Fig. 7. The repulsive activity present in the basal telencephalon is maintained in Slit1;Slit2 double mutants. (A) Schematic of the experimental paradigm used to analyze the migration of MGE-derived cells in the presence or absence of cortex. (B) Migration of DiI-labeled cells from the MGE (asterisks) after 24 hours in culture. Labeled cells (arrowheads) approach the pallial/subpallial boundary (dotted white line) at the same time in the side of the slice without cortex (left) as in the side with cortex (right). (C) Schematic of the slice transplantation paradigm used to analyze the migration of MGE^GFP-derived cells in the absence of cortex in slices obtained from Slit1;Slit2 double mutants. (D) Migration of MGE^GFP-derived cells (asterisk) revealed after 48 hours in culture, labeled with GFP. Arrowheads point to cells in the pallial/subpallial boundary, dorsal to the striatum. (E) Schematic of the slice transplantation paradigm used to analyze the behavior of MGE^GFP-derived cells forced to migrate towards the preoptic area in slices obtained from Slit1;Slit2 double mutants. (F) Migration of MGE^GFP-derived cells (asterisk) after 48 hours in culture, labeled with GFP. Note that very few cells migrate into the MGE mantle (arrowhead) and none into the preoptic area. H, hippocampus; LGE, lateral ganglionic eminence; MGE, medial ganglionic eminence; NCx, neocortex; POa, preoptic area; Str, striatum. Scale bars: 300 µm.