The Effect of Signalling Upon Control of an Aversive Stimulus

Abstract

When an aversive stimulus (S2) follows a weak neutral stimulus (S1), the responses to S2 are modified. Compared with an S2-alone control, facilitation occurs in the long-ISI (e.g., 8 s) condition, while inhibition occurs in the short-ISI (e.g.,. 5 s). The Si employed in this kind of study can have the three properties of time, warning, and physical stimulation as a signal. In this study, the relations between response modifications and SI properties were investigated, using the response measures of the eyeblink reflex and subjective aversiveness ratings.In addition to demonstrating the importance of the ISI variable, the results indicated that in the eyeblink reflex, the SI with only a physical stimulation property was necessary for facilitation, while the Si with at least time and physical stimulation properties was necessary for inhibition, and in the aversiveness ratings, the S1 with at least a physical stimulation property was necessary for inhibition, while no facilitation was found whatever property Si had.