The distribution of PCA Scores across each of the 5 days of Pavlovian training, using the formula given in Table 1.

<p>The number of rats are binned according to their PCA Scores, which ranges from +1 to −1, with 0.1 bin sizes. The PCA Scores range from +1 to −1. Thus, the vertical axis shows the number of rats in each bin, and the horizontal axis the PCA Score. Note that PCA Score reveals two subpopulations of animals by Days 4 and 5 of training.