Amygdaloid Pathology in Alzheimer's Disease: Qualitative and Quantitative Analysis

Abstract
Pathologic evaluation of the amygdala in Alzheimer''s disease (AD) revealed, as compared to controls, a 43.7% decrease in total amygdaloid area, with areal reductions in lateral and basolateral nuclei of 52.9 and 54.3%, respectively. Thioflavin-S stained sections of the amygdala demonstrated a topographic distribution of neuritic plaques, with classic plaques located primarily in accessory basal, medial basal and cortical nuclei, whereas diffuse plaques predominated in the lateral nucleus. Neurofibrillary tangles were also topographically distributed and were up to 10 times more numerous than neuritic plaques. Tangle-bearing neurons predominated in cortical, medial, accessory basal and medial basal nuclei, whereas extracellular tangles characterized lateral and basolateral nuclei. These results are interpreted in light of known anatomical connections and suggest a predictive pattern of pathology in AD.