[FieldTrip] freqstatistics with sbj_chan_freq

[Vitória Piai]

Hi all,

I'm kinda stuck not being able to figure out what's going wrong with my 
freqstats, so I thought I could share it here and see if anyone can see 
where I'm going wrong.
When I run freqstatistics on TFRs, I get a negative cluster (p = .001) 
between 8 and 25 Hz with the topography very similar to the one in the 
figure. But I just want non-time-resolved spectra.
So I have power spectra calculated with mtmfft (dpss tapers) between 1 
and 50 Hz (5 Hz smoothing) and this is the one for which I've been 
trying to run freqstatistics, unsuccessfully.
I'm using a pretty standard cfg for freqstats (basically, the same I use 
for the TFRs, which give me the negative cluster with p =.001) and the 
data in the comparison are structured as sbj_chan_freq. With this 
time-unresolved data, only posclusters are detected, with ps > .4! If I 
plot the stat output, it has the exact same negative cluster as I get 
for the TFRs (see Figure), and as far as I can see, no real positive 
cluster, but the function doesn't even detect any negative clusters.
I must be doing something wrong because the time-resolved and 
-unresolved effects are pretty much the same in the descriptives. I 
remember running stats on time-unresolved data before and getting a 
reasonable output, so I guess my ft_freqstatistics isn't working well 
right now. I just can't figure out why.
Does anyone have any tips for how I could go about to find out why the 
negative clusters are being disregarded?

Thanks a lot, Vitória
-------------- next part --------------
A non-text attachment was scrubbed...
Name: freqstats.gif
Type: image/gif
Size: 28839 bytes
Desc: not available
URL: <http://mailman.science.ru.nl/pipermail/fieldtrip/attachments/20140413/f42f765c/attachment-0001.gif>