Retinogeniculate projections from the two eyes in P4 WT and P4 NP1/2 KO mice. A, B, Photomicrographs of the contralateral eye projections (top panels), ipsilateral eye projections (middle panels), and the locations in which they overlap (bottom panels) in the dLGN of WT (A) and NP1/2 KO (B) P4 mice. In both the P4 WT and P4 KO mice, axons from the two eyes are extensively intermingled in the dLGN. Coronal plane is shown; dorsal is up and medial is to the right of each panel. IGL, Intergeniculate leaflet; OT, optic tract. The boundary of the dLGN is shown with the dashed line. Scale bar, 100 μm. C, Multi-threshold analysis of the percentage of the dLGN containing overlapping axons from both eyes in the dLGN (see Materials and Methods) of WT and NP1/2 KO mice revealed no significant differences in overlap at any threshold (n = 3 mice were analyzed per genotype at P4; Student's t test; ±SEM). All images are shown at same threshold level (15% above background; see Materials and Methods).