Extended Data Figure 10. Characterization of Dlxi1/2b::eGFP⁺ cells after migration.

(a) Representative images of 3D–reconstructed Dlxi1/2b::eGFP⁺ cell morphologies before and after migration from hSS into hCS. (b) Quantification of dendritic branching of Dlxi1/2b::eGFP⁺ cells in hSS (n= 58 cells) and in hCS (n= 55 cells) of fused hSS-hCS (two-way ANOVA; interaction F(2, 129)= 11.29, P< 0.001; Bonferroni post-hoc *P< 0.05, ***P< 0.001). (c) Representative examples of action potentials (slice recordings) in Dlxi1/2b::eGFP⁺ cells in unfused hSS, in hSS of fused hSS-hCS and in hCS after migration in fused hSS-hCS. (d) AT showing expression of the GABAergic synapse marker GPHN (green) colocalized with SYN1 (red) in hCS of fused hSS-hCS but not in unfused hCS; the glutamatergic marker PSD95 (cyan) colocalized with SYN1 is found in both fused and unfused hCS (equal volumes 1.2 μm deep). (e) AT of a Dlxi1/2b::eGFP⁺ synapse illustrating the colocalization with SYN1 (red), GPHN (cyan), and VGAT (white); 5 consecutive 70 nm sections (3 × 3 μm). (f) Representative examples of whole-cell voltage clamp recordings of IPSCs and EPSCs from Dlxi1/2b::eGFP⁺ cells in unfused hSS, in fused hCS-hSS, or after migration in hCS (g) Representative examples of whole-cell voltage clamp recordings of IPSCs and EPSCs in cells recorded from unfused hCS cells and fused hCS cells. (h) Electrical stimulation and patch clamp recording in fused hSS-hCS showing evoked EPSCs and IPSCs before (black) and after exposure to 10 μM gabazine (red). (i) Average peri-stimulus synaptic events (IPSCs and EPSCs) in Dlxi1/2::eGFP⁺ cells recorded in the hCS side of fused hSS-hCS before and after electrical stimulation (paired t-test, *P< 0.05). Data are mean ±  s.e.m.