The effects of an emotional stimulus prepulse on probe startle respons
e were examined here. Pleasant, neutral, and unpleasant pictures were
viewed for 6 s, and an acoustic startle probe was presented either 300
, 800, 1,300, or 3,800 ms after slide onset, or 300 or 3,800 ms after
slide offset. Blink magnitude and onset latency demonstrated (a) an ea
rly (prepulse) inhibition effect in which reflexes elicited immediatel
y after slide onset were smaller than reflexes elicited later in the v
iewing interval, and (b) affective modulation, in which unpleasant sti
muli prompted larger reflexes than pleasant. Interactive effects of pr
obe time and picture valence indicated attention/arousal effects early
and pleasantness effects late in the picture interval. Effects of bot
h attention and emotion can be simultaneously measured using this star
tle-probe paradigm, encouraging its use in both basic and clinical con
texts.