of response conflict monitoring on correct trials that arises from competition between execution and inhibition of a single response (Botvinick et al., 2001; Braver et al., 2001; Nieuwenhuis et al., 2003). Although few studies have interpreted the NoGo N2 “effect” as inhibitory in an equal probability paradigm (Jodo and Kayama, 1992; Lavric et al., 2004), there are a growing number of studies suggesting that it can be better explained by the conflict monitoring hypothesis (see Botvinick et al., 2001; Donkers and van Boxtel, 2004; Nieuwenhuis et al., 2003). Stimulus modality and difficulty level of discriminating between competing stimuli also have their influence on Go/NoGo N2 modulation and have been interpreted by the conflict monitoring hypothesis (Nieuwenhuis et al., 2004). Further, in a study that used response priming and evaluation of the lateralized readiness potential (LRP) to assess the effects of the motor response related contribution to brain electrical potentials, Bruin et al. (2001) concluded that P3, but not N2, is associated with response inhibition, and speculated that the traditional Go/NoGo N2 “effect” should be explained in terms of response activation instead of response inhibition. Additionally, in a review of studies that examined N2, Tucker et al. (2003) have interpreted that
