Natures wonders: octopus scattered nerve system (Introduction)

by David Turell , Thursday, March 02, 2023, 23:54 (421 days ago) @ David Turell

The system is considered mathematically efficient:

https://www.scientificamerican.com/article/how-octopus-arms-bypass-the-brain/

OOctopuses' sucker-covered arms can act as if they contain partly independent mini brains. Each arm gathers sensory information to drive its own movements—and even those of other arms—without consulting major brain regions.

“'Their arms are so mobile; they're soft, and they can bend and twist and do all sorts of things,” says Melina Hale, a biologist at the University of Chicago. In a study in Current Biology, she and her colleagues reveal the strange connections that may facilitate these supple limbs' decentralized coordination.

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"The researchers traced the nerve cords with a powerful microscope and found that one type—the cords closest to the suckers—not only ran the length of an arm but also extended down another arm two arms away. All eight arms show this pattern. The layout was “totally different from anything that we'd ever seen before,” says Hale, who had expected the cords to create a structure similar to the central ring formed by larger peripheral nerves.

“'I think it's as simple as saying that it's mathematically efficient,” Kuuspalu says of the newly discovered pattern. If these connections carried sensory and motor signals, they would allow for rapid communication between relatively distant arms.

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“'It's not clear yet how the [intramuscular nerve cords] communicate or even if they do send signals across the body over long distances,” she adds. The study authors plan to delve into these questions next.
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“We can now approach our anatomical and behavioral studies a bit differently, with more focus on what any one arm is doing in concert with more distant arms in the ring,” says Roger Hanlon, a researcher at the Marine Biological Laboratory and frequent collaborator with Hale's group. “We are in that intriguing ‘mild state of confusion’ that is simultaneously perplexing and exhilarating when unexpected discoveries are revealed.'”

Comment: Please look at the illustration to appreciate the intricacy of the design. This did evolve by chance mutations.