Figure 7.

Impaired trigeminothalamic pathway in slit knockout mice at E15; DiI crystal was placed in the PrV to trace trigeminothalamic pathway. Axons of PrV neurons crossed the midline and took a sharp rostral turn towards contralateral thalamus at E15 in control embryos (A). Different pathfinding errors including stalling of post-crossing axons, partial crossing and running of trigeminothalamic projection within the midline were observed in slit1 knock out embryos (B, C, D). Few stalling of axons and running of trigeminothalamic projection at close proximity to the midline were observed in slit2 knockout embryo (E). Marked stalling of post-crossed axons was found in slit3 knockout embryos (F). In slit1 and slit2 double knockout embryos, crossed axons reentered the midline (arrows, G, H). H is a higher power view of the boxed region in G. Minor path finding errors with few axon stalling was observed in slit2 and slit3 double knockout embryos (I). Scale bars are 100µm and asterisks mark the midline. Scale bar in A = 50µm.