freqanalysis_mtmconvol

[Ingrid Nieuwenhuis]

Hi Jeroen,



The cfg looks okay as far as I can see. Does freqanalysis say the correct
amount of trials when you call it? (It starts up with saying something like
"the input is raw data with . channels and . trials) If it does not say
anything like this, it could be that you are using an old version of
FieldTrip. (not that an old version could be an explanation for this
though). I have no idea what it could be, but probably it has to do with the
data set that you give in. Could it be that the trials do not all have the
same time axis, and that some trials are not from -0.5 to 2 seconds and
therefore omitted since cfg.toi = -0.5:0.05:2;

If not can you give some more information on your data, what are the time
axis of the trials, what did you do before calling freqanalysis?



Bests Ingrid

  _____

From: FieldTrip discussion list [mailto:FIELDTRIP at NIC.SURFNET.NL] On Behalf
Of Jeroen Geuze
Sent: Monday, July 09, 2007 12:22 PM
To: FIELDTRIP at NIC.SURFNET.NL
Subject: [FIELDTRIP] freqanalysis_mtmconvol



Dear Fieltrip team,



I'm using freqanalysis_mtmconvol to extract single trial TFR data. What I
noticed when running the code is that not all my trials end up in the 4D
powspctrm field of the result struct. I have used two datasets. One contains
193 trials and the other 324. When I run freqanalysis, I am left with 154
and 140 trials respectively in the rpt part of powspctrm. Is there a problem
here or is my fieldtrip ignorance playing up.

The config I used:



cfg = [];

cfg.output = 'pow';

cfg.channel = 'all';

cfg.method = 'mtmconvol';

cfg.taper = 'hanning';

cfg.foi = 5:1:40;

cfg.t_ftimwin = 4./cfg.foi; % 4 cycles per time window

cfg.toi = -0.5:0.05:2;

cfg.keeptrials = 'yes';



Thanks in advance for any help,





Jeroen Geuze

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----------------------------------
The aim of this list is to facilitate the discussion between users of the FieldTrip  toolbox, to share experiences and to discuss new ideas for MEG and EEG analysis. See also http://listserv.surfnet.nl/archives/fieldtrip.html and http://www.ru.nl/fcdonders/fieldtrip.
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