Experimental design. A, The temporal evolution is indicated vertically. At the outset of the trial, an icon appeared at the top of the screen and descended its length in ∼12 s. The participant controlled the turtle at the bottom, which could only move horizontally. During the indication period, the turtle icon either turned red (if caught by the threat) or green (if it caught the reward) or did not change color (if the subject escaped the threat or missed the reward). The inset shows the icons used as a function of experimental condition, and the icon controlled by the participant (“player”). B, Schematic responses illustrating our primary hypothesis: potential imminence-related responses. Here, responses assumed a brief initial transient response followed by imminence-related responses for different threat and reward levels. The final simulated response was obtained by summing transient and sustained hypothesized components. The gray zone indicates the temporal window considered for analysis at trial end. The dashed line in the top row represents a canonical hemodynamic response filter convolved with a boxcar function lasting for the duration of the stimulus, as was assumed in most prior studies, for comparison.