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Show THE ROLE OF THE HIPPOCAMPUS AND PARIETAL CORTEX IN METRIC AND TO-POLOGICAL INFORMATION PROCESSING Naomi Goodrich (Ray Kesner) Department of Psychology The hippocampus and parietal cortex (PC) process spatial information and several models suggest they process different components of spatial information (i.e., metric and topological relationships between objects). Understanding how the hippocampus and PC interact during the acquisition of spatial information and how each region processes this information is important to understanding how different components of the spatial information are processed by the brain. It has been proposed that the hippocampus processes metric information, whereas the PC processes topological information. Variations on a spatial learning task will demonstrate how the hippocampus and PC process spatial information. After either PC or hippocampus lesions, Long-Evans rats completed two variations of a reaction-to-change task on a cheese board. The metric task consisted of two objects placed 68 cm apart on the cheese board and after habituation, the objects were moved closer or further apart. The topological task consisted of four objects placed on a cheese-board. After habituation the front two objects were switched. Next, after habituation the back two objects were switched. In comparison to control animals, PC lesioned rats were impaired on the topological task alone and dorsal hippocampus lesioned rats were impaired on both the metric task and topological tasks. The data suggests that the hippocampus is necessary for both metric and topological representations and the PC is necessary for topological representations. Further research is needed to determine why the hippocampus is necessary for both components of spatial information processing. |