Fig. 1

Post-optic commissure formation in zebrafish embryos. The post-optic commissure (POC) is formed by midline crossing axons (AT) in concert with a structure of glial cells called the glial bridge (Gfap). A) Frontal MIP of the zebrafish forebrain at 20 hpf labeled with anti-acetylated tubulin (AT) (green) and anti-Gfap (red). Gfap signal is distributed across the whole forebrain with the glial bridge beginning to condense in both the telencephalon (top half) and diencephalon (bottom). The first pioneering axons are visible in the diencephalon, where they will construct POC. B) Frontal MIP of the zebrafish forebrain at 24.5 hpf labeled with AT and Gfap. Axons (green) are observed pioneering the diencephalic midline, forming the POC, in concert with the glial bridge which has condensed around the forming commissure. C) Frontal MIP of the zebrafish forebrain at 36 hpf labeled with AT and Gfap. Both the diencephalic POC and telencephalic anterior commissure have been successfully constructed and positioned at the midline in concert with their respective glial bridges. D) Model of the commissure (green) and glial bridge (blue) positioning in the zebrafish forebrain with respect to the eye and dorsal and ventral clusters.