Control of flexor motoneuron activity during single leg walking of the stick insect on an electronically controlled treadwheel
Control of flexor motoneuron activity during single leg walking of the stick insect on an electronically controlled treadwheel
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DOI：
10.1002/neu.10237
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发表时间：
2003-09-01
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影响因子：
--
通讯作者：
Büschges, A
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文献类型：
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作者：
Gabriel, JP;Scharstein, H;Büschges, A
在本研究中，运动神经元支配屈胫肌的竹节虫（Cuniculina impigra）中腿细胞内记录，而单腿进行步行样运动的车轮上。不同水平的皮带摩擦力（相当于负荷的变化）被用来研究屈肌运动神经元活动的控制。在缓慢的腿部运动没有快速运动神经元活跃，但这些神经元的招聘可以观察到在更快的腿部运动。慢速和快速运动神经元的放电率随着皮带摩擦力的增加而增加。此外，在不同的摩擦水平下施加到摩擦轮的力与要克服的摩擦轮的摩擦紧密地相适应。支配屈肌胫前肌的运动神经元在站立阶段逐渐被募集，慢运动神经元比快运动神经元更早被激活（半最大峰频率分别在站立阶段的10-15%和50-60%之后）。快运动神经元的静息膜电位（64.6 +/- 6.5 mV）比慢运动神经元（-52.9 +/- 5.4 mV）更高。然而，两种类型的屈肌运动神经元的动作电位的起始阈值在统计学上没有显著差异。因此，动作电位产生于快速运动神经元经过较长时间的去极化，因此在立场阶段比在缓慢的运动神经元。我们发现，屈肌tidrons收到大量共同的兴奋性输入的立场阶段，慢和快运动神经元之间的静息膜电位的差异很可能在其连续招聘中发挥至关重要的作用。(C)2003 Wiley Periodicals，Inc.
In the present study, motoneurons innervating the flexor tibiae muscle of the stick insect (Cuniculina impigra) middle leg were recorded intracellularly while the single leg performed walking-like movements on a treadwheel. Different levels of belt friction (equivalent to a change in load) were used to study the control of activity of flexor motoneurons. During slow leg movements no fast motoneurons were active, but a recruitment of these neurons could be observed during faster leg movements. The firing rate of slow and fast motoneurons increased with incremented belt friction. Also, the force applied to the treadwheel at different frictional levels was adapted closely to the friction of the treadwheel to be overcome. The motoneurons innervating the flexor tibiae were recruited progressively during the stance phase, with the slow motoneurons being active earlier than the fast (half-maximal spike frequency after 10-15% and 50-60% of the stance phase, respectively). The resting membrane potential was more hyperpolarized in fast motoneurons (64.6 +/- 6.5 mV) than in slow motoneurons (-52.9 +/- 5.4 mV). However, the threshold for the initiation of action potentials was not statistically significantly different in both types of flexor motoneurons. Therefore, action potentials were generated in fast motoneurons after a longer period of depolarization and thus later during the stance phase than in slow motoneurons. We show that motoneurons of the flexor tibiae receive substantial common excitatory inputs during the stance phase and that the difference in resting membrane potential between slow and fast motoneurons is likely to play a crucial role in their consecutive recruitment. (C) 2003 Wiley Periodicals, Inc.