The possible role of “sibling neurite bias” in the coordination of neurite extension, branching, and survival

In this review we consider a novel mechanism, "sibling neurite bias," which may explain aspects of the coordination of elongation, branching, and resorption among different neurites growing from the same neuronal cell body. In this model, growing neurites which incorporate structural precursors at higher rates would deplete the cellular pool of precursors available to their "sibling" neurites; neurites would compete for survival, but in addition they would bias each other's behavior during active growth. Evidence is reviewed that "sibling neurite bias" may contribute to the establishment and stabilization of specific neural connections. Specific examples examined include the loss of polyinnervation at the developing neuromuscular junction, contextual mapping in the retino-tectal system, and selective neurite growth patterns and synaptic connections in nerve tissue culture model systems.