Axons are the long fibres that connect one nerve cell with another and carry electrical communication between them. If these fibres degenerate, nervous function ceases resulting in neurodegenerative diseases such as Alzheimer's disease, motor neuron disease and multiple sclerosis. In many nervous disorders, the degeneration of the fibres precedes death of the cell from which they arise, but in the central nervous system the fibres cannot regenerate even if the cell survives. Thus, it is essential to understand and eventually intervene in axon degeneration mechanisms. We have identified a gene that can delay axon degeneration tenfold in mice, rats and flies, and have now found a chemical treatment that blocks its action. The aim of this project is to understand the basis of this block, and to shed light on how one part of a nerve cell signals to other parts that damage has taken place.