[FieldTrip] Neuromag sensor level stats

[Peter Goodin]

Hi Fieldtrippers,

I'm at a stage where I'd like to do statistical analysis on my ERF neuromag data, but don't really know where to begin. I'd like to do a cluster analysis, but the tutorial material is for a CTF system. I'm using a neuromag 306 channel which complicates matters somewhat due to the different sensor types. I've searched the mailing list but can't find any solid answers / example scripts.

The most pressing questions I have are:

1. Despite running the data through maxfilter and entering in the bad channels, occasionally one gets through (not the same one). I've used Fieldtrip's repairchannel function on the data, making sure to replace the channel only with like sensor neighbouring sensors. While I know this is a common method for fixing bad channels in EEG, does the same hold for MEG due to non-existent smearing of the signal? Is it best to keep the fixed channel(s) or just remove them from the stats analysis across all participants?

2. Given the three sensor types on the neuromag system, do I need to run three different cluster analyses (one for mags, one for xgrads, one for ygrads), each time specifying like sensor neighbours? Alternatively, If I'm not interested in the mags data, can I just  run one using the data from the combined gradiometers?

3. When examining for group x condition effects, would I use a three row design matrix with row 1 containing group, row 2 containing participants and row 3 conditions?

Thanks for any help,

Peter
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