Motivated and controlled attention to emotion: time-course of the late positive potential.Clin Neurophysiol. 2009 Mar; 120(3):505-10.CN
The present study examined the time-course of automatic and controlled modulation of the late positive potential (LPP) during emotional picture viewing.
Participants (N=32) viewed neutral and unpleasant stimuli for 6000 ms; at 3000 ms, one of two tones signaled participants to attend either to a more or less arousing portion of the picture. The time-course of the LPP was examined both during the passive viewing and directed attention portions of the trial using the method proposed by Guthrie and Buchwald [Guthrie D, Buchwald JS. Significance testing of difference potentials. Psychophysiology 1991;28(2):240-4].
During passive viewing, the LPP became reliably larger following the presentation of unpleasant pictures from 160 ms onward; the magnitude of the LPP became reliably smaller beginning 620 ms after participants were instructed to attend to the less arousing aspects of unpleasant pictures - and this difference was maintained throughout the duration of the trial.
The LPP reflects relatively automatic attention to emotional visual stimuli, but is also sensitive to manipulations of directed attention toward arousing versus neutral aspects of such stimuli.
These results shed further light on the time-course of emotional and cognitive modulation of the LPP, and suggest that the LPP reflects the relatively rapid and dynamic allocation of increased attention to emotional stimuli.