The BIS and TRB variables were compared across groups using t-tests. Based on the analyses done in our previous study (Kamarajan et al., 2009), the correlations between ERP variables and Behavioral measures were analyzed in a 2-step procedure: 1) Factor analysis was performed in order to reduce the ERP variables (N = 144) as well as the TRB variables (N = 24) into a few specific factors; and 2) Pearson (bivariate) correlations were performed to analyze the relationship between behavioral factors and ERP factors. ERP variables for the factor analysis comprised 9 electrodes (F3, FZ, F4, C3, CZ, C4, P3, PZ, P4), 4 outcomes (+50, +10, −50, −10), 2 components (ORN, ORP), and 2 measures (amplitude, latency). For factor analysis, only 9 electrodes were selected for two reasons: 1) we expected that factors comprising fewer but representative electrodes of maximum 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
