Fig. 4. Retinal ganglion cell axon pathway and projections are altered in Vax2 mutant mice. The ventral retina (C,D) or the right optic nerve head (A,B; E,H) of new-born wild-type (WT) or Vax2 mutant mice were filled with DiI to label the retinal ganglion cell axon trajectory. (A-D) Ventral views of the brain at the chiasm region (dotted lines indicate the midline). (E,H) Coronal sections through the contralateral (E,F) and ipsilateral superior colliculus (G,H). All sections are oriented rostral (R) towards the top and lateral (L) towards the right, as indicated in E. Note how retinal ganglion cell axons normally projecting in the ipsilateral optic tract (arrows in A,C) are totally absent in the mutant mice (B,D). Furthermore, note how, in mutant mice, projections to ipsilateral superior colliculus are absent (compare G with H), while those to the contralateral side terminate predominantly in the lateral region (compare E with F), where normally the majority of axons arising from the dorsal retina project.
