nini said:
this is so wierd , but i was reading that octos have brainy arms,that have a mind of there own, and free will!!!
sorry, as much as most of u already know about octos, this probably does not surprise any 1,first time i heard about it, sounds cool, is this true?
Yes, cephalopods generally have their intelligence a lot more "spread out" than other smart animals. There have been some (mean) studies of how much an octo arm can do on its own, if separated from the animal, and they have some grasping and lifting behaviors, and the suckers each have their own ganglion, like a little brain, that makes simple decisions about what is good to grab onto or push away.
There were some studies that show that any learning happens in the brain in the head, though, so you can't teach a severed arm anything new. However, some of the behavior is decided out at the arm, and so the learning center doesn't have access to it. In particular, the octo can learn to react differently to rough and smooth things, because the arm sends that info back to the brain, but it can't learn to distinguish light and heavy, because the arm decides how much force to use to lift the object without telling the brain what it decided, so the "learning center" doesn't get a report from the arm as to how heavy the thing it picked up was. (That's the theory, anyway-- there may be other interpretations).
One of the things that fascinates me most about cephalopods is that they are really the only (unless you count the smartest insects as intelligent) intelligent animals that evolved completely independently from vertebrates like us, so if we want to learn about the possible different ways nervous systems might be, studying cephs is a great idea, since they had a completely independent path to solving the same "design" problems. It's frequently pointed out that octo eyes make more sense than human ones-- ours are "inside-out" in that light has to pass through some nerve cells before it gets to the sensors on the retina, while octos have the retinas on the outside where the light goes directly.
I posted a long rambling bit about this last year, tho I didn't mention the arms specifically:
http://www.tonmo.com/community/index.php?threads/2979/#post-46932
I found the octo section of my "comparative nervous systems" class one of the more fascinating topics (although the whole class was good-- the prof, John Allman published a book on the topic, too, although I don't remember how much it has on ceph brains.)
