The modulation of the Ne-like wave on correct responses foreshadows errors

In reaction time (RT) tasks, event-related potentials (ERPs) reveal a response-locked negative wave when subjects commit errors. This wave. termed error negativity (Ne) or error-related negativity (ERN), is thought to index response-monitoring processes. With conventional monopolar recordings, this negativity is hardly seen on correct responses, likely overlapped by a large positive wave. Indeed, after Laplacian transformation (a spatial high-pass filter), a small Ne-like wave is unmasked. Recently, it has been shown that the positivity on monopolar recordings was larger for correct responses preceding an error than for correct responses preceding a correct trial. After Laplacian transformation, it appears that this effect is due, at least in part, to a decrease of the Ne-like wave on correct responses preceding an error. This result indicates that, as the Ne on errors, the Ne-like wave on correct responses is sensitive to performance and hence is likely related to response-monitoring processes. (C) 2004 Elsevier Ireland Ltd. All rights reserved.