(A–I) Retino- (A, D, G) and cortico- (C, F, I) collicular maps generated by the 3-step Map alignment model in WT (A, C), Efna3KI/KI (D, F) and Efna3KI/+ (G, I) after n = 20 runs and 107 iteration/run. The parameters used for the retino-collicular modelling in the three genotypes are identical. Translated retinal Efn-As gradients (% of retinal expression: Efna2 = 100%, Efna3 = 100% and Efna5 = 80%) into the SC in WT (B), Efna3KI/KI (E) and Efna3KI/+ (H). Red lines in (C, F, I) represent the linear regression. Variability of the WT map in (C) is calculated by σWT = 2.18% (n = 20 runs). Grey lines in (F, I) represent the exclusion parameter (EP) corresponding to EP = σWT + ΔSexp: EPKI/KI = 15.18%, EPKI/+ = 9.18%. (J) Dot plot representation of the percentage of duplicated cortico-collicular projections (observed versus theoretical) for n = 20 runs in Efna3KI/KI (experimental = 47%, n = 9 animals; theoretical mean = 46.1%, ±95 %CI = 1.2%, one sample t-test, t = 1.42, 19 d.f., p = 0.17) and Efna3KI/+ (experimental = 43%, n = 7 animals; theoretical mean = 41.4%, ±95 %CI = 2.4%, variables are normally distributed, one sample t-test, t = 1.28, 19 d.f., p = 0.22) (theoretical Efna3KI/+ vs Efna3KI/KI, two-sample t-test, t = 3.4, 38 d.f., ***p = 0.0016). N, nasal; T, temporal; L, lateral; M, medial; R, rostral; C, caudal.