Figure 5.

Endogenous neurogenic potential of the PWM microenvironment. a–c illustrates the positions acquired by P7 rat β-actin-GFP-positive interneurons transplanted to P1 wild-type rat recipients as single-cell suspensions (a), as reaggregated cells (b), or as solid pieces of PWM (c) analyzed 1 month after graft. The different procedures yielded similar phenotypic repertoires and laminar positions (one-way ANOVA with Bonferroni's multiple comparison test; p = 0.29). d–f shows examples of transplanted GFP-positive interneurons (green) obtained from dissociated (d), reaggregated (e), or solid (f) grafts. g–i, Preferential localization of dissociated P1 (g) or P7 (h) cells transplanted to adult hosts. Donors of both ages yielded stellate cells located close to the molecular layer (ML) surface (i). j–n, Solid grafts from P1 or P7 β-actin-GFP-positive rat donors transplanted to adult cerebella give rise to numerous interneurons distributed throughout the host cortex, and white matter (WM) (i, j). Even in ectopic positions, the transplanted cells produced phenotypic repertoires consistent with their donor age (k). For instance, P1 cells in the host white matter generated both neurogranin-positive granular layer (GL) interneurons (red in l) and parvalbumin-positive ML interneurons (PV, red in m), whereas P7 donors exclusively produced the latter phenotype (n). Sol, Solid graft; Diss, dissociated cell graft; Ad, adult; PCL, Purkinje cell layer. Scale bars: (d, f, j), 100 μm; (e, g, h), 50 μm; (n), 20 μm; (l, m), 10 μm.