clarification

[a.stolk@fcdonders.ru.nl]

Hi Odelia,

As far as I can help, I think it depends on your set-up + hypotheses.

Do you have both/multiple conditions in one block? If not, reference periods might be different over blocks biasing your results. Check whether they're comparable.

Do you expect major changes over time (e.g. fatigue, habituation)? If so, perhaps take another reference period after or from a pause in the experiment and average.

Generally, the longer your reference period, the more robust the activity estimation. However, depending on your set-up, subjects might start doing other things..

Finally, if you don't trust your baseline/reference period, you could choose to look at the relative differences between conditions directly. Check out ft_freqcomparison although I think it does not support TFR data (yet).

Best,
Arjen

----- Original Message -----
From: "Odelia Goldberg" <odidodi at HOTMAIL.COM>
To: FIELDTRIP at NIC.SURFNET.NL
Sent: Tuesday, July 13, 2010 1:58:26 PM GMT +01:00 Amsterdam / Berlin / Bern / Rome / Stockholm / Vienna
Subject: [FIELDTRIP] clarification

Hi again,
I use the term "base line correction" in a wrong way. I meant to say that I
need a reference period (comparable to "baseline type"-absolute/relative).
And a few more details. My trials are of different durations, and I thought
of calculating the mean of a few trials.
Thank you.
Odelia.

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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/neuroimaging/fieldtrip.

----------------------------------
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/neuroimaging/fieldtrip.