Hi Keely,

> Are dual_hit#0 and dual_hit#1 the first regressor (intensity) and its derivative?
> (and dual_hit#2 is the reaction time regressor and dual_hit#3 its derivative?)

Yes I believe your interpretation is correct.

> -expr 'sqrt((a^2)+(b^2))' \

Using that value for group analysis could be problematic, and I think there is some discussion about its limitations in the literature.

> Should I use only the dual_hit#0 sub-brick for the 3dttest++ input?

Yes definitely as a first step you should try it out and see if it's consistent with your BLOCK5(1,1) results.

> How do I account for the SPMG2 modeling of the data with the derivative files?

If you want to model the subtle shape difference in BOLD response, maybe TENT is a better approach? The you can use 3dLME to run group analysis.

If you prefer to stick with SPMG2, one alternative for group analysis is this: reconstruct the BOLD response through -iresp in 3dDeconvolve. Then you can use those values and run 3dLME.

Gang



Edited 2 time(s). Last edit at 07/15/2013 03:56PM by Gang.