Effect of negatively valenced words on deviant P3 during the three-stimulus oddball paradigm.

Attentional bias (sensitization) for negative information was estimated using event-related brain potentials (ERP). We used a three-stimulus visual oddball paradigm that comprised a small diamond standard stimulus (66.7%), a large diamond target stimulus (16.7%), and deviant word stimuli (16.7%) written in Kanji. Furthermore, half the deviant words were negative emotional words (e.g., destruction or scream) and the others half were neutral words (e.g., structure or range). Healthy participants (N = 26) were instructed to press a button after the target appeared while ignoring the other stimuli. EEG was recorded from Fz, Cz, and Pz sites and the average of EEG that time-locked to the onset of stimuli was calculated. Results indicated that the P3 amplitude for the target at Pz was the largest among the three sites, whereas the P3 amplitude for deviant words at Cz and Pz was larger than those at Fz. Furthermore, the P3 amplitudes for negative words increased in comparison to those for neutral words. These results suggest that increased amplitudes to word stimuli are regarded as deviant P3, and changes reflect passive attentional capture elicited by negative emotional information. Implications for using ERPs for estimating attentional bias to threat information are discussed.