[FieldTrip] rereference to repaired channel

[Ingrid Nieuwenhuis]

Hi all,

I've measured EEG data with Cz as the reference. I now want to 
rereference to linked mastoids. However, in one participant one of the 
mastoid electrodes is really noisy. Is it valid to throw out the noisy 
channel, then fix it (with ft_channelrepair), and then rereference to 
this fixed mastoid channel? In other words, is channelrepair a linear 
operation? Or would I be mixing (a little) Cz into all channels now...? 
Any other options?

Or another way of asking: do I get the same result if I first 
rereference and then fix bad channels, compared to first fixing bad 
channels and then rereference? In the participant with the bad mastoid 
chan, I don't have a choice, I have to first fix the channel first, or 
I'd be mixing noise into all channels. But, in other participants, where 
I also have bad channels (but not the mastoid ones), does the order 
matter, which order is better? I'd think first rereference, then fix... 
Correct?

Thanks!!
Ingrid

-- 
Ingrid Nieuwenhuis PhD
Postdoctoral Fellow
Sleep and Neuroimaging Laboratory
Department of Psychology
University of California, Berkeley
California 94720-1650
Tolman Hall, room 5305