First three principal components are depicted in 3D. The selection of first three principal components is decided by the Scree-plot (Figure 3G), and expressed for 208 normalized data (circles) in three-dimensional plot, (A). These transformed values are viewed by pairs in two-dimensional: First and second principal components (B), first and third principal components (C), and second and third components in (D). All zero origins are marked “⊗” for a reference point with the line axes.
Uragun and Rajan BMC Neuroscience 2013 14:114 doi:10.1186/1471-2202-14-114