Friday Cephalopod: Looking haughty »« If only he’d had a decent budget and campaign staff

Learn your neuroanatomy lingo

Go study this and master the vocabulary. Everyone is so familiar with our brains with their parietal lobes and sulci and ganglia, but do people ever stop to contemplate the cephalopod brain? Nooooo. And it’s pretty cool.

Possibly the most obvious difference is that the nervous system of most invertebrates develops ventrally, rather than dorsally, like ours. Imagine that your nervous system formed on the other side of your throat, so that as the brain expanded, it had to wrap itself around your esophagus.

Comments

  1. jnorris says

    I see the cephalopod brain has an ant tunnel. Given there are no ants under the sea, this must have evolved while the cephalopods were land dwellers. Is this one of those evolutionary vestigial organs?

  2. bbgunn says

    Imagine that your nervous system formed on the other side of your throat, so that as the brain expanded, it had to wrap itself around your esophagus.

    For me, that would come in handy at some of those ‘all you can eat’ buffets.

  3. Snoof says

    So their retina is the right way around… and their _brain_ is not?

    Are there _any_ animals with a nervous system that would pass a quality inspection?

  4. says

    I get used to a lot of cephalopod weirdness and now I discover this. I don’t think you’ll be running out of strange things about them to tell us.

  5. Sastra says

    Imagine that your nervous system formed on the other side of your throat, so that as the brain expanded, it had to wrap itself around your esophagus.

    “Don’t think before you speak.”

    I imagine there would be a lot of openings in the conservative movement for a person like that.

  6. john says

    Nile catfish has a ventral spine. Can’t think of any other vertebrates, though flounders try to compromise, and so do humans in a different way. And please don’t respond that the Nile catfish is upside-down. That makes about as much sense as claiming that all humans are muslims, except for the apostates. That catfish is arguably the only vertebrate that is not upside-down.

  7. TonyJ says

    As my 7-year-old son likes to say (he went to octopus camp at the Seattle Aquarium this summer): An octopus better be careful drinking a slurpee or it’ll get a really bad case of brain freeze!

  8. says

    Nile catfish has a ventral spine.

    Uh, what? No! Like ALL vertebrates, the Nile catfish has a dorsal nerve cord, with a notochord (which is replaced by vertebrae) ventral to it. It has the standard anatomy. It would be extremely surprising to find a vertebrate that had completely inverted the fundamental developmental pathways in axis formation.

    I think you’re confused by the fact that the Nile catfish lacks a dorsal fin and dorsal spines — the spiky pointy bony needles that brace a membranous fin and are sometimes modified into defensive structures. Not spines as in backbones, but spines as in fin rays.

  9. says

    …so that as the brain expanded, it had to wrap itself around your esophagus.

    That’s just silly. Next you’ll be telling us that the nerve linking a giraffe’s brain to its larynx takes a 15 ft detour down its neck, so that it can loop around the aorta.

  10. Ogvorbis: broken and cynical says

    I know some people who’s colon is wrapped around their brain. Does that count?

  11. Nick Gotts (formerly KG) says

    Imagine that your nervous system formed on the other side of your throat, so that as the brain expanded, it had to wrap itself around your esophagus.

    Well we’ve seen in the last few days that in the case of right-wing pundits, the brain is contained in a small pouch in the side-wall of the colon.

  12. says

    I learn something new every time I visit your blog, PZ. I missed this in comparative anatomy, way, way, back, but then cephalopods are notoriously rare in WV.

    But then, I can’t resist it, cephalopods are almost thinking with their stomachs.

  13. Paulino says

    PZ, the molluscan “brain” doesn’t wrap around the esophagus due to growth. Actually the pedal ganglia pair, that is ventral to the esophagus, and cerebral ganglia pair, that is dorsal, along with their correspondent commissures form a ring around it. In more active mollusks, that need more info-processing power, the ganglia tend to concentrate and fuse, forming a “brain”, more commonly called a nerve ring.

  14. billydee says

    I always get the post. buccal l. mixed up with the superior buccal l.
    (What’s an l.?)

  15. nathanaelnerode says

    What I’m getting out of this is that cephalopods think *very differently* from us vertebrates. Have we done some MRIs to work out what parts light up during different types of thinking processes?