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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Robert Cox
April 25, 2005 09:26AM
The way the regression matrix (called R in some places, X in others) is assembled is

- censoring is ignored at first; all time points are modeled

- one column is inserted for each -polort regressor, for each imaging run (i.e., if polort=2 and there are 4 imaging runs, there are (2+1)*4=12 polort baseline regressors)

- one column is inserted for each -stim_file input, for each lag (but lagged data does not step pass imaging run boundaries)

- then, if -censor is provided, the rows of the matrix that have the censor value=1 are extracted to form the final X matrix; this has the effect of deleting any consideration of those time points, but the correct time sequencing of the baseline polynomials (i.e., the 't' value for time) is maintained.
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Subject Author Posted

baseline and censor

butterfly April 23, 2005 10:04PM

Re: baseline and censor

Rich Hammett April 24, 2005 02:29PM

Re: baseline and censor

Robert Cox April 25, 2005 09:26AM