Fig. 3

a, Timelines of manipulations for late OPC ablations. b, Examples showing unilateral laser ablation of OPCs in the tectum. Scale bar, 20 µm. c, Reconstructions of time-projected RGC arbors highlighting stable, eliminated and added processes. Quantifications show diminished developmental reduction of RGC arbors between 7 d.p.f. and 10 d.p.f in OPC-ablated animals (left graph), mediated by decreased branch eliminations (middle) and enhanced additions (right) (left: mean 13.6 ± 12.1 s.d. in control versus 1.7 ± 9.2 in OPC laser ablation; middle: 37.9 ± 6.7 versus 29.9 ± 6.6; right: 19.5 ± 5.2 versus 28.8 ± 10.2; n = 17/14 cells in 11/9 animals from four experiments, unpaired two-tailed t-test, left: t = 3.022, d.f. = 29; middle: t = 3.372, d.f. = 29; right: t = 3.089, d.f. = 18.44). d, e, Impaired paramecium capture rates upon tectal OPC laser ablation (d) and OPC NTR ablation (e); (d: mean 27.6 ± 4.9 s.e.m. in sham control versus 29.7 ± 6.3 in telencephalic OPC ablation versus 49.2 ± 4.2 in tectal OPC ablation at 2-h time point, n = 11/10/23 animals from four experiments, two-way ANOVA, F_4,123 = 3.369); (e: mean 35.2 ± 7.3 s.e.m. in MTZ control versus 70.2 ± 5.1 in OPC NTR ablation at 2-h time point, n = 18 animals per group from four experiments, two-way ANOVA, F_2,102 = 6.759). f, Experimental setup of OMR elicited by moving gratings of different spatial widths and example trace of tail bout recording. g, First bout latencies in OMR assays. Violin plots show distribution of individual data points at 10 mm and 3.3 mm spatial frequency (10 mm: median 1.2 ± 1.6/0.7 IQR in control versus 1.5 ± 2.9/1.0 in OPC NTR ablation; 3.3 mm: median 1.6 ± 3.9/0.9 in control versus 3.4 ± 9.9/1.1 in OPC NTR ablation; n = 35/37 animals from six experiments, two-way ANOVA, F_6,490 = 1.853). h, Enhanced possibility of failure to initiate swimming in response to narrow moving gratings upon OPC NTR ablation (one-tailed Fisher’s exact test). i, Top, visual stimulation protocol for analyzing responses of tectal neurons. Bottom, example anatomies obtained from calcium imaging in two different planes. Dashed lines indicate optic tectum. j, Visual responses from an example neuron. Each plot reports individual (black) and average (red) responses; plot position indicates position of the stimulus (top is frontal). Polar histogram represents the reliability score for this neuron to each stimulus position. k, Decreased number of reliably responsive neurons in OPC-ablated animals (median 457 ± 351/633 IQR in control versus 307 ± 123/386 in OPC NTR ablation, two-tailed Mann–Whitney U-test, U = 2.6465, n = 12/11 animals from three experiments). l, Decreased response amplitudes in OPC-ablated animals (median 0.700 ± 0.658/0.791 IQR in control versus 0.624 ± 0.536/0.672 in OPC NTR ablation, two-tailed Mann–Whitney U-test, U = 2.4618, n = 12/11 animals from three experiments).