Autoradiography of 125I-MPPI binding in 5-HTT mutant mice. Left, Wild-type 5-HTT mice (5-HTT +/+). Middle, Heterozygous 5-HTT knock-out mice (5-HTT +/−). Right, Homozygous 5-HTT knock-out mice (5-HTT −/−). The brain sections from top to bottom are striatum (bregma 0.98–0.50 mm), medium hypothalamus (bregma 0.7 to −1.06 mm), caudal hypothalamus (bregma −1.34 to −1.94 mm), and midbrain (bregma −4.36 to −4.84 mm). ACo, Anterior cortical amygdaloid nucleus; AH, anterior hypothalamic nucleus;BLA, basolateral amygdaloid nucleus, anterior;BMA, basomedial amygdaloid, anterior;CA1–CA3, CA1–CA3 field of hippocampus;CeC, central amygdaloid nucleus, capsular division;CeMAD, central amygdaloid nucleus, medial anterodorsal;CeMAV, central amygdaloid nucleus, medial anteroventral;DEn, dorsal endopiriform nucleus; DG, dentate gyrus of hippocampus; DMN, dorsomedial hypothalamic nucleus; DRN, dorsal raphe nucleus;La, lateral amygdaloid nucleus; Ld, lambdoid septal zone; LH, lateral hypothalamic nucleus;LSI, lateral septal nucleus, intermediate;MeA, medial amygdaloid nucleus, anterodorsal;MRN, medial raphe nucleus; MS, medial septal nucleus; PVN, paraventricular hypothalamic nucleus; VMN, ventromedial hypothalamic nucleus.