Figure 1

Factors that pattern the mammalian cortex. (a) Dorsal view of the mouse cerebral cortex at day E13.5 with the rostro-caudal gradients of the transcription factors Pax6 and Emx2 superimposed (see [9]). (b) The early cortex areal identity along the rostro-caudal axis can be imparted by the interpretation of different relative concentrations of transcription factors such as Pax6 and Emx2 at different positions along the axis. (c) Signals that pattern the cortex. Fibroblast growth factors (FGFs; purple) are expressed first in the anterior neural ridge and then in the anteromedial telencephalon, and may participate in early cortical patterning by signaling in the direction of the arrows (reviewed in [12]). (d) Sansom et al. [5] interrogated the genetic identity of the neocortex by performing a microarray study on discrete rostral and caudal portions of the neocortex at E11 and E13 developmental stages.