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help > RE: Inconsistent ROI-ROI results
Jan 27, 2017 04:01 PM | Alfonso Nieto-Castanon - Boston University
RE: Inconsistent ROI-ROI results
Hi Isabella,
Yes, it is a 'property' of gPPI analyses that they are directional (the ROI1-ROI2 effect is not the same as the ROI2-ROI1 effect, even if you use correlation measures). See this post ( http://www.nitrc.org/forum/message.php?m... ) for additional details. I will see if I can easily add into the next release an option to force symmetric/non-directional results in gPPI analyses to avoid this somewhat confusing behavior.
Best
Alfonso
Originally posted by Isabella Breukelaar:
Yes, it is a 'property' of gPPI analyses that they are directional (the ROI1-ROI2 effect is not the same as the ROI2-ROI1 effect, even if you use correlation measures). See this post ( http://www.nitrc.org/forum/message.php?m... ) for additional details. I will see if I can easily add into the next release an option to force symmetric/non-directional results in gPPI analyses to avoid this somewhat confusing behavior.
Best
Alfonso
Originally posted by Isabella Breukelaar:
Hi CONN experts,
I did an ROI-ROI gPPI analysis in CONN using a region in the parietal cortex as a seed and extracted connectivity values ROIs in the frontal and anterior cingulate cortices. I then did the same using the frontal ROI as a seed and extracting connectivity values for ROIs in parietal cortex. When I look at the results, they are quite different depending on it is a parietal seed to my frontal ROI vs a frontal seed to the same parietal ROI, however I would have expected that these results be the same. Would anybody be able to explain to me why connectivity would change between the exact same two regions depending on which one was selected as the seed?
Thanks,
Isabella
I did an ROI-ROI gPPI analysis in CONN using a region in the parietal cortex as a seed and extracted connectivity values ROIs in the frontal and anterior cingulate cortices. I then did the same using the frontal ROI as a seed and extracting connectivity values for ROIs in parietal cortex. When I look at the results, they are quite different depending on it is a parietal seed to my frontal ROI vs a frontal seed to the same parietal ROI, however I would have expected that these results be the same. Would anybody be able to explain to me why connectivity would change between the exact same two regions depending on which one was selected as the seed?
Thanks,
Isabella
Threaded View
| Title | Author | Date |
|---|---|---|
| Isabella Breukelaar | Jan 24, 2017 | |
| Alfonso Nieto-Castanon | Jan 27, 2017 | |
| Isabella Breukelaar | Jun 14, 2019 | |
| premurax | Dec 19, 2020 | |
| premurax | Dec 23, 2020 | |
| Isabella Breukelaar | Jan 30, 2017 | |