Hello Zheng,
activation3Dtimecourse is a file that contains perturbation of the T2*
( dT2* ) i.e. T2* is the baseline and is fixed for each different
tissue. Total T2* for each voxel is obtained by summing the two up
(T2*(voxel)=T2*fixed+dT2*(voxel)). You can find the value T2*fixed in
the MRparameters. You can specify this file your self as well if you
need. We chose values that were realistic (one for each of the
different tissue types).
dT2* is stored in activation3Dtimecourse and is the one you can
modulate to get the FMRI series.
Hope this helps,
Ivana
On 7 Dec 2009, at 16:36, Zheng Liu wrote:
> Hi all,
>
> When I used example 'activation3Dtimecourse' to do fMRI simulation,
> I found when the data in 'activation3Dtimecourse' is high, the
> correspond image intensity is low. In website, it shows that the
> 'activation3Dtimecourse' file means a modulation time coure. But in
> theory, if T2* high, the intensity will be high. Who knows what is
> 'activation3Dtimecourse' detailed means?
> Thanks,
>
> Zheng
> --
> Dr. Zheng Liu
> Postdoctoral student in Computer Vision and Image Analysis Lab
> Department of Electrical and Computer Engineering
> Texas Tech University, Lubbock, TX 79409
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