Figure 1: Embryonic eye removal triggers experience-independent cross-modal changes in S1 somatosensory cortex.

(a) Brn3b^Cre/+;R26^tdTomato mouse shows the absence of retinal axons in the dLGN at E14.5 and their presence at E15.5. (b) Labelling of principal sensory cortical areas at P8 in a control TCA-GFP transgenic mouse or in a TCA-GFP mouse in which bilateral enucleation has been performed embryonically. (c) Quantification of the areas of S1, V1 and A1 shown in b (***P<0.001 for S1 and V1; not significant (ns): P=0.76 for A1; Two-tailed Student’s t-test). (d) vGlut2-immunostaining in the posteromedial barrel subfield (PMBSF) of S1 in control (n=10) and embBE (n=14) mice at P4. (e) Experimental design and quantification of the total PMBSF area shown in d (*P=0.03; Two-tailed Student’s t-test). The expansion of the PMBSF in the embBE was proportional along the medio-lateral axis (630.30±39.04 pixels in control and 670.71±38.79 pixels in embBE) and the anterio-posterior axis (326.60±18.66 in control and 337.93±26.35 in embBE mice. (f) Plot of the area of each individual barrel (left) and quantification of the mean individual barrel area (right) in control and embBE brains at P4 (*P=0.011; Two-tailed Student’s t-test). Inset describes the barrels that are significantly expanded in the embBE mice compared with controls. (g) Design of the experiment and quantification of the individual barrel area of control (n=13), control dewhiskered (n=16), embBE (n =12) and embBE dewhiskered (n=13) mice at P4 (*P<0.05; ns, not significant; Two-way ANOVA test with Tukey’s post hoc analysis). Interaction between dewhiskering and embBE was not significant (P=0.77). (h) vGlut2-immunostaining in the VPM nucleus of the thalamus in control and embBE mice at P4, quantification of the total barreloid area (control 100±6.23%, n=4; embBE: 102.1±7.11%, n=4; P>0.99; Mann–Whitney U-test). Graphs represent mean±s.e.m. Scale bars, 1 mm in b and 300 μm in a,d,h.