Helping neurons find their way

Variations in the spatial distribution of cellular signaling molecules provide the information needed to steer neuron growth within the brain

As the brain develops, neuronal axons extend outward in search of other neurons, all the while receiving ‘directions’ from the extracellular environment in the form of chemical signals that indicate when and where these growing axons should turn. For example, axons exposed to a gradient distribution of nerve growth factor (NGF) protein will automatically steer in the direction of highest NGF concentration.

“NGF is one of the most extensively studied molecules that direct axon elongation,” explains Hiroyuki Kamiguchi of the RIKEN Brain Science Institute in Wako. “However, it has remained unclear for a long time how axons change the direction of elongation in response to NGF.”