Dear Xi,
concerning the ROI analysis, it depends on how you defined the ROIS.
If you used activation clusters in the one-sample t test to conduct
regressions on individual differences, it is very unlikely that you
are doing double dipping. The issue is discussed in
https://www.ncbi.nlm.nih.gov/pubmed/19900563
Best,
Roberto Viviani
Quoting Xi Yu <[log in to unmask]>:
> Dear experts,
>
>
>
> I have a question regarding statistical analyses that I wish to get your
> thoughts on. I have two groups, one clinical and one control. I first
> conducted multivariate pattern analyses, and found a few regions showing
> distinctive activation patterns between the two groups. I then ran
> traditional ROI analyses in each of these regions, and found higher
> activation for the clinical group in one region, higher activation for the
> control group in one other region, and no differences in the remaining
> regions. Some co-authors are concerned that these analyses are double
> dipping, since the second one was conducted in regions derived from the
> first one. However, I don?t think so, as you can see from the results that
> the first analyses do not associate with any specific pattern in the second
> one.
>
>
>
> Could someone please share his/her opinions on this issue?
>
>
>
> Thanks very much for your help!
>
>
>
> Bests,
>
>
>
> Xi Yu
>
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