Figure 1

Effects of Ferret VAChT-Sap treatment on retinogeniculate refinement. At postnatal day 10 (P10), retinal afferents from the left eye (green in all images) and right eye (magenta) have undergone extensive remodeling to form contralateral layers A and ipsilateral layers A1 (a, left panels) segregated from one another in the two dLGNs (a, left ‘Merged’ panels). Treatment with Ferret VAChT-Sap does not affect the normal refinement process in cases where the degree of SAC ablation is symmetric in the two eyes (a, center panels). Binocular overlap and the overall size of the ipsilateral projection to both dLGNs is normal following Ferret VAChT-Sap treatment when the ablation is symmetric in the two eyes (b, c). In cases where treatment with Ferret VAChT-Sap leads to asymmetric SAC ablation in one eye versus the other, the eye with the greater number of SACs develops an expanded projection in the two dLGNs (a, right panels; b, c, quantification). Binocular overlap is greater in the dLGN receiving the expanded ipsilateral projection compared with the dLGN receiving the contracted ipsilateral projection (c). In all cases of Ferret VAChT-Sap treatment, the number of SACs is significantly reduced compared to saline controls (d). C1, ipsilateral layer; dLGN, dorsal lateral geniculate nucleus; MIN, medial intralaminar nucleus; OT, optic tract; SAC, starburst amacrine cells; vLGN, ventral lateral geniculate nucleus; W, wing of the geniculate. Quantification shows mean values + SEM; two saline controls, four symmetric Ferret VAChT-Sap-treated animals, and ten asymmetric VAChT-Sap-treated animals were included in the analysis. Statistics reflect a one-way ANOVA with Bonferroni post-hoc correction (*P <0.05, **P <0.01, ***P <0.001). All group mean comparisons with no corresponding asterisks did not reach significance.