Discordant effects of weak prestimulation on magnitude and latency of the reflex blink

Abstract

In three experiments, the human blink response to 50-msec 105-dB white noise was markedly reduced by prior stimulation with weak tones, either 20 msec long or coextensive with lead intervals of 30 to 240 msec. Although the inhibitory effect was greater with a 70-dB than with a 60-dB lead tone, it was not affected by increasing the lead-tone duration beyond 20 msec. At lead intervals of 30 and 60 msec, the latency of blink onset was also reduced by prestimulation, and this effect was greater with the longer lead tones. Neither effect was an artifact of responding to the lead tone itself. The simultaneous occurrence of an inhibitory change in magnitude and a facilitatory change in latency, and the differential influence of lead stimulus duration, suggest that the magnitude and latency modifications involve different neural mechanisms with different time constants. © 1977, Psychonomic Society, Inc.. All rights reserved.