artifacts and noise, on the basis of the signal-to-noise ratio (SNR) and the explained variance. The SNR, defined as the ratio between the maximum amplitude in the post-stimulus interval and the root mean square (RMS) in the pre-stimulus interval, was calculated on the rare event time-course. The IC variance was measured from the IC weights provided by the ICA decomposition [James and Hesse, 2005]. The ICs with SNR larger than 10 and explained variance larger than 1% were considered salient event-related patterns of brain activity, and therefore were selected for further analyses. Finally, the amplitudes associated with the selected ERP-IC time-courses were back-reconstructed by linear projection, using information from the ERP data.
