with conflict monitoring (anterior cingulate cortex; Lavric et al., 2004). The no-go P3 is also increased for demands of response inhibition, but peaks between 300 and 500 ms post-stimulus, and has a more central or anterior distribution compared to the parietal P3 response related to response commission (Pfefferbaum et al., 1985; Kopp et al., 1996; Fallgatter et al., 1997). Reliable no-go N2 and no-go P3 components have also been elicited by the suppression of covert responses (e.g., counting some stimuli but not counting others; Pfefferbaum, 1985), indicating that the effects are not solely due to overlapping motor potentials or the withholding of a covert motor response. While the no-go N2 has generally been associated with response inhibition, the findings for the no-go P3 have been a matter of debate: despite work suggesting the no-go N2 and no-go P3 having similar neural sources identified through source localization (Bokura et al., 2001), several studies have found no effect of response type on the P3 when go and no-go trials are equiprobable (Lavric et al., 2004; Falkenstein et al., 1999), and as the P3 response is notoriously sensitive to stimulus frequency (Yamaguchi and Knight, 1991), it is possible that the experimental effects are
