A relationship between inhibition of the acoustic startle response and the protection of prepulse processing

Abstract

The relationship between prepulse inhibition of the startle eyeblink reflex and the processing of the prepulse was tested by measuring both the startle eyeblink response and the accuracy of identification of the prepulse in college students. In Experiment 1 (N = 26), startle stimuli were 100- dB(A), 50-msec-duration noise pulses, preceded on some trials by low- or high-frequency 65-dB(A) tone prepulses at stimulus onset asynchronies (SOAs) of 30-800 msec; in Experiment 2 (N = 21), prepulses were 50- or 200-Hz vibrotactile pulses to the hand, at SOAs of 50-800 msec. Average prepulse identification accuracy was significantly higher on trials during which startle magnitude was inhibited than on trials during which startle magnitude was not inhibited, at all SOAs. This simultaneous occurrence of prepulse inhibition and higher prepulse identification accuracy shows that the inhibition of the startle response by the prepulse coexists with a decrease in degree to which the startle stimulus (or response) interrupts the preattentive processing of the prepulse.