We were able to discriminate target vs. standard EEG trials with highly significant accuracy (Figure 3). We surpassed the corrected p = 0.01 value (Az = 0.66) for all consecutive stimulus-locked training windows from 150–750 ms and for all analyzed response-locked windows centered at −250 ms or later. Maximum discrimination of Az = 0.86 ± 0.04 was reached at 325 ms for the stimulus-locked classification, with a broad temporal peak. Response-locked classification yielded even higher Az values, with a double peak shortly after reaction time. A maximum Az of 0.93 ± 0.04 was reached at 25 ms following RT, and 0.91 ± 0.07 Az was reached at 150 ms. The window ranges exceeding 0.75 mean Az (and thus subsequently included in the EEG-based fMRI analysis) were 175 to 600 ms for stimulus-locked and −175 to 375 ms for response-locked discrimination.
