Regeneration of specific neuromuscular connections in the crayfish. I. Pattern of connections and synaptic strength.

Development and regeneration of the escape reflex in the earthworm, Eisenia foetida

“…Since formation of these connections was always accompanied by the functional restoration in sensory and motor pathways, it may be inferred that peripheral target tissues were successfully reinnervated and that specificity of target selection by transplanted sensory and motor neurons was broad enough to include serially or laterally homologous tissues from different body regions. Similarly, previous studies have indicated a specificity of reconnections between regenerating motor neurons and serially homologous, as well as laterally homologous, target muscles in arthropods (Young, 1973;Bate, 1976;Fourtner et al, 1978;Ely and Velez, 1982;Hunt and Velez, 1982).…”

Structure of allotransplanted ganglia and regenerated neuromuscular connections in crayfish

“…This included cutting all the nerve roots close to the ganglia except for the superficial nerve of the third root on one side of the third ganglion. This nerve, which carries the motor axons to the superficial flexor muscles, was carefully dissected along its length and removed with a few muscle fibers still attached to it; the presence o f a few intact neuromuscular connections is necessary for the transplanted motoneurons to regenerate to their host target muscle fibers (Ely and Velez, 1982). The fourth ganglion was included in the transplant because it contains the soma for one of the excitor axons to the superficial muscle in the third abdominal segment.…”

“…The ability of crayfish motor axons to regenerate connections to muscle fibers has been used by Velez and his collaborators to address the issue of how neurons contact specific target cells (Ely and Velez, 1982;Velez, 1982, 1989a,b). For these regenerated connections.…”

Allotransplanted nerves regenerate inhibitory synapses on a crayfish muscle: Possible postsynaptic specification

“…Pioneering studies by Velez and his collaborators established that the five excitatory and single inhibitory neuron formed synaptic connections that varied in strength in a regional manner across the 40 muscle fibers (Velez and Wyman, 1978). After the SFM nerve was transected and the original innervation had degenerated, the regenerating proximal ends of the motor axons formed a pattern of synaptic connections similar to the original (Ely and Velez, 1982). Such a high degree of specificity of synaptic reconnections occurred despite drastic manipulation of the muscle (Hunt and Velez, 1982;Clement et al, 1983;Hunt and Velez 1989a) or nerve (Goransson et al 1988;Worden et al 1988;Hunt and Velez 1989b).…”