Event-related potentials (ERPs) elicited in target-and-probe (TP) and target-only (T) conditions in experiment 1. A, top: group-mean ERPs at a right frontotemporal electrode (FT10) and a midline parietal electrode (Pz). Gray shading represents the time intervals of the difference between TP and T conditions to reach significance. Bottom, topographies of ERP difference during the time intervals. B, left: difference in source activity between TP and T conditions. Right, time series of difference in source activity, where red shading represents time intervals of the difference between TP and T to reach significance. Sag, sagittal; Cor, coronal; Tra, transverse; A, anterior; P, posterior; R, right; L, left.