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Octopus Parcels Out Brain Power in Remarkable Way
By Will Dunham
WASHINGTON (Reuters) - The octopus, already considered among the smartest of all invertebrate animals, boasts complex nervous systems in each of its eight arms that act autonomously from the creature's brain and control the movements of the extremities, Israeli researchers have found.
Writing in Friday's issue of the journal Science, the scientists said the well-developed brain of the octopus decides whether an arm should move -- to grasp food, for example -- but leaves it up to these eight nervous systems to carry out the order as they see fit.
This is the first time that such a remarkable quality has been found anywhere in the animal kingdom, said lead researcher Binyamin Hochner of the Hebrew University of Jerusalem.
He added that it is likely that the closest cousins of the octopus -- including squids and cuttlefish -- also possess this unique distribution of brain power. Octopuses, squids and cuttlefish all belong to a class of mollusks called cephalopods.
Octopuses, found commonly in the world's oceans and ranging in size from less than an inch (2.5 cm) up to 30 feet (9 meters), are among the most ancient animals on Earth and have the most complex brain of any animal without a backbone. The ancestors of modern cephalopods diverged from a more primitive externally shelled variety perhaps 438 million years ago.
Hochner and his colleagues have been studying octopuses for the past six years in an effort to gain insight into how to make robotic arms that are capable of the virtually infinite degrees of movement available to the octopus arm. Better, more flexible robot arms could be quite useful in surgical procedures and industrial applications, they said.
AN OCTOPUS CEO
But this wide range of movement requires an especially complex control by the octopus nervous system. The researchers found that the octopus brain serves somewhat like the CEO of a corporation -- making the large decisions and delegating the details to subordinates, in this case these unique peripheral nervous systems embedded in the eight arms.
Even after severing the connection between the brain and arm's nervous system in the laboratory, the researchers observed natural reaching movements in octopuses when the skin on their arms was tickled or stimulated electrically.
This suggests that the basic motor program for controlling voluntary movement in the highly flexible arm is embedded within the neural circuitry of the arm itself, they said.
``You have a hierarchy in the controlling system, where the brain is commanding the peripheral (nervous systems),'' Hochner said in a telephone interview.
``The central brain is very developed in the octopus. It deals with visual information and memory and such. ... The minute the brain wants to recruit the arm into a certain task -- like sending the arm to a specific target -- then it sends a command to the nervous system of the arm, which then issues the movement.''
The octopus brain determines only the direction of the extension of the arm and the speed at which the extension will be executed, the researchers found. All the detailed commands involving activation of the arm muscles are issued by the nervous system of the arm itself, they added.
``The arm is an autonomous part of the system,'' Hochner added.
But the central control of the brain means that the arms are not acting in counter purpose -- one arm not knowing what the other arm is doing.
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<BLOCKQUOTE><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><HR>
Octopus Parcels Out Brain Power in Remarkable Way
By Will Dunham
WASHINGTON (Reuters) - The octopus, already considered among the smartest of all invertebrate animals, boasts complex nervous systems in each of its eight arms that act autonomously from the creature's brain and control the movements of the extremities, Israeli researchers have found.
Writing in Friday's issue of the journal Science, the scientists said the well-developed brain of the octopus decides whether an arm should move -- to grasp food, for example -- but leaves it up to these eight nervous systems to carry out the order as they see fit.
This is the first time that such a remarkable quality has been found anywhere in the animal kingdom, said lead researcher Binyamin Hochner of the Hebrew University of Jerusalem.
He added that it is likely that the closest cousins of the octopus -- including squids and cuttlefish -- also possess this unique distribution of brain power. Octopuses, squids and cuttlefish all belong to a class of mollusks called cephalopods.
Octopuses, found commonly in the world's oceans and ranging in size from less than an inch (2.5 cm) up to 30 feet (9 meters), are among the most ancient animals on Earth and have the most complex brain of any animal without a backbone. The ancestors of modern cephalopods diverged from a more primitive externally shelled variety perhaps 438 million years ago.
Hochner and his colleagues have been studying octopuses for the past six years in an effort to gain insight into how to make robotic arms that are capable of the virtually infinite degrees of movement available to the octopus arm. Better, more flexible robot arms could be quite useful in surgical procedures and industrial applications, they said.
AN OCTOPUS CEO
But this wide range of movement requires an especially complex control by the octopus nervous system. The researchers found that the octopus brain serves somewhat like the CEO of a corporation -- making the large decisions and delegating the details to subordinates, in this case these unique peripheral nervous systems embedded in the eight arms.
Even after severing the connection between the brain and arm's nervous system in the laboratory, the researchers observed natural reaching movements in octopuses when the skin on their arms was tickled or stimulated electrically.
This suggests that the basic motor program for controlling voluntary movement in the highly flexible arm is embedded within the neural circuitry of the arm itself, they said.
``You have a hierarchy in the controlling system, where the brain is commanding the peripheral (nervous systems),'' Hochner said in a telephone interview.
``The central brain is very developed in the octopus. It deals with visual information and memory and such. ... The minute the brain wants to recruit the arm into a certain task -- like sending the arm to a specific target -- then it sends a command to the nervous system of the arm, which then issues the movement.''
The octopus brain determines only the direction of the extension of the arm and the speed at which the extension will be executed, the researchers found. All the detailed commands involving activation of the arm muscles are issued by the nervous system of the arm itself, they added.
``The arm is an autonomous part of the system,'' Hochner added.
But the central control of the brain means that the arms are not acting in counter purpose -- one arm not knowing what the other arm is doing.
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