SENSORY AND MOTOR INTEGRATION IN THE SPINAL CORD

神经网络在甲鱼脊髓产生抓挠反射 在一次完整的脊椎横断后。这些网络进程 来自身体表面特定部位的皮肤信息，并产生 适当的运动节律，例如，对以下反应的吻部抓挠 刺激中身部位和口袋抓挠的反应 对臀部前方部位的刺激。我们测试了这样一个概念 一些参与吻部发生的脊髓神经元 抓挠左后肢也参与了右后肢抓挠。 此外，我们测试了另一个概念，即这些神经元中的一些 参与生成鸡冠和口袋抓挠 左后肢和右后肢都有。这些“双边共享核心” 我们检验的假设是经典的“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测试 实验策略。首先，有左后肢的脊甲鱼 去除的放大将用于检查吻部划痕的产生。 这种准备在右髋屈肌中产生假想的运动节律 右侧嘴侧抓挠感受区对刺激的反应 右侧髋关节伸肌对左侧吻部刺激的反应 刮擦感受野。这种对特定节奏的控制是一种强大的 检验双边共享核心预测的实验工具 吻部抓挠假说。我们将记录大鼠的轴突活动 在假想抓挠时激活单个连合中间神经元 左侧和右侧吻部抓挠感受场刺激； 预测一些连合中间神经元也被左脑激活 如右侧嘴侧抓挠感受场刺激。我们将描述 双侧共用核内的突触机制。第二，脊椎 后肢完整增大的海龟将被用来检查左侧 以及右后肢运动节律。肢体间位相将在 对称的相同形式的行为，如双侧吻部抓挠和 双侧口袋抓挠，以及在混合形式行为期间，如 作为同侧吻部抓挠和对侧眼袋的组合 在抓挠。这些情况中的每一个都显示左侧的异相协调 以及在抓挠动作和虚构动作中的右髋部运动输出 在抓挠。这些结果支持肢体间相位控制的概念 在嘴部和口袋的抓挠都是通过双边共享进行调节的 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机制的信息。 负责脊髓内皮肤感觉运动的整合。在……里面 特别是，我们将揭示脊椎控制的重要特征 参与产生协调的有节奏的运动输出的中枢。 海龟的脊髓与其他脊椎动物的脊髓相似，包括 人类。我们揭示的机制可以作为研究的工作假设。 其他脊椎动物的脊髓感觉运动整合。

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.