Fig. 1.
Paradigm. (A) During Stop-relevant (SR) blocks, a choice-reaction stimulus (green German traffic-light symbol oriented to the left or right) was either presented during the entire stimulus duration of 800 ms (Go-trial, GT_SR) or substituted until the end of the stimulus duration by a red Stop-sign (Stop-trial, ST_SR) after a certain variable SOA that was set trial-to-trial by a tracking algorithm. This Stop-sign indicated to withhold the triggered response, thus leading to either a successful (SST_SR) or an unsuccessful Stop-trial (UST_SR). (B) In Stop-irrelevant (SI) blocks the visual stimulation was identical, but the Stop-signs were irrelevant, i.e. responses were required both to Go-trials (GT_SI) and “Stop”-trials (ST_SI).