Fig. 2
Activity in a subset of cells in the pretectal area in the presence of prey. (a) UAS:EGFP reporter gene expression in the pretectal area (PT, encircled in dotted lines) in gSAzGFFM119B Gal4 larva at 5?d.p.f. Scale bar, 50??m. (b) Pretectal activation in response to prey at 4?d.p.f. GCaMP6s fluorescence images. Scale bar, 500??m. (c) GCaMP6s fluorescence intensity in the pretectal areas shown in b. Asterisks: missed data points due to large movements of the larva. (d) Averaged activity of the bilateral pretectal areas in the presence of prey in a 6?d.p.f. larva embedded in agarose. The trajectories of a single paramecium over 107?s with colour-coded changes in the intensity of GCaMP6s fluorescence in the pretectal areas. Scale bar, 1?mm. (e) Confocal images showing pretectal activation in response to a moving spot. Scale bar, 50??m. (f) GCaMP6s fluorescence intensity obtained from the time-lapse images in e. A moving spot of 2.4° in diameter was presented to a larva at a speed of 100?deg?s?1 from 0.3 to 3.4?s. (g,h) Size-tuning and speed?tuning curve, respectively (n=6 larvae at 4?d.p.f.; Meanąs.e.m.). Maximal responses to a moving spot. The x-axis is logarithmically scaled. (i) Relative positions of the paramecium at the onset of prey capture in free-swimming larvae at 5?d.p.f. (n=110 successfully completed prey capture events by 6 larvae). Scale bar, 1?mm. j, Probability density of the paramecium positions shown in i. Colour bar:0 (blue) and 9 × 10?5 (red). Scale bar, 1?mm. (k,l) Histograms of the apparent sizes and speeds, respectively, of the prey at the onset of prey capture from the data shown in i. (m) Paramecium consumption in the UAS:EGFP; gSAzGFFM119B larvae that were subjected to bilateral pretectal ablation (n=10, thick magenta line) or unilateral (n=10, thin light-magenta line), UAS:EGFP; gSAzGFFM119B larvae subjected to bilateral olfactory bulb ablation (n=11, green) and UAS:EGFP; gSAzGFFM119B larvae (no laser irradiation, n=8, black). Solid lines:mean. Dotted lines: s.d. Asterisks: significant differences between each of pretectum ablation groups and each of control groups at 10?min (Tukey?s HSD test, P=0.0016 for bilateral pretectum ablation and olfactory bulb ablation). |