Morphological substratum of lateral hypothalamic aphagia and adipsia: A mapping study in the rat

Abstract

The purpose of the experiment was to map an area involved in the regulation of food and water intake within the region of the lateral hypothalamus (LH), the adjacent subthalamus and antero-ventral midbrain. The strategy was to make a series of electrolytic lesions, varying in size and localization and to correlate the size of the damage to particular structures occupying the region with the presence and intensity of ingestive disturbances. The highest correlation was found between the presence and duration of aphagia and adipsia and the size of damage to the tuberal part of LH. Even large lesions localized anteriorly or posteriorly to this region gave only moderate ingestive deficits. Surprisingly, total or almost total disruption of the nigro-striatal bundle at the level of the anterior or posterior LH evoked only slight, if any, disturbances in food and water ingestion. No correlation was found between the duration 01 aphagia and adipsia and the size of damage to zona incerta, fields of Forel, capsula interna, leimniscus medialis, ventral tegmental area and substantia nigra. Our results did not confirm pharmacological data concerning dopamine depletion-induced aphagia and adipsia. It seems that the role of the nigro-striatal system for LH ingestive impairments is still to be cleared up.