Prepulse inhibition of the acoustic startle reflex: Comparing low and high trait anxious individuals

Sturm, Krista (2014) Prepulse inhibition of the acoustic startle reflex: Comparing low and high trait anxious individuals. Undergraduate thesis, under the direction of Dwight Waddell from Electrical Engineering, The University of Mississippi.

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Abstract

This investigation examined whether prepulse inhibition of the acoustic startle reflex was impaired among individuals with high trait anxiety compared to controls. PPI has traditionally been theorized to be a psychophysiological index of information processing and sensorimotor gating, and is now being used to help identify various psychological disorders. Although results of existing research on reduced PPI across the anxiety spectrum are equivocal, previous findings indicate that highly anxious (HA) participants exhibit significantly reduced PPI at lead intervals of 60 ms relative to low anxious (LA) controls. This study paired a 70 dB (A) white noise prepulse stimulus with a 100 dB (A) white noise startling stimulus at a 60 msec discrete lead interval. The results showed a higher baseline startle response and a trend toward increased response probability among the HA subgroup compared to controls. Due to a large number of nonresponse trials, analysis of PPI between groups could not be performed, but the data that was obtained revealed a 2.2% reduction in PPI among highly anxious participants. The current results highlight the potential for PPI to index sensorimotor gating deficits among anxious populations.

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