Setting the pace: new insights into central pattern generator interactions in box jellyfish swimming

Area of Science:

• Neuroscience
• Animal Behavior
• Evolutionary Biology

Background:

• Central Pattern Generators (CPGs) are neural circuits producing rhythmic behaviors across animals.
• Cnidarians, with radial symmetry and multiple pacemaker centers, offer unique models for CPG coordination.
• The box jellyfish, Tripedalia cystophora, possesses an advanced visual system influencing its swimming behavior.

Purpose of the Study:

• To investigate the interaction between the four pacemaker centers controlling swimming in the radially symmetric box jellyfish.
• To compare CPG coordination in cnidarians with existing models from bilaterian animals.

Main Methods:

• High-speed camera observations of Tripedalia cystophora swimming behavior under varying light conditions.
• Development of a numerical model of pacemaker interactions based on experimental data.
• Analysis of inter-pulse interval distributions and simulation of one, two, and four CPGs.

Main Results:

• A model incorporating full resetting and hyperpolarization best explained experimental data.
• Simulations indicated that two CPGs provided a better fit for swim pulse distribution than four.
• The proportion of long inter-pulse intervals was significantly influenced by the model, suggesting factors beyond visual input.

Conclusions:

• Visual input directly regulates swim CPGs in Tripedalia cystophora, but additional control mechanisms are likely involved.
• CPG function in radially symmetric cnidarians, like in bilaterians, depends on their integrated nervous and bodily environment.
• Further research is needed to elucidate the physiological linkages of cubozoan CPGs.