Posted by B. Douglas Ward on March 12, 2001 at 11:04:00:
In Reply to: after 3dTcat posted by Denise Wu on March 09, 2001 at 18:10:12:
Denise:
To reduce the number of false positives, it may be helpful to enter the
estimated motion parameters as additional regressors (i.e., "ort" functions
in 3dfim+, or "stim" functions in 3dDeconvolve). Program 3dvolreg will (as an
option) write the estimated motion parameters to a file which can then be used
as input to the time series analysis.
If you are using 3dDeconvolve for the time series analysis, it is not
necessary to use the -rlt option of 3dTcat. However, it IS necessary
to use the -concat option of 3dDeconvolve, to let 3dDeconvolve know where
the different runs are concatenated together. The program will then estimate
a separate constant and slope for each run. See the documentation in file
3dDeconvolve.ps for more details.
Please try to balance the experiment across runs. That is, if possible, the
different experimental conditions should be represented equally in each of
the runs, so as to prevent confounding of the treatment effect with the
run effect.
Doug Ward