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Dear FSL experts, I'm running a seed-based resting state analysis on fMRI data. Now, I'd like to make some cluster corrections on my data, but I have some issues about FSL cluster command and the interpretation of results. first of all, with the smoothest command, I worked out the smoothness and I know the FWHM of the resels. My questions are: 1) I have used a z-fisher transformation on my data to stabilize the variance of my t-maps of correlation between the seed and the rest of the brain. should I use -i,--in,-z or --zstat for my filename of input volume? and should I use -t,--thresh or--zthresh for thresholding the input volume? I don't really understand the differences between these options. 2) I don't understand how this cluster correction is implemented in FSL. I report a statement from http://www.fil.ion.ucl.ac.uk/spm/doc/books/hbf2/pdfs/Ch14.pdf "If we have a two dimensional image with 100 resels, then the probability of getting one or more blobs where Z is greater than 3.8, is 0.049. We can use this for thresholding. Let x be the Z score threshold that gives an E[EC] of 0.05. If we threshold our image at x, we can conclude that any blobs that remain have a probability of less than or equal to 0.05 that they have occurred by chance." Then, why FSL -t,--thresh or--zthresh allows to specify any threshold with any -p,? what is the purpose of -t,--thresh or--zthresh, if what I really need is only -p? aren't they simply related by a function? I hope this is a non trivial question, help is really appreciated, All the bests, Marco