Figure 1.

Event-related potentials showing differential brain activity to S^Ds (targets) and S^Δs (standards) during a passive condition (in which participants were passively looking at the stimuli), a covert condition (in which participants were covertly counting S^Ds), and an overt condition (in which participants were pressing a button after S^Ds). Data were measured from electrode CP, a centro-parietal electrode located in the midline. Data reflect the grand average of 26 participants; for each participant there was a range of 40 to 80 trials in the S^D condition and 160 to 320 trials in the S^Δ condition. (Figure reproduced by permission of Elsevier, from Potts, 2004.)