Lateral hypothalamic aphagia: motor failure or motivational deficit?

Abstract

Recovery of feeding was studied in rats with lateral hypothalamic lesions. The animals were given the choice of feeding themselves by mouth or by pressing a bar for injections of food into their own stomachs. Foods of high palatability were offered for oral feeding. A method of intragastric self-injection was employed that permits the animal to eat without making the feeding movements and without tasting or smelling the food. The lesions typically produced a complete failure to eat for from 1 to 15 days. During the period of complete aphagia all animals tested made the movements of feeding when food was put in their mouths. In all cases, feeding by mouth returned before bar pressing and intragastric feeding. A recent conflicting experiment is discussed. It is concluded that rats with lateral hypothalamic aphagia can eat but do not because they are not hungry.