Figure 3.

Time-domain and time-frequency representations of FRN and P300 to Loss and Gain feedback, depicted separately for subgroups of high (N = 57) and low (N = 40) externalizing participants as defined by scores on a 100-item version of the Externalizing Inventory (Krueger, Markon, Patrick, Benning, & Kramer, 2007). High and low externalizing groups were formed by oversampling from the top and bottom 25% of scorers in an undergraduate screening pool. Waveform plot, top level: Average unfiltered ERP activity following Loss and Gain feedback for these high and low externalizing subgroups. Here, a broad amplitude reduction is evident for individuals in the high relative to those in the low externalizing group. In this unfiltered data, however, it is unclear whether this overall amplitude reduction reflects differences in theta-FRN or delta-P300. Waveform plots, second level: Average time-domain ERP activity following Loss and Gain feedback stimuli for these extreme subgroups, frequency-filtered (3^rd order Butterworth) to capture activity in the theta (3–9 Hz bandpass) range corresponding to FRN response (left plot) and activity in the delta (3 Hz lowpass) range corresponding to the P300 response (right plot). Color surface plots, third level: Time-frequency representation of TF-PCA principal component scores reflecting the theta-FRN and delta-P300 activity from the ERP signal, derived from a TF decomposition of average EEG activity following Loss and Gain trials. Statistical maps, bottom level: Scalp topography distributions, for the overall study sample (N = 149) that included these extreme subgroups, of p-values from correlations between externalizing scores and scores on the theta-FRN and delta-P300 TF-PCA components for: (1) all trials combined, (2) Gain trials, (3) Loss trials, and (4) Gain-Loss difference scores. These topographic statistical maps demonstrate that the association between externalizing and theta-FRN is pervasively nonsignificant, whereas the delta-P300 activity is significantly reduced for high externalizing individuals for the conditions reported, in particular when considering the average response or Loss and Gain trials separately. Thus, the reduced EEG activity in the unfiltered time-domain waveform at the top is attributable to reductions in the delta but not the theta frequency band.