Fig. 5

Analysis of local and long-range primary afferents to human striatal grafts at 6MPT. A and A′ Representative images of both SE (left) and EE (right) striatal grafts in which mCherry-labeled cells are visible upon mRV transduction. B and B′ High magnification confocal pictures of SE and EE transplants displaying viral-labeled mCherry-positive starter (GFP⁺) and traced (GFP⁻) cells. C Quantification of starter and traced cells per slice in SE and EE conditions (one way ANOVA, p > 0.05 ns. N = 4 SE; 6 EE). D and E Expression of striatal (CTIP2, DARPP32) or interneuron (CR, CB) markers in starter cells (D; two-way ANOVA, Group, p > 0.05 ns, markers, p < 0.01; N = 4 SE, 6 EE) and in mCherry⁺ input neurons (E; two-way ANOVA, Group, p > 0.05 ns, markers, p < 0.001; N = 4 SE, 6 EE), both from graft and host cells, in SE and EE conditions. F Quantification of host connections to starter neurons at 2 and 6MPT, in SE or EE housing (one way ANOVA, p < 0.05; Bonferroni post hoc test, 2MPT vs. 6MPT EE, p < 0.05; 6MPT SE vs. 6MPT EE, p < 0.05. N = 4 2MPT; 4 6MPT SE; 6 6MPT). G Number of grafted animals showing extrastriatal afferents and number of extrastriatal first afferents found in different brain regions in SE and EE conditions. H–L Schematic illustration of the antero-posterior distribution of extrastriatal host mCherry-positive first-order input neurons in SE and EE slices. Pictures display representative examples of extrastriatal rat neurons connecting to human grafted neurons and localized in diverse brain areas, such as the frontal cortex (H, I); thalamus (J), hypothalamus (K), substantia nigra and amygdala (L). Data are represented as mean ± SEM. Scale bars: 1 mm (A and tile-scans in H–K); 50 μm (B); 100 μm (high magnification in H–K)