New directions in neuroregeneration.

Neurons in the adult mammalian central nervous system (CNS) do not spontaneously regenerate their axons after injury. Despite significant progress in the field of axonal regeneration, effective therapeutic strategies to promote functional recovery after injury are not available. The development of novel therapeutics will require further insights into the intrinsic and extrinsic mechanisms that restrict regeneration in the adult CNS. It is equally important that the mechanisms mediating the restoration of axonal connectivity must be determined. This review summarises the known molecular mechanisms of neurite outgrowth inhibition after CNS injury and provides new insights into the potential future direction of neuroregeneration research.