Figure 1.

The corpus callosum in Ryk^−/− embryos form axon bundles on the contralateral side of the midline. Coronal sections of E18 forebrain from wild-type (A, C) and Ryk^−/− (B, D) embryos stained for Nissl substance (A, B) or with hematoxylin and eosin (C, D). In wild-type cortex, callosal axons cross the midline in a tightly fasciculated tract (A, C, arrows). In Ryk^−/− cortex (B, D), callosal axons cross the midline and form axon bundles (arrows) on the contralateral side of the midline. The intermediate zone in the Ryk^−/− cortex (arrowheads) contains fewer axons than that in wild-type brain. Scale bar, 200 μm.