Experimentally measured aggregate per synaptosome distributions (bars), for (A and B) human and (C and D) mouse samples. The predicted Poisson distribution, based on either matching the fraction of synaptosomes without aggregates (solid gray line) or the average number of aggregates per synaptosome (dashed black line) is shown overlaid. For all except the data from human AD samples (B) the 2 predicted distributions overlap with each other and match the data. For the human AD samples, there are more synaptosomes with higher numbers of aggregates than would be expected based on the total fraction of synaptosomes that contain aggregates (compare bars to solid gray line), indicating that the appearance of individual aggregates are not independent events as in the other 3 datasets.
