Detection of intraneuronal Aβ and APP/CTFs. a) To measure the overlap coefficient of different antibody binding sites, the signals were separated from background using a brightness criterion and made binary. The two images were then superimposed; the M1 coefficient represents the overlap (yellow) divided by the total green signal (yellow + green). The M2 coefficient represents the overlap divided by the total red signal (yellow + red). b-d) Representative high-magnification confocal micrographs depicting co-localization between pab27576 (red) and b) McSA1 (green) binding sites, c) MOAB-2 (green) and d) Nu1 (green) in lamina V neurons of the parietal cortex, at the pre-plaque stage (3 month-old transgenic rats). Note the lack of complete overlap between Aβ- and APP/CTF-specific signals. Scale bar = 10 μm.