Fujiki Soichiro, Aoi Shinya, Tsuchiya Kazuo, Danner Simon M, Rybak Ilya A, Yanagihara Dai
Department of Physiology and Biological Information, Dokkyo Medical University School of Medicine, Mibu, Japan.
Department of Aeronautics and Astronautics, Graduate School of Engineering, Kyoto University, Kyoto, Japan.
Front Neurosci. 2019 Nov 29;13:1288. doi: 10.3389/fnins.2019.01288. eCollection 2019.
Central pattern generators (CPGs) in the spinal cord generate rhythmic neural activity and control locomotion in vertebrates. These CPGs operate under the control of sensory feedback that affects the generated locomotor pattern and adapt it to the animal's biomechanics and environment. Studies of the effects of afferent stimulation on fictive locomotion in immobilized cats have shown that brief stimulation of peripheral nerves can reset the ongoing locomotor rhythm. Depending on the phase of stimulation and the stimulated nerve, the applied stimulation can either shorten or prolong the current locomotor phase and the locomotor cycle. Here, we used a mathematical model of a half-center CPG to investigate the phase-dependent effects of brief stimulation applied to CPG on the CPG-generated locomotor oscillations. The CPG in the model consisted of two half-centers mutually inhibiting each other. The rhythmic activity in each half-center was based on a slowly inactivating, persistent sodium current. Brief stimulation was applied to CPG half-centers in different phases of the locomotor cycle to produce phase-dependent changes in CPG activity. The model reproduced several results from experiments on the effect of afferent stimulation of fictive locomotion in cats. The mechanisms of locomotor rhythm resetting under different conditions were analyzed using dynamic systems theory methods.
脊髓中的中枢模式发生器（CPG）产生有节律的神经活动，并控制脊椎动物的运动。这些CPG在感觉反馈的控制下运作，感觉反馈会影响所产生的运动模式，并使其适应动物的生物力学和环境。对传入刺激对固定猫的虚拟运动的影响的研究表明，短暂刺激外周神经可以重置正在进行的运动节律。根据刺激的阶段和受刺激的神经，施加的刺激可以缩短或延长当前的运动阶段和运动周期。在这里，我们使用一个半中枢CPG的数学模型来研究对CPG施加短暂刺激对CPG产生的运动振荡的相位依赖性影响。模型中的CPG由两个相互抑制的半中枢组成。每个半中枢中的节律性活动基于一种缓慢失活的持续性钠电流。在运动周期的不同阶段对CPG半中枢施加短暂刺激，以产生CPG活动的相位依赖性变化。该模型重现了关于猫的虚拟运动的传入刺激效果的几个实验结果。使用动态系统理论方法分析了不同条件下运动节律重置的机制。
