Dear FSL list,
I have a question about how to go about doing a 2nd level FIR analysis
with Randomise and TCFE:
Basically I am interested just localizing one specific (event-related)
activity in the brain in a group of 12 subjects. I use a FIR basis set
of 10 time bins at single-subject level.
I did all the first-level analysis in SPM, and have made contrast
images, one for each of the 10 bins, so I have 120 images for
Randomise that I put into 1 4D file.
I then made a design matrix with Glm.. The design looks like this (the
contents of 4D file to the left):
Sub1Bin1 1 0 0 ... etc, until 10 rows
Sub1Bin2 0 1 0 ...
Sub1Bin3 0 0 1 ...
Sub1Bin4 0 0 0 ...
Sub1Bin5 0 0 0 ...
Sub1Bin6 0 0 0 ...
Sub1Bin7 0 0 0 ...
Sub1Bin8 0 0 0 ...
Sub1Bin9 0 0 0 ...
Sub1Bin10 0 0 0 ...
Sub2Bin1 1 0 0 ...
Sub2Bin2 0 1 0 ...
...
... etc, until Sub12Bin10.
I also make 1 T-contrast for every bin and 1 F-contrast over all bins
(and save it). The design matrix looks like:
Then I adjust the design.grp file (to adjust the exchangability
blocks) so that each subject has its own ID (so that Randomise will
swap subjects with each other and not time bins within subjects).
Later on, i'll do the cluster and the atlasquiery commands with the
_tfce_corrp_fstat images to try to search for the significant
clusters.
Would this be the way to go about it (or am I missing something
essential), or would you recommend a better way to go about it?
Thanks for your time and kind regards,
Johan
Johan van der Meer
CANLAB, Dept. of Neurology
Otto v. Guericke University
Leipziger Str. 44
D-39120 Magdeburg
Tel: +49 391 61 17 536
Fax: +49 391 61 17 531
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