Scientists have discovered a way to read the thoughts of jellyfish
Using clever genetic manipulation, the neurons of a tiny species of transparent jellyfish can now be observed working together to perform complex autonomous movements, such as grabbing and eating prey.
Clytia hemisphaerica is an ideal model for studying this behavior. Since this species of jellyfish is very small (less than a centimeter in diameter), their entire nervous system fits easily under a microscope. The genome is also quite simple, and the transparent body contains only about 10,000 neurons, making it easy to track neural messages.
When researchers genetically engineered the jellyfish C. hemisphaerica so that its neurons glow when activated, they discovered "an unforeseen degree of structured neuronal organization".
The nervous system of jellyfish was formed over 500 million years ago and has not changed much since then. Compared to the brains of modern animals, the neurons in these "living fossils" are much simpler. There is no centralized system coordinating all the movements of this creature, so how does it manage to do anything?
A new study suggests that C. hemisphaerica’s neurons are arranged in an umbrella-like network that mimics its body exactly. These neurons then divide into slices, almost like a pie. Each tentacle on the edge of the jellyfish’s bell is connected to one of these lobules. So when the jellyfish’s arms detect and capture prey, the neurons in that particular lobule fire in a specific sequence.
First, the neurons at the edge of the pie send messages to the neurons at the center, where the https://fr.opay.com.ng/page-coque-mobile-3 jellyfish’s mouth is. This causes the edge of the pie to turn inward towards the mouth, dragging the tentacle along with it. In this case, the mouth, in turn, "directs" towards the incoming food.
To see how the neurons that control the mouth interact with the neurons that control the bell of the jellyfish, and vice versa, the researchers began to surgically remove certain parts of the body. When jellyfish mouths were removed from the equation, the creatures kept trying to transfer food from their tentacles into non-existent mouths. And even when the jellyfish’s tentacles were removed, chemical extracts from the shrimp introduced into the aquarium could still cause the mouth to turn towards the food source.
The results obtained suggest that certain forms of jellyfish behavior are coordinated by various groups of functionally organized neurons located around the circumference of the umbrella. For example, the network of neurons connecting the jellyfish’s bell to its mouth could also be connected to the digestive system.
But the most interesting thing was that when the jellyfish in the study were deprived of food for a long time, they captured prey faster than when they were not so "hungry". This indicates some kind of neural feedback that lets the jellyfish "know" that it needs to fill its digestive system, putting other specific "nutrients" on high alert.