Effects of prefeeding on the DRL preformance of rats with septal lesions.

Two experiments reported the effects of prefeeding normal and septal rats prior to their daily sessions on a differential reinforcement of low rates (DRL-20) schedule. Prefeeding reduced responses and increased reinforcements in the case of septal animals, regardless of the level of body weight. In the case of normal animals, prefeeding led to a decrease in responding and an increase in the number of reinforcements obtained only when the animals were at 85% of ad-lib levels, prefeeding, although it decreased responding, also decreased the frequency of obtained reinforcements. These results implied an impairment in normal animals in the discrimination of response feedback by stimulation arising from stomach distention.