Octopuses are boneless, brainy, and ancient invertebrates. They also have quite a problem on their hands, er, arms. Because they lack a rigid skeleton, the octopus can perform its tasks— reaching for a target, for example — in practically infinite ways. But, in order not to spend too much time in untying its eight arms, each arm must not move independently of one another.
“How the octopus controls each arm so that tasks can be performed without chaos, and without the need to spend enormous time in deciding how to perform a specific arm movement, is precisely what robotics designers would like to know,” says Tom McKenna, ONR Program Manager on this study.
What McKenna’s researchers* have discovered is quite remarkable. Apparently the brain of an octopus, unlike our own brain, operates much like a general in command of his troops. The general issues an order, and while the troops carry it out, the general goes on to other things, unaware of the details in how that order is carried out. Each arm appears to contain an independent peripheral nervous system and neural circuitry, which carries out the order independent of any further involvement on the part of the brain itself.
The octopus is considered to be among the most developed and intelligent animals in the invertebrate kingdom. Scientists have long been interested in how they learn, memorize, and even solve rather complicated behavioral problems. Some of these skills can be attributed to the high maneuverability of the arms and the capacity of the peripheral nervous system to perceive and process information.
“The objective of our study is to characterize control of the octopus arm, which has no joints and is highly flexible,” says McKenna. “This could very well be the basis of next-generation robotic arms for undersea, space, as well as terrestrial applications.”
*Binyamin Hochner at the Hebrew University of Jerusalem and Tamar Flash at the Weizmann Institute in Rehovot Israel.