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Dear SPM users, a question about significance levels. We have done a second level analysis using a 2 sample t-test between 2 groups (13 pts vs 13 controls) using a pre-defined ROI on basal ganglia. Is it correct to consider significantly different between the two groups foci of activation displayed at a incorrected p =.001 and Z> 3.09, even if I used a small ROI? Considering that fMRI activation in BG is consistently smaller (30%) than in other structures can we consider significant activations foci diplayed at a higher p (p=.01, Z >2.33)? About covariate (simple regression analysis), we are still using small ROI for the analysis. Which levels of significance indicates correlations between activation foci and my covariate of interest? Any reference I can check at this regard on SPM99? Thanks Francesca