Is the medial temporal lobe functionality heterogeneous for familiarity and recollection. (360G-Wellcome-094597_B_10_Z)

We will recruit 90 hypoxic patients complaining of memory problems, from whom 60 participants will be selected on the basis of recall and/or item recognition memory impairments with damage confined to the medial temporal lobes. MRI measures of regional brain volumes in key structures, fibre tract integrity (DTI) and cerebral blood flow (CBF) will be obtained. Patients will be grouped on the basis of whether their damage primarily involves the hippocampus, perirhinal cortex, parahippocampal corte x, or more widespread medial temporal lobe volume loss. Several procedures will be used for measuring recollection and familiarity memory for different kinds of information, including structural equation modelling, in these patients and healthy controls. We will explore recollection and familiarity both for rapidly learned post-morbid memories and for frequently rehearsed, pre-morbid memories. These studies will be complemented by functional MRI (fMRI) investigations. By combining detailed analy sis of memory performance and brain imaging data, we will elucidate the extent to which the hippocampus, perirhinal cortex and parahippocampal cortex have differing roles in the recollection and familiarity of premorbid and post-morbidly acquired memories involving different kinds of information. More specifically, we seek to resolve the long-standing dispute about the role of the hippocampus in familiarity and recollection.