- This folder contains all statistic files for the source estimations. First, there are the source models for each time window (e.g. stat 66 148.m), which as a results stores an SPM file with the respective beta information in separate folders (e.g. 66 148). The additionally calculated contrast for each condition, which can be found in each folder as well are explained in the contrasts_spm_interaction.m file. - Background: Source reconstruction of the generators of significant ERP differences were computed and statistically assessed with SPM12 for EEG (Litvak et al., 2011). First, a realistic boundary element head model (BEM) was derived from SPM’s template head model based on the Montreal Neurological Institute (MNI) brain. Electrode positions were then transformed to match the template head, which is thought to generate reasonable results even when an individual’s head differs from the template. Average electrode positions as provided by BioSemi were co-registered with the cortical mesh template for source reconstruction. This cortical mesh was used to calculate the forward solution. The inverse solution was calculated from 0 to 1,000 ms after word onset. Group inversion (Litvak & Friston, 2008) were computed, and the multiple sparse priors algorithm implemented in SPM12 was applied. This method allows activated sources to vary in the degree of activity but restricts the activated sources to be the same in all participants (Litvak & Friston, 2008). This has been found to result in more robust source estimations than does single-subject matrix inversion (Litvak & Friston, 2008). - Statistical analyses in source space were performed for significant scalp effects by applying the same time window as in scalp space (see main text). 3D reconstructions were generated as NIFTI images (voxel size = 2mm*2mm*2mm) and smoothed using an 8mm full-width half-maximum filter. Statistical comparisons reported for source space were restricted to time windows that revealed significant differences on the scalp. Similar to previous studies (Campo et al., 2013), we described statistical differences in source activity of voxels differing at least at an uncorrected threshold of p < .005 and a minimum of 15 significant voxels per cluster. In addition, results using family-wise error (FWE) corrected threshold of p < .05 and a minimum of 15 significant voxels per cluster are reported in all tables. The identification of activated brain regions was performed using the LONI atlas (Shattuck et al., 2008).