Personality, event-related potential (ERP) and heart rate (HR) in emotional word processing

Gray's theory asserts that anxiety is associated with high sensitivity to signals of punishment and impulsivity with high sensitivity to signals of reward. These hypotheses were tested by engaging subjects in four emotional-word recognition tasks using a visual oddball paradigm. Each task was formed by combining standard and target stimuli with respect to emotional valence of the words (positive-standard/positive-target, positive-standard/negative-target, negative-standard/positive-target, negative-standard/negative-target). For target words the following measures were obtained: (1) peak amplitude and latency of the P3 ERP component; (2) heart rate change; (3) reaction time; (4) emotional feeling ratings. Orthogonal personality dimensions of impulsivity and anxiety were derived from a mutual analysis of popular personality and temperamental scales. The results showed higher P3 peaks over parietal and occipital leads when target words had an opposite emotional valence to standard ones. More pronounced HR decelerations were also obtained for these conditions. Across frontal and temporal recording sites, P3 amplitude was larger in high-anxiety subjects than in low-anxiety ones for unpleasant words, suggesting higher sensitivity to negative emotions. High-anxiety subjects also displayed higher emotional ratings and more pronounced HR decelerations to unpleasant targets. High impulsivity subjects, compared to low impulsivity ones, showed smaller P3 peaks for negative valenced targets mainly over parietal and occipital cortical regions and longer P3 latencies across all recording sites. The expected amplification of the response to negative emotion in the high anxiety group was confirmed, but the corresponding prediction for impulsiveness and positive emotion was not supported. These findings, however, appear in line with the “joint subsystems” hypothesis (Corr, 2002) that predicts a lower level of sensitivity to signals of punishment in high impulsivity subjects.