How Do Octopuses Control 8 Arms? Scientists Discover Strange Segmented Nervous System

PUBLISHED
20 hours ago

They’ve termed the spatial map of its suckered arms the “suckeroptopy”.

RACHAEL FUNNELL
Writer & Senior Digital Producer

Edited
by
Maddy Chapman

Never challenge an octopus to a popping and locking dance off, that’s what my grandad always said. With eight worm-like arms, they exhibit extraordinary dexterity and control, and now scientists have uncovered a curious feature of their nervous systems that makes it possible. With segmented axial nerve cords that link up to individual suckers, octopuses exhibit a spatial mapping system for their arms never seen before, one scientists have named the “suckeroptopy”.

“If you're going to have a nervous system that's controlling such dynamic movement, that's a good way to set it up,” said Dr Clifton Ragsdale, Professor of Neurobiology at UChicago and senior author of the study, in a statement. “We think it’s a feature that specifically evolved in soft-bodied cephalopods with suckers to carry out these worm-like movements.”

Octopuses have eight arms and each arm has its own, extensive nervous system, which, combined, contain more neurons than are found in the animal’s brain. They are concentrated around the axial nerve cord (ANC), which encompasses all the suckers as it winds across the limb. Exactly how the ANC was connected to the musculature wasn’t clear, so a team studied the California two-spot octopus, Octopus bimaculoides, to find out.

By looking at thin strips of tissue samples taken from their arms, they observed how the neurons were packed into segments separated by gaps, known as septa. They also saw that each segment connected to a different muscle region from the next. It sounds weird, but it makes sense when you consider the arms all need to operate with local specificity while also moving synchronously as a whole appendage.