Hi Everyone
I got the answer ! I was indeed missing the obvious. Sorry to have bothered you
Prerona
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Prerona Mukherjee
Post Doctoral Research Associate
Stonybrook University
Department of Psychiatry
Putnam Building, Room 142 A
Work: 631 632-8894
Mobile: 773 916 7662
On Fri, Apr 25, 2014 at 2:01 AM, Prerona Mukherjee
<[log in to unmask]> wrote:
> Hi
>
> I have a question regarding beta value extraction using marsbar and
> was wondering if you could please advise me.
>
> I have an fMRI experiment with 5 sessions and 3 conditions. I have run
> a gPPI analysis on this data. So I have SPM.mat files for each of my
> subjects with 40 conditions (5 * (3 task conditions + 3 PPI) + 5
> constants). I want to extract for 4 seeds
>
> I have a script that will loop through all my seeds and subjects. This
> is mainly the following lines with a wrapper for the looping, loading
> SPM & printing the values
>
>
> D = mardo(SPM);
> R = maroi(act_roi); %current roi
> Y = get_marsy(R, D,'mean');
> xCon = get_contrasts(D);
> E = estimate(D, Y);
> E = set_contrasts(E, xCon);
> b = betas(E);
>
> I am confused about the following
>
> 1) if the b (length 40) has the beta values I want, then there is one
> value for each session - how do I summarise this information?
>
> 2) using the process described here I extracted a "summarised beta
> values" for one subject manually:
> http://www.jessicagrahn.com/marsbar-extract-data.html
> but I am not sure how the summary is defined (I tried a average of the
> corresponding b values above (eg: Fear Sn 1 - 5) and it is not the
> same value
>
>
> I would really appreciate any help
>
> Sincerely
>
> Prerona
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