Hi,
On 31 Jul 2009, at 12:09, Bertram Walter wrote:
> Hi,
>
> the documentation of FEAT for Multi-Session & Multi-Subject
> (Repeated Measures - Three Level Analysis) (http://www.fmrib.ox.ac.uk/fsl/feat5/detail.html#higher
> ) suggests to perform a single fixed effects model with all
> subjects. Previous versions of the documentation recommend a
> separate model for each subject. Why this was changed?
This is pretty arbitrary: _IF_ your second-level model is FE, then
it makes almost no difference whether you carry out the different
subject's modellings in one big model or separately.
Cheers, Steve.
>
> Furthermore, the documentation suggests for the subsequent third
> level analysis:
> 'Now we want the mean group effect, across subjects, achieved with a
> third-level ME analysis. Select Inputs are lower-level FEAT
> directories and select the 5 relevant directories created at second-
> level, named something like subject_N.gfeat/cope1.feat.'
> This was left unchanged. It confuses me a little as a
> 'subject_N.gfeat/cope1.feat' directory exists only if a second level
> analysis was performed for each subject.
>
> Best regards
> Bertram
>
> --
> Dr. Bertram Walter
> Bender Institute of Neuroimaging
> University of Giessen
> Otto-Behaghel-Str. 10H
> 35394 Giessen
> Germany
> Phone +49 (641) 99-26307
> or +49 (641) 99-26331 (Secretary)
> Fax +49 (641) 99-26309
>
---------------------------------------------------------------------------
Stephen M. Smith, Professor of Biomedical Engineering
Associate Director, Oxford University FMRIB Centre
FMRIB, JR Hospital, Headington, Oxford OX3 9DU, UK
+44 (0) 1865 222726 (fax 222717)
[log in to unmask] http://www.fmrib.ox.ac.uk/~steve
---------------------------------------------------------------------------
|