al., 1999; Bernat et al., 2007; Karakas et al., 2000). Our group and others have shown that parietal evoked delta underlying the time-domain P3 peak explains a large portion of the variance in P3AR’s association with externalizing psychopathology (Gilmore et al., 2010a; Jones et al., 2006; Rangaswamy et al., 2007). It is less clear how P3-related theta might contribute to this group difference. One study showed that theta-focused principal components derived from evoked ERPs are smaller for externalizing-relative to control-subjects (Yoon et al., 2013); however, others suggest that theta’s contribution to P3 is more complex than what can be observed in the evoked ERP (Andrew and Fein, 2010; Jones et al., 2006; Rangaswamy et al., 2007). Because the vast majority of studies investigating P3AR focus exclusively on evoked P3, the effect is typically interpreted to indicate that externalizing individuals respond with smaller-voltage P3s to the stimulus on each trial.
