Hi Jeanette,
Thanks very much for your response. I believe the original ROIs were based on earlier work - which seems good. My interest is with the apparently arbitrary values selected subsequently. If you have an a priori ROI and find no robust effect when you constrain your analysis to that ROI, is it valid to then 'search' around that ROI, find a weak effect (p 0.05 uncorrected) and then use that to define your new ROI?
Cheers
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