Figure 11.

Error-related effects in pMFC trial residuals after subtraction of stimulus- or response-locked rERPs. A) Grand averages (upper) and ERP images (lower) reflecting stimulus- (left) and response-locked (right) trials that were constructed by subtracting the stimulus-locked rERP from “raw” trial potentials; 3,874 trials were drawn from only those participants who possessed at least six error trials and overlap-corrected rERPs (see Method section). Here, because stimulus-locked rERPs were removed from trial potentials, non-zero potentials in stimulus-locked residuals reflect confounding from response-locked processes. Horizontal bars plotted above waveforms indicate regions where logistic regression showed trial potentials were significantly related to the occurrence of an error (p_FDR < .01 for more than 50 consecutive ms) for congruent (light shaded bars) and incongruent trials (dark shaded bars); navy blue dotted boxes highlight Frontocentral P3 and Pre-Movement Positivity (PMP) windows in stimulus- and response-locked epochs, respectively. B) Trials constructed by subtracting response-locked rERPs from trial potentials; here, non-zero potentials in response-locked residuals reflect confounding from stimulus-locked processes. Notably, voltage negativity in Frontocentral P3 and PMP windows was associated with errors only in trial residuals for which stimulus-locked rERPs were removed (A). Vertical and sigmoidal-vertical lines in (A) and (B) reflect stimulus (dashed) and response (solid) latencies, respectively. C) Odds ratios (ORs, circles) less than 1 reflect greater odds of an error given more negativity in Frontocentral P3 / PMP windows in “raw” EEG trials (top, no rERPs subtracted). Removing stimulus-locked rERPs from trial EEG (middle) strengthened associations between small Frontocentral P3 or PMP and errors, as indicated by comparatively smaller ORs and confidence intervals that do not contain ORs from raw EEG trials (p < .05, Incongruent P3 and PMP only). Removing response-locked rERPs (bottom) resulted in ORs that were greater than 1, suggesting that response-locked rERPs were responsible for prior associations between small single-trial Frontocentral P3 / PMP and errors.