The grand mean forward models displayed an early frontal positivity that was strongest at the 250 ms stimulus-locked window. They also revealed a central negativity around 325 ms, which occurred prior to behavioral responses and corresponded to the middle of the broad stimulus-locked discrimination peak. A posterior positivity first appeared near the RT and slowly became more centrally distributed, reaching its highest strength late in the trial. The progression of these discriminating components was consistent with the visual target detection results ofGerson et al. (2005). We show EEG topographies alongside their corresponding BOLD activations in Figures 4, 5, and 6.
