The current study also permits some inferences to be made about the observed theta-FRN activity relative to the ERN. First, the dissociation between the FRN and ERN in relation to externalizing proneness supports the view that these are not identical processes, a point that has been debated recently in the field. Furthermore, insofar as both the ERN and FRN are thought to have similar primary sources in the ACC (e.g. Dehaene et al., 1994; Holroyd et al., 2004), the current findings suggest that the self-monitoring deficits associated with externalizing proneness do not reflect a simple global impairment in the functioning of the anterior cingulate cortex (ACC). At the same time, to the extent that the ERN and FRN are presumed to reflect a highly similar cognitive-monitoring process, it is surprising that we did not find a negative relationship between theta-FRN amplitude and externalizing proneness similar to that which has been reported for the ERN.
