At top, we illustrate the gene network that establishes pallial/subpallial proportions (see also Ulloa and Marti12). Arrows indicate positive signal; T bars indicate negative interactions. For all panels, mbunas are on the left, and non-mbunas are on the right. All schematics are lateral, midline representations. Neu, neurula; 5s, 5 somites; st11, stage 11 (6–12 somites); st12, stage 12 (13–20 somites). (a) Greater DV progression of shh expression in mbuna versus greater AP deployment of Wnt in non-mbuna. (b) Increased shh in mbuna leads to earlier induction of foxg1, by 4–5s. gli3 is present in the presumptive telencephalon of mbuna and non-mbuna, counteracted by foxg1 in mbuna only. (c) As wnt8b enters the telencephalon, mbuna foxg1 has been established for some time. Non-mbuna foxg1 is first expressed in the telencephalon slightly after wnt8b. (d) Early elaboration of foxg1 in mbuna and gli3/wnt8b in non-mbuna establishes contrasting readouts of ventralizing versus dorsalizing signals, at stage 12.