Figure 1.

Task design. Subjects performed a response-conflict task under two contexts, safe and threat. During the threat condition (shown here), a cue stimulus (diamond) signaled that a mild electric shock could occur during the delay period following cue offset and prior to the target display. Participants were instructed about the meaning of the cue stimuli prior to task execution. During the target phase, participants were asked to indicate whether the picture contained a house or a building, while ignoring the superimposed word. During the safe condition (not shown), the trial structure was identical, except for the shape of the cue stimulus (rectangle) and the fact that shocks were never administered.