A diagram showing the dissected region containing the PVH. Immediately after decapitation, the brain was removed from the skull and placed on a rat-brain slicer. A 2-mm coronal section containing the hypothalamic region was cut on ice with a stainless steel blade. A triangular tissue block, containing the entire PVH, was removed from each side of the section on ice, as indicated in the diagram. A representative photomicrograph, taken at the midpoint of the rostro-caudal extent of the tissue block, is shown in the diagram. Scale bar, 1 mm. III, third ventricle; OT, optic tract.