Fig. 9

Multivariate principal component analysis (PCA). To understand the relationship of behavioral outcome and innate immune cell responses at 42 days after TBI, PCA was used. This analysis yielded five dimensional PC-loading patterns accounting for 80.55 % of total variance (details in Additional file 1: Figure S1). a Significant loading on PC1 indicated that more errors on the beam-walking tasks were associated with the numbers of peripheral inflammatory immune cells in the brain and (less so) with increased pro-inflammatory monocytes in the blood. Bilateral paw placement, a measure of recovery of cortical function, was inversely correlated between individual variables and PC1. Red arrow indicates a positive relationship, while blue arrow indicates negative relationship. PCs 2–5 also showed associations between behavioral recoveries and inflammatory markers (see Additional file 1: Figure S1). b Post hoc analysis of the main effects on PC1 (27.1 % of total variance) indicated that there is a significant effect of injury (F _1,39 = 21.412, p = 0.000, η ² = 0.380, power = 0.994) and of EVT901 treatment (F _1,39 = 4.435, p = 0.042, η ² = 0.112, power = 0.535)