[Mne_analysis] MNE pca and SNR

[Marina Papoutsi]

Dear MNE users,

I have two questions that I hope someone can answer.

1) The first is about SNR. Following an older post that I made on SNR 
(left unaswered :-( ) I will attempt to rephrase the question, hoping to 
hear back from someone.

I am still wondering about how to best use the option --snr in 
mne_make_movie. I have played around with the data a bit and changing 
the SNR value seems to make a difference in the stc files.

So what is the best way to chose an SNR?
a) use the default value (3) independent of whether this is reflected in 
your data
b) estimate the mean SNR value (over the epoch time), which will be 
different for each subject and condition?

At the moment, I have calculated the SNR for each subject and condition. 
The SNR value is between 1 and 2 and it is different for subjects and 
conditions. Will that be a problem when I need to do group-level 
statistics comparing different conditions?

2) The second question is about PCA. Is there any function in MNE that 
would allow one to do a PCA on the *.fif files to remove eye-blinks or 
cardiovascular related oscillations?

Thank you in advance for the help,
Marina