Spontaneous locomotor activity and food and water intake in rats with medial amygdala lesions.

Locomotor activity was studied with the method of electromagnetic activity meters, before and after operation in rats bilaterally lesioned in medial amygdala, and in a sham-operated control. Two activity tests were performed daily. In the first test spontaneous activity was recorded for a 30 min period without access to food or water. The second test measured 12 h of nocturnal activity with full access to food and water. Bilateral destruction of the medial amygdala resulted in an increase of locomotor activity in the 30 min test and a decrease in locomotor activity in the 12 h test. Postoperative decrease in food and water intake and body weight were only transient. These results point to a participation of the medial amygdala in the complex mechanism of locomotor activity and alimentary motivation.