Effects of a startle stimulus on response speed and inhibition in a go/no-go task

Two studies examined the interaction of an acoustic startle stimulus and visual go/no-go task stimuli on startle reactivity and task performance. In the first study, an acoustic stimulus (50ms, 100dB noise) was presented alone or with a green (go) or red (no-go) circle; in the second study, a prepulse (50ms, 75dB noise) was presented alone or 120ms before the startle stimulus or circle. The startle stimulus speeded responses to the go stimuli and increased the covert false alarm rate in the no-go condition (measured by EMG activity in the hand), although very few overt errors were made in the no-go condition. Startle response magnitude was increased by a circle but decreased by a prepulse. The speeding of go responses caused by a startle stimulus was attenuated by the occurrence of a startle response, suggesting that an intense accessory stimulus can facilitate responding to an imperative stimulus, and that the startle response to that intense stimulus can interfere with that facilitation.