amplitude would facilitate the interpretation of the components and their correlation with other factors (due to data reduction), and 2) the topography of ORN and ORP components suggested 3 major regions, viz., frontal, central, and parietal areas. The factors were extracted using principal component analysis (PCA), and varimax rotation with Kaiser normalization was performed. The optimal number of factors was determined based on the shape of the scree plots (i.e. components lie on the steep slope). However, factor analysis was not done on BIS scores as they were already categorized into three distinct factors (Barratt, 1985; Patton et al., 1995).
