Navigation Links
How the octopus forms an elbow

The octopus arm is extremely flexible. Thanks to this flexibility--the arm is said to possess a virtually infinite number of "degrees of freedom"--the octopus is able to generate a vast repertoire of movements that is unmatched by the human arm. Nonetheless, despite the huge evolutionary gap and morphological differences between the octopus and vertebrates, the octopus arm acts much like a three-jointed vertebrate limb when the octopus performs precise point-to-point movements. Researchers have now illuminated how octopus arms are able to form joint-like structures, and how the movements of these joints are controlled.

The new findings, which appear in the April 18th issue of Current Biology, are reported by Tamar Flash of the Weizmann Institute of Science, Binyamin Hochner and German Sumbre of Hebrew University, and Graziano Fiorito of the Stazione Zoologica di Napoli.

The extreme motility of the octopus arm demands a highly complex motor control system. Past work from Dr. Hochner's group showed that when retrieving food to its mouth, the octopus actually shapes its arm into a quasi-articulated structure by forming three bends that act like skeletal joints. This puts an artificial constraint of sorts on the arm's movement and simplifies the otherwise complex control of movement that would be needed for the arm to fetch food from a distant point to the octopus's mouth.

In the new work, the researchers sought to identify how the octopus manages to transform its extremely flexible arm into a structure that acts like a jointed appendage. By recording muscle activity as the arm creates the joint-like bends, the researchers found that the arm generates two waves of muscle contraction that propagate toward each other, setting the second, or medial, joint at their collision point. This is a remarkably simple mechanism for adjusting the length of the arm segments according to where the object is grasped along the arm. The arm also forms a proximal joi nt near where the arm meets the body, and a distal joint near the suckers that have grasped the food. The medial joint typically exhibits the most movement during food retrieval.

The authors also found evidence that, like certain types of human arm movements, octopus fetching movements are controlled in terms of joint angles, rather than by a system that relies on the brain's coordinate-based map of external space.

The presence of similar structural features and control strategies in articulated limbs (for example, jointed vertebrate arms) and flexible octopus arms suggests that these qualities have evolved convergently in octopuses and in vertebrates, and it also suggests that an articulated limb--controlled at the level of joints--is the optimal solution to the challenge of achieving precise point-to-point movements by a limb.


'"/>

Source:Cell Press


Related biology news :

1. Products containing specific probes for detecting alternative splice forms protected
2. IBM Transforms the Art of Scientific Expeditions
3. MIT researcher presents new view of how the cortex forms
4. Carnegie Mellon U. transforms DNA microarrays with standard Internet communications tool
5. New study explores beetle species with two forms of females
6. AIDS-related cognitive impairment exists in two separate forms
7. Creating new life forms that may help eradicate cancer affecting women
8. Scientists discover new life forms in the Arctic Ocean
9. Genetic pathways to curable and incurable forms of pancreatic cancer identified
Post Your Comments:
*Name:
*Comment:
*Email:


(Date:3/9/2016)... March 9, 2016  Crossmatch ® , a ... solutions, today announced the addition of smart features ... multi-factor authentication platform. New contextual and application-specific ... step-up security where it,s needed most — while ... DC . --> Washington, ...
(Date:3/3/2016)... 2016  2016FLEX, organized by FlexTech, a SEMI ... in flexible, hybrid and printed electronics. More than ... have gathered for short courses, technical session, exhibits, ... The Flex Conference celebrates its 15 th ... organizations, and universities contributing to the adoption of ...
(Date:3/2/2016)... DUBLIN , March 2, 2016 /PRNewswire/ ... the addition of the "Global Biometrics ... to their offering. --> ... the "Global Biometrics as a Service ... --> Research and Markets ...
Breaking Biology News(10 mins):
(Date:5/3/2016)... ... May 03, 2016 , ... Leading ... 2016 on May 31st and June 1st at The Four Seasons Hotel Boston. ... in the life sciences, offering exclusive access to key decision makers who influence ...
(Date:5/3/2016)... , May 3, 2016 ... Assessing Developers and Producers of Those Competitor Biologics  ... to Companies, Activities and Prospects ,  Who ... companies? And what are their sales potentials? Discover, ... you see results, trends, opportunities and revenue forecasting. ...
(Date:5/2/2016)... YORK , May 2, 2016 ... announces that its technology partner Mannin Research Inc. will ... Ophthalmology (ARVO), which takes place from May 1-5, 2016 ... executives will be meeting with its vendors and research ... explore business development goals and other collaborative opportunities for ...
(Date:4/29/2016)... (PRWEB) , ... April 30, 2016 , ... The MIT ... textile design, the bioLogic team explored how bacterial properties can be applied to fabric ... using Natto bacteria, which move in response to humidity change. The team harvested Natto ...
Breaking Biology Technology: