Histological verification of recording sites in caudal anterior cingulate cortex. Tetrode placements extended from the genu of the corpus callosum (gcc) to ∼140 μm anterior to bregma. cc, Corpus callosum; Cg1, Cg2, anterior cingulate gyrus areas 1 and 2, respectively; cg, cingulum; M2, secondary motor cortex.