Fmriprep report: crossed out boxes in nuisance regressor correlation heatmap?


For a few of my subjects, their fmriprep (v23.1.2) reports for the heatmap of correlations among nuisance regressors in RESTING STATE (but NOT task runs) have “crossed out” correlations, whereas the majority of my subject reports do not (they are just blank). Seems to also always be between non_steady_state_outlier00 and either dvars, fd, rmsd or a combination of these last three.

Why is this happening? Is this a non-issue?



Screenshot 2024-02-17 at 2.08.42 PM

Hi @ariveradom,

Short answer, a non issue.

This is likely because your first outlier might be happening on the first volume. In the three metrics with the cross, the first value is typically n/a, since metrics like FD are defined by volume-to-volume changes, so there is no initial value. I am guessing that since the only non-zero value happens on a N/A value of the other columns, it is leading to issues in the correlation function. Nothing to worry about.


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