Effects of hippocampal lesions on acquisition and retention of spatial learning in zebra finches

We tested the role of the hippocampus in spatial memory of zebra finches. The birds were trained to find the location of a food site among four identical feeders arranged on the aviary floor. Extra-maze cues were present. The birds had to perform the task from four different starting points. Successful visits and the time to find the food were recorded. Hippocampal lesions made before acquisition led to a decrease in correct choices. Hippocampal lesions following training disrupted the retention of the spatial memory. Surprisingly, birds with hippocampal damage reached the food as quickly as intact birds, but they needed more visits to find the correct feeder. Therefore, the birds with hippocampal damage used an alternative, nonspatial memory-based strategy to find the food. (C) 2004 Elsevier B.V. All rights reserved.