Fig. 4. Scatter Plots of the Association between Age at Death and Quantitative Measurements of P-tau Density.

The sample size was reduced to 176 as this represents the sample with available quantitative data across all three brain regions at the time of this data freeze (July 2019). Older age was associated with greater quantitative p-tau density for each region assessed (p’s < 0.05). For the dorsolateral frontal cortex, p-tau density was measured at the depth of the cortical sulcus (defined as the bottom third of two connecting gyri) and at the gryal crest (defined as the top third of two connecting gyri). For quantitative hippocampal subfield analysis, CA2 and CA3 were combined into one field denoted as CA2/3. Y-axis values are positive pixels (mm²) and are on a logarithmic scale.