Figure 1.

Design and behavioral results. (A) Design of the cued go/nogo task. On the upper row a block is illustrated where subjects had to refrain from pressing the button when the target (triangle) appeared on the right side of the screen. Similarly, in the block displayed in the lower row a stop was required when the target appeared on the left side. In the Maybe Stop (MS) condition (dark gray) the subject was told by the cue (square, circle) that he might have had to stop later on, while in the Certain Go (CG) condition (light gray) he was informed by the cue that he always could press the button when the target appeared later on. (B) Behavioral results showing mean reaction times in No Stop-, Frequent Go- and Rare Go-trials. As error bars the standard errors of the mean (SEM) are displayed. Significant effects are stressed with asterisks.