It’s my first time working on an fmri dataset! I preprocessed with fmriprep and I’m using SPM25 for analyses. 1st level GLM was specified with SPM25. Now I am working on group level analysis and I am wondering if it’s possible to create a montage of corrected stats showing both positives and negatives in SPM. Or if there is a plug-in to SPM where I can use a slider for viewing purposes. I tried xjview but it’s buggy. What do people use to cluster correct when working with SPM and can you see positive and negative at the same time?
For the viewing part, Nilearn’s view_img gives an interactive signed map; plot_stat_map can make a static slice montage. Both support diverging colours for positive and negative values. Their display threshold is not a cluster-corrected p-value: apply the significance mask from the statistical analysis, then visualise the signed statistic within it.
Which group contrast are you testing, and do you want cluster-level FWE or voxel-level FWE? SPM T-contrasts are directional, so combining a positive and a negative result each at 0.05 does not automatically give 0.05 error control across both signs.