||FIG. 1. Bright field (A) and pseudo-darktield (B-D) micrographs of the in situ hybridization signal
in Xenopus brain. (A) The signal appears as clusters of dark silver grains over individual cells (solid
arrows) with a high signal-to-noise ratio (compare labeled cells with unlabeled cells, open arrows).
Inset is fourfold magnification of that indicated in the box and illustrates cellular resolution of the
signal. (B-D) The autoradiographic signal in these pseudo-da&field micrographs appears as white
clusters of grains over individual cells that exhibit a distinct topography. The background appears
higher than actual due to tissue reflectance (compare A with B-D). Lettering refers to adjacent labeled
cells. Al, amygdala, pars lateralis; Am, amygdala, pars medialis; NAS, nucleus accumbens septi;
NEP, nucleus entopeduncularis; NMS, nucleus medialis septi; NPO, nucleus preopticus; STv, striaturn,
pars ventralis. 67x.