Figure 5.

A, Grand averages of stop stimulus-locked ERPs at midline electrodes in the Val (dashed lines) and Met groups (solid lines) for successfully inhibited trials. The P3a is indicated with an arrow. B, For illustration of the N2 effect, ERPs in inhibited trials are shown for the two groups at the Fz electrode with a bandpass filter of 2–12 Hz. C, Depicted are the isovoltage maps of the amplitude difference between Val/Val and Met/Met for the stop N2 (200–220 ms; left) and the P3a (300–350 ms; right). As the groups differed in the preceding positivity of the N2, we show for illustration the amplitude difference relative to the baseline from 100 to 200 ms. Maximum and minimum values are for the N2 are −1.2 and 0.2 μV, and for the P3a are −1.5 and 5.5 μV. D, Mean peak-to-peak amplitudes for the N2 at Fz for the four different groups in inhibited trials (with their respective SEs). E, Mean amplitudes for the P3a in the four different groups in inhibited trials (300–350 ms) with their respective SE.