A possibility of error‐related processing contamination in the No‐go N2: The effect of partial‐error trials on response inhibition processing

This study investigated whether error‐related negativity (ERN) elicited by partial errors and No‐go N2 represent distinct or similar components. We also investigated whether the error positivity (Pe) and No‐go P3 represent distinct or similar components. Partial‐error trials are behaviourally classified as correct trials but preceded by covert muscular activities. Recent studies have reported that analysing partial‐error trials is useful for investigating the functional roles of ERN and No‐go N2. In this study, 23 participants performed a Go/No‐go flanker task. They performed nine blocks of 60 trials each. Stimulus‐locked event‐related potentials (ERPs) were averaged separately for Go‐congruent pure‐correct trials, Go‐incongruent pure‐correct trials and No‐go pure‐correct trials. In addition, we compared the stimulus‐locked ERPs among No‐go pure‐correct trials, No‐go partial‐error trials, Go‐incongruent pure‐correct trials and Go‐incongruent partial‐error trials. Electromyogram (EMG)‐locked ERPs were averaged separately for correct trials, overt errors in No‐go trials, partial errors in No‐go trials, overt errors in incongruent trials and partial errors in incongruent trials. N2 was remarkably larger in No‐go partial‐error trials than in No‐go pure‐correct trials. Consistent with previous findings, the No‐go partial‐error N2 might reflect error‐related processing. P3 amplitudes were larger in the No‐go trials than in both the Go‐congruent and Go‐incongruent trials. These results suggest that the No‐go P3, but not the No‐go N2, might reflect inhibition of overt movement. The present findings provide further evidence that the previously reported increase in No‐go N2 may be due to an overlap of the ERN elicited by partial errors.