Glowing nerve cells reveal how the brain works

A mouse brain is as big as a hazelnut and contains just over 70 million nerve cells. But how these nerve cells are linked to each other has long been unclear.

Researchers at the Janeila Research Campus in Washington, using a special technology, have made nerve cells luminescent and have therefore been able to follow individual nerve cells' path through the mouse brain.

Now they have mapped just over a thousand individual nerve cells and how they are linked to each other. The pictures show that the so-called axon of a nerve cell, the nerve thread itself, can extend over the entire brain.

Thus, a signal from a single nerve cell can branch out and reach a large number of cells scattered over large parts of the brain.

"The findings show that we have greatly underestimated how complicated the brain network is," says Henrik Jörntell, a neuroscientist at Lund University.

The new knowledge about the long-distance contacts of the brain can explain how part of the brain can take over the function from another part.

- It makes the brain more insensitive to injury than we previously thought. You can remove part of the brain and nothing needs to happen, says Henrik Jörntell.

This research is done on mice but can also explain how the human brain works, since all mammalian brains are structured in a similar way.

The big difference is that our brain has extremely many more nerve cells than any other animal. Today, the human brain is estimated to consist of 86 billion nerve cells.

The study is published in Cell.