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help > RE: Dark Lines in the connectivity matrix
Aug 3, 2021 12:08 AM | Alfonso Nieto-Castanon - Boston University
RE: Dark Lines in the connectivity matrix
Dear Gucy,
That could indicate that those ROIs are found to be "outside of the brain" when attempting to extract functional data from them for those specific subjects (CONN ROI extraction procedure disregards any voxels with 0 values in the BOLD data). That could happen, for example, due to partial-coverage problems (e.g. if the functional data does not contain the lower portion of the cerebellum then some cerebellar ROIs will have no data) or it could also indicate some coregistration problem (e.g. if the ROIs are defined in MNI-space but the MNI-normalization of the functional data did not quite work correctly). I would probably suggest to go to the Setup.ROIs tab, select the Power264 atlas ROI and select one of the problematic subjects, and use the 'display ROI/functional coregistration' menu to try to evaluate whether there is enough coverage in the functional data for all of the ROIs in the atlas.
Hope this helps
Alfonso
Originally posted by gucy121:
That could indicate that those ROIs are found to be "outside of the brain" when attempting to extract functional data from them for those specific subjects (CONN ROI extraction procedure disregards any voxels with 0 values in the BOLD data). That could happen, for example, due to partial-coverage problems (e.g. if the functional data does not contain the lower portion of the cerebellum then some cerebellar ROIs will have no data) or it could also indicate some coregistration problem (e.g. if the ROIs are defined in MNI-space but the MNI-normalization of the functional data did not quite work correctly). I would probably suggest to go to the Setup.ROIs tab, select the Power264 atlas ROI and select one of the problematic subjects, and use the 'display ROI/functional coregistration' menu to try to evaluate whether there is enough coverage in the functional data for all of the ROIs in the atlas.
Hope this helps
Alfonso
Originally posted by gucy121:
Dear Alfonso,
I imported Power264 atlas and divided the brain into 264 ROIs. For the first-level analysis, I obtained a 264*264 matrix for each participant. However, for several participants, dark lines could be observed in the connectivity matrix and values for these ROIs are all zero (please check the link https://imgur.com/a/JfqUarm). However, there is no any error if I imported AAL90 atlas. Could you kindly give me some suggestions? Thank you so much!
Best,
Gucy
I imported Power264 atlas and divided the brain into 264 ROIs. For the first-level analysis, I obtained a 264*264 matrix for each participant. However, for several participants, dark lines could be observed in the connectivity matrix and values for these ROIs are all zero (please check the link https://imgur.com/a/JfqUarm). However, there is no any error if I imported AAL90 atlas. Could you kindly give me some suggestions? Thank you so much!
Best,
Gucy
Threaded View
| Title | Author | Date |
|---|---|---|
| gucy121 | Jul 30, 2021 | |
| Alfonso Nieto-Castanon | Aug 3, 2021 | |
| gucy121 | Aug 9, 2021 | |