Octopus Arms Hold Over Two-Thirds of 500 Million Neurons, Distributing Intelligence

3 articles · Updated · WIRED · Aug 10

More than two-thirds of an octopus’s roughly 500 million neurons sit in its eight arms, showing that much of its intelligence is spread beyond its central, doughnut-shaped brain.
Each arm can move independently in any direction and can both taste and feel with high sensitivity, giving the animal a powerful local system for exploring and reacting.
A nerve ring links all eight arms, allowing seafloor exploration that is not always directed by the brain, a setup scientists say is unique among cephalopods.
The findings help explain complex behaviors such as unscrewing jars and throwing sand, while leaving open broader anatomical, behavioral and philosophical questions about how octopus control is organized.

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