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<div class="moz-cite-prefix">Dear Peter,<br>
<br>
regarding your first question, most people here at the Donders
actually repair bad channels. When computing the grandaverage over
subjects or doing some statistics across subjects, only those
channels which are in common for all datasets are used. Thus, if
having different channels damaged/rejected per subjects, you can
end up with a fairly low amount of channels. But, in the end it
depends pretty much on what channels you reject wrt your
hypothesis, e.g. having few occipital channels while being
interested in motor regions won't constitute a big problem, so no
need to interpolate. I leave the question whether it's a correct
thing to do up to you (imho: I wouldn't worry too much about it).<br>
<br>
Regarding your third question: In FieldTrip you can only compare
two conditions directly (at least when doing cluster-based
permutation testing). Also, any interaction needs to be setup
manually.<br>
<br>
Best,<br>
Jörn<br>
<br>
On 9/23/2012 3:14 PM, Peter Goodin wrote:<br>
</div>
<blockquote
cite="mid:A55BBE5A90EFC441A6FE147DF0DFE26EB60006@gsp-ex02.ds.swin.edu.au"
type="cite">
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<div style="direction: ltr;font-family: Tahoma;color:
#000000;font-size: 10pt;">Hi Fieldtrippers,
<div><br>
</div>
<div>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. </div>
<div><br>
</div>
<div>The most pressing questions I have are: </div>
<div><br>
</div>
<div>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? </div>
<div><br>
</div>
<div>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?</div>
<div><br>
</div>
<div>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?</div>
<div><br>
</div>
<div>Thanks for any help, </div>
<div><br>
</div>
<div>Peter</div>
</div>
<br>
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<br>
<pre wrap="">_______________________________________________
fieldtrip mailing list
<a class="moz-txt-link-abbreviated" href="mailto:fieldtrip@donders.ru.nl">fieldtrip@donders.ru.nl</a>
<a class="moz-txt-link-freetext" href="http://mailman.science.ru.nl/mailman/listinfo/fieldtrip">http://mailman.science.ru.nl/mailman/listinfo/fieldtrip</a></pre>
</blockquote>
<br>
<br>
<pre class="moz-signature" cols="72">--
Jörn M. Horschig
PhD Student
Donders Institute for Brain, Cognition and Behaviour
Centre for Cognitive Neuroimaging
Radboud University Nijmegen
Neuronal Oscillations Group
FieldTrip Development Team
P.O. Box 9101
NL-6500 HB Nijmegen
The Netherlands
Contact:
E-Mail: <a class="moz-txt-link-abbreviated" href="mailto:jm.horschig@donders.ru.nl">jm.horschig@donders.ru.nl</a>
Tel: +31-(0)24-36-68493
Web: <a class="moz-txt-link-freetext" href="http://www.ru.nl/donders">http://www.ru.nl/donders</a>
Visiting address:
Trigon, room 2.30
Kapittelweg 29
NL-6525 EN Nijmegen
The Netherlands</pre>
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