Hippocampal Striatal Interactions in a Picture Memory Task

The organization of learning and memory in the brain is widely held to be made of functionally distinct memory systems. It is important to identify how these complex neural systems interact with one another. This thesis investigates the interaction of the systems involved to solve a simple discrimination task. Acquisition of this task can be supported by hippocampal and non-hippocampal systems. The purposes of these experiments are: (1) to identify the non-HPC system supporting picture discrimination, and (2) characterize how the systems interact. Rats received various lesions either before or after training and assessed on acquisition or retention performances. The results indicate that picture discriminations can be acquired by hippocampal or striatal systems, and that the medial prefrontal cortex is not involved in an essential way. Furthermore, the findings suggest that a competitive interaction occurs supporting the idea that the hippocampus interferes with striatal acquisition of the picture discrimination task. iv Table of Contents 1.