event-related HRF estimation with double gamma versus tent function (versus GLMsingle)

AFNI Message Board
1

Dear AFNI experts,

I have an experiment, which is modeled after this paper.

I'm interested in measuring repetition suppression across conditions with HRF estimation, where each event (two brief picture presentations) lasts for 1 sec with 2-4 sec of ITI (TR = 1 sec). There are 20 trials per condition within each run.

This particular paper used FSL, and they stated they used a double-gamma function, but would it make more sense to use the tent (tentzero) function with 3dDeconvolve when using AFNI (compared to the double-gamma option)?
Unlike this paper, my experiment is not TR-locked.

I'm also curious about your opinion on using GLMsingle versus TENTzero for this paradigm if you have experience with both.

2

If the goal is to estimate condition-level effects rather than trial-level effects, I generally recommend using a hemodynamic response estimation approach with basis functions, such as TENT or CSPLIN. Non-TR-locked stimulus timing is actually advantageous for improving estimation accuracy, as it enables sampling across a broader range of time points.

For trial-level effect estimation, GLMsingle is currently the more practical option.

Gang Chen

3

Great. Thanks for this!