artifact templates, including EKG and EOG recordings, simulated BCG, volume MRI and slice MRI artifacts. A specific IC was considered artifactual in case of rt > 0.2 for at least an EEG artifact template. With this procedure, from 8 to 14 artifactual ICs were typically detected, and subtracted from the EEG recordings using the weights provided by the ICA decomposition (Mantini et al., 2007a). The artifact-corrected EEG signals were averaged with respect to rare and frequent event instants (100 ms pre-stimulus and 600 ms post-stimulus time), in order to obtain ERPs. The resulting ERPs were used to calculate, for each electrode, an ERP signal-to-noise ratio (SNR), defined as the ratio between the maximum amplitude in the post-stimulus interval and the root mean square (RMS) in the prestimulus interval.
