Dear FSL Experts
I have a question regarding, for example, how a statistical image is transformed into an uncorrected p-map (or the 1-p map in the output).
What I mean is that during the permutation, if we do 1000 permutations, each voxel will have a null-distribution of the specific statistic at hand consisted of 1000 observations of that voxel. If I have 30000 voxels in the image, then I will have 30000 individual null distributions. If I want to change this statistic image into uncorrected-p maps, should I use the null-distribution from each particular voxel (the specific one from the 30000 distributions corresponding to the particular voxel) separately for each voxel?
Or should I pick the maximum statistic across the whole image (that is the value of the highest voxel) for each permutation, then I will end up with only “one” null-distribution with 1000 observations for the whole image, and then I will change each statistic value in the voxel into p-values by this one common null-distribution for the whole image?
Thank you very much!
Chen-Chia
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