Fig. 4. Normal pathfinding of layer 6 cortical projections in Nkx2-1 mutants. Coronal sections through the telencephalon of E18.5 wild-type (A,B) or Nkx2-1 mutant mice (C,D) showing the path followed by corticothalamic connections (A,C; white arrowheads) and retrogradely labeled cortical cells (B,D; open arrowheads) after DiI crystal placements in the dorsal thalamus. (C) The arrow points to the poor-cell region containing the abnormal tract formed by layer 5 cortical axons (not labeled in this experiment) present in Nkx2-1 mutants (see Fig. 3F). c, cortical plate; cp, cerebral peduncle; GP, globus pallidus; Str, striatum; Str*, mutant striatum; V, layer 5 cortical neurons; VI, layer 6 cortical neurons. Scale bar: 200 µm in A,C; 100 µm in B,D.
