Novel method to quantify neuropil threads in brains from elders with or without cognitive impairment

Pathological alterations in dendrites and axons (i.e., neuritic pathologies ) occur in the normal aging brain as well as in brains from elders with mil d cognitive impairment and neurodegenerative dementia. These alterations ma y correlate with clinical measures of cognitive abilities, but the contribu tion of neuropil threads (NTs), which constitute 85-90% of cortical tau pat hology, has not been clear because of the lack of quantitative methodologie s. We combined quantitative fractionation and image analysis to devise a st rategy for measuring the burden of tau-rich NTs in the entorhinal and perir hinal cortex of brains from elders with and without cognitive impairment, i ncluding dementia due to A[Alzheimer's disease (AD). On the basis of data p resented hel-e using this novel strategy, we conclude that this quantitativ e imaging technique will facilitate efforts to determine the behavioral cor relations of neuritic lesions in AD and other brain disorders.