NOV 07, 2020 7:14 AM PST

How the Suction Cups on Octopus Arms Detect Their Surroundings

WRITTEN BY: Carmen Leitch

Scientists have taken a close look at the physiology of the octopus, creatures that are ancient and unique. Their arms can operate independently of their central brain, each arm has a large bunch of neurons at its base, so in a sense, these animals have nine brains. Researchers have now learned more about how octopuses move their arms and make choices without using their central brain. The findings identified a group of sensors in the suction cups on octopus arms that can transmit information about what it's touching; they have been reported in Cell.

Image credit: Pxhere

The sensors in the octopus arms are known as chemotactile receptors and help the animal determine if it's contacting prey. These receptors detect molecules that don't dissolve easily in water.

"We think because the molecules do not solubilize well, they could, for instance, be found on the surface of octopuses' prey and [whatever the animals touch]. So, when the octopus touches a rock versus a crab, now its arm knows, 'OK, I'm touching a crab [because] I know there's not only touch but there's also this sort of taste,'" explained the senior study author Nicholas Bellono, an assistant professor of molecular and cellular biology. "

The signals that are transmitted from these receptors to cells and the nervous system also depend on what is being touched.

"We think that this is important because it could facilitate complexity in what the octopus senses and also how it can process a range of signals using its semi-autonomous arm nervous system to produce complex behaviors," Bellono said.

About two-thirds of the neurons in an octopus are found in its arms, which are complex structures. These arms can grab items and identify them even when one is severed from the animal's central brain. The researchers wanted to learn more about how the receptors help the arms find out about what they touch and make decisions.

The scientists identified which suction cups on the arms are detecting molecules, and studied them by cloning the genes that encode for them and then expressing them in cell lines and frog eggs. When the receptors in this model were exposed to various molecules, they tended to react only to molecules that did not dissolve in the water, and did not react to soluble molecules like sugars and salts.

When they took these findings to octopuses in the lab, they found that indeed, the octopus receptors were responsive to a non-dissolving class of molecules called terpenoids, which are naturally occurring.

"[The octopus] was highly responsive to only the part of the floor that had the molecule infused," Bellono said. This led the researchers to believe that the receptors they identified pick up on these types of molecules and help the octopus distinguish what it's touching. "With the semi-autonomous nervous system, it can quickly make this decision: 'Do I contract and grab this crab or keep searching?'"

"We're now trying to look at other natural molecules that these animals might detect," Bellono said.

Sources: Science Daily via Harvard University, Cell

About the Author
  • Experienced research scientist and technical expert with authorships on over 30 peer-reviewed publications, traveler to over 70 countries, published photographer and internationally-exhibited painter, volunteer trained in disaster-response, CPR and DV counseling.
You May Also Like
AUG 31, 2020
Genetics & Genomics
A Treatment Avenue Opens for a Rare Disorder
AUG 31, 2020
A Treatment Avenue Opens for a Rare Disorder
Krabbe disease or globoid cell leukodystrophy is a rare and deadly disorder that affects about one in every 100,000 infa ...
SEP 09, 2020
Cell & Molecular Biology
Why Liver Gene Therapies Have Not Worked & How to Improve Them
SEP 09, 2020
Why Liver Gene Therapies Have Not Worked & How to Improve Them
Diseases that are caused by errors in a gene might be cured if we could correct those errors, or genetic mutations.
SEP 13, 2020
Cell & Molecular Biology
RNA Found on the Surface of Human Cells
SEP 13, 2020
RNA Found on the Surface of Human Cells
The surface of a cell carries many features to help it carry out its functions, communicate with other cells, gather inf ...
OCT 25, 2020
Cell & Molecular Biology
Revealing More About the Genetics of Ewing Sarcoma
OCT 25, 2020
Revealing More About the Genetics of Ewing Sarcoma
Ewing sarcoma is a rare kind of cancer that tends to impact young people and occurs in bones or the tissue around them. ...
NOV 02, 2020
Genetics & Genomics
Denisovan DNA Recovered From the Tibetan Plateau
NOV 02, 2020
Denisovan DNA Recovered From the Tibetan Plateau
Denisovans were ancient hominins that were discovered only recently, and they had a wider range than previously known.
NOV 23, 2020
Microbiology
Drug Resistance in Tuberculosis Involves a Unique Mechanism
NOV 23, 2020
Drug Resistance in Tuberculosis Involves a Unique Mechanism
The pathogenic bacterium that causes tuberculosis, Mycobacterium tuberculosis, does not multiply quickly, so researchers ...
Loading Comments...