Figure 4.

The qualitative feeding assay is sensitive. (A-D′) Dorsal views with anterior to the left of the hindbrain of 7 dpf Tg(isl1:gfp) larvae from the indicated treatments. In control larvae that were either not manipulated in any way (A, A′) or embedded in agarose to mimic laser ablation conditions (B, B′), all branchiomotor neurons, including the trigeminal motor neurons (nV, arrowheads), were unaffected. (C, C′) In this embedded larva, the nV motor neurons were ablated by laser irradiation at 6 dpf and examined 1 day later. Very few nV neurons (arrowheads) remain, reflecting the loss of most of these neurons due to ablation. (D, D′) The sham-ablated larva was embedded and laser-irradiated bilaterally in a region immediately rostral to the nV neurons, for the same duration as nV-ablated larvae. The nV neurons were unaffected in these larvae. The cranial motor neurons in the midbrain (asterisk) are not affected under these conditions. (E) Distribution of feeding scores for larvae undergoing different treatments. Data pooled from 3-6 experiments (number of larvae in parenthesis). Larvae with ablated trigeminal motor (nV) neurons ate significantly less than their control non-ablated siblings. Asterisk, Chi-square test with Bonferroni correction indicating significance at p < 0.004; NS=not significant.