Comb Jelly’s Bizarre Nervous System Finally Visualized

About the episode

Comb jellyfish are wonderful transparent sea creatures that have been swimming in our oceans for 600 million years. Their eight long thin comb-like ribs can shine in beautiful colors. What do they have? A bizarre nervous system, which has now been properly visualized for the first time.

Our own nervous system is made up of individual cells that communicate with each other via synapses: contact points where signals can pass from one cell to another. The idea has long been that only one pattern has emerged in evolution, which has been the pattern for the nervous system of all animals living today. Except, the jellyfish combs.

The animal was already known to deviate from it, but studying the nervous system of these small, vulnerable marine animals simply proved too difficult. Using a 3D electron microscope, researchers have now successfully imaged it in day-old American comb jelly.

Comb jellyfish have a nervous system that does not consist of individual neurons, but of fused networks of neurons. Possibly, but not yet certain, this is proof that there is more than one model for nervous systems. But more research is definitely needed. If only because we hardly know how signals can be sent in such a network without synapses.

Learn more here: Discovery challenges our understanding of nervous systems and their evolution.