Abstract
Using a CS1-Shock1-CS2-Shock2 paradigm, the attenuation of conditioned suppression during CS2 paired with Shock2 by immediately preceding CS1 + Shock1 or CS1-Alone was studied in four groups of rats in which the Shock1 intensity was varied across groups. Compared with the None condition, in which no stimuli preceded CS2, both CS1 + Shock1 and CS1-Alone attenuated conditioned suppression, the amount of attenuation being greater in the former than in the latter. The dis-suppression ratio, or the relative amount of suppression of CS1 + Shock1 and CS1-Alone conditions to the respective None condition of each group, indicated that the ratio increased as a function of Shock1 intensity in both conditinos. Present results are consistent with the opponent-process theory of emotion.
