Figure 1

The paths of thalamocortical axons in wild-type and mutant embryos. Schematic representations of coronal sections of one side of the mouse brain at embryonic day 16.5 (E16.5). In wild-type embryos, the thalamocortical axons (TCA) extend ventrally from the dorsal thalamus (dTh), turn and cross the diencephalon-telencephalon boundary (DTB), enter the ventral telencephalon (vTel) and grow into the internal capsule (IC) where they separate into distinct fascicules. They then cross the cortico-striatal boundary (CSB) and turn dorsally into the cortex. In fuddle, magoo and wanderer mutants the axons are partially misrouted ventrally at the DTB. In sprawl and baffled mutants the axons are overfasciculated and are stalled at the CSB. In the bumpy mutant some axons aberrantly invade the marginal zone to innervate ectopic clusters of cells. HT, hypothalamus; vTh, ventral thalamus.