The “wireless” brain network of a roundworm mapped in detail

Neurobiologists have succeeded in mapping the “wireless” network of the roundworm C. elegans in detail. KU Leuven, which contributed to the studies, announced this on Wednesday. The network consists of small proteins, called neuropeptides, that ensure communication between brain cells.

One of the most well-known forms of communication in the brain is synaptic signal transmission: neurons transmit electrical stimuli to each other, using neurotransmitters. However, this signal transmission only occurs between neurons that are physically connected via synapses.

However, neurons have another way to communicate, which works using neuropeptides. Neuropeptides were discovered about 50 years ago as small proteins in the body. One well-known example of a neuropeptide is oxytocin, also known as the cuddle hormone.

It has recently been discovered that neuropeptides are also found in the brain: they form an “alternative” communication network, where sending and receiving neurons do not need to be physically connected. Therefore, the neuropeptide network is also called the “wireless” brain network.

Synaptic signal transduction was first mapped 40 years ago in C.elegans. However, this never happened before the advent of the “wireless” neuropeptide network. Neurobiologists from the University of Leuven, in collaboration with colleagues from Cambridge, London and Paris, have been able to do this for the first time.

“We also used the roundworm C. elegans for this purpose,” says neurobiology professor Isabel Betts (KU Leuven-Leuven Brain Institute). “The worm lends itself well to genetic brain research. But in the end, our research took about 8 years: neuropeptide interactions are not anatomically visible. You need special research techniques to map them.”

The neuropeptide map shows all interactions between 302 C. elegans neurons, representing more than thirty thousand interactions. In the first step, we mainly worked at the molecular level and looked for which neuropeptides belong to which receptors. These results were published in the scientific journal Cell Reports. In the second step, published in the journal Neuron, the researchers combined the ideas into an overall map.

Thanks to the researchers’ work, the functions of neuropeptides can also be better studied in humans. “We know that some neuropeptides, which play a role in reproductive or learning processes, for example, show similarities or even universality between roundworms and humans,” says Bates. “Our map makes it easier to study. We’re also working on new insights into how neuropeptides as a whole work together.”