Dear Anja,
i don't think, that you will make your life easier, entering the
Designmatrix in the matlab window, becuase, during
the design specification, the designmatrix has a higher time resolution
than the final one. The reason for
that is, that all your specifications, SOAs etc, are convolved with your
basic function and after
that sampled down to one time-bin per scan (which time-bin is used can you
see in the 'fmri-statistic' defaults).
I think, one way, to make the specifications of your design quicker and
easier, is to create an matlab script,
for example 'soa.m' , where you can define all your paramteres, like SOAs,
additional regressors etc,
for exapmle:
soa_run1=[1 4 ... 42]
soa_run2=[ 2 5 ...]
regeressor_run1=[...]
...
When you want to specify your design, just run this script by 'utils -> run
m-file'
and all your paramteres are stored in your matlab workspace. During the
specification
of your fmri-design, you can now enter the variable names instead of the
values.
If you have the values of the regressors in an textfile, for example the
realignment paramters, you can
press the right mouse button, when SPM ask for the values and use the
'load from text-file' option.
I hope, this will answer some of your questions
Karsten
Anja Schlack wrote:
> I have a question concerning group analysis in spm99. In the first step
> of statistics, when I want to create the designmatrix it is very hard to
> type all this data in. Is it possible to create the Designmatrix in an
> matlab window by myself?
> I loaded the mat-file of an existing Designmatrix, but I don't
> understand the numbers in the array xX.X. I understood that the number
> of rows is the number of pictures of my data, and that the columns are
> the different conditions and sessions. Somehow the numbers seem to code
> for the onsettimes of stimulation (negative ones for no stimulation and
> positive ones for stimulation?), but what exactly do the floats code
> for?
>
> I hope you are able to help me,
> sincerely yours,
> anja schlack
--
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Dipl. phys. Karsten Specht
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Institut fuer Medizin | Institut fuer Allgemeine Psychologie
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