Extended Data Fig. 4|. Thalamic explant monocultures and co-cultures with striatal and hypothalamic explants.

a, Axon outgrowth from monoculture of thalamic explants (Th) from E14.5 offspring of SPF, ABX, GF and Sp dams. Scale=250 μm. In Th monocultures: b, axon number, and c, axon length (One-way ANOVA+Tukey’s, n=26, 20, 21, 10 explants). d, Axon outgrowth from i) SPF Th+SPF hypothalamic explant (Hy), ii) ABX Th+ABX Hy, iii) SPF Th+ABX Hy, iv) ABX Th+SPF Hy. Scale=250 μm. Proximal to Hy: e, axon number /200 μm² surface area, normalized to Th monoculture, and f, axon length, normalized to Th monoculture. (One-way ANOVA+Tukey’s, n=14, 20, 9, 10 explants). g, Axon outgrowth from GF Th+GF St. Scale bar=250 μm. Proximal to St: h, axon number/200 μm² surface area, normalized to Th monoculture, and i, axon length, normalized to Th monoculture. (One-way ANOVA+Tukey’s, n=16 GF explants). j, Axon outgrowth from GF Th+GF Hy. Scale bar=250 μm. Proximal to Hy: k, axon number/200 μm² surface area, normalized to Th monoculture, and l, axon length, normalized to Th monoculture. (One-way ANOVA+Tukey’s, n=14 GF explants). m, Axon outgrowth from i) SPF Th+SPF St, ii) ABX Th+ABX St, iii) Sp Th+Sp St, iv) Sp Th+ABX St. Scale=250 μm. Proximal to St: n, axon number/200 μm² surface area, normalized to Th monoculture, and o, axon length, normalized to Th monoculture. (One-way ANOVA+Tukey’s, n=14, 20, 14, 6 explants). p, Axon outgrowth from i) SPF Th+SPF Hy, ii) ABX Th+ABX Hy, iii) Sp Th+Sp Hy, iv) Sp Th+ABX Hy. Arrows=sparse short axons. Scale=250 μm. Proximal to Hy: q, axon number/200 μm perimeter, normalized to Th monoculture, and r, axon length, normalized to Th monoculture. (One-way ANOVA+Tukey’s, n=14, 20, 14, 6 explants). SPF and ABX data in g-i and m-o are in Figure 1l, 1m. Mean±SEM. *p<0.05, **p<0.01, ***p<0.001, ****p<0.0001, n.s.=not statistically significant.