ABSTRACT
When axons arrive at a target they compete with each other to form synapses–synaptogenesis. Synapse formation has been most extensively studied at the neuromuscular junction. Both muscle fibers and axons degenerate to leave the synaptic basal lamina and the Schwann cells that encapsulated the axon. The earliest event in synapse elimination is a downregulation in the number of nicotinic acetylcholine receptors. Central synapses have poorly developed basal lamina and although agrin is present neither muscle specific kinase nor rapsyn are present in brain. Developmental plasticity has been extensively studied in the visual system. Plasticity in the primary visual cortex, V1, is responsible for the formation of ocular dominance columns and hence for the development of binocular vision. N-methyl-D-aspartate receptors are implicated in visual system plasticity. During the critical period for binocular wiring of the visual system, the effect of monocular deprivation can be partly reversed by restoring binocular vision.
