[Coral-List] Yes, the Octopus Is Smart as Heck. But, Why?

Douglas Fenner douglasfennertassi at gmail.com
Thu Dec 13 20:23:24 UTC 2018

I read that the octopus brain has about 10% of all it's nervous system's
nerve cells.  So maybe Octopus is an animal with nerves all through its
body and arms, with a small concentration in a ganglion between its eyes
that we call a brain.  Invertebrate nervous systems are a bit different
from vertebrate nervous systems.  By the way, I forgot to mention that in
vertebrates, circuits of nerve cells in the spinal cord can produced
stepping.  When the connection between spinal cord and brain is severed,
the spinal cord can produce coordinated patterns of reflexive stepping.
Not the same as normal walking, but it is there.  Rather like movements an
octopus arm can make on its own, or swimming movements a lobster tail can
make on it's own (run by a ganglion near the swimmerettes).  So there are
similarities as well.
     Octopus eye is a camera eye that is similar to ours, though it evolved
completely independently of ours.  The retina, though, is very different,
with the light-absorbing pigments in microvilli instead of in modified
cilia as in our retinas.  The microvilli are arranged horizontally in sets
at right angles if I remember, instead of vertically like the modified
cilia we call rods and cones in our retinas.  Each eye has a big optic lobe
behind it full of neurons to process the signals, each optic lobe a bit
bigger than the brain between them.  Giant clam eyes have a mirror behind
them like a reflecting telescope, and two layers of retinal photoreceptor
cells.  Here's looking at you, kid!
     Cheers, Doug

On Thu, Dec 13, 2018 at 4:56 AM Eugene Shinn via Coral-List <
coral-list at coral.aoml.noaa.gov> wrote:

> Very thought provoking stuff. Possibly the octopus is a brain that
> happens to have eyes and arms. Gene
> --
> No Rocks, No Water, No Ecosystem (EAS)
> ------------------------------------ -----------------------------------
> E. A. Shinn, Courtesy Professor
> University of South Florida
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Douglas Fenner
Ocean Associates, Inc. Contractor
NOAA Fisheries Service
Pacific Islands Regional Office
PO Box 7390
Pago Pago, American Samoa 96799  USA

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