Figure 2.

Time-domain and time-frequency representations of FRN and P300 differences for Loss versus Gain trials. Top line plot: Average response-locked ERP waveforms at FCz, depicting the expected negativity for Loss versus Gain trials associated with the FRN as well as the time-domain P300. Waveform plots, second level: Average time-domain ERP activity for Loss and Gain trials separately, frequency-filtered to capture activity in the theta (3–9 Hz) range corresponding to FRN response (FCz; left plot) and activity in the delta (3 Hz) range corresponding to the P300 response (Cz; right plot). These plots demonstrate that theta and delta show opposing effects for loss compared with gain feedback such that theta is stronger for loss versus gain whereas delta is stronger for gain versus loss. Color surface plots, third level: Loss-Gain difference scores for the principal component loadings on theta-FRN (left map) and delta-P300 (right map), derived from a TF decomposition of average EEG activity following Loss and Gain trials. Topographical maps, bottom level: Scalp topography distributions for the mean condition difference (Loss-Gain) of TF-PCA loadings for theta-FRN (left map) and delta-P300 (right map). Similar to the time-domain FRN and P300, electrodes FCz and Cz, respectively, were most proximal topographically to the maximum theta and delta Gain-Loss differences. However, compared to the highly correlated time-domain FRN and P300, the Gain-Loss difference scores for theta and delta were uncorrelated. The implication is that these theta and delta TF measures index separate processes that differentiate between Loss and Gain feedback outcomes.