Laying Down Axons

To send a message between nerve cells, a signal needs to leave the terminal of one, cross the space called a synapse, before arriving at the next. Like a train following the tracks to reach the correct destination. These tracks are laid down when our brains are developing, but what controls exactly where was unclear. Researchers have revealed in fruit flies that interactions between axons – nerve fibres – in the central nervous system contribute to where synapses are positioned. Pain-sensing neurons (magenta) normally form a ladder-like arrangement (the rails and sleepers), whereas touch-sensing neurons (green) mainly form along the rails but don’t cross the middle (top panel). Each type of neuron has their own zone. Researchers disrupted the ability of pain-sensing neurons to form their usual pattern and found that more touch-sensing neurons could now cross the middle (bottom panel), showing how axons work together to lay down the correct patterns.

Written by Sophie Arthur

Sophie Arthur

former Science Communications Officer MRC LMS

Formerly a stem cell biologist, Sophie has since moved into science communication working at the MRC LMS. She also writes an award winning science and education blog Soph talks science.

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• Image from work by Samantha E. Galindo and colleagues
• Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY, USA
• Image originally published with a Creative Commons Attribution 4.0 International (CC BY 4.0)
• Published in Development, March 2023