Many forms of brain and spinal cord (CNS) damage cut axons. ... Axon regeneration in the CNS fails for two reasons. First because the environment surrounding CNS lesions is inhibitory to axon growth, and second because most CNS axons only mount a feeble regeneration response after they are cut.

What prevents regeneration within the CNS?

The two major classes of CNS regeneration inhibitors are the myelin-associated inhibitors (MAIs) and the chondroitin sulfate proteoglycans (CSPGs). These molecules limit axon regeneration, and, by interfering with their function, some degree of growth in the adult CNS is achieved.

Is regeneration of CNS is possible?

The mammalian CNS is usually not capable of regeneration. However, conditioning dorsal root ganglion neurons by first lesioning their peripheral axons allows for regeneration of their central axons later on within the spinal cord.