Fig. 6

Tau-SAA seeding activity in middle frontal gyrus gradually increased with Braak stage (0-VI) and reflected the load of pathological Tau forms. a Time to threshold (TTT) values from Tau SAA of middle frontal gyrus homogenates (see Additional file 1: Table S4) diluted 10−5. Dotted line: separating fast-seeding (TTT < 200 h) and slow-seeding samples (TTT of 200–430 h). Crosses: non-seeding samples (TTT of ≥ 430 h). Dots depict the mean TTT values of technical triplicates. Bars represent the group medians + interquartile range. Statistical comparisons by Kruskal–Wallis test with Dunn’s multiple comparisons correction. *p < 0.05, **p < 0.01, ***p < 0.001. b–e ELISA results of aggregated Tau, sarkosyl-insoluble Tau, pTau212/214, and total Tau. Dots depict the mean of technical duplicates. Crosses in indicate values below the limit of detection (LOD, dotted line) and were set to one third of the LOD. f–j Stratification of samples into fast- (TTT <200 h), slow- (TTT of 200–430 h) and no seeding (TTT of ≥ 430 h) based on Tau SAA. Braak stages are colored as indicated in a–e. Vertical lines represent the group medians. Statistical comparisons by Kruskal–Wallis test with Dunn’s multiple comparisons correction. *p < 0.05, **p < 0.01, ***p < 0.001. Cohort 3 is described in detail in Table 3 and Additional file 1: Table S4