Fig. 1. Intra-retinal axon targeting. (A) To facilitate analysis and observation, retinas were flat-mounted by making a few cuts at the edge. (B) The cells in the GCL and the axons in OFL can be stained and analyzed on the flat-mount retina with the vitreal side upwards. (C) Retinal ganglion cells in ganglion cell layer (GCL) extend axons to optic fiber layer (OFL) where they project towards the optic disc (OD) at the center of the retina.