Fig. 2

Relative abundance of ptau in hippocampus and neuroanatomically connected brain regions in K18-tau aggregate seeded PS19 mice carrying human APOE alleles. Semi-quantitative analyses of ptau transmission patterns along neuroanatomic pathways represented by AT8 immunostaining is shown from K18-tau aggregate seeded PS19 mice homozygous for human APOE alleles (B6N2 generation). Pathology severity was assigned scores on a scale of 0 (no pathology) to 3 (high pathology) and color-coded onto heat maps (a, c, e). The injected hemisphere (ipsilateral, ‘IPSI’) is shown on the left and non-injected (contralateral, ‘CONTRA’) hemisphere is depicted on the right for each heat map. Three coronal planes were examined at bregma locations of 0.97, − 2.03 (site of injection), and − 3.51 mm. Boxed diagrams on the right show different brain regions neuroanatomically connected to the dorsal hippocampus via either anterograde or retrograde pathways (left pointing arrows) or both pathways (double-headed arrows) (b, d, f). Brain regions showing AT8 immunoreactivity are indicated by bold and underlined text in the boxes (b, d, f). See also Additional file 1: Fig. S1. n = 3–4 mice/group