Prepulse Inhibition of the Startle Reflex: Preliminary Study of the Effects of a Low Dose of Alcohol in Humans

Abstract

The present study was designed to examine the effects of a low dose of alcohol on prepulse inhibition (PPI) of the startle response and self-report measures of affect. Eighteen subjects participated in a counterbalanced repeated-measures design in which they received a beverage with alcohol during one session and a nonalcohol beverage during a different experimental session. The startle response was probed in two separate 10-min blocks immediately after consumption of the alcohol. Although alcohol significantly suppressed the startle response in general, it did not do so to an extent that compromised detection of PPI. The effects of alcohol on PPI were primarily evident in the first block and were dependent on baseline levels of PPI, such that alcohol resulted in a reduction of PPI in subjects who demonstrated low PPI at baseline and an increase in PPI for subjects with high PPI at baseline. Alcohol also significantly increased self-reported stimulation during the first block and increased negative affect during the second block. These findings suggest that baseline PPI may reflect an important individual difference that is predictive of the direction and magnitude of alcohol-induced changes in sensorimotor gating.