Damage Control and Recovery

Abstract

Following injury to its axon, a neuron undergoes a stereotyped series of changes that play an important role in its ability to regrow the axon. Peripheral neurons and motoneurons (whose axons travel in the periph- ery) are often quite successful at axon regeneration. Likewise, inter- neurons in the CNS of lower vertebrates such as fishes and frogs are frequently able to re-establish synaptic connections after axon transec- tions. In contrast to these success stories, and much to the chagrin of physicians who treat patients with CNS damage, axon regeneration is insubstantial at best within the bounds of the mature human CNS. Let’s examine the changes that occur when neurons are injured, the putative reasons why central neurons are so sadly incompetent at regeneration, and what might be done to help them along.