At first I was rather uncomfortable with the idea of a central pattern generator in the nervous system, functioning to automatically determine our behavior. Seeing the central generator as somewhat of an intermediary between a higher command center that generates an excitatory impulse (input) and the patterned motor output makes the central generator fit better into the nervous system. Given the importance of interneurons in the nervous system, of intermediary connections and communication between various regions of the NS, the idea of a central pattern generator acting as such an intermediary follows this common theme that is so important to the nervous system as a whole. The central pattern generator is tied with our genetic selves, our unlearned and "preprogrammed" operations that are most likely to be a early adaptation in our evolutionary history. The fact that the behavior of many "lower" animals is attributed to these innate behavior patterns is convincing that the central pattern generator is more related to survival behavior and basic functioning than to "higher" behavior--behavior that reflects a higher cognitive development.
What I am most uncomfortable with is the way in which we go about determining the methodology and organization of the nervous system. I cannot completely accept the procedures used by scientists that result in the death or disfigurement of the subject animals. I was particularly uncomfortable when you were describing the experiment involving the separation of the nervous system from the body of the crawfish. It does not seem right that we use life in this way. Unfortunately, I do not know of any other way to learn about the nervous system besides hands-on experimentation and observation.
Glad CPG fits, helps to link neurons and behavior. Careful, though, about equating CPG's with genetics; they can be expressions of both genetic and learned information (usually both). And have a pretty great degree of flexibility.
I share your concern about animal usage, even if (perhaps) it didn't sound like it in class. I don't like to see animals in perturbed states. But no, I don't know of any other way to become more knowledgeable and wiser, hopefully for the benefit not only of humans but of living organisms generally. Happy to talk more about this, if you like. PG