Berri Stefano, Boyle Jordan H, Tassieri Manlio, Hope Ian A, Cohen Netta
HFSP J. 2009 Jun;3(3):186-93. doi: 10.2976/1.3082260. Epub 2009 Mar 26.
The ability of an animal to locomote through its environment depends crucially on the interplay between its active endogenous control and the physics of its interactions with the environment. The nematode worm Caenorhabditis elegans serves as an ideal model system for studying the respective roles of neural control and biomechanics, as well as the interaction between them. With only 302 neurons in a hard-wired neural circuit, the worm's apparent anatomical simplicity belies its behavioural complexity. Indeed, C. elegans exhibits a rich repertoire of complex behaviors, the majority of which are mediated by its adaptive undulatory locomotion. The conventional wisdom is that two kinematically distinct C. elegans locomotion behaviors-swimming in liquids and crawling on dense gel-like media-correspond to distinct locomotory gaits. Here we analyze the worm's motion through a series of different media and reveal a smooth transition from swimming to crawling, marked by a linear relationship between key locomotion metrics. These results point to a single locomotory gait, governed by the same underlying control mechanism. We further show that environmental forces play only a small role in determining the shape of the worm, placing conditions on the minimal pattern of internal forces driving locomotion.
动物在其所处环境中移动的能力关键取决于其主动的内源性控制与其与环境相互作用的物理学之间的相互作用。秀丽隐杆线虫是研究神经控制和生物力学各自作用以及它们之间相互作用的理想模型系统。在硬连线神经回路中只有302个神经元，线虫表面上解剖结构的简单掩盖了其行为的复杂性。事实上，秀丽隐杆线虫表现出丰富多样的复杂行为，其中大多数行为是由其适应性波动运动介导的。传统观点认为，秀丽隐杆线虫两种运动学上不同的运动行为——在液体中游泳和在致密凝胶状介质上爬行——对应于不同的运动步态。在这里，我们通过一系列不同的介质分析线虫的运动，并揭示了从游泳到爬行的平滑过渡，其特征是关键运动指标之间呈线性关系。这些结果表明存在一种单一的运动步态，由相同的潜在控制机制支配。我们进一步表明，环境力在决定线虫形状方面只起很小的作用，这为驱动运动的内力最小模式设定了条件。
