Figure 10.

Effectiveness of using regression ERPs (rERPs) to account separately for stimulus and response processes that overlap in the single-trial EEG data. A) The “raw” response-locked ERP-image for all congruent and incongruent hit trials is plotted, sorted by response time. Sigmoidal dashed line and vertical solid line reflect stimulus and response latencies, respectively. B) Pseudo-data for rERP estimated trials was constructed by: 1) substituting each subject’s response-locked rERP waveform (aligned to the button-press) in place of his or her trial data, and then 2) superimposing that subject’s stimulus-locked rERP, shifted backwards in time with respect to stimulus onset. C) The ERP image from subtracting image (B) from (A) is plotted to demonstrate that rERP is effective at removing stimulus and response potentials from trial EEG, as reflected by little consistencies in blue or red hues across trials. D) Grand average residual potentials after “EEG − rERP” (described above) and E) “EEG − ERP” (similar to above description, but substituting standard ERPs for overlap-corrected rERPs) illustrate superiority of the rERP approach to standard ERPs in modeling and accounting for trial evoked potentials. Note that the overlap-corrected rERP approach better accounts for overlapping stimulus and response potentials because the residual averaged ERP in (D) contains virtually no non-zero potentials while the same is not the case in (E).