Neuronal diversity in the mammalian forebrain is generated in part by cells following different tangential migration pathways to their final destinations during telencephalon development. These pathways and the molecular mechanisms underlying them are poorly understood. Now, Tripodi and colleagues describe,on p. 6119, a new dorsal-to-ventral migratory pathway in developing mouse brain that runs from the basal telencephalon to the pre-optic area and anterior hypothalamus. The researchers report that the nuclear receptors COUP-TFI and COUP-TFII are differentially expressed in cells that follow distinct migratory routes in the developing telencephalon. Ectopic expression of COUP-TFs increases the rate of cell migration and cell dispersal, and the exact pathway that migrating cells follow in transplantation experiments depends on which COUP-TF they express. Thus, the researchers speculate, COUP-TFs could regulate the guidance cues that direct tangential cell migrations in the developing telencephalon.