Segment specificity of load signal processing depends on walking direction in the stick insect leg muscle control system
Segment specificity of load signal processing depends on walking direction in the stick insect leg muscle control system
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DOI：
10.1523/jneurosci.5202-06.2007
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发表时间：
2007-03-21
影响因子：
5.3
通讯作者：
Bueschges, Ansgar
中科院分区：
文献类型：
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作者：
Akay, Turgay;Ludwar, Bjoern Ch.;Bueschges, Ansgar
陆地运动，来自负载传感器的感官反馈对于逐步改变正在进行的运动输出是重要的。研究了来自腿部的负荷信号对竹节虫步行系统中胸-髋关节运动神经元池的影响。在量角器髋部（ProCx）和牵伸器髋部（RetCx）运动神经元池的节律性交替活动中刺激负载传感器。感兴趣节段的交替活动是由动物机械刺激或离体胸神经节的药物激活引起的。来自腿部的负荷信号通过重置和携带四氢大麻酚关节中枢节律产生网络的活动来改变四氢大麻酚运动神经元活动的时间。在前腿和中腿，负荷信号诱导或促进RetCx活性，降低或终止ProCx活性。在后腿，反向转换被触发，随着负载的增加终止RetCx并启动ProCx活动。对半完整步行动物的研究表明，负荷对thc关节运动神经元的影响依赖于步行方向，负荷增加可促进功能站姿相运动神经元池（向前行走时，RetCx活动；向后行走时，ProCx活动）。因此，我们表明运动系统中感觉反馈的改变与行走方向有关。在最后一组消融实验中，我们表明负荷影响是由三组转子钟形感受器介导的。
terrestrial locomotion, sensory feedback from load sensors is important for altering ongoing motor output on a step-by-step basis. We investigated the influence of load signals from the leg on motoneuron pools of the thorax-coxa (ThC) joint in the stick insect walking system. Load sensors were stimulated during rhythmic, alternating activity in protractor coxae (ProCx) and retractor coxae (RetCx) motoneuron pools. Alternating activity in the segment of interest was induced by mechanical stimulation of the animal or pharmacological activation of the isolated thoracic ganglia. Load signals from the legs altered the timing of ThC motoneuron activity by resetting and entraining the activity of the central rhythm generating network of the ThC joint. In the front and middle legs, load signals induced or promoted RetCx activity and decreased or terminated ProCx activity. In the hindleg, reverse transitions were elicited, with increasing load terminating RetCx and initiating ProCx activity. Studies in semi-intact walking animals showed that the effect of load on the ThC-joint motoneurons depended on walking direction, with increased load promoting the functional stance phase motoneuron pool (in forward walking, RetCx activity; in backward walking, ProCx activity). Thus, we show that modifications of sensory feedback in a locomotor system are related to walking direction. In a final set of ablation experiments, we show that the load influence is mediated by the three groups of trochanteral campaniform sensilla.