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MICA-MNI / ENIGMA

The ENIGMA Toolbox is an open-source repository for accessing 100+ ENIGMA statistical maps, visualizing cortical and subcortical surface data, and relating neuroimaging findings to micro- and macroscale brain organization. 🤠
https://enigma-toolbox.readthedocs.io
BSD 3-Clause "New" or "Revised" License
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Question about the function load_sc in enigma toolbox #26

Closed WY-SHI closed 1 year ago

WY-SHI commented 1 year ago

Hi, thank you for providing the efficient toolbox. Recently, I checked the Structural Connectivity data return by load_sc, but I found the values in the matrix have negative ones with the parcellation ['schaefer_100', 'schaefer_200', 'schaefer_300', 'schaefer_400', 'glasser_360'], except 'aparc'. Are these negative values normal?

saratheriver commented 1 year ago

Hello!

Yes, they are absolutely normal. This is because the group-average normative structural connectomes were defined using a distance-dependent thresholding procedure (https://doi.org/10.1162/netn_a_00075)—which preserves the edge length distribution in individual patients—and were log transformed to reduce connectivity strength variance.

In the higher resolution parcellations (eg 100+), some parcels had a fraction value, and since we are taking the log, then it becomes a negative value.

Hope this clears things up,

Sara.