Code computing spatial transfer functions for EEG using idealized head models, obtaining fundamental limits on EEG's accuracy, source localization using increasing number of electrodes, generating spherical harmonics basis functions, plots for distance vs number of electrodes in EEG, etc.

Fundamental limits on EEG's accuracy, brain-to-scalp transfer function, and hierarchical-referencing strategy: The .zip file is available here. The folder contains 3 .m files. The main file to run is TotEMEEGSensing.m and (the term TotEM stands for Total Energy Minimization) for total energy minimization, and FundamentalLimitsOnSourceLocalizationAccuracy.m if you're interested in fundamental limits on EEG accuracy. The parameters are self-explanatory for the 4-sphere model of head for EEG generation. Note that for total power calculation (but not for source-localization fundamental limits), I assume that the signal generated on the surface of the brain is white, which is a somewhat conservative assumption: the actual signal will have slower changes.

The two supplementary files are compute_rho.m, which computes correlations of EEG signals measured at different distances, and compute_Ylm.m, which computes the spherical harmonic functions.

EEG accuracy vs number of sensors: The code is available here.

EEG interelectrode distance vs number of electrodes: for a human head of radius 9.1 cm, with electrodes all around the head. The code is available here.

Visualizing spherical harmonics: The code is available here.


Last modified: Mon Jun 22 08:04:36 EDT 2015