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.

神经元网络在乌龟脊髓中产生划痕反射 在完整的脊柱横切后。这些网络处理 来自身体表面的特定部位的皮肤信息并产生 适当的电动节奏，例如，响应于和 刺激中体部位和袖珍刮擦 仅在臀部前方刺激部位。我们测试了一个概念 一些参与Rostral产生的脊柱神经元 左后肢的抓挠也参加了右后肢。 此外，我们测试了其中一些神经元的其他概念 参与产生的Rostral和Pocket刮擦 左侧和右后肢。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 假设。 将使用两种不同的假设进行“双边共享核心”假设 实验策略。首先，带有左后肢的脊柱龟 删除扩大将用于检查鼻刮擦的产生。 此准备在右髋屈肌中产生虚拟的运动节奏 对右侧刮擦感受场刺激的响应和 在右髋关节伸肌中响应左侧刺激的刺激 刮擦接收场。对特定节奏的这种控制是一种强大的 实验工具检查双边共享核心的预测 鼻刮的假设。我们将记录轴突活动 虚拟刮擦中的单个连合中神经元被激活 左侧和右鼻刮擦感受场刺激；我们 预测某些连合中间神经元也被左激活 作为右鼻刮擦接受场刺激。我们将表征 双边共享核心内的突触机制。第二，脊柱 具有完整后肢扩大的乌龟将用于检查左 和右后肢运动节奏。跨阶段将在 对称相同形式的行为，例如双边鼻刮擦和 双边袋刮擦以及混合形式行为期间 作为同侧鼻刮和对侧袋的组合 刮擦。这些案例中的每一个都显示左侧的相位协调 以及在刮擦运动和虚构期间右髋关节电动机输出 刮擦。这些结果支持了跨越阶段控制的概念 在鼻子和袖珍刮擦期间，双边共享介导 与髋关节控制有关的核心连合中神经元。 我们的实验提供了有关神经元机制的信息 负责脊髓中皮肤的感觉运动积分。在 特别是，我们将揭示脊柱控制的重要特征 参与协调节奏的运动输出的中心。 乌龟脊髓与其他脊椎动物相似，包括 人类。我们揭示的机制是研究的工作假设 其他脊髓的脊髓感觉运动积分