Interaction between descending input and thoracic reflexes for joint coordination in cockroach: I. Descending influence on thoracic sensory reflexes
Interaction between descending input and thoracic reflexes for joint coordination in cockroach: I. Descending influence on thoracic sensory reflexes
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蟑螂关节协调的下降输入与胸部反射之间的相互作用：I. 对胸部感觉反射的下降影响
DOI：
10.1007/s00359-007-0307-x
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发表时间：
2008
期刊：
影响因子：
--
通讯作者：
R. Ritzmann
中科院分区：
文献类型：
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作者：
Laiyong Mu;R. Ritzmann
被系住的蟑螂通过中胸（T2）腿的不对称运动从单侧触须接触转向（Mu and Ritzmann, journal of comcomphysil, 1991:1037 - 1054, 2005）。在转弯时，转弯内侧的腿（T2内侧腿）的运动模式与直走时明显不同。一种可能的神经机制是，从走路到腿内侧转动的转变可能是下行命令改变了一些关键的反射，这些反射会引发一系列腿部运动或姿势的物理变化，从而导致进一步的变化。这一假设有两个含义：第一，下行活动必须能够影响胸部反射。第二，一个人应该能够通过模仿反射级联中的一个更低的点，在没有下降信号的情况下启动旋转运动模式。在本文中，我们通过对声带器官反射的实验来解决第一个问题。伸展和放松股柔索器官可使降肌（Ds）和胫骨慢伸肌（SETi）的活动兴奋和抑制。然而，在消除下降活动后，Ds响应发生了变化，而SETi响应保持相似。在消除下降活性后，伸展尾侧脊索器官对Ds活性的抑制也发生了改变。
Tethered cockroaches turn from unilateral antennal contact using asymmetrical movements of mesothoracic (T2) legs (Mu and Ritzmann in J Comp Physiol A 191:1037–1054, 2005). During the turn, the leg on the inside of the turn (the inside T2 leg) has distinctly different motor patterns from those in straight walking. One possible neural mechanism for the transformation from walking to inside leg turning could be that the descending commands alter a few critical reflexes that start a cascade of physical changes in leg movement or posture, leading to further alterations. This hypothesis has two implications: first, the descending activities must be able to influence thoracic reflexes. Second, one should be able to initiate the turning motor pattern without descending signals by mimicking a point farther down in the reflex cascade. We addressed the first implication in this paper by experiments on chordotonal organ reflexes. The activity of depressor muscle (Ds) and slow extensor tibia muscle (SETi) was excited and inhibited by stretching and relaxing the femoral chordotonal organ. However, the Ds responses were altered after eliminating the descending activity, while the SETi responses remain similar. The inhibition to Ds activity by stretching the coxal chordotonal organ was also altered after eliminating the descending activity.