How moon jellyfish get about

January 23, 2020

With their translucent bells, moon jellyfish (Aurelia aurita) move around the oceans in a very efficient way. Scientists at the University of Bonn have now used a mathematical model to investigate how these cnidarians manage to use their neural networks to control their locomotion even when they are injured. The results may also contribute to the optimization of underwater robots. The study has already been published online in the journal eLife; the final version will appear soon.

Moon jellyfish (Aurelia aurita) are common in almost all oceans. The cnidarians move about in the oceans with their translucent bells, which measure from three to 30 centimeters. "These jellyfish have ring-shaped muscles that contract, thereby pushing the water out of the bell," explains lead author Fabian Pallasdies from the Neural Network Dynamics and Computation research group at the Institute of Genetics at the University of Bonn.

Moon jellyfish are particularly efficient when it comes to getting around: They create vortices at the edge of their bell, which increase propulsion. Pallasdies: "Furthermore, only the contraction of the bell requires muscle power; the expansion happens automatically because the tissue is elastic and returns to its original shape."

Jellyfish for research into the origins of the nervous system

The scientists of the research group have now developed a mathematical model of the neural networks of moon jellyfish and used this to investigate how these networks regulate the movement of the animals. "Jellyfish are among the oldest and simplest organisms that move around in water," says the head of the research group, Prof. Dr. Raoul-Martin Memmesheimer. On the basis of them and other early organisms, the origins of the nervous system will now be investigated.

Especially in the 50s and 80s of the last century, extensive experimental neurophysiological data were obtained on jellyfish, providing the researchers at the University of Bonn with a basis for their mathematical model. In several steps, they considered individual nerve cells, nerve cell networks, the entire animal and the surrounding water. "The model can be used to answer the question of how the excitation of individual nerve cells results in the movement of the moon jellyfish," says Pallasdies.

The jellyfish can perceive their position with light stimuli and with a balance organ. If a moon jellyfish is turned by the ocean current, the animal compensates for this and moves further to the water surface, for example. With their model, the researchers were able to confirm the assumption that the jellyfish uses one neural network for swimming straight ahead and two for rotational movements.

Wave-shaped propagation of the excitation

The activity of the nerve cells spreads in the jellyfish's bell in a wave-like pattern. As experiments from the 19th century already show, the locomotion even works when large parts of the bell are injured. Scientists at the University of Bonn are now able to explain this phenomenon with their simulations: "Jellyfish can pick up and transmit signals on their bell at any point," says Pallasdies. When one nerve cell fires, the others fire as well, even if sections of the bell are impaired.

However, the wave-like propagation of the excitation in the jellyfish's bell would be disrupted if the nerve cells fired randomly. As the researchers have now discovered on the basis of their model, this risk is prevented by the nerve cells not being able to become active again so quickly after firing.

The scientists hope that further research will shed light on the early evolution of the neural networks. At present, underwater robots are also being developed that move on the basis of the swimming principle of jellyfish. Pallasdies: "Perhaps our study can also help to improve the autonomous control of these robots."
-end-
Publication: Fabian Pallasdies, Sven Goedeke, Wilhelm Braun, Raoul-Martin Memmesheimer: From Single Neurons to Behavior in the Jellyfish Aurelia aurita, eLife, Internet: https://elifesciences.org/articles/50084

Media contact:

Fabian Pallasdies
Institute of Genetics
University of Bonn
Tel. +49-30-2093-98407
E-mail: fabianpallasdies@gmail.com

Prof. Dr. Raoul-Martin Memmesheimer
Institute of Genetics
University of Bonn
Tel. +49-228-739824
E-mail: rm.memmesheimer@uni-bonn.de

University of Bonn

Related Nerve Cells Articles from Brightsurf:

Nerve cells let others "listen in"
How many ''listeners'' a nerve cell has in the brain is strictly regulated.

Nerve cells with energy saving program
Thanks to a metabolic adjustment, the cells can remain functional despite damage to the mitochondria.

Why developing nerve cells can take a wrong turn
Loss of ubiquitin-conjugating enzyme leads to impediment in growth of nerve cells / Link found between cellular machineries of protein degradation and regulation of the epigenetic landscape in human embryonic stem cells

Unique fingerprint: What makes nerve cells unmistakable?
Protein variations that result from the process of alternative splicing control the identity and function of nerve cells in the brain.

Ragweed compounds could protect nerve cells from Alzheimer's
As spring arrives in the northern hemisphere, many people are cursing ragweed, a primary culprit in seasonal allergies.

Fooling nerve cells into acting normal
In a new study, scientists at the University of Missouri have discovered that a neuron's own electrical signal, or voltage, can indicate whether the neuron is functioning normally.

How nerve cells control misfolded proteins
Researchers have identified a protein complex that marks misfolded proteins, stops them from interacting with other proteins in the cell and directs them towards disposal.

The development of brain stem cells into new nerve cells and why this can lead to cancer
Stem cells are true Jacks-of-all-trades of our bodies, as they can turn into the many different cell types of all organs.

Research confirms nerve cells made from skin cells are a valid lab model for studying disease
Researchers from the Salk Institute, along with collaborators at Stanford University and Baylor College of Medicine, have shown that cells from mice that have been induced to grow into nerve cells using a previously published method have molecular signatures matching neurons that developed naturally in the brain.

Bees can count with just four nerve cells in their brains
Bees can solve seemingly clever counting tasks with very small numbers of nerve cells in their brains, according to researchers at Queen Mary University of London.

Read More: Nerve Cells News and Nerve Cells Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.