Location and labeling of identified anterior cingulate cortex neurons with neurobiotin. (A) Location of neurons recorded in the anterior cingulate cortex (ACC). Coronal sections from the caudal to rostral regions of the ACC (i.e., bregma 2.16, 2.76, 3.72 mm) show the electrophysiological recording sites. Squares and circles indicate CRD-excited ACC neurons in control rats and CCK-8 treated rats, respectively. Cg, cingulum; Cg1, cingulate cortex, area 1; Cg2, cingulate cortex, area 2; M2, Secondary motor cortex; PrL, prelimbic cortex. (B) Microphotograph of neurons in the ACC labeled with neurobiotin a, thionine-stained coronal section shows the distribution of CRD-excited neurons in the ACC. b, higher magnification of the neurobiotin-labeled pyramidal ACC neuron in a (arrow). Scale bars: a, 250 μm; b, 50μm.