Fig. 1. Marker gene characterisation of "late" lithium phenotypes by in situ hybridisation of (A-C) tailbud stage and (D-H) 24 hpf (wild type, left) and lithium- treated (Li+, right) embryos (A,C,D,F,G,H, lateral view; B,E dorsal view; anterior to the left). (A,B) Anteriorly shifted wnt1 covers the anterior neural plate (Li+). (C) Shh is diminished in the anterior midline (Li+). (D,F) The mild phenotype is characterised by the loss of brain anterior to D2/3 diencephalic boundary as revealed by (D) pax6 and (F) otx2. (E,G) The severe phenotype is characterised by the loss of brain anterior to the MHB as revealed by (E) pax6 and (G) wnt1. MHB was absent in the most severe cases (*). (H) The hindbrain was unaffected by the treatment as shown by krox20 expression.