Moon jellyfish (Aurelia aurita), which are present in almost all of the world’s oceans, are now being studied by researchers to learn how their neural networks function. By using their translucent bells that measure from three to 30 centimeters, the cnidarians are capable of moving around very efficiently.
The lead author of the study is Fabian Pallasdies from the Neural Network Dynamics and computation research group at the Institute of Genetics at the University of Bonn.
“These jellyfish have ring-shaped muscles that contract, thereby pushing the water out of the bell,” Pallasdies explains.
The efficiency of their movements comes from the ability of the moon jellyfish to create vortices at the edge of their bell, in turn increasing propulsion.
“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,” continues Pallasdies.
The group of scientists has now developed a mathematical model of the neural networks of moon jellyfish. It is used to investigate the neural networks and how they regulate the movement of the moon jellyfish.
Professor Dr. Raoul-Martin Memmesheimer is the head of the research group.
“Jellyfish are among the oldest and simplest organisms that move around in water,” he says.
The team will now look at the origins of its nervous system and other organisms.
Jellyfish have been studied for decades, and extensive experimental neurophysiological data was collected between the 1950s and 1980s. The researchers at the University of Bonn used the data to develop their mathematical model. They studied 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.
Moon jellyfish are able to perceive their location through light stimuli and with a balance organ. The animal has ways of correcting itself when turned by the ocean current. This often involves compensating for the movement and going towards the water surface. The researchers confirmed through their mathematical model that the jellyfish use one neural network for swimming straight ahead and two for rotational movements.
The activity of the nerve cells move throughout the jellyfish’s bell in a wave-like pattern, and the locomotion works even when large portions of the bell are injured. Scientists at the University of Bonn are now able to explain this 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.”
The moon jellyfish is the latest species of animals in which neural networks are being studied. The natural environment can provide many answers to new questions revolving around neural networks, artificial intelligence, robotics, and more. Currently, underwater robots are being developed based on the swimming principles of jellyfish.
“Perhaps our study can help to improve the autonomous control of these robots,” Pallasdies says.
The scientists hope that their research and ongoing work will help explain the early evolution of neural networks.