Modification of the electrically elicited eyeblink by acoustic, visual, and vibrotactile pulses

Abstract

The purpose of the present research was to investigate the cross-modal integration of sensory information in the blink reflex circuit. In three experiments, the eyeblink reflex was elicited by an electrical pulse to the forehead in college students. Weak pulses were acoustic in Experiment 1 (N = 28), visual in Experiment 2 (N = 17), and vibrotactile in Experiment 3 (N = 17). The R2 component of the electrically elicited eyeblink reflex was facilitated by weak acoustic pulses that were presented at the same time as or shortly after the electrical stimulus. A weak visual pulse also facilitated the blink reflex, but only when visual pulse onset preceded or occurred simultaneously with the electrical stimulus. Vibrotactile pulses presented to the hand did not cause facilitation at any interval. Weak pulses in all three sensory modalities presented before the blink-eliciting stimulus were able to inhibit the eye-blink reflex. These results suggest that the temporal summation that leads to facilitation of the blink response by weak stimuli occurs at a common location at which electrical, acoustic, and visual, but not vibrotactile, information converges. These data also show that facilitation and inhibition of the blink response are based on different underlying mechanisms.