//
you're reading...

Neurobiology

No nerves lost: Octopuses can regenerate their nervous system.

Reference: Imperadore, Pamela, et al. “From injury to full repair: nerve regeneration and functional recovery in the common octopus, Octopus vulgaris.” Journal of Experimental Biology 222.19 (2019): jeb209965.

The nervous system of an octopus is nothing short of amazing. Each of the octopus’ eight tentacles is controlled by a cluster of nerve cells, called ganglia, and the ganglia are in turn controlled by the centralized brain. As it turns out, the octopus can also regenerate parts of its nervous system after an injury.

Cutting this nerve turns the skin on its side of the mantle white. Image source: Imperadore et al., 2017 (1).

A team of scientists, headed by Graziano Florito of Stazione Zoologica Anton Dohrn in Naples, Italy, investigated whether the common octopus, or Octopus vulgaris, can regenerate its pallial nerves. These nerves run from the centralized brain in the head to ganglia in the octopus mantle on both sides of the body. The scientists found that if an octopus pallial nerve was cut, it repaired itself within five months.

The two pallial nerves have two very important functions for the octopus. First, they regulate breathing by controlling a respiratory muscle in the mantle. Second, they help change the color of the mantle, which is how octopuses communicate with each other. To live a good life, octopuses need to both breathe and talk to others, so the regenerative potential of the pallial nerve was an exciting finding for the scientists – and good news for Octopus vulgaris.

Octopuses on their last nerve

To study regeneration of the pallial nerves, the researchers caught fourteen wild octopuses in the Bay of Naples. When the research team anesthetized the animals and cut one of their two pallial nerves with fine scissors, leaving the other one intact, they saw that the respiratory muscle on the corresponding side of the mantle stopped contracting. They also saw that on that side, the color of the mantle skin went from brown to white.

To see if the octopuses were doing well after the surgery, the researchers tempted them with a tasty snack. After the animals came out of anesthesia, the researchers put live crabs in their tanks. The octopuses promptly attacked the crabs, showing their normal predatory behavior and not showing any distress about the surgery.

Over the next several weeks, recovery of the pallial nerve could be observed with the naked eye, as its two behavioral functions slowly returned to the octopuses. First, the white skin of the mantle developed some brown spots that formed color patterns when the animals were at rest. After a month and a half, the mantle skin returned to normal, forming color patterns when the octopuses were hunting prey or moving around the tank.

Breathing returned as well. Four weeks after the pallial nerve was lesioned, the mantle opening resumed its normal expanding and contracting, which showed that the paralyzed respiratory muscle started working again. For the first time, regeneration of the octopus pallial nerve was confirmed by the recovery of the normal behavior that depends on this nerve.

Making repairs 

The return of breathing and skin patterning suggested that the transected pallial nerve had managed the repair itself, but the only way to make sure of this discovery was to see directly what the nerve looked like in the octopus tissue. The scientists found that the two stumps of the lesioned nerve, one on the mantle side and one on the head side, had reconnected by 45 days after the injury. The fibers of the nerve had crossed the site of the lesion and formed a network with the local nerve cells in the mantle.

Octopuses communicate with each other by forming color patterns on their skin. This ability is lost when the pallial nerve is cut, but returns as the nerve stumps reconnect. Image source: Taken from Pixabay

To test if those regenerated fibers were indeed functional nerve fibers, the researchers exposed the regenerated nerve and placed an electrode on each side of the lesion. The electrode on the head side stimulated the nerve and the electrode on the mantle side recorded the activity of the regenerated nerve fibers. If electrically stimulated, the pallial nerve itself produced electric current and carried it to the other side of the lesion – confirming for the first time that the reconnected nerve stumps form a perfectly functional nerve.

Regeneration on the tree of life

It has been known for a long time that octopuses are master regenerators – the first study describing regeneration of the pallial nerve was published in 1932 (2). Besides their nervous system, octopuses can also regenerate their tentacles (3) and parts of the eye (4).

This exceptional regenerative ability is not unique to octopuses – other members of Cephalopod species, like cuttlefish, can also regenerate arms (1). But even among vertebrates, some animals can rival their reputation of incredible regenerators. 

Many fish and amphibian species rely on regeneration to recover from injuries to their organs and body parts. Zebrafish can replace missing heart tissue, and the Mexican axolotl salamander can regenerate an entire limb (5, 6). 

By contrast, mammals are notoriously bad at regeneration, land and ocean species alike. Mice and young human children can sometimes regenerate severed fingertips (6), and the regenerative abilities of ocean mammals, like whales and dolphins, are still very poorly understood, possibly because it is difficult to work with these animals in a biology research lab.

While octopuses do not reign as supreme regenerators in the animal kingdom, they certainly have an upper tentacle here when compared to humans.

 

Additional references: 

  1. Imperadore, P., Shah, S. B., Makarenkova, H. P., & Fiorito, G. (2017). Nerve degeneration and regeneration in the cephalopod mollusc Octopus vulgaris: the case of the pallial nerve. Scientific reports, 7, 46564
  2. Sereni, E., & Young, J. Z. (1932). Nervous degeneration and regeneration in cephalopods. Pubbl. Staz. Zool. Napoli, 12, 173-208.
  3. Lange, M. M. (1920). On the regeneration and finer structure of the arms of the cephalopods. Journal of Experimental Zoology, 31(1), 1-57.
  4. Dingerkus, G., & Santoro, E. D. (1981). Cornea regeneration in the Pacific giant octopus, Octopus dofleini, and the common octopus, O. vulgaris. Experientia, 37(4), 368-369.
  5. Jopling, C., Sleep, E., Raya, M., Martí, M., Raya, A., & Belmonte, J. C. I. (2010). Zebrafish heart regeneration occurs by cardiomyocyte dedifferentiation and proliferation. Nature, 464(7288), 606.
  6. Payzin-Dogru, D., & Whited, J. L. (2018). An integrative framework for salamander and mouse limb regeneration. International Journal of Developmental Biology, 62(6-7-8), 393-402.

Discussion

No comments yet.

Post a Comment

Instagram

  • by oceanbites 4 weeks ago
    Not all outdoor science is fieldwork. Some of the best days in the lab can be setting up experiments, especially when you get to do it outdoors. It’s an exciting mix of problem solving, precision, preparation, and teamwork. Here is
  • by oceanbites 2 months ago
    Being on a research cruise is a unique experience with the open water, 12-hour working shifts, and close quarters, but there are some familiar practices too. Here Diana is filtering seawater to gather chlorophyll for analysis, the same process on
  • by oceanbites 3 months ago
    This week for  #WriterWednesday  on  #oceanbites  we are featuring Hannah Collins  @hannahh_irene  Hannah works with marine suspension feeding bivalves and microplastics, investigating whether ingesting microplastics causes changes to the gut microbial community or gut tissues. She hopes to keep working
  • by oceanbites 3 months ago
    Leveling up - did you know that crabs have a larval phase? These are both porcelain crabs, but the one on the right is the earlier stage. It’s massive spine makes it both difficult to eat and quite conspicuous in
  • by oceanbites 3 months ago
    This week for  #WriterWednesday  on  #Oceanbites  we are featuring Cierra Braga. Cierra works ultraviolet c (UVC) to discover how this light can be used to combat biofouling, or the growth of living things, on the hulls of ships. Here, you
  • by oceanbites 3 months ago
    This week for  #WriterWednesday  at  #Oceanbites  we are featuring Elena Gadoutsis  @haysailor  These photos feature her “favorite marine research so far: From surveying tropical coral reefs, photographing dolphins and whales, and growing my own algae to expose it to different
  • by oceanbites 4 months ago
    This week for  #WriterWednesday  on Oceanbites we are featuring Eliza Oldach. According to Ellie, “I study coastal communities, and try to understand the policies and decisions and interactions and adaptations that communities use to navigate an ever-changing world. Most of
  • by oceanbites 4 months ago
    This week for  #WriterWednesday  at  #Oceanbites  we are featuring Jiwoon Park with a little photographic help from Ryan Tabata at the University of Hawaii. When asked about her research, Jiwoon wrote “Just like we need vitamins and minerals to stay
  • by oceanbites 5 months ago
    This week for  #WriterWednesday  on  #Oceanbites  we are featuring  @riley_henning  According to Riley, ”I am interested in studying small things that make a big impact in the ocean. Right now for my master's research at the University of San Diego,
  • by oceanbites 5 months ago
    This week for  #WriterWednesday  at  #Oceanbites  we are featuring Gabby Stedman. Gabby is interested in interested in understanding how many species of small-bodied animals there are in the deep-sea and where they live so we can better protect them from
  • by oceanbites 5 months ago
    This week for  #WriterWednesday  at  #Oceanbites  we are featuring Shawn Wang! Shawn is “an oceanographer that studies ocean conditions of the past. I use everything from microfossils to complex computer models to understand how climate has changed in the past
  • by oceanbites 5 months ago
    Today we are highlighting some of our awesome new authors for  #WriterWednesday  Today we have Daniel Speer! He says, “I am driven to investigate the interface of biology, chemistry, and physics, asking questions about how organisms or biological systems respond
  • by oceanbites 6 months ago
    Here at Oceanbites we love long-term datasets. So much happens in the ocean that sometimes it can be hard to tell if a trend is a part of a natural cycle or actually an anomaly, but as we gather more
  • by oceanbites 6 months ago
    Have you ever seen a lobster molt? Because lobsters have exoskeletons, every time they grow they have to climb out of their old shell, leaving them soft and vulnerable for a few days until their new shell hardens. Young, small
  • by oceanbites 7 months ago
    A lot of zooplankton are translucent, making it much easier to hide from predators. This juvenile mantis shrimp was almost impossible to spot floating in the water, but under a dissecting scope it’s features really come into view. See the
  • by oceanbites 7 months ago
    This is a clump of Dead Man’s Fingers, scientific name Codium fragile. It’s native to the Pacific Ocean and is invasive where I found it on the east coast of the US. It’s a bit velvety, and the coolest thing
  • by oceanbites 8 months ago
    You’ve probably heard of jellyfish, but have you heard of salps? These gelatinous sea creatures band together to form long chains, but they can also fall apart and will wash up onshore like tiny gemstones that squish. Have you seen
  • by oceanbites 9 months ago
    Check out what’s happening on a cool summer research cruise! On the  #neslter  summer transect cruise, we deployed a tow sled called the In Situ Icthyoplankton Imaging System. This can take pictures of gelatinous zooplankton (like jellyfish) that would be
  • by oceanbites 9 months ago
    Did you know horseshoe crabs have more than just two eyes? In these juveniles you can see another set in the middle of the shell. Check out our website to learn about some awesome horseshoe crab research.  #oceanbites   #plankton   #horseshoecrabs 
  • by oceanbites 9 months ago
    Feeling a bit flattened by the week? So are these summer flounder larvae. Fun fact: flounder larvae start out with their eyes set like normal fish, but as they grow one of their eyes migrates to meet the other and
WP2Social Auto Publish Powered By : XYZScripts.com