Why the octopus brain is so extraordinary - Cláudio L. Guerra

Because their decentralized nervous system and autonomously controlled appendages embody alternative control principles, studying octopus neural organization can inspire soft robots with flexible, distributed control and broaden theories of how intelligence can emerge.

Because an unusually large brain-to-body ratio and high neuron count give octopuses neural resources comparable to some mammals, they can support complex cognition such as puzzle solving, observational learning, and tool use.

Because they have no bones or fixed joints, cephalopod limbs can bend at any point and in any direction, which removes skeletal constraints and creates a vastly larger space of possible limb configurations than vertebrates have.

Because the cephalopod nervous system stores whole behavioral programs that are triggered and propagated through a distributed network, actions are generated by invoking complete behaviors rather than by the brain specifying exact joint-by-joint commands—replacing a detailed body-map with a behavior library.

Because arms contain large numbers of local neurons and can execute behavioral commands independently of the central brain, each arm can make parallel, adaptive decisions in novel situations, producing high flexibility and creative behaviors like opening containers or changing skin patterns.

Because contact triggers a muscle-activation wave from the tip to the base while another wave travels from the base to the tip and they meet at a point, an octopus arm can autonomously determine exactly where to bend during a reach.

Because roughly 500 million neurons are distributed across interconnected ganglia (central brain ~10%, optic lobes ~30%, tentacles ~60%), octopus processing is decentralized so different structures perform specialized local computations instead of relying on a single central controller.