Dear Lin,
You can create a fixed-effects model out of your subject-specific
SPM.mat files using the batch module:
SPM > Stats > Mixed-Effects (MFX) Analysis > FFX Specification
As a warning, the estimation of a MFX model in SPM will require a lot of
memory - usually, you need to have very specific reasons to use MFX
instead of the summary statistics approach.
Best regards,
Guillaume.
On 04/02/2021 16:40, Lin Wu wrote:
> HI,
> I am trying to do the Mixed-effects(MFX) but confused by the first step
> for FFX step.
> In the SPM12 Manual the MFX need a FFX step first.
> In the SPM12 Manual it says: 'It is essential that the design matrices
> contained in the SPM.mat files have the same number of columns. More
> specifically it is required that, over subjects, there be the same
> number of sessions, conditions per session, and columns per condition.'
> In my case I have 11 subjects, 1 session each, 8 separate conditions per
> session, and a covariate per each condition that depends on the
> condition. But the first-level analysis does not have this information.
> I have one SPM.mat for one corresponding rat and one angle. How can I
> add this information to the SPM.mat. Should I combine 8 SPM.mat for 8
> conditions into one SPM.mat. But how to do that in SPM?
> I will appreciate it if anyone also knows how to create the design
> matrix for the second-level analysis for the MFX step in this case.
> Regards
> Lin
--
Guillaume Flandin, PhD
Wellcome Centre for Human Neuroimaging
UCL Queen Square Institute of Neurology
London WC1N 3BG
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