Hyperstriatal Lesions and Short-Term Retention of Non-Visual Information in Pigeons

Short-term retention of non-visual information was investigated using three series of hyperstriatal-lesioned and unoperated control pigeons. Neither retention (Experiment 1) nor acquisition (Experiment 3) of go/no-go alternation was disrupted by the lesions. Similarly, Experiments 2 and 5 failed to detect significant disruption of either retention or acquisition of spatial alternation. Increases in the retention intervals used in these tasks reduced accuracy in both groups but did not differently affect hyperstriatal as opposed to control performance. A lasting deficit was, however, obtained in a delayed-response task (Experiment 4), but this deficit, which was independent of retention interval, appeared to be the result, not of a disruption of memory, but of an exaggerated perseverative tendency. Experiment 6 confirmed that all three series of hyperstriatal birds showed disruption of reversals of a spatial discrimination. It is concluded that hyperstriatal lesions do not disrupt memory processes, and the hypothesis that hyperstriatal damage induces perseveration of central sets is discussed.