6. Feb, 2016

The ways of an octopus

Octopuses have always amazed the world with their intelligent behavior,  unique colorations to adapt to the background, and the way they  manage their flexible arms without getting them entangled.  The octopus is an example of advanced  cognitive adaptation, but how its brain (see yellow part in picture) works  still remains a mystery.  The octopus brain does not look at all like brains of other animals. Is has a huge  optic lobe underneath their eyes and a highly developed touch system which explains their excellent eye sight and sense of touch*. It has two memory systems that follow these two sensory systems.  A visual  and a  tactile memory used to identify signals in the environment for attack or retreat. But also to explore novel situations. But most amazing is how the octopus  controls its eight arms. Two-thirds of the nerve cells in the  nervous system are located  in the nerve cords of its arms (see yellow extensions in picture), which  makes the eight tentacles function as an extended brain. The central brain only has to trigger  a command to the arms,  which then carry out the full action sequence. Suggesting  that the entire movement  plan  is embedded in the arm itself and not in the central brain like in mammals. There is no propriocepsis, that is neural feedback paths of their movements  to the brain, so movements must be  monitored by 'seeing what happens'.  Octopuses are also known to use their arms in battles, by hurling sand and debris to its rivals**.   Getting  to know the octopus makes it hard to  accept  that this superb creature is still hunted down  to end up  in  sea food dishes  all over the world.

Further reading:



J. Z. Young's  "The Anatomy of the Nervous System of Octopus Vulgaris" (1971)