A multi-process account of startle modulation during affective perception.

Modulation of the startle reflex by sensory, attentional, and emotional processes was explored by presenting acoustic startle probes at various delays following picture onset. Within 500 ms of onset, blinks were first greatly facilitated and then inhibited, indicating prepulse facilitation and prepulse inhibition that did not vary with affect. Attention allocation to the picture continued across the viewing interval and was most pronounced for emotional pictures, as determined by attenuation of the P3 component to the startle probe. Startle potentiation for unpleasant pictures occurred later in the viewing interval and was strongest for highly arousing pictures. Taken together, the startle reflex during picture viewing is modulated by sequential and sometimes concurrent processes of prepulse facilitation, prepulse inhibition, attentional inhibition, and affective modulation, with reflex magnitude reflecting the net effect of multiple processes.