Confocal images of leech neurons cultured on FLAT, T2 and T4. (a–c) Leech neurons were grown on FLAT (a), T2 (b) and T4 (c) substrates and immunostained for tubulin-α (green) and actin (red); scale bars, 30 μm; inset, GR pattern direction. (d–f) Details of leech GCs developing on FLAT (d), T2 (e) and T4 (f); scale bars, 10 μm.