Axonal projections from the LGN in the ventral coculture. A, DiI-labeled axons forming branches at 1 week in vitro. B, Another LGN axon similar to A. White arrows represent branching points. C, Axons without branches reach layer 1 or grow toward the pial surface with a growth cone. White arrowheads indicate the growing axons in the middle or deep layer. D, Axonal branching after 2 weeks in culture. Scale bar (shown in A), 250 μm in A–D.E, The distribution of branching points.Arrows indicate the putative layer 4 borders.