SENSORY AND MOTOR INTEGRATION IN THE SPINAL CORD

脊髓中的感觉和运动整合

• 批准号: 2757959
• 负责人: Paul S. Stein
• 金额: $ 19.5万
• 依托单位: WASHINGTON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1992
• 资助国家: 美国
• 起止时间: 1992-07-01 至 2002-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2757959
• 关键词: Chelonia; chordate locomotion; electrical measurement; electromyography; electrophysiology; immobilization of body part; interneurons; motor neurons; neural transmission; neuromuscular function; sensorimotor system; sensory feedback; spinal cord; spinal cord mapping; spinal nerves; spinal reflex

Neuronal networks in the spinal cord of limbed vertebrates generate motor rhythms that usually include alternation between activation of hip flexor and hip extensor motoneurons. We study these rhythms in a spinal turtle with complete spinal cord transection just posterior to the forelimb enlargement. We examine spinal cord circuitry responsible for the production of 3 motor strategies, "forms", of scratching (rostral, pocket, caudal) and 2 forms of swimming (forward swim, backpaddle). We test the "bilateral shred core" hypothesis: spinal cord circuitry involved in the production of a specific rhythmic behavior in a hindlimb is bilaterally distributed and is responsible for the production of more than one rhythmic behavior. We developed a spinal preparation with transverse hemisection anterior to the hindlimb enlargement that produces hip flexor rhythms in the absence of hip extensor activity in response to ipsilateral stimulation in the mid-body rostral scratch receptive field (J Neurosci 18:467-479, 1998). This establishes that hip flexor circuits can be rhythmogenic in the absence of hip extensor circuit activation. This preparation also generates "reconstructed" normal rostral scratching with hip flexor/extensor rhythmic alternation in response to 2-site stimulation with one site in the intact-side rostral scratch receptive field and the other site in another scratch receptive field. These experiments support the bilateral shared core hypothesis for the 3 forms of the scratch. We propose experiments that study scratch motor patterns in the spinal immobilized turtle with transverse hemisection. We analyze this motor patterns along with synaptic drive in motoneurons and activity patterns of descending propriospinal interneurons. We test specific predictions of the bilateral shared core hypothesis, e.g., we examine post-synaptic potentials in contralateral hip motoneurons during scratching motor rhythms in response to tactile stimulation in an ipsilateral scratch receptive field. We also propose experiments that study scratching and swimming in a spinal turtle with movement. We measure muscle activity patterns and hindlimb kinematics. We test a version of the bilateral shared core hypothesis stating that neural elements that produce scratch rhythms also produce swim rhythms. Turtle spinal cord is similar to that of other vertebrates, including humans. The spinal mechanisms that we reveal in turtle serve as working hypotheses for studies of motor rhythm generation in other vertebrates, including humans.

肢体脊椎动物脊髓中的神经元网络产生 运动节律，通常包括髋关节活动之间的交替 屈肌和髋伸肌运动神经元。我们在脊椎上研究这些节律 脊椎后方有完整脊髓横断的海龟 前肢放大。我们检查负责脊髓回路的 3种运动策略的产生，“形式”，抓挠(吻部， 游泳有两种形式(向前游、背板游)。我们 检验“双侧碎核”假说：脊髓回路 与后肢特定节奏行为的产生有关的 是双边分配的，并负责生产更多 而不是一种有节奏的行为。 我们开发了一种具有前半横断的脊柱准备 后肢增大会产生髋屈肌的节律 对同侧刺激的反应缺乏髋关节伸展活动 在中体吻部抓挠感受区(J Neurosci 18：467-479， 1998年)。这建立了髋屈肌回路可以是节律性的 缺乏髋关节伸肌回路的激活。这一准备工作也 用臀部产生“重建”的正常唇部抓痕 双部位刺激对屈伸肌节律性交替的影响 其中一个部位在完整侧吻部抓挠接受野，而 其他站点在另一个刮擦接受场。这些实验支持 关于划痕的三种形式的双边共享核心假说。 我们建议进行实验，研究脊椎的抓挠运动模式。 横切半横断的固定乌龟。我们分析了这台马达 运动神经元中的模式以及突触驱动和活动模式 下降的固有脊髓中间神经元。我们测试特定的预测 例如，我们检查突触后 抓挠运动时对侧髋部运动神经元的电位 同侧抓挠对触觉刺激的反应节律 接受野。 我们还提出了研究抓挠和游泳的实验 会移动的脊椎龟。我们测量肌肉活动模式和 后肢运动学。我们测试双边共享核心的一个版本 假说认为产生抓挠节律的神经元素 也会产生游泳节奏。 海龟的脊髓与其他脊椎动物的脊髓相似，包括 人类。我们在海龟身上揭示的脊椎机制是起作用的 其他脊椎动物运动节律产生研究的假说， 包括人类。