Figure 4

Fates of Fgf8 ⁺ and Fgf17 ⁺ RPC cells in adult forebrains. Anti-βgal IHC on coronal sections through (A) Fgf8 ^CreER/+; TauR, (B) Fgf17 ^CreER/+; TauR, and (C) Fgf17 ^CreER/-; TauR forebrains at P40 (Tm E8.5). Abbreviations (see also Figure 2 legend): B, nucleus basalis of Meynert; POA, preoptic area; Fr, frontal cortex; Pir, piriform cortex; RS, retrosplenial cortex; OT, olfactory tubercle. Septum: Both Fgf8 ⁺ and Fgf17 ⁺ progenitors give rise to cells in the lateral septum (LS), medial septum (MS), septofimbrial and septohypothalamic nuclei, triangular septal nucleus, and indusium griseum. The MS, which receives substantial contribution from the MGE [37], contained fewer labeled cells than other septal regions. Cortex: Fgf8 ⁺ lineage cells were observed in the PFC and in most neocortical regions but were most concentrated in rostrodorsal areas (medial and dorsal frontal cortex, PrL, IL, Cg, M, RS). In contrast, Fgf17 ⁺ lineage cells only populated the medial PFC and the Cg, M, and dorsal S areas of the neocortex. Basal ganglia: The Fgf8 ⁺ lineage, but not the Fgf17 ⁺ lineage, makes prominent contributions to the striatum, ventral pallidum, accumbens, and globus pallidus. We observed left/right asymmetries in Fgf8 ⁺ and Fgf17 ⁺ fate maps that were particularly striking in the neocortex, shown in Additional file 3: Figure S3. See also Figure 3.