Food and water intake following lesions or electrical stimulation of the amygdala

Abstract

In the first experiment, very small bilateral lesions were placed into the posteroventral amygdala of 12 rats. Food and water intake was recorded for 6 weeks prior to the operation and for 12 weeks following it. Water consumption rose sharply immediately after the operation and remained near the maximal level for 12–16 days. Food intake increased gradually, reaching a maximum after 3–4 weeks. Feeding and drinking returned to near-normal within the 12-week observation period. In the second experiment, electrodes were implanted into anterior, medial, and posterior portions of the ventral amygdala. Electrical stimulation of anterior points inhibited food intake but increased water consumption. Stimulation of the medial placements produced no consistent effect. Both feeding and drinking behavior were inhibited during and immediately following the stimulation of posterior points. Lesions in the anterior area increased food intake but reduced water consumption. Medial lesions reduced water intake but had no reliable effect on feeding behavior. Posterior lesions produced hyperphagia and hyperdipsia. The lesion effects appeared to be permanent.