SENSORY AND MOTOR INTEGRATION IN THE SPINAL CORD

四肢脊椎动物脊髓中的神经元网络 运动节律通常包括髋关节活动和髋关节活动之间的交替 屈肌和髋伸肌运动神经元。我们在脊髓中研究这些节律 脊髓完全横断的龟，就在 前肢增大我们检查脊髓回路， 产生3种运动策略，“形式”，抓挠（嘴侧， 口袋，尾）和2种形式的游泳（向前游泳，背桨）。我们 检验“双侧核心碎片”假说：脊髓回路 与后肢产生特定的节奏行为有关 是双边分布，并负责生产更多的 比一个有节奏的行为。 我们开发了一种脊柱前半横切术 后肢扩大，产生髋屈肌节奏， 对同侧刺激无髋伸肌活动 在身体中部的喙侧划痕感受野（JNeurosci 18：467-479， 1998年）。这表明，髋屈肌回路可以是节律性的， 没有髋关节伸肌回路激活。该制剂还 产生“重建的”正常喙部抓痕， 屈/伸肌对双部位刺激的节律性交替反应 一个位点在完整侧吻侧划痕感受野， 在另一个划痕感受野的其他部位。这些实验支持 3种划痕形式的双侧共享核心假说。 我们提出的实验，研究划痕运动模式在脊髓 横向半切的固定海龟。我们分析这个发动机 运动神经元突触驱动的沿着模式和活动模式 下行的固有脊髓中间神经元。我们测试特定的预测 双边共享核心假设，例如，我们检查突触后 抓挠运动时对侧髋关节运动神经元的电位 同侧抓挠对触觉刺激的反应节律 感受野 我们还提出了研究抓挠和游泳的实验， 会动的脊椎龟我们测量肌肉活动模式， 后肢运动学我们测试一个版本的双边共享核心 假设产生抓挠节奏的神经元 也会产生游泳的节奏。 海龟的脊髓与其他脊椎动物相似，包括 人类我们在海龟身上发现的脊椎机制 其他脊椎动物运动节律产生研究的假设， 包括人类

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.