Figure 3: Developmental increase in ultraviolet:blue cone synapse ratio occurs by selective addition of ultraviolet cone connections.

(a) Plots across ages of the mean ratio of the ultraviolet:blue cones available (circles) as well as the adjusted mean ratio of ultraviolet:blue cones that are contacted by H3 HCs (triangles). Contacted (n=6 for 3.5 d.p.f., n=12 for 5.5 d.p.f., n=8 for 10 d.p.f.); available (n=4 for all ages). (b) Mean H3 HC dendritic field sizes at different ages. (c) (Upper panel) Connectivity maps of representative H3 HCs at different ages. A circle (yellow) with an area equivalent to the average 3.5 d.p.f. H3 HC dendritic field size was centred on the centre of mass of the dendritic field. (Lower panel) The mean numbers of ultraviolet and blue cone synapses within (In) or outside (Out) the yellow-filled circle were plotted for cells reconstructed at different ages. In general, synapses added outside the circle largely represent addition of synapses to the dendrites that grew after 3.5 d.p.f. In all panels, ultraviolet and blue cone synapse numbers obtained from FP expression in transgenic fish were adjusted according to the values of % transgenic expression per opsin expression from Supplementary Fig. 2. All error bars are s.e.m. P-values from Wilcoxon–Mann–Whitney rank sum test. n=6 for 3.5 d.p.f., n=9 for 5.5 d.p.f., n=8 for 10 d.p.f. in (b,c).