SENSORY AND MOTOR INTEGRATION IN THE SPINAL CORD

脊髓中的感觉和运动整合

• 批准号: 2519949
• 负责人: Paul S. Stein
• 金额: $ 19.42万
• 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 1998-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2519949
• 关键词: Chelonia; chordate locomotion; electrophysiology; motor neurons; neural information processing; neuromuscular function; sensory feedback; single cell analysis; spinal cord; spinal cord mapping; spinal cord surgery; spinal nerves; spinal reflex

Neuronal networks generate the scratch reflex in the turtle spinal cord posterior to a complete spinal transection. These networks process cutaneous information from specific sites on the body surface and generate appropriate motor rhythms, e.g., rostral scratching in response to stimulation of midbody sites and pocket scratching in response to stimulation of sites just anterior to the hip. We test the concept that some spinal neurons that participate in the generation of rostral scratching for the left hindlimb also participate for the right hindlimb. In addition, we test the additional concept that some of these neurons participate in the generation of both rostral and pocket scratching for both the left and the right hindlimbs. These "bilateral shared core" hypotheses that we test are an extension of the classical "half-center" hypothesis. "Bilateral shared core" hypotheses will be tested using two different experimental strategies. First, the spinal turtle with the left hindlimb enlargement removed will be used to examine rostral scratch generation. This preparation generates fictive motor rhythms in right hip flexors in response to stimulation in the right rostral scratch receptive field and in right hip extensors in response to stimulation in the left rostral scratch receptive field. This control over specific rhythms is a powerful experimental tool to examine predictions of the bilateral shared core hypothesis for rostral scratching. We will record axonal activities of single commissural interneurons during fictive scratching activated by left as well as right rostral scratch receptive field stimulation; we predict that some commissural interneurons are activated by left as well as right rostral scratch receptive field stimulation. We will characterize synaptic mechanisms within the bilateral shared core. Second, a spinal turtle with an intact hindlimb enlargement will be used to examine left and right hindlimb motor rhythms. Interlimb phase will be measured during symmetric same-form behaviors such as bilateral rostral scratching and bilateral pocket scratching, as well as during mixed-form behaviors such as combined ipsilateral rostral scratching and contralateral pocket scratching. Each of these cases displays out-of-phase coordination of left and right hip motor output during scratching movements and during fictive scratching. These results support the concept that interlimb phase control during both rostral and pocket scratching is mediated by bilateral shared core commissural interneurons related to hip control. Our experiments provide information concerning the neuronal mechanisms responsible for cutaneous sensorimotor integration in the spinal cord. In particular, we will reveal important characteristics of spinal control centers involved in the generation of coordinated rhythmic motor output. The turtle spinal cord is similar to that of other vertebrates, including humans. The mechanisms we reveal serve as working hypotheses for studies of spinal cord sensorimotor integration in other vertebrates.

神经元网络在海龟脊髓中产生抓挠反射 脊柱完全横断的后方这些网络处理 皮肤信息从身体表面上的特定部位，并生成 适当的运动节律，例如，吻侧搔抓反应 刺激的中体部位和口袋抓挠响应于 刺激髋关节前的部位。我们测试的概念， 一些脊髓神经元参与喙部神经元的生成， 对左后肢的抓挠也参与对右后肢的抓挠。 此外，我们还测试了一个额外的概念，即这些神经元中的一些 参与喙和口袋抓挠的产生， 左后肢和右后肢。这些“双边共享核心” 我们测试的假设是经典的“半中心”的扩展 假说. “双边共享核心”假设将使用两种不同的 实验策略。第一，左后肢的脊椎龟 移除的放大图像将用于检查嘴侧划痕的产生。 这种准备在右髋屈肌中产生虚构的运动节律， 对右吻侧抓挠感受野中的刺激的反应， 右髋伸肌对左喙肌刺激的反应 抓挠感受野这种对特定节奏的控制是一种强大的 检验双边共享核心预测的实验工具 喙部抓痕假说我们将记录轴突活动， 单个连合中间神经元在虚拟抓挠过程中被激活 左和右吻侧抓挠感受野刺激;我们 预测一些连合中间神经元也被左激活， 作为右吻侧抓挠感受野刺激。我们将描述 双侧共享核心内的突触机制。第二，脊柱 一只后肢膨大完整的海龟将被用来检查左 和右后肢运动节律。将在以下期间测量肢体间相位： 对称的相同形式的行为，如双侧喙抓， 双侧口袋抓挠，以及在混合形式的行为， 同侧嘴侧抓痕和对侧囊袋 抓挠这些情况中的每一个都显示了左心室的异相协调， 和右髋运动输出在抓挠运动和在虚构的 抓挠这些结果支持了臂间相位控制 在嘴侧和口袋抓挠期间， 与髋关节控制相关的核心连合中间神经元。 我们的实验提供了有关神经机制的信息 负责脊髓中的皮肤感觉运动整合。在 特别是，我们将揭示脊髓控制的重要特征， 参与协调的节律性运动输出的产生的中枢。 海龟的脊髓与其他脊椎动物相似，包括 人类我们揭示的机制作为研究的工作假设 脊髓感觉运动的整合。