(A–T’) Photographs of embryonic brains after in situ hybridization for POMCa, POMCb and AVT at 24, 36, and 84 hpf. The stages, the lateral or ventral orientations, and the probes are indicated. Blue squares indicate peptidergic clusters with higher numbers of neurons in SF. (E, F, M, N, U) Quantification and time-course of cell numbers in specific clusters. Mann-Whitney tests. (V) Anatomical interpretation of peptidergic patterns and time-course of appearance. POMCb (stars), POMCa (circles) and AVT (triangles) neurons are reported on schematic embryonic brains, in ventral or lateral views. A color code indicates higher numbers of neurons in CF (red) or in SF (blue), or equivalent numbers (grey). ac, anterior commissure; hyp, hypothalamus; NPO, neurosecretory preoptic nucleus; or, optic recess; orr, optic recess region; pit, pituitary; poc, post-optic commissure; tel, telencephalon; tub, tuberal hypothalamus; sv, saccus vasculosus. (W) Confocal pictures after double fluorescence in situ hybridization for POMCa/POMCb (left), POMCb/AVT (middle) and Hcrt/POMCb (right), showing colocalisation or lack of colocalisation of the indicated neuropeptides.