The rank order of cases for NFT density in the EC was negatively correlated with the number of neurons (Spearman rank correlation test n = 17, Z = 3.40, p < 0.001). We also calculated the relationship between the rank order of NFT densities and the number of neurons in the AD group alone (n = 9, Z = −2.24,p = 0.02). The graph represents data from nine AD brains. In one case, the PHF-1 immunostaining for NFTs was not available.