Coordination and Modulation of Motor Programs in Manduca Sexta

我们关于动物如何运动的大部分知识都是基于生物走路、飞行或游泳时使用的僵硬的关节骨骼和外骨骼。然而，没有脊椎的动物无脊椎动物是地球上数量最多的动物，几乎所有的动物都是软体动物，至少在它们生命的一部分时间里都有流体静力骨骼。这些爬行生物不是通过奔跑来逃避捕食者，而是使用伪装、化学防御和隐藏行为。因此，爬行已经进化成一种高度专业化的运动形式，使软体动物能够在复杂而狭窄的三维结构中移动，比如管子和树枝。柔软的身体，关节不会限制运动。这种动物可以无限自由地揉皱、压缩和旋转身体部位。从神经控制的角度来看，这种复杂的运动非常有趣，因为神经系统的运动协调与这些生物力学特征共同进化。拟议的研究使用一种毛毛虫，烟草角虫，Manduca sexta作为模型系统，以帮助理解流体静力运动的神经控制。我们将详细研究两个具体方面：首先，我们将确定爬行是如何由中枢神经系统控制的，以及它如何与周围结构（如肌肉和角质层）相互作用；其次，我们将研究毛毛虫爬行的一个独特方面，在腹部前腿的尖端使用弯曲的钩子攀登的能力。这种抓握是被动的，但非常强大，就像魔术贴挂钩，可以主动释放。我们将确定这种抓握是如何控制的以及它是如何融入正常爬行的。虽然这些研究的重点是了解动物的运动，但在新型柔性机器人的设计和控制方面具有潜在的应用前景。这种机器人可以用来在管道或复杂的结构中导航，比如血管和气管。最后，在研究前腿夹持机理时，有可能开发出被动附着但可以主动释放的新型粘合材料，以避免传统钩和环紧固中的撕裂力。

The majority of our knowledge about how animals move is based on creatures that walk, fly or swim using rigid articulated bones and exoskeletons. However, animals without backbones invertebrates are the most numerous animals on the planet and nearly all are soft-bodied with hydrostatic skeletons for at least part of their life. These crawling creatures do not escape predators by running but instead use camouflage, chemical defenses and cryptic behavior. As a consequence, crawling has evolved into a highly specialized form of locomotion that allows soft bodied animals to move in complex and confined three dimensional structures such as tubes and branches. With a soft body, joints do not restrict movements. Such animals can crumple, compress and rotate body parts with virtually unlimited freedom. Such complex movements are very interesting from a neural control perspective because movement coordination by the nervous system has co evolved with these biomechanical features. The proposed study uses a caterpillar, the tobacco hornworm, Manduca sexta, as a model system to help understand the neural control of hydrostatic movements. Two specific aspects will be examined in detail: first we will determine how crawling is controlled by the central nervous system and how it interacts with peripheral structures such as muscles and cuticle; secondly, we will examine a unique aspect of caterpillar crawling, the ability to climb using curved hooks at the tips of the abdominal prolegs. This gripping is passive but very strong like Velcro hooks and can be actively released. We will determine how this gripping is controlled and how it is integrated into normal crawling.Although focused on understanding animal locomotion, these studies have potential applications in the design and control of a new type of flexible robot. Such robots could be used to navigate through pipelines or intricate structures such as blood vessels and air tubes. Finally, in examining the mechanism of proleg gripping it is possible that new adhesive materials could be developed that attach passively but can be released actively to avoid the tearing forces in conventional hook and loop fastenings.