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Dear Vladimir,
 
Thank you for response.  I have tried to make do with multiple time windowed exported images, but it takes up a lot of time and is pretty crude, and I have no time left, unfortunately.
In order to build contrasts, will again take too much time, as preprocessing has been done with another software, therefore all my subjects and conditions are in different files, so when I merge files as in CA1+EA1 in order to build after a contrast [1 -1], I can't do CA1+EA1, as it will be ovewritten on the first merged file, so that after every merge, I have to separately save it in different name, and I might finally get lost around files?
I am afraid I don't know how to perform t-test on group of images, as they are saved in formats *.hdr, *.img, or are you talking about different kind of images? Thank you for your help,
 
Regards,
Antanas
 

From: Vladimir Litvak <[log in to unmask]>
To: Spokas Antanas <[log in to unmask]>
Cc: [log in to unmask]
Sent: Saturday, 15 August, 2009 16:09:49
Subject: Re: [SPM] eeg source reconstruction results

Dear Antanas,

I understand what you are trying to do, but in general I think it'd be
hard to build a good DCM model just based in imaging source
reconstruction without incorporating any prior knowledge from the
literature and theoretical conciderations.

If you have multiple subjects and conditions you should build SPMs for
the contrasts of interest and look at the areas that come up in these
contrasts. The next best thing would be to do just a single-sample
t-test for a group of images from the same time period for different
subjects. This is not valid statistical inference because all the
values in the images are positive, but you can look at the peaks of
the T-images as most consistently occurring sources.

Finally the most ad hoc approach is to export images for the time
periods of interest for single subjects and look where you find local
maxima in those images.

Best,

Vladimir

On Sat, Aug 15, 2009 at 3:48 PM, Spokas
Antanas<[log in to unmask]> wrote:
> Dear Vladimir,
>
> Thank you so much for your always prompt and helpful answers. Let me
> explain, why I think I need more elaborate results, which I am not sure
> how could be solved with contrast functions.
> I am trying to get MNI coordinates for DCM. First I wanted to see what
> solution could unrestricted imaging reconstruction give me according to my
> experiment data and then restrict solutions by given in the literature and
> compare if they would give me better evidence, if so, I could procede with
> those coordinates and construct DCMs. As result output only gives most
> active source coordinates at specified time point, it could be that several
> regions have the same time course of activation but with a slight difference
> in intensity, so that it won't show up at any time point, unless I procede
> with window/image function, but then for any other active voxels I have no
> info on their confidence levels. Is there something I could do with GUI? I
> am sorry if this doesn't look clear, if not, I could try to elaborate.
> Thank you again!
>
> Regards,
> Antanas
>
> ________________________________
> From: Vladimir Litvak <[log in to unmask]>
> To: Spokas Antanas <[log in to unmask]>
> Cc: [log in to unmask]
> Sent: Saturday, 15 August, 2009 15:06:49
> Subject: Re: [SPM] locations of stored ppm's and time courses of estimated
> sources files after eeg imaging source reconstruction
>
> Dear Antanas,
> Time course and PPMs are not stored but computed on the fly by the function
> spm_eeg_invert_display based on output of the inversion which is stored in
> the header file. Using the GUI is the simplest way to access them.  If you
> want to do statistics on activations you should use the standard pathway
> described in the manual.
> Best,
> Vladimir
>
> On 15 Aug 2009, at 14:55, Spokas Antanas wrote:
>
> Dear SPM,
>
> Could you please help me to locate files of stored ppm's and time courses of
> estimated sources after eeg imaging source reconstruction. Thank you very
> much!
>
> Regards,
> Antanas
>
>
>
>