Dear Davide,
As Mike mentioned, you probably want to model subject effects in your
within-subject design (either use the Flexible Factorial option with an
extra 'subject' factor, or consider having one factor with 12 levels and
use the One-way ANOVA within subject option). You also want to allow for
dependences between levels, using the Independent:No option for
non-sphericity).
There is an SPM function that can help you to specify contrasts for
factorial designs, spm_make_contrasts:
C = spm_make_contrasts([2 3 2]);
For example, the three-way interaction contrast is given by:
C(8).name
C(8).c
Best regards,
Guillaume.
On 02/11/16 03:39, Angstadt, Mike wrote:
> Davide,
>
> Since you have within subject factors you need to model this as either a
> Flexible Factorial design in SPM with a Subject factor, or use external
> modeling tools like GLM Flex to be able to model the repeated measures
> nature of the design properly.
>
> You can find information on Flexible Factorial designs by searching past
> messages on the list here. For GLM Flex, you can find information and
> download here: http://mrtools.mgh.harvard.edu/index.php?title=Main_Page
>
> -Mike
>
> --
> Mike Angstadt
> Research Computer Specialist / PANLab Lab Manager
> Department of Psychiatry / University of Michigan
> (734) 936-8229
>
> *From:* SPM (Statistical Parametric Mapping) [[log in to unmask]] on
> behalf of Davide Momi [[log in to unmask]]
> *Sent:* Tuesday, November 01, 2016 9:12 PM
> *To:* [log in to unmask]
> *Subject:* [SPM] Consultation
>
> Hello all,
>
> I am Davide Momi, research assistant at the
>
> Berenson-Allen Center for Noninvasive Brain Stimulation - Harvard
> University - Boston. Thanks to your toolbox, I'm analyzing my
> neuroimmaging data.
>
> I've configurated a second-level factorial design with 3 factor:
> Factor A (2 levels)- task inside scanner (rest vs motor)
> Factor B (3 levels)- treatment within subjects
> Factor C (3 levels)- time (pre vs post)
>
>
> I wish to know how can I interpret my results. I've attached an example
> of triple Positive interaction
> Could you explain which kind of contrast represent? Could you give me
> several tips on how make new contrast?
>
> Please let me know
>
> Thanks you in advice
>
> Davide Momi
> -----------
> Research Assistant
> Berenson-Allen Center for Noninvasive Brain Stimulation
> Beth Israel Deaconess Medical Center | Harvard Medical School
> 330 Brookline Avenue, KS-423, Boston, MA 02215
> Mobile ++39 - 348-2650293
>
> **********************************************************
> Electronic Mail is not secure, may not be read every day, and should not
> be used for urgent or sensitive issues
>
--
Guillaume Flandin, PhD
Wellcome Trust Centre for Neuroimaging
University College London
12 Queen Square
London WC1N 3BG
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