Hi --
I'm working on analysis: we're collecting 4-6 runs per subject,
event-related design, collapsing across runs at the second level and across
subjects at the third level.
I've been having a problem with NaNs appearing in my data starting after my
second-level, and going on to produce errors at the third level. The number
of NaNs in the second-level cope1.nii.gz files is always the same for any
given subject, both for all the copes in my current analysis and even across
analyses. The NaNs always occur around the edge of the brain.
We think the problem may be related to something happening during smoothing.
In the second level log file we're getting lines that look like this:
Post-stats
/usr/local/fsl/bin/fslmaths stats/zstat1 -mas mask thresh_zstat1
echo 309240 > thresh_zstat1.vol
zstat1: DLH=nan VOLUME=309240 RESELS=nan
/usr/local/fsl/bin/cluster -i thresh_zstat1 -c stats/cope1 -t 2.3 -p 0.05 -d
nan --volume=309240 --othresh=thresh_zstat1 -o cluster_mask_zstat1
--connectivity=26 --mm --olmax=lmax_zstat1_std.txt > cluster_zstat1_std.txt
We're not sure where those NaNs are coming from since these same numbers
look normal for all runs in the first-level log files, e.g.:
echo 26833 > thresh_zstat1.vol
zstat1: DLH=0.641048 VOLUME=26833 RESELS=7.21775
Does anyone have any ideas what might be happening?
-Bethany Weber
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