Retinogeniculate projections from the two eyes in P10 and P30 WT and NP1/2 KO mice. Except for scale, conventions are as in Figure 5. A, In P10 WT mice, inputs from the two eyes are segregated; a region in the dorsomedial dLGN is devoid of label from the contralateral eye. This region is occupied by the axons from the ipsilateral eye. Note also that axons from the ipsilateral eye are always restricted to the dorsomedial dLGN. B, C, In P10 NP1/2 KO mice, axons from the two eyes are still intermingled in the dLGN. The contralateral projection fills the entire dLGN; there is no gap present. B, In approximately half of the P10 NP1/2 mice examined, the ipsilateral eye projection comprises a single termination zone, but this zone appears larger than in WT mice. C, In the other cases, the ipsilateral eye axons are especially widespread. Despite these slight differences in patterning of the ipsilateral eye projection, in all P10 NP1/2 cases examined (n = 6 mice), the contralateral eye projection fills the entire dLGN, and thus axons from the two eyes always intermingled with those from the opposite eye, which is abnormal for mice of this age (compare bottom panels). D, Retinal inputs to the dLGN of P30 WT mice are segregated. E, Binocular inputs to the dLGN of P30 NP1/2 KO mice are also segregated (no yellow in bottom panel); however, note that compared with P10 or P30 WT mice, the ipsilateral axons are widespread and not restricted to the dorsomedial dLGN in NP1/2 KO mice (middle panels). Scale bars, 200 μm. F, Quantification of the percentage of the dLGN receiving overlapping inputs from the ipsilateral eye in WT versus NP1/2 KO mice at P10 and P30. P10 NP1/2 KO mice exhibit significantly more overlap in the dLGN than P10 WT mice, regardless of threshold. P30 KO mice have retino-dLGN inputs that are segregated to a degree similar to that of WT mice P10 and older (no significant differences observed at any threshold) (n = 4 P10 WT mice; n = 8 P10 NP1/2 KO mice; n = 2 P30 NP1/2 KO mice; Student's t test; ±SEM; ∗p < 0.0001). All images are shown at the same threshold level (15% above background; see Materials and Methods).