Hi AFNI experts,
I will do gPPI analysis to my fMRI data with event-related design. I read the tutorial of gPPI (https://afni.nimh.nih.gov/CD-CorrAna) and I have some questions :
1) How to select a impulse response function in step 3?
A impulse response function is assumed firstly. And then the seed time series is deconvolve (step 3) and Inter_neuA.1D is convolved (step 4) using this response function. Whether some certain requirements for selecting a response function need satisfying? For example, I think it will be better to choose a response function which is the same as the one used in the following GLM regression (step 6). Which function should I choose if the Rmodel used is 'BLOCK5(1,1)' in the following GLM regression?
2) What other modification should I make on the template to make it suite my situation?
The script provided by the link mention above is a template for block design fMRI deconvolved using the Rmodel 'BLOCK(3,1)' in the GLM regression. Whether there are some key difference in the gPPI operation between a block design data using 'BLOCK(3,1)' and my event-related data using 'BLOCK5(1,1)' in the following GLM regression?
3)Whether the signals in the input file pb04.* mentioned in the above link have been scaled to percentages? Need I scale each voxel time series to have a mean of 100 before gPPI?
4)Could you provide more learning materials or links with more detail on how to do gPPI in AFNI ?
I am very sorry to post so many questions to trouble you. But I will be very appreciated with your answers!
Thank you!
Po



Edited 1 time(s). Last edit at 03/22/2017 01:41PM by Ren Po.