Expression and level of Gad mRNA isoforms in the rostral and caudal forebrain in the wild-type and Dlx1/2 DKO demonstrated by digoxigenin in situ hybridization and quantitative real-time PCR. i, Gad65 isoform mRNA is expressed throughout the basal forebrain in a diffuse pattern in the wild-type (iA–iC, from rostral to caudal) compared with the Dlx1/2 knock-out forebrain (iD–iF, from rostral to caudal). Black arrows depicted ectopic accumulation of Gad65 mRNA in the basal ganglia. ii, Gad65 mRNA level was examined by real-time PCR in the basal ganglia and compared between wild-type (WT) and double-mutant (MT) littermates at E13.5. iii, Gad67 isoform mRNA is also expressed throughout the basal forebrain in a diffuse pattern in the wild-type (iiia–iiig, left, from rostral to caudal) and compared with Dlx1/2 DKO forebrain (iiia–iiig, right, from rostral to caudal). Black arrow depicted accumulation of Gad67 mRNA in the embryonic striatum at E16.5. iv, Gad67 mRNA levels were examined by quantitative real-time PCR in the basal ganglia and compared between wild-type and double mutant littermates at E13.5. The real-time PCR results show relative fold differences between wild-type and mutant littermates, and were normalized using the house keeping gene GAPDH as an internal control. Average ± SEM with associated p values. CGE, Caudal ganglionic eminence; LGE, lateral ganglionic eminence; MGE, medial ganglionic eminence; ST, striatum; VTH, ventral thalamus; AH, anterior hypothalamic nucleus; DMH, dorsal medial nucleus; OT, olfactory tract; SE, septum; VP, ventral pallidum; PO, preoptic area; VLGN, ventral lateral geniculate nucleus; ZI, zona incerta nucleus; RN, red nucleus. Scale bars: iA–iF, iiia–iiid, 200 μm; iiie–iiig, 400 μm .