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 完全脊柱横断后。这些网络过程 来自身体表面特定部位的皮肤信息并生成 适当的运动节律，例如，响应于 刺激中部部位和抓口袋以响应 刺激臀部前面的部位。我们测试这个概念 一些参与喙突生成的脊髓神经元 左后肢的抓挠也参与右后肢的抓挠。 此外，我们还测试了一些额外的概念，即其中一些神经元 参与头端和口袋抓挠的产生 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“半中心”的延伸 假设。 “双边共享核心”假设将使用两种不同的方法进行检验 实验策略。一、左后肢脊椎龟 切除的增大物将用于检查吻端划痕的产生。 这种准备在右髋屈肌中产生虚构的运动节律 对右侧头侧划痕感受区的刺激的反应 右髋伸肌对左吻端刺激的反应 刮擦感受野。这种对特定节奏的控制是一种强大的 检查双边共享核心预测的实验工具 喙抓的假设。我们将记录轴突活动 虚构的抓挠过程中单个连合中间神经元被激活 左侧和右侧头侧划痕感受野刺激；我们 预测一些连合中间神经元也会被左侧激活 作为右头侧划痕感受野刺激。我们将表征 双边共享核心内的突触机制。二、脊柱 后肢增大完整的乌龟将用于检查左侧 和右后肢运动节律。肢体间阶段将在期间测量 对称的相同形式的行为，例如双侧喙部抓挠和 双边口袋抓挠，以及混合形式的行为，例如 结合同侧头端抓挠和对侧袋 抓挠。这些情况中的每一个都显示左手的异相协调 以及抓挠动作和虚构动作期间的右髋部运动输出 抓挠。这些结果支持了肢体间阶段控制的概念 在头端和口袋抓挠过程中，都是由双边共享的介导的 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元机制的信息 负责脊髓中的皮肤感觉运动整合。在 特别是，我们将揭示脊柱控制的重要特征 参与协调节律性运动输出产生的中枢。 乌龟脊髓与其他脊椎动物相似，包括 人类。我们揭示的机制可作为研究的工作假设 其他脊椎动物的脊髓感觉运动整合。