AFNI Message Board

Dear AFNI users-

We are very pleased to announce that the new AFNI Message Board framework is up! Please join us at:

https://discuss.afni.nimh.nih.gov

Existing user accounts have been migrated, so returning users can login by requesting a password reset. New users can create accounts, as well, through a standard account creation process. Please note that these setup emails might initially go to spam folders (esp. for NIH users!), so please check those locations in the beginning.

The current Message Board discussion threads have been migrated to the new framework. The current Message Board will remain visible, but read-only, for a little while.

Sincerely, AFNI HQ

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Ryan
March 05, 2010 02:16PM
I've been playing around with creating impulse response functions using the TENT response model. I have a question about the following warning that I have seen. I'm not sure what the consequences are

...
*+ WARNING: -stim_times 1 .. TENT(-3,18,22) has inter-knot TR=1 but -iresp output TR=3
...

I believe this stems from the fact that I have a 3 s TR (data sampling) and am trying to model the response at a higher resolution (1 s). Although I get the warning, 3dDeconvolve still produces reasonable response functions. What is the real issue here? Am I overfitting the data? Are the statistics associated with each TENT coefficient over-estimating significance? Perhaps because the same raw data is contributing to so many of the basis function estimates. Are the coefficient estimates corrupted by this oversampling? And finally, if I really only care about the shape of the response (e.g., to pull out the "peak" over some range), is this warning a problem?

Thanks,
Ryan
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Subject Author Posted

3dDeconvolve and TENT resolution

Ryan March 05, 2010 02:16PM

Re: 3dDeconvolve and TENT resolution

Gang Chen March 05, 2010 03:22PM