Ility to select synaptic targets come from serial electron microscopy reconstruction studies. A reconstruction of an arbor from a retinal ganglion axon in the lateral geniculate nucleus revealed that it only selects 4 cells as synaptic partners from a total of 43 contacting cells (Hamos et al. 1987). A systematic survey of the Caenorhabditis elegans nervous system showed that one out of six contac