Research methodology

Our EEG research methodology consists of two main steps: (1) preprocessing and (2) analysis.

1. Given EEG recordings from a group of subjects:
1.1. Preprocessing, which has as goal the selection of high quality EEG for each subject.
1.2. Validation, if experimental ground truth is available, for each subject. Two examples:
1.2.a. If resting state eyes closed EEG is available, then EEG microstate scalp maps should qualitatively have the classic, empirically observed prototypical topographies (see e.g. https://doi.org/10.1016/j.neuroimage.2015.08.023).
1.2.b. If resting state eyes closed EEG is available, then the LORETA generators of oscillatory alpha activity should be located in posterior brain regions (see e.g. https://doi.org/10.1016/j.cnp.2017.09.002).
1.2.c. If event related potentials (ERP) are available, for instance, from visual stimulation, then the LORETA generators of the P100/N180 peaks should be located in the visual cortex. Response to auditory or somatosensory stimulus can serve as well (see e.g. https://doi.org/10.1098/rsta.2011.0081).
1.3. Note that failure of validation can be due to problems in EEG quality.

2. Next, the validated EEG/ERP data can be used for analyses. Two examples:
2.1. Compare the microstate maps and dynamics parameters between a control group and a patient group (see e.g. https://doi.org/10.1016/j.pscychresns.2004.05.007).
2.2. Compare brain function, as quantified by cortical electric neuronal activity using LORETA, in a control group, under different conditions. Comparison of brain function consists of difference in localization of cortical activity, and difference in effective connectivity (see e.g. https://doi.org/10.1016/j.cnp.2017.09.002).

All statistical analyses are carried out with the highest methodological standards as used in the vast functional imaging literature