Fig. 6. Predicted shifts in the cortex of PAX77 mice. (A) Pax6 levels are about three times higher in the anterior cortex than in the posterior cortex. In PAX77 mice, Pax6 expression is still graded, but is increased by 1.5- to 3-fold (shown here as an average of approximately 2-fold). Thus, in PAX77 embryos, cells in posterior regions of the cortex express levels of Pax6 that are normally found in anterior regions. (B-D) Dorsal views of mouse neocortex. (B) In the wild-type, Pax6 is expressed in a rostro-lateral^high to caudo-medial^low gradient, while (C) Emx2 is expressed in an opposite gradient. We predicted that the overexpression of Pax6 would result in a downregulation of Emx2 expression and (D) in a caudal shift of rostral areas at the expense of caudal areas. M, motor area; S, somatosensory area; V, visual area.