Images showing thionin staining for neuroanatomical reference (left column), silver grains corresponding to Ar mRNA (right column). Low Ar expression was observed in the piriform area (PIR, A-B), dorsal and ventral anterior cingulate area (ACAd and ACAv, C-D), induseum griseum, septohippocampal nucleus (IG and SH, E-F), and CA3, and high in field CA1 and CA2 (G-H). Abbreviations: ACB, nucleus accumbens, ccg, genu of corpus callosum, DG, dentate gyrus, lot, lateral olfactory tract, LS, lateral septal nucleus, MOs, secondary motor area, OT, olfactory tubercle. Scale bar = 200 µm.