[Mne_analysis] Noise estimation in EEG

octavian lie octavian.lie at gmail.com
Sat Nov 24 09:47:35 EST 2012
Search archives:

Dear All,

Here is a fundamental question that has been answered in a conflicting way,
related to EEG spike or ERP analysis.

When estimating the noice covariance matrix C of an EEG (data matrix nxt,
n=no of electrodes, t=time), should one chose the identity matrix (no
assumptions of the brain and measurement noise) or the one calculated on
baseline pre spike/prestim epoch? Some think that for EEG, as opposed to
MEG, estimating noise is not a good idea, whereas others think it should be
ok. (this in the contexs of gaussian and noncorrelation assumption about
noise).
Also, if I should calculate the noise covariance matrix, since I am working
with average spikes (calculated from a known no of individual, raw,
spikes), should I correct in any way the noise covariance matrix by the no
of spikes, and if yes, how do I do it?

Thank you,

Octavian.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://mail.nmr.mgh.harvard.edu/pipermail/mne_analysis/attachments/20121124/5ffcdced/attachment.html 


More information about the Mne_analysis mailing list