title: Brain stimulation reward in the lateral hypothalamic medial forebrain bundle: mapping of boundaries and homogeneity.
abstract: The boundaries and relative fiber concentration of the brain stimulation reward (BSR) sustaining system coursing through the lateral hypothalamic medial forebrain bundle (MFB) were mapped using a dorso-ventral moveable electrode. High response rates for BSR were found in a region extending dorso-ventrally from the zona incerta (ZI) to the base of the brain and medio-laterally from the fornix to the medial tip of the internal capsule (IC). Self-stimulation associated with perifornical area and self-stimulation associated with the tip of the internal capsule were mixed with aversion and forced movements, respectively. Current intensity threshold variations suggest: (i) that the reward system has a well-defined dorsal boundary ventral to the ZI, and (ii) that the core of the MFB contains a relatively higher concentration of reward relevant fibers than do its lateral, medial, dorsal and ventral components. No evidence was seen of independent mid-lateral and far-lateral MFB systems, though independent BSR sites in the dorsomedial and ventromedial hypothalamus were seen.
mesh_terms: D000818:Animals; D004558:Electric Stimulation; D007031:Hypothalamus / Q000502:physiology*; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D012201:Reward