The eLORETA is a signal processing software package designed for localizing the neuronal electrical activity in the brain, and also involves several methods to analyze EEG source data (current density) in 3-dimensional neuroanatomical space with 6239 voxels at 5-mm3 spatial resolution [42]. The eLORETA algorithm is an inverse solution for the scalp recorded EEG signals, using weighted minimum norm inverse solution [42]. The localization accuracy with regard to brain sources of the scalp EEG signals was achieved using specific weights in the eLORETA algorithm [83]. The lead field, which determines how the electrical activity recorded at scalp electrodes is reflective of the actual sources in the brain [84], was derived using a realistic volume conductor head model [85] based on the standardized MRI brain atlas (template) from the Montreal Neurologic Institute (MNI152) [86]. The eLORETA algorithm estimates the neuronal electrical activity from the EEG scalp measurements using the lead field and head model, using a three-dimensional solution space restricted to cortical gray matter and electrode coordinates [87]. At each voxel in the cortical grey matter, a 3-component vector time series
