Fig. 1. Key gene expression and migration patterns in telencephalic development. (A) The key morphogens, (B) the patterning transcription factors and (C) the main pathways of ventrodorsal cell migration in a frontal section of a DAPI-labelled telencephalon of the developing mouse telencephalon at embryonic day 13. Many signalling and migrational pathways, as well as transcription factors, have been omitted, as we have illustrated here just the morphogens, transcription factors and migrational pathways discussed in the text. Dark green, late migrating interneurons; light green, early migrating interneurons; red, late generated oligodendrocytes; yellow, early generated oligodendrocytes. c. hem, cortical hem; ctx, cerebral cortex adjacent to the choroid plexus (yellow); lge, lateral ganglionic eminence; mge, medial ganglionic eminence.