A behavioural analysis of visual pattern separation ability by rats : effects of damage to the hippocampus

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Spanswick, Simon C.
University of Lethbridge. Faculty of Arts and Science
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Lethbridge, Alta. : University of Lethbridge, Faculty of Arts and Science, 2005
Different events usually contain similar elements that can contribute to interference during memory encoding and retrieval. The hippocampus (HPC), a structure that is critically involved in some forms of memory, has been hypothesized to reduce interference between memories with overlapping content, thus facilitating correct recall. Pattern separation is one hypothetical process whereby input ambiguity is reduced. Here we test the hypothesis that the HPC and/or dentate gyrus (DG) are important for pattern separation by measuring performance by rats with damage in tasks that require discrimination between visual stimuli that share systematically varying numbers of common elements. Rats with HPC damage were slower to resolve discriminations with minimal degrees of overlap. Lesions of the DG did not affect the ability of rats to deal with overlap, suggesting a dissociation between the HPC and DG. Our results provide partial support for the idea that the HPC contributes to the pattern separation process.
ix, 84 leaves : ill. ; 29 cm.
Dissertations, Academic , Memory -- Physiological aspects , Memory -- Research , Rats as laboratory animals , Hippocampus (Brain) -- Physiology