EEG Source Reconstruction with eLORETA: Choosing the snr, normalising source time courses, removing subcortical structures effect and spatial resolution

[richard (Richard Höchenberger)]

@Rohmer

• I appreciate your clarification about choosing the right lambda2. How would you go around setting this parameter given the inherent circularity in picking a good value? Is sensor level snr as can be guessed through evoked.plot_white(noise_cov_reg, time_unit="s") or other means truly a wrong proxy for source level snr?

For evoked data, set SNR to 3
For continuous data, set it to 1

See:

Estimating the regularization parameter for HCP MEG resting state source reconstruction

@Dominik I just asked @agramfort about this while we were fighting with the coffee machine (spoiler: we won! ) He said this parameter (SNR of 3 for averaged, 1 for non-averaged data) “was established by Matti Hämäläinen 20 years ago”, and that “no one touches this parameter”. Hence … I would say, case closed. Best wishes, Richard