Afferent control of locomotor CPG: insights from a simple neuromechanical model
Afferent control of locomotor CPG: insights from a simple neuromechanical model
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DOI：
10.1111/j.1749-6632.2010.05435.x
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发表时间：
2010-01-01
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影响因子：
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通讯作者：
Rybak, Ilya A.
中科院分区：
文献类型：
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作者：
Markin, Sergey N.;Klishko, Alexander N.;Rybak, Ilya A.
一个简单的神经力学模型已被开发，描述了一个脊髓中央模式发生器（CPG）控制的自发运动的单关节肢体通过激活两个拮抗肌（屈肌和伸肌）。肢体在肌肉、重力和地面反作用力的控制下进行有节奏的运动。肌肉传入神经向CPG提供长度依赖性（Ia型和II型）和力依赖性（来自伸肌的Ib型）反馈。我们发现，传入反馈调节CPG操作的运动学和动力学的肢体提供稳定的“运动”。“增加对CPG的脊髓上驱动通过减少站立阶段的持续时间来增加运动速度。我们发现，这种不对称的，伸肌主导的控制运动速度（相对恒定的摆动持续时间）是由传入反馈独立的CPG单独产生的不对称的节奏模式（在“虚构的运动”条件）。最后，我们证明了恢复稳定的运动后，去除脊髓上的驱动器（与脊髓损伤），通过增加传入输入的CPG，这被认为是发生运动训练的重量的可能性。
A simple neuromechanical model has been developed that describes a spinal central pattern generator (CPG) controlling the locomotor movement of a single-joint limb via activation of two antagonist (flexor and extensor) muscles. The limb performs rhythmic movements under control of the muscular, gravitational and ground reaction forces. Muscle afferents provide length-dependent (types Ia and II) and force-dependent (type Ib from the extensor) feedback to the CPG. We show that afferent feedback adjusts CPG operation to the kinematics and dynamics of the limb providing stable "locomotion." Increasing the supraspinal drive to the CPG increases locomotion speed by reducing the duration of stance phase. We show that such asymmetric, extensor-dominated control of locomotor speed (with relatively constant swing duration) is provided by afferent feedback independent of the asymmetric rhythmic pattern generated by the CPG alone (in "fictive locomotion" conditions). Finally, we demonstrate the possibility of reestablishing stable locomotion after removal of the supraspinal drive (associated with spinal cord injury) by increasing the weights of afferent inputs to the CPG, which is thought to occur following locomotor training.