This lesson is a basic introduction to on axon growth and guidance. Axons, the projections from brain cells (neurons), grows away from the cell body to make connections between areas of the nervous system that need to communicate. One of the best characterized systems in the brain of axon growth and guidance is part of the visual system. Cells in your retina--- retinal ganglion cells – have to make very precise connections to another area of the brain-- the superior colliculus. The retina compresses the visual world around you, and passes that representation to other parts of your brain, including the superior colliculus (SC). The SC maintains a topographic map of the retinal inputs. This map is created through a gradient of guidance molecules. The main point to get across is that molecular tags on projecting axons and in their target zones determine the specificity of axonal connections.