Preserved negative patterning and impaired spatial learning in pigeons (Columba livia) with lesions of the hippocampus

Pigeons (Columba livia) with bilateral electrolytic lesions of the hippocam pus and area parahippocampalis were compared with control pigeons on 2 task s: negative patterning and delayed spatial alternation. Negative patterning demands configural stimulus representations for its successful solution. T he only effect of hippocampal lesions on this task was an increased respons e rate to the rewarded stimuli. On the delayed spatial alternation task, hi ppocampal birds showed deficits relative to controls. Differences in the re sults of prior studies on negative patterning appear to be due to different response requirements to the nonreinforced stimuli. These results are cons istent with prior work with rats and suggest that the avian hippocampus is essential for spatial memory and response inhibition but is not involved in configural learning.