Melanopsin-dependent light responses of CRH+ ACs mature after eye opening. A, Melanopsin-dependent voltage responses of CRH+ ACs at four developmental time points. From top, mean (black) ± SEM (gray) of melanopsin-dependent light responses across CRH+ ACs at P9-P10 (n = 11), P11-P12 (n = 11), P13-P16 (n = 14), and P28-P32 (n = 15) (Φstim = 1.5 × 1017 Q cm−2 s−1). B, C, Peak (B) and sustained (C) voltage responses in CRH+ ACs shown in A. D, Confocal micrographs showing morphological development of CRH+ AC neurites at P10 (D1), P12 (D2), P16 (D3), and P28 (D4). Images are projections of ∼20 consecutive slices of a z stack (0.41 µm spacing). E, F, Neurite arbor diameter (E) and total neurite length (F) of CRH+ ACs (n = 16, n = 16, n = 18, and n = 18) at time points studied in A-C. **p < 0.01. ***p < 0.001.