Testing for material-specific effects in long-term memory: evidence from amnesia and functional neuroimaging.

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A number of diseases, such as epilepsy, dementia, stroke and viral infections, result in memory difficulties, in particular our ability to remember events from the past (long-term memory, LTM). Two regions, the hippocampus and perirhinal cortex, are thought to make an important contribution to LTM as damage to either of these areas results in memory problems. It is unclear, however, whether these two brain regions work together to support LTM, or whether they play distinct roles, particularly for visual memory. The proposed research addresses this question by testing whether the hippocampus is necessary for scene, but not face or object, memory, and if the perirhinal cortex is involved in face and object, but not scene, memory. Two different techniques are used to address this question. First, we ask patients with damage to the hippocampus and/or perirhinal cortex to perform memory tasks in which they are required to remember whether they have previously seen items from our three visual categories. We wish to know whether damage to these two brain structures results in distinct patterns of memory impairment. Second, we ask healthy participants and patients to undertake memory tasks in an MRI scanner; this allows us to pinpoint which parts of the brain are recruited during memory processing, and to see if the hippocampus and perirhinal cortex show distinct patterns of activity for different visual categories. The findings from these two parts of the grant will be used to refine current ideas about how the hippocampus and perirhinal cortex support LTM, and to develop new models and predictions, that further our knowledge of how damage to these brain areas results in memory difficulties across different diseases.The final part to the grant aims to use the information we gather from our patient and imaging studies to improve memory in individuals with hippocampal damage. We propose to show that if patients concentrate on the individual details of objects this will help boost their memory for words referring to these objects. If we can demonstrate evidence of transfer from visual to verbal stimuli, this will help clinicians and patients develop better strategies for improving memory in everyday situations.