ss_review_basic output

AFNI Message Board
1

Hi all,

Sorry for this basic question, but I’m having a bit of trouble interpreting the output of the ss_review_basic script. It says that there are 58 TRs above the motion limit (which is not surprising given that we’re scanning kids), and 9 above the outlier limit, but then the total number of censored TRs is 88. Why is this number so much higher than the combined number of TRs censored due to motion/outliers? Is there some additional censoring going on that I forgot about?

Thanks,
Laura

2

Hi Laura,

That is actually why both numbers are reported, they are usually different.
Censoring based on motion parameters (as opposed to base on outliers)
comes from an estimated changed in subject position between 2 time points.
But we cannot tell during which time point the motion occurred, possibly
during both. So by default, both time points are censored.

So if C time points are above the censor limit, censoring will be between
C (if C is zero, or C+1 if motion time points are contiguous) and 2C, if
none are adjacent.

  • rick