Identification of the origin of force-feedback signals influencing motor neurons of the thoraco-coxal joint in an insect
Identification of the origin of force-feedback signals influencing motor neurons of the thoraco-coxal joint in an insect
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DOI：
10.1007/s00359-019-01334-4
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发表时间：
2019-04-01
影响因子：
2.1
通讯作者：
Bueschges, Ansgar
中科院分区：
文献类型：
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作者：
Haberkorn, Anna;Gruhn, Matthias;Bueschges, Ansgar
昆虫四肢上Campaniform sensilla （CS）的力反馈有助于使运动输出适应环境条件，但我们才刚刚开始揭示介导这些影响的神经控制机制。我们研究了CS组通过对残肢施加水平和垂直力来影响竹节虫胸-臀关节的控制。通过记录细胞外量角器（ProCx）和牵开器（RetCx）神经来评估CS组消融的运动效应。细胞外记录显示，刺激感受器的效果与其广泛的定向敏感性范围一致：例如，通过消融几组转子CS可以减少后弯曲反应的RetCx放电，而消融胫骨和股骨感受器几乎没有影响。相比之下，ProCx运动神经元在前向刺激下的活动主要受到单个CS组消融的影响（G2）。用荧光染料对粗隆、股骨和胫骨CS组进行染色填充，显示出共同的投影模式，组特异性较低。这些发现支持了CS反馈的影响是由运动前中间神经元的活动决定的，促进快速和任务依赖的适应不断变化的环境条件。
Force feedback from Campaniform sensilla (CS) on insect limbs helps to adapt motor outputs to environmental conditions, but we are only beginning to reveal the neural control mechanisms that mediate these influences. We studied CS groups that affect control of the thoraco-coxal joint in the stick insect Carausius morosus by applying horizontal and vertical forces to the leg stump. Motor effects of ablation of CS groups were evaluated by recording extracellularly from protractor (ProCx) and retractor (RetCx) nerves. Extracellular recordings showed that the effects of stimulating the sensilla were consistent with their broad ranges of directional sensitivity: for example, RetCx firing in response to posterior bending could be reduced by ablating several groups of trochanteral CS, whereas ablation of tibial and femoral sensilla had little effect. In contrast, ProCx motor neuron activity upon anteriorly directed stimuli was affected mainly by ablating a single CS group (G2). Dye fills of trochanteral, femoral and tibial CS groups with fluorescent dyes revealed a common projection pattern with little group specificity. These findings support the idea that the influences of CS feedback are determined by the activities of pre-motor interneurons, facilitating fast and task-dependent adaptation to changing environmental conditions.