Figure 2: The upregulation of IGF-1 expression in EE animals mediates the effects of enriched experience on adult VC plasticity. (a) Analysis of gene expression by RT-PCR revealed that IGF-1 and IGFbp5 expression increased in the VC of EE animals after 2 days of MD with respect to SC animals similarly treated ( for both experimental groups; t-test; respectively, and ). In contrast, no modifications of either IGF1-R (t-test; ) or IGFbp3 (t-test; ) expression were detected. (b) The expression of IGF-1, IGF-1R, IGFbp5, and IGFbp3 in the VC was not different between EE animals monocularly deprived for 7 days and SC rats similarly treated. (c) JB1 infusion prevented the OD shift induced by MD in EE animals: no difference in C/I VEP ratio between normal animals (Nor+MD; , 2.67 ± 0.15) and EE rats treated with JB1 subjected to MD detected (EE+JB1; ; 2.37 ± 0.09; One-way ANOVA, post hoc Holm Sidak method), while monocularly deprived EE animals (EE+MD; ; 0.99 ± 0.07) and EE rats treated with vehicle (EE+Veh; ; 1.08 ± 0.05) showed an OD shift in favor of the open eye (One-way ANOVA, = 46.48, , post hoc Holm Sidak method). (d) Coupling enriched experience with IGF-1 treatment (EE+IGF1 rats) did not further enhance the OD shift induced by MD in EE animals: the C/I VEP ratio measured in EE+IGF1 rats (; 1.08 ± 0.07) was completely comparable to that reported for EE animals (EE+MD), while it differed from that recorded in Nor+MD animals (One-way ANOVA = 46.48, , post hoc Holm Sidak method). The grey box denotes the C/I VEP ratio range in adult normal animals. *Statistical significance. NS: Not significant. Error bars indicate SEM.