For a period shortly before and after birth, we undergo “an exuberant burst of synapse formation,” in which the brain wires itself: the neurons sprout microscopic branches, called axons, that reach out in search of tiny nubs on other neurons, called dendrites. When axon meets dendrite, a synapse is formed. In order for some axons to find their target dendrites they must travel vast distances to complete the connections that make up our neural circuitry
