Hello,

I am interested in combining three thresholded language activation maps within a single subject. The three language tasks are similar (block-related designs) and tend to produce some degree of overlapping clusters in the major language regions. My goal is to summarize the language-related activation clusters in a clean and statistically relevant manner.

I am somewhat new to ANFI and recently came across the 3dmerge program with options to perform Fisher transformation on intensity data (-gfisher) or thresholded data (-tgfisher). This seems to accomplish my main goal, but I am concerned about potentially violating certain assumptions associated with the Fisher method, namely the assumption of independence (i.e., each language task is expected to produce relatively similar activation patterns, thus not independent?). I am curious to hear from the experts on this forum about three main things:

1. Does it make sense to be concerned about combining non-independent thresholded correlation maps within a single subject using 3dmerge –tgfisher or -gfisher?
2. Are there other issues with this approach that stand out?
3. Are there other methods of statistically combining thresholded activation maps within a single subject that may be better than the fisher method?

Thank you in advance for your feedback.