I thought it might be a good idea to start a thread like this. Cephalopods, of course, are the only invertebrate example of an animal with a relatively complex brain which is organized very differently from ours and a brain-body mass similar to that of birds and mammals. There's been much written on cephalopod behavior and neurobiology per se, but I'm not sure how much we've drawn out of comparisons with vertebrate brains. One thing I can see from looking at schemata of various behavioral pathways in the cephalopod brain, and which I know Bernd Budelmann among others has discussed before, is that the cephalopod brain is not the hierarchically-organized brain that the vertebrate brain is, and each anatomical lobe is more bound to the others for a variety of functions. In addition, it strikes me as significant - I'm not sure how - that they have a complex brain but no spinal-cord-type structure (I don't think the commissure linking the arms or the various large nerves and giant axons going to each ganglion count either). At this point I'm sort of thinking aloud, but I'd like to start a discussion on this.