Fig. 5: The transplanted cerebral organoids successfully extended long-distance subcortical axonal projections to basal brain regions.

a Slide scanner images of GFP-stained sagittal brain sections obtained from a grafted mouse brain at 3 MPT showing long projections (n = 3 mice). b–e High-magnification views of the sampled regions are shown in (a). DP dorsal peduncular cortex, DTT dorsal tenia tecta, VP ventral pallidum, LH lateral hypothalamus. f Illustration of the timeline of cell transplantation, retrograde labeling, and analysis. g The retrograde tracer CTB 555 reached the grafted cells and was coexpressed with hN (upper left). A representative image of immunostaining for the cortical projection neuron markers TBR1 (upper right), FOXP2 (bottom left), and CTIP2 (bottom right), each of which was coexpressed with CTB555. Scale bar: 100 µm. h Quantification of CTIP2⁺, TBR1⁺, FOXP2⁺, DCX⁺, NESTIN⁺, and SOX2⁺ cell populations in the CTB 555⁺/hN⁺ graft area (n = 3 mice, mean ± SEM). Scale bars: 100 µm.