FUNCTIONAL-HETEROGENEITY OF THE MONKEY LATERAL HYPOTHALAMUS IN THE CONTROL OF FEEDING

Regional differences in the effects of electrical (ES) and chemical stimulation on execution of a bar-press feeding task, and in neuronal activity related to feeding, glucose sensitivity, and odor responsiveness were examined in the lateral hypothalamic area (LHA) of monkeys. In satiated animals, ES of the far lateral and ventral LHA induced bar-press feeding. In hungry animals, ES of the dorsal LHA suppressed the feeding task only during the stimulation period, but prolonged feeding suppression that occurred after ES of the ventromedial LHA. Microinjection of Na-glutamate into LHA sites where ES was effective in suppressing feeding had no effect, but it was effective in the medial hypothalmus. Glucose-sensitive (GS) neurons decreased in activity during bar pressing and/or during the ingestion period. Glucose-insensitive (GIS) neurons showed a cue-related excitation more often than GS neurons. Odor-responding GS and GIS cells were localized in ventromedial and lateral LHA sites, respectively. The present study suggests the regional heterogeneity of the LHA in feeding regulation, depending on both hunger and satiety states.