Curr. Biol. doi: 10.1016/j.cub.2009.07.067 (2009)

Octopuses have the peculiar challenge of controlling eight appendages that can assume an almost limitless number of positions. They seem to accomplish this by consolidating the control of complex, coordinated movements into specific areas of their nervous system — rather than having a one-to-one relationship between a body part and a specific brain area.

Letizia Zullo, now at the Italian Institute of Technology in Genova, and her colleagues placed electrodes in 35 parts of the animal's nervous system. Low-voltage stimulation of different areas evoked simple responses, such as a change in skin colour or small eyelid movements. Higher voltages elicited more complex responses, such as inking and jet-propelled swimming.