Hello!
I have a repeated measure dataset, where all subjects were scanned twice (i.e., pre & post) with an interval of 7 days between scans by fMRI. After analyzing by FSL standard pipeline, I got very weird group-level results using insular as ROI.
Pre: the functional connectivity between insular and S1 is Bilateral NEGATIVE!!! (with a large number of voxels) Post: the functional connectivity between insular and S1 is positive (with a small number of voxels) And paired t-test (Post > Pre) found large areas of difference in the sensorimotor region.
This result seems very strange to me as previous research has suggested that the test-retest reliability of resting-state functional connectivity is quite high. However, I am still unclear as to why the sensorimotor region appears to have a negative correlation during the pre-test.
Do any experts have any suggestions on this result? Are there any additional pre-processing methods such as denoising or motion correction that could improve the results?
Many Thanks!!!
Hi,
Unexpected correlations between the insular and S1 regions could arise from factors like motion artifacts, physiological noise, or inaccuracies in region-of-interest definition. Group-level statistical analysis needs to be robust, ensuring outliers aren't skewing results. Also, the state of subjects during scans, like falling asleep, can impact results. Ensuring accuracy in each step can shed light on these unusual findings.
Hope this helps.
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