Digital images show immunoreactive GAD 67 (A) or GABA (B-C) surrounded the region of the developing paraventricular nucleus of the hypothalamus (PVN) at embryonic ages. At E13 (A), E15 (B), and E17 (C) in the mouse, the PVN region is one of two hypothalamic regions where GABA is found surrounding the nucleus in development. The ventromedial nucleus of the hypothalamus (VMN), the other nuclear group where this has been found, is shown within the images of panels A and B. By adulthood GABAergic fibers have moved into the region of the PVN and VMN (data not shown). At the center of each image is the third ventricle (scale bars = 100μm).