Satterlie R A, Nolen T G
Department of Biology, Arizona State University, Tempe, AZ 85287-1501, USA.
J Exp Biol. 2001 Apr;204(Pt 8):1413-9. doi: 10.1242/jeb.204.8.1413.
The classic view of swimming control in scyphozoan and cubozoan jellyfish involves a diffuse motor nerve net activated by multiple pacemaker sites that interact in a simple resetting hierarchy. Earlier modeling studies of jellyfish swimming, utilizing resetting linkages of multiple pacemakers, indicated that increases in pacemaker number were correlated with increases in the rate and regularity of network activity. We conducted a similar study using the cubozoan jellyfish Carybdea marsupialis, concentrating not only on the adaptive features of multiple pacemaker networks but also on the mechanism of pacemaker interaction. The best fit for our experimental data is a model in which pacemakers express a degree of independence. Thus, our results challenge the idea that pacemaker interactions in scyphozoan and cubozoan medusae are based on a strict resetting hierarchy. Furthermore, our data suggest that the combination of semi-independent linkage of pacemakers with the small pacemaker number characteristic of cubomedusae is important in (i) maintaining a biphasic modulatory capability in the swimming system, and (ii) allowing behaviorally appropriate directional responses to asymmetrical sensory inputs in the radially arranged jellyfish nervous system.
钵水母纲和立方水母纲水母游泳控制的经典观点涉及一个由多个起搏器位点激活的弥散性运动神经网，这些位点在一个简单的重置层级中相互作用。早期利用多个起搏器的重置联系对水母游泳进行的建模研究表明，起搏器数量的增加与网络活动的速率和规律性的增加相关。我们使用立方水母（Carybdea marsupialis）进行了一项类似的研究，不仅关注多个起搏器网络的适应性特征，还关注起搏器相互作用的机制。最符合我们实验数据的模型是起搏器表现出一定程度独立性的模型。因此，我们的结果挑战了钵水母纲和立方水母纲水母中起搏器相互作用基于严格重置层级的观点。此外，我们的数据表明，起搏器的半独立联系与立方水母特有的少量起搏器数量相结合，对于（i）在游泳系统中维持双相调节能力，以及（ii）在呈放射状排列的水母神经系统中允许对不对称感觉输入做出行为上适当的定向反应很重要。
