Computational NeuroscienceAlgorithm to find high density EEG scalp coordinates and analysis of their correspondence to structural and functional regions of the brain

•We propose an algorithm to automatically calculate EEG electrode positions on a mesh.•We calculate positions following standard layouts on the scalp of 20 adult subjects.•We present an algorithm to parcellate the cortex based on electrode proximity.•These parcellations are compared to anatomical and functional cortical regions.•We offer a reference table for experimental design and initial analysis of EEG data.

BackgroundInterpretation and analysis of electroencephalography (EEG) measurements relies on the correspondence of electrode scalp coordinates to structural and functional regions of the brain.New methodAn algorithm is introduced for automatic calculation of the International 10-20, 10-10, and 10-5 scalp coordinates of EEG electrodes on a boundary element mesh of a human head. The EEG electrode positions are then used to generate parcellation regions of the cerebral cortex based on proximity to the EEG electrodes.ResultsThe scalp electrode calculation method presented in this study effectively and efficiently identifies EEG locations without prior digitization of coordinates. The average of electrode proximity parcellations of the cortex were tabulated with respect to structural and functional regions of the brain in a population of 20 adult subjects.Comparison with existing methodsParcellations based on electrode proximity and EEG sensitivity were compared. The parcellation regions based on sensitivity and proximity were found to have 44.0 ± 11.3% agreement when demarcated by the International 10-20, 32.4 ± 12.6% by the 10-10, and 24.7 ± 16.3% by the 10-5 electrode positioning system.ConclusionsThe EEG positioning algorithm is a fast and easy method of locating EEG scalp coordinates without the need for digitized electrode positions. The parcellation method presented summarizes the EEG scalp locations with respect to brain regions without computation of a full EEG forward model solution. The reference table of electrode proximity versus cortical regions may be used by experimenters to select electrodes that correspond to anatomical and functional regions of interest.