The Patterning of Neuronal Connections1

SYNOPSIS. The final level of development in the vertebrate nervous system concerns the patterning, or modelling, of the connections of the postmitotic neurons at target tissues. The growth of target tissue and the sprouting of newly-arrived axons is followed by a regulated distribution of the sprouts, and often the development of specific contacts (synapses). Usually there are more sprouts than can be accommodated; the result is competition for …