Auditory-evoked EEG oscillations associated with prepulse inhibition (PPI) of auditory startle reflex in healthy humans.

The aim of the current study was to investigate the prepulse inhibition (PPI) of auditory-evoked delta, alpha, and gamma oscillations. Concurrent EEG and auditory startle reflex were recorded from 15 healthy participants during Pulse-Alone and Prepulse+Pulse trials with 60, 120, and 240 ms prepulse-pulse intervals. A significant PPI of the startle reflex on all Prepulse+Pulse trials was associated with a significant PPI of alpha oscillations at central and temporal locations and of gamma oscillations at frontal, central, and temporal locations on some Prepulse+Pulse trials. PPI of delta oscillations was not observed. These results confirm our recent finding stating that PPI functions as a sensory-motor as well as a sensory-cognitive gating mechanism because alpha and gamma oscillations mediate cognitive processes.