VISUAL-CORTEX IN ALZHEIMERS-DISEASE - OCCURRENCE OF NEURONAL DEATH AND GLIAL PROLIFERATION, AND CORRELATION WITH PATHOLOGICAL HALLMARKS

Visual areas 17 and 18 were studied with morphometric methods for numb ers of neurons, glia, senile plaques (SP), and neurofibrillary tangles (NFT) in 13 cases of Alzheimer's disease (AD) as compared to 11 contr ols. In AD cases, the mean neuronal density was significantly decrease d by about 30% in both areas 17 and 18, while the glial density was in creased significantly only in area 17. The volume of area 17 was uncha nged in AD cases but its total number of neurons was decreased by 33% and its total number of glia increased by 45% compared to controls. In AD the number of SP was similar in areas 17 and 18, while that of NFT was significantly higher in area 18. The number of neurons with NFT w as only 2% in area 17 and about 10% in area 18. The discrepancy betwee n the loss of neurons and the amount of NFT suggests that neuronal los s can occur without passing through NFT degeneration. The deposition o f SP was correlated with glial proliferation, but not with neuronal lo ss or neurofibrillary degeneration.