Fig. 6. The basal telencephalon and hypothalamus contain a non-permissive activity for cortical axons. (A,C) Experimental paradigm for cortical-basal telencephalic (A) and cortical-hypothalamic (C) co-cultures in three-dimensional collagen matrices. Green slices and explants are derived from E13.5 GFP transgenic embryos, whereas gray slices and explants are derived from wild-type littermate embryos. (B,D) Explants after 72 hours in culture showing immunohistochemistry for GFP. The broken lines indicate the location of the non-GFP expressing explants. BT, basal telencephalon; Hyp, hypothalamus; NCx, neocortex.