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)... 2016 This BCC Research report provides an ... RNA Sequencing (RNA Seq) market for the years 2015, ... and reagents, data analysis, and services. Use ... RNA-Sequencing market such as RNA-Sequencing tools and reagents, RNA-Sequencing ... affecting each segment and forecast their market growth, future ...
(Date:3/8/2016)... 2016   Valencell , the leading innovator ... has secured $11M in Series D financing. The ... venture fund being launched by UAE-based financial services ... investors TDF Ventures and WSJ Joshua Fund. Valencell ... triple-digit growth and accelerate its pioneering innovation in ...
(Date:3/3/2016)... England and DE SOTO, Kansas ... , U.S.-based Stroke Detection Plus® to offer Oncimmune,s ... risk assessment and early detection of lung cancer ... large employers, unions and individuals. --> Early ... unions and individuals. --> Oncimmune, a leader ...
Breaking Biology News(10 mins):
(Date:5/18/2016)... ... May 18, 2016 , ... Ryan Benton was diagnosed with Duchenne Muscular Dystrophy ... teens to early twenties. DMD is a relatively common progressive genetic disorder, which causes ... Benton’s condition was critical. He met with the founder of the Stem Cell ...
(Date:5/17/2016)... ... May 17, 2016 , ... ResearchDx, the ... consultancy based in Saudi Arabia, have formed a partnership to bring their expertise ... the Kingdom of Saudi Arabia (KSA). , The partnership addresses the specific ...
(Date:5/17/2016)... May 17, 2016 Strekin ... Basel, Switzerland announced today ... of P38 mitogen-activated protein kinase.      ... Strekin will build the necessary research foundation for ... which MAP Kinases play fundamental roles. Pamapimod has ...
(Date:5/17/2016)... MO (PRWEB) , ... May 17, 2016 , ... HOLLOWAY ... attend the ISPE Midwest Chapter’s Tech Ed Day on Thursday, May 19 in St. ... Busch Stadium. , HOLLOWAY AMERICA will participate in a vendor showcase during the early ...
Breaking Biology Technology: