A quantitative electron microscopic study of the ageing human cerebral cortex

Summary A recent quantitative electron microscopic study of biopsy samples of the cerebral cortex of neurologically normal individuals, aged between 15 and 54 years, has shown that atypical inclusions are present in neuronal and glial processes in small but appreciable numbers (Rees). It would be of interest to know whether these inclusions accumulate with age. This study therefore applied the same quantitative methods used in the previous study, to autopsy samples of frontal and temporal cortex from 3 non-demented ageing human brains (70–76 years).The results showed that in the areas of cortex examined, the number of inclusions in neuronal processes did not increase with age. However, the number of dense deposits in the cell bodies and processes of oligodendrocytes did increase significantly with age. In agreement with previous studies corpora amylacea were found in astrocytic processes. Senile plaques were not observed.