Selective and nonselective attention effects on prepulse inhibition of startle: a comparison of task and no-task protocols.

The effects of selective and nonselective attentional processes on prepulse inhibition (PPI) of the acoustic startle response were examined by assessing PPI under intermixed task and no-task conditions. Results for the task condition revealed that greater PPI was produced by an attended than an ignored prepulse at a lead interval of 120 ms (marginally significant in the early trial block and significant in the late trial block), indicating an effect of selective attention at this lead interval. Comparisons between the task and no-task conditions revealed significantly greater PPI in the task than no-task condition at a 60-ms lead interval, during early and late trial blocks, indicating a nonselective attention effect at this lead interval. Overall, these results suggest that PPI is sensitive to selective and nonselective attentional influences and indicate that task and no-task PPI protocols reveal unique aspects of sensorimotor gating ability.