TBR1 is necessary for ASD gene expression in specific cortical lamina. Radioactive in situ hybridization (RISH) of high-confidence genes at E15.5 (A) and P0 (B) in Tbr1+/+ and Tbr1−/− cortices reveal expression differences. RISH expression (lines in shades of red) corresponds to normalized grain counts (see Methods), and significance was determined using the two-sided t-test (n = 3–6 sections encompassing three samples per genotype) (see Methods). E15.5 cortical plate (red), P0 upper layers (brown), and P0 deep layers (pink). Upper layers correspond to layers 2–5 and deep layers correspond to layer 6 (see Methods). Error bars represent SD. (*) P-value < 0.05; (**) P-value < 0.01; (***) P-value < 0.001.
