Dept. of Biology, University of Virginia, Charlottesville, VA 22904-4328, USA.
Prog Neurobiol. 2011 Feb;93(2):244-69. doi: 10.1016/j.pneurobio.2010.11.001. Epub 2010 Nov 18.
Swimming movements in the leech and lamprey are highly analogous, and lack homology. Thus, similarities in mechanisms must arise from convergent evolution rather than from common ancestry. Despite over 40 years of parallel investigations into this annelid and primitive vertebrate, a close comparison of the approaches and results of this research is lacking. The present review evaluates the neural mechanisms underlying swimming in these two animals and describes the many similarities that provide intriguing examples of convergent evolution. Specifically, we discuss swim initiation, maintenance and termination, isolated nervous system preparations, neural-circuitry, central oscillators, intersegmental coupling, phase lags, cycle periods and sensory feedback. Comparative studies between species highlight mechanisms that optimize behavior and allow us a broader understanding of nervous system function.
水蛭和七鳃鳗的游泳运动高度类似，但缺乏同源性。因此，机制上的相似性必然来自趋同进化，而不是共同的祖先。尽管人们对这两种环节动物和原始脊椎动物进行了 40 多年的平行研究，但缺乏对这项研究的方法和结果的密切比较。本综述评估了这两种动物游泳的神经机制，并描述了许多相似之处，这些相似之处为趋同进化提供了有趣的例子。具体来说，我们讨论了游泳的启动、维持和终止、分离的神经系统准备、神经回路、中枢振荡器、节间耦合、相位滞后、周期和感觉反馈。种间比较研究突出了优化行为的机制，使我们能够更广泛地理解神经系统的功能。
