SENSORY AND MOTOR INTEGRATION IN THE SPINAL CORD

脊髓中的感觉和运动整合

• 批准号: 6139497
• 负责人: Paul S. Stein
• 金额: $ 20.08万
• 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/6139497
• 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.

有肢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激活之间的交替 屈肌和髋伸肌运动神经元。我们研究脊髓中的这些节律 脊髓完全横断的乌龟 前肢增大。我们检查负责的脊髓回路 抓挠的 3 种运动策略（“形式”）的产生（吻侧、 口袋式、尾式）和 2 种游泳方式（向前游泳、向后划桨）。我们 检验“双侧核心撕裂”假说：脊髓回路 参与后肢特定节律行为的产生 双边分配并负责生产更多 而不是一种有节奏的行为。 我们开发了一种前横半切的脊柱准备 后肢增大，产生髋部屈肌节律 缺乏响应同侧刺激的髋部伸肌活动 在中体吻侧划痕感受野（J Neurosci 18：467-479， 1998）。这表明髋部屈肌回路可以在以下情况下产生节律： 缺乏髋部伸肌回路激活。这个准备也 产生“重建”的正常臀部抓挠 屈肌/伸肌节律交替响应 2 部位刺激 完整侧吻侧划痕感受野中有一个位点， 另一个位点在另一个划痕接受域中。这些实验支持 划痕的 3 种形式的双边共享核心假设。 我们提出了研究脊髓抓挠运动模式的实验 具有横向半切的固定龟。我们分析一下这个电机 模式以及运动神经元和活动模式中的突触驱动 下降的本体脊髓中间神经元。我们测试具体的预测 双边共享核心假设，例如，我们检查突触后 抓挠运动过程中对侧髋关节运动神经元的电位 对同侧抓挠中的触觉刺激做出反应的节律 感受野。 我们还提出了研究抓挠和游泳的实验 脊椎龟有运动。我们测量肌肉活动模式并 后肢运动学。我们测试双边共享核心的版本 假设指出产生刮擦节奏的神经元件 也产生游泳节奏。 龟脊髓与其他脊椎动物相似，包括 人类。我们在海龟身上揭示的脊柱机制起到了作用 研究其他脊椎动物运动节律产生的假设， 包括人类。