Soft-surface grasping: radular opening in Aplysia californica
Soft-surface grasping: radular opening in Aplysia californica
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DOI：
10.1242/jeb.191254
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发表时间：
2019-01
期刊：
影响因子：
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通讯作者：
C. Kehl;Joey Wu;Sisi Lu;D. Neustadter;R. Drushel;Rebekah K Smoldt;H. Chiel
中科院分区：
文献类型：
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作者：
C. Kehl;Joey Wu;Sisi Lu;D. Neustadter;R. Drushel;Rebekah K Smoldt;H. Chiel
摘要对于动物和机器人来说，抓取柔软、不规则的材料都是一项挑战。许多动物的饲养系统已经适应了这一挑战。特别是，海洋软体动物加利福尼亚海蛞蝓的摄食系统，一种多面手食草动物，允许它抓住和摄取不同形状，质地和韧性的海藻。在A. californica是一种被称为齿舌的结构，它是一种带有细齿的薄而柔韧的软骨片。以前的体外研究表明，内在肌，I7，负责打开齿舌。在体内损伤I7并不能阻止动物抓取和摄取食物。新的体外研究表明，即使I7肌肉不存在，齿舌腹侧表面上的一组细肌纤维-齿舌下纤维（SRF）-也会介导开放运动。在体外和体内病变表明，去除SRF导致深刻的缺陷，在齿舌开放，并显着降低进食效率。对SRF的作用的理论生物力学分析表明，它们诱导齿舌表面围绕齿舌表面中的中央折痕打开，并使齿舌表面拱起，使其能够柔和地符合不规则材料。基于完整动物的体内观察和磁共振成像的齿舌表面三维模型为生物力学分析提供了支持。这些结果表明，如何软抓紧器可以在喂养过程中工作，并建议人工软抓紧器的新设计。总结：新描述的肌肉纤维控制着一个柔软、灵活的表面，海洋蛞蝓用它来捕食海藻，这表明了一种构建柔软抓取装置的新机制。
ABSTRACT Grasping soft, irregular material is challenging both for animals and robots. The feeding systems of many animals have adapted to this challenge. In particular, the feeding system of the marine mollusk Aplysia californica, a generalist herbivore, allows it to grasp and ingest seaweeds of varying shape, texture and toughness. On the surface of the grasper of A. californica is a structure known as the radula, a thin flexible cartilaginous sheet with fine teeth. Previous in vitro studies suggested that intrinsic muscles, I7, are responsible for opening the radula. Lesioning I7 in vivo does not prevent animals from grasping and ingesting food. New in vitro studies demonstrate that a set of fine muscle fibers on the ventral surface of the radula – the sub-radular fibers (SRFs) – mediate opening movements even if the I7 muscles are absent. Both in vitro and in vivo lesions demonstrate that removing the SRFs leads to profound deficits in radular opening, and significantly reduces feeding efficiency. A theoretical biomechanical analysis of the actions of the SRFs suggests that they induce the radular surface to open around a central crease in the radular surface and to arch the radular surface, allowing it to softly conform to irregular material. A three-dimensional model of the radular surface, based on in vivo observations and magnetic resonance imaging of intact animals, provides support for the biomechanical analysis. These results suggest how a soft grasper can work during feeding, and suggest novel designs for artificial soft graspers. Summary: Newly described muscle fibers control a soft, flexible surface that the marine slug Aplysia californica uses to feed on seaweed, suggesting a novel mechanism for constructing a soft grasping device.