GREATER METABOLIC-RATE DECREASES IN HIPPOCAMPAL-FORMATION AND PROISOCORTEX THAN IN NEOCORTEX IN ALZHEIMERS-DISEASE

Neuropathological studies of Alzheimer's disease (AD) have found patho logical changes in some cytoarchitectural regions and relative sparing in others. Positron emission tomography (PET) studies have also shown selective decreases in glucose metabolic rates but have generally foc used on whole brain lobes or geometrically derived regions of interest . In this report, a template of Brodmann areas, derived from a whole b rain histological section atlas, was used to analyze PET findings from 34 AD patients and 16 control subjects matched for age, sex, and educ ational level. AD patients had lowest glucose metabolic rates in limbi c areas of the temporal lobe and other proisocortical areas higher rat es in frontal lobe and unimodal association areas, and relative sparin g of parietal/occipital lobes and motor/sensory cortices. Analysis of variance revealed larger effect sizes when AD and control subjects wer e compared on metabolic rate for cortical type than for lobe. These fi ndings, which parallel neuropathological studies of regional distribut ion of neurofibrillary tangles in AD, suggest that vulnerability is gr eatest in cortical areas that are in closer synaptic contact with limb ic areas.