Figure 2.
Prey capture requires the tectum and is vision dependent. A, Laser ablation of the tectum in GFP-expressing larvae. The left panel is a projection of a confocal image stack showing GFP expression in RGCs terminating at the tectum in Brn3c:mGFP transgenic larvae (20 images taken at 2 μm intervals). The optic chiasm and GFP-expressing hair cells are also visible. The right panels show an enlargement of the boxed section containing the tectum on both sides. These are single images acquired under epifluorescence, showing the same section before (top) and after (bottom) laser ablation of the left tectum. After 3 min of visually guided lasing, GFP expression is no longer visible in the left tectum but is unchanged in the right tectum. B, The effects of tectum ablation and ambient lighting on prey capture performance. Larvae tested in the dark (GFP+ Dark) captured significantly fewer paramecia than untreated controls (GFP+ Light). Bilateral tectum ablation (Bilat Tect Abl) impaired performance to a similar degree as testing in darkness, whereas unilateral tectum ablation (Unilat Tect Abl) had an effect intermediate between bilateral ablation and control conditions. There was no significant difference between right- and left-tectum-ablated groups, shown for the 5 h sampling point only (R.Tec and L.Tec, respectively). C, Prey capture performance of blind lakritz mutants (lak) and wild-type siblings tested in normal lighting or in darkness. The poor performance of blind mutants and larvae tested in darkness relative to controls supports the vision dependence of prey capture.
