Hi Rita,
The easiest way to do this would be to first create a waveform using one of
the available options say a box car with the number of time points set to
the correct value. You will then need to save out this waveform as a user
defined file (Use the Save button). You could then use a text
editor(available in the waveform editor) to modify the numbers in this
waveform file to reflect the regressor you want to create.
To get a graphic illustration of your regressor you could use the Load
button in the Waveform editor.
Regards....Raj
*********************************************
Raj Jagannathan
Medical Products Division
Sensor Systems, Inc.
http://medx.sensor.com
*********************************************
----- Original Message -----
From: "Rita Rossi" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Monday, July 09, 2001 11:30 AM
Subject: Re: Analysing a covariate of interest in an fMRI study using SPM in
Medx
> Hello. Thanks for your reply. I have checked out the Medx manual on this
> issue but am not entirely clear on it. My understanding is that I need to
> create a waveform file by going to Functional and then Correlational
> Anaylsis...It appears that I should also create an Input File indicating
> the values of my covariate of interest and enter it in either the
> correlation or regression box, depending on which I want to do. I am not
> sure how to go about creating this Input File. I was wondering if perhaps
> you have a tutorial that I could run through that might help me understand
> it better?
> Thanks.
> Rita Rossi
>
> On Tue, 19 Jun 2001, Raj Jagannathan wrote:
>
> > Hi Rita,
> >
> > Looks like you are using SPM96 in MEDx3.3.
> >
> > You could do what you want by creating a custom waveform comprising your
> > covariate values and then using this waveform in your design. You would
need
> > to use User Defined for Response Type under the Data, Design and Numbers
> > Tab.
> >
> > Regards....Raj
> >
> > *********************************************
> > Raj Jagannathan
> > Medical Products Division
> > Sensor Systems, Inc.
> > http://medx.sensor.com
> >
> >
> > *********************************************
> >
> > ----- Original Message -----
> > From: "Rita" <[log in to unmask]>
> > To: <[log in to unmask]>
> > Sent: Thursday, June 14, 2001 1:55 PM
> > Subject: Analysing a covariate of interest in an fMRI study using SPM in
> > Medx
> >
> >
> > > In the SPM statistics modules in Medx, when analysing FMRI data, it
> > appears
> > > that a person can only enter confounds, but not covariates of
interest. I
> > > have a situation in which I would like to look at the effect of a
> > > performance measure on fMRI activation across subjects. How would I go
> > > about doing this? Is this possible?
> > > Thank you.
> > > Sincerely,
> > > Rita Rossi
> > >
> >
> >
>
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