A reevaluation of the role of the lateral hypothalamus in behavioral temperature regulation.

Rats exposed to the cold (-9 degrees C) were trained to depress a lever to obtain pulses of infrared heat. Half of the animals received bilateral electrolytic lesions of the lateral hypothalamus and half were sham operated. Lesioned and control animals performed similarly postoperatively and responded appropriately to changes in reward duration and intensity. Thus, lateral hypothalamic lesions do not impair behavioral thermoregulation. Despite normal behavioral heat intake, body temperature of the lesioned rats fell significantly during the sessions, which can be attributed to an impairment in metabolic heat production due to the lesions.