STUDIES OF WORKING-MEMORY USING (18)FDG-POSITRON EMISSION TOMOGRAPHY IN NORMAL CONTROLS AND SUBJECTS WITH EPILEPSY

We have studied three groups of subjects with a working memory paradig m, using (18)FDG-PET. Controls show the greatest increase on uptake in dorsolateral prefrontal cortex, basal forebrain and angular gyrus. A group of subjects with focal frontal epilepsy did not show increases c ompared to a control task of attention. Primary generalized epilepsy s ubjects show the greatest changes in angular gyrus, dorsal temporal, m edial frontal and parietal regions. Factor and regression analyses ext end these observations and show reliance of both patient groups on the medial and inferior temporal lobe. We propose that the normal network of working memory is disrupted by these two forms of epilepsy and dif ferent networks are accessed. Declarative memory may be used as a comp ensatory system, which results in decreased performance.