Shift from fibrillar to nonfibrillar Aβ deposits in the neocortex of subjects with Alzheimer disease

Jerzy Wegiel, Matthew Bobinski, Michal Tarnawski, Jerzy Dziewiatkowski, Eirene Popovitch, Margaret Bobinski, Boleslaw Lach, Barry Reisberg, Douglas C. Miller, Susan De Santi, Mony J. De Leon

Research output: Contribution to journalArticlepeer-review

10 Scopus citations


A morphometric study of amyloid-β-positive plaques in the neocortex of eight non-demented people from 68 to 82 years of age and 17 subjects with late-stage Alzheimer disease (GDS stage 7/FAST stages 7a-f) from 73 to 93 years of age shows a shift from prevalence of fibrillar plaques to prevalence of nonfibrillar plaques. In the aged, non-demented subjects, about 4/mm2 plaques are detectable in the neocortex, and the majority are fibrillar plaques. Specifically, 64% of plaques in the neocortex of the normal aged subjects were found to be classical fibrillar and Thioflavin-S-positive bright primitive plaques. A lower percentage of pale primitive plaques (35%) and diffuse plaques (1%) was observed, reflecting the relatively small proportion of plaques that are poor in thioflavin S-positive fibrils. The numerical density of plaques in the severe stage of AD increases to about 41/mm2. Severely demented subjects appear to maintain an active process of fibrillar plaque formation. This is reflected in the presence of 3% fibrillar classical and 27% bright primitive plaques. Severely demented subjects also manifest plaque degradation, reflected in the presence of 22% pale primitive and 48% diffuse-like Thioflavin S-negative plaques. Comparable percentages of classical fibrillar plaques in nondemented subjects and in the end stage of disease suggest that once activated, the process of fibrillar plaque formation persists at a somewhat stable rate during the whole course of brain amyloidosis.

Original languageEnglish (US)
Pages (from-to)49-57
Number of pages9
JournalJournal of Alzheimer's Disease
Issue number1
StatePublished - 2001
Externally publishedYes


  • Alzheimer disease
  • Diffuse plaques
  • Fibrillar plaques
  • Morphometry

ASJC Scopus subject areas

  • Neuropsychology and Physiological Psychology


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