NEUROANATOMICAL STUDY OF OBESE AND NON-OBESE HYPOTHALAMIC MONKEYS IN RELATION TO FOOD INTAKE, LOCOMOTOR ACTIVITY, AND TEMPERATURE REGULATION

Abstract

Obesity, hypoactivity, and an impairment of ability to maintain body temperature in moderate cold were encountered in combination, or separately, following experimental bilateral destruction between the optic chiasma and the mammillary bodies in the hypothalamus. An impairment in the ability to regulate temperature against cold was present in all six obese monkeys of this series following lesions which destroyed extensively the periventricular system and the paraventricular and dorsomedial hypothalamic nuclei. This was associated with hypoactivity in two out of three obese animals in which this function was studied. Obesity occurred without any increase in food intake in three animals in which the diet was controlled; only one of these showed a slight hyperphagia when free access to food was permitted. One non-obese animal showed marked hyperactivity associated with a voracious appetite and an inability to regulate against cold following small bilateral lesions in the central area of the hypothalamus.