Figure 4. Copyright: Reprinted with permission from Elsevier from [doi:10.1016/S0012-1606(03)00295-1] Dev Biol, 261: 82-98, Bhasin N; Maynard TM; Gallagher PA; LaMantia AS, "Mesenchymal/epithelial regulation of retinoic acid signaling in the olfactory placode." Copyright 2003 [PMID:12941622]