Blink reflex magnitude during the foreperiod of a warned reaction time task: effects of precueing.

Abstract

ABSTRACTIn a warned reaction time task blink reflexes were evoked electrically at different points in time during a 3‐s foreperiod between the warning signal (WS) and the response signal (RS;. Two groups of 16 well‐trained right‐handed subjects participated. One group was informed by the warning signal as to whether or not a voluntary blink response was to be given following the response signal. For the other group of subjects, response‐relevant information was delivered by the response signal. Reaction times were shorter when subjects were precued by the warning signal, which indicates a more efficient preparation in this condition. In the blink reflex an early ipsilateral component (R1) and a late bilateral component (R2) could be distinguished. Within 300 ms after the warning signal, an increase in R1 was seen which was more pronounced when the warning signal precued the required response. R2 was inhibited shortly after the warning signal. At the end of the foreperiod R1 increased more and R2 was more inhibited the higher the response certainty. The general conclusion is that the presentation of a warning stimulus has a facilitatory effect on R1 and an inhibitory effect on R2. A warning stimulus with more information results in an extra increase in R1 magnitude only, while preparation for a response is seen in both R1 and R2 magnitudes.