[Mne_analysis] Re: MNE support request

[Matti Hamalainen]

On Mar 30, 2009, at 9:46 AM, Lucie Charles wrote:

> Hello,
>
> I'm working at Neurospin in Paris with the new Neuromag MEG machine  
> and I'm trying to analyse my data with mne.
> We did an EEG-MEG recording and I averaged the data with the  
> following command line.
>
> mne_process_raw  --raw raw20090212bg_maskingError_run2_sss.fif --raw  
> raw20090212bg_maskingError_run3_sss.fif --raw  
> raw20090212bg_maskingError_run4_sss.fif --filteroff --projoff -- 
> digtrig STI101 --events Compl_20090212bg_maskingError_run2.txt  -- 
> events Compl_20090212bg_maskingError_run3.txt --events  
> Compl_20090212bg_maskingError_run4.txt --ave AveragebyMatlab.ave -- 
> gave grandaverage.fif --eventsout essai.eve
>
> I am not sure about one point : if I use the projoff option, what  
> does the program use as a reference electrode for the EEG ? I  
> thought that the reference was the average of all electrodes but it  
> doesn't look like it in the data.
> Could you please give some advice ?


Hi Lucie,

When you specify --projoff the EEG average reference projection is  
still included with the output file but the average EEG reference is  
not automatically switched on when you load the data to  
mne_browse_raw. To see the effect of the average electrode reference,  
go to "Manage averages..." and click on "Proj..." where you can switch  
the average EEG reference on and off.

However, when the inverse operator is created, the average EEG  
reference is switched automatically on.

- Matti