Hippocampal lesions and negative patterning in pigeons

A number of studies have shown that rats with hippocampal lesions are impaired on the negative patterning task, thereby supporting the view that the hippocampus may be important for configural learning. We trained 8 control sham-operated pigeons and 9 pigeons with bilateral hippocampal (hippocampus and area parahippocampalis) lesions on a negative patterning task to respond in the presence of a houselight or tone presented individually, and to withhold responding in the presence of the houselight and tone presented simultaneously. Pigeons with hippocampal lesions learned the task at the same rate as did control unoperated pigeons. This finding is in line with recent reports that the hippocampus is not critical for performance of the negative patterning task.