Fig. 2. Quantitative, longitudinal transmission electron microscopy (TEM) delineates basal laminar deposit (BLamD) progression in WT and R345W^+/+ mice.

(A, B) TEM analysis of WT (A) or R345W^+/+ (B) mice at 4 mo intervals ranging from 4–20 mo. Representative images of ~16 FOVs per mouse, n = 6 mice/genotype and age group (3 male, 3 female) except for 20 mo mice. n = 3 females/genotype at 20 mo. Scale bar = 2 μm. Area highlighted in red designates the tracing used to quantify BrM and BLamDs (if present). Images taken at 2,500x magnification. Scale bar = 2 μm. V = vacuole. (C, D) Quantitation of BLamD size (μm²/FOV) (C) and percent sub-FOVs (D) that contain at least one BLamD (see Materials and Methods for in-depth information on definition and quantitation of BLamDs). Data in (C) are presented as violin plots showing the median and quartiles. Data in (D) are presented as percent of total FOVs counted for each age/genotype. Comparative analysis performed using Mann-Whitney tests. * p < 0.05, **** p < 0.0001. Note: The WT TEM image and WT BLamD quantification are identical to that shown later in Fig. 10B–D.