Fig. 3

Trh neurons form a transient circuit on the primary head sinus. (A) Immunolabeling of the Trh circuit (green) in prehatching 2-dpf embryos (top) and posthatching 3.5-dpf embryos (bottom). The red arrowheads mark the location of hindbrain Trh projections in prehatching embryos. Illustrations on the right show schematic representation of the Trh circuit before and after hatching. E, eye; HB hindbrain; OV, otic vesicle; P pituitary. (B) Lateral view of a 2-dpf prehatching embryo with labeled vasculature (green) and Trh (magenta). The bottom image is an enlargement of the boxed area in the top picture. The images were generated by surface rendering of a confocal image using Imaris software. The illustration on the top depicts the vasculature structure and names of the main blood vessels. (C) Ventral views of a prehatching embryo. Details are the same as in (B), except that the top image is a raw confocal image. DC, duct of Cuvier; PHBC, primary hindbrain channel; PHS, primary head sinus; PMBC, primary midbrain channel.