PAX6 and Bartsocas-Papas syndrome 1: Ngn2 (i) promotes the expression of insulinoma-associated 1 (Insm1), a zinc-finger transcriptional regulator of the SNAG family that has been implicated in the generation of BPs [73,74]; (ii) promotes the expression of Scratch 1 and Scratch 2, two other members of the SNAG family that are implicated in triggering the onset of migration of BPs and newly-generated neurons [75]; (iii) directly activates the expression of Tbr2 [51,60,72,76]; and (iv) represses Pax6 expression [58,60,72].