CONTEXTUAL CONTROL OF CONDITIONED RESPONDING IN RATS WITH DORSAL HIPPOCAMPAL-LESIONS

The control exerted by contextual cues over classically conditioned re sponding was assessed for rats with electrolytic lesions of the dorsal hippocampus and sham-operated controls. In 3 experiments the rats rec eived initial training with 2 reinforced cues, each presented in its o wn distinctive context, followed by a nonreinforced test in which the cues were presented in the other context. Both control and operated su bjects showed context specificity, as evidenced by less vigorous respo nding to these cues than to cues presented on test in their original c ontexts. The groups did not differ in their ability to learn an explic it discrimination in which a given cue was reinforced in one context a nd nonreinforced in a different context (although the groups did diffe r on a simple autoshaping task). It is concluded that a special role f or the hippocampus in the contextual control of conditioned responding still remains to be demonstrated.