ABSTRACT
Although damaged mammalian peripheral nerves apparently possess considerable potential for axonal growth, functional recovery is often very poor after peripheral nerve trauma because the regenerating fibers show only a weak preference for their original target and, as a consequence, many inappropriate synapses may be formed. This chapter focuses on the cockroach as an experimental model for studying cellular consequences of nerve damage. Although a neuron is a functional entity, axonal, dendritic, and somatic responses are discussed separately since each may be considered a different functional compartment within the neuron itself. The axons of insect motoneurons generate a profusion of new processes within 3 to 4 days of peripheral nerve injury. Initial growth apparently shows little directional preference so that, at relatively short postoperative periods, muscles may receive branches from appropriate and inappropriate motoneurons. The dendritic arbor of adult cockroach motoneurons is hardly altered by lesions such as nerve crushes that allow subsequent rapid recovery.
