Ann Rose Bright and Inbal Shainer win Young Scientist Award

What shapes a neuron's form, function and how quickly it matures? For this year's two Young Scientist Award winners, part of the answer lies beyond the genes a cell switches on, in where and when it is born.

To the point:

• Two young scientists honored: Ann Rose Bright and Inbal Shainer have received this year's Young Scientist Award, which recognizes outstanding published studies by the Institute's early-career researchers.
• Late neurons catch up: Bright and her colleagues found that inhibitory neurons born late in development mature much faster than early-born ones, a pace set in part by the transcription factor NFIB.
• Place matters, not just genes: Shainer and her colleagues show that two neurons with almost identical gene activity can still differ in shape and function, depending on where each one sits in the brain.

Nerve cells, or neurons, carry signals through the brain and body, underlying everything from movement and sensation to thought and memory. They come in extraordinary variety, yet all arise from progenitors – the dividing cells of the developing brain. Since every cell carries essentially the same DNA, what each neuron becomes, and how quickly it matures, owes much to which of its genes are switched on. But this can also be influenced by a range of other factors, including where the cell sits in the brain and when, in development, it is born.

This year's Young Scientist Award honors two early-career scientists whose research at the Max Planck Institute for Biological Intelligence (MPI-BI) has explored these wider influences. The €1000 prize recognizes outstanding published studies based on work carried out at the Institute, and celebrates the vital role of early-career scientists in advancing science. Its fund is kindly endowed by the Elisabeth and Helmut Uhl Foundation.

How late-born neurons catch up

The brain's neurons are not all born at once: some appear early in development, others much later, with less time to mature. Ann Rose Bright and her multidisciplinary team in Christian Mayer's group explored how latecomers can still fit in without unbalancing the brain's complex networks. Their work focused on inhibitory neurons, the crucial nerve cells that restrain and shape the activity of others.

The study, published in Nature Neuroscience in July 2025, profiled individual cells in mice at successive stages of maturation, using techniques that read them at several molecular levels. Birth timing, the researchers found, changes not which types of inhibitory neuron are produced, but how quickly they mature: those born later develop much faster than early-born ones.

“We asked: how does time work in all of this?” Bright explains. “We found that late-born neurons catch up by maturing faster, with those born at the end of neurogenesis speeding up their whole developmental process to be ready in time.”

Without that catch-up, the researchers suggest, earlier-born neurons could end up with far more connections than later-born ones, throwing the network off balance. The team traced that faster pace to a transcription factor called NFIB, a protein that controls the activity of genes and helps late-born cells read key stretches of DNA at the right moment.

“What amazes me is how precise and synchronized the process is,” says Bright. “Many of the systems that guide development are the same ones affected in neurodevelopmental disorders, so understanding how they work in health could, in time, help scientists make sense of disease. Receiving this award is a great acknowledgment of the efforts of our wonderful team, and it gives me a lot of motivation to pursue exciting new questions arising in this field.”

Where a neuron sits shapes what it is

To understand the brain fully, it is important to know its cell types, which scientists classify largely by the genes that are switched on inside them. But in the zebrafish visual system, that is not the whole story. Two neurons can switch on almost the same genes yet turn out differently, and Inbal Shainer and her team showed that, as well as gene activity, a neuron's position within the brain tissue can shape its form and function.

Published in Nature in February 2025, the team's study profiled the optic tectum, the main visual center of the zebrafish brain. They grouped the tectum's neurons into types by their gene activity, then used calcium imaging to link each cell's molecular identity to how it behaved and where it sat.

“Even within nerve cells that express genes almost identically, we saw a real variety of shapes and functions,” says Shainer, who carried out the work as a postdoctoral researcher in Herwig Baier's department. “Aside from genetics, one of the main things that determines that is where the cell sits within the tissue, and this position is closely tied to when the neuron is born during development. Defining cell types by both their position and their genes opens up new ways of thinking about them across the nervous system, so that, taken together, that information can be far more predictive of what role a cell is playing.”

Now an assistant professor at the Technion – Israel Institute of Technology in Haifa, Shainer is furthering her research on how the brain translates visual information into behavioral decisions.

“I love the zebrafish as a model system as you can literally see the brain in action under the microscope,” she says. “MPI-BI has an incredible scientific infrastructure and amazing people to collaborate with, ask questions, solve problems and really push things forward – my postdoc gave me the best training I could have asked for. The award is an amazing recognition, and it is an incredibly nice feeling to receive it.”

[AG]