Trials were presented in a pseudorandom sequence such that left and right trials were presented in roughly equal numbers. The time necessary to stop and redirect a motor action (SCRT) on STOP trials was computed using the difference between the average movement time on correct STOP and Go trials (11, 12, 24, 25, 40). While we recognize that there are multiple ways to estimate the timing necessary to inhibit a movement (42), we chose to use SCRT because we have access to STOP trial movement time distributions and we varied the STOP-signal delay systematically across sessions, making SSRT-mean and integration methods inappropriate for our dataset (1, 42).
