Repair of nerves in the adult central nervous system is one of the holy grails of neurology: the adult mammalian CNS is unable to regenerate axons - the extended parts of neurons that form nerve fibers - once they are severed or damaged.

One reason for the failure may be scarring of the supporting extracellular matrix of glial tissue, rather than inhibition by myelinated white matter, as is commonly believed. Now, a new report in Nature implies that the adult nervous system has vast potential to repair itself.