Control of stepping velocity in a single insect leg during walking
Control of stepping velocity in a single insect leg during walking
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DOI：
10.1098/rsta.2006.1912
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发表时间：
2007-01-15
期刊：
影响因子：
5
通讯作者：
Bueschges, Ansgar
中科院分区：
文献类型：
--
作者：
Gabriel, Jens Peter;Bueschges, Ansgar
在竹节虫在跑步机上行走的单中腿准备中，研究了分别负责站立和摆动阶段胫骨运动的屈肌和伸肌运动神经元和肌肉的活动随行走速度的变化。步进速度的变化与周期有关。屈肌运动神经元的活动（站立期）与步速密切相关，而伸肌运动神经元的活动（摆动期）与步速无关。屈肌运动神经元的去极化表现为两个组成部分。在所有步进速度下，在姿态相活动开始时都产生了一个立体的初始去极化。随后更大的去极化和激活与带速度密切相关，即与慢步相比，快步发生的时间更早，幅度更大。紧张性背景兴奋的改变似乎在控制步进速度变化的运动神经元活动中不起作用。我们的研究结果表明，在单个昆虫腿行走过程中，改变步速的机制仅在已经进行的姿态相位电机输出中有效。我们讨论了所涉及的假定机制。
In the single middle leg preparation of the stick insect walking on a treadmill, the activity of flexor and extensor tibiae motor neurons and muscles, which are responsible for the movement of the tibia in stance and swing phases, respectively, was investigated with respect to changes in stepping velocity. Changes in stepping velocity were correlated with cycle period. There was a close correlation of flexor motor neuron activity (stance phase) with stepping velocity, but the duration and activation of extensor motor neurons (swing phase) was not altered. The depolarization of flexor motor neurons showed two components. At all step velocities, a stereotypic initial depolarization was generated at the beginning of stance phase activity. A subsequent larger depolarization and activation was tightly linked to belt velocity, i.e. it occurred earlier and with larger amplitude during fast steps compared with slow steps. Alterations in a tonic background excitation appear not to play a role in controlling the motor neuron activity for changes in stepping velocity. Our results indicate that in the single insect leg during walking, mechanisms for altering stepping velocity become effective only during an already ongoing stance phase motor output. We discuss the putative mechanisms involved.