Fig. 1

spon1b:GFP expression in cell populations from 24 to 48 hpf in telencephalic and diencephalic regions. a Maximum intensity projection (MIP) of a 10 µm optical slice of GFP fluorescence (green) overlaid with a transmitted light image (gray) for anatomical reference. This MIP at the dorsal telencephalon shows population i. Olfactory placodes are circled for anatomical reference. Telencephalic ventricle is shown with a continuous white line. b MIP obtained from a 30 µm thick slice at the developing dorsal and ventral telencephalon and diencephalon, showing populations II, III and IV. Population II corresponds to the pituitary anlage (dashed line), identified adjacent to the ventral diencephalon using transmitted light images as anatomical reference. c Detail of the pituitary anlage enclosed in red in (b). Arrows outline the border of the pituitary anlage. d Cells in population III show a characteristic morphology along the neuroepithelium. The MIP of a 12 µm thick slice of cells in population III of a different individual shows prolongations along the developing neuroepithelium at 27 hpf (red arrows), but at the same approximate location as (b). White asterisks indicate eye position. e MIP obtained from a 60 µm slice showing the tips of axonal processes in the midline and commissure at the telencephalon from populations I–I*. f Detail of axonal processes and commissure (white arrow) enclosed in (e). g MIP obtained from a 75 µm slice at the dorsal diencephalon and tectum showing individual cells in newly identified population V (white arrowheads), and two bilateral clusters as VI (dashed circles). h MIP obtained from a 50 µm slice showing population I and IV (white arrowheads). i MIP obtained from a 90 µm slice showing populations II-IV. White arrowheads show cells from the olfactory system. Images from a–i are frontal views. Schematic drawings of zebrafish embryos at the right show the approximate position of planes in a–i