Effects of hyperstriatal lesions on within-day serial reversal performance in pigeons

In Experiment 1, 12 pigeons performed each day for 17 days 3 serial reversals of a simultaneous color discrimination; 6 birds were then given hyperstriatal lesions, and 6 birds were sham operated. Analysis of the effects of lesions on postoperative reversal performance supported 2 hypotheses: first, that the hyperstriatum contains a mechanism involved in the generation of inhibition, and second, that minimal inhibition is generated (in intact birds) in the first of each day's reversals. Experiment 2 investigated the effects of hyperstriatal lesions on serial position reversal; results again supported the notion that the hyperstriatum is involved in response inhibition. Contrasts between the effects obtained in the 2 experiments suggested that inhibition plays a more central role in position, as opposed to color, reversals.