PROBE P3 AND BLINKS - 2 MEASURES OF AFFECTIVE STARTLE MODULATION

Two concurrent measures of the evoked startle response, the elicited b link reflex and the event-related potential, were measured while indiv iduals viewed pictures that varied in pleasure and arousal. Replicatin g previous findings, the blink response was modulated by picture pleas antness, with larger reflexes elicited in the context of viewing unple asant versus pleasant pictures. However, the probe P3 was primarily mo dulated by picture arousal, with smaller P3 responses elicited when vi ewing affective (pleasant or unpleasant) than when viewing neutral pic tures. Both modulatory effects were sustained for probes presented in a subsequent picture imagery period. These data suggest that two measu rable responses to the same startle probe are differentially modified by emotional context, with blink magnitude varying with pleasure and p robe P3 varying with stimulus arousal.