3dTproject and consecutive censored volumes (plus another question)

AFNI Message Board
1

Hi,

I am wondering if there are any recommendations to exclude a subject or chop of the entire beginning or end of a scan if there are more than a certain amount of consecutive censored volumes.

I am also wondering if kill-mode censoring affects bandpassing as it is altering the temporal structure of the data.

Thanks,
Aaron

2

Hi Aaron,

There are certainly instances where that would seem reasonable. It would be strange to include 3 or 4 time points early in a run when the next 25 are censored, for example. But coming up with a concrete and reasonable method for exactly when to do such a thing might be difficult, especially since it would depend so heavily on the experiment design. Still, doing such a thing seems justifiable.

We suggest performing the entire linear regression (including just projection) in a single model, which includes band passing and censoring, as well as any other desirable or undesirable components in the model. That is how afni_proc.py does it, so you can use that to see an example if you have not already done so.

Right, it would not be reasonable to band pass kill-mode censored data (unless the band pass terms were similarly truncated - again that is most straightforward to do in one model).

  • rick
3

Thank you for the answer!

“Right, it would not be reasonable to band pass kill-mode censored data (unless the band pass terms were similarly truncated - again that is most straightforward to do in one model).”

Does 3dTproject do this? That is, kill TRs of the regressors along with the resting-state? (I imagine it would have to do so, or else it wouldn’t work…)