活性则像运动一样。换句话说，对运动神经元的直接输入是一种不需要翻译的语言。另一种选择是，肌肉样和运动样活动的混合物到达运动神经元，用于在不同条件下创建运动。该项目将确定哪些假设是正确的。我们还将首次记录投影到手腕肌肉动物神经元的CM细胞的位置和分布。我们将使用狂犬病病毒的跨神经元转运来定义CM细胞在运动皮层中影响拮抗腕部肌肉的位置。屈肌radial骨和伸肌radialis。如果时间允许，我们将比较幼稚动物中CM细胞的分布与受过训练的动物的熟练手腕任务的分布。该实验将使我们能够确定广泛的训练是否会改变M1中CM细胞的皮质领域。