Fig. 3

Prnp deletion rescues DKI-dependent synapse density reduction measured by SV2A PET. A, B Voxel-wise analysis t value map comparing averaged [18F] SynVesT-1 PET in 15-month-old mouse brains. Activity is expressed as SUVR (normalized to cerebellum). Color scale represents magnitude of difference in activity in that genotypic comparison. C ROI-based comparison of hippocampal [18F]SynVesT-1 SUVR (normalized to cerebellum) in WT, Prnp^−/−, DKI and DKI; Prnp^−/− mice. DKI mice demonstrate decreased hippocampal synaptic density compared to WT, while Prnp knockout restores hippocampal synapse density in the DKI background. Data are graphed as mean ± SEM, analyzed by ordinary one-way ANOVA with Dunnett’s multiple comparisons test, * P < 0.05, **P < 0.01, n = 36 for WT, n = 12 for Prnp^−/−, n = 22 for DKI, and n = 12 for DKI; Prnp^−/−