The top panel shows the time-course of parapineal development in Tg(foxD3:GFP);(flh:eGFP) fish. The time-points selected for parapineal ablations are shown in orange. (A–O) Dorsal views of the epithalami of wild-type and parapineal-ablated larvae at 4 dpf showing expression of (foxD3:GFP)zf104 and (flh:eGFP)U711transgenes (grey) in the pineal complex. Habenular mRNA expression of kctd12.1, nrp1a and VAChTb is shown in magenta. Parapineal ablations were carried out at time-points indicated on the left. Scale bar 25 µm. (P–T) Dorsal (left images) and lateral (right images) views of the interpeduncular nucleus labelled by anterograde tracing of the axons from the left dorsal habenula (lHb, green) and right dorsal habenula (rHb, magenta) at 4 dpf. Parapineal ablations were carried out at time-points indicated on the left. dIPN – dorsal interpeduncular nucleus. Scale bar 25 µm.