Cortical, hippocampal, and striatal mediation of schedule-induced behaviors

The sequential occurrence of licking, locomotor activity, entries into the food magazine (panel pressing), and nonreenforced lever pressing engendered by a periodic schedule of food presentation were measured in each 60-s interreenforcement interval in normal and brain-damaged rats. The development of these responses was measured over 20 days in different groups of food-deprived rats that had received aspirations of the hippocampus, small lesions of the cortex overlying the hippocampus (hippocampal-operated control group), decortication, or 6-hydroxy-dopamine lesions of the caudate nucleus or nucleus accumbens. All lesions produced distinctive patterns of change in the measured behaviors, and dissociations as well as similarities in their effects were evident. These results are discussed with respect to dissociations in the motor and motivational effects of the various lesions and in terms of contemporary hypotheses of schedule-induced behavior.