Fig. 21B.Overview of the major afferent pathways to the hypothalamus. (B) Schematic organization of limbic afferents to the hypothalamus via the fornix (fx), stria terminalis (st), stria medullaris (sm), and olfactory tract. Axons enter the rostral portion of the hypothalamus before coursing throughout its entire extent. aap = amygdalofugal and amygdalopetal components of the ansa peduncolaris; ac = anterior commissure; Ah = Ammon horn; al = ansa lenticularis; am = amygdala; ap = ansa peduncularis; ATn = anterior thalamic nucleus; cc = corpus callosum. CN = caudate nucleus; CS = corpus striatum; df = dentate fascia; fl = fasciculus lenticularis; fr = fasciculus retroflexus; ft = fasciculus thalamicus; fx = fornix; H1 = field H1 of Forel; H2 = field H2 of Forel; ha = habenula; hipp = hippocampus; HYP = hypothalamus; ic = internal capsule; iTp-ap = inferior thalamic peduncle of the ansa peduncularis; LTn = lateral thalamic nucleus; mb = mammillary body; MFB = medial forebrain bundle; mst = mammillo-subthalamic tract; MTn = medial thalamic nucleus; mtt = mammillo-thalamic tract; olf-a = olfactory area; olf-n = olfactory nerve; olf =olfactory tubercle; opt = optic tract; pir = piriform cortex; pvs = periventricular system; RF = reticular formation of the brainstem; sa = septal areas; SN = substantia nigra; Sub = subthalamus; zi = zona incerta; III = third ventricle. (From Toni R, Malaguti A, Benfenati F, Martini L: The human hypothalamus: a morphofunctional perspective. J Endocrinol Invest 27 (supp to n.6), 73-94, 2004.)