Abstract
Motor output produced by central pattern generators is reliable, rhythmic, and robust to perturbations that an animal may experience over its lifetime. In the crustacean, Cancer borealis, the activity of the central pattern generators controlling the movement of the stomach and the heart have been studied with a wide range of techniques to understand how these neural circuits respond in to perturbation. In the present study, I explored the interactions of the cardiac and pyloric rhythms in baseline and temperature ramps using in vivo techniques. I also explored the effects of injected neuromodulator in animals. Evidence presented here suggests that while the pyloric and cardiac rhythms behave similarly during most baseline conditions and slight temperature increases, the rhythms decouple in response to more extreme perturbation. This suggests that the rhythms are not tightly controlled by descending modulation or input within the animal, nor by direct action between the heart and the pylorus. The rhythms are likely driven completely separately, or by loose modulatory control which causes them to behave similarly during baseline conditions but allows them to separate when exposed to extreme perturbations.