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Hi Xuelin, why don't you start with http://www.fmrib.ox.ac.uk/fslcourse/lectures/intro1/mri_fmri_intro_slides.pdf , see page 49 in particular. Or join one of the next FSL courses. I know - it is a long trip from Hawaii but it may be worth it. Lets say you have a boxcar type of experiment (see page 42 of the pdf), you can model this be a series of "0" and "1" entries. You can simply take this vector and correlate with the t*.txt from melodic's output. Alternatively, you may want to convolve your expected response vector with a hemodynamic response function - e.g. a synthetic like the double-gamma HRF or even an empirical one obtained specifically for your type of stimulus / brain region / experiment. Hope this helps- Andreas ________________________________ Von: FSL - FMRIB's Software Library im Auftrag von Xuelin Cui Gesendet: Sa 31.03.2007 00:07 An: [log in to unmask] Betreff: Re: [FSL] AW: [FSL] how to relate each IC to different tasks? hi Andreas: Thanks for your reply. But I dont totally understand what you said. Could you please explain a little bit more on that: "However, you can simply correlate your design (boxcar or, for event-related studies namely, your stimulus-/response-ons convolved with some type of HRF)" What is a HRF? Do you have an example, or a relevant paper? Thanks Xuelin **************************************** Xuelin Cui Department of Electrical Engineering University of Hawaii-Manoa Honolulu HI 96822 Tel: 1-808-349-0983 Email: [log in to unmask] **************************************** ----- Original Message ----- From: Andreas Bartsch <[log in to unmask]> Date: Tuesday, March 20, 2007 3:26 pm Subject: [FSL] AW: [FSL] how to relate each IC to different tasks? To: [log in to unmask] > Hi, > Strictly speaking: you can't (- at least not by just running a > single experiment and analysing it;) > However, you can simply correlate your design (boxcar or, for > event-related studies namely, your stimulus-/response-ons > convolved with some type of HRF) with the time-course (in SD > units) of the respective tXX.txt file. Or even easier, if you have > no spatial hypothesis whatsoever, select those Ics whose FFT are > peaking at the appropriate frequency and then look at the time- > courses, if they are synchronous to your paradigm. > Hope that helps- > Andreas > > -----Ursprüngliche Nachricht----- > Von: FSL - FMRIB's Software Library [mailto:[log in to unmask]] Im > Auftrag von Xuelin Cui > Gesendet: Dienstag, 20. März 2007 00:55 > An: [log in to unmask] > Betreff: [FSL] how to relate each IC to different tasks? > > hi folks: > > I here have a question. I am doing the ICA analysis on fMRI data. > But I am confused on how to relate rach IC extracted from the fMRI > data to different tasks. Put in this way: if I see an IC, how can > I tell the IC is caused by what kind of reason? > > Anyone could give any suggestions? I really appreciate your thoughts. > > Thanks > > Xuelin > > **************************************** > Xuelin Cui > Department of Electrical Engineering > University of Hawaii-Manoa > Honolulu HI 96822 > > Tel: 1-808-349-0983 > Email: [log in to unmask] > **************************************** >