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I also tried anther task-related fMRI, which has similar parameter, list as follow:
0 1 16 1 move
17 0 16 1 blank
33 2 16 1 static
49 0 16 1 blank
65 1 16 1
81 0 16 1
97 2 16 1
113 0 16 1
129 1 16 1
145 0 16 1
161 2 16 1
177 0 16 1
193 1 16 1
209 0 16 1
225 2 16 1
241 0 16 1
to build the contrast, i use the command mkanalysis-sess -fsd bold -analysis odd.sm5.fsaverage.lh -surface fsaverage lh -fwhm 5 -paradigm move-vs-static.par -event-related -spmhrf 0 -refeventdur 16 -TR 2 -nconditions 2 -polyfit 2 -per-run mkcontrast-sess -analysis odd.sm5.fsaverage.lh -contrast MTlocalizer -a 1 -c 2 -nosumconds the contrast matrix is [1 0; 0 -1], which is correct. However, the result still show the activation the same with move-vs-blank. Every procedure was finished with out error. I re-run many times but met the same problem. Any idea what might be going wrong, or what I can do to fix such a confusing problem? Thanks!!
Best, Star
---------- Forwarded message --------- From: xi star starxifd@gmail.com Date: 2019年1月9日周三 下午1:26 Subject: problem with contrast in 1st-level analysis To: freesurfer freesurfer@nmr.mgh.harvard.edu
Hi! FS Experts! In the fMRI experiment, there are 2 conditions: 1# 3D picture 2# zero disparity picture interleaved with fixation block (0).
To compare 3D-vs-zero disparity, I used command: mkcontrast-sess -a 1 -c 2 -nosumconds but the results showed more activation then expected. To find the problem, I compared 3D-vs-fix (-a 1 -c 0), the result shows the same as 3D-vs-zero disparity. My question is: why the two contrast ( [1 0; 0 -1] and [1 0] ) came to the same result? How can I compared the two conditions? Thanks a lot ! Yours, Star