EphB receptors differ in signals required for MF pruning. (A) Neurotrace dye–labeled pattern of CA3 pyramidal cells in PW3 WT, EphB1^−/−, and EphB1^LacZ/LacZ mice. Calbindin staining showed that the IPB axon–penetrated CA3 pyramidal neurons layer are much longer in EphB1^−/− mice compared with WT or EphB1^LacZ/LacZ mice. White brackets delineate IPB length, and distance between white arrowheads delineates the IPB length in CA3 pyramidal neurons. (B) The ratio of IPB length to the length from hilus to curvature of CA3 area and IPB length within CA3 pyramidal neurons in WT, EphB1^−/−, and EphB1^LacZ/LacZ mice were quantified. n = 5–6 mice per group. (C and D) Calbindin staining for PW3 WT, EphB2^−/−, EphB2^LacZ/LacZ, and EphB2^K661R/K661R mice. The length ratio of IPB and IPB length in CA3 pyramidal neurons are much longer in EphB2^−/−, EphB2^LacZ/LacZ, and EphB2^K661R/K661R mice compared with WT mice. n = 4–5 mice per group. (E and F) Calbindin staining for PW3 Lnx1^−/− and Lnx1^−/−; EphB1^LacZ/LacZ mice. No difference was observed in IPB axons between Lnx1^−/− and Lnx1^−/−; EphB1 ^LacZ/LacZ mice. n = 5 mice per group. (G and H) Calbindin staining for PW3 EphB2 ^F620D/F620D, Lnx1^−/−, and Lnx1^−/−; EphB2 ^F620D/F620D mice. The aberrant IPB axons in Lnx1^−/− mice were rescued in Lnx1^−/−; EphB2 ^F620D/F620D mice. n = 5–6 mice per group. Bars, 100 µm. Means ± SEM; one-way ANOVA with Tukey’s post hoc test (B, D, F, and H); *, P < 0.05; **, P < 0.01; ***, P < 0.001.