Dear Lisa,
to do a conjunction of group-level one-sample t-tests, I typically use the minimum-statistics approach by Nichols et al. (2005) - that is, you simply take the minimum of 2 thresholded maps. See this thread: https://www.jiscmail.ac.uk/cgi-bin/wa-jisc.exe?A2=ind2108&L=SPM&D=0&X=D6A0911B6773C01F93&Y=kuhnke%40cbs.mpg.de&P=41228
Here is my code to do this using the SPM batch (imcalc):
clear matlabbatch
matlabbatch{1}.spm.util.imcalc.input = {
path_to_image_1;
path_to_image_2
};
matlabbatch{1}.spm.util.imcalc.output = 'conjunction.nii';
matlabbatch{1}.spm.util.imcalc.outdir = {'my_output_folder'};
matlabbatch{1}.spm.util.imcalc.expression = 'min(X)';
matlabbatch{1}.spm.util.imcalc.var = struct('name', {}, 'value', {});
matlabbatch{1}.spm.util.imcalc.options.dmtx = 1;
matlabbatch{1}.spm.util.imcalc.options.mask = -1;
matlabbatch{1}.spm.util.imcalc.options.interp = 0;
matlabbatch{1}.spm.util.imcalc.options.dtype = 16;
spm_jobman('run',matlabbatch);
I hope this helps!
All the best,
Philipp Kuhnke
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