Induced regeneration of neurons imaged in living fish

The ability to image nerve cells in the live fish allows us to explore ways to induce the regeneration of their processes after injury. We can label a single Mauthner neuron,which initiates the escape behavior, in the living fish (bright red in image above).

 

If the spinal cord of the fish is severed, the large axons of the Mauthner neuron typically do not regenerate (above).

 

We have shown that by applying the molecule cyclic AMP it is possible to induce the nerve cell to grow again and cross the damaged spinal cord to reconnect and restore the ability of the fish to escape. After treatment, the axon (above) grows down the spinal cord to form a much longer axon, more similar to the normal one.

 

This is a movie of a growing axon that has been induced to regenerate. The transparency of the fish allowed the first imaging of induced regeneration and functional recovery in a living vertebrate. Zebrafish thus offer a powerful model for testing strategies for restoring function after spinal injury in humans.