Fig. 4. A specific position of the rat hippocampal slice culture is required to induce a compact cell layer in the reeler dentate gyrus. Two reeler cultures (rl–/–1 and rl–/–2) are co-cultured with a rat hippocampal slice. A compact cell layer (arrow) has only formed in rl–/–1, which was co-cultured next to the outer molecular layer of the rat dentate gyrus. In rl–/–2, which was cultured next to the stratum oriens of CA1, the reeler-specific loose distribution of neurons in the dentate gyrus is retained (arrowhead). Dashed lines represent borders between cultures. Scale bar: 200 µm.